linux-kernel - Re: [PATCH v1] mailbox: cmdq: add instruction time-out interrupt support

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Date:   Sat, 17 Jul 2021 00:42:43 +0800
From:   Chun-Kuang Hu <chunkuang.hu@...nel.org>
To:     Yongqiang Niu <yongqiang.niu@...iatek.com>
Cc:     Chun-Kuang Hu <chunkuang.hu@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Jassi Brar <jassisinghbrar@...il.com>,
        Fabien Parent <fparent@...libre.com>,
        Dennis YC Hsieh <dennis-yc.hsieh@...iatek.com>,
        DTML <devicetree@...r.kernel.org>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@...ts.infradead.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        DRI Development <dri-devel@...ts.freedesktop.org>,
        Project_Global_Chrome_Upstream_Group@...iatek.com,
        Hsin-Yi Wang <hsinyi@...omium.org>
Subject: Re: [PATCH v1] mailbox: cmdq: add instruction time-out interrupt support

Hi, Yongqiang:

Yongqiang Niu <yongqiang.niu@...iatek.com> 於 2021年7月16日 週五 下午2:58寫道：
>
> add time-out cycle setting to make sure time-out interrupt irq
> will happened when instruction time-out for wait and poll
>
> Signed-off-by: Yongqiang Niu <yongqiang.niu@...iatek.com>
> ---
>  drivers/mailbox/mtk-cmdq-mailbox.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
>
> diff --git a/drivers/mailbox/mtk-cmdq-mailbox.c b/drivers/mailbox/mtk-cmdq-mailbox.c
> index de4793e..9a76bcd 100644
> --- a/drivers/mailbox/mtk-cmdq-mailbox.c
> +++ b/drivers/mailbox/mtk-cmdq-mailbox.c
> @@ -35,6 +35,7 @@
>  #define CMDQ_THR_END_ADDR              0x24
>  #define CMDQ_THR_WAIT_TOKEN            0x30
>  #define CMDQ_THR_PRIORITY              0x40
> +#define CMDQ_THR_INSTN_TIMEOUT_CYCLES  0x50
>
>  #define GCE_GCTL_VALUE                 0x48
>
> @@ -53,6 +54,15 @@
>  #define CMDQ_JUMP_BY_OFFSET            0x10000000
>  #define CMDQ_JUMP_BY_PA                        0x10000001
>
> +/*
> + * instruction time-out
> + * cycles to issue instruction time-out interrupt for wait and poll instructions
> + * GCE axi_clock 156MHz
> + * 1 cycle = 6.41ns
> + * instruction time out 2^22*2*6.41ns = 53ms

I think every client has different timeout value, so it's not a good
idea to have a unique timeout value in mailbox controller. Client
could use timer or something similar to detect timeout.

Regards,
Chun-Kuang.

> + */
> +#define CMDQ_INSTN_TIMEOUT_CYCLES      22
> +
>  struct cmdq_thread {
>         struct mbox_chan        *chan;
>         void __iomem            *base;
> @@ -368,6 +378,7 @@ static int cmdq_mbox_send_data(struct mbox_chan *chan, void *data)
>                 writel((task->pa_base + pkt->cmd_buf_size) >> cmdq->shift_pa,
>                        thread->base + CMDQ_THR_END_ADDR);
>
> +               writel(CMDQ_INSTN_TIMEOUT_CYCLES, thread->base + CMDQ_THR_INSTN_TIMEOUT_CYCLES);
>                 writel(thread->priority, thread->base + CMDQ_THR_PRIORITY);
>                 writel(CMDQ_THR_IRQ_EN, thread->base + CMDQ_THR_IRQ_ENABLE);
>                 writel(CMDQ_THR_ENABLED, thread->base + CMDQ_THR_ENABLE_TASK);
> --
> 1.8.1.1.dirty
>