Re: [RFC part3 PATCH 2/2] ARM64 / clocksource: Use arch_timer_acpi_init()

From: Hanjun Guo
Date: Thu Dec 05 2013 - 08:09:54 EST


On 2013å12æ04æ 23:07, Mark Rutland wrote:
On Wed, Dec 04, 2013 at 02:27:22PM +0000, Hanjun Guo wrote:
On 2013å12æ04æ 01:08, Mark Rutland wrote:
On Tue, Dec 03, 2013 at 04:41:31PM +0000, Hanjun Guo wrote:
Use arch_timer_acpi_init() on ARM64 to initialise arch timer
in ACPI way when DT is not available.

Signed-off-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
---
arch/arm64/kernel/time.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/arch/arm64/kernel/time.c b/arch/arm64/kernel/time.c
index 29c39d5..fb009da 100644
--- a/arch/arm64/kernel/time.c
+++ b/arch/arm64/kernel/time.c
@@ -67,6 +67,10 @@ void __init time_init(void)
clocksource_of_init();
+ /* if can't be initialised from DT, try ACPI way */
+ if (!arch_timer_get_rate())
+ arch_timer_acpi_init();
+
As mentioned on the previous patch, I think for the timebeing we should
rely on CNTFREQ.

Additionally, if you need to do this we should have an analagous
mechanism to clocksource_of_init() that performs this initialisation for
ACPI, and here we can call a clocksource_*_init function that does the
right thing.

There's no need for this file to know anything about ACPI.
Oh, Amit already have some patches to introduce clocksource_acpi_init()
like clocksource_of_init() did, please refer to the link below.

http://marc.info/?l=linaro-acpi&m=138131929721943&w=2

is this the idea you mentioned in your comments?
Something along those lines is far better than hardcoding
arch_timer_acpi_init here.

Thanks for the suggestion, will update it.

Hanjun
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