Linux on ARM based TI OMAP SoCs
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From: Peter Ujfalusi <peter.ujfalusi@nokia.com>
To: David Cohen <david.cohen@nokia.com>
Cc: Tony Lindgren <tony@atomide.com>,
	"linux-omap@vger.kernel.org" <linux-omap@vger.kernel.org>,
	Jarkko Nikula <jhnikula@gmail.com>,
	Liam Girdwood <lrg@slimlogic.co.uk>, Nishanth Menon <nm@ti.com>
Subject: Re: [PATCH v2 2/2] OMAP3: DMA: Errata: sDMA FIFO draining does not finish
Date: Fri, 1 Oct 2010 15:16:53 +0300	[thread overview]
Message-ID: <201010011516.54190.peter.ujfalusi@nokia.com> (raw)
In-Reply-To: <20101001115037.GA12614@esdhcp036161.research.nokia.com>

On Friday 01 October 2010 14:50:37 David Cohen wrote:
> 
> > +		l = sys_cf = dma_read(OCP_SYSCONFIG);
> 
> Shouldn't it be avoided?

I'm restoring the OCP_SYSCONFIG register later on, and reusing 'l' here to avoid 
confusing expression when moving the sDMA to NoStandby.
I could as well introduce other variable for this...

> 
> Regards,
> 
> David
> 
> > +		l &= ~DMA_SYSCONFIG_MIDLEMODE_MASK;
> > +		l |= DMA_SYSCONFIG_MIDLEMODE(DMA_IDLEMODE_NO_IDLE);
> > +		dma_write(l , OCP_SYSCONFIG);

I could have:
	dma_write((sys_fc & (~DMA_SYSCONFIG_MIDLEMODE_MASK)) |
			 DMA_SYSCONFIG_MIDLEMODE(DMA_IDLEMODE_NO_IDLE), OCP_SYSCONFIG);

Than I do not need the re-read the CCR, but it looks a bit messy.

> > +
> > +		l = dma_read(CCR(lch));
> > +		l &= ~OMAP_DMA_CCR_EN;
> > +		dma_write(l, CCR(lch));
> > +

...

> > +		/* Restore OCP_SYSCONFIG */
> > +		dma_write(sys_cf, OCP_SYSCONFIG);

-- 
Péter
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  reply	other threads:[~2010-10-01 12:16 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-01 11:04 [PATCH v2 0/2] OMAP2/3: DMA: FIFO drain errata fixes Peter Ujfalusi
2010-10-01 11:04 ` [PATCH v2 1/2] omap: dma: Fix buffering disable bit setting for omap24xx Peter Ujfalusi
2010-10-01 11:04 ` [PATCH v2 2/2] OMAP3: DMA: Errata: sDMA FIFO draining does not finish Peter Ujfalusi
2010-10-01 11:50   ` David Cohen
2010-10-01 12:16     ` Peter Ujfalusi [this message]
2010-10-01 12:17       ` David Cohen
2010-10-01 12:43         ` Peter Ujfalusi
2010-10-01 12:24       ` Felipe Balbi
2010-10-01 12:30         ` Peter Ujfalusi

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