Re: subpage reads/writes with fsl_elbc_nand driver

[Rasmus Villemoes <rasmus.villemoes@xxxxxxxxx>]

On 31/01/2019 17.11, Boris Brezillon wrote:
> On Thu, 31 Jan 2019 14:24:15 +0000
> Rasmus Villemoes <rasmus.villemoes@xxxxxxxxx> wrote:
> 
>> --- a/drivers/mtd/nand/raw/nand_base.c
>> +++ b/drivers/mtd/nand/raw/nand_base.c
>> @@ -6657,6 +6657,11 @@ static int nand_scan_tail(struct mtd_info *mtd)
>>                 pr_warn("WARNING: %s: the ECC used on your system is too
>> weak compared to the one required by the NAND chip\n",
>>                         mtd->name);
>>
>> +       if (IS_ENABLED(CONFIG_ML300PCM31)) {
>> +               pr_warn("setting NAND_NO_SUBPAGE_WRITE bit\n");
>> +               chip->ecc.write_subpage = NULL;
>> +               chip->options |= NAND_NO_SUBPAGE_WRITE;
>> +       }
>>         /* Allow subpage writes up to ecc.steps. Not possible for MLC
>> flash */
>> longer, but without the former the boot stops at
>>
>>     [    0.918927] ubi0 error: validate_ec_hdr: bad VID header offset
>> 2048, expected 512
>>     [    0.926549] ubi0 error: validate_ec_hdr: bad EC header
>>     [    0.931745] Erase counter header dump:
>>     [    0.935547]        magic          0x55424923
>>     [    0.939344]        version        1
>>     [    0.942359]        ec             9
>>     [    0.945373]        vid_hdr_offset 2048
>>     [    0.948610]        data_offset    4096
>>     [    0.951879]        image_seq      1882958541
>>     [    0.955678]        hdr_crc        0x1a47f3d3
>>     ...
>>     [    1.059976] ubi0 error: ubi_io_read_ec_hdr: validation failed for
>> PEB 0
>>     [    1.066669] ubi0 error: ubi_attach_mtd_dev: failed to attach
>> mtd0, error -22
>>     [    1.073824] UBI error: cannot attach mtd0
>>     [    1.083983] VFS: Cannot open root device "ubi0:rootfs" or
>> unknown-block(0,0): error -19
>>
> Just pass ubi.mtd=<part-name>,<page-size> on the command line. This way
> the VID header will be read/written from/to the second page instead of
> the 2nd subpage of the first page.
> 

Thanks for the quick response. I tried this, and the board does seem to
boot without the hunk above applied. Unfortunately, it seems to get
bricked after I write anything to the rootfs and reboot. I'll
investigate more thoroughly later, and also look into the conversion to
->exec_op, but for now I need to look into getting other parts of the
board working with a new kernel.

Thanks,
Rasmus
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