Add uart_read_some_bytes() to allow reading into a buffer without waiting until that buffer is full (IDFGH-16435)

components/esp_driver_uart/include/driver/uart.h

@@ -556,6 +556,7 @@ int uart_write_bytes_with_break(uart_port_t uart_num, const void* src, size_t si
 
 /**
  * @brief UART read bytes from UART buffer
+ * Blocks until the buffer to fill is filled completely or timeout is expired
  *
  * @param uart_num UART port number, the max port number is (UART_NUM_MAX -1).
  * @param buf     pointer to the buffer.
@@ -568,6 +569,21 @@ int uart_write_bytes_with_break(uart_port_t uart_num, const void* src, size_t si
  */
 int uart_read_bytes(uart_port_t uart_num, void* buf, uint32_t length, TickType_t ticks_to_wait);
 
+/**
+ * @brief UART read bytes from UART buffer
+ * Blocks until there is at least something to read (might be smaller than length!) or timeout is expired
+ *
+ * @param uart_num UART port number, the max port number is (UART_NUM_MAX -1).
+ * @param buf     pointer to the buffer.
+ * @param length  data length
+ * @param ticks_to_wait sTimeout, count in RTOS ticks
+ *
+ * @return
+ *     - (-1) Error
+ *     - OTHERS (>=0) The number of bytes read from UART buffer
+ */
+int uart_read_some_bytes(uart_port_t uart_num, void* buf, uint32_t length, TickType_t ticks_to_wait);
+
 /**
  * @brief Alias of uart_flush_input.
  *        UART ring buffer flush. This will discard all data in the UART RX buffer.

components/esp_driver_uart/src/uart.c

@@ -1653,6 +1653,34 @@ int uart_read_bytes(uart_port_t uart_num, void *buf, uint32_t length, TickType_t
     return copy_len;
 }
 
+int uart_read_some_bytes(uart_port_t uart_num, void *buf, uint32_t length, TickType_t ticks_to_wait)
+{
+    ESP_RETURN_ON_FALSE((uart_num < UART_NUM_MAX), (-1), UART_TAG, "uart_num error");
+    ESP_RETURN_ON_FALSE((buf), (-1), UART_TAG, "uart data null");
+    ESP_RETURN_ON_FALSE((p_uart_obj[uart_num]), (-1), UART_TAG, "uart driver error");
+    uint8_t *data = NULL;
+    size_t size = 0;
+    if (xSemaphoreTake(p_uart_obj[uart_num]->rx_mux, (TickType_t)ticks_to_wait) != pdTRUE) {
+        return -1;
+    }
+
+    data = (uint8_t *) xRingbufferReceiveUpTo(p_uart_obj[uart_num]->rx_ring_buf, &size, (TickType_t) ticks_to_wait, length);
+    if (!data) {
+        xSemaphoreGive(p_uart_obj[uart_num]->rx_mux);
+        return 0;
+    }
+    memcpy((uint8_t *)buf, data, size);
+    UART_ENTER_CRITICAL(&(uart_context[uart_num].spinlock));
+    p_uart_obj[uart_num]->rx_buffered_len -= size;
+    uart_pattern_queue_update(uart_num, size);
+    UART_EXIT_CRITICAL(&(uart_context[uart_num].spinlock));
+    vRingbufferReturnItem(p_uart_obj[uart_num]->rx_ring_buf, data);
+    uart_check_buf_full(uart_num);
+
+    xSemaphoreGive(p_uart_obj[uart_num]->rx_mux);
+    return size;
+}
+
 esp_err_t uart_get_buffered_data_len(uart_port_t uart_num, size_t *size)
 {
     ESP_RETURN_ON_FALSE((uart_num < UART_NUM_MAX), ESP_FAIL, UART_TAG, "uart_num error");