[alsa-devel] [PATCH v3 5/5] ALSA - hda: Add support for link audio time reporting
Takashi Iwai
tiwai at suse.de
Wed Aug 3 18:21:07 CEST 2016
On Wed, 03 Aug 2016 18:06:14 +0200,
Vinod Koul wrote:
> +static int azx_get_sync_time(ktime_t *device,
> + struct system_counterval_t *system, void *ctx)
> +{
> + struct snd_pcm_substream *substream = (struct snd_pcm_substream *)ctx;
Superfluous cast.
> + struct azx_dev *azx_dev = get_azx_dev(substream);
> + struct azx_pcm *apcm = snd_pcm_substream_chip(substream);
> + struct azx *chip = apcm->chip;
> + struct snd_pcm_runtime *runtime;
> + u64 ll_counter, ll_counter_l, ll_counter_h;
> + u64 tsc_counter, tsc_counter_l, tsc_counter_h;
> + u32 wallclk_ctr, wallclk_cycles;
> + bool direction;
> + u32 dma_select;
> + u32 timeout = 200;
> + u32 retry_count = 0;
> +
> + runtime = substream->runtime;
> +
> + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
> + direction = 1;
> + else
> + direction = 0;
> +
> + /* 0th stream tag is not used, so DMA ch 0 is for 1st stream tag */
> + do {
> + timeout = 100;
> + dma_select = (direction << GTSCC_CDMAS_DMA_DIR_SHIFT) |
> + (azx_dev->core.stream_tag - 1);
> + _snd_hdac_chip_write(l, azx_bus(chip), AZX_REG_GTSCC,
> + dma_select);
You can use
snd_hdac_chip_writel(azx_bus(chip), GTSCC, dma_select);
The use of _snd_hdac_chip_write() is for non-constant registers. When
you pass AZX_REG_XXX, you can use the standard macro. For example:
> + /* Enable the capture */
> + _snd_hdac_chip_write(l, azx_bus(chip), AZX_REG_GTSCC,
> + _snd_hdac_chip_read(l, azx_bus(chip),
> + AZX_REG_GTSCC) | GTSCC_TSCCI_MASK);
This can be simplified with snd_hdac_chip_updatel().
> +
> + while (timeout) {
> + if (_snd_hdac_chip_read(l, azx_bus(chip),
> + AZX_REG_GTSCC) & GTSCC_TSCCD_MASK)
> + break;
> + timeout--;
> + }
> +
> + if (!timeout) {
> + dev_err(chip->card->dev, "GTSCC capture Timedout!\n");
> + return -EIO;
> + }
> +
> + /* Read wall clock counter */
> + wallclk_ctr = _snd_hdac_chip_read(l, azx_bus(chip),
> + AZX_REG_WALFCC);
> +
> + /* Read TSC counter */
> + tsc_counter_l = _snd_hdac_chip_read(l, azx_bus(chip),
> + AZX_REG_TSCCL);
> + tsc_counter_h = _snd_hdac_chip_read(l, azx_bus(chip),
> + AZX_REG_TSCCU);
> +
> + /* Read Link counter */
> + ll_counter_l = _snd_hdac_chip_read(l, azx_bus(chip),
> + AZX_REG_LLPCL);
> + ll_counter_h = _snd_hdac_chip_read(l, azx_bus(chip),
> + AZX_REG_LLPCU);
> +
> + /* Ack: registers read done */
> + _snd_hdac_chip_write(l, azx_bus(chip),
> + AZX_REG_GTSCC,
> + (0x1 << GTSCC_TSCCD_SHIFT));
> +
> + tsc_counter = (tsc_counter_h << TSCCU_CCU_SHIFT) |
> + tsc_counter_l;
> +
> + ll_counter = (ll_counter_h << LLPC_CCU_SHIFT) | ll_counter_l;
> + wallclk_cycles = wallclk_ctr & WALFCC_CIF_MASK;
> +
> + /*
> + * An error occurs near frame "rollover". The clocks in
> + * frame value indicates whether this error may have
> + * occurred. Here we use the value of 10 i.e.,
> + * HDA_MAX_CYCLE_OFFSET
> + */
> + if (wallclk_cycles < HDA_MAX_CYCLE_VALUE - HDA_MAX_CYCLE_OFFSET
> + && wallclk_cycles > HDA_MAX_CYCLE_OFFSET)
> + break;
> +
> + /*
> + * Sleep before we read again, else we may again get
> + * value near to MAX_CYCLE. Try to sleep for different
> + * amount of time so we dont hit the same number again
> + */
> + udelay(retry_count++);
> +
> + } while (retry_count != HDA_MAX_CYCLE_READ_RETRY);
> +
> + if (retry_count == HDA_MAX_CYCLE_READ_RETRY) {
> + dev_err(chip->card->dev, "Error in WALFCC cycle count\n");
Hrm, this has a danger to spew huge amount of error messages, since
this gets called so often.
> + return -EIO;
> + }
> +
> + *device = ns_to_ktime(azx_scale64(ll_counter,
> + NSEC_PER_SEC, runtime->rate));
> + *device = ktime_add_ns(*device, (wallclk_cycles * NSEC_PER_SEC) /
> + ((HDA_MAX_CYCLE_VALUE + 1) * runtime->rate));
> +
> + *system = convert_art_to_tsc(tsc_counter);
> +
> + return 0;
> +}
> +
> +#else
> +static int azx_get_sync_time(ktime_t *device,
> + struct system_counterval_t *system, void *ctx)
> +{
> + return -ENXIO;
> +}
> +#endif
> +
> +static int azx_get_crosststamp(struct snd_pcm_substream *substream,
> + struct system_device_crosststamp *xtstamp)
> +{
> + return get_device_system_crosststamp(azx_get_sync_time,
> + substream, NULL, xtstamp);
> +}
> +
> static int azx_get_time_info(struct snd_pcm_substream *substream,
> struct timespec *system_ts, struct timespec *audio_ts,
> struct snd_pcm_audio_tstamp_config *audio_tstamp_config,
> struct snd_pcm_audio_tstamp_report *audio_tstamp_report)
> {
> struct azx_dev *azx_dev = get_azx_dev(substream);
> + struct snd_pcm_runtime *runtime = substream->runtime;
> + struct system_device_crosststamp xtstamp;
> u64 nsec;
>
> if ((substream->runtime->hw.info & SNDRV_PCM_INFO_HAS_LINK_ATIME) &&
> @@ -361,8 +524,38 @@ static int azx_get_time_info(struct snd_pcm_substream *substream,
> audio_tstamp_report->accuracy_report = 1; /* rest of structure is valid */
> audio_tstamp_report->accuracy = 42; /* 24 MHz WallClock == 42ns resolution */
>
> - } else
> + } else if ((runtime->hw.info &
> + SNDRV_PCM_INFO_HAS_LINK_SYNCHRONIZED_ATIME) &&
> + (audio_tstamp_config->type_requested ==
> + SNDRV_PCM_AUDIO_TSTAMP_TYPE_LINK_SYNCHRONIZED)) {
The indentation is hard to follow here...
> +
> + azx_get_crosststamp(substream, &xtstamp);
No error check?
thanks,
Takashi
> +
> + switch (runtime->tstamp_type) {
> + case SNDRV_PCM_TSTAMP_TYPE_MONOTONIC:
> + return -EINVAL;
> +
> + case SNDRV_PCM_TSTAMP_TYPE_MONOTONIC_RAW:
> + *system_ts = ktime_to_timespec(xtstamp.sys_monoraw);
> + break;
> +
> + default:
> + *system_ts = ktime_to_timespec(xtstamp.sys_realtime);
> + break;
> +
> + }
> +
> + *audio_ts = ktime_to_timespec(xtstamp.device);
> +
> + audio_tstamp_report->actual_type =
> + SNDRV_PCM_AUDIO_TSTAMP_TYPE_LINK_SYNCHRONIZED;
> + audio_tstamp_report->accuracy_report = 1;
> + /* 24 MHz WallClock == 42ns resolution */
> + audio_tstamp_report->accuracy = 42;
> +
> + } else {
> audio_tstamp_report->actual_type = SNDRV_PCM_AUDIO_TSTAMP_TYPE_DEFAULT;
> + }
>
> return 0;
> }
> --
> 1.9.1
>
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