fat: handle Windows formatted partition (thru USB Mass Storage)

[AKASHI Takahiro]

On Tue, Jan 14, 2020 at 02:43:43PM +0200, Andy Shevchenko wrote:
> On Tue, Jan 14, 2020 at 10:23 AM Andy Shevchenko
> <andy.shevchenko at gmail.com> wrote:
> > On Tue, Jan 14, 2020 at 10:21 AM Andy Shevchenko
> > <andy.shevchenko at gmail.com> wrote:
> > > On Tue, Jan 14, 2020 at 1:14 AM Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
> > > > On 1/13/20 10:52 PM, Andy Shevchenko wrote:
> >
> > ...
> >
> > > > This image loads fine on current U-Boot, see below.
> > >
> > > Of course it does *in the test case you have done*.
> > > I'm describing different one. The provided image must be a *partition*
> > > on the real disk.
> > >
> > > So, before use it the preparatory steps must be made.
> > >
> > > Something like
> > >
> > > % dd if=/dev/zero of=image-file bs=1M count=1000
> > > % fdisk image-file
> > >  ...create a partition table, where one partition has a (similar) size
> > > of the image I provided
> > > % mount -o loop,offset=... image-file /mnt # use *partition* as a disk!
> > > % dd --sparse if=mmc-fat-part of=/mnt
> > > % umount /mnt
> > >
> > > And use image-file instead.
> >
> > Should I prepare it for you or you can do it yourself?
> 
> It's there under name image-file.gz

===8<===
$ hd image-file
00000000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
000001b0  00 00 00 00 00 00 00 00  59 02 8c 89 00 00 00 20  |........Y...... |
000001c0  21 00 0c 08 27 62 00 08  00 00 01 00 18 00 00 00  |!...'b..........|
000001d0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
(snip)
00100000  eb 3c 90 6d 6b 64 6f 73  66 73 00 00 02 20 01 00  |.<.mkdosfs... ..|
00100010  02 00 02 00 00 f8 c0 00  10 00 04 00 00 00 00 00  |................|
00100020  00 00 18 00 80 00 29 ea  36 23 57 20 20 20 20 20  |......).6#W     |
00100030  20 20 20 20 20 20 46 41  54 31 36 20 20 20 0e 1f  |      FAT16   ..|
(snip)
001001d0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
001001f0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 55 aa  |..............U.|
00100200  f8 ff ff ff 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00100210  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
00110000  eb 58 90 4d 53 44 4f 53  35 2e 30 00 02 08 1a 14  |.X.MSDOS5.0.....|
00110010  02 00 00 00 00 f8 00 00  3f 00 ff 00 80 00 00 00  |........?.......|
00110020  00 e8 17 00 f3 05 00 00  00 00 00 00 02 00 00 00  |................|
00110030  01 00 06 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00110040  80 00 29 f8 a9 74 d0 4e  4f 20 4e 41 4d 45 20 20  |..)..t.NO NAME  |
00110050  20 20 46 41 54 33 32 20  20 20 33 c9 8e d1 bc f4  |  FAT32   3.....|
(snip)
===>8===

[0x100000-0x100200) looks to be PBR.
[0x110000-0x110050) looks to be MBR.
But I don't know what is [0x0-0x100000).
Obviously U-Boot's fat code cannot handle it.

Thanks,
-Takahiro Akashi


> Commit messages have the commands I performed to get this image cooked.
> 
> -- 
> With Best Regards,
> Andy Shevchenko