[U-Boot] [PATCH v2 7/8] FAT: Simplify get_contents

[Benoît Thébaudeau]

On Wednesday, September 5, 2012 12:10:41 AM, Tom Rini wrote:
> On 09/04/2012 03:07 PM, Benoît Thébaudeau wrote:
> > On Tuesday, September 4, 2012 10:50:34 PM, Tom Rini wrote:
> >> On Sun, Sep 02, 2012 at 05:25:20PM +0200, Wolfgang Denk wrote:
> >>> Dear Beno??t Th??baudeau,
> >>>
> >>> In message
> >>> <1663419836.332713.1342790497668.JavaMail.root at advansee.com> you
> >>> wrote:
> >>>> One call to get_cluster can be factorized with another, so avoid
> >>>> duplicatin> g
> >>>> code.
> >>>>
> >>>> Signed-off-by: Beno??t Th??baudeau
> >>>> <benoit.thebaudeau at advansee.com>
> >>>> Cc: Wolfgang Denk <wd at denx.de>
> >>>> ---
> >>>> Changes for v2:
> >>>>  - Patch renumbering because of the new v2 1/8.
> >>>>  - Possible code style changes due to the new v2 1/8.
> >>>>
> >>>>  .../fs/fat/fat.c                                   |   14
> >>>>  +-------------
> >>>>  1 file changed, 1 insertion(+), 13 deletions(-)
> >>>
> >>> Applied, thanks.
> >>
> >> OK, this change is NOT equivalent code.  My platforms now hang
> >> thusly
> >> (with DEBUG set):
> >> reading u-boot.img
> >> VFAT Support enabled
> >> FAT16, fat_sect: 4, fatlength: 144
> >> Rootdir begins at cluster: 0, sector: 292, offset: 24800
> >> Data begins at: 316
> >> Sector size: 512, cluster size: 4
> >> FAT read sect=292, clust_size=4, DIRENTSPERBLOCK=16
> >> Rootvfatname: |u-boot.ais|
> >> RootMismatch: |u-boot.ais|u-boot.ais|
> >> RootMismatch: |u-boot.ais||
> >> RootMismatch: |mlo||
> >> Rootvfatname: |u-boot.img|
> >> RootName: u-boot.img, start: 0xc2, size:  0x337d0
> >> Filesize: 210896 bytes
> >> 64 bytes
> >> gc - clustnum: 194, startsect: 1092
> >> Size: 210896, got: 64
> >>
> >> This is all fine in full U-Boot.
> > 
> > OK. I'm looking into it.
> > 
> > Can you give more details, like the type of storage (usb, mmc,
> > etc.)? Do you
> > have a command line and a disk image that could be used to
> > duplicate the issue?
> 
> It's an SD card.  If you have any "OMAP" platform (beagleboard,
> beaglebone, pandaboard) or am35x/am37x or similar platforms SPL
> should
> hang like that.

Unfortunately, I don't have these platforms.

>  72MB partition (or so) on either a 2 or 4GB card.
> Getting all the way up into U-Boot clears the problem away until
> power
> cycle.  That last part makes me worried...

What do you mean by "Getting all the way up into U-Boot"? Is it that your SPL
can be aborted and give a command prompt?

The only difference that this specific patch (7/8) introduces in your use case
(i.e. a request to read the first 64 bytes of a file of 210896 bytes) is that it
removes a spurious call to get_cluster() with a size of 0, which should be
transparent.

Can you confirm that your tests bisect to this patch and not to another one in
this series?

Can you try to apply locally 5/8 and 8/8 to see if it makes a difference, just
in case there would be some dependencies?

Is it OK to send e-mails with attachments on the ML? If so, I can post the full
fat.c that I currently use so that you can test with it. I have used it for a
couple of years without any issue.

Also, why do you read only 64 bytes from this file? According to your debug
trace, this read was successful, and then no error is shown. So, if it hangs, it
might be that the read data is corrupted, or that the image is not fully read
because of this 64-byte limit.

Best regards,
Benoît