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authorSudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>2013-08-23 15:53:15 +0100
committerMark Brown <broonie@linaro.org>2014-05-05 16:10:04 -0700
commitd9105606cab52d214c7670e7d85834c6f699f817 (patch)
tree124e505d11fadd8c6153e83673203178a26e6881
parent5d8ac19a525254c044220fc84e50923a11c382a0 (diff)
downloadlinux-linaro-stable-v3.10/topic/evtstream.tar.gz
drivers: clocksource: add CPU PM notifier for ARM architected timerv3.10/topic/evtstream
Few control settings done in architected timer as part of initialisation can be lost when CPU enters deeper power states. They need to be restored when the CPU is (warm)reset again. This patch adds CPU PM notifiers to save the counter control register when entering low power modes and restore it when CPU exits low power. Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Reviewed-by: Will Deacon <will.deacon@arm.com> Acked-by: Olof Johansson <olof@lixom.net> Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com> (cherry picked from commit 346e7480f1d4740b3d798da60f83f087ea6488b4) Signed-off-by: Alex Shi <alex.shi@linaro.org>
-rw-r--r--drivers/clocksource/arm_arch_timer.c34
1 files changed, 34 insertions, 0 deletions
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index 9d8d0efc0f46..c5c162b76d39 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -13,6 +13,7 @@
#include <linux/device.h>
#include <linux/smp.h>
#include <linux/cpu.h>
+#include <linux/cpu_pm.h>
#include <linux/clockchips.h>
#include <linux/interrupt.h>
#include <linux/of_irq.h>
@@ -283,6 +284,33 @@ static struct notifier_block arch_timer_cpu_nb __cpuinitdata = {
.notifier_call = arch_timer_cpu_notify,
};
+#ifdef CONFIG_CPU_PM
+static unsigned int saved_cntkctl;
+static int arch_timer_cpu_pm_notify(struct notifier_block *self,
+ unsigned long action, void *hcpu)
+{
+ if (action == CPU_PM_ENTER)
+ saved_cntkctl = arch_timer_get_cntkctl();
+ else if (action == CPU_PM_ENTER_FAILED || action == CPU_PM_EXIT)
+ arch_timer_set_cntkctl(saved_cntkctl);
+ return NOTIFY_OK;
+}
+
+static struct notifier_block arch_timer_cpu_pm_notifier = {
+ .notifier_call = arch_timer_cpu_pm_notify,
+};
+
+static int __init arch_timer_cpu_pm_init(void)
+{
+ return cpu_pm_register_notifier(&arch_timer_cpu_pm_notifier);
+}
+#else
+static int __init arch_timer_cpu_pm_init(void)
+{
+ return 0;
+}
+#endif
+
static int __init arch_timer_register(void)
{
int err;
@@ -332,11 +360,17 @@ static int __init arch_timer_register(void)
if (err)
goto out_free_irq;
+ err = arch_timer_cpu_pm_init();
+ if (err)
+ goto out_unreg_notify;
+
/* Immediately configure the timer on the boot CPU */
arch_timer_setup(this_cpu_ptr(arch_timer_evt));
return 0;
+out_unreg_notify:
+ unregister_cpu_notifier(&arch_timer_cpu_nb);
out_free_irq:
if (arch_timer_use_virtual)
free_percpu_irq(arch_timer_ppi[VIRT_PPI], arch_timer_evt);