linux-kernel - Re: [patch 4/7] SDHCI: Add quirk for controller with no end-of-busy IRQ

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Message-ID: <20081115235849.GC9161@fluff.org.uk>
Date:	Sat, 15 Nov 2008 23:58:49 +0000
From:	Ben Dooks <ben-linux@...ff.org>
To:	Pierre Ossman <drzeus-mmc@...eus.cx>
Cc:	Ben Dooks <ben-linux@...ff.org>, linux-kernel@...r.kernel.org,
	sdhci-devel@...t.drzeus.cx
Subject: Re: [patch 4/7] SDHCI: Add quirk for controller with no
	end-of-busy IRQ

On Fri, Nov 14, 2008 at 10:41:14PM +0100, Pierre Ossman wrote:
> On Mon, 03 Nov 2008 20:09:48 +0000
> Ben Dooks <ben-linux@...ff.org> wrote:
> 
> > The Samsung SDHCI controller block seems to fail to generate an
> > INT_DATA_END after the transfer has completed and the bus busy
> > state finished. 
> > 
> > Changes in e809517f6fa5803a5a1cd56026f0e2190fc13d5c to use the
> > new busy method are the cause of the behaviour change.
> > 
> > Signed-off-by: Ben Dooks <ben-linux@...ff.org>
> > 
> > Index: linux.git/drivers/mmc/host/sdhci.c
> > ===================================================================
> > --- linux.git.orig/drivers/mmc/host/sdhci.c	2008-11-03 10:01:03.000000000 +0000
> > +++ linux.git/drivers/mmc/host/sdhci.c	2008-11-03 12:20:40.000000000 +0000
> > @@ -1291,11 +1291,24 @@ static void sdhci_cmd_irq(struct sdhci_h
> >  	 *       controllers.
> >  	 */
> >  	if (host->cmd->flags & MMC_RSP_BUSY) {
> > +		u32 present;
> > +
> >  		if (host->cmd->data)
> >  			DBG("Cannot wait for busy signal when also "
> >  				"doing a data transfer");
> > -		else
> > +		else if (!(host->quirks & SDHCI_QUIRK_NO_TCIRQ_ON_NOT_BUSY))
> >  			return;
> 
> Not the clearest naming I've ever seen. :)
> How about NO_BUSY_IRQ?

ok, will change.
 
> > +
> > +		/* The Samsung SDHCI does not seem to provide an INT_DATA_END
> > +		 * when the system goes non-busy, so check the state of the
> > +		 * transfer by reading SDHCI_PRESENT_STATE to see if the
> > +		 * controller is ready
> > +		 */
> 
> There is already a note about this being a problem earlier up, so I
> don't think we need another.

right.
 
> > +
> > +		present = readl(host->ioaddr + SDHCI_PRESENT_STATE);
> > +		DBG("busy? present %08x, intstat %08x\n", present, intmask);
> > +
> 
> And what does this add really? Controllers not being able to wait for
> the busy state to end is so common that we can just ignore the problem
> here.
> 

that was debug.

> > +#define  SDHCI_DATA_BIT(x)	(1 << ((x) + 20))
> 
> This was not supposed to be included I suppose :)

was with teh debug.

-- 
Ben (ben@...ff.org, http://www.fluff.org/)

  'a smiley only costs 4 bytes'
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