1 files changed, 38 insertions, 29 deletions

diff --git a/sound/soc/kirkwood/kirkwood-i2s.c b/sound/soc/kirkwood/kirkwood-i2s.c
index 485af80923de..826306dfb72b 100644
--- 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: