mfd : ux500 - decouple/recouple gic from the PRCMU

This patch allows to decouple and recouple the gic from the PRCMU.
This is needed to put the A9 core in retention mode with the cpuidle
driver.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

3 files changed, 50 insertions, 0 deletions

diff --git a/drivers/mfd/db8500-prcmu.c b/drivers/mfd/db8500-prcmu.c
index af8e0efedbe..9baf4cd7f07 100644
--- a/drivers/mfd/db8500-prcmu.c
+++ b/drivers/mfd/db8500-prcmu.c
@@ -787,6 +787,38 @@ int db8500_prcmu_set_power_state(u8 state, bool keep_ulp_clk, bool keep_ap_pll)
 	return 0;
 }
 
+#define PRCMU_A9_MASK_REQ               0x00000328
+#define PRCMU_A9_MASK_REQ_MASK          0x00000001
+#define PRCMU_GIC_DELAY                 1
+
+/* This function decouple the gic from the prcmu */
+int db8500_prcmu_gic_decouple(void)
+{
+	u32 val = readl(_PRCMU_BASE + PRCMU_A9_MASK_REQ);
+
+	/* Set bit 0 register value to 1 */
+	writel(val | PRCMU_A9_MASK_REQ_MASK, _PRCMU_BASE + PRCMU_A9_MASK_REQ);
+
+	/* Make sure the register is updated */
+	readl(_PRCMU_BASE + PRCMU_A9_MASK_REQ);
+
+	/* Wait a few cycles for the gic mask completion */
+	udelay(PRCMU_GIC_DELAY);
+
+	return 0;
+}
+
+/* This function recouple the gic with the prcmu */
+int db8500_prcmu_gic_recouple(void)
+{
+	u32 val = readl(_PRCMU_BASE + PRCMU_A9_MASK_REQ);
+
+	/* Set bit 0 register value to 0 */
+	writel(val & ~PRCMU_A9_MASK_REQ_MASK, _PRCMU_BASE + PRCMU_A9_MASK_REQ);
+
+	return 0;
+}
+
 /* This function should only be called while mb0_transfer.lock is held. */
 static void config_wakeups(void)
 {
diff --git a/include/linux/mfd/db8500-prcmu.h b/include/linux/mfd/db8500-prcmu.h
index 60d27f7bfc1..a3c7eba8e6f 100644
--- a/include/linux/mfd/db8500-prcmu.h
+++ b/include/linux/mfd/db8500-prcmu.h
@@ -536,6 +536,8 @@ int prcmu_load_a9wdog(u8 id, u32 val);
 
 void db8500_prcmu_system_reset(u16 reset_code);
 int db8500_prcmu_set_power_state(u8 state, bool keep_ulp_clk, bool keep_ap_pll);
+int db8500_prcmu_gic_decouple(void);
+int db8500_prcmu_gic_recouple(void);
 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);
diff --git a/include/linux/mfd/dbx500-prcmu.h b/include/linux/mfd/dbx500-prcmu.h
index bac942f959c..d38cf7d9657 100644
--- a/include/linux/mfd/dbx500-prcmu.h
+++ b/include/linux/mfd/dbx500-prcmu.h
@@ -237,6 +237,22 @@ static inline int prcmu_set_power_state(u8 state, bool keep_ulp_clk,
 			keep_ap_pll);
 }
 
+static inline int prcmu_gic_decouple(void)
+{
+	if (machine_is_u5500())
+		return -EINVAL;
+	else
+		return db8500_prcmu_gic_decouple();
+}
+
+static inline int prcmu_gic_recouple(void)
+{
+	if (machine_is_u5500())
+		return -EINVAL;
+	else
+		return db8500_prcmu_gic_recouple();
+}
+
 static inline int prcmu_set_epod(u16 epod_id, u8 epod_state)
 {
 	if (machine_is_u5500())