[PATCH] mtd: dc21285: fix bytewise memcpy()

[Arnd Bergmann]

On Thu, Aug 7, 2025, at 09:54, Miquel Raynal wrote:
>
> On 07/08/2025 at 09:20:34 +02, Arnd Bergmann <arnd at kernel.org> wrote:
>
>> From: Arnd Bergmann <arnd at arndb.de>
>>
>> The commit that split up the 8/16/32-bit operations in 2004 seems to have
>> broken the 8-bit case, as clang-21 now points out:
>>
>> drivers/mtd/maps/dc21285.c:129:97: error: parameter 'len' set but not used [-Werror,-Wunused-but-set-parameter]
>>   129 | static void dc21285_copy_to_8(struct map_info *map, unsigned long to, const void *from, ssize_t len)
>>
>> Put back the loop that was in linux-2.6.8 and earlier for this case.
>>
>> Fixes: 67d4878e4e61 ("NOR flash drivers update")
>> Cc: David Woodhouse <dwmw2 at infradead.org>
>> Signed-off-by: Arnd Bergmann <arnd at arndb.de>
>
> Thanks for the patch, I'll take it, but that probably means few to no
> people still use it, if broken for more than 20 years...

Yes, certainly. I also have a patch to mark the mach-footbridge
platform as deprecated and schedule it for removal, I need to
resend that patch.

What I suspect happened here is that the bug was harmless
because the few boards that use this driver all have
16-bit or 32-bit flashes, while the 8-bit codepath was indeed
unused.

    Arnd