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>
diff --git a/arch/arm/plat-iop/time.c b/arch/arm/plat-iop/time.c
index 568dd02..cbfbbe4 100644
--- a/arch/arm/plat-iop/time.c
+++ b/arch/arm/plat-iop/time.c
@@ -18,7 +18,6 @@
#include <linux/time.h>
#include <linux/init.h>
#include <linux/timex.h>
-#include <linux/sched.h>
#include <linux/io.h>
#include <linux/clocksource.h>
#include <linux/clockchips.h>
@@ -52,21 +51,12 @@
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
-static DEFINE_CLOCK_DATA(cd);
-
/*
* IOP sched_clock() implementation via its clocksource.
*/
-unsigned long long notrace sched_clock(void)
+static u32 notrace iop_read_sched_clock(void)
{
- u32 cyc = 0xffffffffu - read_tcr1();
- return cyc_to_sched_clock(&cd, cyc, (u32)~0);
-}
-
-static void notrace iop_update_sched_clock(void)
-{
- u32 cyc = 0xffffffffu - read_tcr1();
- update_sched_clock(&cd, cyc, (u32)~0);
+ return 0xffffffffu - read_tcr1();
}
/*
@@ -152,7 +142,7 @@
{
u32 timer_ctl;
- init_sched_clock(&cd, iop_update_sched_clock, 32, tick_rate);
+ setup_sched_clock(iop_read_sched_clock, 32, tick_rate);
ticks_per_jiffy = DIV_ROUND_CLOSEST(tick_rate, HZ);
iop_tick_rate = tick_rate;