at91: Status of NAND flash access
Josh Wu
josh.wu at atmel.com
Tue Dec 4 05:54:25 EST 2012
Hi, Bryan
On 12/3/2012 10:39 PM, Bryan Evenson wrote:
> I have a kernel build of 3.7-rc5 that is built for the AT91SAM9G25. The kernel has issues when it tries to read the filesystem from NAND flash. If I change to an NFS setup then the filesystem loads.
According to your question, it is not very clear to me, so could you
give more detail then I can help.
What type (ubi, jffs2, or others) of your filesystem is used? How do you
flush the file system into the nand flash, by SAM-BA, or U-Boot? With or
without pmecc?
And what ecc type (pmecc, soft, none) do you enabled in the kernel?
> I've seen some patches on this list lately related to AT91 NAND flash (specifically this thread: http://lists.infradead.org/pipermail/linux-arm-kernel/2012-November/133748.html) and I believe my problems may be related to this issue. But, I'm having trouble following the thread to find the current status.
>
> Can anyone tell me what the status is on NAND flash access for the AT91 series with the 3.7-rc5 kernel? If this version has a known bug, is there a different suggested version I use that fixes the issue?
In 3.7-rc5, I think the atmel nand driver should work well with
AT91SAM9G25EK board even without the patch you mentioned in above URL.
Just for PMECC, you need add following code in
arch/arm/boot/dts/at91sam9x5cm.dtsi:
- nand-ecc-mode = "soft";
+ nand-ecc-mode = "hw";
+ atmel,has-pmecc; /* Enable PMECC */
+ atmel,pmecc-cap = <2>; /* PMECC error bits*/
+ atmel,pmecc-sector-size = <512>; /* sector
size for PMECC, it is not page size */
Also you can check the readme file in:
Documentation/devicetree/bindings/mtd/atmel-nand.txt
Best Regards,
Josh Wu
>
> Thanks,
> Bryan
>
>
>
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