Re: [PATCH v9 07/21] ACPI / sleep: Introduce arm64 specific acpi_sleep.c

[G Gregory <graeme.gregory@linaro.org>]

On 4 March 2015 at 22:38, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
> On Wednesday, February 25, 2015 04:39:47 PM Hanjun Guo wrote:
>> From: Graeme Gregory <graeme.gregory@linaro.org>
>>
>> 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 <rjw@rjwysocki.net>
>> Tested-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
>> Tested-by: Yijing Wang <wangyijing@huawei.com>
>> Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
>> Tested-by: Jon Masters <jcm@redhat.com>
>> Tested-by: Timur Tabi <timur@codeaurora.org>
>> Tested-by: Robert Richter <rrichter@cavium.com>
>> Acked-by: Robert Richter <rrichter@cavium.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>
>> ---
>>  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