[PATCH] powerpc/time: When starting the decrementer don't zero the other bits in TCR

Kumar Gala galak at kernel.crashing.org
Thu Sep 1 16:27:25 EST 2011


On Aug 25, 2011, at 7:19 AM, Laurentiu Tudor wrote:

> Clearing the other TCR bits might break code that sets them (e.g. to setup
> the watchdog or fixed interval timer) before start_cpu_decrementer() gets
> called.

Can you be more specific about the case you're concerned about.  I'm not sure we want to leave the FIT enabled if it was previously.  Watchdog I could possibly see leaving alone.
> 
> Signed-off-by: Laurentiu Tudor <Laurentiu.Tudor at freescale.com>
> ---
> arch/powerpc/kernel/time.c |    2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
> index 03b29a6..e8b5cdc 100644
> --- a/arch/powerpc/kernel/time.c
> +++ b/arch/powerpc/kernel/time.c
> @@ -721,7 +721,7 @@ void start_cpu_decrementer(void)
> 	mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS);
> 
> 	/* Enable decrementer interrupt */
> -	mtspr(SPRN_TCR, TCR_DIE);
> +	mtspr(SPRN_TCR, mfspr(SPRN_TCR) | TCR_DIE);
> #endif /* defined(CONFIG_BOOKE) || defined(CONFIG_40x) */
> }
> 
> -- 
> 1.7.1
> 
> 
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