[PATCH v2 5/5] mtd: core: add OTP nvmem provider support
Michael Walle
michael at walle.cc
Thu Jul 1 15:10:24 PDT 2021
Hi Guenter,
Am 2021-07-01 23:34, schrieb Guenter Roeck:
> Hi,
>
> On Sat, Apr 24, 2021 at 01:06:08PM +0200, Michael Walle wrote:
>> Flash OTP regions can already be read via user space. Some boards have
>> their serial number or MAC addresses stored in the OTP regions. Add
>> support for them being a (read-only) nvmem provider.
>>
>> The API to read the OTP data is already in place. It distinguishes
>> between factory and user OTP, thus there are up to two different
>> providers.
>>
>> Signed-off-by: Michael Walle <michael at walle.cc>
>
> This patch causes a boot failure with one of my qemu tests.
> With the patch in place, the flash fails to instantiate.
>
> [ 1.156578] Creating 3 MTD partitions on "physmap-flash":
> [ 1.157192] 0x000000000000-0x000000040000 : "U-Boot Bootloader"
> [ 1.184632] 0x000000040000-0x000000060000 : "U-Boot Environment"
> [ 1.201767] 0x000000060000-0x000000800000 : "Flash"
> [ 1.222320] Deleting MTD partitions on "physmap-flash":
> [ 1.222744] Deleting U-Boot Bootloader MTD partition
> [ 1.303597] Deleting U-Boot Environment MTD partition
> [ 1.368751] Deleting Flash MTD partition
> [ 1.430619] physmap-flash: probe of physmap-flash failed with error
> -61
>
> -61 is -ENODATA.
>
> Other boot tests with different flash chips can still boot.
> Reverting this patch (as well as the follow-up patches) fixes
> the problem.
>
> I do not know if this is a problem with qemu or a problem with the
> patch, but, as I mentioned, other flash chips do still instantiate.
>
> Do you have an idea what to look for when I try to track down the
> problem ?
I'd start by looking at the return code of mtd_otp_size() because that
should be the only function which communicates with the flash at probe
time.
Can you share how to reproduce that problem? Like the qemu commandline
and involved images?
-michael
More information about the linux-mtd
mailing list