Re: [microblaze-uclinux] FAT FS troubles

[John Williams <jwilliams@xxxxxxxxxxxxxx>]

Hi Rudi,

Rudolf Usselmann wrote:

> I am trying to bring up a block device driver that talks to
> our SD/MMC Host IP Core. First I boot Linux from this card,
> than I am trying to mount the Card under linux.
> 
> Everything seems to work just fine except the mounting part.
> 
>>From my analysis, it looks like the card is properly read,
> it's the FAT FS part of ucLinux that is barking at my card(s).

If you enable the dd and hexdump (hd) user applications in your uclinux 
build, can you do something like this:

dd if=/dev/mmc0 bs=512 count=2 | hd

and compare the output with a hexdump of the same card on a linux PC? 
Just to confirm that the driver is in fact reading the sectors correctly?

If you're lucky it might just be an endian issue or something similarly 
easily fixed.

Another thing to test is try making an MSDOS filesys on a ramdisk under 
uClinux, and make sure you can mount it etc.  You could do this by 
running mkfs.fat on your host, to just make an empty filesystem image, 
transfer that image to the uclinux board, put it somewhere writeable 
(/tmp?), then mount it with the -o loop option.  Make sure you compile 
in support for loop devices in the kernel and mount application.

> It seems that NONE of the cards (we have about two dozen of
> cards for testing here) have a proper "boot sector". So as I
> try to mount the card, I get all kind of complains from the
> FAT FS.

Can you post some representative samples of these error messages?

Thanks,

John

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