Commit 5800043b (cpufreq: convert cpufreq_driver to using RCU) causes
the following call trace to be spit on boot:

 BUG: sleeping function called from invalid context at /scratch/rafael/work/linux-pm/mm/slab.c:3179
 in_atomic(): 0, irqs_disabled(): 0, pid: 292, name: systemd-udevd
 2 locks held by systemd-udevd/292:
  #0:  (subsys mutex){+.+.+.}, at: [<ffffffff8146851a>] subsys_interface_register+0x4a/0xe0
  #1:  (rcu_read_lock){.+.+.+}, at: [<ffffffff81538210>] cpufreq_add_dev_interface+0x60/0x5e0
 Pid: 292, comm: systemd-udevd Not tainted 3.9.0-rc8+ #323
 Call Trace:
  [<ffffffff81072c90>] __might_sleep+0x140/0x1f0
  [<ffffffff811581c2>] kmem_cache_alloc+0x42/0x2b0
  [<ffffffff811e7179>] sysfs_new_dirent+0x59/0x130
  [<ffffffff811e63cb>] sysfs_add_file_mode+0x6b/0x110
  [<ffffffff81538210>] ? cpufreq_add_dev_interface+0x60/0x5e0
  [<ffffffff810a3254>] ? __lock_is_held+0x54/0x80
  [<ffffffff811e647d>] sysfs_add_file+0xd/0x10
  [<ffffffff811e6541>] sysfs_create_file+0x21/0x30
  [<ffffffff81538280>] cpufreq_add_dev_interface+0xd0/0x5e0
  [<ffffffff81538210>] ? cpufreq_add_dev_interface+0x60/0x5e0
  [<ffffffffa000337f>] ? acpi_processor_get_platform_limit+0x32/0xbb [processor]
  [<ffffffffa022f540>] ? do_drv_write+0x70/0x70 [acpi_cpufreq]
  [<ffffffff810a3254>] ? __lock_is_held+0x54/0x80
  [<ffffffff8106c97e>] ? up_read+0x1e/0x40
  [<ffffffff8106e632>] ? __blocking_notifier_call_chain+0x72/0xc0
  [<ffffffff81538dbd>] cpufreq_add_dev+0x62d/0xae0
  [<ffffffff815389b8>] ? cpufreq_add_dev+0x228/0xae0
  [<ffffffff81468569>] subsys_interface_register+0x99/0xe0
  [<ffffffffa014d000>] ? 0xffffffffa014cfff
  [<ffffffff81535d5d>] cpufreq_register_driver+0x9d/0x200
  [<ffffffffa014d000>] ? 0xffffffffa014cfff
  [<ffffffffa014d0e9>] acpi_cpufreq_init+0xe9/0x1000 [acpi_cpufreq]
  [<ffffffff810002fa>] do_one_initcall+0x11a/0x170
  [<ffffffff810b4b87>] load_module+0x1cf7/0x2920
  [<ffffffff81322580>] ? ddebug_proc_open+0xb0/0xb0
  [<ffffffff816baee0>] ? retint_restore_args+0xe/0xe
  [<ffffffff810b5887>] sys_init_module+0xd7/0x120
  [<ffffffff816bb6d2>] system_call_fastpath+0x16/0x1b

which is quite obvious, because that commit put (multiple instances
of) sysfs_create_file() under rcu_read_lock()/rcu_read_unlock(),
although sysfs_create_file() may cause memory to be allocated with
GFP_KERNEL and that may sleep, which is not permitted in RCU read
critical section.

Revert the buggy commit altogether along with some changes on top
of it.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Add Viresh as a co-maintainer of cpufreq framework.

This would mostly be for cpufreq core and ARM drivers but not
restricted to them.

Also add a pointer to the git tree cpufreq patches are pulled into.

[rjw: Changelog]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tentatively-acked-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

gcc-3.8 correctly found that the variables set by find_freq_tables()
are not initialized if this function is called on something other
than a pxa2xx or pxa3xx:

pxa2xx-cpufreq.c: In function 'pxa_verify_policy':
pxa2xx-cpufreq.c:272:6: warning: 'pxa_freqs_table' may be used uninitialized in this function [-Wmaybe-uninitialized]
pxa2xx-cpufreq.c: In function 'pxa_set_target':
pxa2xx-cpufreq.c:345:23: warning: 'pxa_freq_settings' may be used uninitialized in this function [-Wmaybe-uninitialized]

Rather than adding a bogus initialization that would let us
get a little further before crashing, add an explicit BUG().
We know that this code is designed to run on only these cpus,
so this will fix the build warning and give a more helpful
diagnostic if the code ever changes to run on other machines.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

For arm S5pv210 with allmodconfig, ARM_S5PV210_CPUFREQ need
CONFIG_CPU_FREQ_TABLE=y, or will cause compiling issue.

The related operation:
+ arm-linux-gnu-ld -EL -p --no-undefined -X --build-id -X -o .tmp_vmlinux1 -T /root/linux-next/arch/arm/kernel/vmlinux.lds arch/arm/kernel/head.o init/built-in.o --start-group usr/built-in.o arch/arm/nwfpe/built-in.o arch/arm/vfp/built-in.o arch/arm/kernel/built-in.o arch/arm/mm/built-in.o arch/arm/common/built-in.o arch/arm/net/built-in.o arch/arm/crypto/built-in.o arch/arm/mach-s5pv210/built-in.o arch/arm/plat-samsung/built-in.o kernel/built-in.o mm/built-in.o fs/built-in.o ipc/built-in.o security/built-in.o crypto/built-in.o block/built-in.o arch/arm/lib/lib.a lib/lib.a arch/arm/lib/built-in.o lib/built-in.o drivers/built-in.o sound/built-in.o firmware/built-in.o net/built-in.o --end-group

The related errors:
drivers/built-in.o: In function `s5pv210_target':
drivers/cpufreq/s5pv210-cpufreq.c:225: undefined reference to `cpufreq_frequency_table_target'
drivers/cpufreq/s5pv210-cpufreq.c:237: undefined reference to `cpufreq_frequency_table_target'
drivers/built-in.o: In function `s5pv210_verify_speed':
drivers/cpufreq/s5pv210-cpufreq.c:182: undefined reference to `cpufreq_frequency_table_verify'
drivers/built-in.o: In function `s5pv210_cpu_init':
drivers/cpufreq/s5pv210-cpufreq.c:556: undefined reference to `cpufreq_frequency_table_get_attr'
drivers/cpufreq/s5pv210-cpufreq.c:560: undefined reference to `cpufreq_frequency_table_cpuinfo'
make: *** [vmlinux] Error 1
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Parent node must be put after using it to balance its usage count. This was
missing in cpufreq-cpu0 driver. Fix it.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

This driver isn't updated to work with latest cpufreq core updates that happened
recently. Fix them.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

DT nodes should be put using of_node_put() to balance their usage counts. This
is not done properly in ARM's big LITTLE driver. Fix it.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Some cpufreq drivers implement their own governor and so don't need
us to call generic governors interface via __cpufreq_governor(). Few
recent commits haven't obeyed this law well and we saw some
regressions.

This patch is an attempt to fix the above issue.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reported-and-tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Tested-by: Dirk Brandewie <dirk.brandewie@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

As per the OPP library documentation(Documentation/power/opp.txt) all
OPP find/get calls should be protected by RCU locks.
Signed-off-by: Amit Daniel Kachhap <amit.daniel@samsung.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

When reading the cpu speed, round it to the closest available
frequency from the table.
Signed-off-by: Mats Fagerstrom <mats.fagerstrom@stericsson.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

__cpufreq_governor() must be called with a correct policy->cpus mask.
In __cpufreq_remove_dev() we initially clear policy->cpus with
cpumask_clear_cpu() and then call
__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT). If the governor
is doing some per-cpu stuff in EXIT callback, this can create
uncertain behavior.

Generic governors in drivers/cpufreq/ doesn't do any per-cpu stuff
in EXIT callback and so we don't face any issues currently. But its
better to keep the code clean, so we don't face any issues in future.

Now, we call cpumask_clear_cpu() only when multiple cpus are managed
by policy.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

This function is called quite often from other subsystems.
Removed unused call to intel_pstate_get_min_max().
Also when "policy->policy == CPUFREQ_POLICY_PERFORMANCE", then
no need to do calculations as the limits will be forced anyway.
Also corrected filename in the header.
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

As multi-platform build is being adopted by more and more ARM platforms,
initcall function should be used very carefully.  For example, when
CONFIG_ARM_OMAP2PLUS_CPUFREQ is built in the kernel, omap_cpufreq_init()
will be called on all the platforms to initialize omap-cpufreq driver.

Further, on OMAP, we now use Soc generic cpufreq-cpu0 driver using device
tree entries.  To allow cpufreq-cpu0 and omap-cpufreq drivers to co-exist
for OMAP in a single image, we need to ensure the following:
 1. With device tree boot, we use cpufreq-cpu0
 2. With non device tree boot, we use omap-cpufreq

In the case of (1), we will have cpu OPPs and regulator registered
as part of the device tree nodes, to ensure that omap-cpufreq
and cpufreq-cpu0 don't conflict in managing the frequency of the
same CPU, we should not permit omap-cpufreq to be probed.

In the case of (2), we will not have the cpufreq-cpu0 device, hence
only omap-cpufreq will be active.

To eliminate this undesired these effects, we change omap-cpufreq
driver to have it instantiated as a platform_driver and register
"omap-cpufreq" device only when booted without device tree nodes on
OMAP platforms.

This allows the following:
 a) Will only run on platforms that create the platform_device
    "omap-cpufreq".
 b) Since the platform_device is registered only when device tree nodes
    are *not* populated, omap-cpufreq driver does not conflict with
    the usage of cpufreq-cpu0 driver which is used on OMAP platforms when
    device tree nodes are present.

Inspired by commit 5553f9e2
(cpufreq: instantiate cpufreq-cpu0 as a platform_driver)

[robherring2@gmail.com: reported conflict of omap-cpufreq vs other
driver in an non-device tree supported boot]
Reported-by: Rob Herring <robherring2@gmail.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

The OPP library support is needed for exynos5440 cpu frequency
dynamic scaling driver.
Signed-off-by: Amit Daniel Kachhap <amit.daniel@samsung.com>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch helps to have single binary for exynos5440 and previous
exynos soc's. This change is needed for adding exynos5440 cpufreq driver
which does not uses exynos-cpufreq common file and adds it own driver.
Signed-off-by: Amit Daniel Kachhap <amit.daniel@samsung.com>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch adds dvfs support for exynos5440 SOC. This soc has 4 cores and
they scale at same frequency. The nature of exynos5440 clock controller is
different from previous exynos controllers so not using the common exynos
cpufreq framework. The major difference being interrupt notification for
frequency change. Also, OPP library is used for device tree parsing to get
different parameters like frequency, voltage etc. Since the opp library sorts
the frequency table in ascending order so they are again re-arranged in
descending order. This will have one-to-one mapping with the clock controller
state management logic.
Signed-off-by: Amit Daniel Kachhap <amit.daniel@samsung.com>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Future AMD processors, starting with Family 16h, can provide software
with feedback on how the workload may respond to frequency change --
memory-bound workloads will not benefit from higher frequency, where
as compute-bound workloads will. This patch enables this "frequency
sensitivity feedback" to aid the ondemand governor to make better
frequency change decisions by hooking into the powersave bias.
Signed-off-by: Jacob Shin <jacob.shin@amd.com>
Acked-by: Thomas Renninger <trenn@suse.de>
Acked-by: Borislav Petkov <bp@suse.de>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

This allows for another [arch specific] driver to hook into existing
powersave bias function of the ondemand governor. i.e. This allows AMD
specific powersave bias function (in a separate AMD specific driver)
to aid ondemand governor's frequency transition decisions.
Signed-off-by: Jacob Shin <jacob.shin@amd.com>
Acked-by: Thomas Renninger <trenn@suse.de>
Acked-by: Borislav Petkov <bp@suse.de>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

We eventually would like to remove the rwlock cpufreq_driver_lock or
convert it back to a spinlock and protect the read sections with RCU.
The first step in that direction is to make cpufreq_driver use RCU.
I don't see an easy wasy to protect the cpufreq_cpu_data structure
with RCU, so I am leaving it with the rwlock for now since under
certain configs __cpufreq_cpu_get is a hot spot with 256+ cores.

[rjw: Subject, changelog, white space]
Signed-off-by: Nathan Zimmer <nzimmer@sgi.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch moves cpufreq driver of powerpc platforms/cell to drivers/cpufreq.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch moves cpufreq driver of SPARC architecture to drivers/cpufreq.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch moves cpufreq driver of UNICORE-2 architecture to drivers/cpufreq.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch moves cpufreq driver of SUPERH architecture to drivers/cpufreq.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch moves cpufreq driver of MIPS architecture to drivers/cpufreq.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: John Crispin <blogic@openwrt.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch moves cpufreq driver of IA64 architecture to drivers/cpufreq.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch moves cpufreq drivers of CRIS architecture to drivers/cpufreq.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch moves cpufreq driver of BLACKFIN architecture to drivers/cpufreq.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Steven Miao <realmz6@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch moves cpufreq driver of AVR32 based at32ap platform to
drivers/cpufreq.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch moves cpufreq driver of ARM based sa11x0 platform to drivers/cpufreq.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch moves cpufreq driver of ARM based integrator platform to
drivers/cpufreq.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch moves cpufreq driver of ARM based pxa2xx platform to drivers/cpufreq.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Eric Miao <eric.y.miao@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch moves cpufreq driver of ARM based pxa3xx platform to drivers/cpufreq.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Eric Miao <eric.y.miao@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch moves cpufreq driver of ARM based davinci platform to
drivers/cpufreq.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Sekhar Nori <nsekhar@ti.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch moves cpufreq driver of ARM based tegra platform to drivers/cpufreq.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Normally we keep drivers in alphabetical inside Kconfig and Makefile and over
time this was broken for ARM cpufreq drivers. Fix it.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

big LITTLE is ARM's new Architecture focussing power/performance needs of modern
world. More information about big LITTLE can be found here:

http://www.arm.com/products/processors/technologies/biglittleprocessing.php
http://lwn.net/Articles/481055/

In order to keep cpufreq support for all big LITTLE platforms simple/generic,
this patch tries to add a generic cpufreq driver layer for all big LITTLE
platforms.

The driver is divided into two parts:
- Core driver: Generic and shared across all big LITTLE SoC's
- Glue drivers: Per platform drivers providing ops to the core driver

This patch adds in a generic glue driver which would extract information from
Device Tree.

Future SoC's can either reuse the DT glue or write their own depending on the
need.
Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Some assignments of policy-> min/max/cur/cpuinfo.min_freq/cpuinfo.max_freq
aren't required as part of it is done by cpufreq driver or cpufreq core.

Remove them.

At some places we merge multiple lines together too.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Cpufreq core checks the range of target_freq before calling driver->target() and
so we don't need to do it again.

Remove it.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq layer doesn't call cpufreq driver's callback for any offline
CPU and so checking that isn't useful.

Lets get rid of it.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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>