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

[Rafael J. Wysocki]

On Thursday, March 05, 2015 12:25:54 AM Rafael J. Wysocki wrote:
> On Wednesday, March 04, 2015 10:49:25 PM G Gregory wrote:
> > On 4 March 2015 at 22:38, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote:
> > > On Wednesday, February 25, 2015 04:39:47 PM Hanjun Guo wrote:
> > >> From: Graeme Gregory <graeme.gregory@xxxxxxxxxx>
> > >>
> > >> 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@xxxxxxxxxxxxx>
> > >> Tested-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@xxxxxxx>
> > >> Tested-by: Yijing Wang <wangyijing@xxxxxxxxxx>
> > >> Tested-by: Mark Langsdorf <mlangsdo@xxxxxxxxxx>
> > >> Tested-by: Jon Masters <jcm@xxxxxxxxxx>
> > >> Tested-by: Timur Tabi <timur@xxxxxxxxxxxxxx>
> > >> Tested-by: Robert Richter <rrichter@xxxxxxxxxx>
> > >> Acked-by: Robert Richter <rrichter@xxxxxxxxxx>
> > >> Signed-off-by: Graeme Gregory <graeme.gregory@xxxxxxxxxx>
> > >> Signed-off-by: Tomasz Nowicki <tomasz.nowicki@xxxxxxxxxx>
> > >> Signed-off-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
> > >> ---
> > >>  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                                        += $(arm64-obj-m)
> > >> diff --git a/arch/arm64/kernel/acpi_sleep.c b/arch/arm64/kernel/acpi_sleep.c
> > >> new file mode 100644
> > >> index 0000000..54578ef
> > >> --- /dev/null
> > >> +++ b/arch/arm64/kernel/acpi_sleep.c
> > >> @@ -0,0 +1,28 @@
> > >> +/*
> > >> + *  ARM64 Specific Sleep Functionality
> > >> + *
> > >> + *  Copyright (C) 2013-2014, Linaro Ltd.
> > >> + *      Author: Graeme Gregory <graeme.gregory@xxxxxxxxxx>
> > >> + *
> > >> + *  This program is free software; you can redistribute it and/or modify
> > >> + *  it under the terms of the GNU General Public License version 2 as
> > >> + *  published by the Free Software Foundation.
> > >> + */
> > >> +
> > >> +#include <linux/acpi.h>
> > >> +
> > >> +/*
> > >> + * Currently the ACPI 5.1 standard does not define S states in a
> > >> + * manner which is usable for ARM64. These two stubs are sufficient
> > >> + * that system initialises and device PM works.
> > >> + */
> > >> +u32 acpi_target_system_state(void)
> > >> +{
> > >> +     return ACPI_STATE_S0;
> > >> +}
> > >> +EXPORT_SYMBOL_GPL(acpi_target_system_state);
> > >> +
> > >> +int __init acpi_sleep_init(void)
> > >> +{
> > >> +     return -ENOSYS;
> > >> +}
> > >> diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
> > >> index 623b117..c32edf5 100644
> > >> --- a/drivers/acpi/Makefile
> > >> +++ b/drivers/acpi/Makefile
> > >> @@ -23,7 +23,9 @@ acpi-y                              += nvs.o
> > >>
> > >>  # Power management related files
> > >>  acpi-y                               += wakeup.o
> > >> +ifneq (,$(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.
> 
> > 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.


-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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