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

[Takashi Sakamoto]

On 2015年10月03日 18:14, Clemens Ladisch wrote:
> Takashi Sakamoto wrote:
>>>>> 23		data = be32_to_cpu(fw_dev->config_rom[28]);
>>
>> 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.
> 
> Strictly speaking, strings do not have an endianness.
> 
> Most data in the actual configuration ROM is organized as big-endian 32-
> bit values, so the FireWire core converts _all_ words from big endian to
> CPU endian.  The words that are not actually 32-bit values but strings
> have to be converted back; the correct function for this is cpu_to_be32().

Yes. And I forgot a pair of cpu_to_be32/be32_to_cpu is symmetric each other!
(I'm really a stupid guy, sigh...)

This patch solves the sparce warnings.

$ git diff
diff --git a/sound/firewire/tascam/tascam.c b/sound/firewire/tascam/tascam.c
index ee2f498..6e1087e 100644
--- a/sound/firewire/tascam/tascam.c
+++ b/sound/firewire/tascam/tascam.c
@@ -50,19 +50,19 @@ static int check_name(struct snd_tscm *tscm)
        struct fw_device *fw_dev = fw_parent_device(tscm->unit);
        char vendor[8];
        char model[8];
-       __u32 data;
+       __be32 data;

        /* Retrieve model name. */
-       data = be32_to_cpu(fw_dev->config_rom[28]);
+       data = cpu_to_be32(fw_dev->config_rom[28]);
        memcpy(model, &data, 4);
-       data = be32_to_cpu(fw_dev->config_rom[29]);
+       data = cpu_to_be32(fw_dev->config_rom[29]);
        memcpy(model + 4, &data, 4);
        model[7] = '\0';

        /* Retrieve vendor name. */
-       data = be32_to_cpu(fw_dev->config_rom[23]);
+       data = cpu_to_be32(fw_dev->config_rom[23]);
        memcpy(vendor, &data, 4);
-       data = be32_to_cpu(fw_dev->config_rom[24]);
+       data = cpu_to_be32(fw_dev->config_rom[24]);
        memcpy(vendor + 4, &data, 4);
        vendor[7] = '\0';


> Iwai-san,

Should I re-post this patchset? Or you kindly merge them with your
modification?


Regards

Takashi Sakamoto