Re: FW: [PATCH v20 2/4] mailbox: mediatek: Add Mediatek CMDQ driver

From: houlong wei <houlong.wei@mediatek.com>
To: Jassi Brar <jassisinghbrar@gmail.com>
Cc: "Rob Herring" <robh+dt@kernel.org>,
	"Matthias Brugger" <matthias.bgg@gmail.com>,
	"Daniel Kurtz" <djkurtz@chromium.org>,
	"Sascha Hauer" <s.hauer@pengutronix.de>,
	"Devicetree List" <devicetree@vger.kernel.org>,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
	linux-mediatek@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	srv_heupstream <srv_heupstream@mediatek.com>,
	"Sascha Hauer" <kernel@pengutronix.de>,
	"Philipp Zabel" <p.zabel@pengutronix.de>,
	"Nicolas Boichat" <drinkcat@chromium.org>,
	"CK Hu (胡俊光)" <ck.hu@mediatek.com>,
	"Cawa Cheng (鄭曄禧)" <cawa.cheng@mediatek.com>,
	"Bibby Hsieh (謝濟遠)" <Bibby.Hsieh@mediatek.com>,
	"YT Shen (沈岳霆)" <Yt.Shen@mediatek.com>,
	"Daoyuan Huang (黃道原)" <Daoyuan.Huang@mediatek.com>,
	"Damon Chu (朱峻賢)" <Damon.Chu@mediatek.com>,
	"Josh-YC Liu (劉育誠)" <Josh-YC.Liu@mediatek.com>,
	"Glory Hung (洪智瑋)" <glory.hung@mediatek.com>,
	"Jiaguang Zhang (张加广)" <Jiaguang.Zhang@mediatek.com>,
	"Dennis-YC Hsieh (謝宇哲)" <Dennis-YC.Hsieh@mediatek.com>,
	"Monica Wang (王孟婷)" <monica.wang@mediatek.com>,
	"Hs Liao (廖宏祥)" <Hs.Liao@mediatek.com>,
	houlong.wei@mediatek.com
Subject: Re: FW: [PATCH v20 2/4] mailbox: mediatek: Add Mediatek CMDQ driver
Date: Thu, 18 Jan 2018 16:31:53 +0800	[thread overview]
Message-ID: <1516264313.16602.30.camel@mhfsdcap03> (raw)
In-Reply-To: <CABb+yY02S=+00mY-NTkJUBPiVruYdf0xuovKomehUxLNOQPLuA@mail.gmail.com>

Hi Jassi,

There is one request for one GCE h/w buffer which contains a list of
registers operation.
I will resubmit a version and please review again.

Thanks,
Houlong

On Thu, 2018-01-18 at 16:01 +0800, Jassi Brar wrote:
> On Mon, Jan 8, 2018 at 2:08 PM, houlong wei <houlong.wei@mediatek.com> wrote:
> > Hi Jassi,
> >
> > Sorry for reply so late.
> > According to previous discussion, there are two methods to move
> > dma_map_single() outside of spin_lock.
> > (1) put in mtk-cmdq-helper.c, as described by HS on 2017-02-09.
> >   > I think a trade-off solution is to put in mtk-cmdq-helper.c.
> >   > Although it is a mailbox client, it is not a CMDQ client.
> >   > We can include mailbox_controller.h in mtk-cmdq-helper.c (instead of
> > mtk-cmdq.h), and then map dma at cmdq_pkt_flush_async before
> > mbox_send_message.
> >
> >   > pkt->pa_base = dma_map_single(client->chan->mbox->dev, pkt->va_base,
> >   >                              pkt->cmd_buf_size, DMA_TO_DEVICE);
> > (2) schedule a tasklet in send_data().
> >
> > After internal discussion with HS and other experts, now we prefer
> > method (1).
> > How do you think about it?
> >
> I don't exactly see how you mean but please remember send_data()
> callback is supposed to be atomic ... it is protected by
> spin_lock_irqsave/restore in drivers/mailbox/mailbox.c:msg_submit()
> 
> BTW, how many requests max can be queued in the GCE h/w buffer?
> And since it's been over a year now, could you please resubmit after
> checking for checkpatch with the --strict option?
> 
> Thanks.