ASoC: add locking to mpc5200-psc-ac97 driver

AC97 bus register read/write hooks need to provide locking, but the
mpc5200-psc-ac97 driver does not.  This patch adds a mutex around
the register access routines.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Jon Smirl <jonsmirl@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

3 files changed, 14 insertions, 1 deletions

diff --git a/sound/soc/fsl/mpc5200_dma.c b/sound/soc/fsl/mpc5200_dma.c
index efec33a1c5bd..f0a2d4071998 100644
--- a/sound/soc/fsl/mpc5200_dma.c
+++ b/sound/soc/fsl/mpc5200_dma.c
@@ -456,6 +456,7 @@ int mpc5200_audio_dma_create(struct of_device *op)
                 return -ENODEV;
 
         spin_lock_init(&psc_dma->lock);
+        mutex_init(&psc_dma->mutex);
         psc_dma->id = be32_to_cpu(*prop);
         psc_dma->irq = irq;
         psc_dma->psc_regs = regs;
diff --git a/sound/soc/fsl/mpc5200_dma.h b/sound/soc/fsl/mpc5200_dma.h
index 2000803f06a7..8d396bb9d9fe 100644
--- a/sound/soc/fsl/mpc5200_dma.h
+++ b/sound/soc/fsl/mpc5200_dma.h
@@ -55,6 +55,7 @@ struct psc_dma {
         unsigned int irq;
         struct device *dev;
         spinlock_t lock;
+        struct mutex mutex;
         u32 sicr;
         uint sysclk;
         int imr;
diff --git a/sound/soc/fsl/mpc5200_psc_ac97.c b/sound/soc/fsl/mpc5200_psc_ac97.c
index 9b8503f2d68c..7eb549985d49 100644
--- a/sound/soc/fsl/mpc5200_psc_ac97.c
+++ b/sound/soc/fsl/mpc5200_psc_ac97.c
@@ -34,11 +34,14 @@ 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;
         }
 
@@ -54,16 +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;
 }
 
@@ -72,16 +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)