From 229d043096ea8e58829d37d35767afeac15997f5 Mon Sep 17 00:00:00 2001 From: Pierre-Louis Bossart Date: Fri, 13 Feb 2015 15:14:03 -0600 Subject: ALSA: core: selection of audio_tstamp type and accuracy reports Audio timestamps can be extracted from sample counters, wall clocks, PHC clocks (Ethernet AVB), on-demand synchronized snapshots. This patch provides the ability to report timestamping capabilities, select timestamp types and retrieve timestamp accuracy, if supported. Details can be found in Documentations/sound/alsa/timestamping.txt This functionality is introduced by reclaiming the reserved_aligned field introduced by commit9c7066aef4a5eb8e4063de28f06c508bf6f2963a in snd_pcm_status to provide userspace with selection/query capabilities. Additional driver_tstamp and audio_tstamp_accuracy fields are also added. snd_pcm_mmap_status remains a read-only structure with only the audio timestamp value accessible from user space. The selection of audio timestamp type is done through snd_pcm_status only This commit does not impact ABI and does not impact the default behavior. By default audio timestamp is aligned with hw_pointer and reports the DMA position. Backwards compatibility is handled by using the HDAudio wall clock for playback and the hw_ptr for all other cases. For timestamp selection a new STATUS_EXT ioctl is introduced with read/write parameters. Alsa-lib will be modified to make use of STATUS_EXT. Signed-off-by: Pierre-Louis Bossart Signed-off-by: Takashi Iwai --- include/sound/pcm.h | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 60 insertions(+) (limited to 'include/sound') diff --git a/include/sound/pcm.h b/include/sound/pcm.h index c0ddb7e69c28..60f0e48f7905 100644 --- a/include/sound/pcm.h +++ b/include/sound/pcm.h @@ -60,6 +60,9 @@ struct snd_pcm_hardware { struct snd_pcm_substream; +struct snd_pcm_audio_tstamp_config; /* definitions further down */ +struct snd_pcm_audio_tstamp_report; + struct snd_pcm_ops { int (*open)(struct snd_pcm_substream *substream); int (*close)(struct snd_pcm_substream *substream); @@ -281,6 +284,58 @@ struct snd_pcm_hw_constraint_ranges { struct snd_pcm_hwptr_log; +/* + * userspace-provided audio timestamp config to kernel, + * structure is for internal use only and filled with dedicated unpack routine + */ +struct snd_pcm_audio_tstamp_config { + /* 5 of max 16 bits used */ + u32 type_requested:4; + u32 report_delay:1; /* add total delay to A/D or D/A */ +}; + +static inline void snd_pcm_unpack_audio_tstamp_config(__u32 data, + struct snd_pcm_audio_tstamp_config *config) +{ + config->type_requested = data & 0xF; + config->report_delay = (data >> 4) & 1; +} + +/* + * kernel-provided audio timestamp report to user-space + * structure is for internal use only and read by dedicated pack routine + */ +struct snd_pcm_audio_tstamp_report { + /* 6 of max 16 bits used for bit-fields */ + + /* for backwards compatibility */ + u32 valid:1; + + /* actual type if hardware could not support requested timestamp */ + u32 actual_type:4; + + /* accuracy represented in ns units */ + u32 accuracy_report:1; /* 0 if accuracy unknown, 1 if accuracy field is valid */ + u32 accuracy; /* up to 4.29s, will be packed in separate field */ +}; + +static inline void snd_pcm_pack_audio_tstamp_report(__u32 *data, __u32 *accuracy, + const struct snd_pcm_audio_tstamp_report *report) +{ + u32 tmp; + + tmp = report->accuracy_report; + tmp <<= 4; + tmp |= report->actual_type; + tmp <<= 1; + tmp |= report->valid; + + *data &= 0xffff; /* zero-clear MSBs */ + *data |= (tmp << 16); + *accuracy = report->accuracy; +} + + struct snd_pcm_runtime { /* -- Status -- */ struct snd_pcm_substream *trigger_master; @@ -361,6 +416,11 @@ struct snd_pcm_runtime { struct snd_dma_buffer *dma_buffer_p; /* allocated buffer */ + /* -- audio timestamp config -- */ + struct snd_pcm_audio_tstamp_config audio_tstamp_config; + struct snd_pcm_audio_tstamp_report audio_tstamp_report; + struct timespec driver_tstamp; + #if defined(CONFIG_SND_PCM_OSS) || defined(CONFIG_SND_PCM_OSS_MODULE) /* -- OSS things -- */ struct snd_pcm_oss_runtime oss; -- cgit v1.2.3 From 3179f62001880e588e229db3006a59ad87b7792a Mon Sep 17 00:00:00 2001 From: Pierre-Louis Bossart Date: Fri, 13 Feb 2015 15:14:06 -0600 Subject: ALSA: core: add .get_time_info Introduce more generic .get_time_info to retrieve system timestamp and audio timestamp in single routine. Backwards compatibility is preserved with same functionality as with .wall_clock method (to be removed in following commits to avoid breaking git bisect) Signed-off-by: Pierre-Louis Bossart Signed-off-by: Takashi Iwai --- include/sound/pcm.h | 4 +++ sound/core/pcm_lib.c | 88 +++++++++++++++++++++++++++++++++---------------- sound/core/pcm_native.c | 24 ++++++++++++++ 3 files changed, 87 insertions(+), 29 deletions(-) (limited to 'include/sound') diff --git a/include/sound/pcm.h b/include/sound/pcm.h index 60f0e48f7905..04f2d492ae57 100644 --- a/include/sound/pcm.h +++ b/include/sound/pcm.h @@ -76,6 +76,10 @@ struct snd_pcm_ops { snd_pcm_uframes_t (*pointer)(struct snd_pcm_substream *substream); int (*wall_clock)(struct snd_pcm_substream *substream, struct timespec *audio_ts); + int (*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); int (*copy)(struct snd_pcm_substream *substream, int channel, snd_pcm_uframes_t pos, void __user *buf, snd_pcm_uframes_t count); diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c index ffd656012ab8..ac6b33f3779c 100644 --- a/sound/core/pcm_lib.c +++ b/sound/core/pcm_lib.c @@ -232,6 +232,49 @@ int snd_pcm_update_state(struct snd_pcm_substream *substream, return 0; } +static void update_audio_tstamp(struct snd_pcm_substream *substream, + struct timespec *curr_tstamp, + struct timespec *audio_tstamp) +{ + struct snd_pcm_runtime *runtime = substream->runtime; + u64 audio_frames, audio_nsecs; + struct timespec driver_tstamp; + + if (runtime->tstamp_mode != SNDRV_PCM_TSTAMP_ENABLE) + return; + + if (!(substream->ops->get_time_info) || + (runtime->audio_tstamp_report.actual_type == + SNDRV_PCM_AUDIO_TSTAMP_TYPE_DEFAULT)) { + + /* + * provide audio timestamp derived from pointer position + * add delay only if requested + */ + + audio_frames = runtime->hw_ptr_wrap + runtime->status->hw_ptr; + + if (runtime->audio_tstamp_config.report_delay) { + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) + audio_frames -= runtime->delay; + else + audio_frames += runtime->delay; + } + audio_nsecs = div_u64(audio_frames * 1000000000LL, + runtime->rate); + *audio_tstamp = ns_to_timespec(audio_nsecs); + } + runtime->status->audio_tstamp = *audio_tstamp; + runtime->status->tstamp = *curr_tstamp; + + /* + * re-take a driver timestamp to let apps detect if the reference tstamp + * read by low-level hardware was provided with a delay + */ + snd_pcm_gettime(substream->runtime, (struct timespec *)&driver_tstamp); + runtime->driver_tstamp = driver_tstamp; +} + static int snd_pcm_update_hw_ptr0(struct snd_pcm_substream *substream, unsigned int in_interrupt) { @@ -256,11 +299,18 @@ static int snd_pcm_update_hw_ptr0(struct snd_pcm_substream *substream, pos = substream->ops->pointer(substream); curr_jiffies = jiffies; if (runtime->tstamp_mode == SNDRV_PCM_TSTAMP_ENABLE) { - snd_pcm_gettime(runtime, (struct timespec *)&curr_tstamp); - - if ((runtime->hw.info & SNDRV_PCM_INFO_HAS_WALL_CLOCK) && - (substream->ops->wall_clock)) - substream->ops->wall_clock(substream, &audio_tstamp); + if ((substream->ops->get_time_info) && + (runtime->audio_tstamp_config.type_requested != SNDRV_PCM_AUDIO_TSTAMP_TYPE_DEFAULT)) { + substream->ops->get_time_info(substream, &curr_tstamp, + &audio_tstamp, + &runtime->audio_tstamp_config, + &runtime->audio_tstamp_report); + + /* re-test in case tstamp type is not supported in hardware and was demoted to DEFAULT */ + if (runtime->audio_tstamp_report.actual_type == SNDRV_PCM_AUDIO_TSTAMP_TYPE_DEFAULT) + snd_pcm_gettime(runtime, (struct timespec *)&curr_tstamp); + } else + snd_pcm_gettime(runtime, (struct timespec *)&curr_tstamp); } if (pos == SNDRV_PCM_POS_XRUN) { @@ -403,8 +453,10 @@ static int snd_pcm_update_hw_ptr0(struct snd_pcm_substream *substream, } no_delta_check: - if (runtime->status->hw_ptr == new_hw_ptr) + if (runtime->status->hw_ptr == new_hw_ptr) { + update_audio_tstamp(substream, &curr_tstamp, &audio_tstamp); return 0; + } if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK && runtime->silence_size > 0) @@ -426,30 +478,8 @@ static int snd_pcm_update_hw_ptr0(struct snd_pcm_substream *substream, snd_BUG_ON(crossed_boundary != 1); runtime->hw_ptr_wrap += runtime->boundary; } - if (runtime->tstamp_mode == SNDRV_PCM_TSTAMP_ENABLE) { - runtime->status->tstamp = curr_tstamp; - if (!(runtime->hw.info & SNDRV_PCM_INFO_HAS_WALL_CLOCK)) { - /* - * no wall clock available, provide audio timestamp - * derived from pointer position+delay - */ - u64 audio_frames, audio_nsecs; - - if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) - audio_frames = runtime->hw_ptr_wrap - + runtime->status->hw_ptr - - runtime->delay; - else - audio_frames = runtime->hw_ptr_wrap - + runtime->status->hw_ptr - + runtime->delay; - audio_nsecs = div_u64(audio_frames * 1000000000LL, - runtime->rate); - audio_tstamp = ns_to_timespec(audio_nsecs); - } - runtime->status->audio_tstamp = audio_tstamp; - } + update_audio_tstamp(substream, &curr_tstamp, &audio_tstamp); return snd_pcm_update_state(substream, runtime); } diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c index 72323a8c35c8..9c2c6f801fed 100644 --- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -707,6 +707,23 @@ int snd_pcm_status(struct snd_pcm_substream *substream, struct snd_pcm_runtime *runtime = substream->runtime; snd_pcm_stream_lock_irq(substream); + + snd_pcm_unpack_audio_tstamp_config(status->audio_tstamp_data, + &runtime->audio_tstamp_config); + + /* backwards compatible behavior */ + if (runtime->audio_tstamp_config.type_requested == + SNDRV_PCM_AUDIO_TSTAMP_TYPE_COMPAT) { + if (runtime->hw.info & SNDRV_PCM_INFO_HAS_WALL_CLOCK) + runtime->audio_tstamp_config.type_requested = + SNDRV_PCM_AUDIO_TSTAMP_TYPE_LINK; + else + runtime->audio_tstamp_config.type_requested = + SNDRV_PCM_AUDIO_TSTAMP_TYPE_DEFAULT; + runtime->audio_tstamp_report.valid = 0; + } else + runtime->audio_tstamp_report.valid = 1; + status->state = runtime->status->state; status->suspended_state = runtime->status->suspended_state; if (status->state == SNDRV_PCM_STATE_OPEN) @@ -716,8 +733,15 @@ int snd_pcm_status(struct snd_pcm_substream *substream, snd_pcm_update_hw_ptr(substream); if (runtime->tstamp_mode == SNDRV_PCM_TSTAMP_ENABLE) { status->tstamp = runtime->status->tstamp; + status->driver_tstamp = runtime->driver_tstamp; status->audio_tstamp = runtime->status->audio_tstamp; + if (runtime->audio_tstamp_report.valid == 1) + /* backwards compatibility, no report provided in COMPAT mode */ + snd_pcm_pack_audio_tstamp_report(&status->audio_tstamp_data, + &status->audio_tstamp_accuracy, + &runtime->audio_tstamp_report); + goto _tstamp_end; } } else { -- cgit v1.2.3 From 2d52a5abd5be35340296a251092c8a594679df54 Mon Sep 17 00:00:00 2001 From: Pierre-Louis Bossart Date: Fri, 13 Feb 2015 15:14:08 -0600 Subject: ALSA: core: remove .wall_clock can be removed without breaking git-bisect now Signed-off-by: Pierre-Louis Bossart Signed-off-by: Takashi Iwai --- include/sound/pcm.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'include/sound') diff --git a/include/sound/pcm.h b/include/sound/pcm.h index 04f2d492ae57..0cb7f3f5df7b 100644 --- a/include/sound/pcm.h +++ b/include/sound/pcm.h @@ -74,8 +74,6 @@ struct snd_pcm_ops { int (*prepare)(struct snd_pcm_substream *substream); int (*trigger)(struct snd_pcm_substream *substream, int cmd); snd_pcm_uframes_t (*pointer)(struct snd_pcm_substream *substream); - int (*wall_clock)(struct snd_pcm_substream *substream, - struct timespec *audio_ts); int (*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, -- cgit v1.2.3