Re: [PATCH v4 3/4] spi: spi-fsl-dspi: Fix external abort on interrupt in resume or exit paths

[Vladimir Oltean <olteanv@gmail.com>]

On Mon, 22 Jun 2020 at 14:07, Krzysztof Kozlowski <krzk@kernel.org> wrote:
>
> If shared interrupt comes late, during probe error path or device remove
> (could be triggered with CONFIG_DEBUG_SHIRQ), the interrupt handler
> dspi_interrupt() will access registers with the clock being disabled.
> This leads to external abort on non-linefetch on Toradex Colibri VF50
> module (with Vybrid VF5xx):
>
>     $ echo 4002d000.spi > /sys/devices/platform/soc/40000000.bus/4002d000.spi/driver/unbind
>
>     Unhandled fault: external abort on non-linefetch (0x1008) at 0x8887f02c
>     Internal error: : 1008 [#1] ARM
>     Hardware name: Freescale Vybrid VF5xx/VF6xx (Device Tree)
>     Backtrace:
>       (regmap_mmio_read32le)
>       (regmap_mmio_read)
>       (_regmap_bus_reg_read)
>       (_regmap_read)
>       (regmap_read)
>       (dspi_interrupt)
>       (free_irq)
>       (devm_irq_release)
>       (release_nodes)
>       (devres_release_all)
>       (device_release_driver_internal)
>
> The resource-managed framework should not be used for shared interrupt
> handling, because the interrupt handler might be called after releasing
> other resources and disabling clocks.
>
> Similar bug could happen during suspend - the shared interrupt handler
> could be invoked after suspending the device.  Each device sharing this
> interrupt line should disable the IRQ during suspend so handler will be
> invoked only in following cases:
> 1. None suspended,
> 2. All devices resumed.
>
> Fixes: 349ad66c0ab0 ("spi:Add Freescale DSPI driver for Vybrid VF610 platform")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
>
> ---

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

>
> Changes since v3:
> 1. Use simpler if (dspi->irq).
>
> Changes since v2:
> 1. Go back to v1 and use non-devm interface,
> 2. Fix also suspend/resume paths.
>
> Changes since v1:
> 1. Disable the IRQ instead of using non-devm interface.
> ---
>  drivers/spi/spi-fsl-dspi.c | 17 +++++++++++++----
>  1 file changed, 13 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
> index ec7919d9c0d9..e0b30e4b1b69 100644
> --- a/drivers/spi/spi-fsl-dspi.c
> +++ b/drivers/spi/spi-fsl-dspi.c
> @@ -1109,6 +1109,8 @@ static int dspi_suspend(struct device *dev)
>         struct spi_controller *ctlr = dev_get_drvdata(dev);
>         struct fsl_dspi *dspi = spi_controller_get_devdata(ctlr);
>
> +       if (dspi->irq)
> +               disable_irq(dspi->irq);
>         spi_controller_suspend(ctlr);
>         clk_disable_unprepare(dspi->clk);
>
> @@ -1129,6 +1131,8 @@ static int dspi_resume(struct device *dev)
>         if (ret)
>                 return ret;
>         spi_controller_resume(ctlr);
> +       if (dspi->irq)
> +               enable_irq(dspi->irq);
>
>         return 0;
>  }
> @@ -1385,8 +1389,8 @@ static int dspi_probe(struct platform_device *pdev)
>                 goto poll_mode;
>         }
>
> -       ret = devm_request_irq(&pdev->dev, dspi->irq, dspi_interrupt,
> -                              IRQF_SHARED, pdev->name, dspi);
> +       ret = request_threaded_irq(dspi->irq, dspi_interrupt, NULL,
> +                                  IRQF_SHARED, pdev->name, dspi);
>         if (ret < 0) {
>                 dev_err(&pdev->dev, "Unable to attach DSPI interrupt\n");
>                 goto out_clk_put;
> @@ -1400,7 +1404,7 @@ static int dspi_probe(struct platform_device *pdev)
>                 ret = dspi_request_dma(dspi, res->start);
>                 if (ret < 0) {
>                         dev_err(&pdev->dev, "can't get dma channels\n");
> -                       goto out_clk_put;
> +                       goto out_free_irq;
>                 }
>         }
>
> @@ -1415,11 +1419,14 @@ static int dspi_probe(struct platform_device *pdev)
>         ret = spi_register_controller(ctlr);
>         if (ret != 0) {
>                 dev_err(&pdev->dev, "Problem registering DSPI ctlr\n");
> -               goto out_clk_put;
> +               goto out_free_irq;
>         }
>
>         return ret;
>
> +out_free_irq:
> +       if (dspi->irq)
> +               free_irq(dspi->irq, dspi);
>  out_clk_put:
>         clk_disable_unprepare(dspi->clk);
>  out_ctlr_put:
> @@ -1445,6 +1452,8 @@ static int dspi_remove(struct platform_device *pdev)
>         regmap_update_bits(dspi->regmap, SPI_MCR, SPI_MCR_HALT, SPI_MCR_HALT);
>
>         dspi_release_dma(dspi);
> +       if (dspi->irq)
> +               free_irq(dspi->irq, dspi);
>         clk_disable_unprepare(dspi->clk);
>
>         return 0;
> --
> 2.17.1
>