Date: Tue, 20 Jan 2009 20:09:30 +0200 From: Alexander Motin <mav@FreeBSD.org> To: Krassimir Slavchev <krassi@bulinfo.net> Cc: freebsd-arm@freebsd.org Subject: Re: Mount root from SD card? Message-ID: <4976135A.3070109@FreeBSD.org> In-Reply-To: <49760E8E.1000609@FreeBSD.org> References: <1232392983.00063248.1232380802@10.7.7.3> <1232400185.00063286.1232389201@10.7.7.3> <1232450582.00063538.1232438401@10.7.7.3> <49760E8E.1000609@FreeBSD.org>
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Alexander Motin wrote: > Krassimir Slavchev wrote: >> -----BEGIN PGP SIGNED MESSAGE----- >> Hash: SHA1 >> >> M. Warner Losh wrote: >> ... >>> mmcsd0: 1983MB <SD Memory Card> at mmc0 30MHz/1bit >>> Trying to mount root from ufs:/dev/mmcsd0s1 >>> >>> Manual root filesystem specification: >>> <fstype>:<device> Mount <device> using filesystem <fstype> >>> eg. ufs:/dev/da0a >>> ? List valid disk boot devices >>> <empty line> Abort manual input >>> >>> mountroot> ? >>> >>> List of GEOM managed disk devices: >>> mmcsd0 >>> >>>> Looks like that should be working. >>>> mav@ has done a lot of hacking on the mmc code... >>>> Do you have 1 wire or 4 wires for your mmc bus on your board? >> >> On the board all 4 bus wires are connected (MCD A0-A3) but I've never >> seen working 4-bit mode on AT91RM9200 (See PR128987 too). > > I have just committed MMCBR_IVAR_CAPS implementation into CURRENT. > Without having it implemented, results can be unpredictable. For > example, mmc layer could enable high-speed timings to reach 30MHz, but > this mode is not implemented for this controller. Booting with verbose > messages enabled could give a bit more information. > > What's about 4-bit mode, I see some sc->wire4 variable checked by the > driver, which is never initialized. I don't very understand how this > thing expected to work. As I can see from specification, if sc->wire4 is set to 0 by default, bus will not ever switched into 4bit mode. Try to just comment out " && sc->wire4" part of at91_mci.c. If this variable expected to report real bus width, then it probably should be done in different way, by reporting correct host capabilities. > PS: For MMC cards bus width testing routine implemented. May be we could > do something alike for SD cards. It is not part of SD specification, but > may be we could just issue some other command, transferring data, to > check effective bus width. -- Alexander Motin
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