linux-kernel - Re: [PATCH v4 2/4] spi: spi-fsl-dspi: Fix lockup if device is shutdown during SPI transfer

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Date:   Mon, 22 Jun 2020 14:17:50 +0300
From:   Vladimir Oltean <olteanv@...il.com>
To:     Krzysztof Kozlowski <krzk@...nel.org>
Cc:     Mark Brown <broonie@...nel.org>, Peng Ma <peng.ma@....com>,
        linux-spi <linux-spi@...r.kernel.org>,
        lkml <linux-kernel@...r.kernel.org>,
        Vladimir Oltean <vladimir.oltean@....com>,
        Wolfram Sang <wsa@...nel.org>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        stable@...r.kernel.org
Subject: Re: [PATCH v4 2/4] spi: spi-fsl-dspi: Fix lockup if device is
 shutdown during SPI transfer

On Mon, 22 Jun 2020 at 14:08, Krzysztof Kozlowski <krzk@...nel.org> wrote:
>
> During shutdown, the driver should unregister the SPI controller
> and stop the hardware.  Otherwise the dspi_transfer_one_message() could
> wait on completion infinitely.
>
> Additionally, calling spi_unregister_controller() first in device
> shutdown reverse-matches the probe function, where SPI controller is
> registered at the end.
>
> Fixes: dc234825997e ("spi: spi-fsl-dspi: Adding shutdown hook")
> Cc: <stable@...r.kernel.org>
> Reported-by: Vladimir Oltean <olteanv@...il.com>
> Signed-off-by: Krzysztof Kozlowski <krzk@...nel.org>
>
> ---

Reviewed-by: Vladimir Oltean <vladimir.oltean@....com>
Tested-by: Vladimir Oltean <vladimir.oltean@....com>

>
> kexec() not tested, only system shutdown.
>
> Changes since v3:
> 1. New patch.
> ---
>  drivers/spi/spi-fsl-dspi.c | 15 +--------------
>  1 file changed, 1 insertion(+), 14 deletions(-)
>
> diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
> index ec0fd0d366eb..ec7919d9c0d9 100644
> --- a/drivers/spi/spi-fsl-dspi.c
> +++ b/drivers/spi/spi-fsl-dspi.c
> @@ -1452,20 +1452,7 @@ static int dspi_remove(struct platform_device *pdev)
>
>  static void dspi_shutdown(struct platform_device *pdev)
>  {
> -       struct spi_controller *ctlr = platform_get_drvdata(pdev);
> -       struct fsl_dspi *dspi = spi_controller_get_devdata(ctlr);
> -
> -       /* Disable RX and TX */
> -       regmap_update_bits(dspi->regmap, SPI_MCR,
> -                          SPI_MCR_DIS_TXF | SPI_MCR_DIS_RXF,
> -                          SPI_MCR_DIS_TXF | SPI_MCR_DIS_RXF);
> -
> -       /* Stop Running */
> -       regmap_update_bits(dspi->regmap, SPI_MCR, SPI_MCR_HALT, SPI_MCR_HALT);
> -
> -       dspi_release_dma(dspi);
> -       clk_disable_unprepare(dspi->clk);
> -       spi_unregister_controller(dspi->ctlr);
> +       dspi_remove(pdev);
>  }
>
>  static struct platform_driver fsl_dspi_driver = {
> --
> 2.17.1
>