linux-kernel - Re: [PATCH v2 3/3] mailbox: mediatek: Add mtk-apu-mailbox driver

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Message-ID: <CABb+yY0FHBxvc2Lwg9O1G9O+rxoXk-tS1QFwi63=_zsV0SyYuw@mail.gmail.com>
Date: Sun, 12 Jan 2025 11:02:30 -0600
From: Jassi Brar <jassisinghbrar@...il.com>
To: Chen-Yu Tsai <wenst@...omium.org>
Cc: "Karl.Li" <karl.li@...iatek.com>, Rob Herring <robh@...nel.org>, 
	Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
	Matthias Brugger <matthias.bgg@...il.com>, 
	AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>, linux-kernel@...r.kernel.org, 
	devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	linux-mediatek@...ts.infradead.org, Chungying Lu <chungying.lu@...iatek.com>, 
	Chien-Chih Tseng <Chien-Chih.Tseng@...iatek.com>, Andy Teng <Andy.Teng@...iatek.com>, 
	Project_Global_Chrome_Upstream_Group@...iatek.com
Subject: Re: [PATCH v2 3/3] mailbox: mediatek: Add mtk-apu-mailbox driver

On Thu, Jan 2, 2025 at 10:56 PM Chen-Yu Tsai <wenst@...omium.org> wrote:
>
> On Fri, Jan 3, 2025 at 12:30 PM Jassi Brar <jassisinghbrar@...il.com> wrote:
> >
> > On Sun, Dec 29, 2024 at 9:46 PM Karl.Li <karl.li@...iatek.com> wrote:
> > ....
> > > +
> > > +static irqreturn_t mtk_apu_mailbox_irq(int irq, void *data)
> > > +{
> > > +       struct mbox_chan *chan = data;
> > > +       struct mtk_apu_mailbox *apu_mbox = get_mtk_apu_mailbox(chan->mbox);
> > > +       struct mbox_chan *link = &apu_mbox->mbox.chans[0];
> > > +       u8 data_cnt = fls(readl(apu_mbox->regs + MTK_APU_MBOX_OUTBOX_IRQ));
> > > +
> > > +       memcpy_fromio(apu_mbox->msgs.data, apu_mbox->regs + MTK_APU_MBOX_OUTBOX,
> > > +                     sizeof(*apu_mbox->msgs.data) * data_cnt);
> > > +
> > > +       mbox_chan_received_data(link, apu_mbox->msgs.data);
> > > +
> > > +       return IRQ_WAKE_THREAD;
> > > +}
> > > +
> > You don't seem to do anything that 'ack' the irq line. So if you merge
> > this into mtk_apu_mailbox_irq_thread() and do
> >  devm_request_threaded_irq(dev, irq,   NULL,
> > mtk_apu_mailbox_irq_thread,  IRQF_ONESHOT,  ...);
> > you can avoid adding a new api and keep your client code simple.
> > mbox_chan_received_data() is strictly between the client and
> > controller driver. If it is not called from an atomic context, feel
> > free to do memcpy() from it.
>
> That sounds great. Could we perhaps update the API documentation and
> drop the "atomic" requirement, or update it to something you describe
> here as "between the client and controller driver".
>
Not drop, but simply add a line that the client needs to respect the
context in which the controller does the callback.

thanks