linux-kernel - Re: [PATCH] dma: dw: Add suspend and resume handling for PCI mode DW

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Message-ID: <20131218154955.GF16227@intel.com>
Date:	Wed, 18 Dec 2013 21:19:55 +0530
From:	Vinod Koul <vinod.koul@...el.com>
To:	"Chew, Chiau Ee" <chiau.ee.chew@...el.com>
Cc:	"Shevchenko, Andriy" <andriy.shevchenko@...el.com>,
	Viresh Kumar <viresh.linux@...il.com>,
	Andy Shevchenko <andriy.shevchenko@...ux.jf.intel.com>,
	"Williams, Dan J" <dan.j.williams@...el.com>,
	"dmaengine@...r.kernel.org" <dmaengine@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] dma: dw: Add suspend and resume handling for PCI mode
 DW_DMAC.

On Mon, Dec 16, 2013 at 01:51:47PM +0530, Chew, Chiau Ee wrote:
> Vinod,
Please do *NOT* top post

Please fix your MUA to wrap lines with 80chars. I have fix below to make it
readble...

> As mentioned by Andy, we are using *_noirq  verion of suspend/resume PM
> callback whereby the callbacks would be executed after IRQ handlers have been
> disabled. If using SET_SYSTEM_SLEEP_PM_OPS, it would be the normal
> suspend/resume PM callback. Looking at the Desginware DMAC platform code
> (drivers/dma/dw/platform.c), it is using the *_noirq suspend/resume PM
> callback. Is it advisable to use the normal suspend/resume PM callback instead
> of *_noirq suspend/PM callback? 

i dont see a reason why we need the noirq versions

--
~Vinod

> 
> Thanks,
> Chiau Ee
> 
> -----Original Message-----
> From: Shevchenko, Andriy 
> Sent: Tuesday, December 10, 2013 7:57 PM
> To: Koul, Vinod
> Cc: Chew, Chiau Ee; Viresh Kumar; Andy Shevchenko; Williams, Dan J; dmaengine@...r.kernel.org; linux-kernel@...r.kernel.org
> Subject: Re: [PATCH] dma: dw: Add suspend and resume handling for PCI mode DW_DMAC.
> 
> On Tue, 2013-12-10 at 15:40 +0530, Vinod Koul wrote:
> > On Tue, Dec 10, 2013 at 10:06:13PM +0800, Chew Chiau Ee wrote:
> > > From: Chew, Chiau Ee <chiau.ee.chew@...el.com>
> > > 
> > > This is to disable/enable DW_DMAC hw during suspend/resume.
> > > 
> > > Signed-off-by: Chew, Chiau Ee <chiau.ee.chew@...el.com>
> > > Acked-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> > > ---
> > >  drivers/dma/dw/pci.c |   33 +++++++++++++++++++++++++++++++++
> > >  1 files changed, 33 insertions(+), 0 deletions(-)
> > > 
> > > diff --git a/drivers/dma/dw/pci.c b/drivers/dma/dw/pci.c index 
> > > e89fc24..97bc3a2 100644
> > > --- a/drivers/dma/dw/pci.c
> > > +++ b/drivers/dma/dw/pci.c
> > > @@ -75,6 +75,36 @@ static void dw_pci_remove(struct pci_dev *pdev)
> > >  		dev_warn(&pdev->dev, "can't remove device properly: %d\n", ret);  
> > > }
> > >  
> > > +#ifdef CONFIG_PM_SLEEP
> > > +
> > > +static int dw_pci_suspend_noirq(struct device *dev) {
> > > +	struct pci_dev *pci = to_pci_dev(dev);
> > > +	struct dw_dma_chip *chip = pci_get_drvdata(pci);
> > > +
> > > +	return dw_dma_suspend(chip);
> > > +};
> > > +
> > > +static int dw_pci_resume_noirq(struct device *dev) {
> > > +	struct pci_dev *pci = to_pci_dev(dev);
> > > +	struct dw_dma_chip *chip = pci_get_drvdata(pci);
> > > +
> > > +	return dw_dma_resume(chip);
> > > +};
> > > +
> > > +#else /* !CONFIG_PM_SLEEP */
> > > +
> > > +#define dw_pci_suspend_noirq	NULL
> > > +#define dw_pci_resume_noirq	NULL
> > > +
> > > +#endif /* !CONFIG_PM_SLEEP */
> > How about SET_SYSTEM_SLEEP_PM_OPS instead?
> 
> So, we are using *_noirq versions of the functions here. What happened when we switch to normal ones? Any side effects?
> 
> > 
> > --
> > ~Vinod
> > > +
> > > +static const struct dev_pm_ops dw_pci_dev_pm_ops = {
> > > +	.suspend_noirq = dw_pci_suspend_noirq,
> > > +	.resume_noirq = dw_pci_resume_noirq, };
> > > +
> > >  static DEFINE_PCI_DEVICE_TABLE(dw_pci_id_table) = {
> > >  	/* Medfield */
> > >  	{ PCI_VDEVICE(INTEL, 0x0827), (kernel_ulong_t)&dw_pci_pdata }, @@ 
> > > -92,6 +122,9 @@ static struct pci_driver dw_pci_driver = {
> > >  	.id_table	= dw_pci_id_table,
> > >  	.probe		= dw_pci_probe,
> > >  	.remove		= dw_pci_remove,
> > > +	.driver	= {
> > > +		.pm	= &dw_pci_dev_pm_ops,
> > > +	},
> > >  };
> > >  
> > >  module_pci_driver(dw_pci_driver);
> > > --
> > > 1.7.4.4
> > > 
> > 
> 
> --
> Andy Shevchenko <andriy.shevchenko@...el.com> Intel Finland Oy

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