Commit e7997f7f authored by Erwan Le Ray's avatar Erwan Le Ray Committed by Greg Kroah-Hartman
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serial: stm32: fix DMA initialization error handling 



DMA initialization error handling is not properly implemented in the
driver.
Fix DMA initialization error handling by:
- moving TX DMA descriptor request error handling in a new dedicated
fallback_err label
- adding error handling to TX DMA descriptor submission
- adding error handling to RX DMA descriptor submission

This patch depends on '24832ca3 ("tty: serial: stm32-usart: Remove set
but unused 'cookie' variables")' which unfortunately doesn't include a
"Fixes" tag.

Fixes: 34891872 ("serial: stm32: adding dma support")
Signed-off-by: default avatarErwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210106162203.28854-2-erwan.leray@foss.st.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent c762a2b8

drivers/tty/serial/stm32-usart.c

+17 −7
Original line number Diff line number Diff line
@@ -383,17 +383,18 @@ static void stm32_transmit_chars_dma(struct uart_port *port) 
					   DMA_MEM_TO_DEV,

					   DMA_PREP_INTERRUPT);



	if (!desc) {

		for (i = count; i > 0; i--)

			stm32_transmit_chars_pio(port);

		return;

	}

	if (!desc)

		goto fallback_err;



	desc->callback = stm32_tx_dma_complete;

	desc->callback_param = port;



	/* Push current DMA TX transaction in the pending queue */

	dmaengine_submit(desc);

	if (dma_submit_error(dmaengine_submit(desc))) {

		/* dma no yet started, safe to free resources */

		dmaengine_terminate_async(stm32port->tx_ch);

		goto fallback_err;

	}



	/* Issue pending DMA TX requests */

	dma_async_issue_pending(stm32port->tx_ch);
@@ -402,6 +403,11 @@ static void stm32_transmit_chars_dma(struct uart_port *port) 


	xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);

	port->icount.tx += count;

	return;



fallback_err:

	for (i = count; i > 0; i--)

		stm32_transmit_chars_pio(port);

}



static void stm32_transmit_chars(struct uart_port *port)
@@ -1130,7 +1136,11 @@ static int stm32_of_dma_rx_probe(struct stm32_port *stm32port, 
	desc->callback_param = NULL;



	/* Push current DMA transaction in the pending queue */

	dmaengine_submit(desc);

	ret = dma_submit_error(dmaengine_submit(desc));

	if (ret) {

		dmaengine_terminate_sync(stm32port->rx_ch);

		goto config_err;

	}



	/* Issue pending DMA requests */

	dma_async_issue_pending(stm32port->rx_ch);