[alsa-devel] [PATCH V5 1/2] ASoC: core: add API for registering DMI card names

[Han Lu]

On 04/05/2016 01:38 PM, Takashi Sakamoto wrote:
> Hi,
>
> On Apr 5 2016 13:26, han.lu at intel.com wrote:
>> From: "Lu, Han" <han.lu at intel.com>
>>
>> Add core API for registering DMI card names, so user space utils such
>> as PA and UCM can distinguish various products.
>> Previously on ASoC, the card short name, driver name and long name are
>> all the same as the machine driver name.
>> The patch adds more board information:
>>    card driver name --->  machine driver name
>>    card short name  --->  DMI_BOARD_NAME or DMI_PRODUCT_NAME
>>    card long name and
>>    card component   --->  short name;driver name;(DMI_SYS_VENDOR,
>>                           optional);(the firmware name, optional)
>>
>> Signed-off-by: Lu, Han <han.lu at intel.com>
>>
>> diff --git a/include/sound/soc.h b/include/sound/soc.h
>> index 02b4a21..4e80444 100644
>> --- a/include/sound/soc.h
>> +++ b/include/sound/soc.h
>> @@ -486,6 +486,9 @@ void snd_soc_runtime_deactivate(struct 
>> snd_soc_pcm_runtime *rtd, int stream);
>>   int snd_soc_runtime_set_dai_fmt(struct snd_soc_pcm_runtime *rtd,
>>       unsigned int dai_fmt);
>>
>> +int snd_soc_set_card_names(struct snd_soc_card *card, const char 
>> *board,
>> +        const char *vendor, const char *firmware);
>> +
>>   /* Utility functions to get clock rates from various things */
>>   int snd_soc_calc_frame_size(int sample_size, int channels, int 
>> tdm_slots);
>>   int snd_soc_params_to_frame_size(struct snd_pcm_hw_params *params);
>> diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
>> index d2e62b15..a06b9b9 100644
>> --- a/sound/soc/soc-core.c
>> +++ b/sound/soc/soc-core.c
>> @@ -48,6 +48,9 @@
>>
>>   #define NAME_SIZE    32
>>
>> +#define LONGNAME_SIZE    80    /* size of longname[] in struct 
>> snd_card */
>> +static char card_longname[LONGNAME_SIZE];
>> +
>
> I'm not a developer for SoC sound interfaces or Skylake something, 
> however I wonder the reason to add fiile local variable for this 
> purpose. Could I request your intension about it?
>
> Here, I assume a platform with some sound intefaces (I don't know we 
> rarely have the situation or not). If several drivers are probed for 
> these interfaces, the 'snd_soc_set_card_names()' might cause a race 
> condition between the drivers against the local variable. However, 
> there's no usage of lock primitive.
> Additionally, when probing processing finishes for the second driver, 
> the local variable changes its contents. Then, ALSA core returns the 
> renewed string as the component of the first driver. This is not good.
>
> If it's too rare that a platform with several interfaces, please 
> inform it to me.
Thanks for reviewing.
I allocated an array here just intending for drivers to store 
card->long_name, since I
assumed (by mistake) that one platform has only one interface.
I'll use dynamic allocate and cleanup instead.

BR,
Han
>
>>   #ifdef CONFIG_DEBUG_FS
>>   struct dentry *snd_soc_debugfs_root;
>>   EXPORT_SYMBOL_GPL(snd_soc_debugfs_root);
>> @@ -1828,6 +1831,70 @@ int snd_soc_runtime_set_dai_fmt(struct 
>> snd_soc_pcm_runtime *rtd,
>>   }
>>   EXPORT_SYMBOL_GPL(snd_soc_runtime_set_dai_fmt);
>>
>> +/**
>> + * snd_soc_set_card_names() - Register DMI names to card
>> + * @card: The card to register DMI names
>> + * @board: DMI_BOARD_NAME or DMI_PRODUCT_NAME
>> + * @vendor: DMI_SYS_VENDOR, optional
>> + * @firmware: The firmware name, optional
>> + *
>> + * This function registers DMI names to card for the userspace to 
>> distinguish
>> + * different boards/products:
>> + *   card driver name --->  machine driver name
>> + *   card short name  --->  DMI_BOARD_NAME or DMI_PRODUCT_NAME
>> + *   card long name and
>> + *   card component   --->  short name;driver name;(DMI_SYS_VENDOR, 
>> optional)
>> + *                          ;(firmware name, optional)
>> + *
>> + * Returns 0 on success, otherwise a negative error code.
>> + */
>> +int snd_soc_set_card_names(struct snd_soc_card *card, const char 
>> *board,
>> +        const char *vendor, const char *firmware)
>> +{
>> +    int ret = 0;
>> +    size_t name_size;
>> +
>> +    if (!board) {
>> +        dev_err(card->dev, "ASoC: the board/product name is empty!\n");
>> +        return -EINVAL;
>> +    }
>> +
>> +    /* card driver name */
>> +    card->driver_name = card->name;
>> +
>> +    /* card short name */
>> +    card->name = board;
>> +
>> +    /* card long name */
>> +    name_size = strlen(card->name) + strlen(card->driver_name) + 4;
>> +    if (vendor)
>> +        name_size += strlen(vendor);
>> +    if (firmware)
>> +        name_size += strlen(firmware);
>> +    if (name_size > LONGNAME_SIZE)
>> +        return -ENOMEM;
>> +
>> +    snprintf(card_longname, LONGNAME_SIZE, "%s;%s;",
>> +            card->name, card->driver_name);
>> +    if (vendor)
>> +        strlcat(card_longname, vendor, LONGNAME_SIZE);
>> +    strlcat(card_longname, ";", LONGNAME_SIZE);
>> +    if (firmware)
>> +        strlcat(card_longname, firmware, LONGNAME_SIZE);
>> +
>> +    card->long_name = card_longname;
>> +
>> +    /* card component */
>> +    if (sizeof(card->snd_card->components) < name_size
>> +            + strlen(card->snd_card->components))
>> +        return -ENOMEM;
>> +
>> +    ret = snd_component_add(card->snd_card, card->long_name);
>> +
>> +    return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(snd_soc_set_card_names);
>> +
>>   static int snd_soc_instantiate_card(struct snd_soc_card *card)
>>   {
>>       struct snd_soc_codec *codec;
>
> Regards
>
>
> Takashi Sakamoto
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