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uart: Add missing critical section wrappers around rx_buffered_len

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The missing barriers caused uart_get_buffered_data_len() to (very rarely)
return a garbage value. When used in MicroPython, though, this caused
select() to return and a subsequent read() to stall indefinitely until
a char was actually available.

Signed-off-by: Chen Yi Qun <chenyiqun@espressif.com>

Closes https://github.com/espressif/esp-idf/issues/6397
Merges https://github.com/espressif/esp-idf/pull/6396
This commit is contained in:
Omar Chebib
2021-08-16 17:32:14 +08:00
committed by Zim Kalinowski
parent 33a2927dab
commit abd6ea3087
1 changed files with 25 additions and 14 deletions
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15
components/driver/uart.c
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@@ -176,12 +176,14 @@ esp_err_t uart_set_stop_bits(uart_port_t uart_num, uart_stop_bits_t stop_bit)
esp_err_t uart_get_stop_bits(uart_port_t uart_num, uart_stop_bits_t* stop_bit) esp_err_t uart_get_stop_bits(uart_port_t uart_num, uart_stop_bits_t* stop_bit)
{ {
UART_CHECK((uart_num < UART_NUM_MAX), "uart_num error", ESP_FAIL); UART_CHECK((uart_num < UART_NUM_MAX), "uart_num error", ESP_FAIL);
UART_ENTER_CRITICAL(&uart_spinlock[uart_num]);
//workaround for hardware bug, when uart stop bit set as 2-bit mode. //workaround for hardware bug, when uart stop bit set as 2-bit mode.
if (UART[uart_num]->rs485_conf.dl1_en == 1 && UART[uart_num]->conf0.stop_bit_num == UART_STOP_BITS_1) { if (UART[uart_num]->rs485_conf.dl1_en == 1 && UART[uart_num]->conf0.stop_bit_num == UART_STOP_BITS_1) {
(*stop_bit) = UART_STOP_BITS_2; (*stop_bit) = UART_STOP_BITS_2;
} else { } else {
(*stop_bit) = UART[uart_num]->conf0.stop_bit_num; (*stop_bit) = UART[uart_num]->conf0.stop_bit_num;
} }
UART_EXIT_CRITICAL(&uart_spinlock[uart_num]);
return ESP_OK; return ESP_OK;
} }
@@ -198,6 +200,7 @@ esp_err_t uart_set_parity(uart_port_t uart_num, uart_parity_t parity_mode)
esp_err_t uart_get_parity(uart_port_t uart_num, uart_parity_t* parity_mode) esp_err_t uart_get_parity(uart_port_t uart_num, uart_parity_t* parity_mode)
{ {
UART_CHECK((uart_num < UART_NUM_MAX), "uart_num error", ESP_FAIL); UART_CHECK((uart_num < UART_NUM_MAX), "uart_num error", ESP_FAIL);
UART_ENTER_CRITICAL(&uart_spinlock[uart_num]);
int val = UART[uart_num]->conf0.val; int val = UART[uart_num]->conf0.val;
if(val & UART_PARITY_EN_M) { if(val & UART_PARITY_EN_M) {
if(val & UART_PARITY_M) { if(val & UART_PARITY_M) {
@@ -208,6 +211,7 @@ esp_err_t uart_get_parity(uart_port_t uart_num, uart_parity_t* parity_mode)
} else { } else {
(*parity_mode) = UART_PARITY_DISABLE; (*parity_mode) = UART_PARITY_DISABLE;
} }
UART_EXIT_CRITICAL(&uart_spinlock[uart_num]);
return ESP_OK; return ESP_OK;
} }
@@ -1302,7 +1306,9 @@ esp_err_t uart_get_buffered_data_len(uart_port_t uart_num, size_t* size)
{ {
UART_CHECK((uart_num < UART_NUM_MAX), "uart_num error", ESP_FAIL); UART_CHECK((uart_num < UART_NUM_MAX), "uart_num error", ESP_FAIL);
UART_CHECK((p_uart_obj[uart_num]), "uart driver error", ESP_FAIL); UART_CHECK((p_uart_obj[uart_num]), "uart driver error", ESP_FAIL);
UART_ENTER_CRITICAL(&uart_spinlock[uart_num]);
*size = p_uart_obj[uart_num]->rx_buffered_len; *size = p_uart_obj[uart_num]->rx_buffered_len;
UART_EXIT_CRITICAL(&uart_spinlock[uart_num]);
return ESP_OK; return ESP_OK;
} }
@@ -1332,14 +1338,19 @@ esp_err_t uart_flush_input(uart_port_t uart_num)
} }
data = (uint8_t*) xRingbufferReceive(p_uart->rx_ring_buf, &size, (portTickType) 0); data = (uint8_t*) xRingbufferReceive(p_uart->rx_ring_buf, &size, (portTickType) 0);
if(data == NULL) { if(data == NULL) {
bool error = false;
UART_ENTER_CRITICAL(&uart_spinlock[uart_num]);
if( p_uart_obj[uart_num]->rx_buffered_len != 0 ) { if( p_uart_obj[uart_num]->rx_buffered_len != 0 ) {
ESP_LOGE(UART_TAG, "rx_buffered_len error");
p_uart_obj[uart_num]->rx_buffered_len = 0; p_uart_obj[uart_num]->rx_buffered_len = 0;
error = true;
} }
//We also need to clear the `rx_buffer_full_flg` here. //We also need to clear the `rx_buffer_full_flg` here.
UART_ENTER_CRITICAL(&uart_spinlock[uart_num]);
p_uart_obj[uart_num]->rx_buffer_full_flg = false; p_uart_obj[uart_num]->rx_buffer_full_flg = false;
UART_EXIT_CRITICAL(&uart_spinlock[uart_num]); UART_EXIT_CRITICAL(&uart_spinlock[uart_num]);
if (error) {
// this must be called outside the critical section
ESP_LOGE(UART_TAG, "rx_buffered_len error");
}
break; break;
} }
UART_ENTER_CRITICAL(&uart_spinlock[uart_num]); UART_ENTER_CRITICAL(&uart_spinlock[uart_num]);