diff options
author | Marc Zyngier <Marc.Zyngier@arm.com> | 2011-12-15 11:19:23 (GMT) |
---|---|---|
committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2011-12-18 23:00:26 (GMT) |
commit | 2f0778afac79bd8d226225556858a636931eeabc (patch) | |
tree | e00cea674f3d6cc8c5584aa5b75239f11f6d229d /arch/arm/mach-omap1/time.c | |
parent | 3bdc3484e8f2b1b219ad0397d81ce4601fbaf76d (diff) | |
download | linux-2f0778afac79bd8d226225556858a636931eeabc.tar.xz |
ARM: 7205/2: sched_clock: allow sched_clock to be selected at runtime
sched_clock() is yet another blocker on the road to the single
image. This patch implements an idea by Russell King:
http://www.spinics.net/lists/linux-omap/msg49561.html
Instead of asking the platform to implement both sched_clock()
itself and the rollover callback, simply register a read()
function, and let the ARM code care about sched_clock() itself,
the conversion to ns and the rollover. sched_clock() uses
this read() function as an indirection to the platform code.
If the platform doesn't provide a read(), the code falls back
to the jiffy counter (just like the default sched_clock).
This allow some simplifications and possibly some footprint gain
when multiple platforms are compiled in. Among the drawbacks,
the removal of the *_fixed_sched_clock optimization which could
negatively impact some platforms (sa1100, tegra, versatile
and omap).
Tested on 11MPCore, OMAP4 and Tegra.
Cc: Imre Kaloz <kaloz@openwrt.org>
Cc: Eric Miao <eric.y.miao@gmail.com>
Cc: Colin Cross <ccross@android.com>
Cc: Erik Gilling <konkers@android.com>
Cc: Olof Johansson <olof@lixom.net>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: Alessandro Rubini <rubini@unipv.it>
Cc: STEricsson <STEricsson_nomadik_linux@list.st.com>
Cc: Lennert Buytenhek <kernel@wantstofly.org>
Cc: Ben Dooks <ben-linux@fluff.org>
Tested-by: Jamie Iles <jamie@jamieiles.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Krzysztof Halasa <khc@pm.waw.pl>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/mach-omap1/time.c')
-rw-r--r-- | arch/arm/mach-omap1/time.c | 58 |
1 files changed, 4 insertions, 54 deletions
diff --git a/arch/arm/mach-omap1/time.c b/arch/arm/mach-omap1/time.c index 485a21d..b8faffa 100644 --- a/arch/arm/mach-omap1/time.c +++ b/arch/arm/mach-omap1/time.c @@ -37,7 +37,6 @@ #include <linux/init.h> #include <linux/delay.h> #include <linux/interrupt.h> -#include <linux/sched.h> #include <linux/spinlock.h> #include <linux/clk.h> #include <linux/err.h> @@ -190,30 +189,9 @@ static __init void omap_init_mpu_timer(unsigned long rate) * --------------------------------------------------------------------------- */ -static DEFINE_CLOCK_DATA(cd); - -static inline unsigned long long notrace _omap_mpu_sched_clock(void) -{ - u32 cyc = ~omap_mpu_timer_read(1); - return cyc_to_sched_clock(&cd, cyc, (u32)~0); -} - -#ifndef CONFIG_OMAP_32K_TIMER -unsigned long long notrace sched_clock(void) -{ - return _omap_mpu_sched_clock(); -} -#else -static unsigned long long notrace omap_mpu_sched_clock(void) -{ - return _omap_mpu_sched_clock(); -} -#endif - -static void notrace mpu_update_sched_clock(void) +static u32 notrace omap_mpu_read_sched_clock(void) { - u32 cyc = ~omap_mpu_timer_read(1); - update_sched_clock(&cd, cyc, (u32)~0); + return ~omap_mpu_timer_read(1); } static void __init omap_init_clocksource(unsigned long rate) @@ -223,7 +201,7 @@ static void __init omap_init_clocksource(unsigned long rate) "%s: can't register clocksource!\n"; omap_mpu_timer_start(1, ~0, 1); - init_sched_clock(&cd, mpu_update_sched_clock, 32, rate); + setup_sched_clock(omap_mpu_read_sched_clock, 32, rate); if (clocksource_mmio_init(&timer->read_tim, "mpu_timer2", rate, 300, 32, clocksource_mmio_readl_down)) @@ -254,30 +232,6 @@ static inline void omap_mpu_timer_init(void) } #endif /* CONFIG_OMAP_MPU_TIMER */ -#if defined(CONFIG_OMAP_MPU_TIMER) && defined(CONFIG_OMAP_32K_TIMER) -static unsigned long long (*preferred_sched_clock)(void); - -unsigned long long notrace sched_clock(void) -{ - if (!preferred_sched_clock) - return 0; - - return preferred_sched_clock(); -} - -static inline void preferred_sched_clock_init(bool use_32k_sched_clock) -{ - if (use_32k_sched_clock) - preferred_sched_clock = omap_32k_sched_clock; - else - preferred_sched_clock = omap_mpu_sched_clock; -} -#else -static inline void preferred_sched_clock_init(bool use_32k_sched_clcok) -{ -} -#endif - static inline int omap_32k_timer_usable(void) { int res = false; @@ -299,12 +253,8 @@ static inline int omap_32k_timer_usable(void) */ static void __init omap1_timer_init(void) { - if (omap_32k_timer_usable()) { - preferred_sched_clock_init(1); - } else { + if (!omap_32k_timer_usable()) omap_mpu_timer_init(); - preferred_sched_clock_init(0); - } } struct sys_timer omap1_timer = { |