linux-kernel - Re: [PATCH v4 04/13] mailbox: mediatek: cmdq: clear task in channel before shutdown

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Message-ID: <1583289401.32049.2.camel@mtksdaap41>
Date:   Wed, 4 Mar 2020 10:36:41 +0800
From:   CK Hu <ck.hu@...iatek.com>
To:     Dennis YC Hsieh <dennis-yc.hsieh@...iatek.com>
CC:     Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Jassi Brar <jassisinghbrar@...il.com>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        "David Airlie" <airlied@...ux.ie>, Daniel Vetter <daniel@...ll.ch>,
        <linux-kernel@...r.kernel.org>,
        <linux-mediatek@...ts.infradead.org>, <devicetree@...r.kernel.org>,
        <wsd_upstream@...iatek.com>, <dri-devel@...ts.freedesktop.org>,
        Bibby Hsieh <bibby.hsieh@...iatek.com>,
        Houlong Wei <houlong.wei@...iatek.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        HS Liao <hs.liao@...iatek.com>
Subject: Re: [PATCH v4 04/13] mailbox: mediatek: cmdq: clear task in channel
 before shutdown

Hi, Dennis:

On Tue, 2020-03-03 at 18:58 +0800, Dennis YC Hsieh wrote:
> Do success callback in channel when shutdown. For those task not finish,
> callback with error code thus client has chance to cleanup or reset.
> 

Reviewed-by: CK Hu <ck.hu@...iatek.com>

> Signed-off-by: Dennis YC Hsieh <dennis-yc.hsieh@...iatek.com>
> ---
>  drivers/mailbox/mtk-cmdq-mailbox.c | 38 ++++++++++++++++++++++++++++++
>  1 file changed, 38 insertions(+)
> 
> diff --git a/drivers/mailbox/mtk-cmdq-mailbox.c b/drivers/mailbox/mtk-cmdq-mailbox.c
> index 9994ac9426d6..b56d340c8982 100644
> --- a/drivers/mailbox/mtk-cmdq-mailbox.c
> +++ b/drivers/mailbox/mtk-cmdq-mailbox.c
> @@ -387,6 +387,12 @@ static int cmdq_mbox_send_data(struct mbox_chan *chan, void *data)
>  
>  	if (list_empty(&thread->task_busy_list)) {
>  		WARN_ON(clk_enable(cmdq->clock) < 0);
> +		/*
> +		 * The thread reset will clear thread related register to 0,
> +		 * including pc, end, priority, irq, suspend and enable. Thus
> +		 * set CMDQ_THR_ENABLED to CMDQ_THR_ENABLE_TASK will enable
> +		 * thread and make it running.
> +		 */
>  		WARN_ON(cmdq_thread_reset(cmdq, thread) < 0);
>  
>  		writel(task->pa_base >> cmdq->shift_pa,
> @@ -450,6 +456,38 @@ static int cmdq_mbox_startup(struct mbox_chan *chan)
>  
>  static void cmdq_mbox_shutdown(struct mbox_chan *chan)
>  {
> +	struct cmdq_thread *thread = (struct cmdq_thread *)chan->con_priv;
> +	struct cmdq *cmdq = dev_get_drvdata(chan->mbox->dev);
> +	struct cmdq_task *task, *tmp;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&thread->chan->lock, flags);
> +	if (list_empty(&thread->task_busy_list))
> +		goto done;
> +
> +	WARN_ON(cmdq_thread_suspend(cmdq, thread) < 0);
> +
> +	/* make sure executed tasks have success callback */
> +	cmdq_thread_irq_handler(cmdq, thread);
> +	if (list_empty(&thread->task_busy_list))
> +		goto done;
> +
> +	list_for_each_entry_safe(task, tmp, &thread->task_busy_list,
> +				 list_entry) {
> +		cmdq_task_exec_done(task, CMDQ_CB_ERROR);
> +		kfree(task);
> +	}
> +
> +	cmdq_thread_disable(cmdq, thread);
> +	clk_disable(cmdq->clock);
> +done:
> +	/*
> +	 * The thread->task_busy_list empty means thread already disable. The
> +	 * cmdq_mbox_send_data() always reset thread which clear disable and
> +	 * suspend statue when first pkt send to channel, so there is no need
> +	 * to do any operation here, only unlock and leave.
> +	 */
> +	spin_unlock_irqrestore(&thread->chan->lock, flags);
>  }
>  
>  static const struct mbox_chan_ops cmdq_mbox_chan_ops = {