Date: Fri, 23 Jan 2009 00:57:12 +0100 From: Bernd Walter <ticso@cicely7.cicely.de> To: "M. Warner Losh" <imp@bsdimp.com> Cc: freebsd-arm@FreeBSD.org, mav@FreeBSD.org, ticso@cicely7.cicely.de, ticso@cicely.de Subject: Re: Mount root from SD card? Message-ID: <20090122235712.GO50103@cicely7.cicely.de> In-Reply-To: <20090122.162633.1849591410.imp@bsdimp.com> References: <20090122180518.GK50103@cicely7.cicely.de> <20090122.155741.-470325804.imp@bsdimp.com> <20090122230647.GN50103@cicely7.cicely.de> <20090122.162633.1849591410.imp@bsdimp.com>
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On Thu, Jan 22, 2009 at 04:26:33PM -0700, M. Warner Losh wrote: > In message: <20090122230647.GN50103@cicely7.cicely.de> > Bernd Walter <ticso@cicely7.cicely.de> writes: > : On Thu, Jan 22, 2009 at 03:57:41PM -0700, M. Warner Losh wrote: > : > 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 :) > : > : Yes, but since you wrote code to store the kernel inside SPI-flash > : there is a useable workaround available ;-) > : Full loader support would be more interesting than SDHC in boot code > : anyway. > > Raj@ did some interesting work in this area for the marvel port... I already noticed his work with great pleasure. > : > 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. > : > : Great! > > Well, it doesn't work in 4-bit bus mode. Of course, I'm not sure it > ever worked in 4-bit bus mode... It never worked - I tried it a while back and had interesting results, but it wasn't stable, which I asumed to be my bad knowledge on how this should be implemented correctly. Thanks to mav@ we have other controllers working and can test the sdmmc part unrelated from mci. Nevertheless: multiblock is the real speed issue. My speed tests were very impressive, but because of mci problems data were corrupted of course. -- B.Walter <bernd@bwct.de> http://www.bwct.de Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.
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