Re: [PATCH 1/7] ALSA: firewire-tascam: add skeleton for TASCAM FireWire series

[Takashi Sakamoto <o-takashi@sakamocchi.jp>]

Hi,

On Oct 13 2015 03:47, Clemens Ladisch wrote:
> Takashi Iwai wrote:
>> kbuild test robot wrote:
>>>>> sound/firewire/tascam/tascam.c:23:16: sparse: cast to restricted __be32
>>>
>>>   > 23		data = be32_to_cpu(fw_dev->config_rom[28]);
>>
>> The code itself looks correct.  data is CPU endian.
>> The problem looks rather like that fw_dev->config_rom[] is u32.
>>
>> Stefan, can it be changed to __be32 instead?
> 
> config_rom[] is CPU endian, too.
> 
> Strings should be read with fw_csr_string().

The function is designed for IEEE 1212 compliant config ROM. On the
other hand, config ROMs of these models are not fully compliant. See:

http://sourceforge.net/p/linux1394/mailman/message/33899800/

Currently, this driver supports just two models. These two models have
similar structure in their config ROM, fortunately. Thus, it's
reasonable for the driver to get information in hard-coded position of
config ROM.


About using 'be32_to_cpu()', the 'config_rom' member actually has 'const
u32 *', while in the member caracters in the textual leaf are aligned in
big-endian. I selected the simplest way to pick it up.

If it's preferrable to suppress the sparse warnings, I don't mind to
replace these codes with the other ways.


Regards

Takashi Sakamoto