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serial: fsl_lpuart: disable DMA for console and fix sysrq 

SYSRQ doesn't work with DMA. This is because there is no error
indication whether a symbol had a framing error or not. Actually,
this is not completely correct, there is a bit in the data register
which is set in this case, but we'd have to read change the DMA access
to 16 bit and we'd need to post process the data, thus make the DMA
pointless in the first place.

Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20210512141255.18277-10-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Michael Walle 2021-05-12 16:12:55 +02:00 committed by Greg Kroah-Hartman
parent 8a0c810d94
commit 8cac2f6eb8
1 changed files with 6 additions and 0 deletions
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6
drivers/tty/serial/fsl_lpuart.c
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@ -1587,6 +1587,9 @@ static void lpuart_tx_dma_startup(struct lpuart_port *sport)
u32 uartbaud;
int ret;
if (uart_console(&sport->port))
goto err;
if (!sport->dma_tx_chan)
goto err;
@ -1616,6 +1619,9 @@ static void lpuart_rx_dma_startup(struct lpuart_port *sport)
int ret;
unsigned char cr3;
if (uart_console(&sport->port))
goto err;
if (!sport->dma_rx_chan)
goto err;