[PATCH v4 07/13] ARM64 / ACPI: Introduce lowlevel suspend function

[Hanjun Guo]

From: Graeme Gregory <graeme.gregory at linaro.org>

acpi_wakeup_address is used on x86 as the address bios jumps into
when machine wakes up from suspend. As arm64 does not have such a
bios this mechanism will be provided by other means. But the define
is still required inside the acpi core.

Introduce a null stub for acpi_suspend_lowlevel as this is also
required by core. This will be filled in when standards are
defined for arm64 ACPI global power states.

Reviewed-by: Grant Likely <grant.likely at linaro.org>
Signed-off-by: Graeme Gregory <graeme.gregory at linaro.org>
Signed-off-by: Hanjun Guo <hanjun.guo at linaro.org>
---
 arch/arm64/include/asm/acpi.h |   12 ++++++++++++
 drivers/acpi/plat/arm-core.c  |    7 +++++++
 2 files changed, 19 insertions(+)

diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
index 3ea6b84..a93e8ae 100644
--- a/arch/arm64/include/asm/acpi.h
+++ b/arch/arm64/include/asm/acpi.h
@@ -39,6 +39,18 @@ static inline void disable_acpi(void)
  */
 #define cpu_physical_id(cpu) -1
 
+/*
+ * Low-level suspend routine.
+ *
+ * ACPI S-states for ARM64 have to be defined
+ * and approved before doing anything else, maybe
+ * we need update the ACPI spec, here just we
+ * just introduce function and macro needed by
+ * ACPI core, and revisit them when the spec is ready.
+ */
+extern int (*acpi_suspend_lowlevel)(void);
+#define acpi_wakeup_address (0)
+
 static inline bool acpi_arch_is_smp(void)
 {
 	return 1;
diff --git a/drivers/acpi/plat/arm-core.c b/drivers/acpi/plat/arm-core.c
index cf46c25..0155a98 100644
--- a/drivers/acpi/plat/arm-core.c
+++ b/drivers/acpi/plat/arm-core.c
@@ -129,3 +129,10 @@ static int __init parse_acpi(char *arg)
 	return 0;
 }
 early_param("acpi", parse_acpi);
+
+/*
+ * acpi_suspend_lowlevel() - save kernel state and suspend.
+ *
+ * TBD when ARM/ARM64 starts to support suspend...
+ */
+int (*acpi_suspend_lowlevel)(void);
-- 
1.7.9.5