On 4 March 2015 at 22:38, Rafael J. Wysocki [off-list ref] wrote:

On Wednesday, February 25, 2015 04:39:47 PM Hanjun Guo wrote:

quoted

From: Graeme Gregory <redacted>

ACPI 5.1 does not currently support S states for ARM64 hardware but
ACPI code will call acpi_target_system_state() for device power
management, so introduce acpi_sleep.c to allow other drivers to function
until S states are defined.

Since it is arm64 specific stub holder, so let acpi_sleep.c to ARM64
specific.

TODO: merge this with drivers/acpi/sleep.c once we fix the specification.

CC: Rafael J. Wysocki <redacted>
Tested-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Tested-by: Yijing Wang <redacted>
Tested-by: Mark Langsdorf <redacted>
Tested-by: Jon Masters <redacted>
Tested-by: Timur Tabi <redacted>
Tested-by: Robert Richter <redacted>
Acked-by: Robert Richter <redacted>
Signed-off-by: Graeme Gregory <redacted>
Signed-off-by: Tomasz Nowicki <redacted>
Signed-off-by: Hanjun Guo <redacted>
---
 arch/arm64/kernel/Makefile     |  2 +-
 arch/arm64/kernel/acpi_sleep.c | 28 ++++++++++++++++++++++++++++
 drivers/acpi/Makefile          |  2 ++
 3 files changed, 31 insertions(+), 1 deletion(-)
 create mode 100644 arch/arm64/kernel/acpi_sleep.c

diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 218eb7e..4435943 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile

@@ -34,7 +34,7 @@ arm64-obj-$(CONFIG_KGDB)            += kgdb.o
 arm64-obj-$(CONFIG_EFI)                      += efi.o efi-stub.o efi-entry.o
 arm64-obj-$(CONFIG_PCI)                      += pci.o
 arm64-obj-$(CONFIG_ARMV8_DEPRECATED) += armv8_deprecated.o
-arm64-obj-$(CONFIG_ACPI)             += acpi.o
+arm64-obj-$(CONFIG_ACPI)             += acpi.o acpi_sleep.o

 obj-y                                        += $(arm64-obj-y) vdso/
 obj-m                                        += $(arm64-obj-m)

diff --git a/arch/arm64/kernel/acpi_sleep.c b/arch/arm64/kernel/acpi_sleep.c
new file mode 100644
index 0000000..54578ef
--- /dev/null
+++ b/arch/arm64/kernel/acpi_sleep.c

@@ -0,0 +1,28 @@
+/*
+ *  ARM64 Specific Sleep Functionality
+ *
+ *  Copyright (C) 2013-2014, Linaro Ltd.
+ *      Author: Graeme Gregory <graeme.gregory@linaro.org>
+ *
+ *  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.
+ */
+
+#include <linux/acpi.h>
+
+/*
+ * Currently the ACPI 5.1 standard does not define S states in a
+ * manner which is usable for ARM64. These two stubs are sufficient
+ * that system initialises and device PM works.
+ */
+u32 acpi_target_system_state(void)
+{
+     return ACPI_STATE_S0;
+}
+EXPORT_SYMBOL_GPL(acpi_target_system_state);
+
+int __init acpi_sleep_init(void)
+{
+     return -ENOSYS;
+}

diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 623b117..c32edf5 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile

@@ -23,7 +23,9 @@ acpi-y                              += nvs.o

 # Power management related files
 acpi-y                               += wakeup.o
+ifneq (,$(findstring $(ARCH),x86 ia64))

This is super-ugly.  Isn't there a better way to do that?

Its the standard example in the GNU Make manual, I would certainly
love if someone had a batter suggestion.

Graeme