[U-Boot] [PATCH] mmc: omap: timeout counter fix

[Nishanth Menon]

Menon, Nishanth had written, on 10/25/2010 06:33 PM, the following:
> Having a loop with a counter is no timing guarentee for timing
> accuracy or compiler optimizations. For e.g. the same loop counter
> which runs when the MPU is running at 600MHz will timeout in around
> half the time when running at 1GHz. or the example where GCC 4.5
> compiles with different optimization compared to GCC 4.4.
> use a udelay(10) to ensure we have a predictable delay.
> use an emperical number - 100000 uSec ~= 1sec for a worst case timeout.
> This should never happen, and is adequate imaginary condition for us
> to fail with timeout.
> 
> Signed-off-by: Nishanth Menon <nm at ti.com>
> ---
>  drivers/mmc/omap_hsmmc.c |    5 ++++-
>  1 files changed, 4 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/mmc/omap_hsmmc.c b/drivers/mmc/omap_hsmmc.c
> index 9271470..9b03ce1 100644
> --- a/drivers/mmc/omap_hsmmc.c
> +++ b/drivers/mmc/omap_hsmmc.c
> @@ -137,7 +137,7 @@ static int mmc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
>  {
>  	hsmmc_t *mmc_base = (hsmmc_t *)mmc->priv;
>  	unsigned int flags, mmc_stat;
> -	unsigned int retry = 0x100000;
> +	unsigned int retry = 100000;
>  
>  
>  	while ((readl(&mmc_base->pstate) & DATI_MASK) == DATI_CMDDIS)
> @@ -202,6 +202,9 @@ static int mmc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
>  
>  	do {
>  		mmc_stat = readl(&mmc_base->stat);
> +		if (!mmc_stat) {
> +			udelay(10);
> +		}
>  		retry--;
>  	} while ((mmc_stat == 0) && (retry > 0));
>  
I am dropping this patch instead will post a major timeout cleanup for 
omap_hsmmc.c -> caught a few other kickers as well :(.. darn the polling 
logic is so broken in the code :(

-- 
Regards,
Nishanth Menon