linux-kernel - Re: [PATCH] OMAP: HSMMC: Do not enable buffer ready interrupt if using DMA

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Message-ID: <20090430185844.GG12986@atomide.com>
Date:	Thu, 30 Apr 2009 11:58:45 -0700
From:	Tony Lindgren <tony@...mide.com>
To:	Pierre Ossman <pierre@...man.eu>
Cc:	Jarkko Lavinen <jarkko.lavinen@...ia.com>,
	"Gadiyar, Anand" <gadiyar@...com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>,
	Adrian Hunter <adrian.hunter@...ia.com>
Subject: Re: [PATCH] OMAP: HSMMC: Do not enable buffer ready interrupt if
	using DMA

* Pierre Ossman <pierre@...man.eu> [090428 12:38]:
> Jarkko? Tony?

Hmm, we haven't heard from Jarkko for a while.. Adrian, care to take
a look at this patch?

Tony
 
> On Tue, 21 Apr 2009 13:09:22 +0530
> "Gadiyar, Anand" <gadiyar@...com> wrote:
> 
> > From: Anand Gadiyar <gadiyar@...com>
> > 
> > OMAP: HSMMC: Do not enable buffer ready interrupt if using DMA
> > 
> > This considerably reduces the number of interrupts during a transfer
> > and ought to result in some power saving.
> > 
> > Signed-off-by: Anand Gadiyar <gadiyar@...com>
> > Signed-off-by: Santosh Shilimkar <santosh.shilimkar@...com>
> > Acked-by: Kishore Kadiyala <kishore.kadiyala@...com>
> > ---
> > diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
> > index e62a22a..2d83807 100644
> > --- a/drivers/mmc/host/omap_hsmmc.c
> > +++ b/drivers/mmc/host/omap_hsmmc.c
> > @@ -70,6 +70,8 @@
> >  #define DTO_MASK		0x000F0000
> >  #define DTO_SHIFT		16
> >  #define INT_EN_MASK		0x307F0033
> > +#define BWR_ENABLE		(1 << 4)
> > +#define BRR_ENABLE		(1 << 5)
> >  #define INIT_STREAM		(1 << 1)
> >  #define DP_SELECT		(1 << 21)
> >  #define DDIR			(1 << 4)
> > @@ -241,7 +243,12 @@ mmc_omap_start_command(struct mmc_omap_host *host, struct mmc_command *cmd,
> >  	 */
> >  	OMAP_HSMMC_WRITE(host->base, STAT, STAT_CLEAR);
> >  	OMAP_HSMMC_WRITE(host->base, ISE, INT_EN_MASK);
> > -	OMAP_HSMMC_WRITE(host->base, IE, INT_EN_MASK);
> > +
> > +	if (host->use_dma)
> > +		OMAP_HSMMC_WRITE(host->base, IE,
> > +				 INT_EN_MASK & ~(BRR_ENABLE | BWR_ENABLE));
> > +	else
> > +		OMAP_HSMMC_WRITE(host->base, IE, INT_EN_MASK);
> >  
> >  	host->response_busy = 0;
> >  	if (cmd->flags & MMC_RSP_PRESENT) {
> 
> 
> -- 
>      -- Pierre Ossman
> 
>   WARNING: This correspondence is being monitored by the
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