Merge branch 'feature/usb_console_ig' into 'master'

add USB CDC as a console option

Closes IDF-1620

See merge request espressif/esp-idf!8459

components/bootloader/subproject/main/ld/esp32/bootloader.ld

@@ -45,6 +45,7 @@ SECTIONS
     *libbootloader_support.a:bootloader_efuse_esp32.*(.literal .text .literal.* .text.*)
     *libbootloader_support.a:bootloader_utility.*(.literal .text .literal.* .text.*)
     *libbootloader_support.a:bootloader_sha.*(.literal .text .literal.* .text.*)
+    *libbootloader_support.a:bootloader_console_loader.*(.literal .text .literal.* .text.*)
     *libbootloader_support.a:esp_image_format.*(.literal .text .literal.* .text.*)
     *libbootloader_support.a:flash_encrypt.*(.literal .text .literal.* .text.*)
     *libbootloader_support.a:flash_partitions.*(.literal .text .literal.* .text.*)

components/bootloader/subproject/main/ld/esp32s2/bootloader.ld

@@ -31,6 +31,7 @@ SECTIONS
     *libbootloader_support.a:bootloader_efuse_esp32s2.*(.literal .text .literal.* .text.*)
     *libbootloader_support.a:bootloader_utility.*(.literal .text .literal.* .text.*)
     *libbootloader_support.a:bootloader_sha.*(.literal .text .literal.* .text.*)
+    *libbootloader_support.a:bootloader_console_loader.*(.literal .text .literal.* .text.*)
     *libbootloader_support.a:esp_image_format.*(.literal .text .literal.* .text.*)
     *libbootloader_support.a:flash_encrypt.*(.literal .text .literal.* .text.*)
     *libbootloader_support.a:flash_partitions.*(.literal .text .literal.* .text.*)

components/bootloader_support/CMakeLists.txt

@@ -18,6 +18,8 @@ if(BOOTLOADER_BUILD)
     set(priv_requires micro-ecc spi_flash efuse)
     list(APPEND srcs
     "src/bootloader_init.c"
+    "src/bootloader_console.c"
+    "src/bootloader_console_loader.c"
     "src/${IDF_TARGET}/bootloader_sha.c"
     "src/${IDF_TARGET}/flash_encrypt.c"
     "src/${IDF_TARGET}/bootloader_${IDF_TARGET}.c"

components/bootloader_support/include_bootloader/bootloader_console.h

@@ -0,0 +1,31 @@
+// Copyright 2020 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+/**
+ * @brief Initialize console output (UART or USB)
+ */
+void bootloader_console_init(void);
+
+/**
+ * @brief Flush and otherwise de-initialize console output.
+ */
+void bootloader_console_deinit(void);
+
+/**
+ * @brief "Write character to USB" function for ets_install_putc1.
+ * Only defined if USB CDC is used for console output.
+ */
+void bootloader_console_write_char_usb(char c);

components/bootloader_support/include_bootloader/bootloader_utility.h

@@ -75,6 +75,11 @@ void bootloader_utility_load_boot_image_from_deep_sleep(void);
  */
 __attribute__((noreturn)) void bootloader_reset(void);
 
+/**
+ * @brief Do any cleanup before exiting the bootloader, before starting the app or resetting
+ */
+void bootloader_atexit(void);
+
 /**
  * @brief Converts an array to a printable string.
  *

components/bootloader_support/src/bootloader_clock.c

@@ -21,9 +21,11 @@
 #ifdef CONFIG_IDF_TARGET_ESP32
 #include "esp32/rom/uart.h"
 #include "esp32/rom/rtc.h"
+#define CPU_RESET_REASON SW_CPU_RESET
 #elif CONFIG_IDF_TARGET_ESP32S2
 #include "esp32s2/rom/uart.h"
 #include "esp32s2/rom/rtc.h"
+#define CPU_RESET_REASON RTC_SW_CPU_RESET
 #endif
 
 void bootloader_clock_configure(void)
@@ -50,21 +52,22 @@ void bootloader_clock_configure(void)
         cpu_freq_mhz = 240;
     }
 #endif
-
-    rtc_clk_config_t clk_cfg = RTC_CLK_CONFIG_DEFAULT();
-#if CONFIG_IDF_TARGET_ESP32
-    clk_cfg.xtal_freq = CONFIG_ESP32_XTAL_FREQ;
-#endif
-    /* ESP32-S2 doesn't have XTAL_FREQ choice, always 40MHz */
-    clk_cfg.cpu_freq_mhz = cpu_freq_mhz;
-    clk_cfg.slow_freq = rtc_clk_slow_freq_get();
-    clk_cfg.fast_freq = rtc_clk_fast_freq_get();
-    rtc_clk_init(clk_cfg);
-    /* As a slight optimization, if 32k XTAL was enabled in sdkconfig, we enable
-     * it here. Usually it needs some time to start up, so we amortize at least
-     * part of the start up time by enabling 32k XTAL early.
-     * App startup code will wait until the oscillator has started up.
-     */
+    if (rtc_clk_apb_freq_get() < APB_CLK_FREQ || rtc_get_reset_reason(0) != CPU_RESET_REASON) {
+        rtc_clk_config_t clk_cfg = RTC_CLK_CONFIG_DEFAULT();
+    #if CONFIG_IDF_TARGET_ESP32
+        clk_cfg.xtal_freq = CONFIG_ESP32_XTAL_FREQ;
+    #endif
+        /* ESP32-S2 doesn't have XTAL_FREQ choice, always 40MHz */
+        clk_cfg.cpu_freq_mhz = cpu_freq_mhz;
+        clk_cfg.slow_freq = rtc_clk_slow_freq_get();
+        clk_cfg.fast_freq = rtc_clk_fast_freq_get();
+        rtc_clk_init(clk_cfg);
+        /* As a slight optimization, if 32k XTAL was enabled in sdkconfig, we enable
+        * it here. Usually it needs some time to start up, so we amortize at least
+        * part of the start up time by enabling 32k XTAL early.
+        * App startup code will wait until the oscillator has started up.
+        */
+    }
 
     /* TODO: move the clock option into esp_system, so that this doesn't have
      * to continue:

components/bootloader_support/src/bootloader_console.c

@@ -0,0 +1,104 @@
+// Copyright 2020 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "sdkconfig.h"
+#include "bootloader_console.h"
+#include "soc/uart_periph.h"
+#include "soc/uart_channel.h"
+#include "soc/io_mux_reg.h"
+#include "soc/gpio_periph.h"
+#include "soc/gpio_sig_map.h"
+#include "soc/rtc.h"
+#include "hal/clk_gate_ll.h"
+#ifdef CONFIG_IDF_TARGET_ESP32
+#include "esp32/rom/ets_sys.h"
+#include "esp32/rom/uart.h"
+#include "esp32/rom/gpio.h"
+#elif CONFIG_IDF_TARGET_ESP32S2
+#include "esp32s2/rom/ets_sys.h"
+#include "esp32s2/rom/uart.h"
+#include "esp32s2/rom/gpio.h"
+#include "esp32s2/rom/usb/cdc_acm.h"
+#include "esp32s2/rom/usb/usb_common.h"
+#endif
+
+#ifdef CONFIG_ESP_CONSOLE_UART_NONE
+void bootloader_console_init(void)
+{
+    ets_install_putc1(NULL);
+    ets_install_putc2(NULL);
+}
+#endif // CONFIG_ESP_CONSOLE_UART_NONE
+
+#ifdef CONFIG_ESP_CONSOLE_UART
+void bootloader_console_init(void)
+{
+    const int uart_num = CONFIG_ESP_CONSOLE_UART_NUM;
+
+    ets_install_uart_printf();
+
+    // Wait for UART FIFO to be empty.
+    uart_tx_wait_idle(0);
+
+#if CONFIG_ESP_CONSOLE_UART_CUSTOM
+    // Some constants to make the following code less upper-case
+    const int uart_tx_gpio = CONFIG_ESP_CONSOLE_UART_TX_GPIO;
+    const int uart_rx_gpio = CONFIG_ESP_CONSOLE_UART_RX_GPIO;
+    // Switch to the new UART (this just changes UART number used for
+    // ets_printf in ROM code).
+    uart_tx_switch(uart_num);
+    // If console is attached to UART1 or if non-default pins are used,
+    // need to reconfigure pins using GPIO matrix
+    if (uart_num != 0 ||
+            uart_tx_gpio != UART_NUM_0_TXD_DIRECT_GPIO_NUM ||
+            uart_rx_gpio != UART_NUM_0_RXD_DIRECT_GPIO_NUM) {
+        // Change default UART pins back to GPIOs
+        PIN_FUNC_SELECT(PERIPHS_IO_MUX_U0RXD_U, PIN_FUNC_GPIO);
+        PIN_FUNC_SELECT(PERIPHS_IO_MUX_U0TXD_U, PIN_FUNC_GPIO);
+        // Route GPIO signals to/from pins
+        const uint32_t tx_idx = uart_periph_signal[uart_num].tx_sig;
+        const uint32_t rx_idx = uart_periph_signal[uart_num].rx_sig;
+        PIN_INPUT_ENABLE(GPIO_PIN_MUX_REG[uart_rx_gpio]);
+        gpio_pad_pullup(uart_rx_gpio);
+        gpio_matrix_out(uart_tx_gpio, tx_idx, 0, 0);
+        gpio_matrix_in(uart_rx_gpio, rx_idx, 0);
+        // Enable the peripheral
+        periph_ll_enable_clk_clear_rst(PERIPH_UART0_MODULE + uart_num);
+    }
+#endif // CONFIG_ESP_CONSOLE_UART_CUSTOM
+
+    // Set configured UART console baud rate
+    const int uart_baud = CONFIG_ESP_CONSOLE_UART_BAUDRATE;
+    uart_div_modify(uart_num, (rtc_clk_apb_freq_get() << 4) / uart_baud);
+}
+#endif // CONFIG_ESP_CONSOLE_UART
+
+#ifdef CONFIG_ESP_CONSOLE_USB_CDC
+/* Buffer for CDC data structures. No RX buffer allocated. */
+static char s_usb_cdc_buf[CDC_ACM_WORK_BUF_MIN];
+
+void bootloader_console_init(void)
+{
+#ifdef CONFIG_IDF_TARGET_ESP32S2
+    /* ESP32-S2 specific patch to set the correct serial number in the descriptor.
+     * Later chips don't need this.
+     */
+    rom_usb_cdc_set_descriptor_patch();
+#endif
+
+    Uart_Init_USB(s_usb_cdc_buf, sizeof(s_usb_cdc_buf));
+    uart_tx_switch(ROM_UART_USB);
+    ets_install_putc1(bootloader_console_write_char_usb);
+}
+#endif //CONFIG_ESP_CONSOLE_USB_CDC

components/bootloader_support/src/bootloader_console_loader.c

@@ -0,0 +1,89 @@
+// Copyright 2020 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/**
+ * This file is contains console-related functions which should be located in iram_loader_seg,
+ * to be available in the "loader" phase, when iram_seg may be overwritten.
+ */
+#include <stdint.h>
+#include <stddef.h>
+#include "sdkconfig.h"
+#include "bootloader_console.h"
+#ifdef CONFIG_IDF_TARGET_ESP32
+#include "esp32/rom/ets_sys.h"
+#include "esp32/rom/uart.h"
+#elif CONFIG_IDF_TARGET_ESP32S2
+#include "esp32s2/rom/ets_sys.h"
+#include "esp32s2/rom/uart.h"
+#include "esp32s2/rom/usb/chip_usb_dw_wrapper.h"
+#include "esp32s2/rom/usb/usb_dc.h"
+#include "esp32s2/rom/usb/cdc_acm.h"
+#include "esp32s2/rom/usb/usb_persist.h"
+#endif
+
+#ifdef CONFIG_ESP_CONSOLE_USB_CDC
+/* The following functions replace ets_write_char_uart, uart_tx_one_char,
+ * and uart_tx_one_char_uart ROM functions. The main difference is that
+ * uart_tx_one_char_uart calls cdc_acm_fifo_fill for each byte passed to it,
+ * which results in very slow console output. The version here uses a TX buffer.
+ * It also doesn't handle UART output, only works with USB.
+ */
+static char cdc_txbuf[ACM_BYTES_PER_TX];
+static size_t cdc_txpos;
+
+static void bootloader_console_flush_usb(void)
+{
+    cdc_acm_fifo_fill(uart_acm_dev, (const uint8_t *) cdc_txbuf, cdc_txpos);
+    /* return value ignored — if bootloader fails to log something, proceed anyway */
+    cdc_txpos = 0;
+}
+
+static void bootloader_console_write_one_char_usb(char ch)
+{
+    cdc_txbuf[cdc_txpos++] = ch;
+    if (ch == '\n' || cdc_txpos == sizeof(cdc_txbuf)) {
+        bootloader_console_flush_usb();
+    }
+}
+
+void bootloader_console_write_char_usb(char c)
+{
+    if (c == '\n') {
+        bootloader_console_write_one_char_usb('\r');
+        bootloader_console_write_one_char_usb('\n');
+    } else if (c == '\r') {
+    } else {
+        bootloader_console_write_one_char_usb(c);
+    }
+}
+#endif //CONFIG_ESP_CONSOLE_USB_CDC
+
+void bootloader_console_deinit(void)
+{
+#ifdef CONFIG_ESP_CONSOLE_UART
+    /* Ensure any buffered log output is displayed */
+    uart_tx_flush(CONFIG_ESP_CONSOLE_UART_NUM);
+#endif // CONFIG_ESP_CONSOLE_UART
+
+#ifdef CONFIG_ESP_CONSOLE_USB_CDC
+    bootloader_console_flush_usb();
+    usb_dc_prepare_persist();
+    chip_usb_set_persist_flags(USBDC_PERSIST_ENA);
+    ets_delay_us(100);
+    for (int i = 0; i < 10; i++) {
+        usb_dc_check_poll_for_interrupts();
+    }
+    ets_install_putc1(NULL);
+#endif
+}

components/bootloader_support/src/bootloader_utility.c

@@ -63,6 +63,7 @@
 #include "bootloader_common.h"
 #include "bootloader_utility.h"
 #include "bootloader_sha.h"
+#include "bootloader_console.h"
 #include "esp_efuse.h"
 
 static const char *TAG = "boot";
@@ -757,6 +758,7 @@ static void set_cache_and_start_app(
     // Application will need to do Cache_Flush(1) and Cache_Read_Enable(1)
 
     ESP_LOGD(TAG, "start: 0x%08x", entry_addr);
+    bootloader_atexit();
     typedef void (*entry_t)(void) __attribute__((noreturn));
     entry_t entry = ((entry_t) entry_addr);
 
@@ -768,8 +770,7 @@ static void set_cache_and_start_app(
 void bootloader_reset(void)
 {
 #ifdef BOOTLOADER_BUILD
-    uart_tx_flush(0);    /* Ensure any buffered log output is displayed */
-    uart_tx_flush(1);
+    bootloader_atexit();
     ets_delay_us(1000); /* Allow last byte to leave FIFO */
     REG_WRITE(RTC_CNTL_OPTIONS0_REG, RTC_CNTL_SW_SYS_RST);
     while (1) { }       /* This line will never be reached, used to keep gcc happy */
@@ -778,6 +779,11 @@ void bootloader_reset(void)
 #endif
 }
 
+void bootloader_atexit(void)
+{
+    bootloader_console_deinit();
+}
+
 esp_err_t bootloader_sha256_hex_to_str(char *out_str, const uint8_t *in_array_hex, size_t len)
 {
     if (out_str == NULL || in_array_hex == NULL || len == 0) {

components/bootloader_support/src/esp32/bootloader_esp32.c

@@ -23,6 +23,7 @@
 #include "bootloader_common.h"
 #include "bootloader_flash_config.h"
 #include "bootloader_mem.h"
+#include "bootloader_console.h"
 
 #include "soc/cpu.h"
 #include "soc/dport_reg.h"
@@ -277,59 +278,6 @@ static esp_err_t bootloader_init_spi_flash(void)
     return ESP_OK;
 }
 
-static void bootloader_init_uart_console(void)
-{
-#if CONFIG_ESP_CONSOLE_UART_NONE
-    ets_install_putc1(NULL);
-    ets_install_putc2(NULL);
-#else // CONFIG_ESP_CONSOLE_UART_NONE
-    const int uart_num = CONFIG_ESP_CONSOLE_UART_NUM;
-
-    uartAttach();
-    ets_install_uart_printf();
-
-    // Wait for UART FIFO to be empty.
-    uart_tx_wait_idle(0);
-
-#if CONFIG_ESP_CONSOLE_UART_CUSTOM
-    // Some constants to make the following code less upper-case
-    const int uart_tx_gpio = CONFIG_ESP_CONSOLE_UART_TX_GPIO;
-    const int uart_rx_gpio = CONFIG_ESP_CONSOLE_UART_RX_GPIO;
-    // Switch to the new UART (this just changes UART number used for
-    // ets_printf in ROM code).
-    uart_tx_switch(uart_num);
-    // If console is attached to UART1 or if non-default pins are used,
-    // need to reconfigure pins using GPIO matrix
-    if (uart_num != 0 || uart_tx_gpio != 1 || uart_rx_gpio != 3) {
-        // Change pin mode for GPIO1/3 from UART to GPIO
-        PIN_FUNC_SELECT(PERIPHS_IO_MUX_U0RXD_U, FUNC_U0RXD_GPIO3);
-        PIN_FUNC_SELECT(PERIPHS_IO_MUX_U0TXD_U, FUNC_U0TXD_GPIO1);
-        // Route GPIO signals to/from pins
-        // (arrays should be optimized away by the compiler)
-        const uint32_t tx_idx_list[3] = {U0TXD_OUT_IDX, U1TXD_OUT_IDX, U2TXD_OUT_IDX};
-        const uint32_t rx_idx_list[3] = {U0RXD_IN_IDX, U1RXD_IN_IDX, U2RXD_IN_IDX};
-        const uint32_t uart_reset[3] = {DPORT_UART_RST, DPORT_UART1_RST, DPORT_UART2_RST};
-        const uint32_t tx_idx = tx_idx_list[uart_num];
-        const uint32_t rx_idx = rx_idx_list[uart_num];
-
-        PIN_INPUT_ENABLE(GPIO_PIN_MUX_REG[uart_rx_gpio]);
-        gpio_pad_pullup(uart_rx_gpio);
-
-        gpio_matrix_out(uart_tx_gpio, tx_idx, 0, 0);
-        gpio_matrix_in(uart_rx_gpio, rx_idx, 0);
-
-        DPORT_SET_PERI_REG_MASK(DPORT_PERIP_RST_EN_REG, uart_reset[uart_num]);
-        DPORT_CLEAR_PERI_REG_MASK(DPORT_PERIP_RST_EN_REG, uart_reset[uart_num]);
-    }
-#endif // CONFIG_ESP_CONSOLE_UART_CUSTOM
-
-    // Set configured UART console baud rate
-    const int uart_baud = CONFIG_ESP_CONSOLE_UART_BAUDRATE;
-    uart_div_modify(uart_num, (rtc_clk_apb_freq_get() << 4) / uart_baud);
-
-#endif // CONFIG_ESP_CONSOLE_UART_NONE
-}
-
 static void wdt_reset_cpu0_info_enable(void)
 {
     //We do not reset core1 info here because it didn't work before cpu1 was up. So we put it into call_start_cpu1.
@@ -452,7 +400,7 @@ esp_err_t bootloader_init(void)
     // config clock
     bootloader_clock_configure();
     // initialize uart console, from now on, we can use esp_log
-    bootloader_init_uart_console();
+    bootloader_console_init();
     /* print 2nd bootloader banner */
     bootloader_print_banner();
     // update flash ID

components/bootloader_support/src/esp32s2/bootloader_esp32s2.c

@@ -26,12 +26,13 @@
 #include "bootloader_clock.h"
 #include "bootloader_flash_config.h"
 #include "bootloader_mem.h"
+#include "bootloader_console.h"
 
 #include "esp32s2/rom/cache.h"
 #include "esp32s2/rom/ets_sys.h"
 #include "esp32s2/rom/spi_flash.h"
 #include "esp32s2/rom/rtc.h"
-#include "esp32s2/rom/uart.h"
+
 #include "esp_attr.h"
 #include "esp_log.h"
 #include "esp_image_format.h"
@@ -216,59 +217,6 @@ static esp_err_t bootloader_init_spi_flash(void)
     return ESP_OK;
 }
 
-static void bootloader_init_uart_console(void)
-{
-#if CONFIG_ESP_CONSOLE_UART_NONE
-    ets_install_putc1(NULL);
-    ets_install_putc2(NULL);
-#else // CONFIG_ESP_CONSOLE_UART_NONE
-    const int uart_num = CONFIG_ESP_CONSOLE_UART_NUM;
-
-    uartAttach(NULL);
-    ets_install_uart_printf();
-
-    // Wait for UART FIFO to be empty.
-    uart_tx_wait_idle(0);
-
-#if CONFIG_ESP_CONSOLE_UART_CUSTOM
-    // Some constants to make the following code less upper-case
-    const int uart_tx_gpio = CONFIG_ESP_CONSOLE_UART_TX_GPIO;
-    const int uart_rx_gpio = CONFIG_ESP_CONSOLE_UART_RX_GPIO;
-    // Switch to the new UART (this just changes UART number used for
-    // ets_printf in ROM code).
-    uart_tx_switch(uart_num);
-    // If console is attached to UART1 or if non-default pins are used,
-    // need to reconfigure pins using GPIO matrix
-    if (uart_num != 0 || uart_tx_gpio != 43 || uart_rx_gpio != 44) {
-        // Change pin mode UART to GPIO
-        PIN_FUNC_SELECT(PERIPHS_IO_MUX_U0RXD_U, FUNC_U0RXD_GPIO44);
-        PIN_FUNC_SELECT(PERIPHS_IO_MUX_U0TXD_U, FUNC_U0TXD_GPIO43);
-        // Route GPIO signals to/from pins
-        // (arrays should be optimized away by the compiler)
-        const uint32_t tx_idx_list[2] = {U0TXD_OUT_IDX, U1TXD_OUT_IDX};
-        const uint32_t rx_idx_list[2] = {U0RXD_IN_IDX, U1RXD_IN_IDX};
-        const uint32_t uart_reset[2] = {DPORT_UART_RST, DPORT_UART1_RST};
-        const uint32_t tx_idx = tx_idx_list[uart_num];
-        const uint32_t rx_idx = rx_idx_list[uart_num];
-
-        PIN_INPUT_ENABLE(GPIO_PIN_MUX_REG[uart_rx_gpio]);
-        gpio_pad_pullup(uart_rx_gpio);
-
-        gpio_matrix_out(uart_tx_gpio, tx_idx, 0, 0);
-        gpio_matrix_in(uart_rx_gpio, rx_idx, 0);
-
-        DPORT_SET_PERI_REG_MASK(DPORT_PERIP_RST_EN_REG, uart_reset[uart_num]);
-        DPORT_CLEAR_PERI_REG_MASK(DPORT_PERIP_RST_EN_REG, uart_reset[uart_num]);
-    }
-#endif // CONFIG_ESP_CONSOLE_UART_CUSTOM
-
-    // Set configured UART console baud rate
-    const int uart_baud = CONFIG_ESP_CONSOLE_UART_BAUDRATE;
-    uart_div_modify(uart_num, (rtc_clk_apb_freq_get() << 4) / uart_baud);
-
-#endif // CONFIG_ESP_CONSOLE_UART_NONE
-}
-
 static void wdt_reset_cpu0_info_enable(void)
 {
     DPORT_REG_SET_BIT(DPORT_PERI_CLK_EN_REG, DPORT_PERI_EN_ASSIST_DEBUG);
@@ -366,8 +314,8 @@ esp_err_t bootloader_init(void)
     bootloader_reset_mmu();
     // config clock
     bootloader_clock_configure();
-    // initialize uart console, from now on, we can use esp_log
-    bootloader_init_uart_console();
+    // initialize console, from now on, we can use esp_log
+    bootloader_console_init();
     /* print 2nd bootloader banner */
     bootloader_print_banner();
     // update flash ID

components/console/linenoise/linenoise.c

@@ -203,6 +203,13 @@ void linenoiseSetDumbMode(int set) {
     dumbmode = set;
 }
 
+static void flushWrite(void) {
+    if (__fbufsize(stdout) > 0) {
+        fflush(stdout);
+    }
+    fsync(fileno(stdout));
+}
+
 /* Use the ESC [6n escape sequence to query the horizontal cursor position
  * and return it. On error -1 is returned, on success the position of the
  * cursor. */
@@ -213,7 +220,7 @@ static int getCursorPosition(void) {
 
     /* Report cursor location */
     fprintf(stdout, "\x1b[6n");
-
+    flushWrite();
     /* Read the response: ESC [ rows ; cols R */
     while (i < sizeof(buf)-1) {
         if (fread(buf+i, 1, 1, stdin) != 1) break;
@@ -238,6 +245,7 @@ static int getColumns(void) {
 
     /* Go to right margin and get position. */
     if (fwrite("\x1b[999C", 1, 6, stdout) != 6) goto failed;
+    flushWrite();
     cols = getCursorPosition();
     if (cols == -1) goto failed;
 
@@ -248,6 +256,7 @@ static int getColumns(void) {
         if (fwrite(seq, 1, strlen(seq), stdout) == -1) {
             /* Can't recover... */
         }
+        flushWrite();
     }
     return cols;
 
@@ -258,12 +267,14 @@ failed:
 /* Clear the screen. Used to handle ctrl+l */
 void linenoiseClearScreen(void) {
     fprintf(stdout,"\x1b[H\x1b[2J");
+    flushWrite();
 }
 
 /* Beep, used for completion when there is nothing to complete or when all
  * the choices were already shown. */
 static void linenoiseBeep(void) {
     fprintf(stdout, "\x7");
+    flushWrite();
 }
 
 /* ============================== Completion ================================ */
@@ -468,6 +479,7 @@ static void refreshSingleLine(struct linenoiseState *l) {
     snprintf(seq,64,"\r\x1b[%dC", (int)(pos+plen));
     abAppend(&ab,seq,strlen(seq));
     if (fwrite(ab.b, ab.len, 1, stdout) == -1) {} /* Can't recover from write error. */
+    flushWrite();
     abFree(&ab);
 }
 
@@ -555,6 +567,7 @@ static void refreshMultiLine(struct linenoiseState *l) {
     l->oldpos = l->pos;
 
     if (fwrite(ab.b,ab.len,1,stdout) == -1) {} /* Can't recover from write error. */
+    flushWrite();
     abFree(&ab);
 }
 
@@ -581,6 +594,7 @@ int linenoiseEditInsert(struct linenoiseState *l, char c) {
                 /* Avoid a full update of the line in the
                  * trivial case. */
                 if (fwrite(&c,1,1,stdout) == -1) return -1;
+                flushWrite();
             } else {
                 refreshLine(l);
             }
@@ -726,6 +740,7 @@ static int linenoiseEdit(char *buf, size_t buflen, const char *prompt)
 
     int pos1 = getCursorPosition();
     if (fwrite(prompt,l.plen,1,stdout) == -1) return -1;
+    flushWrite();
     int pos2 = getCursorPosition();
     if (pos1 >= 0 && pos2 >= 0) {
         l.plen = pos2 - pos1;
@@ -881,9 +896,7 @@ static int linenoiseEdit(char *buf, size_t buflen, const char *prompt)
             linenoiseEditDeletePrevWord(&l);
             break;
         }
-        if (__fbufsize(stdout) > 0) {
-            fflush(stdout);
-        }
+        flushWrite();
     }
     return l.len;
 }
@@ -894,14 +907,16 @@ void linenoiseAllowEmpty(bool val) {
 
 int linenoiseProbe(void) {
     /* Switch to non-blocking mode */
-    int flags = fcntl(STDIN_FILENO, F_GETFL);
+    int stdin_fileno = fileno(stdin);
+    int flags = fcntl(stdin_fileno, F_GETFL);
     flags |= O_NONBLOCK;
-    int res = fcntl(STDIN_FILENO, F_SETFL, flags);
+    int res = fcntl(stdin_fileno, F_SETFL, flags);
     if (res != 0) {
         return -1;
     }
     /* Device status request */
     fprintf(stdout, "\x1b[5n");
+    flushWrite();
 
     /* Try to read response */
     int timeout_ms = 200;
@@ -915,7 +930,7 @@ int linenoiseProbe(void) {
     }
     /* Restore old mode */
     flags &= ~O_NONBLOCK;
-    res = fcntl(STDIN_FILENO, F_SETFL, flags);
+    res = fcntl(stdin_fileno, F_SETFL, flags);
     if (res != 0) {
         return -1;
     }
@@ -935,6 +950,7 @@ static int linenoiseRaw(char *buf, size_t buflen, const char *prompt) {
 
     count = linenoiseEdit(buf, buflen, prompt);
     fputc('\n', stdout);
+    flushWrite();
     return count;
 }
 
@@ -961,6 +977,7 @@ static int linenoiseDumb(char* buf, size_t buflen, const char* prompt) {
         fputc(c, stdout); /* echo */
     }
     fputc('\n', stdout);
+    flushWrite();
     return count;
 }
 

components/driver/test/test_uart.c

@@ -296,6 +296,7 @@ TEST_CASE("uart tx with ringbuffer test", "[uart]")
         .rx_flow_ctrl_thresh = 120,
         .source_clk = UART_SCLK_APB,
     };
+    uart_wait_tx_idle_polling(uart_num);
     TEST_ESP_OK(uart_param_config(uart_num, &uart_config));
     TEST_ESP_OK(uart_driver_install(uart_num, 1024 * 2, 1024 *2, 20, NULL, 0));
     TEST_ESP_OK(uart_set_loop_back(uart_num, true));

components/esp32s2/Kconfig

@@ -498,6 +498,14 @@ menu "ESP32S2-specific"
             If enabled, this disables the linking of binary libraries in the application build. Note
             that after enabling this Wi-Fi/Bluetooth will not work.
 
+    config ESP32S2_KEEP_USB_ALIVE
+        bool "Keep USB peripheral enabled at start up" if !ESP_CONSOLE_USB_CDC
+        default y if ESP_CONSOLE_USB_CDC
+        help
+            During the application initialization process, all the peripherals except UARTs and timers
+            are reset. Enable this option to keep USB peripheral enabled.
+            This option is automatically enabled if "USB CDC" console is selected.
+
     config ESP32S2_RTCDATA_IN_FAST_MEM
         bool "Place RTC_DATA_ATTR and RTC_RODATA_ATTR variables into RTC fast memory segment"
         default n

components/esp_common/Kconfig

@@ -62,33 +62,45 @@ menu "Common ESP-related"
             with shared stack.
 
     choice ESP_CONSOLE_UART
-        prompt "UART for console output"
+        prompt "Channel for console output"
         default ESP_CONSOLE_UART_DEFAULT
         help
-            Select whether to use UART for console output (through stdout and stderr).
+            Select where to send console output (through stdout and stderr).
 
             - Default is to use UART0 on pre-defined GPIOs.
             - If "Custom" is selected, UART0 or UART1 can be chosen,
               and any pins can be selected.
             - If "None" is selected, there will be no console output on any UART, except
-              for initial output from ROM bootloader. This output can be further suppressed by
-              bootstrapping GPIO13 pin to low logic level.
-
+              for initial output from ROM bootloader. This ROM output can be suppressed by
+              GPIO strapping or EFUSE, refer to chip datasheet for details.
+            - On chips with USB peripheral, "USB CDC" option redirects output to the
+              CDC port. This option uses the CDC driver in the chip ROM.
+              This option is incompatible with TinyUSB stack.
         config ESP_CONSOLE_UART_DEFAULT
             bool "Default: UART0"
+        config ESP_CONSOLE_USB_CDC
+            bool "USB CDC"
+            # The naming is confusing: USB_ENABLED means that TinyUSB driver is enabled, not USB in general.
+            # && !USB_ENABLED is because the ROM CDC driver is currently incompatible with TinyUSB.
+            depends on IDF_TARGET_ESP32S2 && !USB_ENABLED
         config ESP_CONSOLE_UART_CUSTOM
-            bool "Custom"
-        config ESP_CONSOLE_UART_NONE
+            bool "Custom UART"
+        config ESP_CONSOLE_NONE
             bool "None"
     endchoice
 
+    # Internal option, indicates that console UART is used (and not USB, for example)
+    config ESP_CONSOLE_UART
+        bool
+        default y if ESP_CONSOLE_UART_DEFAULT || ESP_CONSOLE_UART_CUSTOM
+
     choice ESP_CONSOLE_UART_NUM
         prompt "UART peripheral to use for console output (0-1)"
         depends on ESP_CONSOLE_UART_CUSTOM
         default ESP_CONSOLE_UART_CUSTOM_NUM_0
         help
-            Due of a ROM bug, UART2 is not supported for console output
-            via ets_printf.
+            Select which UART peripheral to use for console output.
+            On ESP32, UART2 is not supported for console output via ets_printf.
 
         config ESP_CONSOLE_UART_CUSTOM_NUM_0
             bool "UART0"
@@ -98,28 +110,48 @@ menu "Common ESP-related"
 
     config ESP_CONSOLE_UART_NUM
         int
-        default 0 if ESP_CONSOLE_UART_DEFAULT || ESP_CONSOLE_UART_NONE
+        default 0 if ESP_CONSOLE_UART_DEFAULT
         default 0 if ESP_CONSOLE_UART_CUSTOM_NUM_0
         default 1 if ESP_CONSOLE_UART_CUSTOM_NUM_1
+        default -1 if !ESP_CONSOLE_UART
 
     config ESP_CONSOLE_UART_TX_GPIO
         int "UART TX on GPIO#"
+        depends on ESP_CONSOLE_UART_CUSTOM
         range 0 46
         default 1 if IDF_TARGET_ESP32
         default 43 if IDF_TARGET_ESP32S2
 
     config ESP_CONSOLE_UART_RX_GPIO
         int "UART RX on GPIO#"
+        depends on ESP_CONSOLE_UART_CUSTOM
         range 0 46
         default 3 if IDF_TARGET_ESP32
         default 44 if IDF_TARGET_ESP32S2
 
     config ESP_CONSOLE_UART_BAUDRATE
-        int "UART console baud rate"
-        depends on !ESP_CONSOLE_UART_NONE
+        int
+        prompt "UART console baud rate" if ESP_CONSOLE_UART_CUSTOM
+        depends on ESP_CONSOLE_UART
         default 115200
         range 1200 4000000
 
+    config ESP_CONSOLE_USB_CDC_RX_BUF_SIZE
+        int "Size of USB CDC RX buffer"
+        depends on ESP_CONSOLE_USB_CDC
+        default 64
+        range 4 16384
+        help
+            Set the size of USB CDC RX buffer. Increase the buffer size if your application
+            is often receiving data over USB CDC.
+
+    config ESP_CONSOLE_USB_CDC_SUPPORT_ETS_PRINTF
+        bool "Enable ets_printf / ESP_EARLY_LOG via USB CDC"
+        depends on ESP_CONSOLE_USB_CDC
+        default n
+        help
+            If enabled, ets_printf and ESP_EARLY_LOG output will also be sent over USB CDC.
+            Disabling this option saves about 1kB or RAM.
 
     config ESP_INT_WDT
         bool "Interrupt watchdog"

components/esp_common/sdkconfig.rename

@@ -8,7 +8,8 @@ CONFIG_IPC_TASK_STACK_SIZE                              CONFIG_ESP_IPC_TASK_STAC
 CONFIG_CONSOLE_UART                                     CONFIG_ESP_CONSOLE_UART
 CONFIG_CONSOLE_UART_DEFAULT                             CONFIG_ESP_CONSOLE_UART_DEFAULT
 CONFIG_CONSOLE_UART_CUSTOM                              CONFIG_ESP_CONSOLE_UART_CUSTOM
-CONFIG_CONSOLE_UART_NONE                                CONFIG_ESP_CONSOLE_UART_NONE
+CONFIG_CONSOLE_UART_NONE                                CONFIG_ESP_CONSOLE_NONE
+CONFIG_ESP_CONSOLE_UART_NONE                            CONFIG_ESP_CONSOLE_NONE
 CONFIG_CONSOLE_UART_NUM                                 CONFIG_ESP_CONSOLE_UART_NUM
 CONFIG_CONSOLE_UART_CUSTOM_NUM_0                        CONFIG_ESP_CONSOLE_UART_CUSTOM_NUM_0
 CONFIG_CONSOLE_UART_CUSTOM_NUM_1                        CONFIG_ESP_CONSOLE_UART_CUSTOM_NUM_1

components/esp_rom/CMakeLists.txt

@@ -2,7 +2,8 @@ idf_build_get_property(target IDF_TARGET)
 
 idf_component_register(SRCS "patches/esp_rom_crc.c"
                        INCLUDE_DIRS include
-                       PRIV_INCLUDE_DIRS "${target}")
+                       PRIV_INCLUDE_DIRS "${target}"
+                       PRIV_REQUIRES soc)
 
 if(BOOTLOADER_BUILD)
     set(scripts
@@ -83,3 +84,7 @@ else() # Regular app build
     target_linker_script(${COMPONENT_LIB} INTERFACE "${scripts}")
 
 endif()
+
+if(target STREQUAL "esp32s2")
+    target_sources(${COMPONENT_LIB} PRIVATE "esp32s2/usb_descriptors.c")
+endif()

components/esp_rom/esp32s2/ld/esp32s2.rom.ld

@@ -570,6 +570,11 @@ PROVIDE ( rom_txiq_set_reg = 0x4000bf64 );
 PROVIDE ( rom_tx_paon_set = 0x40009db8 );
 PROVIDE ( rom_tx_pwr_backoff = 0x4000ceb8 );
 PROVIDE ( rom_txtone_linear_pwr = 0x4000c0b0 );
+PROVIDE ( rom_usb_dev = 0x3ffffb9c );  /* static "usb_dev" */
+PROVIDE ( rom_usb_dev_end = 0x3ffffc78 );  /* end of "usb_dev" */
+PROVIDE ( rom_usb_dw_ctrl = 0x3ffffa74 );  /* static "usb_dw_ctrl" */
+PROVIDE ( rom_usb_dw_ctrl_end = 0x3ffffb9c );  /* end of "usb_dw_ctrl" */
+PROVIDE ( rom_usb_curr_desc = 0x3ffffa54 ); /* static "s_curr_descr" */
 PROVIDE ( rom_wait_rfpll_cal_end = 0x4000af3c );
 PROVIDE ( rom_wifi_11g_rate_chg = 0x4000d260 );
 PROVIDE ( rom_wifi_rifs_mode_en = 0x40009d2c );
@@ -646,7 +651,7 @@ PROVIDE ( string0_descr = 0x3ffaeeae );
 PROVIDE ( str_manu_descr = 0x3ffaee9a );
 PROVIDE ( str_prod_descr = 0x3ffaee88 );
 PROVIDE ( str_serial_descr = 0x3ffaee84 );
-PROVIDE ( s_usb_osglue = 0x3ffffcdc );
+PROVIDE ( rom_usb_osglue = 0x3ffffcdc );
 PROVIDE ( _SyscallException = 0x4000732a );
 PROVIDE ( syscall_table_ptr_pro = 0x3ffffd78 );
 PROVIDE ( tdefl_compress = 0x400041dc );

components/esp_rom/esp32s2/usb_descriptors.c

@@ -0,0 +1,75 @@
+// Copyright 2020 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <string.h>
+#include "esp32s2/rom/usb/usb_common.h"
+#include "soc/soc.h"
+#include "soc/efuse_reg.h"
+
+/* USB CDC descriptor.
+ * Note that we aren't using the one in ROM since it doesn't
+ * set "serial" to the MAC address.
+ * However overriding the descriptor is cheap - we can reuse most
+ * of its components from ROM.
+ */
+
+/* This is not const, since the MAC address is only known at run time */
+static struct string_descriptor s_str_serial_descr = {
+    .bLength = 2 + 2 * 17,
+    .bDescriptorType = 0x03,
+    .bString={'0', '0', ':', '0', '0', ':', '0', '0', ':', '0', '0', ':', '0', '0', ':', '0', '0'}
+};
+
+static const struct rom_usb_descriptors s_acm_usb_descriptors_override = {
+    .device_descr = &general_device_descr,
+    .config_descr = { &acm_config_descr },
+    .string_count = 4,
+    .string0_descr = &string0_descr,
+    .string_descrs = {
+        &str_manu_descr,
+        &str_prod_descr,
+        &s_str_serial_descr
+    }
+};
+
+static inline uint16_t nibble_to_hex_u16(uint8_t b)
+{
+    if (b < 0xa) {
+        return '0' + b;
+    } else {
+        return 'a' + b - 0xa;
+    }
+}
+
+void rom_usb_cdc_set_descriptor_patch(void)
+{
+    /* Get the MAC address */
+    const uint32_t mac0 = REG_GET_FIELD(EFUSE_RD_MAC_SPI_SYS_0_REG, EFUSE_MAC_0);
+    const uint32_t mac1 = REG_GET_FIELD(EFUSE_RD_MAC_SPI_SYS_1_REG, EFUSE_MAC_1);
+    uint8_t mac_bytes[6];
+    memcpy(mac_bytes, &mac0, 4);
+    memcpy(mac_bytes + 4, &mac1, 2);
+
+    /* Convert to UTF16 string */
+    uint16_t* dst = s_str_serial_descr.bString;
+    for (int i = 0; i < 6; ++i) {
+        uint8_t b = mac_bytes[5 - i]; /* printing from the MSB */
+        *dst++ = nibble_to_hex_u16(b >> 4);
+        *dst++ = nibble_to_hex_u16(b & 0xf);
+        dst++;
+    }
+
+    /* Override the pointer to descriptors structure */
+    rom_usb_curr_desc = &s_acm_usb_descriptors_override;
+}

components/esp_rom/include/esp32s2/rom/uart.h

@@ -162,6 +162,14 @@ typedef struct {
     int              received;
 } UartDevice;
 
+typedef enum {
+    ROM_UART_0,
+    ROM_UART_1,
+    ROM_UART_USB
+} rom_uart_num_t;
+
+#define CDC_ACM_WORK_BUF_MIN 128
+
 /**
   * @brief Init uart device struct value and reset uart0/uart1 rx.
   *        Please do not call this function in SDK.
@@ -428,7 +436,8 @@ uint8_t UartConnCheck(uint8_t uart_no);
 
 /**
   * @brief Initialize the USB ACM UART
-  * Needs to be fed a buffer of at least 128 bytes, plus any rx buffer you may want to have.
+  * Needs to be fed a buffer of at least 128 bytes (CDC_ACM_WORK_BUF_MIN),
+  * plus any rx buffer you may want to have.
   *
   * @param cdc_acm_work_mem Pointer to work mem for CDC-ACM code
   * @param cdc_acm_work_mem_len Length of work mem

components/esp_rom/include/esp32s2/rom/usb/cdc_acm.h

@@ -0,0 +1,262 @@
+/*******************************************************************************
+ *
+ * Copyright(c) 2015,2016 Intel Corporation.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ * * Neither the name of Intel Corporation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ ******************************************************************************/
+
+#pragma once
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef void cdc_acm_device;
+extern cdc_acm_device *uart_acm_dev;
+
+#define ACM_BYTES_PER_TX  64
+
+//ACM statuses are negative to distinguish from USB_DC_* status codes
+#define ACM_STATUS_LINESTATE_CHANGED -1
+#define ACM_STATUS_LINECODING_CHANGED -2
+#define ACM_STATUS_TX -3
+#define ACM_STATUS_RX -4
+
+typedef void(*uart_irq_callback_t)(cdc_acm_device *dev, int status);
+
+/**
+ * @brief Get amount of received characters in buffer
+ *
+ * @returns character count
+ */
+
+int cdc_acm_rx_fifo_cnt(cdc_acm_device *dev);
+
+
+/*
+ * @brief Poll the device for input.
+ *
+ * @return -ENOTSUP Since underlying USB device controller always uses
+ * interrupts, polled mode UART APIs are not implemented for the UART interface
+ * exported by CDC ACM driver. Apps should use fifo_read API instead.
+ */
+
+int cdc_acm_poll_in(cdc_acm_device *dev, unsigned char *c);
+
+/*
+ * @brief Output a character in polled mode.
+ *
+ * The UART poll method for USB UART is simulated by waiting till
+ * we get the next BULK In upcall from the USB device controller or 100 ms.
+ *
+ * @return the same character which is sent
+ */
+unsigned char cdc_acm_poll_out(cdc_acm_device *dev, unsigned char c);
+
+/**
+ * @brief Fill FIFO with data
+ *
+ * @param dev     CDC ACM device struct.
+ * @param tx_data Data to transmit.
+ * @param len     Number of bytes to send.
+ *
+ * @return Number of bytes sent.
+ */
+int cdc_acm_fifo_fill(cdc_acm_device *dev, const uint8_t *tx_data, int len);
+
+/**
+ * @brief Read data from FIFO
+ *
+ * @param dev     CDC ACM device struct.
+ * @param rx_data Pointer to data container.
+ * @param size    Container size.
+ *
+ * @return Number of bytes read.
+ */
+int cdc_acm_fifo_read(cdc_acm_device *dev, uint8_t *rx_data, const int size);
+
+/**
+ * @brief Enable TX interrupt
+ *
+ * @param dev CDC ACM device struct.
+ *
+ * @return N/A.
+ */
+void cdc_acm_irq_tx_enable(cdc_acm_device *dev);
+
+/**
+ * @brief Disable TX interrupt
+ *
+ * @param dev CDC ACM device struct.
+ *
+ * @return N/A.
+ */
+void cdc_acm_irq_tx_disable(cdc_acm_device *dev);
+
+/**
+ * @brief Check if Tx IRQ has been raised
+ *
+ * @param dev CDC ACM device struct.
+ *
+ * @return 1 if a Tx IRQ is pending, 0 otherwise.
+ */
+int cdc_acm_irq_tx_ready(cdc_acm_device *dev);
+
+/**
+ * @brief Enable RX interrupt
+ *
+ * @param dev CDC ACM device struct.
+ *
+ * @return N/A
+ */
+void cdc_acm_irq_rx_enable(cdc_acm_device *dev);
+
+/**
+ * @brief Disable RX interrupt
+ *
+ * @param dev CDC ACM device struct.
+ *
+ * @return N/A.
+ */
+void cdc_acm_irq_rx_disable(cdc_acm_device *dev);
+
+/**
+ * @brief Enable line state interrupt
+ *
+ * @param dev CDC ACM device struct.
+ *
+ * @return N/A.
+ */
+void cdc_acm_irq_state_enable(cdc_acm_device *dev);
+
+/**
+ * @brief Disable line state interrupt
+ *
+ * @param dev CDC ACM device struct.
+ *
+ * @return N/A.
+ */
+void cdc_acm_irq_state_disable(cdc_acm_device *dev);
+
+
+/**
+ * @brief Check if Rx IRQ has been raised
+ *
+ * @param dev CDC ACM device struct.
+ *
+ * @return 1 if an IRQ is ready, 0 otherwise.
+ */
+int cdc_acm_irq_rx_ready(cdc_acm_device *dev);
+
+/**
+ * @brief Check if Tx or Rx IRQ is pending
+ *
+ * @param dev CDC ACM device struct.
+ *
+ * @return 1 if a Tx or Rx IRQ is pending, 0 otherwise.
+ */
+int cdc_acm_irq_is_pending(cdc_acm_device *dev);
+
+/**
+ * @brief Set the callback function pointer for IRQ.
+ *
+ * @param dev CDC ACM device struct.
+ * @param cb  Callback function pointer.
+ *
+ * @return N/A
+ */
+void cdc_acm_irq_callback_set(cdc_acm_device *dev, uart_irq_callback_t cb);
+
+/**
+ * @brief Manipulate line control for UART.
+ *
+ * @param dev CDC ACM device struct
+ * @param ctrl The line control to be manipulated
+ * @param val Value to set the line control
+ *
+ * @return 0 if successful, failed otherwise.
+ */
+int cdc_acm_line_ctrl_set(cdc_acm_device *dev, uint32_t ctrl, uint32_t val);
+
+/**
+ * @brief Manipulate line control for UART.
+ *
+ * @param dev CDC ACM device struct
+ * @param ctrl The line control to be manipulated
+ * @param val Value to set the line control
+ *
+ * @return 0 if successful, failed otherwise.
+ */
+int cdc_acm_line_ctrl_get(cdc_acm_device *dev, uint32_t ctrl, uint32_t *val);
+
+
+/**
+ * @brief Initialize UART channel
+ *
+ * This routine is called to reset the chip in a quiescent state.
+ * It is assumed that this function is called only once per UART.
+ *
+ * @param mem_chunk Memory chunk to use for internal use
+ * @param mem_chunk_size Size of the memory chunk in bytes
+ *
+ * @return dev or NULL
+ */
+cdc_acm_device *cdc_acm_init(void *mem_chunk, int mem_chunk_size);
+
+
+/** Common line controls for UART.*/
+#define LINE_CTRL_BAUD_RATE (1 << 0)
+#define LINE_CTRL_RTS       (1 << 1)
+#define LINE_CTRL_DTR       (1 << 2)
+#define LINE_CTRL_DCD       (1 << 3)
+#define LINE_CTRL_DSR       (1 << 4)
+
+/* Common communication errors for UART.*/
+
+/** @brief Overrun error */
+#define UART_ERROR_OVERRUN  (1 << 0)
+
+/** @brief Parity error */
+#define UART_ERROR_PARITY   (1 << 1)
+
+/** @brief Framing error */
+#define UART_ERROR_FRAMING  (1 << 2)
+
+/**
+ * @brief Break interrupt error:
+ *
+ * A break interrupt was received. This happens when the serial input is
+ * held at a logic '0' state for longer than the sum of start time + data bits
+ * + parity + stop bits.
+ */
+#define UART_ERROR_BREAK    (1 << 3)
+
+#ifdef __cplusplus
+}
+#endif

components/esp_rom/include/esp32s2/rom/usb/chip_usb_dw_wrapper.h

@@ -0,0 +1,30 @@
+// Copyright 2019-2020 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+int chip_usb_dw_init(void);
+int chip_usb_dw_did_persist(void);
+void chip_usb_dw_prepare_persist(void);
+uint32_t chip_usb_get_persist_flags(void);
+void chip_usb_set_persist_flags(uint32_t flags);
+
+#ifdef __cplusplus
+}
+#endif

components/esp_rom/include/esp32s2/rom/usb/cpio.h

@@ -0,0 +1,180 @@
+// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+
+/**
+ * Archive to parse cpio data in the newc and crc formats. Generate a cpio archive like that by e.g.
+ * find . | cpio -o -H newc > archive.cpio
+ */
+
+#pragma once
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define CPIO_MODE_FILETYPE_MASK     0xF000
+#define CPIO_MODE_FILETYPE_SOCKET   0xC000
+#define CPIO_MODE_FILETYPE_SYMLINK  0xA000
+#define CPIO_MODE_FILETYPE_REGULAR  0x8000
+#define CPIO_MODE_FILETYPE_BLOCKDEV 0x6000
+#define CPIO_MODE_FILETYPE_DIR      0x4000
+#define CPIO_MODE_FILETYPE_CHARDEV  0x2000
+#define CPIO_MODE_FILETYPE_FIFO     0x1000
+#define CPIO_MODE_SUID              0x0800
+#define CPIO_MODE_SGID              0x0400
+#define CPIO_MODE_STICKY            0x0200
+
+typedef struct {
+    size_t filesize;
+    char *name;
+    uint32_t mode;
+    uint32_t check;
+} cpio_file_t;
+
+typedef enum {
+    CPIO_RET_MORE = 0,
+    CPIO_RET_DONE,
+    CPIO_RET_ERR
+} cpio_ret_t;
+
+typedef struct cpio_handle_data_t cpio_handle_data_t;
+typedef cpio_handle_data_t *cpio_handle_t;
+
+typedef enum {
+    CPIO_RSN_FILE_ALL = 0,
+    CPIO_RSN_FILE_INITIAL,
+    CPIO_RSN_FILE_MORE,
+    CPIO_RSN_FILE_END
+} cpio_callback_reason_t;
+
+
+/**
+ * Callback for cpio file data.
+ *
+ * This callback will be called by the library to indicate data for a file is available.
+ *
+ * For files in the cpio archive that fit entirely in the internal buffer, or when no internal
+ * buffer is available, are entirely contained in the buffer fed to cpio_feed(), this callback
+ * is only called once, with reason=CPIO_RNS_FILE_ALL. fileinfo will contain the information
+ * for that specific file (name, size, ...), buff_offset will be 0, buff_len is the file
+ * size and buff contains all the information for the file.
+ *
+ * For files that do not fit in the buffer, this callback will be called multiple times.
+ * The initial time with reason=CPIO_RSN_FILE_INITIAL, when more data is available with
+ * CPIO_RSN_FILE_MORE and finally with CPIO_RSN_FILE_END. For these calls, fileinfo
+ * will again contain file information. buff will be the information contained in the
+ * file at offset buff_offset, and the lenght of this buffer will be in buff_len.
+ *
+ * The library guarantees to feed all file data to the callback consequitively, so
+ * within the same file, the buff_offset from a call will always be (buff_offset+buff_len)
+ * from the call before that. If cpio_start is
+ *
+ * The library also guarantees every file in the cpio archive will either generate a single
+ * callback call with CPIO_RSN_ALL, or multiple with in sequence CPIO_RSN_FILE_INITIAL, 0 or
+ * more CPIO_RSN_FILE_MORE and finally a CPIO_RSN_FILE_END.
+ *
+ * When a non-zero buffer size is passed to cpio_start, the library guarantees that all callback
+ * calls with a reason of CPIO_RSN_FILE_INITIAL and CPIO_RSN_FILE_MORE will have a buffer
+ * filled with exactly this amount of bytes.
+ *
+ */
+typedef void (*cpio_callback_t)(cpio_callback_reason_t reason, cpio_file_t *fileinfo, size_t buff_offset, size_t buff_len, char *buff, void *arg);
+
+
+/**
+ * @brief      Initialize a cpio handle.
+ *
+ * Call this to start parsing a cpio archive. You can set the callback that handles the
+ * files/data here.
+ *
+ * @param  callback The callback that will handle the data of the files inside the cpio archive
+ *
+ * @param  cbarg User-supplied argument. The callback will be called with this as an argument.
+ *
+ * @param  buflen Length of internal buffer used.
+ *                If this is zero, the callback will be called with data that lives in the data buffer
+ *                supplied to the cpio library by whomever called cpio_feed(). Because this library has
+ *                no power over that buffer, the callback can be passed as little as 1 and as many as
+ *                INT_MAX bytes at a time.
+ *                If this is non-zero, the library will allocate an internal buffer of this size. All
+ *                cpio_feed()-calls will be rebuffered, and the callback is guaranteed to only be called
+ *                with this many bytes in the buffer, given there's enough data in the file to fill it.
+ *
+ * @param memchunk Chunk of memory to allocate everything (handle, I/O buffer, filename buffer) in. Minimum size
+ *                 (estimate) is 160+buflen+sizeof(largest filename/path).
+ * @param memchunklen Size of the mem chunk
+ *
+ * @return
+ *     - Success: A pointer to a cpio handle
+ *     - Error: NULL
+ *
+ */
+cpio_handle_t cpio_start(cpio_callback_t callback, void *cbarg, size_t buflen, void *memchunk, int memchunklen);
+
+/**
+ * @brief      Feed data from a cpio archive into the library
+ *
+ * This routine is used to feed consecutive data of the cpio archive into the library. While processing,
+ * the library can call the callback function one or more times if needed.
+ *
+ * @param  cpio Handle obtained by calling cpio_start()
+ *
+ * @param  buffer Pointer to buffer containing cpio archive data
+ *
+ * @param  len Length of the buffer, in bytes
+ *
+ * @return
+ *     - CPIO_RET_MORE: CPIO archive isn't done yet, please feed more data.
+ *     - CPIO_RET_DONE: CPUI archive is finished.
+ *     - CPIO_RET_ERR: Invalid CPIO archive data; decoding aborted.
+ *
+ */
+cpio_ret_t cpio_feed(cpio_handle_t cpio, char *buffer, int len);
+
+/**
+ * @brief      Indicate there is no more cpio data to be fed into the archive
+ *
+ * This call is to be called when the source data is exhausted. Normally, the library can find the end of the
+ * cpio archive by looking for the end marker,
+ *
+ * @param  timer_conf Pointer of LEDC timer configure struct
+ *
+ *
+ * @return
+ *     - CPIO_RET_DONE on success
+ *     - CPIO_RET_ERR when cpio archive is invalid
+ *
+ */
+cpio_ret_t cpio_done(cpio_handle_t cpio);
+
+
+/**
+ * @brief      Free the memory allocated for a cpio handle.
+ *
+ * @param  cpio Handle obtained by calling cpio_start()
+ *
+ * @return
+ *     - CPIO_RET_DONE on success
+ *
+ */
+cpio_ret_t cpio_destroy(cpio_handle_t cpio);
+
+#ifdef __cplusplus
+}
+#endif

components/esp_rom/include/esp32s2/rom/usb/usb_cdc.h

@@ -0,0 +1,174 @@
+/* usb_cdc.h - USB CDC-ACM and CDC-ECM public header */
+
+/*
+ * Copyright (c) 2017 PHYTEC Messtechnik GmbH
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+
+/**
+ * @file
+ * @brief USB Communications Device Class (CDC) public header
+ *
+ * Header follows the Class Definitions for
+ * Communications Devices Specification (CDC120-20101103-track.pdf),
+ * PSTN Devices Specification (PSTN120.pdf) and
+ * Ethernet Control Model Devices Specification (ECM120.pdf).
+ * Header is limited to ACM and ECM Subclasses.
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <sys/cdefs.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** CDC Specification release number in BCD format */
+#define CDC_SRN_1_20            0x0120
+
+/** Communications Class Subclass Codes */
+#define ACM_SUBCLASS            0x02
+#define ECM_SUBCLASS            0x06
+#define EEM_SUBCLASS            0x0c
+
+/** Communications Class Protocol Codes */
+#define AT_CMD_V250_PROTOCOL        0x01
+#define EEM_PROTOCOL            0x07
+
+/**
+ * @brief Data Class Interface Codes
+ * @note CDC120-20101103-track.pdf, 4.5, Table 6
+ */
+#define DATA_INTERFACE_CLASS        0x0A
+
+/**
+ * @brief Values for the bDescriptorType Field
+ * @note CDC120-20101103-track.pdf, 5.2.3, Table 12
+ */
+#define CS_INTERFACE            0x24
+#define CS_ENDPOINT         0x25
+
+/**
+ * @brief bDescriptor SubType for Communications
+ * Class Functional Descriptors
+ * @note CDC120-20101103-track.pdf, 5.2.3, Table 13
+ */
+#define HEADER_FUNC_DESC        0x00
+#define CALL_MANAGEMENT_FUNC_DESC   0x01
+#define ACM_FUNC_DESC           0x02
+#define UNION_FUNC_DESC         0x06
+#define ETHERNET_FUNC_DESC      0x0F
+
+/**
+ * @brief PSTN Subclass Specific Requests
+ * for ACM devices
+ * @note PSTN120.pdf, 6.3, Table 13
+ */
+#define CDC_SEND_ENC_CMD        0x00
+#define CDC_GET_ENC_RSP         0x01
+#define SET_LINE_CODING         0x20
+#define GET_LINE_CODING         0x21
+#define SET_CONTROL_LINE_STATE      0x22
+
+/** Control Signal Bitmap Values for SetControlLineState */
+#define SET_CONTROL_LINE_STATE_RTS  0x02
+#define SET_CONTROL_LINE_STATE_DTR  0x01
+
+/** UART State Bitmap Values */
+#define SERIAL_STATE_OVERRUN        0x40
+#define SERIAL_STATE_PARITY     0x20
+#define SERIAL_STATE_FRAMING        0x10
+#define SERIAL_STATE_RING       0x08
+#define SERIAL_STATE_BREAK      0x04
+#define SERIAL_STATE_TX_CARRIER     0x02
+#define SERIAL_STATE_RX_CARRIER     0x01
+
+/**
+ * @brief Class-Specific Request Codes for Ethernet subclass
+ * @note ECM120.pdf, 6.2, Table 6
+ */
+#define SET_ETHERNET_MULTICAST_FILTERS  0x40
+#define SET_ETHERNET_PM_FILTER      0x41
+#define GET_ETHERNET_PM_FILTER      0x42
+#define SET_ETHERNET_PACKET_FILTER  0x43
+#define GET_ETHERNET_STATISTIC      0x44
+
+/** Ethernet Packet Filter Bitmap */
+#define PACKET_TYPE_MULTICAST       0x10
+#define PACKET_TYPE_BROADCAST       0x08
+#define PACKET_TYPE_DIRECTED        0x04
+#define PACKET_TYPE_ALL_MULTICAST   0x02
+#define PACKET_TYPE_PROMISCUOUS     0x01
+
+/** Header Functional Descriptor */
+struct cdc_header_descriptor {
+    uint8_t bFunctionLength;
+    uint8_t bDescriptorType;
+    uint8_t bDescriptorSubtype;
+    uint16_t bcdCDC;
+} __packed;
+
+/** Union Interface Functional Descriptor */
+struct cdc_union_descriptor {
+    uint8_t bFunctionLength;
+    uint8_t bDescriptorType;
+    uint8_t bDescriptorSubtype;
+    uint8_t bControlInterface;
+    uint8_t bSubordinateInterface0;
+} __packed;
+
+/** Call Management Functional Descriptor */
+struct cdc_cm_descriptor {
+    uint8_t bFunctionLength;
+    uint8_t bDescriptorType;
+    uint8_t bDescriptorSubtype;
+    uint8_t bmCapabilities;
+    uint8_t bDataInterface;
+} __packed;
+
+/** Abstract Control Management Functional Descriptor */
+struct cdc_acm_descriptor {
+    uint8_t bFunctionLength;
+    uint8_t bDescriptorType;
+    uint8_t bDescriptorSubtype;
+    uint8_t bmCapabilities;
+} __packed;
+
+
+/** Data structure for GET_LINE_CODING / SET_LINE_CODING class requests */
+struct cdc_acm_line_coding {
+    uint32_t dwDTERate;
+    uint8_t bCharFormat;
+    uint8_t bParityType;
+    uint8_t bDataBits;
+} __packed;
+
+/** Data structure for the notification about SerialState */
+struct cdc_acm_notification {
+    uint8_t bmRequestType;
+    uint8_t bNotificationType;
+    uint16_t wValue;
+    uint16_t wIndex;
+    uint16_t wLength;
+    uint16_t data;
+} __packed;
+
+/** Ethernet Networking Functional Descriptor */
+struct cdc_ecm_descriptor {
+    uint8_t bFunctionLength;
+    uint8_t bDescriptorType;
+    uint8_t bDescriptorSubtype;
+    uint8_t iMACAddress;
+    uint32_t bmEthernetStatistics;
+    uint16_t wMaxSegmentSize;
+    uint16_t wNumberMCFilters;
+    uint8_t bNumberPowerFilters;
+} __packed;
+
+#ifdef __cplusplus
+}
+#endif

components/esp_rom/include/esp32s2/rom/usb/usb_common.h

@@ -0,0 +1,249 @@
+/***************************************************************************
+ *
+ *
+ * Copyright(c) 2015,2016 Intel Corporation.
+ * Copyright(c) 2017 PHYTEC Messtechnik GmbH
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ * * Neither the name of Intel Corporation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ ***************************************************************************/
+
+/**
+ * @file
+ * @brief useful constants and macros for the USB application
+ *
+ * This file contains useful constants and macros for the USB applications.
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <sys/cdefs.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define BCD(x) ((((x) / 10) << 4) | ((x) / 10))
+
+/* Descriptor size in bytes */
+#define USB_DEVICE_DESC_SIZE        18
+#define USB_CONFIGURATION_DESC_SIZE 9
+#define USB_INTERFACE_DESC_SIZE     9
+#define USB_ENDPOINT_DESC_SIZE      7
+#define USB_STRING_DESC_SIZE        4
+#define USB_HID_DESC_SIZE       9
+#define USB_DFU_DESC_SIZE       9
+#define USB_DEVICE_QUAL_DESC_SIZE   10
+#define USB_INTERFACE_ASSOC_DESC_SIZE   8
+
+/* Descriptor type */
+#define USB_DEVICE_DESC         0x01
+#define USB_CONFIGURATION_DESC      0x02
+#define USB_STRING_DESC         0x03
+#define USB_INTERFACE_DESC      0x04
+#define USB_ENDPOINT_DESC       0x05
+#define USB_DEVICE_QUAL_DESC        0x06
+#define USB_INTERFACE_ASSOC_DESC    0x0B
+#define USB_DEVICE_CAPABILITY_DESC  0x10
+#define USB_HID_DESC            0x21
+#define USB_HID_REPORT_DESC     0x22
+#define USB_DFU_FUNCTIONAL_DESC     0x21
+#define USB_ASSOCIATION_DESC        0x0B
+#define USB_BINARY_OBJECT_STORE_DESC    0x0F
+
+/* Useful define */
+#define USB_1_1             0x0110
+#define USB_2_0             0x0200
+/* Set USB version to 2.1 so that the host will request the BOS descriptor */
+#define USB_2_1             0x0210
+
+#define BCDDEVICE_RELNUM        (BCD(KERNEL_VERSION_MAJOR) << 8 | \
+                    BCD(KERNEL_VERSION_MINOR))
+
+/* 100mA max power, per 2mA units */
+/* USB 1.1 spec indicates 100mA(max) per unit load, up to 5 loads */
+#define MAX_LOW_POWER           0x32
+#define MAX_HIGH_POWER          0xFA
+
+/* bmAttributes:
+ * D7:Reserved, always 1,
+ * D6:Self-Powered -> 1,
+ * D5:Remote Wakeup -> 0,
+ * D4...0:Reserved -> 0
+ */
+#define USB_CONFIGURATION_ATTRIBUTES    0xC0
+
+/* Classes */
+#define COMMUNICATION_DEVICE_CLASS  0x02
+#define COMMUNICATION_DEVICE_CLASS_DATA 0x0A
+#define HID_CLASS           0x03
+#define MASS_STORAGE_CLASS      0x08
+#define WIRELESS_DEVICE_CLASS       0xE0
+#define MISC_CLASS          0xEF
+#define CUSTOM_CLASS            0xFF
+#define DFU_DEVICE_CLASS        0xFE
+
+/* Sub-classes */
+#define CDC_NCM_SUBCLASS        0x0d
+#define BOOT_INTERFACE_SUBCLASS     0x01
+#define SCSI_TRANSPARENT_SUBCLASS   0x06
+#define DFU_INTERFACE_SUBCLASS      0x01
+#define RF_SUBCLASS         0x01
+#define CUSTOM_SUBCLASS         0xFF
+#define COMMON_SUBCLASS         0x02
+/* Misc subclasses */
+#define MISC_RNDIS_SUBCLASS     0x04
+#define CDC_ABSTRACT_CONTROL_MODEL 0x02
+
+/* Protocols */
+#define V25TER_PROTOCOL         0x01
+#define MOUSE_PROTOCOL          0x02
+#define BULK_ONLY_PROTOCOL      0x50
+#define DFU_RUNTIME_PROTOCOL        0x01
+#define DFU_MODE_PROTOCOL       0x02
+#define BLUETOOTH_PROTOCOL      0x01
+/* CDC ACM protocols */
+#define ACM_VENDOR_PROTOCOL     0xFF
+/* Misc protocols */
+#define MISC_ETHERNET_PROTOCOL      0x01
+#define IAD_PROTOCOL            0x01
+
+/** Standard Device Descriptor */
+struct usb_device_descriptor {
+    uint8_t bLength;
+    uint8_t bDescriptorType;
+    uint16_t bcdUSB;
+    uint8_t bDeviceClass;
+    uint8_t bDeviceSubClass;
+    uint8_t bDeviceProtocol;
+    uint8_t bMaxPacketSize0;
+    uint16_t idVendor;
+    uint16_t idProduct;
+    uint16_t bcdDevice;
+    uint8_t iManufacturer;
+    uint8_t iProduct;
+    uint8_t iSerialNumber;
+    uint8_t bNumConfigurations;
+} __packed;
+
+/** Unicode (UTF16LE) String Descriptor */
+struct usb_string_descriptor {
+    uint8_t bLength;
+    uint8_t bDescriptorType;
+    uint16_t bString;
+} __packed;
+
+/** Association Descriptor */
+struct usb_association_descriptor {
+    uint8_t bLength;
+    uint8_t bDescriptorType;
+    uint8_t bFirstInterface;
+    uint8_t bInterfaceCount;
+    uint8_t bFunctionClass;
+    uint8_t bFunctionSubClass;
+    uint8_t bFunctionProtocol;
+    uint8_t iFunction;
+} __packed;
+
+/** Standard Configuration Descriptor */
+struct usb_cfg_descriptor {
+    uint8_t bLength;
+    uint8_t bDescriptorType;
+    uint16_t wTotalLength;
+    uint8_t bNumInterfaces;
+    uint8_t bConfigurationValue;
+    uint8_t iConfiguration;
+    uint8_t bmAttributes;
+    uint8_t bMaxPower;
+} __packed;
+
+/** Standard Interface Descriptor */
+struct usb_if_descriptor {
+    uint8_t bLength;
+    uint8_t bDescriptorType;
+    uint8_t bInterfaceNumber;
+    uint8_t bAlternateSetting;
+    uint8_t bNumEndpoints;
+    uint8_t bInterfaceClass;
+    uint8_t bInterfaceSubClass;
+    uint8_t bInterfaceProtocol;
+    uint8_t iInterface;
+} __packed;
+
+/** Standard Endpoint Descriptor */
+struct usb_ep_descriptor {
+    uint8_t bLength;
+    uint8_t bDescriptorType;
+    uint8_t bEndpointAddress;
+    uint8_t bmAttributes;
+    uint16_t wMaxPacketSize;
+    uint8_t bInterval;
+} __packed;
+
+struct string_descriptor_zero {
+    uint8_t bLength;
+    uint8_t bDescriptorType;
+    uint16_t wBcdLang[];
+} __packed;
+
+struct string_descriptor {
+    uint8_t bLength;
+    uint8_t bDescriptorType;
+    uint16_t bString[];
+} __packed;
+
+#define ROM_MAX_CFG_DESC_CNT 1
+
+struct rom_usb_descriptors {
+    const struct usb_device_descriptor *device_descr;
+    const void *config_descr[ROM_MAX_CFG_DESC_CNT];
+    int string_count; // including string_descriptor_zero
+    const struct string_descriptor_zero *string0_descr;
+    const struct string_descriptor *string_descrs[];
+};
+
+/* Descriptors defined in the ROM */
+extern struct usb_device_descriptor general_device_descr;
+extern const void* acm_config_descr;
+extern const void* dfu_config_descr;
+extern const struct string_descriptor str_manu_descr;
+extern const struct string_descriptor str_prod_descr;
+extern const struct string_descriptor_zero string0_descr;
+extern const struct rom_usb_descriptors acm_usb_descriptors;
+extern const struct rom_usb_descriptors dfu_usb_descriptors;
+extern const struct rom_usb_descriptors *rom_usb_curr_desc;
+
+/* ROM patch: set the ACM descriptor with the correct serial number.
+ * Only needed on ESP32-S2, on later chips the ROM descriptor is correct.
+ */
+void rom_usb_cdc_set_descriptor_patch(void);
+
+
+#ifdef __cplusplus
+}
+#endif

components/esp_rom/include/esp32s2/rom/usb/usb_dc.h

@@ -0,0 +1,392 @@
+/* usb_dc.h - USB device controller driver interface */
+
+/*
+ * Copyright (c) 2016 Intel Corporation.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @file
+ * @brief USB device controller APIs
+ *
+ * This file contains the USB device controller APIs. All device controller
+ * drivers should implement the APIs described in this file.
+ */
+
+#pragma once
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * USB endpoint direction and number.
+ */
+
+#define USB_EP_DIR_MASK 0x80
+#define USB_EP_DIR_IN   0x80
+#define USB_EP_DIR_OUT  0x00
+
+/**
+ * USB Driver Status Codes
+ */
+enum usb_dc_status_code {
+    USB_DC_ERROR,        /* USB error reported by the controller */
+    USB_DC_RESET,        /* USB reset */
+    /* USB connection established, hardware enumeration is completed */
+    USB_DC_CONNECTED,
+    USB_DC_CONFIGURED,   /* USB configuration done */
+    USB_DC_DISCONNECTED, /* USB connection lost */
+    USB_DC_SUSPEND,      /* USB connection suspended by the HOST */
+    USB_DC_RESUME,       /* USB connection resumed by the HOST */
+    USB_DC_INTERFACE,    /* USB interface selected */
+    USB_DC_SET_HALT,     /* Set Feature ENDPOINT_HALT received */
+    USB_DC_CLEAR_HALT,   /* Clear Feature ENDPOINT_HALT received */
+    USB_DC_UNKNOWN       /* Initial USB connection status */
+};
+
+/**
+ * USB Endpoint Callback Status Codes
+ */
+enum usb_dc_ep_cb_status_code {
+    USB_DC_EP_SETUP,    /* SETUP received */
+    /* Out transaction on this EP, data is available for read */
+    USB_DC_EP_DATA_OUT,
+    USB_DC_EP_DATA_IN,  /* In transaction done on this EP */
+};
+
+/**
+ * USB Endpoint type
+ */
+enum usb_dc_ep_type {
+    USB_DC_EP_CONTROL = 0,  /* Control type endpoint */
+    USB_DC_EP_ISOCHRONOUS,  /* Isochronous type endpoint */
+    USB_DC_EP_BULK,         /* Bulk type endpoint */
+    USB_DC_EP_INTERRUPT     /* Interrupt type endpoint  */
+};
+
+/**
+ * USB Endpoint Configuration.
+ */
+struct usb_dc_ep_cfg_data {
+    /** The number associated with the EP in the device
+     *  configuration structure
+     *       IN  EP = 0x80 | \<endpoint number\>
+     *       OUT EP = 0x00 | \<endpoint number\>
+     */
+    uint8_t ep_addr;
+    uint16_t ep_mps;             /** Endpoint max packet size */
+    enum usb_dc_ep_type ep_type; /** Endpoint type */
+};
+
+/**
+ * Callback function signature for the USB Endpoint status
+ */
+typedef void (*usb_dc_ep_callback)(uint8_t ep,
+                                   enum usb_dc_ep_cb_status_code cb_status);
+
+/**
+ * Callback function signature for the device
+ */
+typedef void (*usb_dc_status_callback)(enum usb_dc_status_code cb_status,
+                                       uint8_t *param);
+
+/**
+ * @brief attach USB for device connection
+ *
+ * Function to attach USB for device connection. Upon success, the USB PLL
+ * is enabled, and the USB device is now capable of transmitting and receiving
+ * on the USB bus and of generating interrupts.
+ *
+ * @return 0 on success, negative errno code on fail.
+ */
+int usb_dc_attach(void);
+
+/**
+ * @brief detach the USB device
+ *
+ * Function to detach the USB device. Upon success, the USB hardware PLL
+ * is powered down and USB communication is disabled.
+ *
+ * @return 0 on success, negative errno code on fail.
+ */
+int usb_dc_detach(void);
+
+/**
+ * @brief reset the USB device
+ *
+ * This function returns the USB device and firmware back to it's initial state.
+ * N.B. the USB PLL is handled by the usb_detach function
+ *
+ * @return 0 on success, negative errno code on fail.
+ */
+int usb_dc_reset(void);
+
+/**
+ * @brief set USB device address
+ *
+ * @param[in] addr device address
+ *
+ * @return 0 on success, negative errno code on fail.
+ */
+int usb_dc_set_address(const uint8_t addr);
+
+/**
+ * @brief set USB device controller status callback
+ *
+ * Function to set USB device controller status callback. The registered
+ * callback is used to report changes in the status of the device controller.
+ *
+ * @param[in] cb callback function
+ *
+ * @return 0 on success, negative errno code on fail.
+ */
+int usb_dc_set_status_callback(const usb_dc_status_callback cb);
+
+/**
+ * @brief check endpoint capabilities
+ *
+ * Function to check capabilities of an endpoint. usb_dc_ep_cfg_data structure
+ * provides the endpoint configuration parameters: endpoint address,
+ * endpoint maximum packet size and endpoint type.
+ * The driver should check endpoint capabilities and return 0 if the
+ * endpoint configuration is possible.
+ *
+ * @param[in] cfg Endpoint config
+ *
+ * @return 0 on success, negative errno code on fail.
+ */
+int usb_dc_ep_check_cap(const struct usb_dc_ep_cfg_data *const cfg);
+
+/**
+ * @brief configure endpoint
+ *
+ * Function to configure an endpoint. usb_dc_ep_cfg_data structure provides
+ * the endpoint configuration parameters: endpoint address, endpoint maximum
+ * packet size and endpoint type.
+ *
+ * @param[in] cfg Endpoint config
+ *
+ * @return 0 on success, negative errno code on fail.
+ */
+int usb_dc_ep_configure(const struct usb_dc_ep_cfg_data *const cfg);
+
+/**
+ * @brief set stall condition for the selected endpoint
+ *
+ * @param[in] ep Endpoint address corresponding to the one
+ *               listed in the device configuration table
+ *
+ * @return 0 on success, negative errno code on fail.
+ */
+int usb_dc_ep_set_stall(const uint8_t ep);
+
+/**
+ * @brief clear stall condition for the selected endpoint
+ *
+ * @param[in] ep Endpoint address corresponding to the one
+ *               listed in the device configuration table
+ *
+ * @return 0 on success, negative errno code on fail.
+ */
+int usb_dc_ep_clear_stall(const uint8_t ep);
+
+/**
+ * @brief check if selected endpoint is stalled
+ *
+ * @param[in]  ep       Endpoint address corresponding to the one
+ *                      listed in the device configuration table
+ * @param[out] stalled  Endpoint stall status
+ *
+ * @return 0 on success, negative errno code on fail.
+ */
+int usb_dc_ep_is_stalled(const uint8_t ep, uint8_t *const stalled);
+
+/**
+ * @brief halt the selected endpoint
+ *
+ * @param[in] ep Endpoint address corresponding to the one
+ *               listed in the device configuration table
+ *
+ * @return 0 on success, negative errno code on fail.
+ */
+int usb_dc_ep_halt(const uint8_t ep);
+
+/**
+ * @brief enable the selected endpoint
+ *
+ * Function to enable the selected endpoint. Upon success interrupts are
+ * enabled for the corresponding endpoint and the endpoint is ready for
+ * transmitting/receiving data.
+ *
+ * @param[in] ep Endpoint address corresponding to the one
+ *               listed in the device configuration table
+ *
+ * @return 0 on success, negative errno code on fail.
+ */
+int usb_dc_ep_enable(const uint8_t ep);
+
+/**
+ * @brief disable the selected endpoint
+ *
+ * Function to disable the selected endpoint. Upon success interrupts are
+ * disabled for the corresponding endpoint and the endpoint is no longer able
+ * for transmitting/receiving data.
+ *
+ * @param[in] ep Endpoint address corresponding to the one
+ *               listed in the device configuration table
+ *
+ * @return 0 on success, negative errno code on fail.
+ */
+int usb_dc_ep_disable(const uint8_t ep);
+
+/**
+ * @brief flush the selected endpoint
+ *
+ * @param[in] ep Endpoint address corresponding to the one
+ *               listed in the device configuration table
+ *
+ * @return 0 on success, negative errno code on fail.
+ */
+int usb_dc_ep_flush(const uint8_t ep);
+
+/**
+ * @brief write data to the specified endpoint
+ *
+ * This function is called to write data to the specified endpoint. The supplied
+ * usb_ep_callback function will be called when data is transmitted out.
+ *
+ * @param[in]  ep        Endpoint address corresponding to the one
+ *                       listed in the device configuration table
+ * @param[in]  data      pointer to data to write
+ * @param[in]  data_len  length of data requested to write. This may
+ *                       be zero for a zero length status packet.
+ * @param[out] ret_bytes bytes scheduled for transmission. This value
+ *                       may be NULL if the application expects all
+ *                       bytes to be written
+ *
+ * @return 0 on success, negative errno code on fail.
+ */
+int usb_dc_ep_write(const uint8_t ep, const uint8_t *const data,
+                    const uint32_t data_len, uint32_t *const ret_bytes);
+
+
+
+/**
+ * @brief Indicate if the write to an IN endpoint (using usb_dc_ep_write) would block
+ * to wait until the endpoint has enoug space
+ *
+ * @param[in]  ep        Endpoint address corresponding to the one
+ *                       listed in the device configuration table
+ *
+ * @return 0 when writable, 0 when not, negative errno code on fail.
+ */
+int usb_dc_ep_write_would_block(const uint8_t ep);
+
+
+/**
+ * @brief read data from the specified endpoint
+ *
+ * This function is called by the Endpoint handler function, after an OUT
+ * interrupt has been received for that EP. The application must only call this
+ * function through the supplied usb_ep_callback function. This function clears
+ * the ENDPOINT NAK, if all data in the endpoint FIFO has been read,
+ * so as to accept more data from host.
+ *
+ * @param[in]  ep           Endpoint address corresponding to the one
+ *                          listed in the device configuration table
+ * @param[in]  data         pointer to data buffer to write to
+ * @param[in]  max_data_len max length of data to read
+ * @param[out] read_bytes   Number of bytes read. If data is NULL and
+ *                          max_data_len is 0 the number of bytes
+ *                          available for read should be returned.
+ *
+ * @return 0 on success, negative errno code on fail.
+ */
+int usb_dc_ep_read(const uint8_t ep, uint8_t *const data,
+                   const uint32_t max_data_len, uint32_t *const read_bytes);
+
+/**
+ * @brief set callback function for the specified endpoint
+ *
+ * Function to set callback function for notification of data received and
+ * available to application or transmit done on the selected endpoint,
+ * NULL if callback not required by application code.
+ *
+ * @param[in] ep Endpoint address corresponding to the one
+ *               listed in the device configuration table
+ * @param[in] cb callback function
+ *
+ * @return 0 on success, negative errno code on fail.
+ */
+int usb_dc_ep_set_callback(const uint8_t ep, const usb_dc_ep_callback cb);
+
+/**
+ * @brief read data from the specified endpoint
+ *
+ * This is similar to usb_dc_ep_read, the difference being that, it doesn't
+ * clear the endpoint NAKs so that the consumer is not bogged down by further
+ * upcalls till he is done with the processing of the data. The caller should
+ * reactivate ep by invoking usb_dc_ep_read_continue() do so.
+ *
+ * @param[in]  ep           Endpoint address corresponding to the one
+ *                          listed in the device configuration table
+ * @param[in]  data         pointer to data buffer to write to
+ * @param[in]  max_data_len max length of data to read
+ * @param[out] read_bytes   Number of bytes read. If data is NULL and
+ *                          max_data_len is 0 the number of bytes
+ *                          available for read should be returned.
+ *
+ * @return 0 on success, negative errno code on fail.
+ */
+int usb_dc_ep_read_wait(uint8_t ep, uint8_t *data, uint32_t max_data_len,
+                        uint32_t *read_bytes);
+
+
+/**
+ * @brief Continue reading data from the endpoint
+ *
+ * Clear the endpoint NAK and enable the endpoint to accept more data
+ * from the host. Usually called after usb_dc_ep_read_wait() when the consumer
+ * is fine to accept more data. Thus these calls together acts as flow control
+ * mechanism.
+ *
+ * @param[in]  ep           Endpoint address corresponding to the one
+ *                          listed in the device configuration table
+ *
+ * @return 0 on success, negative errno code on fail.
+ */
+int usb_dc_ep_read_continue(uint8_t ep);
+
+/**
+ * @brief Get endpoint max packet size
+ *
+ * @param[in]  ep           Endpoint address corresponding to the one
+ *                          listed in the device configuration table
+ *
+ * @return enpoint max packet size (mps)
+ */
+int usb_dc_ep_mps(uint8_t ep);
+
+
+
+//Hack - fake interrupts by pollinfg
+void usb_dc_check_poll_for_interrupts(void);
+
+
+//Prepare for USB persist. You should reboot after this.
+int usb_dc_prepare_persist(void);
+
+
+void usb_dw_isr_handler(void);
+
+
+int usb_dc_ep_write_would_block(const uint8_t ep);
+
+
+#ifdef __cplusplus
+}
+#endif

components/esp_rom/include/esp32s2/rom/usb/usb_descriptor.h

@@ -0,0 +1,34 @@
+// Copyright 2019-2020 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define USB_DESCRIPTOR_TYPE_ACM 0
+#define USB_DESCRIPTOR_TYPE_DFU 1
+
+void usb_set_current_descriptor(int descriptor_type);
+
+bool usb_get_descriptor(uint16_t type_index, uint16_t lang_id,
+                        int32_t *len, uint8_t **data);
+
+#ifdef __cplusplus
+}
+#endif

components/esp_rom/include/esp32s2/rom/usb/usb_device.h

@@ -0,0 +1,402 @@
+/*
+ *  LPCUSB, an USB device driver for LPC microcontrollers
+ *  Copyright (C) 2006 Bertrik Sikken (bertrik@sikken.nl)
+ *  Copyright (c) 2016 Intel Corporation
+ *
+ *  Redistribution and use in source and binary forms, with or without
+ *  modification, are permitted provided that the following conditions are met:
+ *
+ *  1. Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *  2. Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *  3. The name of the author may not be used to endorse or promote products
+ *     derived from this software without specific prior written permission.
+ *
+ *  THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ *  IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ *  OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ *  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ *  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/**
+ * @file
+ * @brief USB device core layer APIs and structures
+ *
+ * This file contains the USB device core layer APIs and structures.
+ */
+
+#pragma once
+
+#include <stddef.h>
+#include <sys/cdefs.h>
+#include "usb_dc.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*************************************************************************
+ *  USB configuration
+ **************************************************************************/
+
+#define MAX_PACKET_SIZE0    64        /**< maximum packet size for EP 0 */
+//Note: for FS this should be 8, 16, 32, 64 bytes. HS can go up to 512.
+
+/*************************************************************************
+ *  USB application interface
+ **************************************************************************/
+
+/** setup packet definitions */
+struct usb_setup_packet {
+    uint8_t bmRequestType;  /**< characteristics of the specific request */
+    uint8_t bRequest;       /**< specific request */
+    uint16_t wValue;        /**< request specific parameter */
+    uint16_t wIndex;        /**< request specific parameter */
+    uint16_t wLength;       /**< length of data transferred in data phase */
+} __packed;
+
+
+_Static_assert(sizeof(struct usb_setup_packet) == 8, "USB setup packet struct size error");
+
+/**
+ * Callback function signature for the device
+ */
+typedef void (*usb_status_callback)(enum usb_dc_status_code status_code,
+                                    uint8_t *param);
+
+/**
+ * Callback function signature for the USB Endpoint status
+ */
+typedef void (*usb_ep_callback)(uint8_t ep,
+                                enum usb_dc_ep_cb_status_code cb_status);
+
+/**
+ * Function which handles Class specific requests corresponding to an
+ * interface number specified in the device descriptor table
+ */
+typedef int (*usb_request_handler) (struct usb_setup_packet *detup,
+                                    int32_t *transfer_len, uint8_t **payload_data);
+
+/**
+ * Function for interface runtime configuration
+ */
+typedef void (*usb_interface_config)(uint8_t bInterfaceNumber);
+
+/*
+ * USB Endpoint Configuration
+ */
+struct usb_ep_cfg_data {
+    /**
+     * Callback function for notification of data received and
+     * available to application or transmit done, NULL if callback
+     * not required by application code
+     */
+    usb_ep_callback ep_cb;
+    /**
+     * The number associated with the EP in the device configuration
+     * structure
+     *   IN  EP = 0x80 | \<endpoint number\>
+     *   OUT EP = 0x00 | \<endpoint number\>
+     */
+    uint8_t ep_addr;
+};
+
+/**
+ * USB Interface Configuration
+ */
+struct usb_interface_cfg_data {
+    /** Handler for USB Class specific Control (EP 0) communications */
+    usb_request_handler class_handler;
+    /** Handler for USB Vendor specific commands */
+    usb_request_handler vendor_handler;
+    /**
+     * The custom request handler gets a first chance at handling
+     * the request before it is handed over to the 'chapter 9' request
+     * handler
+     */
+    usb_request_handler custom_handler;
+    /**
+     * This data area, allocated by the application, is used to store
+     * Class specific command data and must be large enough to store the
+     * largest payload associated with the largest supported Class'
+     * command set. This data area may be used for USB IN or OUT
+     * communications
+     */
+    uint8_t *payload_data;
+    /**
+     * This data area, allocated by the application, is used to store
+     * Vendor specific payload
+     */
+    uint8_t *vendor_data;
+};
+
+/*
+ * @brief USB device configuration
+ *
+ * The Application instantiates this with given parameters added
+ * using the "usb_set_config" function. Once this function is called
+ * changes to this structure will result in undefined behaviour. This structure
+ * may only be updated after calls to usb_deconfig
+ */
+struct usb_cfg_data {
+    /**
+     * USB device description, see
+     * http://www.beyondlogic.org/usbnutshell/usb5.shtml#DeviceDescriptors
+     */
+    const uint8_t *usb_device_description;
+    /** Pointer to interface descriptor */
+    const void *interface_descriptor;
+    /** Function for interface runtime configuration */
+    usb_interface_config interface_config;
+    /** Callback to be notified on USB connection status change */
+    usb_status_callback cb_usb_status;
+    /** USB interface (Class) handler and storage space */
+    struct usb_interface_cfg_data interface;
+    /** Number of individual endpoints in the device configuration */
+    uint8_t num_endpoints;
+    /**
+     * Pointer to an array of endpoint structs of length equal to the
+     * number of EP associated with the device description,
+     * not including control endpoints
+     */
+    struct usb_ep_cfg_data *endpoint;
+};
+
+/*
+ * @brief configure USB controller
+ *
+ * Function to configure USB controller.
+ * Configuration parameters must be valid or an error is returned
+ *
+ * @param[in] config Pointer to configuration structure
+ *
+ * @return 0 on success, negative errno code on fail
+ */
+int usb_set_config(struct usb_cfg_data *config);
+
+/*
+ * @brief return the USB device to it's initial state
+ *
+ * @return 0 on success, negative errno code on fail
+ */
+int usb_deconfig(void);
+
+/*
+ * @brief enable USB for host/device connection
+ *
+ * Function to enable USB for host/device connection.
+ * Upon success, the USB module is no longer clock gated in hardware,
+ * it is now capable of transmitting and receiving on the USB bus and
+ * of generating interrupts.
+ *
+ * @return 0 on success, negative errno code on fail.
+ */
+int usb_enable(struct usb_cfg_data *config);
+
+/*
+ * @brief disable the USB device.
+ *
+ * Function to disable the USB device.
+ * Upon success, the specified USB interface is clock gated in hardware,
+ * it is no longer capable of generating interrupts.
+ *
+ * @return 0 on success, negative errno code on fail
+ */
+int usb_disable(void);
+
+/*
+ * @brief Check if a write to an in ep would block until there is enough space
+ * in the fifo
+ *
+ * @param[in]  ep        Endpoint address corresponding to the one listed in the
+ *                       device configuration table
+ *
+ * @return 0 if free to write, 1 if a write would block, negative errno code on fail
+ */
+int usb_write_would_block(uint8_t ep);
+
+/*
+ * @brief write data to the specified endpoint
+ *
+ * Function to write data to the specified endpoint. The supplied
+ * usb_ep_callback will be called when transmission is done.
+ *
+ * @param[in]  ep        Endpoint address corresponding to the one listed in the
+ *                       device configuration table
+ * @param[in]  data      Pointer to data to write
+ * @param[in]  data_len  Length of data requested to write. This may be zero for
+ *                       a zero length status packet.
+ * @param[out] bytes_ret Bytes written to the EP FIFO. This value may be NULL if
+ *                       the application expects all bytes to be written
+ *
+ * @return 0 on success, negative errno code on fail
+ */
+int usb_write(uint8_t ep, const uint8_t *data, uint32_t data_len,
+              uint32_t *bytes_ret);
+
+/*
+ * @brief read data from the specified endpoint
+ *
+ * This function is called by the Endpoint handler function, after an
+ * OUT interrupt has been received for that EP. The application must
+ * only call this function through the supplied usb_ep_callback function.
+ *
+ * @param[in]  ep           Endpoint address corresponding to the one listed in
+ *                          the device configuration table
+ * @param[in]  data         Pointer to data buffer to write to
+ * @param[in]  max_data_len Max length of data to read
+ * @param[out] ret_bytes    Number of bytes read. If data is NULL and
+ *                          max_data_len is 0 the number of bytes available
+ *                          for read is returned.
+ *
+ * @return  0 on success, negative errno code on fail
+ */
+int usb_read(uint8_t ep, uint8_t *data, uint32_t max_data_len,
+             uint32_t *ret_bytes);
+
+/*
+ * @brief set STALL condition on the specified endpoint
+ *
+ * This function is called by USB device class handler code to set stall
+ * conditionin on endpoint.
+ *
+ * @param[in]  ep           Endpoint address corresponding to the one listed in
+ *                          the device configuration table
+ *
+ * @return  0 on success, negative errno code on fail
+ */
+int usb_ep_set_stall(uint8_t ep);
+
+
+/*
+ * @brief clears STALL condition on the specified endpoint
+ *
+ * This function is called by USB device class handler code to clear stall
+ * conditionin on endpoint.
+ *
+ * @param[in]  ep           Endpoint address corresponding to the one listed in
+ *                          the device configuration table
+ *
+ * @return  0 on success, negative errno code on fail
+ */
+int usb_ep_clear_stall(uint8_t ep);
+
+/**
+ * @brief read data from the specified endpoint
+ *
+ * This is similar to usb_ep_read, the difference being that, it doesn't
+ * clear the endpoint NAKs so that the consumer is not bogged down by further
+ * upcalls till he is done with the processing of the data. The caller should
+ * reactivate ep by invoking usb_ep_read_continue() do so.
+ *
+ * @param[in]  ep           Endpoint address corresponding to the one
+ *                          listed in the device configuration table
+ * @param[in]  data         pointer to data buffer to write to
+ * @param[in]  max_data_len max length of data to read
+ * @param[out] read_bytes   Number of bytes read. If data is NULL and
+ *                          max_data_len is 0 the number of bytes
+ *                          available for read should be returned.
+ *
+ * @return 0 on success, negative errno code on fail.
+ */
+int usb_ep_read_wait(uint8_t ep, uint8_t *data, uint32_t max_data_len,
+                     uint32_t *read_bytes);
+
+
+/**
+ * @brief Continue reading data from the endpoint
+ *
+ * Clear the endpoint NAK and enable the endpoint to accept more data
+ * from the host. Usually called after usb_ep_read_wait() when the consumer
+ * is fine to accept more data. Thus these calls together acts as flow control
+ * mechanism.
+ *
+ * @param[in]  ep           Endpoint address corresponding to the one
+ *                          listed in the device configuration table
+ *
+ * @return 0 on success, negative errno code on fail.
+ */
+int usb_ep_read_continue(uint8_t ep);
+
+/**
+ * Callback function signature for transfer completion.
+ */
+typedef void (*usb_transfer_callback)(uint8_t ep, int tsize, void *priv);
+
+/* USB transfer flags */
+#define USB_TRANS_READ       BIT(0)   /** Read transfer flag */
+#define USB_TRANS_WRITE      BIT(1)   /** Write transfer flag */
+#define USB_TRANS_NO_ZLP     BIT(2)   /** No zero-length packet flag */
+
+/**
+ * @brief Transfer management endpoint callback
+ *
+ * If a USB class driver wants to use high-level transfer functions, driver
+ * needs to register this callback as usb endpoint callback.
+ */
+void usb_transfer_ep_callback(uint8_t ep, enum usb_dc_ep_cb_status_code);
+
+/**
+ * @brief Start a transfer
+ *
+ * Start a usb transfer to/from the data buffer. This function is asynchronous
+ * and can be executed in IRQ context. The provided callback will be called
+ * on transfer completion (or error) in thread context.
+ *
+ * @param[in]  ep           Endpoint address corresponding to the one
+ *                          listed in the device configuration table
+ * @param[in]  data         Pointer to data buffer to write-to/read-from
+ * @param[in]  dlen         Size of data buffer
+ * @param[in]  flags        Transfer flags (USB_TRANS_READ, USB_TRANS_WRITE...)
+ * @param[in]  cb           Function called on transfer completion/failure
+ * @param[in]  priv         Data passed back to the transfer completion callback
+ *
+ * @return 0 on success, negative errno code on fail.
+ */
+int usb_transfer(uint8_t ep, uint8_t *data, size_t dlen, unsigned int flags,
+                 usb_transfer_callback cb, void *priv);
+
+/**
+ * @brief Start a transfer and block-wait for completion
+ *
+ * Synchronous version of usb_transfer, wait for transfer completion before
+ * returning.
+ *
+ * @param[in]  ep           Endpoint address corresponding to the one
+ *                          listed in the device configuration table
+ * @param[in]  data         Pointer to data buffer to write-to/read-from
+ * @param[in]  dlen         Size of data buffer
+ * @param[in]  flags        Transfer flags
+
+ *
+ * @return number of bytes transferred on success, negative errno code on fail.
+ */
+int usb_transfer_sync(uint8_t ep, uint8_t *data, size_t dlen, unsigned int flags);
+
+/**
+ * @brief Cancel any ongoing transfer on the specified endpoint
+ *
+ * @param[in]  ep           Endpoint address corresponding to the one
+ *                          listed in the device configuration table
+ *
+ * @return 0 on success, negative errno code on fail.
+ */
+void usb_cancel_transfer(uint8_t ep);
+
+
+void usb_dev_resume(int configuration);
+int usb_dev_get_configuration(void);
+
+
+#ifdef __cplusplus
+}
+#endif
+

components/esp_rom/include/esp32s2/rom/usb/usb_dfu.h

@@ -0,0 +1,147 @@
+/***************************************************************************
+ *
+ * Copyright(c) 2015,2016 Intel Corporation.
+ * Copyright(c) 2017 PHYTEC Messtechnik GmbH
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ * * Neither the name of Intel Corporation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ ***************************************************************************/
+
+/**
+ * @file
+ * @brief USB Device Firmware Upgrade (DFU) public header
+ *
+ * Header follows the Device Class Specification for
+ * Device Firmware Upgrade Version 1.1
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <stddef.h>
+#include "usb_device.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** DFU Class Subclass */
+#define DFU_SUBCLASS            0x01
+
+/** DFU Class runtime Protocol */
+#define DFU_RT_PROTOCOL         0x01
+
+/** DFU Class DFU mode Protocol */
+#define DFU_MODE_PROTOCOL       0x02
+
+/**
+ * @brief DFU Class Specific Requests
+ */
+#define DFU_DETACH          0x00
+#define DFU_DNLOAD          0x01
+#define DFU_UPLOAD          0x02
+#define DFU_GETSTATUS           0x03
+#define DFU_CLRSTATUS           0x04
+#define DFU_GETSTATE            0x05
+#define DFU_ABORT           0x06
+
+/** DFU FUNCTIONAL descriptor type */
+#define DFU_FUNC_DESC           0x21
+
+/** DFU attributes DFU Functional Descriptor */
+#define DFU_ATTR_WILL_DETACH        0x08
+#define DFU_ATTR_MANIFESTATION_TOLERANT 0x04
+#define DFU_ATTR_CAN_UPLOAD     0x02
+#define DFU_ATTR_CAN_DNLOAD     0x01
+
+/** DFU Specification release */
+#define DFU_VERSION         0x0110
+
+/** Run-Time Functional Descriptor */
+struct dfu_runtime_descriptor {
+    uint8_t bLength;
+    uint8_t bDescriptorType;
+    uint8_t bmAttributes;
+    uint16_t wDetachTimeOut;
+    uint16_t wTransferSize;
+    uint16_t bcdDFUVersion;
+} __packed;
+
+/** bStatus values for the DFU_GETSTATUS response */
+enum dfu_status {
+    statusOK,
+    errTARGET,
+    errFILE,
+    errWRITE,
+    errERASE,
+    errCHECK_ERASED,
+    errPROG,
+    errVERIFY,
+    errADDRESS,
+    errNOTDONE,
+    errFIRMWARE,
+    errVENDOR,
+    errUSB,
+    errPOR,
+    errUNKNOWN,
+    errSTALLEDPKT
+};
+
+/** bState values for the DFU_GETSTATUS response */
+enum dfu_state {
+    appIDLE,
+    appDETACH,
+    dfuIDLE,
+    dfuDNLOAD_SYNC,
+    dfuDNBUSY,
+    dfuDNLOAD_IDLE,
+    dfuMANIFEST_SYNC,
+    dfuMANIFEST,
+    dfuMANIFEST_WAIT_RST,
+    dfuUPLOAD_IDLE,
+    dfuERROR,
+};
+
+/*
+ These callbacks are made public so the ACM driver can call them to handle the switch to DFU.
+*/
+
+int dfu_class_handle_req(struct usb_setup_packet *pSetup,
+                         int32_t *data_len, uint8_t **data);
+void dfu_status_cb(enum usb_dc_status_code status, uint8_t *param);
+int usb_dfu_init(void);
+int dfu_custom_handle_req(struct usb_setup_packet *pSetup,
+                          int32_t *data_len, uint8_t **data);
+
+
+typedef void(*usb_dfu_detach_routine_t)(int delay);
+void usb_dfu_set_detach_cb(usb_dfu_detach_routine_t cb);
+
+
+#ifdef __cplusplus
+}
+#endif

components/esp_rom/include/esp32s2/rom/usb/usb_os_glue.h

@@ -0,0 +1,40 @@
+// Copyright 2019-2020 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+typedef void(*usb_osglue_intdisena_routine_t)(void);
+typedef int(*usb_osglue_wait_routine_t)(int delay_us);
+
+typedef struct {
+    /* Disable USB interrupt */
+    usb_osglue_intdisena_routine_t int_dis_proc;
+    /* Enable USB interrupt */
+    usb_osglue_intdisena_routine_t int_ena_proc;
+    /* Wait for a set amount of uS. Return the amount actually waited. If delay_us is 0, just yield.*/
+    usb_osglue_wait_routine_t wait_proc;
+} usb_osglue_data_t;
+
+extern usb_osglue_data_t rom_usb_osglue;
+
+#ifdef __cplusplus
+}
+#endif

components/esp_rom/include/esp32s2/rom/usb/usb_persist.h

@@ -0,0 +1,50 @@
+// Copyright 2019-2020 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// USB persistence flags.
+
+//This bit indicates persistence has been enabled, that is, the USB initialization routines should not
+//reset the USB device as the device still is initialized and the host detected it with the same cdcacm/dfu
+//descriptor as the ROM uses; we can just re-initialize the software side and have at 'er.
+#define USBDC_PERSIST_ENA (1<<31)
+
+//This bit indicates to the ROM that we rebooted because of a request to go into DFU mode; the ROM should
+//honour this request.
+#define USBDC_BOOT_DFU (1<<30)
+
+
+//This being non-0 indicates a memory location where a 'testament' is stored, aka a piece of text that should be output
+//after a reboot. Can contain core dump info or something.
+#define USBDC_TESTAMENT_LOC_MASK 0x7FFFF //bits 19-0; this is added to a base address of 0x3FF80000.
+
+//The testament is a FIFO. The ROM will output all data between textstart and textend; if textend is lower than textstart it will
+//output everything from textstart to memend, then memstart to textend.
+typedef struct {
+    char *memstart; //start of memory region
+    char *memend;   //end of memory region
+    char *textstart; //start of text to output
+    char *textend;
+} usbdc_testament_t;
+
+#ifdef __cplusplus
+}
+#endif

components/esp_system/include/esp_private/usb_console.h

@@ -0,0 +1,73 @@
+// Copyright 2019-2020 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include "esp_err.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @file usb_console.h
+ * This file contains definitions of low-level USB console functions.
+ * These functions are not considered to be a public interface and
+ * should not be called by applications directly.
+ * Application interface to the USB console is provided either by
+ * "cdcacm" VFS driver, or by the USB CDC driver in TinyUSB.
+ */
+
+
+/**
+ * RX/TX callback function type
+ * @param arg  callback-specific context pointer
+ */
+typedef void (*esp_usb_console_cb_t)(void* arg);
+
+/**
+ * Initialize USB console output using ROM USB CDC driver.
+ * This function is called by the early startup code if USB CDC is
+ * selected as the console output option.
+ * @return
+ *  - ESP_OK on success
+ *  - ESP_ERR_NO_MEM
+ *  - other error codes from the interrupt allocator
+ */
+esp_err_t esp_usb_console_init(void);
+
+/**
+ * Write a buffer to USB CDC
+ * @param buf  data to write
+ * @param size  size of the data, in bytes
+ * @return -1 on error, otherwise the number of bytes
+ */
+ssize_t esp_usb_console_write_buf(const char* buf, size_t size);
+
+ssize_t esp_usb_console_flush(void);
+
+ssize_t esp_usb_console_read_buf(char* buf, size_t buf_size);
+
+bool esp_usb_console_read_available(void);
+
+bool esp_usb_console_write_available(void);
+
+esp_err_t esp_usb_console_set_cb(esp_usb_console_cb_t rx_cb, esp_usb_console_cb_t tx_cb, void* arg);
+
+#ifdef __cplusplus
+}
+#endif

components/esp_system/linker.lf

@@ -3,4 +3,25 @@ archive: libesp_system.a
 entries:
     panic (noflash)
     panic_handler (noflash)
-    system_api:esp_system_abort (noflash)
+    reset_reason (noflash)
+    system_api:esp_system_abort (noflash)
+
+    if ESP_CONSOLE_USB_CDC_SUPPORT_ETS_PRINTF:
+        usb_console:esp_usb_console_write_char (noflash)
+        usb_console:esp_usb_console_write_buf (noflash)
+        usb_console:esp_usb_console_flush_internal (noflash)
+        usb_console:esp_usb_console_osglue_wait_proc (noflash)
+        usb_console:esp_usb_console_osglue_dis_int (noflash)
+        usb_console:esp_usb_console_osglue_ena_int (noflash)
+        usb_console:esp_usb_console_interrupt (noflash)
+        usb_console:esp_usb_console_poll_interrupts (noflash)
+        usb_console:esp_usb_console_cdc_acm_cb (noflash)
+        usb_console:esp_usb_console_dfu_detach_cb (noflash)
+        usb_console:esp_usb_console_before_restart (noflash)
+
+[mapping:vfs_cdcacm]
+archive: libvfs.a
+entries:
+    if ESP_CONSOLE_USB_CDC_SUPPORT_ETS_PRINTF:
+        vfs_cdcacm:cdcacm_tx_cb (noflash)
+        vfs_cdcacm:cdcacm_rx_cb (noflash)

components/esp_system/panic.c

@@ -19,6 +19,7 @@
 #include "esp_spi_flash.h"
 #include "esp_private/system_internal.h"
 #include "esp_private/gdbstub.h"
+#include "esp_private/usb_console.h"
 #include "esp_ota_ops.h"
 
 #if CONFIG_APPTRACE_ENABLE
@@ -62,6 +63,7 @@ static wdt_hal_context_t wdt1_context = {.inst = WDT_MWDT1, .mwdt_dev = &TIMERG1
 
 #if !CONFIG_ESP_SYSTEM_PANIC_SILENT_REBOOT
 
+#if CONFIG_ESP_CONSOLE_UART
 static uart_hal_context_t s_panic_uart = { .dev = CONFIG_ESP_CONSOLE_UART_NUM == 0 ? &UART0 : &UART1 };
 
 void panic_print_char(const char c)
@@ -70,6 +72,23 @@ void panic_print_char(const char c)
     while(!uart_hal_get_txfifo_len(&s_panic_uart));
     uart_hal_write_txfifo(&s_panic_uart, (uint8_t*) &c, 1, &sz);
 }
+#endif // CONFIG_ESP_CONSOLE_UART
+
+
+#if CONFIG_ESP_CONSOLE_USB_CDC
+void panic_print_char(const char c)
+{
+    esp_usb_console_write_buf(&c, 1);
+    /* result ignored */
+}
+#endif // CONFIG_ESP_CONSOLE_USB_CDC
+
+#if CONFIG_ESP_CONSOLE_NONE
+void panic_print_char(const char c)
+{
+    /* no-op */
+}
+#endif // CONFIG_ESP_CONSOLE_NONE
 
 void panic_print_str(const char *str)
 {

components/esp_system/port/cpu_start.c

@@ -355,7 +355,7 @@ void IRAM_ATTR call_start_cpu0(void)
     esp_perip_clk_init();
     intr_matrix_clear();
 
-#ifndef CONFIG_ESP_CONSOLE_UART_NONE
+#ifdef CONFIG_ESP_CONSOLE_UART
     const int uart_clk_freq = APB_CLK_FREQ;
     uart_div_modify(CONFIG_ESP_CONSOLE_UART_NUM, (uart_clk_freq << 4) / CONFIG_ESP_CONSOLE_UART_BAUDRATE);
 #endif

components/esp_system/port/esp32/clk.c

@@ -187,7 +187,9 @@ void esp_clk_init(void)
 
     // Wait for UART TX to finish, otherwise some UART output will be lost
     // when switching APB frequency
-    uart_tx_wait_idle(CONFIG_ESP_CONSOLE_UART_NUM);
+    if (CONFIG_ESP_CONSOLE_UART_NUM >= 0) {
+        uart_tx_wait_idle(CONFIG_ESP_CONSOLE_UART_NUM);
+    }
 
     rtc_clk_cpu_freq_set_config(&new_config);
 

components/esp_system/port/esp32s2/CMakeLists.txt

@@ -2,3 +2,6 @@ set(srcs "dport_panic_highint_hdl.S" "clk.c" "reset_reason.c")
 add_prefix(srcs "${CMAKE_CURRENT_LIST_DIR}/" ${srcs})
 
 target_sources(${COMPONENT_LIB} PRIVATE ${srcs})
+if(CONFIG_ESP_CONSOLE_USB_CDC)
+    target_sources(${COMPONENT_LIB} PRIVATE "${CMAKE_CURRENT_LIST_DIR}/usb_console.c")
+endif()

components/esp_system/port/esp32s2/clk.c

@@ -132,7 +132,9 @@ void esp_clk_init(void)
 
     // Wait for UART TX to finish, otherwise some UART output will be lost
     // when switching APB frequency
-    uart_tx_wait_idle(CONFIG_ESP_CONSOLE_UART_NUM);
+    if (CONFIG_ESP_CONSOLE_UART_NUM >= 0) {
+        uart_tx_wait_idle(CONFIG_ESP_CONSOLE_UART_NUM);
+    }
 
     rtc_clk_cpu_freq_set_config(&new_config);
 
@@ -271,7 +273,9 @@ void esp_perip_clk_init(void)
 #if CONFIG_ESP_CONSOLE_UART_NUM != 1
                         DPORT_UART1_CLK_EN |
 #endif
+#ifndef CONFIG_ESP32S2_KEEP_USB_ALIVE
                         DPORT_USB_CLK_EN |
+#endif
                         DPORT_SPI2_CLK_EN |
                         DPORT_I2C_EXT0_CLK_EN |
                         DPORT_UHCI0_CLK_EN |

components/esp_system/port/esp32s2/usb_console.c

@@ -0,0 +1,425 @@
+// Copyright 2019-2020 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+#include <sys/param.h>
+#include "sdkconfig.h"
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "freertos/semphr.h"
+#include "esp_system.h"
+#include "esp_intr_alloc.h"
+#include "esp_private/usb_console.h"
+#include "soc/periph_defs.h"
+#include "soc/rtc_cntl_reg.h"
+#include "soc/usb_struct.h"
+#include "soc/usb_reg.h"
+#include "soc/spinlock.h"
+#include "hal/soc_hal.h"
+#include "esp32s2/rom/uart.h"
+#include "esp32s2/rom/usb/usb_dc.h"
+#include "esp32s2/rom/usb/cdc_acm.h"
+#include "esp32s2/rom/usb/usb_dfu.h"
+#include "esp32s2/rom/usb/usb_device.h"
+#include "esp32s2/rom/usb/usb_os_glue.h"
+#include "esp32s2/rom/usb/usb_persist.h"
+#include "esp32s2/rom/usb/chip_usb_dw_wrapper.h"
+
+
+#define CDC_WORK_BUF_SIZE (CDC_ACM_WORK_BUF_MIN + CONFIG_ESP_CONSOLE_USB_CDC_RX_BUF_SIZE)
+
+typedef enum {
+    REBOOT_NONE,
+    REBOOT_NORMAL,
+    REBOOT_BOOTLOADER,
+    REBOOT_BOOTLOADER_DFU,
+} reboot_type_t;
+
+
+static reboot_type_t s_queue_reboot = REBOOT_NONE;
+static int s_prev_rts_state;
+static intr_handle_t s_usb_int_handle;
+static cdc_acm_device *s_cdc_acm_device;
+static char s_usb_tx_buf[ACM_BYTES_PER_TX];
+static size_t s_usb_tx_buf_pos;
+static uint8_t cdcmem[CDC_WORK_BUF_SIZE];
+static esp_usb_console_cb_t s_rx_cb;
+static esp_usb_console_cb_t s_tx_cb;
+static void *s_cb_arg;
+
+#ifdef CONFIG_ESP_CONSOLE_USB_CDC_SUPPORT_ETS_PRINTF
+static spinlock_t s_write_lock = SPINLOCK_INITIALIZER;
+void esp_usb_console_write_char(char c);
+#define ISR_FLAG  ESP_INTR_FLAG_IRAM
+#else
+#define ISR_FLAG  0
+#endif // CONFIG_ESP_CONSOLE_USB_CDC_SUPPORT_ETS_PRINTF
+
+
+/* Optional write lock routines; used only if ets_printf output via CDC is enabled */
+static inline void write_lock_acquire(void);
+static inline void write_lock_release(void);
+
+/* The two functions below need to be revisited in the multicore case */
+_Static_assert(SOC_CPU_CORES_NUM == 1, "usb_osglue_*_int is not multicore capable");
+
+/* Called by ROM to disable the interrupts
+ * Non-static to allow placement into IRAM by ldgen.
+ */
+void esp_usb_console_osglue_dis_int(void)
+{
+    if (s_usb_int_handle) {
+        esp_intr_disable(s_usb_int_handle);
+    }
+}
+
+/* Called by ROM to enable the interrupts
+ * Non-static to allow placement into IRAM by ldgen.
+ */
+void esp_usb_console_osglue_ena_int(void)
+{
+    if (s_usb_int_handle) {
+        esp_intr_enable(s_usb_int_handle);
+    }
+}
+
+/* Delay function called by ROM USB driver.
+ * Non-static to allow placement into IRAM by ldgen.
+ */
+int esp_usb_console_osglue_wait_proc(int delay_us)
+{
+    if (xTaskGetSchedulerState() != taskSCHEDULER_RUNNING ||
+            !xPortCanYield()) {
+        ets_delay_us(delay_us);
+        return delay_us;
+    }
+    if (delay_us == 0) {
+        /* We should effectively yield */
+        vPortYield();
+        return 1;
+    } else {
+        /* Just delay */
+        int ticks = MAX(delay_us / (portTICK_PERIOD_MS * 1000), 1);
+        vTaskDelay(ticks);
+        return ticks * portTICK_PERIOD_MS * 1000;
+    }
+}
+
+/* Called by ROM CDC ACM driver from interrupt context./
+ * Non-static to allow placement into IRAM by ldgen.
+ */
+void esp_usb_console_cdc_acm_cb(cdc_acm_device *dev, int status)
+{
+    if (status == USB_DC_RESET || status == USB_DC_CONNECTED) {
+        s_prev_rts_state = 0;
+    } else if (status == ACM_STATUS_LINESTATE_CHANGED) {
+        uint32_t rts, dtr;
+        cdc_acm_line_ctrl_get(dev, LINE_CTRL_RTS, &rts);
+        cdc_acm_line_ctrl_get(dev, LINE_CTRL_DTR, &dtr);
+        if (!rts && s_prev_rts_state) {
+            if (dtr) {
+                s_queue_reboot = REBOOT_BOOTLOADER;
+            } else {
+                s_queue_reboot = REBOOT_NORMAL;
+            }
+        }
+        s_prev_rts_state = rts;
+    } else if (status == ACM_STATUS_RX && s_rx_cb) {
+        (*s_rx_cb)(s_cb_arg);
+    } else if (status == ACM_STATUS_TX && s_tx_cb) {
+        (*s_tx_cb)(s_cb_arg);
+    }
+}
+
+/* Non-static to allow placement into IRAM by ldgen. */
+void esp_usb_console_dfu_detach_cb(int timeout)
+{
+    s_queue_reboot = REBOOT_BOOTLOADER_DFU;
+}
+
+/* USB interrupt handler, forward the call to the ROM driver.
+ * Non-static to allow placement into IRAM by ldgen.
+ */
+void esp_usb_console_interrupt(void *arg)
+{
+    usb_dc_check_poll_for_interrupts();
+    /* Restart can be requested from esp_usb_console_cdc_acm_cb or esp_usb_console_dfu_detach_cb */
+    if (s_queue_reboot != REBOOT_NONE) {
+        esp_restart();
+    }
+}
+
+/* Call the USB interrupt handler while any interrupts are pending,
+ * but not more than a few times.
+ * Non-static to allow placement into IRAM by ldgen.
+ */
+void esp_usb_console_poll_interrupts(void)
+{
+    const int max_poll_count = 10;
+    for (int i = 0; (USB0.gintsts & USB0.gintmsk) != 0 && i < max_poll_count; i++) {
+        usb_dc_check_poll_for_interrupts();
+    }
+}
+
+/* This function gets registered as a restart handler.
+ * Prepares USB peripheral for restart and sets up persistence.
+ * Non-static to allow placement into IRAM by ldgen.
+ */
+void esp_usb_console_before_restart(void)
+{
+    esp_usb_console_poll_interrupts();
+    usb_dc_prepare_persist();
+    if (s_queue_reboot == REBOOT_BOOTLOADER) {
+        chip_usb_set_persist_flags(USBDC_PERSIST_ENA);
+        REG_WRITE(RTC_CNTL_OPTION1_REG, RTC_CNTL_FORCE_DOWNLOAD_BOOT);
+    } else if (s_queue_reboot == REBOOT_BOOTLOADER_DFU) {
+        chip_usb_set_persist_flags(USBDC_BOOT_DFU);
+        REG_WRITE(RTC_CNTL_OPTION1_REG, RTC_CNTL_FORCE_DOWNLOAD_BOOT);
+    } else {
+        chip_usb_set_persist_flags(USBDC_PERSIST_ENA);
+        esp_usb_console_poll_interrupts();
+    }
+}
+
+/* Reset some static state in ROM, which survives when going from the
+ * 2nd stage bootloader into the app. This cleans some variables which
+ * indicates that the driver is already initialized, allowing us to
+ * initialize it again, in the app.
+ */
+static void esp_usb_console_rom_cleanup(void)
+{
+    extern char rom_usb_dev, rom_usb_dev_end;
+    extern char rom_usb_dw_ctrl, rom_usb_dw_ctrl_end;
+
+    uart_acm_dev = NULL;
+    memset((void *) &rom_usb_dev, 0, &rom_usb_dev_end - &rom_usb_dev);
+    memset((void *) &rom_usb_dw_ctrl, 0, &rom_usb_dw_ctrl_end - &rom_usb_dw_ctrl);
+}
+
+esp_err_t esp_usb_console_init(void)
+{
+    esp_err_t err;
+    err = esp_register_shutdown_handler(esp_usb_console_before_restart);
+    if (err != ESP_OK) {
+        return err;
+    }
+
+    esp_usb_console_rom_cleanup();
+
+    /* Install OS hooks */
+    rom_usb_osglue.int_dis_proc = esp_usb_console_osglue_dis_int;
+    rom_usb_osglue.int_ena_proc = esp_usb_console_osglue_ena_int;
+    rom_usb_osglue.wait_proc = esp_usb_console_osglue_wait_proc;
+
+    /* Install interrupt.
+     * In case of ESP_CONSOLE_USB_CDC_SUPPORT_ETS_PRINTF:
+     *   Note that this the interrupt handler has to be placed into IRAM because
+     *   the interrupt handler can also be called in polling mode, when
+     *   interrupts are disabled, and a write to USB is performed with cache disabled.
+     *   Since the handler function is in IRAM, we can register the interrupt as IRAM capable.
+     *   It is not because we actually need the interrupt to work with cache disabled!
+     */
+    err = esp_intr_alloc(ETS_USB_INTR_SOURCE, ISR_FLAG | ESP_INTR_FLAG_INTRDISABLED,
+            esp_usb_console_interrupt, NULL, &s_usb_int_handle);
+    if (err != ESP_OK) {
+        esp_unregister_shutdown_handler(esp_usb_console_before_restart);
+        return err;
+    }
+
+    /* Initialize USB / CDC */
+    s_cdc_acm_device = cdc_acm_init(cdcmem, CDC_WORK_BUF_SIZE);
+    usb_dc_check_poll_for_interrupts();
+
+    /* Set callback for handling DTR/RTS lines and TX/RX events */
+    cdc_acm_irq_callback_set(s_cdc_acm_device, esp_usb_console_cdc_acm_cb);
+    cdc_acm_irq_state_enable(s_cdc_acm_device);
+
+    /* Set callback for handling DFU detach */
+    usb_dfu_set_detach_cb(esp_usb_console_dfu_detach_cb);
+
+    /* Enable interrupts on USB peripheral side */
+    USB0.gahbcfg |= USB_GLBLLNTRMSK_M;
+
+    /* Enable the interrupt handler */
+    esp_intr_enable(s_usb_int_handle);
+
+#ifdef CONFIG_ESP_CONSOLE_USB_CDC_SUPPORT_ETS_PRINTF
+    /* Install ets_printf handler */
+    ets_install_putc1(&esp_usb_console_write_char);
+#endif // CONFIG_ESP_CONSOLE_USB_CDC_SUPPORT_ETS_PRINTF
+
+    return ESP_OK;
+}
+
+/* Non-static to allow placement into IRAM by ldgen.
+ * Must be called with the write lock held.
+ */
+ssize_t esp_usb_console_flush_internal(size_t last_write_size)
+{
+    if (s_usb_tx_buf_pos == 0) {
+        return 0;
+    }
+    assert(s_usb_tx_buf_pos >= last_write_size);
+    ssize_t ret;
+    size_t tx_buf_pos_before = s_usb_tx_buf_pos - last_write_size;
+    int sent = cdc_acm_fifo_fill(s_cdc_acm_device, (const uint8_t*) s_usb_tx_buf, s_usb_tx_buf_pos);
+    if (sent == last_write_size) {
+        /* everything was sent */
+        ret = last_write_size;
+        s_usb_tx_buf_pos = 0;
+    } else if (sent == 0) {
+        /* nothing was sent, roll back to the original state */
+        ret = 0;
+        s_usb_tx_buf_pos = tx_buf_pos_before;
+    } else {
+        /* Some data was sent, but not all of the buffer.
+         * We can still tell the caller that all the new data
+         * was "sent" since it is in the buffer now.
+         */
+        ret = last_write_size;
+        memmove(s_usb_tx_buf, s_usb_tx_buf + sent, s_usb_tx_buf_pos - sent);
+        s_usb_tx_buf_pos = s_usb_tx_buf_pos - sent;
+    }
+    return ret;
+}
+
+ssize_t esp_usb_console_flush(void)
+{
+    if (s_cdc_acm_device == NULL) {
+        return -1;
+    }
+    write_lock_acquire();
+    int ret = esp_usb_console_flush_internal(0);
+    write_lock_release();
+    return ret;
+}
+
+ssize_t esp_usb_console_write_buf(const char* buf, size_t size)
+{
+    if (s_cdc_acm_device == NULL) {
+        return -1;
+    }
+    if (size == 0) {
+        return 0;
+    }
+    write_lock_acquire();
+    ssize_t tx_buf_available = ACM_BYTES_PER_TX - s_usb_tx_buf_pos;
+    ssize_t will_write = MIN(size, tx_buf_available);
+    memcpy(s_usb_tx_buf + s_usb_tx_buf_pos, buf, will_write);
+    s_usb_tx_buf_pos += will_write;
+
+    ssize_t ret;
+    if (s_usb_tx_buf_pos == ACM_BYTES_PER_TX || buf[size - 1] == '\n') {
+        /* Buffer is full, or a newline is found.
+         * For binary streams, we probably shouldn't do line buffering,
+         * but text streams are likely going to be the most common case.
+         */
+        ret = esp_usb_console_flush_internal(will_write);
+    } else {
+        /* nothing sent out yet, but all the new data is in the buffer now */
+        ret = will_write;
+    }
+    write_lock_release();
+    return ret;
+}
+
+ssize_t esp_usb_console_read_buf(char *buf, size_t buf_size)
+{
+    if (s_cdc_acm_device == NULL) {
+        return -1;
+    }
+    if (!esp_usb_console_read_available()) {
+        return 0;
+    }
+    int bytes_read = cdc_acm_fifo_read(s_cdc_acm_device, (uint8_t*) buf, buf_size);
+    return bytes_read;
+}
+
+esp_err_t esp_usb_console_set_cb(esp_usb_console_cb_t rx_cb, esp_usb_console_cb_t tx_cb, void *arg)
+{
+    if (s_cdc_acm_device == NULL) {
+        return ESP_ERR_INVALID_STATE;
+    }
+    s_rx_cb = rx_cb;
+    if (s_rx_cb) {
+        cdc_acm_irq_rx_enable(s_cdc_acm_device);
+    } else {
+        cdc_acm_irq_rx_disable(s_cdc_acm_device);
+    }
+    s_tx_cb = tx_cb;
+    if (s_tx_cb) {
+        cdc_acm_irq_tx_enable(s_cdc_acm_device);
+    } else {
+        cdc_acm_irq_tx_disable(s_cdc_acm_device);
+    }
+    s_cb_arg = arg;
+    return ESP_OK;
+}
+
+bool esp_usb_console_read_available(void)
+{
+    if (s_cdc_acm_device == NULL) {
+        return false;
+    }
+    return cdc_acm_rx_fifo_cnt(s_cdc_acm_device) > 0;
+}
+
+bool esp_usb_console_write_available(void)
+{
+    if (s_cdc_acm_device == NULL) {
+        return false;
+    }
+    return cdc_acm_irq_tx_ready(s_cdc_acm_device) != 0;
+}
+
+
+#ifdef CONFIG_ESP_CONSOLE_USB_CDC_SUPPORT_ETS_PRINTF
+/* Used as an output function by ets_printf.
+ * The LF->CRLF replacement logic replicates the one in ets_write_char_uart.
+ * Not static to allow placement into IRAM by ldgen.
+ */
+void esp_usb_console_write_char(char c)
+{
+    char cr = '\r';
+    char lf = '\n';
+
+    if (c == lf) {
+        esp_usb_console_write_buf(&cr, 1);
+        esp_usb_console_write_buf(&lf, 1);
+    } else if (c == '\r') {
+    } else {
+        esp_usb_console_write_buf(&c, 1);
+    }
+}
+static inline void write_lock_acquire(void)
+{
+    spinlock_acquire(&s_write_lock, SPINLOCK_WAIT_FOREVER);
+}
+static inline void write_lock_release(void)
+{
+    spinlock_release(&s_write_lock);
+}
+
+#else // CONFIG_ESP_CONSOLE_USB_CDC_SUPPORT_ETS_PRINTF
+
+static inline void write_lock_acquire(void)
+{
+}
+
+static inline void write_lock_release(void)
+{
+}
+#endif // CONFIG_ESP_CONSOLE_USB_CDC_SUPPORT_ETS_PRINTF

components/esp_system/startup.c

@@ -50,6 +50,9 @@
 #include "esp_pm.h"
 #include "esp_private/pm_impl.h"
 #include "esp_pthread.h"
+#include "esp_private/usb_console.h"
+#include "esp_vfs_cdcacm.h"
+
 
 // [refactor-todo] make this file completely target-independent
 #if CONFIG_IDF_TARGET_ESP32
@@ -202,18 +205,25 @@ static void IRAM_ATTR do_core_init(void)
 #endif
 
 #ifdef CONFIG_VFS_SUPPORT_IO
+#ifdef CONFIG_ESP_CONSOLE_UART
     esp_vfs_dev_uart_register();
+    const char *default_stdio_dev = "/dev/uart/" STRINGIFY(CONFIG_ESP_CONSOLE_UART_NUM);
+#endif // CONFIG_ESP_CONSOLE_UART
+#ifdef CONFIG_ESP_CONSOLE_USB_CDC
+    ESP_ERROR_CHECK(esp_usb_console_init());
+    ESP_ERROR_CHECK(esp_vfs_dev_cdcacm_register());
+    const char *default_stdio_dev = "/dev/cdcacm";
+#endif // CONFIG_ESP_CONSOLE_USB_CDC
 #endif // CONFIG_VFS_SUPPORT_IO
 
-#if defined(CONFIG_VFS_SUPPORT_IO) && !defined(CONFIG_ESP_CONSOLE_UART_NONE)
+#if defined(CONFIG_VFS_SUPPORT_IO) && !defined(CONFIG_ESP_CONSOLE_NONE)
     esp_reent_init(_GLOBAL_REENT);
-    const char *default_uart_dev = "/dev/uart/" STRINGIFY(CONFIG_ESP_CONSOLE_UART_NUM);
-    _GLOBAL_REENT->_stdin  = fopen(default_uart_dev, "r");
-    _GLOBAL_REENT->_stdout = fopen(default_uart_dev, "w");
-    _GLOBAL_REENT->_stderr = fopen(default_uart_dev, "w");
-#else // defined(CONFIG_VFS_SUPPORT_IO) && !defined(CONFIG_ESP_CONSOLE_UART_NONE)
+    _GLOBAL_REENT->_stdin  = fopen(default_stdio_dev, "r");
+    _GLOBAL_REENT->_stdout = fopen(default_stdio_dev, "w");
+    _GLOBAL_REENT->_stderr = fopen(default_stdio_dev, "w");
+#else // defined(CONFIG_VFS_SUPPORT_IO) && !defined(CONFIG_ESP_CONSOLE_NONE)
     _REENT_SMALL_CHECK_INIT(_GLOBAL_REENT);
-#endif // defined(CONFIG_VFS_SUPPORT_IO) && !defined(CONFIG_ESP_CONSOLE_UART_NONE)
+#endif // defined(CONFIG_VFS_SUPPORT_IO) && !defined(CONFIG_ESP_CONSOLE_NONE)
 
 #ifdef CONFIG_SECURE_FLASH_ENC_ENABLED
     esp_flash_encryption_init_checks();
@@ -344,7 +354,7 @@ void IRAM_ATTR start_cpu0_default(void)
 
 IRAM_ATTR ESP_SYSTEM_INIT_FN(init_components0, BIT(0))
 {
-#ifdef CONFIG_PM_ENABLE
+#if defined(CONFIG_PM_ENABLE) && defined(CONFIG_ESP_CONSOLE_UART)
     const int uart_clk_freq = REF_CLK_FREQ;
     /* When DFS is enabled, use REFTICK as UART clock source */
     CLEAR_PERI_REG_MASK(UART_CONF0_REG(CONFIG_ESP_CONSOLE_UART_NUM), UART_TICK_REF_ALWAYS_ON);

components/esptool_py/esptool

@@ -1 +1 @@
-Subproject commit 5eada56341f3a74c3e09eef3b1266f1072145059
+Subproject commit 5c60636454c329073b546930d9e375b97258afae

components/soc/src/esp32s2/rtc_clk.c

@@ -41,7 +41,8 @@ static const char *TAG = "rtc_clk";
 #define RTC_PLL_FREQ_480M   480
 
 // Current PLL frequency, in MHZ (320 or 480). Zero if PLL is not enabled.
-static int s_cur_pll_freq;
+// On the ESP32-S2, 480MHz PLL is enabled at reset.
+static int s_cur_pll_freq = RTC_PLL_FREQ_480M;
 
 static void rtc_clk_cpu_freq_to_8m(void);
 
@@ -374,7 +375,7 @@ void rtc_clk_cpu_freq_set_config(const rtc_cpu_freq_config_t* config)
     if (soc_clk_sel != DPORT_SOC_CLK_SEL_XTAL) {
         rtc_clk_cpu_freq_to_xtal(xtal_freq, 1);
     }
-    if (soc_clk_sel == DPORT_SOC_CLK_SEL_PLL) {
+    if (soc_clk_sel == DPORT_SOC_CLK_SEL_PLL && config->source_freq_mhz != s_cur_pll_freq) {
         rtc_clk_bbpll_disable();
     }
     if (config->source == RTC_CPU_FREQ_SRC_XTAL) {
@@ -463,7 +464,7 @@ void rtc_clk_cpu_freq_set_xtal(void)
     int freq_mhz = (int) rtc_clk_xtal_freq_get();
 
     rtc_clk_cpu_freq_to_xtal(freq_mhz, 1);
-    rtc_clk_bbpll_disable();
+    /* BBPLL is kept enabled */
 }
 
 /**

components/vfs/CMakeLists.txt

@@ -3,6 +3,10 @@ idf_component_register(SRCS "vfs.c"
                             "vfs_semihost.c"
                     INCLUDE_DIRS include)
 
+if(CONFIG_ESP_CONSOLE_USB_CDC)
+    target_sources(${COMPONENT_LIB} PRIVATE "vfs_cdcacm.c")
+endif()
+
 # Some newlib syscalls are implemented in vfs.c, make sure these are always
 # seen by the linker
 target_link_libraries(${COMPONENT_LIB} INTERFACE "-u vfs_include_syscalls_impl")

components/vfs/component.mk

@@ -1,5 +1,3 @@
-#
-# Component Makefile
-#
-# (Uses default behaviour of compiling all source files in directory, adding 'include' to include path.)
-
+ifndef CONFIG_ESP_CONSOLE_USB_CDC
+    COMPONENT_OBJEXCLUDE := vfs_cdcacm.o
+endif

components/vfs/include/esp_vfs_cdcacm.h

@@ -0,0 +1,66 @@
+// Copyright 2015-2017 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include "esp_err.h"
+#include "esp_vfs.h"
+#include "esp_vfs_common.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief add /dev/cdcacm virtual filesystem driver
+ *
+ * This function is called from startup code to enable console output
+ */
+esp_err_t esp_vfs_dev_cdcacm_register(void);
+
+/**
+ * @brief Set the line endings expected to be received
+ *
+ * This specifies the conversion between line endings received and
+ * newlines ('\n', LF) passed into stdin:
+ *
+ * - ESP_LINE_ENDINGS_CRLF: convert CRLF to LF
+ * - ESP_LINE_ENDINGS_CR: convert CR to LF
+ * - ESP_LINE_ENDINGS_LF: no modification
+ *
+ * @note this function is not thread safe w.r.t. reading
+ *
+ * @param mode line endings expected
+ */
+void esp_vfs_dev_cdcacm_set_rx_line_endings(esp_line_endings_t mode);
+
+/**
+ * @brief Set the line endings to sent
+ *
+ * This specifies the conversion between newlines ('\n', LF) on stdout and line
+ * endings sent:
+ *
+ * - ESP_LINE_ENDINGS_CRLF: convert LF to CRLF
+ * - ESP_LINE_ENDINGS_CR: convert LF to CR
+ * - ESP_LINE_ENDINGS_LF: no modification
+ *
+ * @note this function is not thread safe w.r.t. writing
+ *
+ * @param mode line endings to send
+ */
+void esp_vfs_dev_cdcacm_set_tx_line_endings(esp_line_endings_t mode);
+
+#ifdef __cplusplus
+}
+#endif

components/vfs/include/esp_vfs_common.h

@@ -0,0 +1,32 @@
+// Copyright 2015-2017 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Line ending settings
+ */
+typedef enum {
+    ESP_LINE_ENDINGS_CRLF,//!< CR + LF
+    ESP_LINE_ENDINGS_CR,  //!< CR
+    ESP_LINE_ENDINGS_LF,  //!< LF
+} esp_line_endings_t;
+
+#ifdef __cplusplus
+}
+#endif

components/vfs/include/esp_vfs_dev.h

@@ -15,20 +15,12 @@
 #pragma once
 
 #include "esp_vfs.h"
+#include "esp_vfs_common.h"
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-/**
- * @brief Line ending settings
- */
-typedef enum {
-    ESP_LINE_ENDINGS_CRLF,//!< CR + LF
-    ESP_LINE_ENDINGS_CR,  //!< CR
-    ESP_LINE_ENDINGS_LF,  //!< LF
-} esp_line_endings_t;
-
 /**
  * @brief add /dev/uart virtual filesystem driver
  *

components/vfs/vfs_cdcacm.c

@@ -0,0 +1,324 @@
+// Copyright 2015-2020 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <string.h>
+#include <stdbool.h>
+#include <stdarg.h>
+#include <sys/errno.h>
+#include <sys/lock.h>
+#include <sys/fcntl.h>
+#include <sys/param.h>
+#include "esp_vfs.h"
+#include "esp_vfs_cdcacm.h"
+#include "esp_attr.h"
+#include "sdkconfig.h"
+
+#include "esp_private/usb_console.h"
+
+// Newline conversion mode when transmitting
+static esp_line_endings_t s_tx_mode =
+#if CONFIG_NEWLIB_STDOUT_LINE_ENDING_CRLF
+    ESP_LINE_ENDINGS_CRLF;
+#elif CONFIG_NEWLIB_STDOUT_LINE_ENDING_CR
+    ESP_LINE_ENDINGS_CR;
+#else
+    ESP_LINE_ENDINGS_LF;
+#endif
+
+// Newline conversion mode when receiving
+static esp_line_endings_t s_rx_mode =
+#if CONFIG_NEWLIB_STDIN_LINE_ENDING_CRLF
+    ESP_LINE_ENDINGS_CRLF;
+#elif CONFIG_NEWLIB_STDIN_LINE_ENDING_CR
+    ESP_LINE_ENDINGS_CR;
+#else
+    ESP_LINE_ENDINGS_LF;
+#endif
+
+#define NONE -1
+
+//Read and write lock, lazily initialized
+static _lock_t s_write_lock;
+static _lock_t s_read_lock;
+
+static bool s_blocking;
+static SemaphoreHandle_t s_rx_semaphore;
+static SemaphoreHandle_t s_tx_semaphore;
+
+static ssize_t cdcacm_write(int fd, const void *data, size_t size)
+{
+    assert(fd == 0);
+    const char *cdata = (const char *)data;
+    _lock_acquire_recursive(&s_write_lock);
+    for (size_t i = 0; i < size; i++) {
+        if (cdata[i] != '\n') {
+            esp_usb_console_write_buf(&cdata[i], 1);
+        } else {
+            if (s_tx_mode == ESP_LINE_ENDINGS_CRLF || s_tx_mode == ESP_LINE_ENDINGS_CR) {
+                char cr = '\r';
+                esp_usb_console_write_buf(&cr, 1);
+            }
+            if (s_tx_mode == ESP_LINE_ENDINGS_CRLF || s_tx_mode == ESP_LINE_ENDINGS_LF) {
+                char lf = '\n';
+                esp_usb_console_write_buf(&lf, 1);
+            }
+        }
+    }
+    _lock_release_recursive(&s_write_lock);
+    return size;
+}
+
+static int cdcacm_fsync(int fd)
+{
+    assert(fd == 0);
+    _lock_acquire_recursive(&s_write_lock);
+    ssize_t written = esp_usb_console_flush();
+    _lock_release_recursive(&s_write_lock);
+    return (written < 0) ? -1 : 0;
+}
+
+static int cdcacm_open(const char *path, int flags, int mode)
+{
+    return 0; // fd 0
+}
+
+static int cdcacm_fstat(int fd, struct stat *st)
+{
+    assert(fd == 0);
+    st->st_mode = S_IFCHR;
+    return 0;
+}
+
+static int cdcacm_close(int fd)
+{
+    assert(fd == 0);
+    return 0;
+}
+
+static int s_peek_char = NONE;
+
+/* Helper function which returns a previous character or reads a new one from
+ * CDC-ACM driver. Previous character can be returned ("pushed back") using
+ * cdcacm_return_char function. Returns NONE if no character is available. Note
+ * the cdcacm driver maintains its own RX buffer and a receive call does not
+ * invoke an USB operation, so there's no penalty to reading data char-by-char.
+ */
+static int cdcacm_read_char(void)
+{
+    /* return character from peek buffer, if it is there */
+    if (s_peek_char != NONE) {
+        int c = s_peek_char;
+        s_peek_char = NONE;
+        return c;
+    }
+    /* Peek buffer is empty; try to read from cdcacm driver. */
+    uint8_t c;
+    ssize_t read = esp_usb_console_read_buf((char *) &c, 1);
+    if (read <= 0) {
+        return NONE;
+    } else {
+        return c;
+    }
+}
+
+static bool cdcacm_data_in_buffer(void)
+{
+    if (s_peek_char != NONE) {
+        return true;
+    }
+    if (esp_usb_console_read_available()) {
+        return true;
+    }
+    return false;
+}
+
+/* Push back a character; it will be returned by next call to cdcacm_read_char */
+static void cdcacm_return_char(int c)
+{
+    assert(s_peek_char == NONE);
+    s_peek_char = c;
+}
+
+static ssize_t cdcacm_read(int fd, void *data, size_t size)
+{
+    assert(fd == 0);
+    char *data_c = (char *) data;
+    ssize_t received = 0;
+    _lock_acquire_recursive(&s_read_lock);
+
+    while (!cdcacm_data_in_buffer()) {
+        if (!s_blocking) {
+            errno = EWOULDBLOCK;
+            _lock_release_recursive(&s_read_lock);
+            return -1;
+        }
+        xSemaphoreTake(s_rx_semaphore, portMAX_DELAY);
+    }
+
+
+    if (s_rx_mode == ESP_LINE_ENDINGS_CR || s_rx_mode == ESP_LINE_ENDINGS_LF) {
+        /* This is easy. Just receive, and if needed replace \r by \n. */
+        received = esp_usb_console_read_buf(data_c, size);
+        if (s_rx_mode == ESP_LINE_ENDINGS_CR) {
+            /* Change CRs to newlines */
+            for (ssize_t i = 0; i < received; i++) {
+                if (data_c[i] == '\r') {
+                    data_c[i] = '\n';
+                }
+            }
+        }
+    } else {
+        while (received < size) {
+            int c = cdcacm_read_char();
+            if (c == '\r') {
+                /* look ahead */
+                int c2 = cdcacm_read_char();
+                if (c2 == NONE) {
+                    /* could not look ahead, put the current character back */
+                    cdcacm_return_char(c);
+                    break;
+                }
+                if (c2 == '\n') {
+                    /* this was \r\n sequence. discard \r, return \n */
+                    c = '\n';
+                } else {
+                    /* \r followed by something else. put the second char back,
+                     * it will be processed on next iteration. return \r now.
+                     */
+                    cdcacm_return_char(c2);
+                }
+            } else if (c == NONE) {
+                break;
+            }
+            data_c[received++] = (char) c;
+            if (c == '\n') {
+                break;
+            }
+        }
+    }
+    _lock_release_recursive(&s_read_lock);
+    if (received > 0) {
+        return received;
+    }
+    errno = EWOULDBLOCK;
+    return -1;
+}
+
+/* Non-static, to be able to place into IRAM by ldgen */
+void cdcacm_rx_cb(void* arg)
+{
+    assert(s_blocking);
+    xSemaphoreGive(s_rx_semaphore);
+}
+
+/* Non-static, to be able to place into IRAM by ldgen */
+void cdcacm_tx_cb(void* arg)
+{
+    assert(s_blocking);
+    xSemaphoreGive(s_tx_semaphore);
+}
+
+static int cdcacm_enable_blocking(void)
+{
+    s_rx_semaphore = xSemaphoreCreateBinary();
+    if (!s_rx_semaphore) {
+        errno = ENOMEM;
+        goto fail;
+    }
+    s_tx_semaphore = xSemaphoreCreateBinary();
+    if (!s_tx_semaphore) {
+        errno = ENOMEM;
+        goto fail;
+    }
+    esp_err_t err = esp_usb_console_set_cb(&cdcacm_rx_cb, &cdcacm_tx_cb, NULL);
+    if (err != ESP_OK) {
+        errno = ENODEV;
+        goto fail;
+    }
+    s_blocking = true;
+    return 0;
+
+fail:
+    if (s_rx_semaphore) {
+        vSemaphoreDelete(s_rx_semaphore);
+        s_rx_semaphore = NULL;
+    }
+    if (s_tx_semaphore) {
+        vSemaphoreDelete(s_tx_semaphore);
+        s_tx_semaphore = NULL;
+    }
+    return -1;
+}
+
+static int cdcacm_disable_blocking(void)
+{
+    esp_usb_console_set_cb(NULL, NULL, NULL); /* ignore any errors */
+    vSemaphoreDelete(s_rx_semaphore);
+    s_rx_semaphore = NULL;
+    vSemaphoreDelete(s_tx_semaphore);
+    s_tx_semaphore = NULL;
+    s_blocking = false;
+    return 0;
+}
+
+
+static int cdcacm_fcntl(int fd, int cmd, int arg)
+{
+    assert(fd == 0);
+    int result;
+    if (cmd == F_GETFL) {
+        result = 0;
+        if (!s_blocking) {
+            result |= O_NONBLOCK;
+        }
+    } else if (cmd == F_SETFL) {
+        bool blocking = (arg & O_NONBLOCK) == 0;
+        result = 0;
+        if (blocking && !s_blocking) {
+            result = cdcacm_enable_blocking();
+        } else if (!blocking && s_blocking) {
+            result = cdcacm_disable_blocking();
+        }
+    } else {
+        /* unsupported operation */
+        result = -1;
+        errno = ENOSYS;
+    }
+    return result;
+}
+
+void esp_vfs_dev_cdcacm_set_tx_line_endings(esp_line_endings_t mode)
+{
+    s_tx_mode = mode;
+}
+
+void esp_vfs_dev_cdcacm_set_rx_line_endings(esp_line_endings_t mode)
+{
+    s_rx_mode = mode;
+}
+
+esp_err_t esp_vfs_dev_cdcacm_register(void)
+{
+    const esp_vfs_t vfs = {
+        .flags = ESP_VFS_FLAG_DEFAULT,
+        .write = &cdcacm_write,
+        .open = &cdcacm_open,
+        .fstat = &cdcacm_fstat,
+        .close = &cdcacm_close,
+        .read = &cdcacm_read,
+        .fcntl = &cdcacm_fcntl,
+        .fsync = &cdcacm_fsync
+    };
+    return esp_vfs_register("/dev/cdcacm", &vfs, NULL);
+}

docs/conf_common.py

@@ -165,6 +165,7 @@ ESP32S2_DOCS = ['esp32s2.rst',
                 'hw-reference/esp32s2/**',
                 'api-guides/ulps2_instruction_set.rst',
                 'api-guides/dfu.rst',
+                'api-guides/usb-console.rst',
                 'api-reference/peripherals/hmac.rst',
                 'api-reference/peripherals/ds.rst',
                 'api-reference/peripherals/temp_sensor.rst'

docs/en/api-guides/index.rst

@@ -38,4 +38,5 @@ API Guides
     :esp32: ULP Coprocessor (Legacy GNU Make) <ulp-legacy>
     Unit Testing <unit-tests>
     :esp32: Unit Testing (Legacy GNU Make) <unit-tests-legacy>
+    :esp32s2: USB Console <usb-console>
     WiFi Driver <wifi>

docs/en/api-guides/usb-console.rst

@@ -0,0 +1,105 @@
+***********
+USB Console
+***********
+
+On chips with an integrated USB peripheral, it is possible to use USB Communication Device Class (CDC) to implement the serial console, instead of using UART with an external USB-UART bridge chip. {IDF_TARGET_NAME} ROM code contains a USB CDC implementation, which supports for some basic functionality without requiring the application to include the USB stack:
+
+* Bidirectional serial console, which can be used with :doc:`IDF Monitor <tools/idf-monitor>` or another serial monitor
+* Flashing using ``esptool.py`` and ``idf.py flash``.
+* :doc:`Device Firmware Update (DFU) <dfu>` interface for flashing the device using ``dfu-util`` and ``idf.py dfu``.
+
+.. note::
+
+    At the moment, this "USB Console" feature is incompatible with TinyUSB stack. However, if TinyUSB is used, it can provide its own CDC implementation.
+
+Hardware Requirements
+=====================
+
+Connect ESP32-S2 to the USB port as follows
+
++------+-------------+
+| GPIO | USB         |
++======+=============+
+| 20   | D+ (green)  |
++------+-------------+
+| 19   | D- (white)  |
++------+-------------+
+| GND  | GND (black) |
++------+-------------+
+|      | +5V (red)   |
++------+-------------+
+
+Some development boards may offer a USB connector for the internal USB peripheral — in that case, no extra connections are required.
+
+Software Configuration
+======================
+
+USB console feature can be enabled using ``CONFIG_ESP_CONSOLE_USB_CDC`` option in menuconfig tool (see :ref:`CONFIG_ESP_CONSOLE_UART`).
+
+Once the option is enabled, build the project as usual.
+
+Uploading the Application
+=========================
+
+.. _usb_console_initial_upload:
+
+Initial Upload
+--------------
+
+If the {IDF_TARGET_NAME} is not yet flashed with a program which enables USB console, we can not use ``idf.py flash`` command with the USB CDC port. There are 3 alternative options to perform the initial upload listed below.
+
+Once the initial upload is done, the application will start up and a USB CDC port will appear in the system.
+
+.. note::
+
+    The port name may change after the initial upload, so check the port list again before running ``idf.py monitor``.
+
+
+Initial upload using the ROM download mode, over USB CDC
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+* Press {IDF_TARGET_NAME} into download mode. To do this, keep GPIO0 low while toggling reset. On many development boards, the "Boot" button is connected to GPIO0, and you can press "Reset" button while holding "Boot".
+* A serial port will appear in the system. On most operating systems (Windows 8 and later, Linux, macOS) driver installation is not required. Find the port name using Device Manager (Windows) or by listing ``/dev/ttyACM*`` devices on Linux or ``/dev/cu*`` devices on macOS.
+* Run ``idf.py flash -p PORT`` to upload the application, with ``PORT`` determined in the previous step
+
+Initial upload using the ROM download mode, over USB DFU
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+* Press {IDF_TARGET_NAME} into download mode. To do this, keep GPIO0 low while toggling reset. On many development boards, the "Boot" button is connected to GPIO0, and you can press "Reset" button while holding "Boot".
+* Run ``idf.py dfu-flash``.
+
+See :ref:`api_guide_dfu_flash` for details about DFU flashing.
+
+Initial upload using UART
+^^^^^^^^^^^^^^^^^^^^^^^^^
+
+On development boards with a USB-UART bridge, upload the application over UART: ``idf.py flash -p PORT`` where ``PORT`` is the name of the serial port provided by the USB-UART bridge.
+
+Subsequent Usage
+----------------
+
+Once the application is uploaded for the first time, you can run ``idf.py flash`` and ``idf.py monitor`` as usual.
+
+Limitations
+===========
+
+There are several limitations to the USB console feature. These may or may not be significant, depending on the type of application being developed, and the development workflow. Most of these limitations stem from the fact that USB CDC is implemented in software, so the console working over USB CDC is more fragile and complex than a console working over UART.
+
+1. If the application crashes, panic handler output may not be sent over USB CDC in some cases. If the memory used by the CDC driver is corrupted, or there is some other system-level issue, CDC may not work for sending panic handler messages over USB. This does work in many situations, but is not guaranteed to work as reliably as the UART output does. Similarly, if the application enters a boot loop before the USB CDC driver has a chance to start up, there will be no console output.
+
+2. If the application accidentally reconfigures the USB peripheral pins, or disables the USB peripheral, USB CDC device will disappear from the system. After fixing the issue in the application, you will need to follow the :ref:`usb_console_initial_upload` process to flash the application again.
+
+3. If the application enters light sleep (including automatic light sleep) or deep sleep mode, USB CDC device will disappear from the system.
+
+4. USB CDC driver reserves some amount of RAM and increases application code size. Keep this in mind if trying to optimize application memory usage.
+
+5. By default, the low-level ``ets_printf`` feature and ``ESP_EARLY_LOG`` are disabled when USB CDC is used. These can be enabled using :ref:`CONFIG_ESP_CONSOLE_USB_CDC_SUPPORT_ETS_PRINTF` option. With this option enabled, ``ets_printf`` can be used, at the expense of increased IRAM usage. Keep in mind that the cost of ``ets_printf`` and ``ESP_EARLY_LOG`` over USB CDC is significantly higher than over UART. This makes these logging mechanisms much less suitable for "printf debugging", especially in the interrupt handlers.
+
+6. If you are developing an application which uses the USB peripheral with the TinyUSB stack, this USB Console feature can not be used. This is mainly due to the following reasons:
+
+   * This feature relies on a different USB CDC software stack in {IDF_TARGET_NAME} ROM.
+   * USB descriptors used by the ROM CDC stack may be different from the descriptors used by TinyUSB.
+   * When developing applications which use USB peripheral, it is very likely that USB functionality will not work or will not fully work at some moments during development. This can be due to misconfigured USB descriptors, errors in the USB stack usage, or other reasons. In this case, using the UART console for flashing and monitoring provides a much better development experience.
+
+7. When debugging the application using JTAG, USB CDC may stop working if the CPU is stopped on a breakpoint. USB CDC operation relies on interrupts from the USB peripheral being serviced periodically. If the host computer doesn't receive valid responses from the USB device side for some time, it may decide to disconnect the device. The actual time depends on the OS and the driver, and ranges from a few hundred milliseconds to a few seconds.
+

docs/zh_CN/api-guides/index.rst

@@ -39,3 +39,4 @@ API 指南
    链接脚本生成机制 <linker-script-generation>
    LwIP <lwip>
    Tools <tools/index>
+   :esp32s2: USB console <usb-console>

docs/zh_CN/api-guides/usb-console.rst

@@ -0,0 +1 @@
+.. include:: ../../en/api-guides/usb-console.rst

examples/bluetooth/esp_ble_mesh/ble_mesh_coex_test/main/main.c

@@ -49,7 +49,7 @@ static void initialize_console(void)
      * correct while APB frequency is changing in light sleep mode.
      */
     const uart_config_t uart_config = {
-        .baud_rate = CONFIG_CONSOLE_UART_BAUDRATE,
+        .baud_rate = CONFIG_ESP_CONSOLE_UART_BAUDRATE,
         .data_bits = UART_DATA_8_BITS,
         .parity = UART_PARITY_DISABLE,
         .stop_bits = UART_STOP_BITS_1,

examples/system/console/components/cmd_system/cmd_system.c

@@ -10,6 +10,7 @@
 #include <stdio.h>
 #include <string.h>
 #include <ctype.h>
+#include <unistd.h>
 #include "esp_log.h"
 #include "esp_console.h"
 #include "esp_system.h"
@@ -39,19 +40,29 @@ static void register_light_sleep(void);
 static void register_tasks(void);
 #endif
 
-void register_system(void)
+void register_system_common(void)
 {
     register_free();
     register_heap();
     register_version();
     register_restart();
-    register_deep_sleep();
-    register_light_sleep();
 #if WITH_TASKS_INFO
     register_tasks();
 #endif
 }
 
+void register_system_sleep(void)
+{
+    register_deep_sleep();
+    register_light_sleep();
+}
+
+void register_system(void)
+{
+    register_system_common();
+    register_system_sleep();
+}
+
 /* 'version' command */
 static int get_version(int argc, char **argv)
 {
@@ -124,7 +135,7 @@ static void register_free(void)
 static int heap_size(int argc, char **argv)
 {
     uint32_t heap_size = heap_caps_get_minimum_free_size(MALLOC_CAP_DEFAULT);
-    ESP_LOGI(TAG, "min heap size: %u", heap_size);
+    printf("min heap size: %u\n", heap_size);
     return 0;
 }
 
@@ -285,13 +296,13 @@ static int light_sleep(int argc, char **argv)
     if (io_count > 0) {
         ESP_ERROR_CHECK( esp_sleep_enable_gpio_wakeup() );
     }
-    if (CONFIG_ESP_CONSOLE_UART_NUM <= UART_NUM_1) {
+    if (CONFIG_ESP_CONSOLE_UART_NUM >= 0 && CONFIG_ESP_CONSOLE_UART_NUM <= UART_NUM_1) {
         ESP_LOGI(TAG, "Enabling UART wakeup (press ENTER to exit light sleep)");
         ESP_ERROR_CHECK( uart_set_wakeup_threshold(CONFIG_ESP_CONSOLE_UART_NUM, 3) );
         ESP_ERROR_CHECK( esp_sleep_enable_uart_wakeup(CONFIG_ESP_CONSOLE_UART_NUM) );
     }
     fflush(stdout);
-    uart_wait_tx_idle_polling(CONFIG_ESP_CONSOLE_UART_NUM);
+    fsync(fileno(stdout));
     esp_light_sleep_start();
     esp_sleep_wakeup_cause_t cause = esp_sleep_get_wakeup_cause();
     const char *cause_str;

examples/system/console/components/cmd_system/cmd_system.h

@@ -12,9 +12,15 @@
 extern "C" {
 #endif
 
-// Register system functions
+// Register all system functions
 void register_system(void);
 
+// Register common system functions: "version", "restart", "free", "heap", "tasks"
+void register_system_common(void);
+
+// Register deep and light sleep functions
+void register_system_sleep(void);
+
 #ifdef __cplusplus
 }
 #endif

examples/system/console/main/console_example_main.c

@@ -21,6 +21,10 @@
 #include "nvs.h"
 #include "nvs_flash.h"
 
+#ifdef CONFIG_ESP_CONSOLE_USB_CDC
+#error This example is incompatible with USB CDC console. Please try "console_usb" example instead.
+#endif // CONFIG_ESP_CONSOLE_USB_CDC
+
 static const char* TAG = "example";
 #define PROMPT_STR CONFIG_IDF_TARGET
 

examples/system/console_usb/CMakeLists.txt

@@ -0,0 +1,8 @@
+# The following lines of boilerplate have to be in your project's CMakeLists
+# in this exact order for cmake to work correctly
+cmake_minimum_required(VERSION 3.5)
+
+set(EXTRA_COMPONENT_DIRS $ENV{IDF_PATH}/examples/system/console/components)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+project(console_usb)

examples/system/console_usb/README.md

@@ -0,0 +1,146 @@
+| Supported Targets | ESP32-S2 |
+| ----------------- | -------- |
+
+# USB Console Example
+
+(See the README.md file in the upper level 'examples' directory for more information about examples.)
+
+This example is similar to the [console example](../console/README.md), but instead of the UART it uses USB CDC for console output.
+The example uses the [Console Component](https://docs.espressif.com/projects/esp-idf/en/latest/api-guides/console.html#console) to create an interactive shell.
+
+The interactive shell implemented in this example contains a wide variety of commands, and can act as a basis for applications that require a command-line interface (CLI).
+
+## How to use example
+
+### Hardware Required
+
+This example can run on an ESP32-S2 development board, with a USB cable connected to GPIO19 and GPIO20.
+
+### Build and Flash
+
+Build the project, by running:
+
+```
+idf.py build
+```
+
+First time flashing can be done over USB or over UART.
+
+#### Flashing the project for the first time using UART
+
+This is the same procedure described in the Getting Started Guide. Flashing is done using a USB-Serial adapter included on the development board. Determine the device name of the serial port (`PORT`) and run:
+
+```
+idf.py -p PORT flash
+```
+
+#### Flashing the project for the first time using USB
+
+We can also use the ESP32-S2 built-in USB bootloader to flash the program for the first time.
+
+1. Connect the development board using a USB breakout cable to the computer.
+2. Put the chip into bootloader (download) mode, by holding "Boot" button (connected to GPIO0) and pressing "Reset" button.
+3. A USB serial port device will appear in the system:
+   - On Windows, it will be one of COM ports
+   - On Linux, it will by /dev/ttyACMn (n is some number)
+   - On macOS, it will be /dev/tty.usbmodemN (N is some number)
+
+  If the port doesn't appear, check that the board has entered the bootloader mode, and that the USB cable is connected correctly.
+
+4. Flash the board:
+
+```
+idf.py -p PORT flash
+```
+
+### View the console output over USB
+
+Once the board is flashed for the first time, a USB serial port will appear in the system.
+
+**Note: if you have used the step above to flash the board over USB, note that the port name may change after flashing!**
+
+To start the monitor, run:
+
+```
+idf.py -p PORT monitor
+```
+
+To exit the serial monitor, type ``Ctrl-]``.
+
+See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.
+
+## Example Output
+
+Enter the `help` command get a full list of all available commands. The following is a sample session of the Console Example where a variety of commands provided by the Console Example are used. Note that GPIO15 is connected to GND to remove the boot log output. 
+
+```
+This is an example of ESP-IDF console component.
+Type 'help' to get the list of commands.
+Use UP/DOWN arrows to navigate through command history.
+Press TAB when typing command name to auto-complete.
+esp32s2> help
+help 
+  Print the list of registered commands
+
+free 
+  Get the current size of free heap memory
+
+heap 
+  Get minimum size of free heap memory that was available during program execution
+
+version 
+  Get version of chip and SDK
+
+restart 
+  Software reset of the chip
+
+tasks 
+  Get information about running tasks
+
+(remaining output of the help command skipped here)
+
+esp32s2> free
+237824
+I (39864) cmd_system: Restarting
+I (185) spi_flash: detected chip: generic
+I (186) spi_flash: flash io: dio
+I (186) cpu_start: Starting scheduler on PRO CPU.
+
+This is an example of ESP-IDF console component.
+Type 'help' to get the list of commands.
+Use UP/DOWN arrows to navigate through command history.
+Press TAB when typing command name to auto-complete.
+esp32s2>
+```
+
+## Troubleshooting
+
+### Line Endings
+
+The line endings in the Console Example are configured to match particular serial monitors. Therefore, if the following log output appears, consider using a different serial monitor (e.g. Putty for Windows).
+
+```
+This is an example of ESP-IDF console component.
+Type 'help' to get the list of commands.
+Use UP/DOWN arrows to navigate through command history.
+Press TAB when typing command name to auto-complete.
+Your terminal application does not support escape sequences.
+Line editing and history features are disabled.
+On Windows, try using Putty instead.
+esp32s2>
+```
+
+### No USB port appears
+
+On Windows 10, macOS, Linux, USB CDC devices do not require additional drivers to be installed.
+
+If the USB serial port doesn't appear in the system after flashing the example, check the following:
+
+* Check that the USB device is detected by the OS.
+  VID/PID pair for ESP32-S2 is 303a:0002.
+
+  - On Windows, check the Device Manager
+  - On macOS, check USB section in the System Information utility
+  - On Linux, check `lsusb` output
+
+* If the device is not detected, check the USB cable connection (D+, D-, and ground should be connected)

examples/system/console_usb/main/CMakeLists.txt

@@ -0,0 +1,2 @@
+idf_component_register(SRCS "console_usb_example_main.c"
+                       INCLUDE_DIRS ".")

examples/system/console_usb/main/console_usb_example_main.c

@@ -0,0 +1,137 @@
+/* USB console example
+
+   This example code is in the Public Domain (or CC0 licensed, at your option.)
+
+   Unless required by applicable law or agreed to in writing, this
+   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+   CONDITIONS OF ANY KIND, either express or implied.
+*/
+
+#include <stdio.h>
+#include <string.h>
+#include <fcntl.h>
+#include "esp_system.h"
+#include "esp_log.h"
+#include "esp_console.h"
+#include "linenoise/linenoise.h"
+#include "argtable3/argtable3.h"
+#include "cmd_nvs.h"
+#include "cmd_system.h"
+#include "esp_vfs_cdcacm.h"
+#include "nvs.h"
+#include "nvs_flash.h"
+
+static void initialize_nvs(void)
+{
+    esp_err_t err = nvs_flash_init();
+    if (err == ESP_ERR_NVS_NO_FREE_PAGES || err == ESP_ERR_NVS_NEW_VERSION_FOUND) {
+        ESP_ERROR_CHECK( nvs_flash_erase() );
+        err = nvs_flash_init();
+    }
+    ESP_ERROR_CHECK(err);
+}
+
+static void initialize_console(void)
+{
+    /* Disable buffering on stdin */
+    setvbuf(stdin, NULL, _IONBF, 0);
+
+    /* Minicom, screen, idf_monitor send CR when ENTER key is pressed */
+    esp_vfs_dev_cdcacm_set_rx_line_endings(ESP_LINE_ENDINGS_CR);
+    /* Move the caret to the beginning of the next line on '\n' */
+    esp_vfs_dev_cdcacm_set_tx_line_endings(ESP_LINE_ENDINGS_CRLF);
+
+    /* Enable non-blocking mode on stdin and stdout */
+    fcntl(fileno(stdout), F_SETFL, 0);
+    fcntl(fileno(stdin), F_SETFL, 0);
+
+    /* Initialize the console */
+    esp_console_config_t console_config = {
+            .max_cmdline_args = 8,
+            .max_cmdline_length = 256,
+#if CONFIG_LOG_COLORS
+            .hint_color = atoi(LOG_COLOR_CYAN)
+#endif
+    };
+    ESP_ERROR_CHECK( esp_console_init(&console_config) );
+
+    /* Configure linenoise line completion library */
+    /* Enable multiline editing. If not set, long commands will scroll within
+     * single line.
+     */
+    linenoiseSetMultiLine(1);
+
+    /* Tell linenoise where to get command completions and hints */
+    linenoiseSetCompletionCallback(&esp_console_get_completion);
+    linenoiseSetHintsCallback((linenoiseHintsCallback*) &esp_console_get_hint);
+
+    /* Set command history size */
+    linenoiseHistorySetMaxLen(10);
+}
+
+void app_main(void)
+{
+    initialize_nvs();
+
+    initialize_console();
+
+    /* Register commands */
+    esp_console_register_help_command();
+    register_system_common();
+    register_nvs();
+
+    /* Prompt to be printed before each line.
+     * This can be customized, made dynamic, etc.
+     */
+    const char* prompt = LOG_COLOR_I CONFIG_IDF_TARGET "> " LOG_RESET_COLOR;
+
+    printf("\n"
+           "This is an example of ESP-IDF console component.\n"
+           "Type 'help' to get the list of commands.\n"
+           "Use UP/DOWN arrows to navigate through command history.\n"
+           "Press TAB when typing command name to auto-complete.\n");
+
+    /* Figure out if the terminal supports escape sequences */
+    int probe_status = linenoiseProbe();
+    if (probe_status) { /* zero indicates success */
+        printf("\n"
+               "Your terminal application does not support escape sequences.\n"
+               "Line editing and history features are disabled.\n"
+               "On Windows, try using Putty instead.\n");
+        linenoiseSetDumbMode(1);
+#if CONFIG_LOG_COLORS
+        /* Since the terminal doesn't support escape sequences,
+         * don't use color codes in the prompt.
+         */
+        prompt = CONFIG_IDF_TARGET "> ";
+#endif //CONFIG_LOG_COLORS
+    }
+
+    /* Main loop */
+    while(true) {
+        /* Get a line using linenoise.
+         * The line is returned when ENTER is pressed.
+         */
+        char* line = linenoise(prompt);
+        if (line == NULL) { /* Ignore empty lines */
+            continue;
+        }
+        /* Add the command to the history */
+        linenoiseHistoryAdd(line);
+
+        /* Try to run the command */
+        int ret;
+        esp_err_t err = esp_console_run(line, &ret);
+        if (err == ESP_ERR_NOT_FOUND) {
+            printf("Unrecognized command\n");
+        } else if (err == ESP_ERR_INVALID_ARG) {
+            // command was empty
+        } else if (err == ESP_OK && ret != ESP_OK) {
+            printf("Command returned non-zero error code: 0x%x (%s)\n", ret, esp_err_to_name(ret));
+        } else if (err != ESP_OK) {
+            printf("Internal error: %s\n", esp_err_to_name(err));
+        }
+        /* linenoise allocates line buffer on the heap, so need to free it */
+        linenoiseFree(line);
+    }
+}

examples/system/console_usb/sdkconfig.defaults

@@ -0,0 +1,13 @@
+# Build for ESP32-S2 by default
+CONFIG_IDF_TARGET="esp32s2"
+
+# Enable USB console
+CONFIG_ESP_CONSOLE_USB_CDC=y
+
+# Reduce bootloader log verbosity
+CONFIG_BOOTLOADER_LOG_LEVEL_WARN=y
+CONFIG_BOOTLOADER_LOG_LEVEL=2
+
+# Enable FreeRTOS stats formatting functions, needed for 'tasks' command
+CONFIG_FREERTOS_USE_TRACE_FACILITY=y
+CONFIG_FREERTOS_USE_STATS_FORMATTING_FUNCTIONS=y