[U-Boot] [PATCH] OMAP[34]: fix broken timer

[Igor Grinberg <grinberg@compulab.co.il>]

Sandeep, Albert,


Please, apply this patch. It fixes a real issue with timer on omap.


Thanks


On 12/28/10 02:33, John Rigby wrote:

> As implemented now the timer used to implement __udelay counts
> to 0xffffffff and then gets stuck there because the the programmed
> reload value is 0xffffffff.  This value is not only wrong but
> illegal according to the reference manual.
>
> One can reproduce the bug by leaving a board at the u-boot prompt
> for sometime then issuing a sleep command.  The sleep will hang
> forever.
>
> The timer is a count up timer that reloads as it rolls over
> from 0xffffffff so the correct load value is 0.
>
> Change TIMER_LOAD_VAL from 0xffffffff to 0 and introduce
> a new constant called TIMER_OVERFLOW_VAL set to 0xffffffff.
>
> Signed-off-by: John Rigby <john.rigby@linaro.org>

Tested-by: Igor Grinberg <grinberg@compulab.co.il>

On DM3730, AM3703, OMAP3530.

> ---
>  arch/arm/cpu/armv7/omap-common/timer.c |    7 ++++---
>  1 files changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm/cpu/armv7/omap-common/timer.c b/arch/arm/cpu/armv7/omap-common/timer.c
> index 9beebb1..59bbca8 100644
> --- a/arch/arm/cpu/armv7/omap-common/timer.c
> +++ b/arch/arm/cpu/armv7/omap-common/timer.c
> @@ -43,8 +43,9 @@ static struct gptimer *timer_base = (struct gptimer *)CONFIG_SYS_TIMERBASE;
>   * Nothing really to do with interrupts, just starts up a counter.
>   */
>  
> -#define TIMER_CLOCK	(V_SCLK / (2 << CONFIG_SYS_PTV))
> -#define TIMER_LOAD_VAL	0xffffffff
> +#define TIMER_CLOCK		(V_SCLK / (2 << CONFIG_SYS_PTV))
> +#define TIMER_OVERFLOW_VAL	0xffffffff
> +#define TIMER_LOAD_VAL		0
>  
>  int timer_init(void)
>  {
> @@ -86,7 +87,7 @@ void __udelay(unsigned long usec)
>  	while (tmo > 0) {
>  		now = readl(&timer_base->tcrr);
>  		if (last > now) /* count up timer overflow */
> -			tmo -= TIMER_LOAD_VAL - last + now;
> +			tmo -= TIMER_OVERFLOW_VAL - last + now + 1;
>  		else
>  			tmo -= now - last;
>  		last = now;

-- 
Regards,
Igor.