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authorMarc Zyngier <Marc.Zyngier@arm.com>2011-12-15 12:19:23 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2011-12-18 23:00:26 +0000
commit2f0778afac79bd8d226225556858a636931eeabc (patch)
treee00cea674f3d6cc8c5584aa5b75239f11f6d229d /arch/arm/mach-picoxcell
parent3bdc3484e8f2b1b219ad0397d81ce4601fbaf76d (diff)
downloadlinux-linaro-stable-2f0778afac79bd8d226225556858a636931eeabc.tar.gz
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-picoxcell')
-rw-r--r--arch/arm/mach-picoxcell/time.c17
1 files changed, 3 insertions, 14 deletions
diff --git a/arch/arm/mach-picoxcell/time.c b/arch/arm/mach-picoxcell/time.c
index 90a554ff4499..6c89cf8ab22e 100644
--- a/arch/arm/mach-picoxcell/time.c
+++ b/arch/arm/mach-picoxcell/time.c
@@ -11,7 +11,6 @@
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
-#include <linux/sched.h>
#include <asm/mach/time.h>
#include <asm/sched_clock.h>
@@ -66,21 +65,11 @@ static void picoxcell_add_clocksource(struct device_node *source_timer)
dw_apb_clocksource_register(cs);
}
-static DEFINE_CLOCK_DATA(cd);
static void __iomem *sched_io_base;
-unsigned long long notrace sched_clock(void)
+unsigned u32 notrace picoxcell_read_sched_clock(void)
{
- cycle_t cyc = sched_io_base ? __raw_readl(sched_io_base) : 0;
-
- return cyc_to_sched_clock(&cd, cyc, (u32)~0);
-}
-
-static void notrace picoxcell_update_sched_clock(void)
-{
- cycle_t cyc = sched_io_base ? __raw_readl(sched_io_base) : 0;
-
- update_sched_clock(&cd, cyc, (u32)~0);
+ return __raw_readl(sched_io_base);
}
static const struct of_device_id picoxcell_rtc_ids[] __initconst = {
@@ -100,7 +89,7 @@ static void picoxcell_init_sched_clock(void)
timer_get_base_and_rate(sched_timer, &sched_io_base, &rate);
of_node_put(sched_timer);
- init_sched_clock(&cd, picoxcell_update_sched_clock, 32, rate);
+ setup_sched_clock(picoxcell_read_sched_clock, 32, rate);
}
static const struct of_device_id picoxcell_timer_ids[] __initconst = {