ASOC: dwc: Improve DMA shutdown

Disabling the I2S interface with outstanding transfers prevents the
DMAC from shutting down, so keep it partially active after a stop.

Signed-off-by: Phil Elwell <phil@raspberrypi.com>

diff --git a/sound/soc/dwc/dwc-i2s.c b/sound/soc/dwc/dwc-i2s.c
index bdc8bfa..ceb7d6a 100644 (file)
--- a/sound/soc/dwc/dwc-i2s.c
+++ b/sound/soc/dwc/dwc-i2s.c
@@ -21,7 +21,7 @@
 #include <linux/reset.h>
 #include <linux/slab.h>
 #include <linux/pm_runtime.h>
-#include <sound/designware_i2s.h>
+#include <sound/designware_i2s.h> 
 #include <sound/pcm.h>
 #include <sound/pcm_params.h>
 #include <sound/soc.h>
@@ -208,15 +208,10 @@ static void i2s_start(struct dw_i2s_dev *dev,
        i2s_write_reg(dev->i2s_base, CER, 1);
 }
 
-static void i2s_stop(struct dw_i2s_dev *dev,
-               struct snd_pcm_substream *substream)
+static void i2s_pause(struct dw_i2s_dev *dev, struct snd_pcm_substream *substream)
 {
 
        i2s_clear_irqs(dev, substream->stream);
-       if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
-               i2s_write_reg(dev->i2s_base, ITER, 0);
-       else
-               i2s_write_reg(dev->i2s_base, IRER, 0);
 
        if (dev->use_pio || dev->is_jh7110)
                i2s_disable_irqs(dev, substream->stream, 8);
@@ -225,23 +220,15 @@ static void i2s_stop(struct dw_i2s_dev *dev,
 
        if (!dev->active) {
                i2s_write_reg(dev->i2s_base, CER, 0);
-               i2s_write_reg(dev->i2s_base, IER, 0);
+               /* Keep the device enabled until the shutdown - do not clear IER */
        }
 }
 
-static int dw_i2s_startup(struct snd_pcm_substream *substream,
-                         struct snd_soc_dai *cpu_dai)
+static void i2s_stop(struct dw_i2s_dev *dev, struct snd_pcm_substream *substream)
 {
-       struct dw_i2s_dev *dev = snd_soc_dai_get_drvdata(cpu_dai);
-
-       if (dev->is_jh7110) {
-               struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
-               struct snd_soc_dai_link *dai_link = rtd->dai_link;
-
-               dai_link->trigger_stop = SND_SOC_TRIGGER_ORDER_LDC;
-       }
+       i2s_clear_irqs(dev, substream->stream);
 
-       return 0;
+       i2s_disable_irqs(dev, substream->stream, 8);
 }
 
 static void dw_i2s_config(struct dw_i2s_dev *dev, int stream)
@@ -354,6 +341,62 @@ static int dw_i2s_hw_params(struct snd_pcm_substream *substream,
        return 0;
 }
 
+static int dw_i2s_startup(struct snd_pcm_substream *substream,
+                         struct snd_soc_dai *cpu_dai)
+{
+       struct dw_i2s_dev *dev = snd_soc_dai_get_drvdata(cpu_dai);
+       union dw_i2s_snd_dma_data *dma_data = NULL;
+       u32 dmacr;
+
+       dev_dbg(dev->dev, "%s(%s)\n", __func__, substream->name);
+       if (!(dev->capability & DWC_I2S_RECORD) &&
+           substream->stream == SNDRV_PCM_STREAM_CAPTURE)
+               return -EINVAL;
+
+       if (!(dev->capability & DWC_I2S_PLAY) &&
+           substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+               return -EINVAL;
+
+       dw_i2s_config(dev, substream->stream);
+       dmacr = i2s_read_reg(dev->i2s_base, I2S_DMACR);
+       if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+               dma_data = &dev->play_dma_data;
+       else if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
+               dma_data = &dev->capture_dma_data;
+
+       snd_soc_dai_set_dma_data(cpu_dai, substream, (void *)dma_data);
+       i2s_write_reg(dev->i2s_base, I2S_DMACR, dmacr);
+
+       if (dev->is_jh7110) {
+               struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
+               struct snd_soc_dai_link *dai_link = rtd->dai_link;
+
+               dai_link->trigger_stop = SND_SOC_TRIGGER_ORDER_LDC;
+       }
+
+       return 0;
+}
+
+static void dw_i2s_shutdown(struct snd_pcm_substream *substream,
+                           struct snd_soc_dai *dai)
+{
+       struct dw_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
+
+       dev_dbg(dev->dev, "%s(%s)\n", __func__, substream->name);
+       i2s_disable_channels(dev, substream->stream);
+       if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+               i2s_write_reg(dev->i2s_base, ITER, 0);
+       else
+               i2s_write_reg(dev->i2s_base, IRER, 0);
+
+       i2s_disable_irqs(dev, substream->stream, 8);
+
+       if (!dev->active) {
+               i2s_write_reg(dev->i2s_base, CER, 0);
+               i2s_write_reg(dev->i2s_base, IER, 0);
+       }
+}
+
 static int dw_i2s_prepare(struct snd_pcm_substream *substream,
                          struct snd_soc_dai *dai)
 {
@@ -381,9 +424,12 @@ static int dw_i2s_trigger(struct snd_pcm_substream *substream,
                i2s_start(dev, substream);
                break;
 
+       case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+               dev->active--;
+               i2s_pause(dev, substream);
+               break;
        case SNDRV_PCM_TRIGGER_STOP:
        case SNDRV_PCM_TRIGGER_SUSPEND:
-       case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
                dev->active--;
                i2s_stop(dev, substream);
                break;
@@ -512,6 +558,7 @@ static int dw_i2s_dai_probe(struct snd_soc_dai *dai)
 static const struct snd_soc_dai_ops dw_i2s_dai_ops = {
        .probe          = dw_i2s_dai_probe,
        .startup        = dw_i2s_startup,
+       .shutdown       = dw_i2s_shutdown,
        .hw_params      = dw_i2s_hw_params,
        .prepare        = dw_i2s_prepare,
        .trigger        = dw_i2s_trigger,