Hi,

Grant Likely wrote:
From: Grant Likely <grant.lik...@secretlab.ca>

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.lik...@secretlab.ca>
---

 sound/soc/fsl/mpc5200_dma.c      |    1 +
 sound/soc/fsl/mpc5200_dma.h      |    1 +
 sound/soc/fsl/mpc5200_psc_ac97.c |   13 ++++++++++++-
 3 files changed, 14 insertions(+), 1 deletions(-)


diff --git a/sound/soc/fsl/mpc5200_dma.c b/sound/soc/fsl/mpc5200_dma.c
index efec33a..f0a2d40 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 2000803..8d396bb 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 9b8503f..7eb5499 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;
maybe define an err variable and and a goto out.

Michael
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