ACPI / sleep: Introduce CONFIG_ACPI_SYSTEM_POWER_STATES_SUPPORT

ACPI 5.1 does not currently support S states for ARM64 hardware but
ACPI code will call acpi_target_system_state() and acpi_sleep_init()
for device power management, so introduce
CONFIG_ACPI_SYSTEM_POWER_STATES_SUPPORT and select it for x86 and
ia64 only to make sleep functions available, and also introduce stub
function to allow other drivers to function until S states are defined
for ARM64.

It will be no functional change for x86 and IA64.

Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Graeme Gregory <graeme.gregory@linaro.org>
Signed-off-by: Tomasz Nowicki <tomasz.nowicki@linaro.org>
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arch/ia64/Kconfig

@@ -10,6 +10,7 @@ config IA64
 	select ARCH_MIGHT_HAVE_PC_SERIO
 	select PCI if (!IA64_HP_SIM)
 	select ACPI if (!IA64_HP_SIM)
+	select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
 	select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
 	select HAVE_UNSTABLE_SCHED_CLOCK
 	select HAVE_IDE

arch/x86/Kconfig

@@ -22,6 +22,7 @@ config X86_64
 ### Arch settings
 config X86
 	def_bool y
+	select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
 	select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
 	select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
 	select ARCH_HAS_FAST_MULTIPLIER

drivers/acpi/Kconfig

@@ -48,9 +48,13 @@ config ACPI_LEGACY_TABLES_LOOKUP
 config ARCH_MIGHT_HAVE_ACPI_PDC
 	bool
 
+config ACPI_SYSTEM_POWER_STATES_SUPPORT
+	bool
+
 config ACPI_SLEEP
 	bool
 	depends on SUSPEND || HIBERNATION
+	depends on ACPI_SYSTEM_POWER_STATES_SUPPORT
 	default y
 
 config ACPI_PROCFS_POWER

drivers/acpi/Makefile

@@ -23,7 +23,7 @@ acpi-y				+= nvs.o
 
 # Power management related files
 acpi-y				+= wakeup.o
-acpi-y				+= sleep.o
+acpi-$(CONFIG_ACPI_SYSTEM_POWER_STATES_SUPPORT) += sleep.o
 acpi-y				+= device_pm.o
 acpi-$(CONFIG_ACPI_SLEEP)	+= proc.o
 

drivers/acpi/internal.h

@@ -161,7 +161,11 @@ void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit);
 /*--------------------------------------------------------------------------
                                   Suspend/Resume
   -------------------------------------------------------------------------- */
+#ifdef CONFIG_ACPI_SYSTEM_POWER_STATES_SUPPORT
 extern int acpi_sleep_init(void);
+#else
+static inline int acpi_sleep_init(void) { return -ENXIO; }
+#endif
 
 #ifdef CONFIG_ACPI_SLEEP
 int acpi_sleep_proc_init(void);