mfd : Check if the other db8500 core is in WFI

This patch allows to check if the other core is in WFI
mode. It is the last check the idle routine has to do before
entering into the retention state.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

drivers/mfd/db8500-prcmu.c

@@ -903,6 +903,18 @@ bool db8500_prcmu_pending_irq(void)
 	return false;
 }
 
+/*
+ * This function checks if the specified cpu is in in WFI. It's usage
+ * makes sense only if the gic is decoupled with the db8500_prcmu_gic_decouple
+ * function. Of course passing smp_processor_id() to this function will
+ * always return false...
+ */
+bool db8500_prcmu_is_cpu_in_wfi(int cpu)
+{
+	return readl(PRCM_ARM_WFI_STANDBY) & cpu ? PRCM_ARM_WFI_STANDBY_WFI1 :
+		     PRCM_ARM_WFI_STANDBY_WFI0;
+}
+
 /*
  * This function copies the gic SPI settings to the prcmu in order to
  * monitor them and abort/finish the retention/off sequence or state.

drivers/mfd/dbx500-prcmu-regs.h

@@ -79,6 +79,8 @@
 
 /* ARM WFI Standby signal register */
 #define PRCM_ARM_WFI_STANDBY    (_PRCMU_BASE + 0x130)
+#define PRCM_ARM_WFI_STANDBY_WFI0               0x08
+#define PRCM_ARM_WFI_STANDBY_WFI1               0x10
 #define PRCM_IOCR		(_PRCMU_BASE + 0x310)
 #define PRCM_IOCR_IOFORCE			0x1
 

include/linux/mfd/db8500-prcmu.h

@@ -585,6 +585,7 @@ int db8500_prcmu_gic_recouple(void);
 int db8500_prcmu_copy_gic_settings(void);
 bool db8500_prcmu_gic_pending_irq(void);
 bool db8500_prcmu_pending_irq(void);
+bool db8500_prcmu_is_cpu_in_wfi(int cpu);
 void db8500_prcmu_enable_wakeups(u32 wakeups);
 int db8500_prcmu_set_epod(u16 epod_id, u8 epod_state);
 int db8500_prcmu_request_clock(u8 clock, bool enable);

include/linux/mfd/dbx500-prcmu.h

@@ -305,6 +305,14 @@ static inline bool prcmu_gic_pending_irq(void)
 		return db8500_prcmu_gic_pending_irq();
 }
 
+static inline bool prcmu_is_cpu_in_wfi(int cpu)
+{
+	if (cpu_is_u5500())
+		return -EINVAL;
+	else
+		return db8500_prcmu_is_cpu_in_wfi(cpu);
+}
+
 static inline int prcmu_copy_gic_settings(void)
 {
 	if (cpu_is_u5500())