Date: Sun, 22 Mar 2015 20:41:50 -0700 From: Tim Kientzle <tim@kientzle.com> To: freebsd-arm <freebsd-arm@freebsd.org> Cc: Hellmuth Michaelis <hm@hellmuth-michaelis.de> Subject: Re: beaglebone boot from eMMC Message-ID: <756CA573-DBF6-4847-8D13-5D2586B2A1C8@kientzle.com> In-Reply-To: <B9883BEF-FD80-4421-8D10-6A5193EC8131@kientzle.com> References: <3DF08C65-20E3-4524-B0E1-C5C096AA0FE8@hellmuth-michaelis.de> <B9883BEF-FD80-4421-8D10-6A5193EC8131@kientzle.com>
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For those following along at home: There seem to be at least three problems preventing eMMC booting on = BeagleBone Black right now. (For reference, I=E2=80=99m working with = up-to-date -CURRENT and the Crochet copy-to-emmc.sh script. I started = with a Crochet-built SD image from an amd64 system, then did a native = build to upgrade before experimenting with ways to format and populate = the eMMC image.) 1) FAT partition format. newfs_msdos trims the FAT format to an even = number of tracks, but the AM335x ROM insists that a valid FAT format = exactly fill the partition. Following a suggestion from Luiz Otavio O Souza, I=E2=80=99ve adjusted = the copy-to-emmc.sh script in Crochet with parameters that seem to = result in the FAT partition being aligned on a track boundary. Real Solution: Fix newfs_msdos to not trim or at least provide an = option. Guy Yur has filed = https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D183234 = <https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D183234>; with some ideas on this. 2) Ubldr not finding boot device. I=E2=80=99m running into this now. = This could be related to U-Boot (ubldr uses U-Boot to identify and = access drives), but U-Boot seems to have no trouble reading the eMMC (in = particular, it loads ubldr successfully), so I=E2=80=99m skeptical = that=E2=80=99s the problem. 3) Geom rejects BSD labels with more than 255 sectors per track. The = BBB eMMC reads as 1024 sectors per track. Would it make sense to = remove the check in g_part_bsd.c that rejects labels with more than 255 = sectors? Related: Could someone please add GEOM_LABEL to the BEAGLEBONE kernel? = The eMMC shows up as either mmcsd0 or mmcsd1 depending on how you boot, = so label-based mounting is pretty essential.
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