Commit Graph

101 Commits

Author SHA1 Message Date
Russell King (Oracle)
c4dd854f74 cpu-hotplug: Provide prototypes for arch CPU registration
Provide common prototypes for arch_register_cpu() and
arch_unregister_cpu(). These are called by acpi_processor.c, with weak
versions, so the prototype for this is already set. It is generally not
necessary for function prototypes to be conditional on preprocessor macros.

Some architectures (e.g. Loongarch) are missing the prototype for this, and
rather than add it to Loongarch's asm/cpu.h, do the job once for everyone.

Since this covers everyone, remove the now unnecessary prototypes in
asm/cpu.h, and therefore remove the 'static' from one of ia64's
arch_register_cpu() definitions.

[ tglx: Bring back the ia64 part and remove the ACPI prototypes ]

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/E1qkoRr-0088Q8-Da@rmk-PC.armlinux.org.uk
2023-10-11 14:27:37 +02:00
Sudeep Holla
05e6b43137 ACPI: processor: Silence missing prototype warnings
Silence the following warnings when built with W=1:

 | CC   drivers/acpi/acpi_processor.c
 |      warning: no previous prototype for 'arch_register_cpu' [-Wmissing-prototypes]
 |              int __weak arch_register_cpu(int cpu)
 |                         ^
 | CC   drivers/acpi/acpi_processor.c
 |      warning: no previous prototype for 'arch_unregister_cpu' [-Wmissing-prototypes]
 |              void __weak arch_unregister_cpu(int cpu) {}
 |                          ^

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2022-11-23 19:36:46 +01:00
Sudeep Holla
314363737c ACPI: processor_idle: Silence missing prototype warnings
Silence the following warnings when built with W=1:

 | CC   drivers/acpi/processor_idle.c
 |      warning: no previous prototype for 'acpi_processor_ffh_lpi_probe' [-Wmissing-prototypes]
 |		int __weak acpi_processor_ffh_lpi_probe(unsigned int cpu)
 |                         ^
 | CC   drivers/acpi/processor_idle.c
 |      warning: no previous prototype for 'acpi_processor_ffh_lpi_enter' [-Wmissing-prototypes]
 |              int __weak acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
 |                         ^

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2022-11-23 19:36:40 +01:00
Riwen Lu
e414207d12 ACPI: processor: Drop leftover acpi_processor_get_limit_info() declaration
Commit 22e7551eb6 ("ACPI / processor: Remove acpi_processor_get_limit_info()"),
left it behind, so drop it.

Signed-off-by: Riwen Lu <luriwen@kylinos.cn>
Reviewed-by: Punit Agrawal <punit.agrawal@bytedance.com>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2022-06-29 19:01:23 +02:00
Riwen Lu
7fdc74da94 ACPI: processor: Split out thermal initialization from ACPI PSS
Commit 239708a3af ("ACPI: Split out ACPI PSS from ACPI Processor
driver"), moves processor thermal registration to acpi_pss_perf_init(),
which doesn't get executed if ACPI_CPU_FREQ_PSS is not enabled.

As ARM64 supports P-states using CPPC, it should be possible to also
support processor passive cooling even if PSS is not enabled. Split
out the processor thermal cooling register from ACPI PSS to support
this, and move it into a separate function in processor_thermal.c.

Signed-off-by: Riwen Lu <luriwen@kylinos.cn>
Reviewed-by: Punit Agrawal <punit.agrawal@bytedance.com>
[ rjw: Subject edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2022-06-29 18:51:22 +02:00
Andy Shevchenko
6fd13452c1 ACPI: processor: Replace kernel.h with the necessary inclusions
When kernel.h is used in the headers it adds a lot into dependency hell,
especially when there are circular dependencies are involved.

Replace kernel.h inclusion with the list of what is really being used.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2021-11-24 17:44:04 +01:00
Qian Cai
696ac2e3bf x86: ACPI: fix CPU hotplug deadlock
Similar to commit 0266d81e9b ("acpi/processor: Prevent cpu hotplug
deadlock") except this is for acpi_processor_ffh_cstate_probe():

"The problem is that the work is scheduled on the current CPU from the
hotplug thread associated with that CPU.

It's not required to invoke these functions via the workqueue because
the hotplug thread runs on the target CPU already.

Check whether current is a per cpu thread pinned on the target CPU and
invoke the function directly to avoid the workqueue."

 WARNING: possible circular locking dependency detected
 ------------------------------------------------------
 cpuhp/1/15 is trying to acquire lock:
 ffffc90003447a28 ((work_completion)(&wfc.work)){+.+.}-{0:0}, at: __flush_work+0x4c6/0x630

 but task is already holding lock:
 ffffffffafa1c0e8 (cpuidle_lock){+.+.}-{3:3}, at: cpuidle_pause_and_lock+0x17/0x20

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #1 (cpu_hotplug_lock){++++}-{0:0}:
 cpus_read_lock+0x3e/0xc0
 irq_calc_affinity_vectors+0x5f/0x91
 __pci_enable_msix_range+0x10f/0x9a0
 pci_alloc_irq_vectors_affinity+0x13e/0x1f0
 pci_alloc_irq_vectors_affinity at drivers/pci/msi.c:1208
 pqi_ctrl_init+0x72f/0x1618 [smartpqi]
 pqi_pci_probe.cold.63+0x882/0x892 [smartpqi]
 local_pci_probe+0x7a/0xc0
 work_for_cpu_fn+0x2e/0x50
 process_one_work+0x57e/0xb90
 worker_thread+0x363/0x5b0
 kthread+0x1f4/0x220
 ret_from_fork+0x27/0x50

 -> #0 ((work_completion)(&wfc.work)){+.+.}-{0:0}:
 __lock_acquire+0x2244/0x32a0
 lock_acquire+0x1a2/0x680
 __flush_work+0x4e6/0x630
 work_on_cpu+0x114/0x160
 acpi_processor_ffh_cstate_probe+0x129/0x250
 acpi_processor_evaluate_cst+0x4c8/0x580
 acpi_processor_get_power_info+0x86/0x740
 acpi_processor_hotplug+0xc3/0x140
 acpi_soft_cpu_online+0x102/0x1d0
 cpuhp_invoke_callback+0x197/0x1120
 cpuhp_thread_fun+0x252/0x2f0
 smpboot_thread_fn+0x255/0x440
 kthread+0x1f4/0x220
 ret_from_fork+0x27/0x50

 other info that might help us debug this:

 Chain exists of:
 (work_completion)(&wfc.work) --> cpuhp_state-up --> cpuidle_lock

 Possible unsafe locking scenario:

 CPU0                    CPU1
 ----                    ----
 lock(cpuidle_lock);
                         lock(cpuhp_state-up);
                         lock(cpuidle_lock);
 lock((work_completion)(&wfc.work));

 *** DEADLOCK ***

 3 locks held by cpuhp/1/15:
 #0: ffffffffaf51ab10 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x69/0x2f0
 #1: ffffffffaf51ad40 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x69/0x2f0
 #2: ffffffffafa1c0e8 (cpuidle_lock){+.+.}-{3:3}, at: cpuidle_pause_and_lock+0x17/0x20

 Call Trace:
 dump_stack+0xa0/0xea
 print_circular_bug.cold.52+0x147/0x14c
 check_noncircular+0x295/0x2d0
 __lock_acquire+0x2244/0x32a0
 lock_acquire+0x1a2/0x680
 __flush_work+0x4e6/0x630
 work_on_cpu+0x114/0x160
 acpi_processor_ffh_cstate_probe+0x129/0x250
 acpi_processor_evaluate_cst+0x4c8/0x580
 acpi_processor_get_power_info+0x86/0x740
 acpi_processor_hotplug+0xc3/0x140
 acpi_soft_cpu_online+0x102/0x1d0
 cpuhp_invoke_callback+0x197/0x1120
 cpuhp_thread_fun+0x252/0x2f0
 smpboot_thread_fn+0x255/0x440
 kthread+0x1f4/0x220
 ret_from_fork+0x27/0x50

Signed-off-by: Qian Cai <cai@lca.pw>
Tested-by: Borislav Petkov <bp@suse.de>
[ rjw: Subject ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-04-04 16:28:24 +02:00
Rafael J. Wysocki
3000ce3c52 cpufreq: Use per-policy frequency QoS
Replace the CPU device PM QoS used for the management of min and max
frequency constraints in cpufreq (and its users) with per-policy
frequency QoS to avoid problems with cpufreq policies covering
more then one CPU.

Namely, a cpufreq driver is registered with the subsys interface
which calls cpufreq_add_dev() for each CPU, starting from CPU0, so
currently the PM QoS notifiers are added to the first CPU in the
policy (i.e. CPU0 in the majority of cases).

In turn, when the cpufreq driver is unregistered, the subsys interface
doing that calls cpufreq_remove_dev() for each CPU, starting from CPU0,
and the PM QoS notifiers are only removed when cpufreq_remove_dev() is
called for the last CPU in the policy, say CPUx, which as a rule is
not CPU0 if the policy covers more than one CPU.  Then, the PM QoS
notifiers cannot be removed, because CPUx does not have them, and
they are still there in the device PM QoS notifiers list of CPU0,
which prevents new PM QoS notifiers from being registered for CPU0
on the next attempt to register the cpufreq driver.

The same issue occurs when the first CPU in the policy goes offline
before unregistering the driver.

After this change it does not matter which CPU is the policy CPU at
the driver registration time and whether or not it is online all the
time, because the frequency QoS is per policy and not per CPU.

Fixes: 67d874c3b2 ("cpufreq: Register notifiers with the PM QoS framework")
Reported-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Dmitry Osipenko <digetx@gmail.com>
Reported-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Diagnosed-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://lore.kernel.org/linux-pm/5ad2624194baa2f53acc1f1e627eb7684c577a19.1562210705.git.viresh.kumar@linaro.org/T/#md2d89e95906b8c91c15f582146173dce2e86e99f
Link: https://lore.kernel.org/linux-pm/20191017094612.6tbkwoq4harsjcqv@vireshk-i7/T/#m30d48cc23b9a80467fbaa16e30f90b3828a5a29b
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-10-21 02:05:21 +02:00
Viresh Kumar
d15ce41273 ACPI: cpufreq: Switch to QoS requests instead of cpufreq notifier
The cpufreq core now takes the min/max frequency constraints via QoS
requests and the CPUFREQ_ADJUST notifier shall get removed later on.

Switch over to using the QoS request for maximum frequency constraint
for acpi driver.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-08-28 11:21:53 +02:00
Brian Norris
a507a3065c ACPI / processor: Finish making acpi_processor_ppc_has_changed() void
Commit bca5f557dc "ACPI / processor: Make acpi_processor_ppc_has_changed()
void" changed one of the declarations of acpi_processor_ppc_has_changed()
to return void, but the !CPU_FREQ version still returns int. Let's return
void to be consistent.

Fixes: bca5f557dc "ACPI / processor: Make acpi_processor_ppc_has_changed() void"
Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-06-20 10:50:40 +02:00
Joao Martins
4d0f1ce695 xen/acpi: upload _PSD info for non Dom0 CPUs too
All uploaded PM data from non-dom0 CPUs takes the info from vCPU 0 and
changing only the acpi_id. For processors which P-state coordination type
is HW_ALL (0xFD) it is OK to upload bogus P-state dependency information
(_PSD), because Xen will ignore any cpufreq domains created for past CPUs.

Albeit for platforms which expose coordination types as SW_ANY or SW_ALL,
this will have some unintended side effects. Effectively, it will look at
the P-state domain existence and *if it already exists* it will skip the
acpi-cpufreq initialization and thus inherit the policy from the first CPU
in the cpufreq domain. This will finally lead to the original cpu not
changing target freq to P0 other than the first in the domain. Which will
make turbo boost not getting enabled (e.g. for 'performance' governor) for
all cpus.

This patch fixes that, by also evaluating _PSD when we enumerate all ACPI
processors and thus always uploading the correct info to Xen. We export
acpi_processor_get_psd() for that this purpose, but change signature
to not assume an existent of acpi_processor given that ACPI isn't creating
an acpi_processor for non-dom0 CPUs.

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2018-03-21 08:29:13 -04:00
Greg Kroah-Hartman
b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00
Rafael J. Wysocki
bca5f557dc ACPI / processor: Make acpi_processor_ppc_has_changed() void
The return value of acpi_processor_ppc_has_changed() is never used,
so make it void.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2016-11-21 14:35:42 +01:00
Rafael J. Wysocki
d0ea59e188 cpufreq: intel_pstate: Request P-states control from SMM if needed
Currently, intel_pstate is unable to control P-states on my
IvyBridge-based Acer Aspire S5, because they are controlled by SMM
on that machine by default and it is necessary to request OS control
of P-states from it via the SMI Command register exposed in the ACPI
FADT.  intel_pstate doesn't do that now, but acpi-cpufreq and other
cpufreq drivers for x86 platforms do.

Address this problem by making intel_pstate use the ACPI-defined
mechanism as well.  However, intel_pstate is not modular and it
doesn't need the module refcount tricks played by
acpi_processor_notify_smm(), so export the core of this function
to it as acpi_processor_pstate_control() and make it call that.
[The changes in processor_perflib.c related to this should not
make any functional difference for the acpi_processor_notify_smm()
users].

To be safe, only call acpi_processor_notify_smm() from intel_pstate
if ACPI _PPC support is enabled in it.

Suggested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
2016-11-17 22:47:47 +01:00
Sebastian Andrzej Siewior
64f3bf2f85 ACPI/processor: Convert to hotplug state machine
Install the callbacks via the state machine.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-acpi@vger.kernel.org
Cc: rt@linutronix.de
Cc: Len Brown <lenb@kernel.org>
Link: http://lkml.kernel.org/r/20160906170457.32393-12-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-09-19 21:44:29 +02:00
Rafael J. Wysocki
6149dffcb5 Merge branches 'acpi-processor', 'acpi-cppc', 'acpi-apei' and 'acpi-sleep'
* acpi-processor:
  ACPI: enable ACPI_PROCESSOR_IDLE on ARM64
  arm64: add support for ACPI Low Power Idle(LPI)
  drivers: firmware: psci: initialise idle states using ACPI LPI
  cpuidle: introduce CPU_PM_CPU_IDLE_ENTER macro for ARM{32, 64}
  arm64: cpuidle: drop __init section marker to arm_cpuidle_init
  ACPI / processor_idle: Add support for Low Power Idle(LPI) states
  ACPI / processor_idle: introduce ACPI_PROCESSOR_CSTATE

* acpi-cppc:
  mailbox: pcc: Add PCC request and free channel declarations
  ACPI / CPPC: Prevent cpc_desc_ptr points to the invalid data
  ACPI: CPPC: Return error if _CPC is invalid on a CPU

* acpi-apei:
  ACPI / APEI: Add Boot Error Record Table (BERT) support
  ACPI / einj: Make error paths more talkative
  ACPI / einj: Convert EINJ_PFX to proper pr_fmt

* acpi-sleep:
  ACPI: Execute _PTS before system reboot
2016-07-25 13:42:25 +02:00
Sudeep Holla
a36a7fecfe ACPI / processor_idle: Add support for Low Power Idle(LPI) states
ACPI 6.0 introduced an optional object _LPI that provides an alternate
method to describe Low Power Idle states. It defines the local power
states for each node in a hierarchical processor topology. The OSPM can
use _LPI object to select a local power state for each level of processor
hierarchy in the system. They used to produce a composite power state
request that is presented to the platform by the OSPM.

Since multiple processors affect the idle state for any non-leaf hierarchy
node, coordination of idle state requests between the processors is
required. ACPI supports two different coordination schemes: Platform
coordinated and  OS initiated.

This patch adds initial support for Platform coordination scheme of LPI.

Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-07-21 23:25:58 +02:00
Sudeep Holla
35ae713355 ACPI / processor_idle: introduce ACPI_PROCESSOR_CSTATE
ACPI 6.0 adds a new method to specify the CPU idle states(C-states)
called Low Power Idle(LPI) states. Since new architectures like ARM64
use only LPIs, introduce ACPI_PROCESSOR_CSTATE to encapsulate all the
code supporting the old style C-states(_CST).

This patch will help to extend the processor_idle module to support
LPI.

Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-07-21 23:24:35 +02:00
David Daney
fb7c2bae8a ACPI / processor: Add acpi_map_madt_entry()
Follow-on arm64 ACPI/NUMA patches need to map MADT entries very early
(before kmalloc is usable).

Add acpi_map_madt_entry() which, indirectly, uses
early_memremap()/early_memunmap() to access the table and parse out
the mpidr.  The existing implementation of map_madt_entry() is
modified to take a pointer to the MADT as a parameter and the callers
adjusted.

Signed-off-by: David Daney <david.daney@cavium.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-05-30 14:27:09 +02:00
Sudeep Holla
504997cf96 ACPI / sleep: move acpi_processor_sleep to sleep.c
acpi_processor_sleep is neither related nor used by CPUIdle framework.
It's used in system suspend/resume path as a syscore operation. It makes
more sense to move it to acpi/sleep.c where all the S-state transition
(a.k.a. Linux system suspend/hiberate) related code are present.

Also make it depend on CONFIG_ACPI_SYSTEM_POWER_STATES_SUPPORT so that
it's not compiled on architecture like ARM64 where S-states are not
yet defined in ACPI.

Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-02-22 00:53:56 +01:00
Sudeep Holla
db62fda318 ACPI / processor : add support for ACPI0010 processor container
ACPI 6.0 adds support for optional processor container device which may
contain child objects that are either processor devices or other processor
containers. This allows representing hierarchical processor topologies.

It is declared using the _HID of ACPI0010. It is an abstract container
used to represent CPU topology and should not be used to hotplug
purposes.

If no matching handler is found for a device in acpi_scan_attach_handler,
acpi_bus_attach does a default enumeration for those devices with valid
HID in the acpi namespace. This patch adds a scan handler for these ACPI
processor containers to avoid default that enumeration and ensures the
platform devices are not created for them.

Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-02-22 00:53:56 +01:00
Ashwin Chaugule
4f2f757351 CPPC: Probe for CPPC tables for each ACPI Processor object
For each detected ACPI Processor object (ACPI0007), search its
device handle for CPPC specific tables (i.e. _CPC) and extract
CPU specific performance capabilities.

Signed-off-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
Reviewed-by: Al Stone <al.stone@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-10-12 23:08:04 +02:00
Rafael J. Wysocki
4ffe18c255 Merge branch 'pm-cpufreq'
* pm-cpufreq: (53 commits)
  cpufreq: speedstep-lib: Use monotonic clock
  cpufreq: powernv: Increase the verbosity of OCC console messages
  cpufreq: sfi: use kmemdup rather than duplicating its implementation
  cpufreq: drop !cpufreq_driver check from cpufreq_parse_governor()
  cpufreq: rename cpufreq_real_policy as cpufreq_user_policy
  cpufreq: remove redundant 'policy' field from user_policy
  cpufreq: remove redundant 'governor' field from user_policy
  cpufreq: update user_policy.* on success
  cpufreq: use memcpy() to copy policy
  cpufreq: remove redundant CPUFREQ_INCOMPATIBLE notifier event
  cpufreq: mediatek: Add MT8173 cpufreq driver
  dt-bindings: mediatek: Add MT8173 CPU DVFS clock bindings
  intel_pstate: append more Oracle OEM table id to vendor bypass list
  intel_pstate: Add SKY-S support
  intel_pstate: Fix possible overflow complained by Coverity
  cpufreq: Correct a freq check in cpufreq_set_policy()
  cpufreq: Lock CPU online/offline in cpufreq_register_driver()
  cpufreq: Replace recover_policy with new_policy in cpufreq_online()
  cpufreq: Separate CPU device registration from CPU online
  cpufreq: powernv: Restore cpu frequency to policy->cur on unthrottling
  ...
2015-09-01 15:52:35 +02:00
Ashwin Chaugule
5f05586c60 ACPI: Decouple ACPI idle and ACPI processor drivers
This patch introduces a new Kconfig symbol, ACPI_PROCESSOR_IDLE,
which is auto selected by architectures which support the ACPI
based C states for CPU Idle management.

The processor_idle driver in its present form contains declarations
specific to X86 and IA64. Since there are no reasonable defaults
for other architectures e.g. ARM64, the driver is selected only for
X86 or IA64.

This helps in decoupling the ACPI processor_driver from the ACPI
processor_idle driver which is useful for the upcoming alternative
patchwork for controlling CPU Performance (CPPC) and CPU Idle (LPI).

Signed-off-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-08-25 03:25:47 +02:00
Ashwin Chaugule
239708a3af ACPI: Split out ACPI PSS from ACPI Processor driver
The ACPI processor driver is currently tied too closely
to the ACPI P-states (PSS) and other related constructs
for controlling CPU performance.

The newer ACPI specification (v5.1 onwards) introduces
alternative methods to PSS. These new mechanisms are
described within each ACPI Processor object and so they
need to be scanned whenever a new Processor object is detected.
This patch introduces a new Kconfig symbol to allow for
finer configurability among the two options for controlling
performance states. There is no change in functionality and
the option is auto-selected by the architectures which support it.

A future commit will introduce support for CPPC: A newer method of
controlling CPU performance. The OS is not expected to support
CPPC and PSS at the same time, so the Kconfig option lets us make
the two mutually exclusive at compile time.

Signed-off-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-08-25 03:25:47 +02:00
Rafael J. Wysocki
b2f8dc4ce6 ACPI / processor: Drop an unused argument of a cleanup routine
acpi_processor_unregister_performance() actually doesn't use its
first argument, so drop it and update the callers accordingly.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2015-07-22 22:11:16 +02:00
Catalin Marinas
828aef376d ACPI / processor: Introduce phys_cpuid_t for CPU hardware ID
CPU hardware ID (phys_id) is defined as u32 in structure acpi_processor,
but phys_id is used as int in acpi processor driver, so it will lead to
some inconsistence for the drivers.

Furthermore, to cater for ACPI arch ports that implement 64 bits CPU
ids a generic CPU physical id type is required.

So introduce typedef u32 phys_cpuid_t in a common file, and introduce
a macro PHYS_CPUID_INVALID as (phys_cpuid_t)(-1) if it's not defined
by other archs, this will solve the inconsistence in acpi processor driver,
and will prepare for the ACPI on ARM64 for the 64 bit CPU hardware ID
in the following patch.

CC: Rafael J Wysocki <rjw@rjwysocki.net>
Suggested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Grant Likely <grant.likely@linaro.org>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
[hj: reworked cpu physid map return codes]
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2015-03-26 15:12:51 +00:00
Hanjun Guo
af8f3f514d ACPI / processor: Convert apic_id to phys_id to make it arch agnostic
apic_id in MADT table is the CPU hardware id which identify
it self in the system for x86 and ia64, OSPM will use it for
SMP init to map APIC ID to logical cpu number in the early
boot, when the DSDT/SSDT (ACPI namespace) is scanned later, the
ACPI processor driver is probed and the driver will use acpi_id
in DSDT to get the apic_id, then map to the logical cpu number
which is needed by the processor driver.

Before ACPI 5.0, only x86 and ia64 were supported in ACPI spec,
so apic_id is used both in arch code and ACPI core which is
pretty fine. Since ACPI 5.0, ARM is supported by ACPI and
APIC is not available on ARM, this will confuse people when
apic_id is both used by x86 and ARM in one function.

So convert apic_id to phys_id (which is the original meaning)
in ACPI processor dirver to make it arch agnostic, but leave the
arch dependent code unchanged, no functional change.

Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-01-05 23:32:42 +01:00
Sudeep Holla
bccac16eea ACPI / processor: remove unused variabled from acpi_processor_power structure
Few elements in the acpi_processor_power structure are unused. It could
be remnant in the header missed while the code got removed from the
corresponding driver file.

This patch removes those unused variables in the structure declaration.

Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-11-25 23:43:52 +01:00
Hanjun Guo
24119a8829 ACPI / processor: Update the comments in processor.h
In commit 46ba51e (ACPI / processor: Introduce ARCH_MIGHT_HAVE_ACPI_PDC),
acpi_processor_set_pdc() was moved to processor_pdc.c, so update
the comments accordingly.

Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-11-11 23:47:25 +01:00
Fabian Frederick
92c4d2ad3c ACPI / processor replace __attribute__((packed)) by __packed
This patch fixes checkpatch warnings:

"WARNING: __packed is preferred over __attribute__((packed))"

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-06-17 14:00:15 +02:00
Rafael J. Wysocki
34411a69a4 ACPI / processor: Do not request ACPI cpufreq module directly
Function acpi_processor_load_module() used by the ACPI processor
driver can only really work if the acpi-cpufreq module is available
when acpi_processor_start() is executed which usually is not the case
for systems loading the processor driver module from an initramfs.

Moreover, that used to be a hackish workaround for module autoloading
issues, but udev loads acpi-cpufreq just fine nowadays, so that
function isn't really necessary any more.  For this reason, drop
acpi_processor_load_module() entirely.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-30 00:00:30 +01:00
Jiang Liu
ca9f62ac78 ACPI / processor: Introduce apic_id in struct processor to save parsed APIC id
For cpu hot add, we evaluate _MAT or parse MADT twice to get APIC id,
here is the code logic:
acpi_processor_add()
	acpi_processor_get_info()
		acpi_get_cpuid() will evaluate _MAT or parse MADT;
	acpi_processor_hotadd_init()
		acpi_map_lsapic() will evaluate _MAT again;

This can be done more effectively, this patch introduces apic_id in struct
processor to save parsed APIC id, and then we can use it and remove the
duplicated _MAT evaluation.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-09-24 01:39:39 +02:00
Rafael J. Wysocki
ac212b6980 ACPI / processor: Use common hotplug infrastructure
Split the ACPI processor driver into two parts, one that is
non-modular, resides in the ACPI core and handles the enumeration
and hotplug of processors and one that implements the rest of the
existing processor driver functionality.

The non-modular part uses an ACPI scan handler object to enumerate
processors on the basis of information provided by the ACPI namespace
and to hook up with the common ACPI hotplug infrastructure.  It also
populates the ACPI handle of each processor device having a
corresponding object in the ACPI namespace, which allows the driver
proper to bind to those devices, and makes the driver bind to them
if it is readily available (i.e. loaded) when the scan handler's
.attach() routine is running.

There are a few reasons to make this change.

First, switching the ACPI processor driver to using the common ACPI
hotplug infrastructure reduces code duplication and size considerably,
even though a new file is created along with a header comment etc.

Second, since the common hotplug code attempts to offline devices
before starting the (non-reversible) removal procedure, it will abort
(and possibly roll back) hot-remove operations involving processors
if cpu_down() returns an error code for one of them instead of
continuing them blindly (if /sys/firmware/acpi/hotplug/force_remove
is unset).  That is a more desirable behavior than what the current
code does.

Finally, the separation of the scan/hotplug part from the driver
proper makes it possible to simplify the driver's .remove() routine,
because it doesn't need to worry about the possible cleanup related
to processor removal any more (the scan/hotplug part is responsible
for that now) and can handle device removal and driver removal
symmetricaly (i.e. as appropriate).

Some user-visible changes in sysfs are made (for example, the
'sysdev' link from the ACPI device node to the processor device's
directory is gone and a 'physical_node' link is present instead
and a corresponding 'firmware_node' is present in the processor
device's directory, the processor driver is now visible under
/sys/bus/cpu/drivers/ and bound to the processor device), but
that shouldn't affect the functionality that users care about
(frequency scaling, C-states and thermal management).

Tested on my venerable Toshiba Portege R500.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Toshi Kani <toshi.kani@hp.com>
2013-05-12 14:14:32 +02:00
Rafael J. Wysocki
0a3b15ac3c ACPI / PM: Move processor suspend/resume to syscore_ops
The system suspend routine of the ACPI processor driver saves
the BUS_MASTER_RLD register and its resume routine restores it.
However, there can be only one such register in the system and it
really should be saved after non-boot CPUs have been offlined and
restored before they are put back online during resume.

For this reason, move the saving and restoration of BUS_MASTER_RLD
to syscore suspend and syscore resume, respectively, and drop the no
longer necessary suspend/resume callbacks from the ACPI processor
driver.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-05-12 14:03:14 +02:00
Konrad Rzeszutek Wilk
c705c78c0d acpi: Export the acpi_processor_get_performance_info
The git commit d5aaffa9dd
(cpufreq: handle cpufreq being disabled for all exported function)
tightens the cpufreq API by returning errors when disable_cpufreq()
had been called.

The problem we are hitting is that the module xen-acpi-processor which
uses the ACPI's functions: acpi_processor_register_performance,
acpi_processor_preregister_performance, and acpi_processor_notify_smm
fails at acpi_processor_register_performance with -22.

Note that earlier during bootup in arch/x86/xen/setup.c there is also
an call to cpufreq's API: disable_cpufreq().

This is b/c we want the Linux kernel to parse the ACPI data, but leave
the cpufreq decisions to the hypervisor.

In v3.9 all the checks that d5aaffa9dd
added are now hit and the calls to cpufreq_register_notifier will now
fail. This means that acpi_processor_ppc_init ends up printing:

"Warning: Processor Platform Limit not supported"

and the acpi_processor_ppc_status is not set.

The repercussions of that is that the call to
acpi_processor_register_performance fails right away at:

	if (!(acpi_processor_ppc_status & PPC_REGISTERED))

and we don't progress any further on parsing and extracting the _P*
objects.

The only reason the Xen code called that function was b/c it was
exported and the only way to gather the P-states. But we can also
just make acpi_processor_get_performance_info be exported and not
use acpi_processor_register_performance. This patch does so.

Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-03-06 10:00:34 -05:00
Daniel Lezcano
3d339dcbb5 cpuidle / ACPI : move cpuidle_device field out of the acpi_processor_power structure
Currently we have the cpuidle_device field in the acpi_processor_power structure.
This adds a dependency between processor.h and cpuidle.h

Although it is not a real problem, removing this dependency has the benefit of
separating a bit more the cpuidle code from the rest of the acpi code.
Also, the compilation should be a bit improved because we do no longer
include cpuidle.h in processor.h. The preprocessor was generating 30418 loc
and with this patch it generates 30256 loc for processor_thermal.c, a file
which is not concerned at all by cpuidle, like processor_perflib.c and
processor_throttling.c.

That may sound ridiculous, but "small streams make big rivers" :P

This patch moves this field into a static global per cpu variable like what is
done in the intel_idle driver.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-09-17 23:01:56 +02:00
Daniel Lezcano
38a991b625 ACPI / processor: remove unused function parameter
The 'device' parameter is not used neither in acpi_processor_power_init
and acpi_processor_power_exit. This patch removes it.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-09-15 22:42:54 +02:00
Daniel Lezcano
c59687f846 cpuidle / ACPI : remove power from acpi_processor_cx structure
Remove the unused power field from struct struct acpi_processor_cx.

[rjw: Modified changelog.]

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-09-05 15:13:48 +02:00
Rafael J. Wysocki
6148d38b37 Merge branch 'pm-acpi'
* pm-acpi: (24 commits)
  olpc-xo15-sci: Use struct dev_pm_ops for power management
  ACPI / PM: Drop PM callbacks from the ACPI bus type
  ACPI / PM: Drop legacy driver PM callbacks that are not used any more
  ACPI / PM: Do not execute legacy driver PM callbacks
  acpi_power_meter: Use struct dev_pm_ops for power management
  fujitsu-tablet: Use struct dev_pm_ops for power management
  classmate-laptop: Use struct dev_pm_ops for power management
  xo15-ebook: Use struct dev_pm_ops for power management
  toshiba_bluetooth: Use struct dev_pm_ops for power management
  panasonic-laptop: Use struct dev_pm_ops for power management
  sony-laptop: Use struct dev_pm_ops for power management
  hp_accel: Use struct dev_pm_ops for power management
  toshiba_acpi: Use struct dev_pm_ops for power management
  ACPI: Use struct dev_pm_ops for power management in the SBS driver
  ACPI: Use struct dev_pm_ops for power management in the power driver
  ACPI: Use struct dev_pm_ops for power management in the button driver
  ACPI: Use struct dev_pm_ops for power management in the battery driver
  ACPI: Use struct dev_pm_ops for power management in the AC driver
  ACPI: Use struct dev_pm_ops for power management in processor driver
  ACPI: Use struct dev_pm_ops for power management in the thermal driver
  ...
2012-07-19 00:03:35 +02:00
Daniel Lezcano
aa713cc3b2 cpuilde / ACPI: remove time from acpi_processor_cx structure
Remove the time field as it is not used.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-07-17 22:16:04 +02:00
Daniel Lezcano
53b70951d9 cpuidle / ACPI: remove usage from acpi_processor_cx structure
Remove the usage field as it is not used.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-07-17 22:16:00 +02:00
Daniel Lezcano
64d45f07b4 cpuidle / ACPI : remove latency_ticks from acpi_processor_cx structure
Remove the latency_ticks field as it is not used.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-07-17 22:15:24 +02:00
Rafael J. Wysocki
e8110b64af ACPI: Use struct dev_pm_ops for power management in processor driver
Make the ACPI processor driver define its PM callbacks through
a struct dev_pm_ops object rather than by using legacy PM hooks
in struct acpi_device_ops.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-07-01 13:31:00 +02:00
Rafael J. Wysocki
17621e11fd ACPI / PM: Drop pm_message_t argument from device suspend callback
None of the drivers implementing the ACPI device suspend callback
uses the pm_message_t argument of it, so this argument may be dropped
entirely from that callback.  This will simplify switching the ACPI
bus type to PM handling based on struct dev_pm_ops.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-07-01 13:30:58 +02:00
Greg Kroah-Hartman
bd1d462e13 Merge 3.3-rc2 into the driver-core-next branch.
This was done to resolve a merge and build problem with the
drivers/acpi/processor_driver.c file.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-02-02 11:24:44 -08:00
Andi Kleen
9061e0e167 ACPI: Load acpi-cpufreq from processor driver automatically
The only left over hole in automatic cpufreq driver loading was the loading
of ACPI cpufreq. This driver should be loaded when ACPI supports a _PDC
method and the CPU vendor wants to use acpi cpufreq.

Simply add a request module call to the acpi processor core driver
when this is true. This seems like the simplest solution for this.

Cc: Len Brown <lenb@kernel.org>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Renninger <trenn@suse.de>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2012-01-26 16:48:12 -08:00
Thomas Renninger
99b7250844 ACPI processor hotplug: Delay acpi_processor_start() call for hotplugged cores
Delay the setting up of features (cpuidle, throttling by calling
acpi_processor_start()) to the time when the hotplugged
core got onlined the first time and got fully
initialized.

Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>
2012-01-19 21:26:32 -05:00
Deepthi Dharwar
46bcfad7a8 cpuidle: Single/Global registration of idle states
This patch makes the cpuidle_states structure global (single copy)
instead of per-cpu. The statistics needed on per-cpu basis
by the governor are kept per-cpu. This simplifies the cpuidle
subsystem as state registration is done by single cpu only.
Having single copy of cpuidle_states saves memory. Rare case
of asymmetric C-states can be handled within the cpuidle driver
and architectures such as POWER do not have asymmetric C-states.

Having single/global registration of all the idle states,
dynamic C-state transitions on x86 are handled by
the boot cpu. Here, the boot cpu  would disable all the devices,
re-populate the states and later enable all the devices,
irrespective of the cpu that would receive the notification first.

Reference:
https://lkml.org/lkml/2011/4/25/83

Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: Trinabh Gupta <g.trinabh@gmail.com>
Tested-by: Jean Pihet <j-pihet@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2011-11-06 21:13:58 -05:00
Vasiliy Kulikov
9c8b04be44 ACPI: constify ops structs
Structs battery_file, acpi_dock_ops, file_operations,
thermal_cooling_device_ops, thermal_zone_device_ops, kernel_param_ops
are not changed in runtime.  It is safe to make them const.
register_hotplug_dock_device() was altered to take const "ops" argument
to respect acpi_dock_ops' const notion.

Signed-off-by: Vasiliy Kulikov <segoon@openwall.com>
Acked-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2011-07-16 18:36:17 -04:00