On Sep 1, 2011, at 3:31 AM, Tudor Laurentiu wrote:
On 9/1/2011 9:27 AM, Kumar Gala wrote:
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On Aug 25, 2011, at 7:19 AM, Laurentiu Tudor wrote:
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Clearing the other TCR bits might break code that sets them (e.g. to =
setup
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the watchdog or fixed interval timer) before start_cpu_decrementer() =
gets
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called.
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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.
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My particular case was this: I was experimenting with having the =
watchdog enabled during the boot process, in case something goes wrong =
before the normal watchdog mechanism kicks in. That didn't work without =
making this modification.
Then, thinking that having a function start_cpu_decrementer() touching =
the other timers and not only the decrementer as its name implies might =
not be good. So I submitted this patch to the public mailing list to let =
the community decide if it's useful.
So I think renaming the function is fine, and I think not touching the =
watchdog bits is also reasonable. So if you update the patch along =
those lines I think we can push in. I do want to make sure that the FIT =
is disabled as we dont expect it.
Probably add a comment about how care needs to be taken if the wathchdog =
is enable be firmware or a previous kernel.
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Signed-off-by: Laurentiu Tudor<redacted>
---
arch/powerpc/kernel/time.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
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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);
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/* Enable decrementer interrupt */
- mtspr(SPRN_TCR, TCR_DIE);
+ mtspr(SPRN_TCR, mfspr(SPRN_TCR) | TCR_DIE);
#endif /* defined(CONFIG_BOOKE) || defined(CONFIG_40x) */
}
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--
1.7.1
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