[U-Boot] FAT filesystem support on SPI flash

[Vasili Galka]

Dear Jagan,

I'm not sure I fully understand your question.
SPI flash is just a medium that has sectors/pages/blocks (call it
however you want). You are free to store data with any structure you
like on it. So if you like - you can store FAT file-system on it.
That's true that maybe storing a FAT file-system that has frequent
write operations on SPI flash is not a good idea, both because of
speed and because of flash wear. But that is an entirely different
question. There are still many cases when the data does not change
frequently and FAT on SPI flash can be useful.

Best,
Vasili

On Sun, Feb 23, 2014 at 7:49 PM, Jagan Teki <jagannadh.teki at gmail.com> wrote:
> On Sun, Feb 23, 2014 at 7:07 PM, Vasili Galka <vasili at visionmap.com> wrote:
>> Hi,
>>
>> On our system, we are interested in keeping all files, including the OS image and U-Boot second stage on FAT filesystem residing on a SPI flash.
>
> I'm not a file-system expert, but I've a basic question like how
> does/well a SPI flash(mtd) device have
> FAT support on it. Generally flash file-systems were categories to do
> the job right?
>
>>
>> I have not found existing U-Boot support for such functionality. Have I missed it?
>>
>> In any case, I'm willing to implement this, do you see it reasonable incorporating such code into U-Boot? (if it passes review of course)
>>
>> I note about design: As our chip (TI's AM335x) does not support direct boot from FAT stored on SPI, I plan reserving section at the beginning of SPI flash for the first stage boot loader and having the filesystem after it.
>
> thanks!
> --
> Jagan.