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authorPierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>2015-02-13 15:14:03 -0600
committerTakashi Iwai <tiwai@suse.de>2015-02-20 17:30:03 +0100
commit229d043096ea8e58829d37d35767afeac15997f5 (patch)
tree36a7c15f53435696812cd8e616769f373400d027 /include
parent0c8d948565490d2a2db9d9a5aec388342c7d38ce (diff)
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 <pierre-louis.bossart@linux.intel.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'include')
-rw-r--r--include/sound/pcm.h60
-rw-r--r--include/uapi/sound/asound.h34
2 files changed, 90 insertions, 4 deletions
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;
diff --git a/include/uapi/sound/asound.h b/include/uapi/sound/asound.h
index 0e88e7a0f0eb..acef4e4d2735 100644
--- a/include/uapi/sound/asound.h
+++ b/include/uapi/sound/asound.h
@@ -267,10 +267,17 @@ typedef int __bitwise snd_pcm_subformat_t;
#define SNDRV_PCM_INFO_JOINT_DUPLEX 0x00200000 /* playback and capture stream are somewhat correlated */
#define SNDRV_PCM_INFO_SYNC_START 0x00400000 /* pcm support some kind of sync go */
#define SNDRV_PCM_INFO_NO_PERIOD_WAKEUP 0x00800000 /* period wakeup can be disabled */
-#define SNDRV_PCM_INFO_HAS_WALL_CLOCK 0x01000000 /* has audio wall clock for audio/system time sync */
+#define SNDRV_PCM_INFO_HAS_WALL_CLOCK 0x01000000 /* (Deprecated)has audio wall clock for audio/system time sync */
+#define SNDRV_PCM_INFO_HAS_LINK_ATIME 0x01000000 /* report hardware link audio time, reset on startup */
+#define SNDRV_PCM_INFO_HAS_LINK_ABSOLUTE_ATIME 0x02000000 /* report absolute hardware link audio time, not reset on startup */
+#define SNDRV_PCM_INFO_HAS_LINK_ESTIMATED_ATIME 0x04000000 /* report estimated link audio time */
+#define SNDRV_PCM_INFO_HAS_LINK_SYNCHRONIZED_ATIME 0x08000000 /* report synchronized audio/system time */
+
#define SNDRV_PCM_INFO_DRAIN_TRIGGER 0x40000000 /* internal kernel flag - trigger in drain */
#define SNDRV_PCM_INFO_FIFO_IN_FRAMES 0x80000000 /* internal kernel flag - FIFO size is in frames */
+
+
typedef int __bitwise snd_pcm_state_t;
#define SNDRV_PCM_STATE_OPEN ((__force snd_pcm_state_t) 0) /* stream is open */
#define SNDRV_PCM_STATE_SETUP ((__force snd_pcm_state_t) 1) /* stream has a setup */
@@ -408,6 +415,22 @@ struct snd_pcm_channel_info {
unsigned int step; /* samples distance in bits */
};
+enum {
+ /*
+ * first definition for backwards compatibility only,
+ * maps to wallclock/link time for HDAudio playback and DEFAULT/DMA time for everything else
+ */
+ SNDRV_PCM_AUDIO_TSTAMP_TYPE_COMPAT = 0,
+
+ /* timestamp definitions */
+ SNDRV_PCM_AUDIO_TSTAMP_TYPE_DEFAULT = 1, /* DMA time, reported as per hw_ptr */
+ SNDRV_PCM_AUDIO_TSTAMP_TYPE_LINK = 2, /* link time reported by sample or wallclock counter, reset on startup */
+ SNDRV_PCM_AUDIO_TSTAMP_TYPE_LINK_ABSOLUTE = 3, /* link time reported by sample or wallclock counter, not reset on startup */
+ SNDRV_PCM_AUDIO_TSTAMP_TYPE_LINK_ESTIMATED = 4, /* link time estimated indirectly */
+ SNDRV_PCM_AUDIO_TSTAMP_TYPE_LINK_SYNCHRONIZED = 5, /* link time synchronized with system time */
+ SNDRV_PCM_AUDIO_TSTAMP_TYPE_LAST = SNDRV_PCM_AUDIO_TSTAMP_TYPE_LINK_SYNCHRONIZED
+};
+
struct snd_pcm_status {
snd_pcm_state_t state; /* stream state */
struct timespec trigger_tstamp; /* time when stream was started/stopped/paused */
@@ -419,9 +442,11 @@ struct snd_pcm_status {
snd_pcm_uframes_t avail_max; /* max frames available on hw since last status */
snd_pcm_uframes_t overrange; /* count of ADC (capture) overrange detections from last status */
snd_pcm_state_t suspended_state; /* suspended stream state */
- __u32 reserved_alignment; /* must be filled with zero */
- struct timespec audio_tstamp; /* from sample counter or wall clock */
- unsigned char reserved[56-sizeof(struct timespec)]; /* must be filled with zero */
+ __u32 audio_tstamp_data; /* needed for 64-bit alignment, used for configs/report to/from userspace */
+ struct timespec audio_tstamp; /* sample counter, wall clock, PHC or on-demand sync'ed */
+ struct timespec driver_tstamp; /* useful in case reference system tstamp is reported with delay */
+ __u32 audio_tstamp_accuracy; /* in ns units, only valid if indicated in audio_tstamp_data */
+ unsigned char reserved[52-2*sizeof(struct timespec)]; /* must be filled with zero */
};
struct snd_pcm_mmap_status {
@@ -534,6 +559,7 @@ enum {
#define SNDRV_PCM_IOCTL_DELAY _IOR('A', 0x21, snd_pcm_sframes_t)
#define SNDRV_PCM_IOCTL_HWSYNC _IO('A', 0x22)
#define SNDRV_PCM_IOCTL_SYNC_PTR _IOWR('A', 0x23, struct snd_pcm_sync_ptr)
+#define SNDRV_PCM_IOCTL_STATUS_EXT _IOWR('A', 0x24, struct snd_pcm_status)
#define SNDRV_PCM_IOCTL_CHANNEL_INFO _IOR('A', 0x32, struct snd_pcm_channel_info)
#define SNDRV_PCM_IOCTL_PREPARE _IO('A', 0x40)
#define SNDRV_PCM_IOCTL_RESET _IO('A', 0x41)