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From: Yao Yuan <yao.yuan@freescale.com>
To: Vinod Koul <vinod.koul@intel.com>
Cc: "stefan@agner.ch" <stefan@agner.ch>,
	"dan.j.williams@intel.com" <dan.j.williams@intel.com>,
	"dmaengine@vger.kernel.org" <dmaengine@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>
Subject: RE: [PATCH] dmaengine: fsl-edma: add PM suspend/resume support
Date: Fri, 17 Jul 2015 05:41:55 +0000	[thread overview]
Message-ID: <BL2PR03MB338CBF3F98AFF7E93AA78C183980@BL2PR03MB338.namprd03.prod.outlook.com> (raw)
In-Reply-To: <20150716132411.GX5086@localhost>

Hi Vinod,

eDMA sullpies the data transmission service for other IPs, so it should be suspended later and resumed earlier.
For example:
Synchronous Audio Interface (SAI), SAI use DMA to transfer the data.
When suspend:
1, SAI using suspend handlers to stop the DMA transmission.
2, DMA using suspend_late  handlers to check whether DMA chan is idle.
When resume:
1, DMA using resume_early   to enable. And then can servicing for others.
2, SAI using resume and then can use DMA to data transmission.

We must sure the order is right, so I think DMA should using early/late handlers.

Thanks.

Best Regards,
Yuan Yao

On Thursday, July 16, 2015 9:24 PM, Vinod wrote:
> On Wed, Jul 15, 2015 at 05:32:58PM +0800, Yuan Yao wrote:
> > +
> > +static const struct dev_pm_ops fsl_edma_pm_ops = {
> > +	.suspend_late   = fsl_edma_suspend_late,
> > +	.resume_early   = fsl_edma_resume_early,
> any reason why you are using early/late handlers?
> 
> --
> ~Vinod


WARNING: multiple messages have this Message-ID (diff)
From: yao.yuan@freescale.com (Yao Yuan)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] dmaengine: fsl-edma: add PM suspend/resume support
Date: Fri, 17 Jul 2015 05:41:55 +0000	[thread overview]
Message-ID: <BL2PR03MB338CBF3F98AFF7E93AA78C183980@BL2PR03MB338.namprd03.prod.outlook.com> (raw)
In-Reply-To: <20150716132411.GX5086@localhost>

Hi Vinod,

eDMA sullpies the data transmission service for other IPs, so it should be suspended later and resumed earlier.
For example:
Synchronous Audio Interface (SAI), SAI use DMA to transfer the data.
When suspend:
1, SAI using suspend handlers to stop the DMA transmission.
2, DMA using suspend_late  handlers to check whether DMA chan is idle.
When resume:
1, DMA using resume_early   to enable. And then can servicing for others.
2, SAI using resume and then can use DMA to data transmission.

We must sure the order is right, so I think DMA should using early/late handlers.

Thanks.

Best Regards,
Yuan Yao

On Thursday, July 16, 2015 9:24 PM, Vinod wrote:
> On Wed, Jul 15, 2015 at 05:32:58PM +0800, Yuan Yao wrote:
> > +
> > +static const struct dev_pm_ops fsl_edma_pm_ops = {
> > +	.suspend_late   = fsl_edma_suspend_late,
> > +	.resume_early   = fsl_edma_resume_early,
> any reason why you are using early/late handlers?
> 
> --
> ~Vinod

  reply	other threads:[~2015-07-17  5:56 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-07-15  9:32 Yuan Yao
2015-07-15  9:32 ` No subject Yuan Yao
2015-07-15  9:32 ` [PATCH] dmaengine: fsl-edma: add PM suspend/resume support Yuan Yao
2015-07-15  9:32   ` Yuan Yao
2015-07-15  9:56   ` Arnd Bergmann
2015-07-15  9:56     ` Arnd Bergmann
2015-07-15 10:29     ` Yao Yuan
2015-07-15 10:29       ` Yao Yuan
2015-07-15 14:54       ` Arnd Bergmann
2015-07-15 14:54         ` Arnd Bergmann
2015-07-16  8:01         ` Yao Yuan
2015-07-16  8:01           ` Yao Yuan
2015-07-16 13:24   ` Vinod Koul
2015-07-16 13:24     ` Vinod Koul
2015-07-17  5:41     ` Yao Yuan [this message]
2015-07-17  5:41       ` Yao Yuan

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