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samd/machine_uart: Simplify machine_uart_any() and machine_uart_read().

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Remove the call to uart_drain_rx_fifo().  It is not required, and may cause
a race condition.
This commit is contained in:
robert-hh 2022-11-19 22:23:02 +01:00 committed by Damien George
parent 4199f986ad
commit 5b1fd8802a
1 changed files with 0 additions and 8 deletions
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8
ports/samd/machine_uart.c
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@ -362,8 +362,6 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_uart_deinit_obj, machine_uart_deinit);
STATIC mp_obj_t machine_uart_any(mp_obj_t self_in) { STATIC mp_obj_t machine_uart_any(mp_obj_t self_in) {
machine_uart_obj_t *self = MP_OBJ_TO_PTR(self_in); machine_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
// get all bytes from the fifo first. May be obsolete.
uart_drain_rx_fifo(self, sercom_instance[self->id]);
return MP_OBJ_NEW_SMALL_INT(ringbuf_avail(&self->read_buffer)); return MP_OBJ_NEW_SMALL_INT(ringbuf_avail(&self->read_buffer));
} }
STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_uart_any_obj, machine_uart_any); STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_uart_any_obj, machine_uart_any);
@ -431,16 +429,10 @@ STATIC mp_uint_t machine_uart_read(mp_obj_t self_in, void *buf_in, mp_uint_t siz
uint64_t t = mp_hal_ticks_ms_64() + self->timeout; uint64_t t = mp_hal_ticks_ms_64() + self->timeout;
uint64_t timeout_char = self->timeout_char; uint64_t timeout_char = self->timeout_char;
uint8_t *dest = buf_in; uint8_t *dest = buf_in;
Sercom *uart = sercom_instance[self->id];
for (size_t i = 0; i < size; i++) { for (size_t i = 0; i < size; i++) {
// Wait for the first/next character // Wait for the first/next character
while (ringbuf_avail(&self->read_buffer) == 0) { while (ringbuf_avail(&self->read_buffer) == 0) {
if (uart->USART.INTFLAG.bit.RXC != 0) {
// Force a few incoming bytes to the buffer
uart_drain_rx_fifo(self, uart);
break;
}
if (mp_hal_ticks_ms_64() > t) { // timed out if (mp_hal_ticks_ms_64() > t) { // timed out
if (i <= 0) { if (i <= 0) {
*errcode = MP_EAGAIN; *errcode = MP_EAGAIN;