Re: [alsa-devel] [PATCH] alsa/soc: add locking to mpc5200-psc-ac97 driver

Hi Grant,

On Mon, Jun 29, 2009 at 05:42:21PM -0600, Grant Likely wrote:

From: Grant Likely grant.likely@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.likely@secretlab.ca

sound/soc/fsl/mpc5200_dma.c | 1 + sound/soc/fsl/mpc5200_dma.h | 1 + sound/soc/fsl/mpc5200_psc_ac97.c | 17 ++++++++++++++++- 3 files changed, 18 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 794a247..7eb5499 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);

No mutex involved here. I think this is either a seperate patch or it needs at least to be mentioned in the patch description.

/* 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)

---

Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev