driver(uart): Fix uart_get_baudrate incorrect return value when using ref_tick

components/driver/test/test_uart.c

@@ -0,0 +1,48 @@
+#include <string.h>
+#include "unity.h"
+#include "driver/uart.h"
+#include "esp_log.h"
+
+#define UART_TAG         "Uart"
+#define UART_NUM1        (UART_NUM_1)
+#define BUF_SIZE         (100)
+#define UART1_RX_PIN     (22)
+#define UART1_TX_PIN     (23)
+#define UART_BAUD_11520  (11520)
+#define UART_BAUD_115200 (115200)
+#define TOLERANCE        (0.02)    //baud rate error tolerance 2%.
+
+#define UART_TOLERANCE_CHECK(val, uper_limit, lower_limit)   ( (val) <= (uper_limit) && (val) >= (lower_limit) )
+
+static void uart_config(uint32_t baud_rate, bool use_ref_tick)
+{
+    uart_config_t uart_config = {
+        .baud_rate = baud_rate,
+        .data_bits = UART_DATA_8_BITS,
+        .parity = UART_PARITY_DISABLE,
+        .stop_bits = UART_STOP_BITS_1,
+        .flow_ctrl = UART_HW_FLOWCTRL_DISABLE,
+        .use_ref_tick = use_ref_tick,
+    };
+    uart_param_config(UART_NUM1, &uart_config);
+    uart_set_pin(UART_NUM1, UART1_TX_PIN, UART1_RX_PIN, UART_PIN_NO_CHANGE, UART_PIN_NO_CHANGE);
+    uart_driver_install(UART_NUM1, BUF_SIZE * 2, BUF_SIZE * 2, 20, NULL, 0);
+}
+
+TEST_CASE("test uart get baud-rate","[uart]")
+{
+    uint32_t baud_rate1 = 0;
+    uint32_t baud_rate2 = 0;
+    printf("init uart%d, use reftick, baud rate : %d\n", (int)UART_NUM1, (int)UART_BAUD_11520);
+    uart_config(UART_BAUD_11520, true);
+    uart_get_baudrate(UART_NUM1, &baud_rate1);
+    printf("init uart%d, unuse reftick, baud rate : %d\n", (int)UART_NUM1, (int)UART_BAUD_115200);
+    uart_config(UART_BAUD_115200, false);
+    uart_get_baudrate(UART_NUM1, &baud_rate2);
+    printf("get  baud rate when use reftick: %d\n", (int)baud_rate1);
+    printf("get  baud rate when don't use reftick: %d\n", (int)baud_rate2);
+    uart_driver_delete(UART_NUM1);
+    TEST_ASSERT(UART_TOLERANCE_CHECK(baud_rate1, (1.0 + TOLERANCE)*UART_BAUD_11520, (1.0 - TOLERANCE)*UART_BAUD_11520))
+    TEST_ASSERT(UART_TOLERANCE_CHECK(baud_rate2, (1.0 + TOLERANCE)*UART_BAUD_115200, (1.0 - TOLERANCE)*UART_BAUD_115200))
+    ESP_LOGI(UART_TAG, "get baud-rate test passed  ....\n");
+}

components/driver/uart.c

@@ -210,7 +210,11 @@ esp_err_t uart_get_baudrate(uart_port_t uart_num, uint32_t* baudrate)
     UART_ENTER_CRITICAL(&uart_spinlock[uart_num]);
     uint32_t clk_div = (UART[uart_num]->clk_div.div_int << 4) | UART[uart_num]->clk_div.div_frag;
     UART_EXIT_CRITICAL(&uart_spinlock[uart_num]);
-    (*baudrate) = ((UART_CLK_FREQ) << 4) / clk_div;
+    uint32_t uart_clk_freq = esp_clk_apb_freq();
+    if(UART[uart_num]->conf0.tick_ref_always_on == 0) {
+        uart_clk_freq = REF_CLK_FREQ;
+    }
+    (*baudrate) = ((uart_clk_freq) << 4) / clk_div;
     return ESP_OK;
 }