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HAL_ChibiOS: prevent hw flow control from hogging a DMA channel

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When hw flow control is enabled check the CTS pin before we grab the
DMA channel to prevent a long timeout trying to send to a blocked port
from holding a DMA channel against another device

this fixes issue #16587
This commit is contained in:
Andrew Tridgell 2021-02-11 09:11:44 +11:00
parent ee8e9e3289
commit 9de1519928
3 changed files with 18 additions and 3 deletions
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13
libraries/AP_HAL_ChibiOS/UARTDriver.cpp
View File

@ -829,6 +829,19 @@ void UARTDriver::write_pending_bytes_DMA(uint32_t n)
if (tx_len == 0) {
return;
}
if (_flow_control != FLOW_CONTROL_DISABLE &&
sdef.cts_line != 0 &&
palReadLine(sdef.cts_line)) {
// we are using hw flow control and the CTS line is high. We
// will hold off trying to transmit until the CTS line goes
// low to indicate the receiver has space. We do this before
// we take the DMA lock to prevent a high CTS line holding a
// DMA channel that may be needed by another device
tx_len = 0;
return;
}
if (!dma_handle->lock_nonblock()) {
tx_len = 0;
return;

1
libraries/AP_HAL_ChibiOS/UARTDriver.h
View File

@ -81,6 +81,7 @@ public:
ioline_t tx_line;
ioline_t rx_line;
ioline_t rts_line;
ioline_t cts_line;
int8_t rxinv_gpio;
uint8_t rxinv_polarity;
int8_t txinv_gpio;

7
libraries/AP_HAL_ChibiOS/hwdef/scripts/chibios_hwdef.py
View File

@ -1214,6 +1214,7 @@ def write_UART_config(f):
tx_line = make_line(dev + '_TX')
rx_line = make_line(dev + '_RX')
rts_line = make_line(dev + '_RTS')
cts_line = make_line(dev + '_CTS')
if rts_line != "0":
have_rts_cts = True
f.write('#define HAL_HAVE_RTSCTS_SERIAL%u\n' % uart_serial_num[dev])
@ -1234,10 +1235,10 @@ def write_UART_config(f):
"#define HAL_%s_CONFIG { (BaseSequentialStream*) &SD%u, %u, false, "
% (dev, n, n))
if mcu_series.startswith("STM32F1"):
f.write("%s, %s, %s, " % (tx_line, rx_line, rts_line))
f.write("%s, %s, %s, %s, " % (tx_line, rx_line, rts_line, cts_line))
else:
f.write("STM32_%s_RX_DMA_CONFIG, STM32_%s_TX_DMA_CONFIG, %s, %s, %s, " %
(dev, dev, tx_line, rx_line, rts_line))
f.write("STM32_%s_RX_DMA_CONFIG, STM32_%s_TX_DMA_CONFIG, %s, %s, %s, %s, " %
(dev, dev, tx_line, rx_line, rts_line, cts_line))
# add inversion pins, if any
f.write("%d, " % get_gpio_bylabel(dev + "_RXINV"))