On Thu, Mar 05, 2015 at 12:16:29AM +0000, Rafael J. Wysocki wrote:

On Thursday, March 05, 2015 12:25:54 AM Rafael J. Wysocki wrote:

quoted

On Wednesday, March 04, 2015 10:49:25 PM G Gregory wrote:

quoted

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

quoted

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,

It is never used in the kernel this way, though, and I'm not going to let
that slip through.

quoted

I would certainly love if someone had a batter suggestion.

Define ACPI_GENERIC_SLEEP in drivers/acpi/Kconfig as

	config ACPI_GENERIC_SLEEP
		bool
		depends on IA64 || X86

and build the file conditional on that.

Or define

	config ACPI_GENERIC_SLEEP
		bool

and then make both x86 and ia64 do

	select ACPI_GENERIC_SLEEP if ACPI

which kind of will make it clear where the choice takes place.

While at it, use the newly defined config entry to add the required static
inline in the respective headers and get rid of acpi_sleep.c from arm64.

Thanks,
Lorenzo