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From:   Chun-Kuang Hu <chunkuang.hu@kernel.org>
Date:   Tue, 6 Dec 2022 07:16:02 +0800
Message-ID: <CAAOTY__8uYdjFHGTrtq-ZTqvt7gaXeEKv9T3X0e=v4iZ52EE9g@mail.gmail.com>
Subject: Re: [PATCH v3] mailbox: mtk-cmdq: Do not request irq until we are ready
To:     Ricardo Ribalda <ribalda@chromium.org>
Cc:     Jassi Brar <jassisinghbrar@gmail.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-mediatek@lists.infradead.org
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Ricardo Ribalda <ribalda@chromium.org> =E6=96=BC 2022=E5=B9=B411=E6=9C=8830=
=E6=97=A5 =E9=80=B1=E4=B8=89 =E6=99=9A=E4=B8=8A8:59=E5=AF=AB=E9=81=93=EF=BC=
=9A
>
> If the system comes from kexec() the peripheral might trigger an IRQ
> befoe we are ready for it. Triggering a crash due to an access to
> invalid memory.

Reviewed-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>

>
> Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
> ---
> To: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> To: Jassi Brar <jassisinghbrar@gmail.com>
> To: Matthias Brugger <matthias.bgg@gmail.com>
> Cc: linux-kernel@vger.kernel.org
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-mediatek@lists.infradead.org
> ---
> Changes in v3:
> - Rebase on top of https://patchwork.kernel.org/project/linux-mediatek/pa=
tch/20221102100736.37815-1-angelogioacchino.delregno@collabora.com/
> - Link to v2: https://lore.kernel.org/r/20221125-mtk-mailbox-v2-0-886f70c=
7173c@chromium.org
>
> Changes in v2:
> - I have managed to repro a different panic. Moving the irq enabling to t=
he very end of probe.
> - Link to v1: https://lore.kernel.org/r/20221125-mtk-mailbox-v1-0-2e3ee12=
0850c@chromium.org
> ---
>  drivers/mailbox/mtk-cmdq-mailbox.c | 13 +++++++------
>  1 file changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/mailbox/mtk-cmdq-mailbox.c b/drivers/mailbox/mtk-cmd=
q-mailbox.c
> index a460ee26eb11..b18d47ea13a0 100644
> --- a/drivers/mailbox/mtk-cmdq-mailbox.c
> +++ b/drivers/mailbox/mtk-cmdq-mailbox.c
> @@ -569,12 +569,6 @@ static int cmdq_probe(struct platform_device *pdev)
>         }
>
>         cmdq->irq_mask =3D GENMASK(cmdq->pdata->thread_nr - 1, 0);
> -       err =3D devm_request_irq(dev, cmdq->irq, cmdq_irq_handler, IRQF_S=
HARED,
> -                              "mtk_cmdq", cmdq);
> -       if (err < 0) {
> -               dev_err(dev, "failed to register ISR (%d)\n", err);
> -               return err;
> -       }
>
>         dev_dbg(dev, "cmdq device: addr:0x%p, va:0x%p, irq:%d\n",
>                 dev, cmdq->base, cmdq->irq);
> @@ -641,6 +635,13 @@ static int cmdq_probe(struct platform_device *pdev)
>
>         cmdq_init(cmdq);
>
> +       err =3D devm_request_irq(dev, cmdq->irq, cmdq_irq_handler, IRQF_S=
HARED,
> +                              "mtk_cmdq", cmdq);
> +       if (err < 0) {
> +               dev_err(dev, "failed to register ISR (%d)\n", err);
> +               return err;
> +       }
> +
>         return 0;
>  }
>
>
> ---
> base-commit: 1642107db81361b4339643eb90af4839e2cf229f
> change-id: 20221125-mtk-mailbox-ba6cbd1d91b6
>
> Best regards,
> --
> Ricardo Ribalda <ribalda@chromium.org>
>