[PATCH] drivers: firmware: psci: Add support for cpu suspend mode as per psci v1.0 spec

[Vikas C Sajjan]

According to section 5.1.16 of PSCI spec,
an optional feature called PSCI_SET_SUSPEND_MODE was added in v1.0.
This patch adds the support for the same.

Signed-off-by: Vikas C Sajjan <vikas.cha.sajjan at hpe.com>
---
 drivers/firmware/psci.c   | 20 +++++++++++++++++++-
 include/linux/psci.h      |  1 +
 include/uapi/linux/psci.h |  6 +++++-
 3 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
index 03e0458..c318972 100644
--- a/drivers/firmware/psci.c
+++ b/drivers/firmware/psci.c
@@ -91,6 +91,12 @@ static inline bool psci_has_ext_power_state(void)
 				PSCI_1_0_FEATURES_CPU_SUSPEND_PF_MASK;
 }
 
+static inline bool psci_has_OS_initiated_mode_support(void)
+{
+	return psci_cpu_suspend_feature &
+			PSCI_1_0_FEATURES_CPU_SUSPEND_OS_INITIATED_MODE_MASK;
+}
+
 static inline bool psci_power_state_loses_context(u32 state)
 {
 	const u32 mask = psci_has_ext_power_state() ?
@@ -145,6 +151,14 @@ static int psci_to_linux_errno(int errno)
 
 	return -EINVAL;
 }
+static int psci_set_cpu_suspend_mode(bool suspend_mode)
+{
+	int err;
+
+	err = invoke_psci_fn(PSCI_FN_NATIVE(1_0, SUSPEND_MODE),
+						suspend_mode, 0, 0);
+	return psci_to_linux_errno(err);
+}
 
 static u32 psci_get_version(void)
 {
@@ -397,8 +411,12 @@ static void __init psci_init_cpu_suspend(void)
 {
 	int feature = psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND]);
 
-	if (feature != PSCI_RET_NOT_SUPPORTED)
+	if (feature != PSCI_RET_NOT_SUPPORTED) {
 		psci_cpu_suspend_feature = feature;
+		if (psci_has_OS_initiated_mode_support())
+			psci_ops.set_cpu_suspend_mode =
+						psci_set_cpu_suspend_mode;
+	}
 }
 
 /*
diff --git a/include/linux/psci.h b/include/linux/psci.h
index bdea1cb..c040502 100644
--- a/include/linux/psci.h
+++ b/include/linux/psci.h
@@ -33,6 +33,7 @@ struct psci_operations {
 	int (*affinity_info)(unsigned long target_affinity,
 			unsigned long lowest_affinity_level);
 	int (*migrate_info_type)(void);
+	int (*set_cpu_suspend_mode)(bool);
 };
 
 extern struct psci_operations psci_ops;
diff --git a/include/uapi/linux/psci.h b/include/uapi/linux/psci.h
index 3d7a0fc..097c95e 100644
--- a/include/uapi/linux/psci.h
+++ b/include/uapi/linux/psci.h
@@ -50,6 +50,8 @@
 #define PSCI_1_0_FN_SYSTEM_SUSPEND		PSCI_0_2_FN(14)
 
 #define PSCI_1_0_FN64_SYSTEM_SUSPEND		PSCI_0_2_FN64(14)
+#define PSCI_1_0_FN_SUSPEND_MODE		PSCI_0_2_FN(0xF)
+#define PSCI_1_0_FN64_SUSPEND_MODE		PSCI_0_2_FN64(0xF)
 
 /* PSCI v0.2 power state encoding for CPU_SUSPEND function */
 #define PSCI_0_2_POWER_STATE_ID_MASK		0xffff
@@ -90,8 +92,10 @@
 
 /* PSCI features decoding (>=1.0) */
 #define PSCI_1_0_FEATURES_CPU_SUSPEND_PF_SHIFT	1
+#define PSCI_1_0_FEATURES_CPU_SUSPEND_OS_INITIATED_MODE_MASK 1
 #define PSCI_1_0_FEATURES_CPU_SUSPEND_PF_MASK	\
-			(0x1 << PSCI_1_0_FEATURES_CPU_SUSPEND_PF_SHIFT)
+			((0x1 << PSCI_1_0_FEATURES_CPU_SUSPEND_PF_SHIFT)| \
+			PSCI_1_0_FEATURES_CPU_SUSPEND_OS_INITIATED_MODE_MASK)
 
 /* PSCI return values (inclusive of all PSCI versions) */
 #define PSCI_RET_SUCCESS			0
-- 
1.9.1