drivers: firmware: psci: Announce support for OS initiated suspend mode

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 (OSI) mode is optional.

In some cases it's interesting for the user/developer to know if
the OSI mode is supported by the PSCI FW, so print a message to
the log if that is the case.

Co-developed-by: Lina Iyer <lina.iyer@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

2 files changed, 25 insertions, 1 deletions

diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
index e480e0af632c..eabd01383cd6 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() ?
@@ -659,10 +664,24 @@ 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