[alsa-devel] [PATCH 08/13] ALSA: dice: Add new functions for limitation of PCM parameters
Takashi Sakamoto
o-takashi at sakamocchi.jp
Sun Sep 28 17:58:18 CEST 2014
This commit adds a new functions and some arrangement for PCM limitation.
This arrangement is due to the number of channels which each Dice device has.
I note that minimum number for period becomes 2, instead of 1 because its PCM
functionality has SNDRV_PCM_INFO_BATCH, this means that the driver uses double
(or more) buffering so the minimum number for period should be 2.
Signed-off-by: Takashi Sakamoto <o-takashi at sakamocchi.jp>
---
sound/firewire/dice/dice-pcm.c | 109 +++++++++++++++++++++++++----------------
1 file changed, 66 insertions(+), 43 deletions(-)
diff --git a/sound/firewire/dice/dice-pcm.c b/sound/firewire/dice/dice-pcm.c
index beff320..2e531bd 100644
--- a/sound/firewire/dice/dice-pcm.c
+++ b/sound/firewire/dice/dice-pcm.c
@@ -67,69 +67,92 @@ static int dice_channels_constraint(struct snd_pcm_hw_params *params,
return snd_interval_refine(c, &channels);
}
-
-static int pcm_open(struct snd_pcm_substream *substream)
+static void limit_channels_and_rates(struct snd_dice *dice,
+ struct snd_pcm_runtime *runtime,
+ unsigned int *pcm_channels)
{
- static const struct snd_pcm_hardware hardware = {
- .info = SNDRV_PCM_INFO_MMAP |
- SNDRV_PCM_INFO_MMAP_VALID |
- SNDRV_PCM_INFO_BATCH |
- SNDRV_PCM_INFO_INTERLEAVED |
- SNDRV_PCM_INFO_BLOCK_TRANSFER,
- .formats = AMDTP_OUT_PCM_FORMAT_BITS,
- .channels_min = UINT_MAX,
- .channels_max = 0,
- .buffer_bytes_max = 16 * 1024 * 1024,
- .period_bytes_min = 1,
- .period_bytes_max = UINT_MAX,
- .periods_min = 1,
- .periods_max = UINT_MAX,
- };
- struct snd_dice *dice = substream->private_data;
- struct snd_pcm_runtime *runtime = substream->runtime;
- unsigned int i;
- int err;
+ struct snd_pcm_hardware *hw = &runtime->hw;
+ unsigned int i, rate, mode;
- err = snd_dice_stream_lock_try(dice);
- if (err < 0)
- goto error;
+ hw->channels_min = UINT_MAX;
+ hw->channels_max = 0;
+
+ for (i = 0; i < ARRAY_SIZE(snd_dice_rates); ++i) {
+ rate = snd_dice_rates[i];
+ if (snd_dice_stream_get_rate_mode(dice, rate, &mode) < 0)
+ continue;
+ hw->rates |= snd_pcm_rate_to_rate_bit(rate);
- runtime->hw = hardware;
+ if (pcm_channels[mode] == 0)
+ continue;
+ hw->channels_min = min(hw->channels_min, pcm_channels[mode]);
+ hw->channels_max = max(hw->channels_max, pcm_channels[mode]);
+ }
- for (i = 0; i < ARRAY_SIZE(snd_dice_rates); ++i)
- if (dice->clock_caps & (1 << i))
- runtime->hw.rates |=
- snd_pcm_rate_to_rate_bit(snd_dice_rates[i]);
snd_pcm_limit_hw_rates(runtime);
+}
- for (i = 0; i < 3; ++i)
- if (dice->rx_channels[i]) {
- runtime->hw.channels_min = min(runtime->hw.channels_min,
- dice->rx_channels[i]);
- runtime->hw.channels_max = max(runtime->hw.channels_max,
- dice->rx_channels[i]);
- }
+static void limit_period_and_buffer(struct snd_pcm_hardware *hw)
+{
+ hw->periods_min = 2; /* SNDRV_PCM_INFO_BATCH */
+ hw->periods_max = UINT_MAX;
+
+ hw->period_bytes_min = 4 * hw->channels_max; /* byte for a frame */
+
+ /* Just to prevent from allocating much pages. */
+ hw->period_bytes_max = hw->period_bytes_min * 2048;
+ hw->buffer_bytes_max = hw->period_bytes_max * hw->periods_min;
+}
+
+static int init_hw_info(struct snd_dice *dice,
+ struct snd_pcm_substream *substream)
+{
+ struct snd_pcm_runtime *runtime = substream->runtime;
+ struct snd_pcm_hardware *hw = &runtime->hw;
+ int err;
+
+ hw->info = SNDRV_PCM_INFO_MMAP |
+ SNDRV_PCM_INFO_MMAP_VALID |
+ SNDRV_PCM_INFO_BATCH |
+ SNDRV_PCM_INFO_INTERLEAVED |
+ SNDRV_PCM_INFO_BLOCK_TRANSFER;
+ hw->formats = AMDTP_OUT_PCM_FORMAT_BITS;
+
+ limit_channels_and_rates(dice, runtime, dice->rx_channels);
+ limit_period_and_buffer(hw);
err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
dice_rate_constraint, dice,
SNDRV_PCM_HW_PARAM_CHANNELS, -1);
if (err < 0)
- goto err_lock;
+ goto end;
err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
dice_channels_constraint, dice,
SNDRV_PCM_HW_PARAM_RATE, -1);
if (err < 0)
- goto err_lock;
+ goto end;
err = amdtp_stream_add_pcm_hw_constraints(&dice->rx_stream, runtime);
- if (err < 0)
- goto err_lock;
+end:
+ return err;
+}
- return 0;
+static int pcm_open(struct snd_pcm_substream *substream)
+{
+ struct snd_dice *dice = substream->private_data;
+ int err;
-err_lock:
+ err = snd_dice_stream_lock_try(dice);
+ if (err < 0)
+ goto end;
+
+ err = init_hw_info(dice, substream);
+ if (err < 0)
+ goto err_locked;
+end:
+ return err;
+err_locked:
snd_dice_stream_lock_release(dice);
-error:
return err;
}
--
1.9.1
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