2011-05-31 08:31:21

by Mattias Wallin

Subject: [PATCH 1/3] plat-nomadik: MTU sched_clock as an option

This patch makes it possible to configure away the sched_clock
part of the MTU timer.

Signed-off-by: Mattias Wallin <[email protected]>
Acked-by: Linus Walleij <[email protected]>
---
arch/arm/plat-nomadik/Kconfig | 8 +++++++-
arch/arm/plat-nomadik/timer.c | 4 ++++
2 files changed, 11 insertions(+), 1 deletions(-)

diff --git a/arch/arm/plat-nomadik/Kconfig b/arch/arm/plat-nomadik/Kconfig
index 18296ee..d8101a4 100644
--- a/arch/arm/plat-nomadik/Kconfig
+++ b/arch/arm/plat-nomadik/Kconfig
@@ -15,12 +15,18 @@ if PLAT_NOMADIK

config HAS_MTU
bool
- select HAVE_SCHED_CLOCK
help
Support for Multi Timer Unit. MTU provides access
to multiple interrupt generating programmable
32-bit free running decrementing counters.

+config NOMADIK_MTU_SCHED_CLOCK
+ bool
+ depends on HAS_MTU
+ select HAVE_SCHED_CLOCK
+ help
+ Use the Multi Timer Unit as the sched_clock.
+
config NOMADIK_GPIO
bool
help
diff --git a/arch/arm/plat-nomadik/timer.c b/arch/arm/plat-nomadik/timer.c
index ef74e15..b55c4ec 100644
--- a/arch/arm/plat-nomadik/timer.c
+++ b/arch/arm/plat-nomadik/timer.c
@@ -25,6 +25,7 @@

void __iomem *mtu_base; /* Assigned by machine code */

+#ifdef CONFIG_NOMADIK_MTU_SCHED_CLOCK
/*
* Override the global weak sched_clock symbol with this
* local implementation which uses the clocksource to get some
@@ -48,6 +49,7 @@ static void notrace nomadik_update_sched_clock(void)
u32 cyc = -readl(mtu_base + MTU_VAL(0));
update_sched_clock(&cd, cyc, (u32)~0);
}
+#endif

/* Clockevent device: use one-shot mode */
static void nmdk_clkevt_mode(enum clock_event_mode mode,
@@ -154,7 +156,9 @@ void __init nmdk_timer_init(void)
pr_err("timer: failed to initialize clock source %s\n",
"mtu_0");

+#ifdef CONFIG_NOMADIK_MTU_SCHED_CLOCK
init_sched_clock(&cd, nomadik_update_sched_clock, 32, rate);
+#endif

/* Timer 1 is used for events */

--
1.7.4.3

2011-05-31 14:04:22

by Russell King - ARM Linux

Subject: Re: [PATCH 1/3] plat-nomadik: MTU sched_clock as an option

On Tue, May 31, 2011 at 10:30:23AM +0200, Mattias Wallin wrote:
> This patch makes it possible to configure away the sched_clock
> part of the MTU timer.

We really need better changelogs than this. Rather than saying just what
the patch is doing, please also say _why_ the change is required - you
can't expect people reading the patch to guess that kind of thing.

2011-05-31 17:03:16

by Mattias Wallin

Subject: Re: [PATCH 1/3] plat-nomadik: MTU sched_clock as an option

On 05/31/2011 04:03 PM, Russell King - ARM Linux wrote:
> On Tue, May 31, 2011 at 10:30:23AM +0200, Mattias Wallin wrote:
>> This patch makes it possible to configure away the sched_clock
>> part of the MTU timer.
>
> We really need better changelogs than this. Rather than saying just what
> the patch is doing, please also say _why_ the change is required - you
> can't expect people reading the patch to guess that kind of thing.
Thanks for the input Russell. I'll give it a new try.