ASoC: kirkwood: implement NO_PERIOD_WAKEUP support

Permit ALSA to run without hardware interrupts from the audio interface.
Instead, ALSA will use a kernel timer to decide when to check the buffer
state, resulting in a lighter workload for the CPU.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Mark Brown <broonie@linaro.org>

2 files changed, 12 insertions, 8 deletions

diff --git a/sound/soc/kirkwood/kirkwood-dma.c b/sound/soc/kirkwood/kirkwood-dma.c
index aac22fccdcdc..4cf2245950d7 100644
--- a/sound/soc/kirkwood/kirkwood-dma.c
+++ b/sound/soc/kirkwood/kirkwood-dma.c
@@ -28,11 +28,12 @@ static struct kirkwood_dma_data *kirkwood_priv(struct snd_pcm_substream *subs)
 }
 
 static struct snd_pcm_hardware kirkwood_dma_snd_hw = {
-        .info = (SNDRV_PCM_INFO_INTERLEAVED |
-                 SNDRV_PCM_INFO_MMAP |
-                 SNDRV_PCM_INFO_MMAP_VALID |
-                 SNDRV_PCM_INFO_BLOCK_TRANSFER |
-                 SNDRV_PCM_INFO_PAUSE),
+        .info = SNDRV_PCM_INFO_INTERLEAVED |
+                SNDRV_PCM_INFO_MMAP |
+                SNDRV_PCM_INFO_MMAP_VALID |
+                SNDRV_PCM_INFO_BLOCK_TRANSFER |
+                SNDRV_PCM_INFO_PAUSE |
+                SNDRV_PCM_INFO_NO_PERIOD_WAKEUP,
         .buffer_bytes_max       = KIRKWOOD_SND_MAX_BUFFER_BYTES,
         .period_bytes_min       = KIRKWOOD_SND_MIN_PERIOD_BYTES,
         .period_bytes_max       = KIRKWOOD_SND_MAX_PERIOD_BYTES,
diff --git a/sound/soc/kirkwood/kirkwood-i2s.c b/sound/soc/kirkwood/kirkwood-i2s.c
index e98650c01eba..0704cd6d2314 100644
--- a/sound/soc/kirkwood/kirkwood-i2s.c
+++ b/sound/soc/kirkwood/kirkwood-i2s.c
@@ -234,6 +234,7 @@ static unsigned kirkwood_i2s_play_mute(unsigned ctl)
 static int kirkwood_i2s_play_trigger(struct snd_pcm_substream *substream,
                                 int cmd, struct snd_soc_dai *dai)
 {
+        struct snd_pcm_runtime *runtime = substream->runtime;
         struct kirkwood_dma_data *priv = snd_soc_dai_get_drvdata(dai);
         uint32_t ctl, value;
 
@@ -271,9 +272,11 @@ static int kirkwood_i2s_play_trigger(struct snd_pcm_substream *substream,
                 writel(value, priv->io + KIRKWOOD_PLAYCTL);
 
                 /* enable interrupts */
-                value = readl(priv->io + KIRKWOOD_INT_MASK);
-                value |= KIRKWOOD_INT_CAUSE_PLAY_BYTES;
-                writel(value, priv->io + KIRKWOOD_INT_MASK);
+                if (!runtime->no_period_wakeup) {
+                        value = readl(priv->io + KIRKWOOD_INT_MASK);
+                        value |= KIRKWOOD_INT_CAUSE_PLAY_BYTES;
+                        writel(value, priv->io + KIRKWOOD_INT_MASK);
+                }
 
                 /* enable playback */
                 writel(ctl, priv->io + KIRKWOOD_PLAYCTL);