From 2f0778afac79bd8d226225556858a636931eeabc Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Thu, 15 Dec 2011 12:19:23 +0100 Subject: 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 Cc: Eric Miao Cc: Colin Cross Cc: Erik Gilling Cc: Olof Johansson Cc: Sascha Hauer Cc: Alessandro Rubini Cc: STEricsson Cc: Lennert Buytenhek Cc: Ben Dooks Tested-by: Jamie Iles Tested-by: Tony Lindgren Tested-by: Kyungmin Park Acked-by: Linus Walleij Acked-by: Nicolas Pitre Acked-by: Krzysztof Halasa Acked-by: Kukjin Kim Signed-off-by: Marc Zyngier Signed-off-by: Russell King --- arch/arm/plat-s5p/s5p-time.c | 19 +++---------------- 1 file changed, 3 insertions(+), 16 deletions(-) (limited to 'arch/arm/plat-s5p/s5p-time.c') diff --git a/arch/arm/plat-s5p/s5p-time.c b/arch/arm/plat-s5p/s5p-time.c index c833e7b5759..17c0a2c58df 100644 --- a/arch/arm/plat-s5p/s5p-time.c +++ b/arch/arm/plat-s5p/s5p-time.c @@ -10,7 +10,6 @@ * published by the Free Software Foundation. */ -#include #include #include #include @@ -321,26 +320,14 @@ static void __iomem *s5p_timer_reg(void) * this wraps around for now, since it is just a relative time * stamp. (Inspired by U300 implementation.) */ -static DEFINE_CLOCK_DATA(cd); - -unsigned long long notrace sched_clock(void) +static u32 notrace s5p_read_sched_clock(void) { void __iomem *reg = s5p_timer_reg(); if (!reg) return 0; - return cyc_to_sched_clock(&cd, ~__raw_readl(reg), (u32)~0); -} - -static void notrace s5p_update_sched_clock(void) -{ - void __iomem *reg = s5p_timer_reg(); - - if (!reg) - return; - - update_sched_clock(&cd, ~__raw_readl(reg), (u32)~0); + return ~__raw_readl(reg); } static void __init s5p_clocksource_init(void) @@ -358,7 +345,7 @@ static void __init s5p_clocksource_init(void) s5p_time_setup(timer_source.source_id, TCNT_MAX); s5p_time_start(timer_source.source_id, PERIODIC); - init_sched_clock(&cd, s5p_update_sched_clock, 32, clock_rate); + setup_sched_clock(s5p_read_sched_clock, 32, clock_rate); if (clocksource_mmio_init(s5p_timer_reg(), "s5p_clocksource_timer", clock_rate, 250, 32, clocksource_mmio_readl_down)) -- cgit v1.2.3-70-g09d2