For esp_restart API, reset uart0 core first, then reset uart0 apb side, so as to prevent uart output garbage after cpu reset. (UART0 RST bits will be cleared in ROM)

Add UART0/1 core reset on esp32c3, in case uart driver would also reset uart hardwares.

components/esp_system/port/soc/esp32c3/system_internal.c

@@ -30,6 +30,7 @@
 #include "soc/rtc_periph.h"
 #include "soc/syscon_reg.h"
 #include "soc/system_reg.h"
+#include "soc/uart_reg.h"
 #include "hal/wdt_hal.h"
 #include "cache_err_int.h"
 
@@ -103,6 +104,10 @@ void IRAM_ATTR esp_restart_noos(void)
 
     REG_WRITE(SYSTEM_CORE_RST_EN_REG, 0);
 
+    // Reset uart0 core first, then reset apb side.
+    // rom will clear this bit, as well as SYSTEM_UART_RST
+    SET_PERI_REG_MASK(UART_CLK_CONF_REG(0), UART_RST_CORE_M);
+
     // Reset timer/spi/uart
     SET_PERI_REG_MASK(SYSTEM_PERIP_RST_EN0_REG,
                       SYSTEM_TIMERS_RST | SYSTEM_SPI01_RST | SYSTEM_UART_RST);

components/hal/esp32c3/include/hal/clk_gate_ll.h

@@ -24,6 +24,7 @@ extern "C" {
 #include "soc/system_reg.h"
 #include "soc/syscon_reg.h"
 #include "soc/dport_access.h"
+#include "soc/uart_reg.h"
 
 static inline uint32_t periph_ll_get_clk_en_mask(periph_module_t periph)
 {
@@ -208,6 +209,12 @@ static inline void periph_ll_enable_clk_clear_rst(periph_module_t periph)
 
 static inline void periph_ll_disable_clk_set_rst(periph_module_t periph)
 {
+    // set UART_RST_CORE before setting SYSTEM_UART_RST on esp32c3
+    if (periph == PERIPH_UART0_MODULE) {
+        SET_PERI_REG_MASK(UART_CLK_CONF_REG(0), UART_RST_CORE_M);
+    } else if (periph == PERIPH_UART1_MODULE) {
+        SET_PERI_REG_MASK(UART_CLK_CONF_REG(1), UART_RST_CORE_M);
+    }
     DPORT_CLEAR_PERI_REG_MASK(periph_ll_get_clk_en_reg(periph), periph_ll_get_clk_en_mask(periph));
     DPORT_SET_PERI_REG_MASK(periph_ll_get_rst_en_reg(periph), periph_ll_get_rst_en_mask(periph, false));
 }
@@ -226,6 +233,12 @@ static inline void IRAM_ATTR periph_ll_wifi_bt_module_disable_clk_set_rst(void)
 
 static inline void periph_ll_reset(periph_module_t periph)
 {
+    // set UART_RST_CORE before setting SYSTEM_UART_RST on esp32c3
+    if (periph == PERIPH_UART0_MODULE) {
+        SET_PERI_REG_MASK(UART_CLK_CONF_REG(0), UART_RST_CORE_M);
+    } else if (periph == PERIPH_UART1_MODULE) {
+        SET_PERI_REG_MASK(UART_CLK_CONF_REG(1), UART_RST_CORE_M);
+    }
     DPORT_SET_PERI_REG_MASK(periph_ll_get_rst_en_reg(periph), periph_ll_get_rst_en_mask(periph, false));
     DPORT_CLEAR_PERI_REG_MASK(periph_ll_get_rst_en_reg(periph), periph_ll_get_rst_en_mask(periph, false));
 }