---

yaml
---
r: 342563
b: refs/heads/master
c: 5d890f5
h: refs/heads/master
i:
  342561: 3eb76fd
  342559: a14ec5f
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 4eeaaeaea1cec60a25979678182720dc91308550
+refs/heads/master: 5d890f591d15d1161131546c2af371178c967734

trunk/sound/pci/hda/hda_intel.c

@@ -47,6 +47,9 @@
 #include <linux/reboot.h>
 #include <linux/io.h>
 #include <linux/pm_runtime.h>
+#include <linux/clocksource.h>
+#include <linux/time.h>
+
 #ifdef CONFIG_X86
 /* for snoop control */
 #include <asm/pgtable.h>
@@ -419,6 +422,9 @@ struct azx_dev {
 	unsigned int insufficient :1;
 	unsigned int wc_marked:1;
 	unsigned int no_period_wakeup:1;
+
+	struct timecounter  azx_tc;
+	struct cyclecounter azx_cc;
 };
 
 /* CORB/RIRB */
@@ -1749,6 +1755,64 @@ static inline void azx_release_device(struct azx_dev *azx_dev)
 	azx_dev->opened = 0;
 }
 
+static cycle_t azx_cc_read(const struct cyclecounter *cc)
+{
+	struct azx_dev *azx_dev = container_of(cc, struct azx_dev, azx_cc);
+	struct snd_pcm_substream *substream = azx_dev->substream;
+	struct azx_pcm *apcm = snd_pcm_substream_chip(substream);
+	struct azx *chip = apcm->chip;
+
+	return azx_readl(chip, WALLCLK);
+}
+
+static void azx_timecounter_init(struct snd_pcm_substream *substream,
+				bool force, cycle_t last)
+{
+	struct azx_dev *azx_dev = get_azx_dev(substream);
+	struct timecounter *tc = &azx_dev->azx_tc;
+	struct cyclecounter *cc = &azx_dev->azx_cc;
+	u64 nsec;
+
+	cc->read = azx_cc_read;
+	cc->mask = CLOCKSOURCE_MASK(32);
+
+	/*
+	 * Converting from 24 MHz to ns means applying a 125/3 factor.
+	 * To avoid any saturation issues in intermediate operations,
+	 * the 125 factor is applied first. The division is applied
+	 * last after reading the timecounter value.
+	 * Applying the 1/3 factor as part of the multiplication
+	 * requires at least 20 bits for a decent precision, however
+	 * overflows occur after about 4 hours or less, not a option.
+	 */
+
+	cc->mult = 125; /* saturation after 195 years */
+	cc->shift = 0;
+
+	nsec = 0; /* audio time is elapsed time since trigger */
+	timecounter_init(tc, cc, nsec);
+	if (force)
+		/*
+		 * force timecounter to use predefined value,
+		 * used for synchronized starts
+		 */
+		tc->cycle_last = last;
+}
+
+static int azx_get_wallclock_tstamp(struct snd_pcm_substream *substream,
+				struct timespec *ts)
+{
+	struct azx_dev *azx_dev = get_azx_dev(substream);
+	u64 nsec;
+
+	nsec = timecounter_read(&azx_dev->azx_tc);
+	nsec = div_u64(nsec, 3); /* can be optimized */
+
+	*ts = ns_to_timespec(nsec);
+
+	return 0;
+}
+
 static struct snd_pcm_hardware azx_pcm_hw = {
 	.info =			(SNDRV_PCM_INFO_MMAP |
 				 SNDRV_PCM_INFO_INTERLEAVED |
@@ -1758,6 +1822,7 @@ static struct snd_pcm_hardware azx_pcm_hw = {
 				 /* SNDRV_PCM_INFO_RESUME |*/
 				 SNDRV_PCM_INFO_PAUSE |
 				 SNDRV_PCM_INFO_SYNC_START |
+				 SNDRV_PCM_INFO_HAS_WALL_CLOCK |
 				 SNDRV_PCM_INFO_NO_PERIOD_WAKEUP),
 	.formats =		SNDRV_PCM_FMTBIT_S16_LE,
 	.rates =		SNDRV_PCM_RATE_48000,
@@ -1797,6 +1862,12 @@ static int azx_pcm_open(struct snd_pcm_substream *substream)
 	runtime->hw.rates = hinfo->rates;
 	snd_pcm_limit_hw_rates(runtime);
 	snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
+
+	/* avoid wrap-around with wall-clock */
+	snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_BUFFER_TIME,
+				20,
+				178000000);
+
 	if (chip->align_buffer_size)
 		/* constrain buffer sizes to be multiple of 128
 		   bytes. This is more efficient in terms of memory
@@ -1836,6 +1907,12 @@ static int azx_pcm_open(struct snd_pcm_substream *substream)
 		mutex_unlock(&chip->open_mutex);
 		return -EINVAL;
 	}
+
+	/* disable WALLCLOCK timestamps for capture streams
+	   until we figure out how to handle digital inputs */
+	if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
+		runtime->hw.info &= ~SNDRV_PCM_INFO_HAS_WALL_CLOCK;
+
 	spin_lock_irqsave(&chip->reg_lock, flags);
 	azx_dev->substream = substream;
 	azx_dev->running = 0;
@@ -2072,6 +2149,22 @@ static int azx_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
 			azx_readl(chip, OLD_SSYNC) & ~sbits);
 	else
 		azx_writel(chip, SSYNC, azx_readl(chip, SSYNC) & ~sbits);
+	if (start) {
+		azx_timecounter_init(substream, 0, 0);
+		if (nsync > 1) {
+			cycle_t cycle_last;
+
+			/* same start cycle for master and group */
+			azx_dev = get_azx_dev(substream);
+			cycle_last = azx_dev->azx_tc.cycle_last;
+
+			snd_pcm_group_for_each_entry(s, substream) {
+				if (s->pcm->card != substream->pcm->card)
+					continue;
+				azx_timecounter_init(s, 1, cycle_last);
+			}
+		}
+	}
 	spin_unlock(&chip->reg_lock);
 	return 0;
 }
@@ -2306,6 +2399,7 @@ static struct snd_pcm_ops azx_pcm_ops = {
 	.prepare = azx_pcm_prepare,
 	.trigger = azx_pcm_trigger,
 	.pointer = azx_pcm_pointer,
+	.wall_clock =  azx_get_wallclock_tstamp,
 	.mmap = azx_pcm_mmap,
 	.page = snd_pcm_sgbuf_ops_page,
 };