[PATCH 5.10 066/157] serial: stm32: fix DMA initialization error handling

Greg Kroah-Hartman
2021-03-22T12:46:08Z

From: Erwan Le Ray <erwan.leray@foss.st.com>

[ Upstream commit e7997f7ff7f8154d477f6f976698d868a2ac3934 ]

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 '24832ca3ee85 ("tty: serial: stm32-usart: Remove set
but unused 'cookie' variables")' which unfortunately doesn't include a
"Fixes" tag.

Fixes: 3489187204eb ("serial: stm32: adding dma support")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210106162203.28854-2-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/tty/serial/stm32-usart.c | 24 +++++++++++++++++-------
1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index f4de32d3f2af..6248304a001f 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -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);
--
2.30.1