Commit-ID: 740e237add571a125f1c2a110ba6aa77db7d2c69
Gitweb: http://git.kernel.org/tip/740e237add571a125f1c2a110ba6aa77db7d2c69
Author: Linus Walleij <linus.walleij@xxxxxxxxxx>
AuthorDate: Sun, 11 Jun 2017 23:26:16 +0200
Committer: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
CommitDate: Wed, 14 Jun 2017 12:02:14 +0200
clocksource/drivers/fttmr010: Optimize sched_clock()
The sched_clock() call should be really fast so we want to
avoid an extra if() clause on the read path if possible.
Implement two sched_clock_read() functions, one if the timer
counts up and one if it counts down. Incidentally this also
mirrors how clocksource_mmio_init() works and make things
simple and easy to understand.
Suggested-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
Cc: Andrew Jeffery <andrew@xxxxxxxx>
Cc: Joel Stanley <joel@xxxxxxxxx>
Cc: Jonas Jensen <jonas.jensen@xxxxxxxxx>
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
---
drivers/clocksource/timer-fttmr010.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/drivers/clocksource/timer-fttmr010.c b/drivers/clocksource/timer-fttmr010.c
index a21020c..b56d7bd 100644
--- a/drivers/clocksource/timer-fttmr010.c
+++ b/drivers/clocksource/timer-fttmr010.c
@@ -91,13 +91,16 @@ static inline struct fttmr010 *to_fttmr010(struct clock_event_device *evt)
return container_of(evt, struct fttmr010, clkevt);
}
-static u64 notrace fttmr010_read_sched_clock(void)
+static u64 notrace fttmr010_read_sched_clock_up(void)
{
- if (local_fttmr->count_down)
- return ~readl(local_fttmr->base + TIMER2_COUNT);
return readl(local_fttmr->base + TIMER2_COUNT);
}
+static u64 notrace fttmr010_read_sched_clock_down(void)
+{
+ return ~readl(local_fttmr->base + TIMER2_COUNT);
+}
+
static int fttmr010_timer_set_next_event(unsigned long cycles,
struct clock_event_device *evt)
{
@@ -302,15 +305,17 @@ static int __init fttmr010_common_init(struct device_node *np, bool is_aspeed)
"FTTMR010-TIMER2",
fttmr010->tick_rate,
300, 32, clocksource_mmio_readl_down);
+ sched_clock_register(fttmr010_read_sched_clock_down, 32,
+ fttmr010->tick_rate);
} else {
writel(0, fttmr010->base + TIMER2_LOAD);
clocksource_mmio_init(fttmr010->base + TIMER2_COUNT,
"FTTMR010-TIMER2",
fttmr010->tick_rate,
300, 32, clocksource_mmio_readl_up);
+ sched_clock_register(fttmr010_read_sched_clock_up, 32,
+ fttmr010->tick_rate);
}
- sched_clock_register(fttmr010_read_sched_clock, 32,
- fttmr010->tick_rate);
/*
* Setup clockevent timer (interrupt-driven) on timer 1.
--
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