ARM: psci: implement PSCI client driver

System reset on the STM32MP may be done via PSCI when running TF-A
as first-stage boot loader. Provide a PSCI driver to simplify using it:

- A psci_invoke function is exported, so other code can use it
- A fixup for the PSCI device tree node is registered
- A reset and poweroff handler via PSCI is registered for PSCI >= v0.2

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 21 insertions, 2 deletions

diff --git a/arch/arm/include/asm/psci.h b/arch/arm/include/asm/psci.h
index f2db967f3a..b616e4b20e 100644
--- a/arch/arm/include/asm/psci.h
+++ b/arch/arm/include/asm/psci.h
@@ -18,8 +18,9 @@
 #ifndef __ARM_PSCI_H__
 #define __ARM_PSCI_H__
 
-#define ARM_PSCI_VER_1_0		(0x00010000)
-#define ARM_PSCI_VER_0_2		(0x00000002)
+#define ARM_PSCI_VER(major, minor)	(((major) << 16) | (minor))
+#define ARM_PSCI_VER_1_0		ARM_PSCI_VER(1,0)
+#define ARM_PSCI_VER_0_2		ARM_PSCI_VER(0,2)
 
 /* PSCI 0.1 interface */
 #define ARM_PSCI_FN_BASE		0x95c1ba5e
@@ -106,6 +107,24 @@ static inline void psci_set_ops(struct psci_ops *ops)
 }
 #endif
 
+#ifdef CONFIG_ARM_PSCI_CLIENT
+int psci_invoke(ulong function, ulong arg0, ulong arg1, ulong arg2,
+		ulong *result);
+
+int psci_get_version(void);
+#else
+static inline int psci_invoke(ulong function, ulong arg0, ulong arg1, ulong arg2,
+		ulong *result)
+{
+	return -ENOSYS;
+}
+
+static inline int psci_get_version(void)
+{
+	return -ENOSYS;
+}
+#endif
+
 void psci_cpu_entry(void);
 
 #ifdef CONFIG_ARM_PSCI_DEBUG