From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: MIME-Version: 1.0 In-Reply-To: <1465205633.25607.33.camel@mtksdaap41> References: <1464578397-29743-1-git-send-email-hs.liao@mediatek.com> <1464578397-29743-3-git-send-email-hs.liao@mediatek.com> <574C5CBF.7060002@gmail.com> <1464683762.14604.59.camel@mtksdaap41> <574DEE40.9010008@gmail.com> <1464775020.11122.40.camel@mtksdaap41> <574FF264.7050209@gmail.com> <1464934356.15175.31.camel@mtksdaap41> <57516774.5080008@gmail.com> <1465205633.25607.33.camel@mtksdaap41> From: Jassi Brar Date: Mon, 6 Jun 2016 18:47:02 +0530 Message-ID: Subject: Re: [PATCH v8 2/3] CMDQ: Mediatek CMDQ driver Content-Type: multipart/alternative; boundary=001a1147f4b27114d005349be3d8 To: Horng-Shyang Liao Cc: Jassi Brar , Matthias Brugger , Rob Herring , Daniel Kurtz , Sascha Hauer , Devicetree List , Linux Kernel Mailing List , "linux-arm-kernel@lists.infradead.org" , linux-mediatek@lists.infradead.org, srv_heupstream@mediatek.com, Sascha Hauer , Philipp Zabel , Nicolas Boichat , CK HU , cawa cheng , Bibby Hsieh , YT Shen , Daoyuan Huang , Damon Chu , Josh-YC Liu , Glory Hung , Jiaguang Zhang , Dennis-YC Hsieh , Monica Wang List-ID: --001a1147f4b27114d005349be3d8 Content-Type: text/plain; charset=UTF-8 On 6 June 2016 at 15:03, Horng-Shyang Liao wrote: > Hi Matthias, Jassi, > > On Fri, 2016-06-03 at 18:41 +0530, Jassi Brar wrote: > > On Fri, Jun 3, 2016 at 4:48 PM, Matthias Brugger > wrote: > > > On 03/06/16 08:12, Horng-Shyang Liao wrote: > > >> On Thu, 2016-06-02 at 10:46 +0200, Matthias Brugger wrote: > > > > >>> I keep thinking about how to get rid of the two data structures, > > >>> task_busy_list and the task_release_wq. We need the latter for the > only > > >>> sake of getting a timeout. > > >>> > > >>> Did you have a look on how the mailbox framework handles this? > > >>> By the way, what is the reason to not implement the whole driver as a > > >>> mailbox controller? For me, this driver looks like a good fit. > > >> > > >> > > >> CMDQ needs to encode commands for GCE hardware. We think this behavior > > >> should be put in CMDQ driver, and client just call CMDQ functions. > > >> Therefore, if we want to use mailbox framework, cmdq_rec must be > > >> mailbox client, and the others must be mailbox controller. > > >> > > > > > > You mean the functions to fill the cmdq_rec and execute it? > > > I think this should be part of the driver. > > > > > > Jassi, can you have a look on the interface this driver exports [0]. > > > They are needed to actually create the message which will be send. > > > Could something like this be part of a mailbox driver? > > > > > > [0] https://patchwork.kernel.org/patch/9140221/ > > > > > Packet creating/parsing should not be a part of controller driver. As > > the log of this patch says, today it is used for only display but in > > future it could work with other h/w as well, so it makes sense to have > > mailbox api do the message queuing, the controller driver do the > > send/receive and client drivers implement display and other h/w > > specific packaging of data (protocol handling). > > > > So yes, I think this could use mailbox api. > > > > Cheers. > > > Let me use display as an example to do some further explanation > about CMDQ in advance. You can think CMDQ is a shadow register > replacement. Therefore, we use cmdq_rec_write(_mask), cmdq_rec_wfe, and > cmdq_rec_clear_event instead of accessing registers, and use > cmdq_rec_flush(_async) instead of atomic swap. > > If we use mailbox to do the message queue, we can use mailbox framework > to implement flush and callback. However, I don't think mailbox is > suitable for cmdq_rec_write(_mask), cmdq_rec_wfe, and > cmdq_rec_clear_event since they are just record some commands. Is this > the same as your comment "Packet creating/parsing should not be a part > of controller driver."? > > Therefore, do you mean we use mailbox framework to implement flush and > callback and keep other interfaces? Yes, implement flush and callback in mailbox controller driver and keep other interfaces in mailbox client driver(s). Cheers. --001a1147f4b27114d005349be3d8 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable


On 6 June 2016 at 15:03, Horng-Shyang Liao <hs.liao@mediatek.com> wrote:
Hi Matthias, Jassi,
On Fri, 2016-06-03 at 18:41 +0530, Jassi Brar wrote:
> On Fri, Jun 3, 2016 at 4:48 PM, Matthias Brugger <matthias.bgg@gmail.com> wrote:
> > On 03/06/16 08:12, Horng-Shyang Liao wrote:
> >> On Thu, 2016-06-02 at 10:46 +0200, Matthias Brugger wrote: >
> >>> I keep thinking about how to get rid of the two data stru= ctures,
> >>> task_busy_list and the task_release_wq. We need the latte= r for the only
> >>> sake of getting a timeout.
> >>>
> >>> Did you have a look on how the mailbox framework handles = this?
> >>> By the way, what is the reason to not implement the whole= driver as a
> >>> mailbox controller? For me, this driver looks like a good= fit.
> >>
> >>
> >> CMDQ needs to encode commands for GCE hardware. We think this= behavior
> >> should be put in CMDQ driver, and client just call CMDQ funct= ions.
> >> Therefore, if we want to use mailbox framework, cmdq_rec must= be
> >> mailbox client, and the others must be mailbox controller. > >>
> >
> > You mean the functions to fill the cmdq_rec and execute it?
> > I think this should be part of the driver.
> >
> > Jassi, can you have a look on the interface this driver exports [= 0].
> > They are needed to actually create the message which will be send= .
> > Could something like this be part of a mailbox driver?
> >
> > [0] https://patchwork.kernel.org/patch/914022= 1/
> >
> Packet creating/parsing should not be a part of controller driver. As<= br> > the log of this patch says, today it is used for only display but in > future it could work with other h/w as well, so it makes sense to have=
> mailbox api do the message queuing, the controller driver do the
> send/receive and client drivers implement display and other h/w
> specific packaging of data (protocol handling).
>
> So yes, I think this could use mailbox api.
>
> Cheers.


Let me use display as an example to do some further explanation
about CMDQ in advance. You can think CMDQ is a shadow register
replacement. Therefore, we use cmdq_rec_write(_mask), cmdq_rec_wfe, and
cmdq_rec_clear_event instead of accessing registers, and use
cmdq_rec_flush(_async) instead of atomic swap.

If we use mailbox to do the message queue, we can use mailbox framework
to implement flush and callback. However, I don't think mailbox is
suitable for cmdq_rec_write(_mask), cmdq_rec_wfe, and
cmdq_rec_clear_event since they are just record some commands. Is this
the same as your comment "Packet creating/parsing should not be a part=
of controller driver."?

Therefore, do you mean we use mailbox framework to implement flush and
callback and keep other interfaces?

Yes, im= plement flush and callback in mailbox controller driver and keep other inte= rfaces in mailbox client driver(s).

Cheers.
<= /div>
--001a1147f4b27114d005349be3d8--