* Re: [PATCH] ARM: MVEBU: Netgear RN102: Use Hardware BCH ECC
2014-09-05 15:41 ` [PATCH] ARM: MVEBU: Netgear RN102: Use Hardware BCH ECC Ezequiel Garcia
@ 2014-09-05 20:49 ` Arnaud Ebalard
2014-09-06 2:18 ` Ben Peddell
0 siblings, 1 reply; 3+ messages in thread
From: Arnaud Ebalard @ 2014-09-05 20:49 UTC (permalink / raw)
To: Ezequiel Garcia
Cc: Thomas Petazzoni, devicetree, klightspeed, Jason Cooper,
linux-kernel, linux-mtd, Gregory Clement, Brian Norris,
linux-arm-kernel
Hi,
Ezequiel Garcia <ezequiel.garcia@free-electrons.com> writes:
> (Fixing Cc list: dropping devicetree guys, and adding Brian and MTD instead)
>
> On 05 Sep 04:23 PM, klightspeed@killerwolves.net wrote:
>> The bootloader on the Netgear ReadyNAS RN102 uses Hardware BCH ECC
>> (strength = 4), while the pxa3xx NAND driver by default uses
>> Hamming ECC (strength = 1).
>>
>
> Hm, I guess the device (Hynix H27U1G8F2BTR) does not support ONFI,
> and the kernel is just taking the legacy ECC. The flash specs makes no
> mention to ONFI, so probably no ONFI here.
>
>> This patch changes the ECC mode on these machines to match that
>> of the bootloader and of the stock firmware, so that for example
>> updating the kernel is possible without requiring a serial
>> connection.
>>
>> This patch depends on commit 5b3e507 (mtd: nand: pxa3xx: Use ECC
>> strength and step size devicetree binding)
>>
>> Signed-off-by: Ben Peddell <klightspeed@killerwolves.net>
>
> Looks good to me, since Arnaud reports this is the correct ECC scheme:
> http://natisbad.org/NAS2/index.html#hw-nand
>
> Acked-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
>
> Thanks for the fix,
w/o the patch, you can write data to the flash using userland tools from
mtd-utils package (flash_erase and nandwrite); data can then be read
again using userland tools (say using dd). But - as reported by Ben - if
you nandwrite an uImage from userland, here is what you indeed get from
u-boot when you try and boot that image:
root@humble:~# flash_erase /dev/mtd2 0 0
Erasing 128 Kibyte @ 5e0000 -- 100 % complete
root@humble:~# nandwrite -p /dev/mtd2 /tmp/uImage-3.16.1.rn102
Writing data to block 0 at offset 0x0
Writing data to block 1 at offset 0x20000
Writing data to block 2 at offset 0x40000
Writing data to block 3 at offset 0x60000
Writing data to block 4 at offset 0x80000
...
reboot
...
Marvell>> nand read 0x1200000 0x200000 0x600000
NAND read: device 0 offset 0x200000, size 0x600000
6291456 bytes read: OK
Marvell>> bootm 0x1200000
## Booting kernel from Legacy Image at 01200000 ...
Image Name: Linux-3.16.1.rn102
Created: 2014-08-14 13:33:46 UTC
Image Type: ARM Linux Kernel Image (uncompressed)
Data Size: 4423998 Bytes = 4.2 MB
Load Address: 00008000
Entry Point: 00008000
Verifying Checksum ... Bad Data CRC
ERROR: can't get kernel image!
Now, w/ the patch submitted by Ben, here is what you get:
With the patch applied, this indeed works has
## Booting kernel from Legacy Image at 01200000 ...
Image Name: Linux-3.16.1.rn102
Created: 2014-09-05 20:25:34 UTC
Image Type: ARM Linux Kernel Image (uncompressed)
Data Size: 4424067 Bytes = 4.2 MB
Load Address: 00008000
Entry Point: 00008000
Verifying Checksum ... OK
Loading Kernel Image ... OK
OK
Starting kernel ...
i.e. it works.
So, thanks for reporting this, Ben. I must confess I got used to update
my kernels from u-boot and did not take enough attention to that
aspect when I updated the .dts to add access to NAND after Ezequiel
wrote the NAND driver. I will take a look at RN104 and RN2120 to check
if something similar is needed for those two.
FWIW, you can add my:
Tested-by: Arnaud Ebalard <arno@natisbad.org>
Additionally, Ezequiel, would anything prevent pushing the patch to
stable team (nand entry in .dts was added in 3.14):
Fixes: 92beaccd8b49 ("ARM: mvebu: Enable NAND controller in ReadyNAS 102 .dts file")
Cheers,
a+
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