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

[Jon Smirl]

On Thu, Jul 2, 2009 at 1:57 PM, Grant Likely<grant.likely at secretlab.ca> wrote:
> From: Grant Likely <grant.likely at 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 at secretlab.ca>

Acked-by: Jon Smirl <jonsmirl at 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)
>
>



-- 
Jon Smirl
jonsmirl at gmail.com