[PATCH] ux500 : decouple/recouple gic from the PRCMU

[daniel.lezcano@linaro.org (Daniel Lezcano)]

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>
---
 drivers/mfd/db8500-prcmu.c       |   42 ++++++++++++++++++++++++++++++++++++++
 include/linux/mfd/db8500-prcmu.h |    2 +
 include/linux/mfd/dbx500-prcmu.h |   16 ++++++++++++++
 3 files changed, 60 insertions(+), 0 deletions(-)

diff --git a/drivers/mfd/db8500-prcmu.c b/drivers/mfd/db8500-prcmu.c
index af8e0ef..c708431 100644
--- a/drivers/mfd/db8500-prcmu.c
+++ b/drivers/mfd/db8500-prcmu.c
@@ -528,6 +528,10 @@ static const char *hwacc_ret_regulator_name[NUM_HW_ACC] = {
 
 #define PRCMU_PLLDSI_LOCKP_LOCKED	0x3
 
+#define PRCMU_A9_MASK_REQ               0x00000328
+#define PRCMU_A9_MASK_REQ_MASK          0x00000001
+#define PRCMU_A9_MASK_ACK               0x0000032C
+
 static struct {
 	u8 project_number;
 	u8 api_version;
@@ -787,6 +791,44 @@ int db8500_prcmu_set_power_state(u8 state, bool keep_ulp_clk, bool keep_ap_pll)
 	return 0;
 }
 
+/*
+ * prcmu_gic_mask - apply the mask to the mask request
+ * register. This mask has the bits [1-31] reserved and
+ * the request applies to the bit 0 of this register.
+ */
+static inline void prcmu_gic_mask(u32 mask)
+{
+	u32 val = readl(_PRCMU_BASE + PRCMU_A9_MASK_REQ);
+	writel((val & ~PRCMU_A9_MASK_REQ_MASK) | mask,
+	       _PRCMU_BASE + PRCMU_A9_MASK_REQ);
+}
+
+/*
+ * db8500_prcmu_gic_disable - This function decouple the gic
+ * from the prcmu.
+ */
+void db8500_prcmu_gic_disable(void)
+{
+	prcmu_gic_mask(PRCMU_A9_MASK_REQ_MASK);
+
+	/* Wait for gic mask register update */
+	while (!(readl(_PRCMU_BASE + PRCMU_A9_MASK_REQ) &
+		 PRCMU_A9_MASK_REQ_MASK))
+		cpu_relax();
+
+	/* Wait a few cycles for the gic mask completion */
+	udelay(1);
+}
+
+/*
+ * db8500_prcmu_gic_enable - This function recouple the gic
+ * with the prcmu.
+ */
+void db8500_prcmu_gic_enable(void)
+{
+	prcmu_gic_mask(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 60d27f7..4a1032c 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);
+void db8500_prcmu_gic_disable(void);
+void db8500_prcmu_gic_enable(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 bac942f..a5fee69 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 void prcmu_gic_disable(void)
+{
+	if (machine_is_u5500())
+		return;
+	else
+		return db8500_prcmu_gic_disable();
+}
+
+static inline void prcmu_gic_enable(void)
+{
+	if (machine_is_u5500())
+		return;
+	else
+		return db8500_prcmu_gic_enable();
+}
+
 static inline int prcmu_set_epod(u16 epod_id, u8 epod_state)
 {
 	if (machine_is_u5500())
-- 
1.7.5.4