[PATCH v8 18/26] drivers: firmware: psci: Announce support for OS initiated suspend mode

[Ulf Hansson <ulf.hansson@linaro.org>]

PSCI firmware v1.0+, supports two different modes for CPU_SUSPEND. The
Platform Coordinated mode, which is the default and mandatory mode, while
support for the OS initiated mode is optional.

This change introduces initial support for the OS initiated mode, in way
that it adds the related PSCI bits from the spec and prints a message in
the log to inform whether the mode is supported by the PSCI FW.

Cc: Lina Iyer <ilina@codeaurora.org>
Co-developed-by: Lina Iyer <lina.iyer@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 drivers/firmware/psci/psci.c | 21 ++++++++++++++++++++-
 include/uapi/linux/psci.h    |  5 +++++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
index 38881007584e..e8f4f8444ff1 100644
--- a/drivers/firmware/psci/psci.c
+++ b/drivers/firmware/psci/psci.c
@@ -95,6 +95,11 @@ static inline bool psci_has_ext_power_state(void)
 				PSCI_1_0_FEATURES_CPU_SUSPEND_PF_MASK;
 }
 
+static inline bool psci_has_osi_support(void)
+{
+	return psci_cpu_suspend_feature & PSCI_1_0_OS_INITIATED;
+}
+
 static inline bool psci_power_state_loses_context(u32 state)
 {
 	const u32 mask = psci_has_ext_power_state() ?
@@ -658,10 +663,24 @@ static int __init psci_0_1_init(struct device_node *np)
 	return 0;
 }
 
+static int __init psci_1_0_init(struct device_node *np)
+{
+	int err;
+
+	err = psci_0_2_init(np);
+	if (err)
+		return err;
+
+	if (psci_has_osi_support())
+		pr_info("OSI mode supported.\n");
+
+	return 0;
+}
+
 static const struct of_device_id psci_of_match[] __initconst = {
 	{ .compatible = "arm,psci",	.data = psci_0_1_init},
 	{ .compatible = "arm,psci-0.2",	.data = psci_0_2_init},
-	{ .compatible = "arm,psci-1.0",	.data = psci_0_2_init},
+	{ .compatible = "arm,psci-1.0",	.data = psci_1_0_init},
 	{},
 };
 
diff --git a/include/uapi/linux/psci.h b/include/uapi/linux/psci.h
index b3bcabe380da..581f72085c33 100644
--- a/include/uapi/linux/psci.h
+++ b/include/uapi/linux/psci.h
@@ -49,6 +49,7 @@
 
 #define PSCI_1_0_FN_PSCI_FEATURES		PSCI_0_2_FN(10)
 #define PSCI_1_0_FN_SYSTEM_SUSPEND		PSCI_0_2_FN(14)
+#define PSCI_1_0_FN_SET_SUSPEND_MODE		PSCI_0_2_FN(15)
 
 #define PSCI_1_0_FN64_SYSTEM_SUSPEND		PSCI_0_2_FN64(14)
 
@@ -97,6 +98,10 @@
 #define PSCI_1_0_FEATURES_CPU_SUSPEND_PF_MASK	\
 			(0x1 << PSCI_1_0_FEATURES_CPU_SUSPEND_PF_SHIFT)
 
+#define PSCI_1_0_OS_INITIATED			BIT(0)
+#define PSCI_1_0_SUSPEND_MODE_PC		0
+#define PSCI_1_0_SUSPEND_MODE_OSI		1
+
 /* PSCI return values (inclusive of all PSCI versions) */
 #define PSCI_RET_SUCCESS			0
 #define PSCI_RET_NOT_SUPPORTED			-1
-- 
2.17.1