ASoC: kirkwood-i2s: fix DMA underruns

[platform/adaptation/renesas_rcar/renesas_kernel.git] / sound / soc / kirkwood / kirkwood-i2s.c

diff --git a/sound/soc/kirkwood/kirkwood-i2s.c b/sound/soc/kirkwood/kirkwood-i2s.c
index 485af80..826306d 100644 (file)
--- a/sound/soc/kirkwood/kirkwood-i2s.c
+++ b/sound/soc/kirkwood/kirkwood-i2s.c
@@ -180,67 +180,76 @@ static int kirkwood_i2s_play_trigger(struct snd_pcm_substream *substream,
                                int cmd, struct snd_soc_dai *dai)
 {
        struct kirkwood_dma_data *priv = snd_soc_dai_get_drvdata(dai);
-       unsigned long value;
-
-       /*
-        * specs says KIRKWOOD_PLAYCTL must be read 2 times before
-        * changing it. So read 1 time here and 1 later.
-        */
-       value = readl(priv->io + KIRKWOOD_PLAYCTL);
+       uint32_t ctl, value;
+
+       ctl = readl(priv->io + KIRKWOOD_PLAYCTL);
+       if (ctl & KIRKWOOD_PLAYCTL_PAUSE) {
+               unsigned timeout = 5000;
+               /*
+                * The Armada510 spec says that if we enter pause mode, the
+                * busy bit must be read back as clear _twice_.  Make sure
+                * we respect that otherwise we get DMA underruns.
+                */
+               do {
+                       value = ctl;
+                       ctl = readl(priv->io + KIRKWOOD_PLAYCTL);
+                       if (!((ctl | value) & KIRKWOOD_PLAYCTL_PLAY_BUSY))
+                               break;
+                       udelay(1);
+               } while (timeout--);
+
+               if ((ctl | value) & KIRKWOOD_PLAYCTL_PLAY_BUSY)
+                       dev_notice(dai->dev, "timed out waiting for busy to deassert: %08x\n",
+                                  ctl);
+       }
 
        switch (cmd) {
        case SNDRV_PCM_TRIGGER_START:
                /* stop audio, enable interrupts */
-               value = readl(priv->io + KIRKWOOD_PLAYCTL);
-               value |= KIRKWOOD_PLAYCTL_PAUSE;
-               writel(value, priv->io + KIRKWOOD_PLAYCTL);
+               ctl |= KIRKWOOD_PLAYCTL_PAUSE;
+               writel(ctl, priv->io + KIRKWOOD_PLAYCTL);
 
                value = readl(priv->io + KIRKWOOD_INT_MASK);
                value |= KIRKWOOD_INT_CAUSE_PLAY_BYTES;
                writel(value, priv->io + KIRKWOOD_INT_MASK);
 
                /* configure audio & enable i2s playback */
-               value = readl(priv->io + KIRKWOOD_PLAYCTL);
-               value &= ~KIRKWOOD_PLAYCTL_BURST_MASK;
-               value &= ~(KIRKWOOD_PLAYCTL_PAUSE | KIRKWOOD_PLAYCTL_I2S_MUTE
+               ctl &= ~KIRKWOOD_PLAYCTL_BURST_MASK;
+               ctl &= ~(KIRKWOOD_PLAYCTL_PAUSE | KIRKWOOD_PLAYCTL_I2S_MUTE
                                | KIRKWOOD_PLAYCTL_SPDIF_EN);
 
                if (priv->burst == 32)
-                       value |= KIRKWOOD_PLAYCTL_BURST_32;
+                       ctl |= KIRKWOOD_PLAYCTL_BURST_32;
                else
-                       value |= KIRKWOOD_PLAYCTL_BURST_128;
-               value |= KIRKWOOD_PLAYCTL_I2S_EN;
-               writel(value, priv->io + KIRKWOOD_PLAYCTL);
+                       ctl |= KIRKWOOD_PLAYCTL_BURST_128;
+               ctl |= KIRKWOOD_PLAYCTL_I2S_EN;
+               writel(ctl, priv->io + KIRKWOOD_PLAYCTL);
                break;
 
        case SNDRV_PCM_TRIGGER_STOP:
                /* stop audio, disable interrupts */
-               value = readl(priv->io + KIRKWOOD_PLAYCTL);
-               value |= KIRKWOOD_PLAYCTL_PAUSE | KIRKWOOD_PLAYCTL_I2S_MUTE;
-               writel(value, priv->io + KIRKWOOD_PLAYCTL);
+               ctl |= KIRKWOOD_PLAYCTL_PAUSE | KIRKWOOD_PLAYCTL_I2S_MUTE;
+               writel(ctl, priv->io + KIRKWOOD_PLAYCTL);
 
                value = readl(priv->io + KIRKWOOD_INT_MASK);
                value &= ~KIRKWOOD_INT_CAUSE_PLAY_BYTES;
                writel(value, priv->io + KIRKWOOD_INT_MASK);
 
                /* disable all playbacks */
-               value = readl(priv->io + KIRKWOOD_PLAYCTL);
-               value &= ~(KIRKWOOD_PLAYCTL_I2S_EN | KIRKWOOD_PLAYCTL_SPDIF_EN);
-               writel(value, priv->io + KIRKWOOD_PLAYCTL);
+               ctl &= ~(KIRKWOOD_PLAYCTL_I2S_EN | KIRKWOOD_PLAYCTL_SPDIF_EN);
+               writel(ctl, priv->io + KIRKWOOD_PLAYCTL);
                break;
 
        case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
        case SNDRV_PCM_TRIGGER_SUSPEND:
-               value = readl(priv->io + KIRKWOOD_PLAYCTL);
-               value |= KIRKWOOD_PLAYCTL_PAUSE | KIRKWOOD_PLAYCTL_I2S_MUTE;
-               writel(value, priv->io + KIRKWOOD_PLAYCTL);
+               ctl |= KIRKWOOD_PLAYCTL_PAUSE | KIRKWOOD_PLAYCTL_I2S_MUTE;
+               writel(ctl, priv->io + KIRKWOOD_PLAYCTL);
                break;
 
        case SNDRV_PCM_TRIGGER_RESUME:
        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
-               value = readl(priv->io + KIRKWOOD_PLAYCTL);
-               value &= ~(KIRKWOOD_PLAYCTL_PAUSE | KIRKWOOD_PLAYCTL_I2S_MUTE);
-               writel(value, priv->io + KIRKWOOD_PLAYCTL);
+               ctl &= ~(KIRKWOOD_PLAYCTL_PAUSE | KIRKWOOD_PLAYCTL_I2S_MUTE);
+               writel(ctl, priv->io + KIRKWOOD_PLAYCTL);
                break;
 
        default: