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Date:      Thu, 22 Jan 2009 15:57:41 -0700 (MST)
From:      "M. Warner Losh" <imp@bsdimp.com>
To:        ticso@cicely.de, ticso@cicely7.cicely.de
Cc:        mav@FreeBSD.org, freebsd-arm@FreeBSD.org
Subject:   Re: Mount root from SD card?
Message-ID:  <20090122.155741.-470325804.imp@bsdimp.com>
In-Reply-To: <20090122180518.GK50103@cicely7.cicely.de>
References:  <20090122151340.GE50103@cicely7.cicely.de> <4978B4A6.8060408@FreeBSD.org> <20090122180518.GK50103@cicely7.cicely.de>

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In message: <20090122180518.GK50103@cicely7.cicely.de>
            Bernd Walter <ticso@cicely7.cicely.de> writes:
: On Thu, Jan 22, 2009 at 08:02:14PM +0200, Alexander Motin wrote:
: > Bernd Walter wrote:
: > >As another point:
: > >Is it possible to support SHDC with mci some day, or is there a special
: > >hardware requirement for SDHC?
: > 
: > SDHC (SD High Capacity) has just a different data addressing scheme (in 
: > 512bytes blocks instead of bytes). There is no special hardware 
: > requirements, only minor initialization differences. With present 
: > mmc/mmcsd modules SDHC should work fine on any controller.
: 
: Good news - thank you for clearification.

Now all we need to do is to enhance the boot blocks to be able to boot
off the SDHC cards :)

BTW, I found and fixed the bug (at least I think so).  We were
assuming that all transfers were 512 bytes long.  The newly used 16
and 64 byte transfers broke that assumption, which is why things broke
after Alexander's latest commits.  There's still a small chance that
there's something borked in the byte swapping code, but I kinda doubt
it since I was able to mount root.

svn commit r187603 is the fix.

Warner



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