Re: [alsa-devel] [PATCH 2/2] ASoC: add locking to mpc5200-psc-ac97 driver

On Thu, Jul 2, 2009 at 1:57 PM, Grant Likelygrant.likely@secretlab.ca 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

Acked-by: Jon Smirl jonsmirl@gmail.com

---

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;        }

@@ -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)