stm32/uart: Factor out code from machine_uart.c that computes baudrate.

ports/stm32/machine_uart.c

@@ -245,46 +245,7 @@ STATIC mp_obj_t pyb_uart_init_helper(pyb_uart_obj_t *self, size_t n_args, const
     }
 
     // compute actual baudrate that was configured
-    // (this formula assumes UART_OVERSAMPLING_16)
-    uint32_t actual_baudrate = 0;
-    #if defined(STM32F0)
-    actual_baudrate = HAL_RCC_GetPCLK1Freq();
-    #elif defined(STM32F7) || defined(STM32H7)
-    UART_ClockSourceTypeDef clocksource = UART_CLOCKSOURCE_UNDEFINED;
-    UART_GETCLOCKSOURCE(&self->uart, clocksource);
-    switch (clocksource) {
-        #if defined(STM32H7)
-        case UART_CLOCKSOURCE_D2PCLK1: actual_baudrate = HAL_RCC_GetPCLK1Freq(); break;
-        case UART_CLOCKSOURCE_D3PCLK1: actual_baudrate = HAL_RCC_GetPCLK1Freq(); break;
-        case UART_CLOCKSOURCE_D2PCLK2: actual_baudrate = HAL_RCC_GetPCLK2Freq(); break;
-        #else
-        case UART_CLOCKSOURCE_PCLK1:  actual_baudrate = HAL_RCC_GetPCLK1Freq(); break;
-        case UART_CLOCKSOURCE_PCLK2:  actual_baudrate = HAL_RCC_GetPCLK2Freq(); break;
-        case UART_CLOCKSOURCE_SYSCLK: actual_baudrate = HAL_RCC_GetSysClockFreq(); break;
-        #endif
-        #if defined(STM32H7)
-        case UART_CLOCKSOURCE_CSI:    actual_baudrate = CSI_VALUE; break;
-        #endif
-        case UART_CLOCKSOURCE_HSI:    actual_baudrate = HSI_VALUE; break;
-        case UART_CLOCKSOURCE_LSE:    actual_baudrate = LSE_VALUE; break;
-        #if defined(STM32H7)
-        case UART_CLOCKSOURCE_PLL2:
-        case UART_CLOCKSOURCE_PLL3:
-        #endif
-        case UART_CLOCKSOURCE_UNDEFINED: break;
-    }
-    #else
-    if (self->uart.Instance == USART1
-        #if defined(USART6)
-        || self->uart.Instance == USART6
-        #endif
-        ) {
-        actual_baudrate = HAL_RCC_GetPCLK2Freq();
-    } else {
-        actual_baudrate = HAL_RCC_GetPCLK1Freq();
-    }
-    #endif
-    actual_baudrate /= self->uart.Instance->BRR;
+    uint32_t actual_baudrate = uart_get_baudrate(self);
 
     // check we could set the baudrate within 5%
     uint32_t baudrate_diff;

ports/stm32/uart.c

@@ -406,6 +406,53 @@ bool uart_init(pyb_uart_obj_t *uart_obj, uint32_t baudrate) {
 }
 */
 
+uint32_t uart_get_baudrate(pyb_uart_obj_t *self) {
+    uint32_t uart_clk = 0;
+
+    #if defined(STM32F0)
+    uart_clk = HAL_RCC_GetPCLK1Freq();
+    #elif defined(STM32F7) || defined(STM32H7)
+    UART_ClockSourceTypeDef clocksource = UART_CLOCKSOURCE_UNDEFINED;
+    UART_GETCLOCKSOURCE(&self->uart, clocksource);
+    switch (clocksource) {
+        #if defined(STM32H7)
+        case UART_CLOCKSOURCE_D2PCLK1: uart_clk = HAL_RCC_GetPCLK1Freq(); break;
+        case UART_CLOCKSOURCE_D3PCLK1: uart_clk = HAL_RCC_GetPCLK1Freq(); break;
+        case UART_CLOCKSOURCE_D2PCLK2: uart_clk = HAL_RCC_GetPCLK2Freq(); break;
+        #else
+        case UART_CLOCKSOURCE_PCLK1:  uart_clk = HAL_RCC_GetPCLK1Freq(); break;
+        case UART_CLOCKSOURCE_PCLK2:  uart_clk = HAL_RCC_GetPCLK2Freq(); break;
+        case UART_CLOCKSOURCE_SYSCLK: uart_clk = HAL_RCC_GetSysClockFreq(); break;
+        #endif
+        #if defined(STM32H7)
+        case UART_CLOCKSOURCE_CSI:    uart_clk = CSI_VALUE; break;
+        #endif
+        case UART_CLOCKSOURCE_HSI:    uart_clk = HSI_VALUE; break;
+        case UART_CLOCKSOURCE_LSE:    uart_clk = LSE_VALUE; break;
+        #if defined(STM32H7)
+        case UART_CLOCKSOURCE_PLL2:
+        case UART_CLOCKSOURCE_PLL3:
+        #endif
+        case UART_CLOCKSOURCE_UNDEFINED: break;
+    }
+    #else
+    if (self->uart.Instance == USART1
+        #if defined(USART6)
+        || self->uart.Instance == USART6
+        #endif
+        ) {
+        uart_clk = HAL_RCC_GetPCLK2Freq();
+    } else {
+        uart_clk = HAL_RCC_GetPCLK1Freq();
+    }
+    #endif
+
+    // This formula assumes UART_OVERSAMPLING_16
+    uint32_t baudrate = uart_clk / self->uart.Instance->BRR;
+
+    return baudrate;
+}
+
 mp_uint_t uart_rx_any(pyb_uart_obj_t *self) {
     int buffer_bytes = self->read_buf_head - self->read_buf_tail;
     if (buffer_bytes < 0) {

ports/stm32/uart.h

@@ -68,6 +68,7 @@ void uart_deinit(pyb_uart_obj_t *uart_obj);
 void uart_irq_handler(mp_uint_t uart_id);
 
 void uart_attach_to_repl(pyb_uart_obj_t *self, bool attached);
+uint32_t uart_get_baudrate(pyb_uart_obj_t *self);
 mp_uint_t uart_rx_any(pyb_uart_obj_t *uart_obj);
 bool uart_rx_wait(pyb_uart_obj_t *self, uint32_t timeout);
 int uart_rx_char(pyb_uart_obj_t *uart_obj);