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 <arnd@xxxxxxxx> Cc: John Stultz <john.stultz@xxxxxxxxxx> Cc: Felipe Balbi <balbi@xxxxxx> Cc: Tony Lindgren <tony@xxxxxxxxxxx> Cc: Marc Zyngier <marc.zyngier@xxxxxxx> Reviewed-by: Santosh Shilimkar <ssantosh@xxxxxxxxxx> Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx> --- Changes in v4: - check current timer's state before enabling. Changes in v3: - dropped all DT specific code Changes in v2: - suspend/resume simplified: nothing is stored any more and ARM GT just re-enabled Links on prev versions: v3: https://lkml.org/lkml/2015/11/27/402 v2: https://lkml.org/lkml/2015/11/20/355 v1: https://lkml.org/lkml/2015/11/13/456 drivers/clocksource/arm_global_timer.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/clocksource/arm_global_timer.c b/drivers/clocksource/arm_global_timer.c index a2cb6fa..817a787 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 -- 2.6.3 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
