1 files changed, 16 insertions, 1 deletions

diff --git a/sound/soc/fsl/mpc5200_psc_ac97.c b/sound/soc/fsl/mpc5200_psc_ac97.c
index 794a247b3eb5..7eb549985d49 100644
--- a/sound/soc/fsl/mpc5200_psc_ac97.c
+++ b/sound/soc/fsl/mpc5200_psc_ac97.c
@@ -34,13 +34,20 @@ static unsigned short psc_ac97_read(struct snd_ac97 *ac97, unsigned short reg)
         int status;
         unsigned int val;
 
+        mutex_lock(&psc_dma->mutex);
+
         /* Wait for command send status zero = ready */
         status = spin_event_timeout(!(in_be16(&psc_dma->psc_regs->sr_csr.status) &
                                 MPC52xx_PSC_SR_CMDSEND), 100, 0);
         if (status == 0) {
                 pr_err("timeout on ac97 bus (rdy)\n");
+                mutex_unlock(&psc_dma->mutex);
                 return -ENODEV;
         }
+
+        /* Force clear the data valid bit */
+        in_be32(&psc_dma->psc_regs->ac97_data);
+
         /* Send the read */
         out_be32(&psc_dma->psc_regs->ac97_cmd, (1<<31) | ((reg & 0x7f) << 24));
 
@@ -50,16 +57,19 @@ static unsigned short psc_ac97_read(struct snd_ac97 *ac97, unsigned short reg)
         if (status == 0) {
                 pr_err("timeout on ac97 read (val) %x\n",
                                 in_be16(&psc_dma->psc_regs->sr_csr.status));
+                mutex_unlock(&psc_dma->mutex);
                 return -ENODEV;
         }
         /* Get the data */
         val = in_be32(&psc_dma->psc_regs->ac97_data);
         if (((val >> 24) & 0x7f) != reg) {
                 pr_err("reg echo error on ac97 read\n");
+                mutex_unlock(&psc_dma->mutex);
                 return -ENODEV;
         }
         val = (val >> 8) & 0xffff;
 
+        mutex_unlock(&psc_dma->mutex);
         return (unsigned short) val;
 }
 
@@ -68,16 +78,21 @@ static void psc_ac97_write(struct snd_ac97 *ac97,
 {
         int status;
 
+        mutex_lock(&psc_dma->mutex);
+
         /* Wait for command status zero = ready */
         status = spin_event_timeout(!(in_be16(&psc_dma->psc_regs->sr_csr.status) &
                                 MPC52xx_PSC_SR_CMDSEND), 100, 0);
         if (status == 0) {
                 pr_err("timeout on ac97 bus (write)\n");
-                return;
+                goto out;
         }
         /* Write data */
         out_be32(&psc_dma->psc_regs->ac97_cmd,
                         ((reg & 0x7f) << 24) | (val << 8));
+
+ out:
+        mutex_unlock(&psc_dma->mutex);
 }
 
 static void psc_ac97_warm_reset(struct snd_ac97 *ac97)