/*
* Helper function to walk the array of sample rate triplets reported by
* the device. The problem is that we need to parse whole array first to
* get to know how many sample rates we have to expect.
* Then fp->rate_table can be allocated and filled.
*/
static int parse_uac2_sample_rate_range(struct snd_usb_audio *chip,
struct audioformat *fp, int nr_triplets,
const unsigned char *data)
{
int i, nr_rates = 0;
fp->rates = fp->rate_min = fp->rate_max = 0;
for (i = 0; i < nr_triplets; i++) {
int min = combine_quad(&data[2 + 12 * i]);
int max = combine_quad(&data[6 + 12 * i]);
int res = combine_quad(&data[10 + 12 * i]);
unsigned int rate;
if ((max < 0) || (min < 0) || (res < 0) || (max < min))
continue;
/*
* for ranges with res == 1, we announce a continuous sample
* rate range, and this function should return 0 for no further
* parsing.
*/
if (res == 1) {
fp->rate_min = min;
fp->rate_max = max;
fp->rates = SNDRV_PCM_RATE_CONTINUOUS;
return 0;
}
for (rate = min; rate <= max; rate += res) {
if (fp->rate_table)
fp->rate_table[nr_rates] = rate;
if (!fp->rate_min || rate < fp->rate_min)
fp->rate_min = rate;
if (!fp->rate_max || rate > fp->rate_max)
fp->rate_max = rate;
fp->rates |= snd_pcm_rate_to_rate_bit(rate);
nr_rates++;
if (nr_rates >= MAX_NR_RATES) {
usb_audio_err(chip, "invalid uac2 rates\n");
break;
}
/* avoid endless loop */
if (res == 0)
break;
}
}
return nr_rates;
}
unsigned int snd_usb_combine_bytes(unsigned char *bytes, int size)
{
switch (size) {
case 1: return *bytes;
case 2: return combine_word(bytes);
case 3: return combine_triple(bytes);
case 4: return combine_quad(bytes);
default: return 0;
}
}
/*
* parse the format descriptor and stores the possible sample rates
* on the audioformat table (audio class v2).
*/
static int parse_audio_format_rates_v2(struct snd_usb_audio *chip,
struct audioformat *fp,
struct usb_host_interface *iface)
{
struct usb_device *dev = chip->dev;
unsigned char tmp[2], *data;
int i, nr_rates, data_size, ret = 0;
/* get the number of sample rates first by only fetching 2 bytes */
ret = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_RANGE,
USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
UAC2_CS_CONTROL_SAM_FREQ << 8, chip->clock_id << 8,
tmp, sizeof(tmp), 1000);
if (ret < 0) {
snd_printk(KERN_ERR "unable to retrieve number of sample rates\n");
goto err;
}
nr_rates = (tmp[1] << 8) | tmp[0];
data_size = 2 + 12 * nr_rates;
data = kzalloc(data_size, GFP_KERNEL);
if (!data) {
ret = -ENOMEM;
goto err;
}
/* now get the full information */
ret = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_RANGE,
USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
UAC2_CS_CONTROL_SAM_FREQ << 8, chip->clock_id << 8,
data, data_size, 1000);
if (ret < 0) {
snd_printk(KERN_ERR "unable to retrieve sample rate range\n");
ret = -EINVAL;
goto err_free;
}
fp->rate_table = kmalloc(sizeof(int) * nr_rates, GFP_KERNEL);
if (!fp->rate_table) {
ret = -ENOMEM;
goto err_free;
}
fp->nr_rates = 0;
fp->rate_min = fp->rate_max = 0;
for (i = 0; i < nr_rates; i++) {
int rate = combine_quad(&data[2 + 12 * i]);
fp->rate_table[fp->nr_rates] = rate;
if (!fp->rate_min || rate < fp->rate_min)
fp->rate_min = rate;
if (!fp->rate_max || rate > fp->rate_max)
fp->rate_max = rate;
fp->rates |= snd_pcm_rate_to_rate_bit(rate);
fp->nr_rates++;
}
err_free:
kfree(data);
err:
return ret;
}
