arm64: psci: factor invocation code to drivers

To enable sharing with arm, move the core PSCI framework code to
drivers/firmware. This results in a minor gain in lines of code, but
this will quickly be amortised by the removal of code currently
duplicated in arch/arm.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
diff --git a/include/linux/psci.h b/include/linux/psci.h
new file mode 100644
index 0000000..a682fcc
--- /dev/null
+++ b/include/linux/psci.h
@@ -0,0 +1,52 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Copyright (C) 2015 ARM Limited
+ */
+
+#ifndef __LINUX_PSCI_H
+#define __LINUX_PSCI_H
+
+#include <linux/init.h>
+#include <linux/types.h>
+
+#define PSCI_POWER_STATE_TYPE_STANDBY		0
+#define PSCI_POWER_STATE_TYPE_POWER_DOWN	1
+
+bool psci_tos_resident_on(int cpu);
+
+struct psci_operations {
+	int (*cpu_suspend)(u32 state, unsigned long entry_point);
+	int (*cpu_off)(u32 state);
+	int (*cpu_on)(unsigned long cpuid, unsigned long entry_point);
+	int (*migrate)(unsigned long cpuid);
+	int (*affinity_info)(unsigned long target_affinity,
+			unsigned long lowest_affinity_level);
+	int (*migrate_info_type)(void);
+};
+
+extern struct psci_operations psci_ops;
+
+#if defined(CONFIG_ARM_PSCI_FW)
+int __init psci_dt_init(void);
+#else
+static inline int psci_dt_init(void) { return 0; }
+#endif
+
+#if defined(CONFIG_ARM_PSCI_FW) && defined(CONFIG_ACPI)
+int __init psci_acpi_init(void);
+bool __init acpi_psci_present(void);
+bool __init acpi_psci_use_hvc(void);
+#else
+static inline int psci_acpi_init(void) { return 0; }
+static inline bool acpi_psci_present(void) { return false; }
+#endif
+
+#endif /* __LINUX_PSCI_H */