ARM: OMAP3: CPUidle: Make use of CPU PM notifiers

Save VFP CPU context using CPU PM notifier chain. VFP context
is lost when CPU hits OFF state.

Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Vishwanath BS <vishwanath.bs@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>

arch/arm/mach-omap2/cpuidle34xx.c

@@ -25,6 +25,7 @@
 #include <linux/sched.h>
 #include <linux/cpuidle.h>
 #include <linux/export.h>
+#include <linux/cpu_pm.h>
 
 #include <plat/prcm.h>
 #include <plat/irqs.h>
@@ -124,9 +125,23 @@ static int omap3_enter_idle(struct cpuidle_device *dev,
 		pwrdm_for_each_clkdm(core_pd, _cpuidle_deny_idle);
 	}
 
+	/*
+	 * Call idle CPU PM enter notifier chain so that
+	 * VFP context is saved.
+	 */
+	if (mpu_state == PWRDM_POWER_OFF)
+		cpu_pm_enter();
+
 	/* Execute ARM wfi */
 	omap_sram_idle();
 
+	/*
+	 * Call idle CPU PM enter notifier chain to restore
+	 * VFP context.
+	 */
+	if (pwrdm_read_prev_pwrst(mpu_pd) == PWRDM_POWER_OFF)
+		cpu_pm_exit();
+
 	/* Re-allow idle for C1 */
 	if (index == 0) {
 		pwrdm_for_each_clkdm(mpu_pd, _cpuidle_allow_idle);