diff options
author | Marc Zyngier <Marc.Zyngier@arm.com> | 2011-12-15 12:19:23 +0100 |
---|---|---|
committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2011-12-18 23:00:26 +0000 |
commit | 2f0778afac79bd8d226225556858a636931eeabc (patch) | |
tree | e00cea674f3d6cc8c5584aa5b75239f11f6d229d /arch/arm/plat-orion | |
parent | 3bdc3484e8f2b1b219ad0397d81ce4601fbaf76d (diff) |
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/plat-orion')
-rw-r--r-- | arch/arm/plat-orion/time.c | 21 |
1 files changed, 3 insertions, 18 deletions
diff --git a/arch/arm/plat-orion/time.c b/arch/arm/plat-orion/time.c index 69a61367e4b..1ed8d1397fc 100644 --- a/arch/arm/plat-orion/time.c +++ b/arch/arm/plat-orion/time.c @@ -12,7 +12,6 @@ */ #include <linux/kernel.h> -#include <linux/sched.h> #include <linux/timer.h> #include <linux/clockchips.h> #include <linux/interrupt.h> @@ -60,24 +59,10 @@ static u32 ticks_per_jiffy; * Orion's sched_clock implementation. It has a resolution of * at least 7.5ns (133MHz TCLK). */ -static DEFINE_CLOCK_DATA(cd); -unsigned long long notrace sched_clock(void) +static u32 notrace orion_read_sched_clock(void) { - u32 cyc = ~readl(timer_base + TIMER0_VAL_OFF); - return cyc_to_sched_clock(&cd, cyc, (u32)~0); -} - - -static void notrace orion_update_sched_clock(void) -{ - u32 cyc = ~readl(timer_base + TIMER0_VAL_OFF); - update_sched_clock(&cd, cyc, (u32)~0); -} - -static void __init setup_sched_clock(unsigned long tclk) -{ - init_sched_clock(&cd, orion_update_sched_clock, 32, tclk); + return ~readl(timer_base + TIMER0_VAL_OFF); } /* @@ -217,7 +202,7 @@ orion_time_init(u32 _bridge_base, u32 _bridge_timer1_clr_mask, /* * Set scale and timer for sched_clock. */ - setup_sched_clock(tclk); + setup_sched_clock(orion_read_sched_clock, 32, tclk); /* * Setup free-running clocksource timer (interrupts |