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SubjectRe: [PATCH 1/3] tty: serial: fsl_lpuart: move dev_info_once()
Am 2020-03-24 19:47, schrieb Michael Walle:
> Don't take the spinlock and use dev_info_once(). This may cause a hang
> because the console takes this spinlock, too. Just print this info
> after
> we've released the lock.
>
> Fixes: 159381df1442f ("tty: serial: fsl_lpuart: fix DMA operation when
> using IOMMU")
> Reported-by: Leonard Crestez <leonard.crestez@nxp.com>
> Signed-off-by: Michael Walle <michael@walle.cc>

Because the patch subject was renamed: This patch series is superseded
by the v2:

https://lore.kernel.org/linux-serial/20200325090658.25967-1-michael@walle.cc/

I didn't include the 3/3 RFC patch though. This is a bigger change,
which
should be carefully reviewed by the maintainer of the fsl_lpuart.c.

-michael


> ---
> drivers/tty/serial/fsl_lpuart.c | 22 +++++++++++++++-------
> 1 file changed, 15 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/tty/serial/fsl_lpuart.c
> b/drivers/tty/serial/fsl_lpuart.c
> index 9c6a018b1390..960fc2658f19 100644
> --- a/drivers/tty/serial/fsl_lpuart.c
> +++ b/drivers/tty/serial/fsl_lpuart.c
> @@ -1517,9 +1517,6 @@ static void lpuart_tx_dma_startup(struct
> lpuart_port *sport)
>
> sport->dma_tx_chan = dma_request_chan(sport->port.dev, "tx");
> if (IS_ERR(sport->dma_tx_chan)) {
> - dev_info_once(sport->port.dev,
> - "DMA tx channel request failed, operating without tx DMA
> (%ld)\n",
> - PTR_ERR(sport->dma_tx_chan));
> sport->dma_tx_chan = NULL;
> goto err;
> }
> @@ -1551,9 +1548,6 @@ static void lpuart_rx_dma_startup(struct
> lpuart_port *sport)
>
> sport->dma_rx_chan = dma_request_chan(sport->port.dev, "rx");
> if (IS_ERR(sport->dma_rx_chan)) {
> - dev_info_once(sport->port.dev,
> - "DMA rx channel request failed, operating without rx DMA
> (%ld)\n",
> - PTR_ERR(sport->dma_rx_chan));
> sport->dma_rx_chan = NULL;
> goto err;
> }
> @@ -1601,6 +1595,13 @@ static int lpuart_startup(struct uart_port
> *port)
>
> spin_unlock_irqrestore(&sport->port.lock, flags);
>
> + if (!sport->dma_rx_chan)
> + dev_info_once(sport->port.dev,
> + "DMA rx channel request failed, operating without rx DMA\n");
> + if (!sport->dma_tx_chan)
> + dev_info_once(sport->port.dev,
> + "DMA tx channel request failed, operating without tx DMA\n");
> +
> return 0;
> }
>
> @@ -1653,13 +1654,20 @@ static int lpuart32_startup(struct uart_port
> *port)
>
> lpuart32_setup_watermark_enable(sport);
>
> -
> lpuart_rx_dma_startup(sport);
> lpuart_tx_dma_startup(sport);
>
> lpuart32_configure(sport);
>
> spin_unlock_irqrestore(&sport->port.lock, flags);
> +
> + if (!sport->dma_rx_chan)
> + dev_info_once(sport->port.dev,
> + "DMA rx channel request failed, operating without rx DMA\n");
> + if (!sport->dma_tx_chan)
> + dev_info_once(sport->port.dev,
> + "DMA tx channel request failed, operating without tx DMA\n");
> +
> return 0;
> }

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