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

From: michael <[email-masked]>
Date: Thu, 02 Jul 2009 21:08:27 +0200

Hi,

Grant Likely wrote:
> From: Grant Likely <[email-masked]>
>
> 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 <[email-masked]>
> ---
>
>  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