cpufreq: pcc: Fix the potentinal scheduling delays in target_index()

pcc_cpufreq_target():
cpufreq_freq_transition_begin();
spin_lock(&pcc_lock);
[critical section]
cpufreq_freq_transition_end();
spin_unlock(&pcc_lock);

Above code has a performance issue, consider that Task0 executes
'cpufreq_freq_transition_end()' to wake Task1 and preempted imediatedly
without releasing 'pcc_lock', then Task1 needs to wait for Task0 to
release 'pcc_lock'. In the worst case, this locking order can result in
Task1 wasting two scheduling rounds before it can enter the critical
section.

Signed-off-by: Liao Chang <liaochang1@huawei.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: pcc-cpufreq: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Yangtao Li <frank.li@vivo.com>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: ACPI: Prevent a warning when another frequency driver is loaded

The recent change to use platform devices to load ACPI PPC and PCC
drivers caused that a misleading warning is reported when a respective
module cannot be loaded because another CPU frequency driver is already
registered:

kernel: acpi-cpufreq: probe of acpi-cpufreq failed with error -17

Address it by changing the return code in acpi-cpufreq and pcc-cpufreq
for this case from -EEXIST to -ENODEV which silences the warning in
call_driver_probe().

The change has also a benefit for users of init_module() as this return
code is propagated out from the syscall. The previous -EEXIST code made
the callers, such as kmod, wrongly believe that the module was already
loaded instead of that it failed to load.

Fixes: 691a63712347 ("ACPI: cpufreq: Use platform devices to load ACPI PPC and PCC drivers")
Reported-by: Kevin Locke <kevin@kevinlocke.name>
Link: https://lore.kernel.org/lkml/ZFreh8SDMX67EaB6@kevinlocke.name/
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Tested-by: Kevin Locke <kevin@kevinlocke.name>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Merge tag 'devicetree-for-6.4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux

Pull more devicetree updates from Rob Herring:

- First part of DT header detangling dropping cpu.h from of_device.h
and replacing some includes with forward declarations. A handful of
drivers needed some adjustment to their includes as a result.

- Refactor of_device.h to be used by bus drivers rather than various
device drivers. This moves non-bus related functions out of
of_device.h. The end goal is for of_platform.h and of_device.h to
stop including each other.

- Refactor open coded parsing of "ranges" in some bus drivers to use DT
address parsing functions

- Add some new address parsing functions of_property_read_reg(),
of_range_count(), and of_range_to_resource() in preparation to
convert more open coded parsing of DT addresses to use them.

- Treewide clean-ups to use of_property_read_bool() and
of_property_present() as appropriate. The ones here are the ones that
didn't get picked up elsewhere.

* tag 'devicetree-for-6.4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: (34 commits)
bus: tegra-gmi: Replace of_platform.h with explicit includes
hte: Use of_property_present() for testing DT property presence
w1: w1-gpio: Use of_property_read_bool() for boolean properties
virt: fsl: Use of_property_present() for testing DT property presence
soc: fsl: Use of_property_present() for testing DT property presence
sbus: display7seg: Use of_property_read_bool() for boolean properties
sparc: Use of_property_read_bool() for boolean properties
sparc: Use of_property_present() for testing DT property presence
bus: mvebu-mbus: Remove open coded "ranges" parsing
of/address: Add of_property_read_reg() helper
of/address: Add of_range_count() helper
of/address: Add support for 3 address cell bus
of/address: Add of_range_to_resource() helper
of: unittest: Add bus address range parsing tests
of: Drop cpu.h include from of_device.h
OPP: Adjust includes to remove of_device.h
irqchip: loongson-eiointc: Add explicit include for cpuhotplug.h
cpuidle: Adjust includes to remove of_device.h
cpufreq: sun50i: Add explicit include for cpu.h
cpufreq: Adjust includes to remove of_device.h
...

ACPI: cpufreq: Use platform devices to load ACPI PPC and PCC drivers

The acpi-cpufreq and pcc-cpufreq drivers are loaded through per-CPU
module aliases. This can result in many unnecessary load requests during
boot if another frequency module, such as intel_pstate, is already
active. For instance, on a typical Intel system, one can observe that
udev makes 2x#CPUs attempts to insert acpi_cpufreq and 1x#CPUs attempts
for pcc_cpufreq. All these tries then fail if another frequency module
is already registered.

In the worst case, without the recent fix in commit 0254127ab977e
("module: Don't wait for GOING modules"), these module loads occupied
all udev workers and had their initialization attempts ran sequentially.
Resolving all these loads then on some larger machines took too long,
prevented other hardware from getting its drivers initialized and
resulted in a failed boot. Discussion over these duplicate module
requests ended up with a conclusion that only one load attempt should be
ideally made.

Both acpi-cpufreq and pcc-cpufreq drivers use platform firmware controls
which are defined by ACPI. It is possible to treat these interfaces as
platform devices.

The patch extends the ACPI parsing logic to check the ACPI namespace if
the PPC or PCC interface is present and creates a virtual platform
device for each if it is available. The acpi-cpufreq and pcc-cpufreq
drivers are then updated to map to these devices.

This allows to try loading acpi-cpufreq and pcc-cpufreq only once during
boot and only if a given interface is available in the firmware.

Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
[ rjw: whitespace and error message log level adjustments, subject edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: pcc-cpufreq: Mark sometimes used ID structs as __maybe_unused

Not used when MODULE is not defined.

Fixes the following W=1 kernel build warning(s):

drivers/cpufreq/pcc-cpufreq.c:619:36: warning: ‘processor_device_ids’ defined but not used [-Wunused-const-variable=]
619 | static const struct acpi_device_id processor_device_ids[] = {
| ^~~~~~~~~~~~~~~~~~~~

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Merge tag 'pm-5.6-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull more power manadement updates from Rafael Wysocki:
"Prevent cpufreq from creating excessively large stack frames and fix
the handling of devices deleted during system-wide resume in the PM
core (Rafael Wysocki), revert a problematic commit affecting the
cpupower utility and correct its man page (Thomas Renninger,
Brahadambal Srinivasan), and improve the intel_pstate_tracer utility
(Doug Smythies)"

* tag 'pm-5.6-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
tools/power/x86/intel_pstate_tracer: change several graphs to autoscale y-axis
tools/power/x86/intel_pstate_tracer: changes for python 3 compatibility
Correction to manpage of cpupower
cpufreq: Avoid creating excessively large stack frames
PM: core: Fix handling of devices deleted during system-wide resume
cpupower: Revert library ABI changes from commit ae2917093fb60bdc1ed3e

cpufreq: Avoid creating excessively large stack frames

In the process of modifying a cpufreq policy, the cpufreq core makes
a copy of it including all of the internals which is stored on the
CPU stack. Because struct cpufreq_policy is relatively large, this
may cause the size of the stack frame to exceed the 2 KB limit and
so the GCC complains when -Wframe-larger-than= is used.

In fact, it is not necessary to copy the entire policy structure
in order to modify it, however.

First, because cpufreq_set_policy() obtains the min and max policy
limits from frequency QoS now, it is not necessary to pass the limits
to it from the callers. The only things that need to be passed to it
from there are the new governor pointer or (if there is a built-in
governor in the driver) the "policy" value representing the governor
choice. They both can be passed as individual arguments, though, so
make cpufreq_set_policy() take them this way and rework its callers
accordingly. This avoids making copies of cpufreq policies in the
callers of cpufreq_set_policy().

Second, cpufreq_set_policy() still needs to pass the new policy
data to the ->verify() callback of the cpufreq driver whose task
is to sanitize the min and max policy limits. It still does not
need to make a full copy of struct cpufreq_policy for this purpose,
but it needs to pass a few items from it to the driver in case they
are needed (different drivers have different needs in that respect
and all of them have to be covered). For this reason, introduce
struct cpufreq_policy_data to hold copies of the members of
struct cpufreq_policy used by the existing ->verify() driver
callbacks and pass a pointer to a temporary structure of that
type to ->verify() (instead of passing a pointer to full struct
cpufreq_policy to it).

While at it, notice that intel_pstate and longrun don't really need
to verify the "policy" value in struct cpufreq_policy, so drop those
check from them to avoid copying "policy" into struct
cpufreq_policy_data (which allows it to be slightly smaller).

Also while at it fix up white space in a couple of places and make
cpufreq_set_policy() static (as it can be so).

Fixes: 3000ce3c52f8 ("cpufreq: Use per-policy frequency QoS")
Link: https://lore.kernel.org/linux-pm/CAMuHMdX6-jb1W8uC2_237m8ctCpsnGp=JCxqt8pCWVqNXHmkVg@mail.gmail.com
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

remove ioremap_nocache and devm_ioremap_nocache

ioremap has provided non-cached semantics by default since the Linux 2.6
days, so remove the additional ioremap_nocache interface.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>

cpufreq: pcc-cpufreq: Fail initialization if driver cannot be registered

Make pcc_cpufreq_init() return error codes when the driver cannot be
registered. Otherwise the driver can shows up loaded via lsmod even
though it failed initialization. This is confusing to the user.

Signed-off-by: David Arcari <darcari@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: pcc-cpufreq: remove unneeded semicolon

The semicolon is unneeded, so remove it.

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

Merge back cpufreq material for 4.19.

cpufreq: intel_pstate: Register when ACPI PCCH is present

Currently, intel_pstate doesn't register if _PSS is not present on
HP Proliant systems, because it expects the firmware to take over
CPU performance scaling in that case. However, if ACPI PCCH is
present, the firmware expects the kernel to use it for CPU
performance scaling and the pcc-cpufreq driver is loaded for that.

Unfortunately, the firmware interface used by that driver is not
scalable for fundamental reasons, so pcc-cpufreq is way suboptimal
on systems with more than just a few CPUs. In fact, it is better to
avoid using it at all.

For this reason, modify intel_pstate to look for ACPI PCCH if _PSS
is not present and register if it is there. Also prevent the
pcc-cpufreq driver from trying to initialize itself if intel_pstate
has been registered already.

Fixes: fbbcdc0744da (intel_pstate: skip the driver if ACPI has power mgmt option)
Reported-by: Andreas Herrmann <aherrmann@suse.com>
Reviewed-by: Andreas Herrmann <aherrmann@suse.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Tested-by: Andreas Herrmann <aherrmann@suse.com>
Cc: 4.16+ <stable@vger.kernel.org> # 4.16+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: pcc-cpufreq: Disable dynamic scaling on many-CPU systems

The firmware interface used by the pcc-cpufreq driver is
fundamentally not scalable and using it for dynamic CPU performance
scaling on systems with many CPUs leads to degraded performance.

For this reason, disable dynamic CPU performance scaling on systems
with pcc-cpufreq where the number of CPUs present at the driver init
time is greater than 4. Also make the driver print corresponding
complaints to the kernel log.

Reported-by: Andreas Herrmann <aherrmann@suse.com>
Tested-by: Andreas Herrmann <aherrmann@suse.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Revert "cpufreq: pcc-cpufreq: update default value of cpuinfo_transition_latency"

This reverts commit 790d849bf811a8ab5d4cd2cce0f6fda92f6aebf2.

Using a v4.7-rc7 kernel on a HP ProLiant triggered following messages

pcc-cpufreq: (v1.10.00) driver loaded with frequency limits: 1200 MHz, 2800 MHz
cpufreq: ondemand governor failed, too long transition latency of HW, fallback to performance governor

The last line was shown for each CPU in the system.
Testing v4.5 (where commit 790d849b was integrated) triggered
similar messages. Same behaviour on a 2nd HP Proliant system.

So commit 790d849bf (cpufreq: pcc-cpufreq: update default value of
cpuinfo_transition_latency) causes the system to use performance
governor which, I guess, was not the intention of the patch.

Enabling debug output in pcc-cpufreq provides following verbose output:

pcc-cpufreq: (v1.10.00) driver loaded with frequency limits: 1200 MHz, 2800 MHz
pcc_get_offset: for CPU 0: pcc_cpu_data input_offset: 0x44, pcc_cpu_data output_offset: 0x48
init: policy->max is 2800000, policy->min is 1200000
get: get_freq for CPU 0
get: SUCCESS: (virtual) output_offset for cpu 0 is 0xffffc9000d7c0048, contains a value of: 0xff06. Speed is: 168000 MHz
cpufreq: ondemand governor failed, too long transition latency of HW, fallback to performance governor
target: CPU 0 should go to target freq: 2800000 (virtual) input_offset is 0xffffc9000d7c0044
target: was SUCCESSFUL for cpu 0

I am asking to revert 790d849bf to re-enable usage of ondemand
governor with pcc-cpufreq.

Fixes: 790d849bf (cpufreq: pcc-cpufreq: update default value of cpuinfo_transition_latency)
CC: <stable@vger.kernel.org> # 4.5+
Signed-off-by: Andreas Herrmann <aherrmann@suse.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: pcc-cpufreq: Fix doorbell.access_width

Commit 920de6ebfab8 (ACPICA: Hardware: Enhance
acpi_hw_validate_register() with access_width/bit_offset awareness)
apparently exposed a latent bug, doorbell.access_width is initialized
to 64, but per Lv Zheng, it should be 4, and indeed, making that
change does bring pcc-cpufreq back to life.

Fixes: 920de6ebfab8 (ACPICA: Hardware: Enhance acpi_hw_validate_register() with access_width/bit_offset awareness)
Suggested-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: pcc-cpufreq: update default value of cpuinfo_transition_latency

The cpufreq documentation specifies

policy->cpuinfo.transition_latency the time it takes on this CPU to
switch between two frequencies in
nanoseconds (if appropriate, else
specify CPUFREQ_ETERNAL)

currently pcc-cpufreq does not expose the value and sets it to zero. I
changed the pcc-cpufreq driver and it's documentation to conform to the
default value specified in Documentation/cpu-freq/cpu-drivers.txt

Signed-off-by: Jacob Tanenbaum <jtanenba@redhat.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: pcc: Enable autoload of pcc-cpufreq for ACPI processors

The pcc-cpufreq driver is not automatically loaded on systems where
the platform's power management setting requires this driver.
Instead, on those systems no CPU frequency driver is registered and
active.

Make the autoloading matching criteria for loading the pcc-cpufreq
driver the same as done in acpi-cpufreq by commit c655affbd524d01
("ACPI / cpufreq: Add ACPI processor device IDs to acpi-cpufreq").

x86 CPU frequency drivers are now typically autoloaded by specifying
MODULE_DEVICE_TABLE entries and x86cpu model specific matching.
But pcc-cpufreq was omitted when acpi-cpufreq and other drivers were
changed to use this approach.

Both acpi-cpufreq and pcc-cpufreq depend on a distinct and mutually
exclusive set of ACPI methods which are not directly tied to specific
processor model numbers. Both of these drivers have init routines
which look for their required ACPI methods. As a result, only the
appropriate driver registers as the cpu frequency driver and the other
one ends up being unloaded.

Tested on various systems where acpi-cpufreq, intel_pstate, and
pcc-cpufreq are the expected cpu frequency drivers.

Signed-off-by: Lenny Szubowicz <lszubowi@redhat.com>
Signed-off-by: Joseph Szczypek <joseph.szczypek@hp.com>
Reported-by: Trinh Dao <trinh.dao@hp.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: pcc-cpufreq: Fix wait_event() under spinlock

Fix the following bug introduced by commit 8fec051eea73 (cpufreq:
Convert existing drivers to use cpufreq_freq_transition_{begin|end})
that forgot to move the spin_lock() in pcc_cpufreq_target() past
cpufreq_freq_transition_begin() which calls wait_event():

BUG: sleeping function called from invalid context at drivers/cpufreq/cpufreq.c:370
in_atomic(): 1, irqs_disabled(): 0, pid: 2636, name: modprobe
Preemption disabled at:[<ffffffffa04d74d7>] pcc_cpufreq_target+0x27/0x200 [pcc_cpufreq]
[ 51.025044]
CPU: 57 PID: 2636 Comm: modprobe Tainted: G E 3.17.0-default #7
Hardware name: Hewlett-Packard ProLiant DL980 G7, BIOS P66 07/07/2010
00000000ffffffff ffff88026c46b828 ffffffff81589dbd 0000000000000000
ffff880037978090 ffff88026c46b848 ffffffff8108e1df ffff880037978090
0000000000000000 ffff88026c46b878 ffffffff8108e298 ffff88026d73ec00
Call Trace:
[<ffffffff81589dbd>] dump_stack+0x4d/0x90
[<ffffffff8108e1df>] ___might_sleep+0x10f/0x180
[<ffffffff8108e298>] __might_sleep+0x48/0xd0
[<ffffffff8145b905>] cpufreq_freq_transition_begin+0x75/0x140 drivers/cpufreq/cpufreq.c:370 wait_event(policy->transition_wait, !policy->transition_ongoing);
[<ffffffff8108fc99>] ? preempt_count_add+0xb9/0xc0
[<ffffffffa04d7513>] pcc_cpufreq_target+0x63/0x200 [pcc_cpufreq] drivers/cpufreq/pcc-cpufreq.c:207 spin_lock(&pcc_lock);
[<ffffffff810e0d0f>] ? update_ts_time_stats+0x7f/0xb0
[<ffffffff8145be55>] __cpufreq_driver_target+0x85/0x170
[<ffffffff8145e4c8>] od_check_cpu+0xa8/0xb0
[<ffffffff8145ef10>] dbs_check_cpu+0x180/0x1d0
[<ffffffff8145f310>] cpufreq_governor_dbs+0x3b0/0x720
[<ffffffff8145ebe3>] od_cpufreq_governor_dbs+0x33/0xe0
[<ffffffff814593d9>] __cpufreq_governor+0xa9/0x210
[<ffffffff81459fb2>] cpufreq_set_policy+0x1e2/0x2e0
[<ffffffff8145a6cc>] cpufreq_init_policy+0x8c/0x110
[<ffffffff8145c9a0>] ? cpufreq_update_policy+0x1b0/0x1b0
[<ffffffff8108fb99>] ? preempt_count_sub+0xb9/0x100
[<ffffffff8145c6c6>] __cpufreq_add_dev+0x596/0x6b0
[<ffffffffa016c608>] ? pcc_cpufreq_probe+0x4b4/0x4b4 [pcc_cpufreq]
[<ffffffff8145c7ee>] cpufreq_add_dev+0xe/0x10
[<ffffffff81408e81>] subsys_interface_register+0xc1/0xf0
[<ffffffff8108fb99>] ? preempt_count_sub+0xb9/0x100
[<ffffffff8145b3d7>] cpufreq_register_driver+0x117/0x2a0
[<ffffffffa016c65d>] pcc_cpufreq_init+0x55/0x9f8 [pcc_cpufreq]
[<ffffffffa016c608>] ? pcc_cpufreq_probe+0x4b4/0x4b4 [pcc_cpufreq]
[<ffffffff81000298>] do_one_initcall+0xc8/0x1f0
[<ffffffff811a731d>] ? __vunmap+0x9d/0x100
[<ffffffff810eb9a0>] do_init_module+0x30/0x1b0
[<ffffffff810edfa6>] load_module+0x686/0x710
[<ffffffff810ebb20>] ? do_init_module+0x1b0/0x1b0
[<ffffffff810ee1db>] SyS_init_module+0x9b/0xc0
[<ffffffff8158f7a9>] system_call_fastpath+0x16/0x1b

Fixes: 8fec051eea73 (cpufreq: Convert existing drivers to use cpufreq_freq_transition_{begin|end})
Reported-and-tested-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: 3.15+ <stable@vger.kernel.org> # 3.15+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: Convert existing drivers to use cpufreq_freq_transition_{begin|end}

CPUFreq core has new infrastructure that would guarantee serialized calls to
target() or target_index() callbacks. These are called
cpufreq_freq_transition_begin() and cpufreq_freq_transition_end().

This patch converts existing drivers to use these new set of routines.

Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: send new set of notification for transition failures

In the current code, if we fail during a frequency transition, we
simply send the POSTCHANGE notification with the old frequency. This
isn't enough.

One of the core users of these notifications is the code responsible
for keeping loops_per_jiffy aligned with frequency changes. And mostly
it is written as:

if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) ||
(val == CPUFREQ_POSTCHANGE && freq->old > freq->new)) {
update-loops-per-jiffy...
}

So, suppose we are changing to a higher frequency and failed during
transition, then following will happen:
- CPUFREQ_PRECHANGE notification with freq-new > freq-old
- CPUFREQ_POSTCHANGE notification with freq-new == freq-old

The first one will update loops_per_jiffy and second one will do
nothing. Even if we send the 2nd notification by exchanging values of
freq-new and old, some users of these notifications might get
unstable.

This can be fixed by simply calling cpufreq_notify_post_transition()
with error code and this routine will take care of sending
notifications in the correct order.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[rjw: Folded 3 patches into one, rebased unicore2 changes]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Merge branch 'pm-cpufreq'

* pm-cpufreq: (167 commits)
cpufreq: create per policy rwsem instead of per CPU cpu_policy_rwsem
intel_pstate: Add Baytrail support
intel_pstate: Refactor driver to support CPUs with different MSR layouts
cpufreq: Implement light weight ->target_index() routine
PM / OPP: rename header to linux/pm_opp.h
PM / OPP: rename data structures to dev_pm equivalents
PM / OPP: rename functions to dev_pm_opp*
cpufreq / governor: Remove fossil comment
cpufreq: exynos4210: Use the common clock framework to set APLL clock rate
cpufreq: exynos4x12: Use the common clock framework to set APLL clock rate
cpufreq: Detect spurious invocations of update_policy_cpu()
cpufreq: pmac64: enable cpufreq on iMac G5 (iSight) model
cpufreq: pmac64: provide cpufreq transition latency for older G5 models
cpufreq: pmac64: speed up frequency switch
cpufreq: highbank-cpufreq: Enable Midway/ECX-2000
exynos-cpufreq: fix false return check from "regulator_set_voltage"
speedstep-centrino: Remove unnecessary braces
acpi-cpufreq: Add comment under ACPI_ADR_SPACE_SYSTEM_IO case
cpufreq: arm-big-little: use clk_get instead of clk_get_sys
cpufreq: exynos: Show a list of available frequencies
...

Conflicts:
drivers/devfreq/exynos/exynos5_bus.c

cpufreq: pcc: don't initialize part of policy set by core

Many common initializations of struct policy are moved to core now and hence
this driver doesn't need to do it. This patch removes such code.

Most recent of those changes is to call ->get() in the core after calling
->init().

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: add new routine cpufreq_verify_within_cpu_limits()

Most of the users of cpufreq_verify_within_limits() calls it for
limiting with min/max from policy->cpuinfo. We can make that code
simple by introducing another routine which will do this for them
automatically.

This patch adds another routine cpufreq_verify_within_cpu_limits()
and updates others to use it.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

pcc_freq: convert acpi_get_handle() to acpi_has_method()

acpi_has_method() is a new ACPI API introduced to check
the existence of an ACPI control method.

It can be used to replace acpi_get_handle() in the case that
1. the calling function doesn't need the ACPI handle of the control method.
and
2. the calling function doesn't care the reason why the method is unavailable.

Convert acpi_get_handle() to acpi_has_method()
in drivers/cpufreq/pcc_freq.c in this patch.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: Drop the owner field from struct cpufreq_driver

We don't need to set .owner = THIS_MODULE any more in cpufreq drivers
as this field isn't used any more by the cpufreq core.

This patch removes it and updates all dependent drivers accordingly.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: pcc: call CPUFREQ_POSTCHANGE notfier in error cases

PRECHANGE and POSTCHANGE notifiers must be called in groups, i.e
either both should be called or both shouldn't be.

In case we have started PRECHANGE notifier and found an error, we
must call POSTCHANGE notifier with freqs.new = freqs.old to guarantee
that the sequence of calling notifiers is complete.

This patch fixes it.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: Notify all policy->cpus in cpufreq_notify_transition()

policy->cpus contains all online cpus that have single shared clock line. And
their frequencies are always updated together.

Many SMP system's cpufreq drivers take care of this in individual drivers but
the best place for this code is in cpufreq core.

This patch modifies cpufreq_notify_transition() to notify frequency change for
all cpus in policy->cpus and hence updates all users of this API.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/pcc-cpufreq.c: fix error return code

Convert a 0 error return code to a negative one, as returned elsewhere in the
function.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
identifier ret;
expression e,e1,e2,e3,e4,x;
@@

(
if (\(ret != 0\|ret < 0\) || ...) { ... return ...; }
|
ret = 0
)
... when != ret = e1
*x = \(kmalloc\|kzalloc\|kcalloc\|devm_kzalloc\|ioremap\|ioremap_nocache\|devm_ioremap\|devm_ioremap_nocache\)(...);
... when != x = e2
when != ret = e3
*if (x == NULL || ...)
{
... when != ret = e4
* return ret;
}
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

drivers/cpufreq/pcc-cpufreq.c: avoid NULL pointer dereference

per_cpu(processors, n) can be NULL, resulting in:

Loading CPUFreq modules[ 437.661360] BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<ffffffffa0434314>] pcc_cpufreq_cpu_init+0x74/0x220 [pcc_cpufreq]

It's better to avoid the oops by failing the driver, and allowing the
system to boot.

Signed-off-by: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Len Brown <lenb@kernel.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[CPUFREQ] Move x86 drivers to drivers/cpufreq/

Signed-off-by: Dave Jones <davej@redhat.com>

ACPI: cpufreq: Use platform devices to load ACPI PPC and PCC drivers

The acpi-cpufreq and pcc-cpufreq drivers are loaded through per-CPU
module aliases. This can result in many unnecessary load requests during
boot if another frequency module, such as intel_pstate, is already
active. For instance, on a typical Intel system, one can observe that
udev makes 2x#CPUs attempts to insert acpi_cpufreq and 1x#CPUs attempts
for pcc_cpufreq. All these tries then fail if another frequency module
is already registered.

In the worst case, without the recent fix in commit 0254127ab977e
("module: Don't wait for GOING modules"), these module loads occupied
all udev workers and had their initialization attempts ran sequentially.
Resolving all these loads then on some larger machines took too long,
prevented other hardware from getting its drivers initialized and
resulted in a failed boot. Discussion over these duplicate module
requests ended up with a conclusion that only one load attempt should be
ideally made.

Both acpi-cpufreq and pcc-cpufreq drivers use platform firmware controls
which are defined by ACPI. It is possible to treat these interfaces as
platform devices.

The patch extends the ACPI parsing logic to check the ACPI namespace if
the PPC or PCC interface is present and creates a virtual platform
device for each if it is available. The acpi-cpufreq and pcc-cpufreq
drivers are then updated to map to these devices.

This allows to try loading acpi-cpufreq and pcc-cpufreq only once during
boot and only if a given interface is available in the firmware.

Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
[ rjw: whitespace and error message log level adjustments, subject edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: pcc-cpufreq: Mark sometimes used ID structs as __maybe_unused

Not used when MODULE is not defined.

Fixes the following W=1 kernel build warning(s):

drivers/cpufreq/pcc-cpufreq.c:619:36: warning: ‘processor_device_ids’ defined but not used [-Wunused-const-variable=]
619 | static const struct acpi_device_id processor_device_ids[] = {
| ^~~~~~~~~~~~~~~~~~~~

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: Avoid creating excessively large stack frames

In the process of modifying a cpufreq policy, the cpufreq core makes
a copy of it including all of the internals which is stored on the
CPU stack. Because struct cpufreq_policy is relatively large, this
may cause the size of the stack frame to exceed the 2 KB limit and
so the GCC complains when -Wframe-larger-than= is used.

In fact, it is not necessary to copy the entire policy structure
in order to modify it, however.

First, because cpufreq_set_policy() obtains the min and max policy
limits from frequency QoS now, it is not necessary to pass the limits
to it from the callers. The only things that need to be passed to it
from there are the new governor pointer or (if there is a built-in
governor in the driver) the "policy" value representing the governor
choice. They both can be passed as individual arguments, though, so
make cpufreq_set_policy() take them this way and rework its callers
accordingly. This avoids making copies of cpufreq policies in the
callers of cpufreq_set_policy().

Second, cpufreq_set_policy() still needs to pass the new policy
data to the ->verify() callback of the cpufreq driver whose task
is to sanitize the min and max policy limits. It still does not
need to make a full copy of struct cpufreq_policy for this purpose,
but it needs to pass a few items from it to the driver in case they
are needed (different drivers have different needs in that respect
and all of them have to be covered). For this reason, introduce
struct cpufreq_policy_data to hold copies of the members of
struct cpufreq_policy used by the existing ->verify() driver
callbacks and pass a pointer to a temporary structure of that
type to ->verify() (instead of passing a pointer to full struct
cpufreq_policy to it).

While at it, notice that intel_pstate and longrun don't really need
to verify the "policy" value in struct cpufreq_policy, so drop those
check from them to avoid copying "policy" into struct
cpufreq_policy_data (which allows it to be slightly smaller).

Also while at it fix up white space in a couple of places and make
cpufreq_set_policy() static (as it can be so).

Fixes: 3000ce3c52f8 ("cpufreq: Use per-policy frequency QoS")
Link: https://lore.kernel.org/linux-pm/CAMuHMdX6-jb1W8uC2_237m8ctCpsnGp=JCxqt8pCWVqNXHmkVg@mail.gmail.com
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

remove ioremap_nocache and devm_ioremap_nocache

ioremap has provided non-cached semantics by default since the Linux 2.6
days, so remove the additional ioremap_nocache interface.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>

cpufreq: pcc-cpufreq: Fail initialization if driver cannot be registered

Make pcc_cpufreq_init() return error codes when the driver cannot be
registered. Otherwise the driver can shows up loaded via lsmod even
though it failed initialization. This is confusing to the user.

Signed-off-by: David Arcari <darcari@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: pcc-cpufreq: remove unneeded semicolon

The semicolon is unneeded, so remove it.

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: intel_pstate: Register when ACPI PCCH is present

Currently, intel_pstate doesn't register if _PSS is not present on
HP Proliant systems, because it expects the firmware to take over
CPU performance scaling in that case. However, if ACPI PCCH is
present, the firmware expects the kernel to use it for CPU
performance scaling and the pcc-cpufreq driver is loaded for that.

Unfortunately, the firmware interface used by that driver is not
scalable for fundamental reasons, so pcc-cpufreq is way suboptimal
on systems with more than just a few CPUs. In fact, it is better to
avoid using it at all.

For this reason, modify intel_pstate to look for ACPI PCCH if _PSS
is not present and register if it is there. Also prevent the
pcc-cpufreq driver from trying to initialize itself if intel_pstate
has been registered already.

Fixes: fbbcdc0744da (intel_pstate: skip the driver if ACPI has power mgmt option)
Reported-by: Andreas Herrmann <aherrmann@suse.com>
Reviewed-by: Andreas Herrmann <aherrmann@suse.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Tested-by: Andreas Herrmann <aherrmann@suse.com>
Cc: 4.16+ <stable@vger.kernel.org> # 4.16+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: pcc-cpufreq: Disable dynamic scaling on many-CPU systems

The firmware interface used by the pcc-cpufreq driver is
fundamentally not scalable and using it for dynamic CPU performance
scaling on systems with many CPUs leads to degraded performance.

For this reason, disable dynamic CPU performance scaling on systems
with pcc-cpufreq where the number of CPUs present at the driver init
time is greater than 4. Also make the driver print corresponding
complaints to the kernel log.

Reported-by: Andreas Herrmann <aherrmann@suse.com>
Tested-by: Andreas Herrmann <aherrmann@suse.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Revert "cpufreq: pcc-cpufreq: update default value of cpuinfo_transition_latency"

This reverts commit 790d849bf811a8ab5d4cd2cce0f6fda92f6aebf2.

Using a v4.7-rc7 kernel on a HP ProLiant triggered following messages

pcc-cpufreq: (v1.10.00) driver loaded with frequency limits: 1200 MHz, 2800 MHz
cpufreq: ondemand governor failed, too long transition latency of HW, fallback to performance governor

The last line was shown for each CPU in the system.
Testing v4.5 (where commit 790d849b was integrated) triggered
similar messages. Same behaviour on a 2nd HP Proliant system.

So commit 790d849bf (cpufreq: pcc-cpufreq: update default value of
cpuinfo_transition_latency) causes the system to use performance
governor which, I guess, was not the intention of the patch.

Enabling debug output in pcc-cpufreq provides following verbose output:

pcc-cpufreq: (v1.10.00) driver loaded with frequency limits: 1200 MHz, 2800 MHz
pcc_get_offset: for CPU 0: pcc_cpu_data input_offset: 0x44, pcc_cpu_data output_offset: 0x48
init: policy->max is 2800000, policy->min is 1200000
get: get_freq for CPU 0
get: SUCCESS: (virtual) output_offset for cpu 0 is 0xffffc9000d7c0048, contains a value of: 0xff06. Speed is: 168000 MHz
cpufreq: ondemand governor failed, too long transition latency of HW, fallback to performance governor
target: CPU 0 should go to target freq: 2800000 (virtual) input_offset is 0xffffc9000d7c0044
target: was SUCCESSFUL for cpu 0

I am asking to revert 790d849bf to re-enable usage of ondemand
governor with pcc-cpufreq.

Fixes: 790d849bf (cpufreq: pcc-cpufreq: update default value of cpuinfo_transition_latency)
CC: <stable@vger.kernel.org> # 4.5+
Signed-off-by: Andreas Herrmann <aherrmann@suse.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: pcc-cpufreq: Fix doorbell.access_width

Commit 920de6ebfab8 (ACPICA: Hardware: Enhance
acpi_hw_validate_register() with access_width/bit_offset awareness)
apparently exposed a latent bug, doorbell.access_width is initialized
to 64, but per Lv Zheng, it should be 4, and indeed, making that
change does bring pcc-cpufreq back to life.

Fixes: 920de6ebfab8 (ACPICA: Hardware: Enhance acpi_hw_validate_register() with access_width/bit_offset awareness)
Suggested-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: pcc-cpufreq: update default value of cpuinfo_transition_latency

The cpufreq documentation specifies

policy->cpuinfo.transition_latency the time it takes on this CPU to
switch between two frequencies in
nanoseconds (if appropriate, else
specify CPUFREQ_ETERNAL)

currently pcc-cpufreq does not expose the value and sets it to zero. I
changed the pcc-cpufreq driver and it's documentation to conform to the
default value specified in Documentation/cpu-freq/cpu-drivers.txt

Signed-off-by: Jacob Tanenbaum <jtanenba@redhat.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: pcc: Enable autoload of pcc-cpufreq for ACPI processors

The pcc-cpufreq driver is not automatically loaded on systems where
the platform's power management setting requires this driver.
Instead, on those systems no CPU frequency driver is registered and
active.

Make the autoloading matching criteria for loading the pcc-cpufreq
driver the same as done in acpi-cpufreq by commit c655affbd524d01
("ACPI / cpufreq: Add ACPI processor device IDs to acpi-cpufreq").

x86 CPU frequency drivers are now typically autoloaded by specifying
MODULE_DEVICE_TABLE entries and x86cpu model specific matching.
But pcc-cpufreq was omitted when acpi-cpufreq and other drivers were
changed to use this approach.

Both acpi-cpufreq and pcc-cpufreq depend on a distinct and mutually
exclusive set of ACPI methods which are not directly tied to specific
processor model numbers. Both of these drivers have init routines
which look for their required ACPI methods. As a result, only the
appropriate driver registers as the cpu frequency driver and the other
one ends up being unloaded.

Tested on various systems where acpi-cpufreq, intel_pstate, and
pcc-cpufreq are the expected cpu frequency drivers.

Signed-off-by: Lenny Szubowicz <lszubowi@redhat.com>
Signed-off-by: Joseph Szczypek <joseph.szczypek@hp.com>
Reported-by: Trinh Dao <trinh.dao@hp.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: pcc-cpufreq: Fix wait_event() under spinlock

Fix the following bug introduced by commit 8fec051eea73 (cpufreq:
Convert existing drivers to use cpufreq_freq_transition_{begin|end})
that forgot to move the spin_lock() in pcc_cpufreq_target() past
cpufreq_freq_transition_begin() which calls wait_event():

BUG: sleeping function called from invalid context at drivers/cpufreq/cpufreq.c:370
in_atomic(): 1, irqs_disabled(): 0, pid: 2636, name: modprobe
Preemption disabled at:[<ffffffffa04d74d7>] pcc_cpufreq_target+0x27/0x200 [pcc_cpufreq]
[ 51.025044]
CPU: 57 PID: 2636 Comm: modprobe Tainted: G E 3.17.0-default #7
Hardware name: Hewlett-Packard ProLiant DL980 G7, BIOS P66 07/07/2010
00000000ffffffff ffff88026c46b828 ffffffff81589dbd 0000000000000000
ffff880037978090 ffff88026c46b848 ffffffff8108e1df ffff880037978090
0000000000000000 ffff88026c46b878 ffffffff8108e298 ffff88026d73ec00
Call Trace:
[<ffffffff81589dbd>] dump_stack+0x4d/0x90
[<ffffffff8108e1df>] ___might_sleep+0x10f/0x180
[<ffffffff8108e298>] __might_sleep+0x48/0xd0
[<ffffffff8145b905>] cpufreq_freq_transition_begin+0x75/0x140 drivers/cpufreq/cpufreq.c:370 wait_event(policy->transition_wait, !policy->transition_ongoing);
[<ffffffff8108fc99>] ? preempt_count_add+0xb9/0xc0
[<ffffffffa04d7513>] pcc_cpufreq_target+0x63/0x200 [pcc_cpufreq] drivers/cpufreq/pcc-cpufreq.c:207 spin_lock(&pcc_lock);
[<ffffffff810e0d0f>] ? update_ts_time_stats+0x7f/0xb0
[<ffffffff8145be55>] __cpufreq_driver_target+0x85/0x170
[<ffffffff8145e4c8>] od_check_cpu+0xa8/0xb0
[<ffffffff8145ef10>] dbs_check_cpu+0x180/0x1d0
[<ffffffff8145f310>] cpufreq_governor_dbs+0x3b0/0x720
[<ffffffff8145ebe3>] od_cpufreq_governor_dbs+0x33/0xe0
[<ffffffff814593d9>] __cpufreq_governor+0xa9/0x210
[<ffffffff81459fb2>] cpufreq_set_policy+0x1e2/0x2e0
[<ffffffff8145a6cc>] cpufreq_init_policy+0x8c/0x110
[<ffffffff8145c9a0>] ? cpufreq_update_policy+0x1b0/0x1b0
[<ffffffff8108fb99>] ? preempt_count_sub+0xb9/0x100
[<ffffffff8145c6c6>] __cpufreq_add_dev+0x596/0x6b0
[<ffffffffa016c608>] ? pcc_cpufreq_probe+0x4b4/0x4b4 [pcc_cpufreq]
[<ffffffff8145c7ee>] cpufreq_add_dev+0xe/0x10
[<ffffffff81408e81>] subsys_interface_register+0xc1/0xf0
[<ffffffff8108fb99>] ? preempt_count_sub+0xb9/0x100
[<ffffffff8145b3d7>] cpufreq_register_driver+0x117/0x2a0
[<ffffffffa016c65d>] pcc_cpufreq_init+0x55/0x9f8 [pcc_cpufreq]
[<ffffffffa016c608>] ? pcc_cpufreq_probe+0x4b4/0x4b4 [pcc_cpufreq]
[<ffffffff81000298>] do_one_initcall+0xc8/0x1f0
[<ffffffff811a731d>] ? __vunmap+0x9d/0x100
[<ffffffff810eb9a0>] do_init_module+0x30/0x1b0
[<ffffffff810edfa6>] load_module+0x686/0x710
[<ffffffff810ebb20>] ? do_init_module+0x1b0/0x1b0
[<ffffffff810ee1db>] SyS_init_module+0x9b/0xc0
[<ffffffff8158f7a9>] system_call_fastpath+0x16/0x1b

Fixes: 8fec051eea73 (cpufreq: Convert existing drivers to use cpufreq_freq_transition_{begin|end})
Reported-and-tested-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: 3.15+ <stable@vger.kernel.org> # 3.15+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: Convert existing drivers to use cpufreq_freq_transition_{begin|end}

CPUFreq core has new infrastructure that would guarantee serialized calls to
target() or target_index() callbacks. These are called
cpufreq_freq_transition_begin() and cpufreq_freq_transition_end().

This patch converts existing drivers to use these new set of routines.

Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: send new set of notification for transition failures

In the current code, if we fail during a frequency transition, we
simply send the POSTCHANGE notification with the old frequency. This
isn't enough.

One of the core users of these notifications is the code responsible
for keeping loops_per_jiffy aligned with frequency changes. And mostly
it is written as:

if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) ||
(val == CPUFREQ_POSTCHANGE && freq->old > freq->new)) {
update-loops-per-jiffy...
}

So, suppose we are changing to a higher frequency and failed during
transition, then following will happen:
- CPUFREQ_PRECHANGE notification with freq-new > freq-old
- CPUFREQ_POSTCHANGE notification with freq-new == freq-old

The first one will update loops_per_jiffy and second one will do
nothing. Even if we send the 2nd notification by exchanging values of
freq-new and old, some users of these notifications might get
unstable.

This can be fixed by simply calling cpufreq_notify_post_transition()
with error code and this routine will take care of sending
notifications in the correct order.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[rjw: Folded 3 patches into one, rebased unicore2 changes]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: pcc: don't initialize part of policy set by core

Many common initializations of struct policy are moved to core now and hence
this driver doesn't need to do it. This patch removes such code.

Most recent of those changes is to call ->get() in the core after calling
->init().

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: add new routine cpufreq_verify_within_cpu_limits()

Most of the users of cpufreq_verify_within_limits() calls it for
limiting with min/max from policy->cpuinfo. We can make that code
simple by introducing another routine which will do this for them
automatically.

This patch adds another routine cpufreq_verify_within_cpu_limits()
and updates others to use it.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

pcc_freq: convert acpi_get_handle() to acpi_has_method()

acpi_has_method() is a new ACPI API introduced to check
the existence of an ACPI control method.

It can be used to replace acpi_get_handle() in the case that
1. the calling function doesn't need the ACPI handle of the control method.
and
2. the calling function doesn't care the reason why the method is unavailable.

Convert acpi_get_handle() to acpi_has_method()
in drivers/cpufreq/pcc_freq.c in this patch.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: Drop the owner field from struct cpufreq_driver

We don't need to set .owner = THIS_MODULE any more in cpufreq drivers
as this field isn't used any more by the cpufreq core.

This patch removes it and updates all dependent drivers accordingly.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: pcc: call CPUFREQ_POSTCHANGE notfier in error cases

PRECHANGE and POSTCHANGE notifiers must be called in groups, i.e
either both should be called or both shouldn't be.

In case we have started PRECHANGE notifier and found an error, we
must call POSTCHANGE notifier with freqs.new = freqs.old to guarantee
that the sequence of calling notifiers is complete.

This patch fixes it.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: Notify all policy->cpus in cpufreq_notify_transition()

policy->cpus contains all online cpus that have single shared clock line. And
their frequencies are always updated together.

Many SMP system's cpufreq drivers take care of this in individual drivers but
the best place for this code is in cpufreq core.

This patch modifies cpufreq_notify_transition() to notify frequency change for
all cpus in policy->cpus and hence updates all users of this API.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/pcc-cpufreq.c: fix error return code

Convert a 0 error return code to a negative one, as returned elsewhere in the
function.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
identifier ret;
expression e,e1,e2,e3,e4,x;
@@

(
if (\(ret != 0\|ret < 0\) || ...) { ... return ...; }
|
ret = 0
)
... when != ret = e1
*x = \(kmalloc\|kzalloc\|kcalloc\|devm_kzalloc\|ioremap\|ioremap_nocache\|devm_ioremap\|devm_ioremap_nocache\)(...);
... when != x = e2
when != ret = e3
*if (x == NULL || ...)
{
... when != ret = e4
* return ret;
}
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

drivers/cpufreq/pcc-cpufreq.c: avoid NULL pointer dereference

per_cpu(processors, n) can be NULL, resulting in:

Loading CPUFreq modules[ 437.661360] BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<ffffffffa0434314>] pcc_cpufreq_cpu_init+0x74/0x220 [pcc_cpufreq]

It's better to avoid the oops by failing the driver, and allowing the
system to boot.

Signed-off-by: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Len Brown <lenb@kernel.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[CPUFREQ] Move x86 drivers to drivers/cpufreq/

Signed-off-by: Dave Jones <davej@redhat.com>