Hi eric,
Eric Nelson wrote:
Hello all,
I've recently been looking into a problem loading files from a FAT32 filesystem and (re)discovered that there are issues with this code.
Some of the symptoms are related to problems discussed in a thread back in April titled "USB SUPPORT & get_vfatname".
http://lists.denx.de/pipermail/u-boot/2008-April/033117.html
I ran into the issue(s) on an SD(MMC) card when I noticed a failure to load a certain file from the card.
I've been able to narrow down a set of problems in fs/fat.c. I'm not sure when I'll have the time to generate a proper patch, but wanted to at least write some notes on the nature of the problem to save others some grief.
The first problem I encountered was that the main loop in fs/fat.c/do_fat_read was built for fixed-size root directories. The Microsoft document "FAT: General Overview of On-Disk Format" says this on page 22: "For FAT32, the root directory can be of variable size and is a cluster chain, just like any other ..."
When running the command:
fatls mmc 0
I try to investigate but I don't have spare time to fix. I send to the list an linux-user space program that use the u-boot routine to read on the image. You can use that to track down the problem. Regards Michael