linux-kernel - Re: [PATCHv10 2/4] mailbox: Introduce framework for mailbox

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Message-ID: <CAJ5Y-eZDHuHJpbZ8owYosR3gmqfEtTJeeMB_B_z6dxda+QyNnw@mail.gmail.com>
Date:	Fri, 26 Sep 2014 11:43:26 -0400
From:	Ashwin Chaugule <ashwin.chaugule@...aro.org>
To:	Jassi Brar <jaswinder.singh@...aro.org>
Cc:	Sudeep Holla <sudeep.holla@....com>,
	Devicetree List <devicetree@...r.kernel.org>,
	lkml <linux-kernel@...r.kernel.org>,
	"ks.giri@...sung.com" <ks.giri@...sung.com>,
	Arnd Bergmann <arnd@...db.de>,
	"ijc+devicetree@...lion.org.uk" <ijc+devicetree@...lion.org.uk>,
	Mark Rutland <Mark.Rutland@....com>,
	Rob Herring <robh+dt@...nel.org>,
	Pawel Moll <Pawel.Moll@....com>,
	Courtney Cavin <courtney.cavin@...ymobile.com>,
	Matt Porter <mporter@...aro.org>,
	Craig McGeachie <slapdau@...oo.com.au>,
	LeyFoon Tan <lftan.linux@...il.com>,
	Loic Pallardy <loic.pallardy@...com>,
	"Anna, Suman" <s-anna@...com>, Bjorn Andersson <bjorn@...o.se>,
	Patch Tracking <patches@...aro.org>,
	"mollie.wu@...aro.org" <mollie.wu@...aro.org>,
	Tetsuya Takinishi <t.takinishi@...fujitsu.com>,
	"broonie@...aro.org" <broonie@...aro.org>,
	Kevin Hilman <khilman@...aro.org>,
	"lee.jones@...aro.org" <lee.jones@...aro.org>,
	"andy.green@...aro.org" <andy.green@...aro.org>
Subject: Re: [PATCHv10 2/4] mailbox: Introduce framework for mailbox

On 25 September 2014 20:57, Jassi Brar <jaswinder.singh@...aro.org> wrote:
> On 24 September 2014 09:14, Ashwin Chaugule <ashwin.chaugule@...aro.org> wrote:
>> On 22 September 2014 14:33, Sudeep Holla <sudeep.holla@....com> wrote:
>
>>>>>> +static void poll_txdone(unsigned long data)
>>>>>> +{
>>>>>> +       struct mbox_controller *mbox = (struct mbox_controller *)data;
>>>>>> +       bool txdone, resched = false;
>>>>>> +       int i;
>>>>>> +
>>>>>> +       for (i = 0; i < mbox->num_chans; i++) {
>>>>>> +               struct mbox_chan *chan = &mbox->chans[i];
>>>>>> +
>>>>>> +               if (chan->active_req && chan->cl) {
>>>>>> +                       resched = true;
>>>>>> +                       txdone = chan->mbox->ops->last_tx_done(chan);
>>>>>> +                       if (txdone)
>>>>>> +                               tx_tick(chan, 0);
>>>>>> +               }
>>>>>> +       }
>>>>>> +
>>>>>> +       if (resched)
>>>>>> +               mod_timer(&mbox->poll, jiffies +
>>>>>> +                               msecs_to_jiffies(mbox->period));
>>>>>
>>>>>
>>>>> While preparing a different patch which uses the Mbox framework, I
>>>>> noticed that mbox->period might not be initialized anywhere. Also, how
>>>>> is mbox->txpoll_period to be used? It appears from the description of
>>>>> txpoll_period in mbox_controller.h that you'd want to use that value
>>>>> in the mod_timer above, or equate the two somewhere in the controller
>>>>> registration or eliminate one of the two. FWIW I also looked at your
>>>>> code in [1].
>>>>>
>>>>
>>>> IIUC the controller needs to set the txpoll_period if it sets
>>>> txdone_poll, may be a sanity check for !0 would be good.
>>>>
>>>
>>> Ah, sorry I confused mbox->period to txpoll_period.
>>> You are right mbox->period is not set, the header claims it to be
>>> private, and hence I assume it needs to be handled only in core mailbox
>>> library. Not sure if we need both mbox->period and txpoll_period though.
>>
>> Right. I dont see the need for having both either. Unless the Mailbox
>> maintainer wants to fix this in some other way, I can send a patch for
>> replacing mbox->period with mbox->txpoll_period along with my PCC
>> work.
>>
> Yeah, probably we should just get rid of mbox_controller.period  I
> have updated the same in for-next.

Looks like linux-next already has the older version[1]. Your for-next
branch seems to have the fix squashed into the previous commit.
Wouldnt you need to send this as a separate patch? Or ask for the
patch to be reverted in linux-next and then pull again from your
branch.

Thanks,
Ashwin

[1] - http://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/tree/drivers/mailbox/mailbox.c
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