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HAL_ChibiOS: added a timeout to DMA UART TX

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this prevents a shared DMA channel being held for a long time if a CTS
pin is held either by not being connected or by a radio
This commit is contained in:
Andrew Tridgell 2018-06-17 21:16:04 +10:00
parent cad7f9d9c0
commit 8431a677d9
2 changed files with 26 additions and 0 deletions
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24
libraries/AP_HAL_ChibiOS/UARTDriver.cpp
View File

@ -169,6 +169,7 @@ void UARTDriver::begin(uint32_t b, uint16_t rxS, uint16_t txS)
}
if (tx_bounce_buf == nullptr) {
tx_bounce_buf = (uint8_t *)hal.util->malloc_type(TX_BOUNCE_BUFSIZE, AP_HAL::Util::MEM_DMA_SAFE);
chVTObjectInit(&tx_timeout);
tx_bounce_buf_ready = true;
}
@ -324,6 +325,11 @@ void UARTDriver::tx_complete(void* self, uint32_t flags)
{
UARTDriver* uart_drv = (UARTDriver*)self;
if (!uart_drv->tx_bounce_buf_ready) {
// reset timeout
chSysLockFromISR();
chVTResetI(&uart_drv->tx_timeout);
chSysUnlockFromISR();
uart_drv->_last_write_completed_us = AP_HAL::micros();
uart_drv->tx_bounce_buf_ready = true;
if (uart_drv->unbuffered_writes && uart_drv->_writebuf.available()) {
@ -602,6 +608,7 @@ void UARTDriver::check_dma_tx_completion(void)
if (txdma->stream->NDTR == 0) {
tx_bounce_buf_ready = true;
_last_write_completed_us = AP_HAL::micros();
chVTResetI(&tx_timeout);
dma_handle->unlock_from_lockzone();
}
}
@ -609,6 +616,21 @@ void UARTDriver::check_dma_tx_completion(void)
chSysUnlock();
}
/*
handle a TX timeout. This can happen with using hardware flow
control if CTS pin blocks transmit
*/
void UARTDriver::handle_tx_timeout(void *arg)
{
UARTDriver* uart_drv = (UARTDriver*)arg;
if (!uart_drv->tx_bounce_buf_ready) {
uart_drv->tx_len = 0; // fix for n sent
dmaStreamDisable(uart_drv->txdma);
uart_drv->tx_bounce_buf_ready = true;
uart_drv->dma_handle->unlock_from_IRQ();
}
}
/*
write out pending bytes with DMA
*/
@ -653,6 +675,8 @@ void UARTDriver::write_pending_bytes_DMA(uint32_t n)
dmaStreamSetMode(txdma, dmamode | STM32_DMA_CR_DIR_M2P |
STM32_DMA_CR_MINC | STM32_DMA_CR_TCIE);
dmaStreamEnable(txdma);
uint32_t timeout_us = ((1000000UL * (tx_len+2) * 10) / _baudrate) + 500;
chVTSet(&tx_timeout, US2ST(timeout_us), handle_tx_timeout, this);
}
/*

2
libraries/AP_HAL_ChibiOS/UARTDriver.h
View File

@ -138,6 +138,7 @@ private:
Semaphore _write_mutex;
const stm32_dma_stream_t* rxdma;
const stm32_dma_stream_t* txdma;
virtual_timer_t tx_timeout;
bool _in_timer;
bool _blocking_writes;
bool _initialised;
@ -162,6 +163,7 @@ private:
static void rx_irq_cb(void* sd);
static void rxbuff_full_irq(void* self, uint32_t flags);
static void tx_complete(void* self, uint32_t flags);
static void handle_tx_timeout(void *arg);
void dma_tx_allocate(Shared_DMA *ctx);
void dma_tx_deallocate(Shared_DMA *ctx);