diff options
| author | Linus Walleij <linus.walleij@linaro.org> | 2017-06-12 00:26:16 +0300 |
|---|---|---|
| committer | Daniel Lezcano <daniel.lezcano@linaro.org> | 2017-06-14 13:02:14 +0300 |
| commit | 740e237add571a125f1c2a110ba6aa77db7d2c69 (patch) | |
| tree | 17294fd61f7132e7d4e8ca90826a7318f6f600de /drivers/clocksource | |
| parent | 8b7a3b568814a8e36d2910dd74465b0215aa0a31 (diff) | |
| download | linux-740e237add571a125f1c2a110ba6aa77db7d2c69.tar.xz | |
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@linaro.org>
Cc: Andrew Jeffery <andrew@aj.id.au>
Cc: Joel Stanley <joel@jms.id.au>
Cc: Jonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Diffstat (limited to 'drivers/clocksource')
| -rw-r--r-- | drivers/clocksource/timer-fttmr010.c | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/drivers/clocksource/timer-fttmr010.c b/drivers/clocksource/timer-fttmr010.c index a21020c57df6..b56d7bdfcba1 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. |