1 files changed, 33 insertions, 23 deletions

diff --git a/sound/arm/aaci.c b/sound/arm/aaci.c
index 91acc9a243ec..7c1fc64cb53d 100644
--- a/sound/arm/aaci.c
+++ b/sound/arm/aaci.c
@@ -30,6 +30,8 @@
 
 #define DRIVER_NAME     "aaci-pl041"
 
+#define FRAME_PERIOD_US 21
+
 /*
  * PM support is not complete.  Turn it off.
  */
@@ -48,7 +50,11 @@ static void aaci_ac97_select_codec(struct aaci *aaci, struct snd_ac97 *ac97)
         if (v & SLFR_1RXV)
                 readl(aaci->base + AACI_SL1RX);
 
-        writel(maincr, aaci->base + AACI_MAINCR);
+        if (maincr != readl(aaci->base + AACI_MAINCR)) {
+                writel(maincr, aaci->base + AACI_MAINCR);
+                readl(aaci->base + AACI_MAINCR);
+                udelay(1);
+        }
 }
 
 /*
@@ -64,8 +70,8 @@ static void aaci_ac97_write(struct snd_ac97 *ac97, unsigned short reg,
                             unsigned short val)
 {
         struct aaci *aaci = ac97->private_data;
+        int timeout;
         u32 v;
-        int timeout = 5000;
 
         if (ac97->num >= 4)
                 return;
@@ -81,14 +87,17 @@ static void aaci_ac97_write(struct snd_ac97 *ac97, unsigned short reg,
         writel(val << 4, aaci->base + AACI_SL2TX);
         writel(reg << 12, aaci->base + AACI_SL1TX);
 
-        /*
-         * Wait for the transmission of both slots to complete.
-         */
+        /* Initially, wait one frame period */
+        udelay(FRAME_PERIOD_US);
+
+        /* And then wait an additional eight frame periods for it to be sent */
+        timeout = FRAME_PERIOD_US * 8;
         do {
+                udelay(1);
                 v = readl(aaci->base + AACI_SLFR);
         } while ((v & (SLFR_1TXB|SLFR_2TXB)) && --timeout);
 
-        if (!timeout)
+        if (v & (SLFR_1TXB|SLFR_2TXB))
                 dev_err(&aaci->dev->dev,
                         "timeout waiting for write to complete\n");
 
@@ -101,9 +110,8 @@ static void aaci_ac97_write(struct snd_ac97 *ac97, unsigned short reg,
 static unsigned short aaci_ac97_read(struct snd_ac97 *ac97, unsigned short reg)
 {
         struct aaci *aaci = ac97->private_data;
+        int timeout, retries = 10;
         u32 v;
-        int timeout = 5000;
-        int retries = 10;
 
         if (ac97->num >= 4)
                 return ~0;
@@ -117,35 +125,34 @@ static unsigned short aaci_ac97_read(struct snd_ac97 *ac97, unsigned short reg)
          */
         writel((reg << 12) | (1 << 19), aaci->base + AACI_SL1TX);
 
-        /*
-         * Wait for the transmission to complete.
-         */
+        /* Initially, wait one frame period */
+        udelay(FRAME_PERIOD_US);
+
+        /* And then wait an additional eight frame periods for it to be sent */
+        timeout = FRAME_PERIOD_US * 8;
         do {
+                udelay(1);
                 v = readl(aaci->base + AACI_SLFR);
         } while ((v & SLFR_1TXB) && --timeout);
 
-        if (!timeout) {
+        if (v & SLFR_1TXB) {
                 dev_err(&aaci->dev->dev, "timeout on slot 1 TX busy\n");
                 v = ~0;
                 goto out;
         }
 
-        /*
-         * Give the AC'97 codec more than enough time
-         * to respond. (42us = ~2 frames at 48kHz.)
-         */
-        udelay(42);
+        /* Now wait for the response frame */
+        udelay(FRAME_PERIOD_US);
 
-        /*
-         * Wait for slot 2 to indicate data.
-         */
-        timeout = 5000;
+        /* And then wait an additional eight frame periods for data */
+        timeout = FRAME_PERIOD_US * 8;
         do {
+                udelay(1);
                 cond_resched();
                 v = readl(aaci->base + AACI_SLFR) & (SLFR_1RXV|SLFR_2RXV);
         } while ((v != (SLFR_1RXV|SLFR_2RXV)) && --timeout);
 
-        if (!timeout) {
+        if (v != (SLFR_1RXV|SLFR_2RXV)) {
                 dev_err(&aaci->dev->dev, "timeout on RX valid\n");
                 v = ~0;
                 goto out;
@@ -179,6 +186,7 @@ aaci_chan_wait_ready(struct aaci_runtime *aacirun, unsigned long mask)
         int timeout = 5000;
 
         do {
+                udelay(1);
                 val = readl(aacirun->base + AACI_SR);
         } while (val & mask && timeout--);
 }
@@ -874,7 +882,7 @@ static int __devinit aaci_probe_ac97(struct aaci *aaci)
          * Give the AC'97 codec more than enough time
          * to wake up. (42us = ~2 frames at 48kHz.)
          */
-        udelay(42);
+        udelay(FRAME_PERIOD_US * 2);
 
         ret = snd_ac97_bus(aaci->card, 0, &aaci_bus_ops, aaci, &ac97_bus);
         if (ret)
@@ -989,6 +997,8 @@ static unsigned int __devinit aaci_size_fifo(struct aaci *aaci)
          * disabling the channel doesn't clear the FIFO.
          */
         writel(aaci->maincr & ~MAINCR_IE, aaci->base + AACI_MAINCR);
+        readl(aaci->base + AACI_MAINCR);
+        udelay(1);
         writel(aaci->maincr, aaci->base + AACI_MAINCR);
 
         /*