ARM: OMAP2+: Add functions to save and restore powerdomain context

The powerdomain control registers are stored in the WKUP powerdomain on
AM33XX/AM43XX, which is lost on RTC-only suspend and also hibernate. This
adds context save and restore functions for those registers.
Sometimes the powerdomain state does not need to change,
perhaps we only need to change memory retention states, so make
sure the restored state is different from the current state before we wait
for a transition.

Signed-off-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
Signed-off-by: Russ Dill <Russ.Dill@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

1 files changed, 60 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/powerdomain.c b/arch/arm/mach-omap2/powerdomain.c
index 76eb6ec5f157..ee693f679ae8 100644
--- a/arch/arm/mach-omap2/powerdomain.c
+++ b/arch/arm/mach-omap2/powerdomain.c
@@ -1199,3 +1199,63 @@ bool pwrdm_can_ever_lose_context(struct powerdomain *pwrdm)
 
 	return 0;
 }
+
+/**
+ * pwrdm_save_context - save powerdomain registers
+ *
+ * Register state is going to be lost due to a suspend or hibernate
+ * event. Save the powerdomain registers.
+ */
+static int pwrdm_save_context(struct powerdomain *pwrdm, void *unused)
+{
+	if (arch_pwrdm && arch_pwrdm->pwrdm_save_context)
+		arch_pwrdm->pwrdm_save_context(pwrdm);
+	return 0;
+}
+
+/**
+ * pwrdm_save_context - restore powerdomain registers
+ *
+ * Restore powerdomain control registers after a suspend or resume
+ * event.
+ */
+static int pwrdm_restore_context(struct powerdomain *pwrdm, void *unused)
+{
+	if (arch_pwrdm && arch_pwrdm->pwrdm_restore_context)
+		arch_pwrdm->pwrdm_restore_context(pwrdm);
+	return 0;
+}
+
+static int pwrdm_lost_power(struct powerdomain *pwrdm, void *unused)
+{
+	int state;
+
+	/*
+	 * Power has been lost across all powerdomains, increment the
+	 * counter.
+	 */
+
+	state = pwrdm_read_pwrst(pwrdm);
+	if (state != PWRDM_POWER_OFF) {
+		pwrdm->state_counter[state]++;
+		pwrdm->state_counter[PWRDM_POWER_OFF]++;
+	}
+	pwrdm->state = state;
+
+	return 0;
+}
+
+void pwrdms_save_context(void)
+{
+	pwrdm_for_each(pwrdm_save_context, NULL);
+}
+
+void pwrdms_restore_context(void)
+{
+	pwrdm_for_each(pwrdm_restore_context, NULL);
+}
+
+void pwrdms_lost_power(void)
+{
+	pwrdm_for_each(pwrdm_lost_power, NULL);
+}