linux-kernel - RE: [PATCH v9 1/1] irqchip: imx-gpcv2: IMX GPCv2 driver for wakeup sources

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Message-ID: <CY1PR0301MB08439BB31108FD3DDC234EDA83610@CY1PR0301MB0843.namprd03.prod.outlook.com>
Date:	Tue, 25 Aug 2015 20:43:36 +0000
From:	Shenwei Wang <Shenwei.Wang@...escale.com>
To:	Thomas Gleixner <tglx@...utronix.de>
CC:	Sudeep Holla <sudeep.holla@....com>,
	"shawn.guo@...aro.org" <shawn.guo@...aro.org>,
	"jason@...edaemon.net" <jason@...edaemon.net>,
	"Huang Anson" <Anson.Huang@...escale.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>
Subject: RE: [PATCH v9 1/1] irqchip: imx-gpcv2: IMX GPCv2 driver for wakeup
 sources



> -----Original Message-----
> From: Thomas Gleixner [mailto:tglx@...utronix.de]
> Sent: 2015年8月25日 15:16
> To: Wang Shenwei-B38339
> Cc: Sudeep Holla; shawn.guo@...aro.org; jason@...edaemon.net; Huang
> Yongcai-B20788; linux-kernel@...r.kernel.org;
> linux-arm-kernel@...ts.infradead.org
> Subject: RE: [PATCH v9 1/1] irqchip: imx-gpcv2: IMX GPCv2 driver for wakeup
> sources
> 
> On Tue, 25 Aug 2015, Shenwei Wang wrote:
> > > From: Thomas Gleixner [mailto:tglx@...utronix.de]
> > > > IRQCHIP_MASK_ON_SUSPEND flag is for the hardware that has no
> > > > wakeup source capability.  This GPCv2 block is designed to manage
> > > > the wakeup source, so the flag does not make any sense.
> > >
> > > You have no seperate wakeup source mechanism. All you do is to mask
> > > all non wakeup sources and keep the wakeup sources unmask.
> > >
> > > That's what happens in gpcv2_wakeup_source_save()
> > >
> > >        writel_relaxed(cd->wakeup_sources[i], reg);
> > >
> > > So it's the same as letting the core mask all non wakeup sources and
> > > leave the wakeup sources unmask.
> >
> > Does it mean an unexpected interrupt may activate the system, and the
> > core will let the system go into suspend again if the core determines
> > it not a wakeup source? The current design is to ignore all the
> > unexpected interrupts in the hardware level. Only the presetting
> > wakeup sources can activate the platform. Here power consumption is
> > more important.
> 
> Did you actually read, what I wrote?
> 
> The core does in case of MASK_ON_SUSPEND
> 
>     for_each_irq() {
> 	if (!irq->wakeupsource)
> 	   mask(irq)
>     }
> 
> That's identical to what you are doing. You just do it differently by saving the
> active wakeup sources in your own data structure and then write that info to the
> mask register, which leaves only the wakeup sources unmasked.

Sorry. I just took a study on the two flags: MASK_ON_SUSPEND and IRQCHIP_SKIP_SET_WAKE.
MASK_ON_SUSPEND flag does simply the implementation. 
IRQCHIP_SKIP_SET_WAKE flag can't be used here because the wakeup sources are required for power management.
I will send out a subsequent patch to simply the implementation by using this idea.

Thank you Sudeep for the insightful review!

Thanks,
Shenwei



> Thanks,
> 
> 	tglx