From: Tudor Ambarus tudor.ambarus@microchip.com
stable inclusion from stable-v5.10.94 commit f93c9aa1d36f594b065c93d8bd17151d21fe02d8 bugzilla: https://gitee.com/openeuler/kernel/issues/I531X9
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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[ Upstream commit 4f4b9b5895614eb2e2b5f4cab7858f44bd113e1b ]
The driver wrongly assummed that tx_submit() will start the transfer, which is not the case, now that the at_xdmac driver is fixed. tx_submit is supposed to push the current transaction descriptor to a pending queue, waiting for issue_pending to be called. issue_pending must start the transfer, not tx_submit.
Fixes: 34df42f59a60 ("serial: at91: add rx dma support") Fixes: 08f738be88bb ("serial: at91: add tx dma support") Signed-off-by: Tudor Ambarus tudor.ambarus@microchip.com Link: https://lore.kernel.org/r/20211125090028.786832-4-tudor.ambarus@microchip.co... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Acked-by: Xie XiuQi xiexiuqi@huawei.com --- drivers/tty/serial/atmel_serial.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c index 396fe8c51f93..602065bfc9bb 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -1009,6 +1009,8 @@ static void atmel_tx_dma(struct uart_port *port) atmel_port->cookie_tx); return; } + + dma_async_issue_pending(chan); }
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) @@ -1275,6 +1277,8 @@ static int atmel_prepare_rx_dma(struct uart_port *port) goto chan_err; }
+ dma_async_issue_pending(atmel_port->chan_rx); + return 0;
chan_err: