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From: tony@atomide.com (Tony Lindgren)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] omap: timer: Set dmtimer used as clocksource in autoreload mode
Date: Wed, 10 Aug 2011 04:51:22 -0700	[thread overview]
Message-ID: <20110810115122.GH1939@atomide.com> (raw)
In-Reply-To: <1312948323-22823-1-git-send-email-hemantp@ti.com>

* Hemant Pedanekar <hemantp@ti.com> [110809 20:46]:
> If CONFIG_OMAP_32K_TIMER is not selected and dmtimer is used as clocksource, the
> timer stops counting once overflow occurs as it was not set in autoreload mode.
> This results into timekeeping failure: for example, 'sleep 1' at the shell after
> the timer counter overflow would hang.
> 
> This patch sets up autoreload when starting the clocksource timer which fixes
> the above issue.
> 
> Signed-off-by: Hemant Pedanekar <hemantp@ti.com>
> ---
>  arch/arm/mach-omap2/timer.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
> index e964072..796b935 100644
> --- a/arch/arm/mach-omap2/timer.c
> +++ b/arch/arm/mach-omap2/timer.c
> @@ -293,7 +293,7 @@ static void __init omap2_gp_clocksource_init(int gptimer_id,
>  	pr_info("OMAP clocksource: GPTIMER%d at %lu Hz\n",
>  		gptimer_id, clksrc.rate);
>  
> -	__omap_dm_timer_load_start(clksrc.io_base, OMAP_TIMER_CTRL_ST, 0, 1);
> +	omap_dm_timer_set_load_start(&clksrc, 1, 0);
>  	init_sched_clock(&cd, dmtimer_update_sched_clock, 32, clksrc.rate);
>  
>  	if (clocksource_register_hz(&clocksource_gpt, clksrc.rate))

You should be able to just set the autoreload mode by changing to use
OMAP_TIMER_CTRL_POSTED | OMAP_TIMER_CTRL_AR in the __omap_dm_timer_load_start
above.

This avoids calling something that might be a loadable module eventually.

Regards,

Tony

  reply	other threads:[~2011-08-10 11:51 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-08-10  3:52 [PATCH] omap: timer: Set dmtimer used as clocksource in autoreload mode Hemant Pedanekar
2011-08-10 11:51 ` Tony Lindgren [this message]
2011-08-10 12:25   ` Pedanekar, Hemant

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