linux-kernel - Re: [PATCH v3 8/9] mailbox: mediatek: Add CMDQ secure mailbox driver

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Message-ID: <fdd275452f99e3fa1b1b98be05151121858dcc60.camel@mediatek.com>
Date: Thu, 4 Jan 2024 05:42:17 +0000
From: CK Hu (胡俊光) <ck.hu@...iatek.com>
To: "jassisinghbrar@...il.com" <jassisinghbrar@...il.com>,
	"matthias.bgg@...il.com" <matthias.bgg@...il.com>,
	Jason-JH Lin (林睿祥) <Jason-JH.Lin@...iatek.com>,
	"angelogioacchino.delregno@...labora.com"
	<angelogioacchino.delregno@...labora.com>, "robh+dt@...nel.org"
	<robh+dt@...nel.org>, "krzysztof.kozlowski+dt@...aro.org"
	<krzysztof.kozlowski+dt@...aro.org>, "chunkuang.hu@...nel.org"
	<chunkuang.hu@...nel.org>
CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-mediatek@...ts.infradead.org" <linux-mediatek@...ts.infradead.org>,
	Singo Chang (張興國) <Singo.Chang@...iatek.com>,
	Johnson Wang (王聖鑫) <Johnson.Wang@...iatek.com>,
	"linux-media@...r.kernel.org" <linux-media@...r.kernel.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	Jason-ch Chen (陳建豪)
	<Jason-ch.Chen@...iatek.com>, Shawn Sung (宋孝謙)
	<Shawn.Sung@...iatek.com>, "mchehab@...nel.org" <mchehab@...nel.org>,
	Nancy Lin (林欣螢) <Nancy.Lin@...iatek.com>,
	"conor+dt@...nel.org" <conor+dt@...nel.org>,
	Project_Global_Chrome_Upstream_Group
	<Project_Global_Chrome_Upstream_Group@...iatek.com>,
	"linux-arm-kernel@...ts.infradead.org" <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v3 8/9] mailbox: mediatek: Add CMDQ secure mailbox driver

Hi, Jason:

On Wed, 2024-01-03 at 07:03 +0000, Jason-JH Lin (林睿祥) wrote:
> On Thu, 2023-12-28 at 07:37 +0000, CK Hu (胡俊光) wrote:
> > Hi, Jason:
> > 
> > On Fri, 2023-12-22 at 12:52 +0800, Jason-JH.Lin wrote:
> > > To support secure video path feature, GCE have to read/write
> > > registgers
> > > in the secure world. GCE will enable the secure access permission
> > > to
> > > the
> > > HW who wants to access the secure content buffer.
> > > 
> > > Add CMDQ secure mailbox driver to make CMDQ client user is able
> > > to
> > > sending their HW settings to the secure world. So that GCE can
> > > execute
> > > all instructions to configure HW in the secure world.
> > > 
> > > Signed-off-by: Jason-JH.Lin <jason-jh.lin@...iatek.com>
> > > ---
> > 
> > [snip]
> > 
> > > +
> > > +static bool cmdq_sec_irq_handler(struct cmdq_sec_thread
> > > *sec_thread,
> > > +				 const u32 cookie, const int err)
> > > +{
> > > +	struct cmdq_sec_task *sec_task;
> > > +	struct cmdq_task *task, *temp, *cur_task = NULL;
> > > +	struct cmdq_sec *cmdq = container_of(sec_thread->thread.chan-
> > > > mbox, struct cmdq_sec, mbox);
> > > 
> > > +	unsigned long flags;
> > > +	int done;
> > > +
> > > +	spin_lock_irqsave(&sec_thread->thread.chan->lock, flags);
> > > +	if (sec_thread->wait_cookie <= cookie)
> > > +		done = cookie - sec_thread->wait_cookie + 1;
> > > +	else if (sec_thread->wait_cookie == (cookie + 1) %
> > > CMDQ_MAX_COOKIE_VALUE)
> > > +		done = 0;
> > > +	else
> > > +		done = CMDQ_MAX_COOKIE_VALUE - sec_thread->wait_cookie
> > > + 1 + cookie + 1;
> > > +
> > > +	list_for_each_entry_safe(task, temp, &sec_thread-
> > > > thread.task_busy_list, list_entry) {
> > > 
> > > +		if (!done)
> > > +			break;
> > > +
> > > +		sec_task = container_of(task, struct cmdq_sec_task,
> > > task);
> > > +		cmdq_sec_task_done(sec_task, err);
> > > +
> > > +		if (sec_thread->task_cnt)
> > > +			sec_thread->task_cnt -= 1;
> > > +
> > > +		done--;
> > > +	}
> > > +
> > > +	cur_task = list_first_entry_or_null(&sec_thread-
> > > > thread.task_busy_list,
> > > 
> > > +					    struct cmdq_task,
> > > list_entry);
> > > +	if (err && cur_task) {
> > > +		spin_unlock_irqrestore(&sec_thread->thread.chan->lock,
> > > flags);
> > > +
> > > +		sec_task = container_of(cur_task, struct cmdq_sec_task,
> > > task);
> > > +
> > > +		/* for error task, cancel, callback and done */
> > > +		memset(&cmdq->cancel, 0, sizeof(cmdq->cancel));
> > > +		cmdq_sec_task_submit(cmdq, sec_task,
> > > CMD_CMDQ_IWC_CANCEL_TASK,
> > > +				     sec_thread->idx, &cmdq->cancel);
> > 
> > cmdq->cancel is useless, so drop it.
> > 
> > Regards,
> > CK
> > 
> 
> I think we should use this to tell CMDQ PTA which thread need to
> reset
> and update its cookie value, so CMDQ can still move on when error
> occurs.

CMD_CMDQ_IWC_CANCEL_TASK is used to tell CMDQ PTA which thread need to
reset and update its cookie value, and cmdq->cancel is the return value. But you does not process this return value, so drop cmdq->cancel.

Regards,
CK

> 
> Regards,
> Jason-JH.Lin