From 08e4b44852626f3549c8bd45308431d9c9e0ee6d Mon Sep 17 00:00:00 2001 From: Jisheng Zhang Date: Thu, 26 Nov 2015 20:20:38 +0800 Subject: clockevents/drivers/arm_global_timer: Use writel_relaxed in gt_compare_set Use the relaxed version to improve performance. we measured time of 4096 rounds of gt_compare_set() spent on Marvell BG2Q: before the patch: 3690648ns on average after the patch: 1083023ns on average improved by 70%! Signed-off-by: Jisheng Zhang Signed-off-by: Daniel Lezcano --- drivers/clocksource/arm_global_timer.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'drivers/clocksource/arm_global_timer.c') diff --git a/drivers/clocksource/arm_global_timer.c b/drivers/clocksource/arm_global_timer.c index a2cb6fae9295..f99be6bafad1 100644 --- a/drivers/clocksource/arm_global_timer.c +++ b/drivers/clocksource/arm_global_timer.c @@ -99,17 +99,17 @@ static void gt_compare_set(unsigned long delta, int periodic) counter += delta; ctrl = GT_CONTROL_TIMER_ENABLE; - writel(ctrl, gt_base + GT_CONTROL); - writel(lower_32_bits(counter), gt_base + GT_COMP0); - writel(upper_32_bits(counter), gt_base + GT_COMP1); + writel_relaxed(ctrl, gt_base + GT_CONTROL); + writel_relaxed(lower_32_bits(counter), gt_base + GT_COMP0); + writel_relaxed(upper_32_bits(counter), gt_base + GT_COMP1); if (periodic) { - writel(delta, gt_base + GT_AUTO_INC); + writel_relaxed(delta, gt_base + GT_AUTO_INC); ctrl |= GT_CONTROL_AUTO_INC; } ctrl |= GT_CONTROL_COMP_ENABLE | GT_CONTROL_IRQ_ENABLE; - writel(ctrl, gt_base + GT_CONTROL); + writel_relaxed(ctrl, gt_base + GT_CONTROL); } static int gt_clockevent_shutdown(struct clock_event_device *evt) -- cgit v1.2.3 From 9c9ae5ffee2831c0b8c0b002443b093e141d08f1 Mon Sep 17 00:00:00 2001 From: Grygorii Strashko Date: Mon, 30 Nov 2015 20:25:12 +0200 Subject: clocksource/drivers/arm_global_timer: Fix suspend resume Now the System stall is observed on TI AM437x based board (am437x-gp-evm) during resuming from System suspend when ARM Global timer is selected as clocksource device (CPUIdle not enabled) - SysRq are working, but nothing else. The reason of stall is that ARM Global timer loses its contexts during System suspend: GT_CONTROL.TIMER_ENABLE = 0 (unbanked) GT_COUNTERx = 0 Hence, update ARM Global timer driver to reflect above behaviour - re-enable ARM Global timer on resume (GT_CONTROL.TIMER_ENABLE = 1) if not enabled. CC: Arnd Bergmann Cc: John Stultz Cc: Felipe Balbi Cc: Tony Lindgren Cc: Marc Zyngier Reviewed-by: Santosh Shilimkar Signed-off-by: Grygorii Strashko Signed-off-by: Daniel Lezcano --- drivers/clocksource/arm_global_timer.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'drivers/clocksource/arm_global_timer.c') diff --git a/drivers/clocksource/arm_global_timer.c b/drivers/clocksource/arm_global_timer.c index f99be6bafad1..d189d8cb69f7 100644 --- a/drivers/clocksource/arm_global_timer.c +++ b/drivers/clocksource/arm_global_timer.c @@ -195,12 +195,23 @@ static cycle_t gt_clocksource_read(struct clocksource *cs) return gt_counter_read(); } +static void gt_resume(struct clocksource *cs) +{ + unsigned long ctrl; + + ctrl = readl(gt_base + GT_CONTROL); + if (!(ctrl & GT_CONTROL_TIMER_ENABLE)) + /* re-enable timer on resume */ + writel(GT_CONTROL_TIMER_ENABLE, gt_base + GT_CONTROL); +} + static struct clocksource gt_clocksource = { .name = "arm_global_timer", .rating = 300, .read = gt_clocksource_read, .mask = CLOCKSOURCE_MASK(64), .flags = CLOCK_SOURCE_IS_CONTINUOUS, + .resume = gt_resume, }; #ifdef CONFIG_CLKSRC_ARM_GLOBAL_TIMER_SCHED_CLOCK -- cgit v1.2.3