[PATCH 05/10] S3C I2S: lrsync function made to work with IRQs disabled.
Ben Dooks
ben-linux at fluff.org
Tue Sep 15 20:14:39 EDT 2009
On Tue, Sep 15, 2009 at 07:02:37PM +0900, Jassi wrote:
> s3c2412_snd_lrsync() maybe reached with IRQs disabled and if LRCLK
> is dead due to improper initialization of CPU or CODEC, the system
> gets stuck in the loop because jiffies may never get updated.
> Implemented counter based wait mechanism for atleast the same
> timeout period.
>
> Signed-Off-by: Jassi <jassi.brar at samsung.com>
> ---
> sound/soc/s3c24xx/s3c-i2s-v2.c | 16 ++++++++++------
> 1 files changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/sound/soc/s3c24xx/s3c-i2s-v2.c b/sound/soc/s3c24xx/s3c-i2s-v2.c
> index aa7af0b..8865bc7 100644
> --- a/sound/soc/s3c24xx/s3c-i2s-v2.c
> +++ b/sound/soc/s3c24xx/s3c-i2s-v2.c
> @@ -230,6 +230,8 @@ static void s3c2412_snd_rxctrl(struct s3c_i2sv2_info *i2s, int on)
> pr_debug("%s: IIS: CON=%x MOD=%x FIC=%x\n", __func__, con, mod, fic);
> }
>
> +#define msecs_to_loops(t) (loops_per_jiffy / 1000 * HZ * t)
> +
> /*
> * Wait for the LR signal to allow synchronisation to the L/R clock
> * from the codec. May only be needed for slave mode.
> @@ -237,19 +239,21 @@ static void s3c2412_snd_rxctrl(struct s3c_i2sv2_info *i2s, int on)
> static int s3c2412_snd_lrsync(struct s3c_i2sv2_info *i2s)
> {
> u32 iiscon;
> - unsigned long timeout = jiffies + msecs_to_jiffies(5);
> + unsigned long loops = msecs_to_loops(5);
>
> pr_debug("Entered %s\n", __func__);
>
> - while (1) {
> + while (--loops) {
> iiscon = readl(i2s->regs + S3C2412_IISCON);
> if (iiscon & S3C2412_IISCON_LRINDEX)
> break;
>
> - if (timeout < jiffies) {
> - printk(KERN_ERR "%s: timeout\n", __func__);
> - return -ETIMEDOUT;
> - }
> + cpu_relax();
I don't think cpu_relax() gives a defined 'timeout' length, thus this
loop is of a very indeterminate length of timeout.
--
Ben
Q: What's a light-year?
A: One-third less calories than a regular year.
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