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From:   Chun-Kuang Hu <chunkuang.hu@kernel.org>
Date:   Fri, 20 Nov 2020 07:46:20 +0800
Message-ID: <CAAOTY_8c3WxPQ3igPojuF-3HbctQW0qiFM5GaqSuTDNcTSvvQA@mail.gmail.com>
Subject: Re: [PATCH v2] soc / drm: mediatek: cmdq: Remove timeout handler in
 helper function
To:     Chun-Kuang Hu <chunkuang.hu@kernel.org>
Cc:     Matthias Brugger <matthias.bgg@gmail.com>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        DRI Development <dri-devel@lists.freedesktop.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@lists.infradead.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>
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Hi, Matthias:

I've provided the example for why of this patch. How do you think
about this patch?

Regards,
Chun-Kuang.

Chun-Kuang Hu <chunkuang.hu@kernel.org> =E6=96=BC 2020=E5=B9=B411=E6=9C=882=
=E6=97=A5 =E9=80=B1=E4=B8=80 =E4=B8=8A=E5=8D=888:04=E5=AF=AB=E9=81=93=EF=BC=
=9A
>
> For each client driver, its timeout handler need to dump hardware registe=
r
> or its state machine information, and their way to detect timeout are
> also different, so remove timeout handler in helper function and
> let client driver implement its own timeout handler.
>
> Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
> ---
> v1 is one patch in series "Mediatek DRM driver detect CMDQ execution
> timeout by vblank IRQ", but according to Jassi's suggestion [1], send
> each patch in different series.
>
> [2] is an example that different client has different way to calculate
> timeout. Some client driver care about each packet's execution time, but
> some client driver care about the total execution time for all packets.
>
> [1]
> https://patchwork.kernel.org/project/linux-mediatek/cover/20200927230422.=
11610-1-chunkuang.hu@kernel.org/
> [2]
> https://patchwork.kernel.org/project/linux-mediatek/patch/20201022094152.=
17662-1-houlong.wei@mediatek.com/
>
> Changes in v2:
> 1. Rebase onto Linux 5.10-rc1
> ---
>  drivers/gpu/drm/mediatek/mtk_drm_crtc.c |  3 +-
>  drivers/soc/mediatek/mtk-cmdq-helper.c  | 41 +------------------------
>  include/linux/soc/mediatek/mtk-cmdq.h   | 10 +-----
>  3 files changed, 3 insertions(+), 51 deletions(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c b/drivers/gpu/drm/me=
diatek/mtk_drm_crtc.c
> index ac038572164d..4be5d1fccf2e 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> @@ -824,8 +824,7 @@ int mtk_drm_crtc_create(struct drm_device *drm_dev,
>  #if IS_REACHABLE(CONFIG_MTK_CMDQ)
>         mtk_crtc->cmdq_client =3D
>                         cmdq_mbox_create(mtk_crtc->mmsys_dev,
> -                                        drm_crtc_index(&mtk_crtc->base),
> -                                        2000);
> +                                        drm_crtc_index(&mtk_crtc->base))=
;
>         if (IS_ERR(mtk_crtc->cmdq_client)) {
>                 dev_dbg(dev, "mtk_crtc %d failed to create mailbox client=
, writing register by CPU now\n",
>                         drm_crtc_index(&mtk_crtc->base));
> diff --git a/drivers/soc/mediatek/mtk-cmdq-helper.c b/drivers/soc/mediate=
k/mtk-cmdq-helper.c
> index 505651b0d715..280d3bd9f675 100644
> --- a/drivers/soc/mediatek/mtk-cmdq-helper.c
> +++ b/drivers/soc/mediatek/mtk-cmdq-helper.c
> @@ -70,14 +70,7 @@ int cmdq_dev_get_client_reg(struct device *dev,
>  }
>  EXPORT_SYMBOL(cmdq_dev_get_client_reg);
>
> -static void cmdq_client_timeout(struct timer_list *t)
> -{
> -       struct cmdq_client *client =3D from_timer(client, t, timer);
> -
> -       dev_err(client->client.dev, "cmdq timeout!\n");
> -}
> -
> -struct cmdq_client *cmdq_mbox_create(struct device *dev, int index, u32 =
timeout)
> +struct cmdq_client *cmdq_mbox_create(struct device *dev, int index)
>  {
>         struct cmdq_client *client;
>
> @@ -85,12 +78,6 @@ struct cmdq_client *cmdq_mbox_create(struct device *de=
v, int index, u32 timeout)
>         if (!client)
>                 return (struct cmdq_client *)-ENOMEM;
>
> -       client->timeout_ms =3D timeout;
> -       if (timeout !=3D CMDQ_NO_TIMEOUT) {
> -               spin_lock_init(&client->lock);
> -               timer_setup(&client->timer, cmdq_client_timeout, 0);
> -       }
> -       client->pkt_cnt =3D 0;
>         client->client.dev =3D dev;
>         client->client.tx_block =3D false;
>         client->client.knows_txdone =3D true;
> @@ -112,11 +99,6 @@ EXPORT_SYMBOL(cmdq_mbox_create);
>
>  void cmdq_mbox_destroy(struct cmdq_client *client)
>  {
> -       if (client->timeout_ms !=3D CMDQ_NO_TIMEOUT) {
> -               spin_lock(&client->lock);
> -               del_timer_sync(&client->timer);
> -               spin_unlock(&client->lock);
> -       }
>         mbox_free_channel(client->chan);
>         kfree(client);
>  }
> @@ -449,18 +431,6 @@ static void cmdq_pkt_flush_async_cb(struct cmdq_cb_d=
ata data)
>         struct cmdq_task_cb *cb =3D &pkt->cb;
>         struct cmdq_client *client =3D (struct cmdq_client *)pkt->cl;
>
> -       if (client->timeout_ms !=3D CMDQ_NO_TIMEOUT) {
> -               unsigned long flags =3D 0;
> -
> -               spin_lock_irqsave(&client->lock, flags);
> -               if (--client->pkt_cnt =3D=3D 0)
> -                       del_timer(&client->timer);
> -               else
> -                       mod_timer(&client->timer, jiffies +
> -                                 msecs_to_jiffies(client->timeout_ms));
> -               spin_unlock_irqrestore(&client->lock, flags);
> -       }
> -
>         dma_sync_single_for_cpu(client->chan->mbox->dev, pkt->pa_base,
>                                 pkt->cmd_buf_size, DMA_TO_DEVICE);
>         if (cb->cb) {
> @@ -473,7 +443,6 @@ int cmdq_pkt_flush_async(struct cmdq_pkt *pkt, cmdq_a=
sync_flush_cb cb,
>                          void *data)
>  {
>         int err;
> -       unsigned long flags =3D 0;
>         struct cmdq_client *client =3D (struct cmdq_client *)pkt->cl;
>
>         pkt->cb.cb =3D cb;
> @@ -484,14 +453,6 @@ int cmdq_pkt_flush_async(struct cmdq_pkt *pkt, cmdq_=
async_flush_cb cb,
>         dma_sync_single_for_device(client->chan->mbox->dev, pkt->pa_base,
>                                    pkt->cmd_buf_size, DMA_TO_DEVICE);
>
> -       if (client->timeout_ms !=3D CMDQ_NO_TIMEOUT) {
> -               spin_lock_irqsave(&client->lock, flags);
> -               if (client->pkt_cnt++ =3D=3D 0)
> -                       mod_timer(&client->timer, jiffies +
> -                                 msecs_to_jiffies(client->timeout_ms));
> -               spin_unlock_irqrestore(&client->lock, flags);
> -       }
> -
>         err =3D mbox_send_message(client->chan, pkt);
>         if (err < 0)
>                 return err;
> diff --git a/include/linux/soc/mediatek/mtk-cmdq.h b/include/linux/soc/me=
diatek/mtk-cmdq.h
> index 960704d75994..8e9996610978 100644
> --- a/include/linux/soc/mediatek/mtk-cmdq.h
> +++ b/include/linux/soc/mediatek/mtk-cmdq.h
> @@ -11,7 +11,6 @@
>  #include <linux/mailbox/mtk-cmdq-mailbox.h>
>  #include <linux/timer.h>
>
> -#define CMDQ_NO_TIMEOUT                0xffffffffu
>  #define CMDQ_ADDR_HIGH(addr)   ((u32)(((addr) >> 16) & GENMASK(31, 0)))
>  #define CMDQ_ADDR_LOW(addr)    ((u16)(addr) | BIT(1))
>
> @@ -24,12 +23,8 @@ struct cmdq_client_reg {
>  };
>
>  struct cmdq_client {
> -       spinlock_t lock;
> -       u32 pkt_cnt;
>         struct mbox_client client;
>         struct mbox_chan *chan;
> -       struct timer_list timer;
> -       u32 timeout_ms; /* in unit of microsecond */
>  };
>
>  /**
> @@ -51,13 +46,10 @@ int cmdq_dev_get_client_reg(struct device *dev,
>   * cmdq_mbox_create() - create CMDQ mailbox client and channel
>   * @dev:       device of CMDQ mailbox client
>   * @index:     index of CMDQ mailbox channel
> - * @timeout:   timeout of a pkt execution by GCE, in unit of microsecond=
, set
> - *             CMDQ_NO_TIMEOUT if a timer is not used.
>   *
>   * Return: CMDQ mailbox client pointer
>   */
> -struct cmdq_client *cmdq_mbox_create(struct device *dev, int index,
> -                                    u32 timeout);
> +struct cmdq_client *cmdq_mbox_create(struct device *dev, int index);
>
>  /**
>   * cmdq_mbox_destroy() - destroy CMDQ mailbox client and channel
> --
> 2.17.1
>