Commit Graph

130 Commits

Author SHA1 Message Date
Linus Torvalds bab588fcfb arm-soc: soc-specific updates
This is a larger set of new functionality for the existing SoC families,
 including:
 
 * vt8500 gains support for new CPU cores, notably the Cortex-A9 based wm8850
 * prima2 gains support for the "marco" SoC family, its SMP based cousin
 * tegra gains support for the new Tegra4 (Tegra114) family
 * socfpga now supports a newer version of the hardware including SMP
 * i.mx31 and bcm2835 are now using DT probing for their clocks
 * lots of updates for sh-mobile
 * OMAP updates for clocks, power management and USB
 * i.mx6q and tegra now support cpuidle
 * kirkwood now supports PCIe hot plugging
 * tegra clock support is updated
 * tegra USB PHY probing gets implemented diffently
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Merge tag 'soc' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc

Pull ARM SoC-specific updates from Arnd Bergmann:
 "This is a larger set of new functionality for the existing SoC
  families, including:

   - vt8500 gains support for new CPU cores, notably the Cortex-A9 based
     wm8850

   - prima2 gains support for the "marco" SoC family, its SMP based
     cousin

   - tegra gains support for the new Tegra4 (Tegra114) family

   - socfpga now supports a newer version of the hardware including SMP

   - i.mx31 and bcm2835 are now using DT probing for their clocks

   - lots of updates for sh-mobile

   - OMAP updates for clocks, power management and USB

   - i.mx6q and tegra now support cpuidle

   - kirkwood now supports PCIe hot plugging

   - tegra clock support is updated

   - tegra USB PHY probing gets implemented diffently"

* tag 'soc' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (148 commits)
  ARM: prima2: remove duplicate v7_invalidate_l1
  ARM: shmobile: r8a7779: Correct TMU clock support again
  ARM: prima2: fix __init section for cpu hotplug
  ARM: OMAP: Consolidate OMAP USB-HS platform data (part 3/3)
  ARM: OMAP: Consolidate OMAP USB-HS platform data (part 1/3)
  arm: socfpga: Add SMP support for actual socfpga harware
  arm: Add v7_invalidate_l1 to cache-v7.S
  arm: socfpga: Add entries to enable make dtbs socfpga
  arm: socfpga: Add new device tree source for actual socfpga HW
  ARM: tegra: sort Kconfig selects for Tegra114
  ARM: tegra: enable ARCH_REQUIRE_GPIOLIB for Tegra114
  ARM: tegra: Fix build error w/ ARCH_TEGRA_114_SOC w/o ARCH_TEGRA_3x_SOC
  ARM: tegra: Fix build error for gic update
  ARM: tegra: remove empty tegra_smp_init_cpus()
  ARM: shmobile: Register ARM architected timer
  ARM: MARCO: fix the build issue due to gic-vic-to-irqchip move
  ARM: shmobile: r8a7779: Correct TMU clock support
  ARM: mxs_defconfig: Select CONFIG_DEVTMPFS_MOUNT
  ARM: mxs: decrease mxs_clockevent_device.min_delta_ns to 2 clock cycles
  ARM: mxs: use apbx bus clock to drive the timers on timrotv2
  ...
2013-02-21 15:27:22 -08:00
Andrew Lunn 9cfc94eb0f cpuidle: kirkwood: Move out of mach directory
Move the Kirkwood cpuidle driver out of arch/arm/mach-kirkwood and
into drivers/cpuidle. Convert the driver into a platform driver.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
2013-01-31 17:01:37 +00:00
Paul Gortmaker 43720bd601 PM / tracing: remove deprecated power trace API
The text in Documentation said it would be removed in 2.6.41;
the text in the Kconfig said removal in the 3.1 release.  Either
way you look at it, we are well past both, so push it off a cliff.

Note that the POWER_CSTATE and the POWER_PSTATE are part of the
legacy tracing API.  Remove all tracepoints which use these flags.
As can be seen from context, most already have a trace entry via
trace_cpu_idle anyways.

Also, the cpufreq/cpufreq.c PSTATE one is actually unpaired, as
compared to the CSTATE ones which all have a clear start/stop.
As part of this, the trace_power_frequency also becomes orphaned,
so it too is deleted.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-01-26 00:39:12 +01:00
Daniel Lezcano 8aef33a7cf cpuidle: remove the power_specified field in the driver
We realized that the power usage field is never filled and when it
is filled for tegra, the power_specified flag is not set causing all
of these values to be reset when the driver is initialized with
set_power_state().

However, the power_specified flag can be simply removed under the
assumption that the states are always backward sorted, which is the
case with the current code.

This change allows the menu governor select function and the
cpuidle_play_dead() to be simplified.  Moreover, the
set_power_states() function can removed as it does not make sense
any more.

Drop the power_specified flag from struct cpuidle_driver and make
the related changes as described above.

As a consequence, this also fixes the bug where on the dynamic
C-states system, the power fields are not initialized.

[rjw: Changelog]
References: https://bugzilla.kernel.org/show_bug.cgi?id=42870
References: https://bugzilla.kernel.org/show_bug.cgi?id=43349
References: https://lkml.org/lkml/2012/10/16/518
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-01-15 14:18:04 +01:00
Krzysztof Mazur 392370e7aa cpuidle: fix number of initialized/destroyed states
Commit bf4d1b5ddb (cpuidle: support
multiple drivers) changed the number of initialized state kobjects
in cpuidle_add_state_sysfs() from device->state_count to
drv->state_count, but left device->state_count in
cpuidle_remove_state_sysfs().  The values of these two fields may be
different, in which case a NULL pointer dereference may happen in
cpuidle_remove_state_sysfs(), for example.  Fix this problem by making
cpuidle_add_state_sysfs() use device->state_count too (which restores
the original behavior of it).

[rjw: Changelog]
Signed-off-by: Krzysztof Mazur <krzysiek@podlesie.net>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-01-11 23:20:09 +01:00
Daniel Lezcano ac34d7c8c8 cpuidle: fix lock contention in the idle path
Commit bf4d1b5 (cpuidle: support multiple drivers) introduced
locking in cpuidle_get_cpu_driver(), which is used in the
idle_call() function.

This leads to a contention problem with a large number of CPUs,
because they all try to run the idle routine at the same time.

The lock can be safely removed because of how is used the cpuidle
API.  Namely, cpuidle_register_driver() is called first, but the
cpuidle idle function is not entered before cpuidle_register_device()
is called, because the cpuidle device is not enabled then. Moreover,
cpuidle_unregister_driver(), which would reset the driver value to
NULL, is not called before cpuidle_unregister_device().

All of the cpuidle drivers use the API in the same way.

In general, a cleanup around the lock is necessary and a proper
refcounting mechanism should be used to ensure the consistency in the
API (for example, cpuidle_unregister_driver() should fail if the
driver's refcount is not 0). However, these modifications will require
some code reorganization and rewrite which will be too intrusive for
a fix.

For this reason, fix the contention problem introduced by commit
bf4d1b5 by simply removing the locking from cpuidle_get_cpu_driver(),
which restores the original behavior of that routine.

[rjw: Changelog.]
Reported-and-tested-by: Russ Anderson <rja@sgi.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-01-03 13:11:06 +01:00
Sivaram Nair 92638e2fac cpuidle / coupled: fix ready counter decrement
The ready_waiting_counts atomic variable is compared against the wrong
online cpu count. The latter is computed incorrectly using logical-OR
instead of bit-OR. This patch fixes that.

Signed-off-by: Sivaram Nair <sivaramn@nvidia.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Colin Cross <ccross@android.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-01-03 13:11:05 +01:00
Sivaram Nair 0e5537b30d cpuidle: Fix finding state with min power_usage
Since cpuidle_state.power_usage is a signed value, use INT_MAX (instead
of -1) to init the local copies so that functions that tries to find
cpuidle states with minimum power usage works correctly even if they use
non-negative values.

Signed-off-by: Sivaram Nair <sivaramn@nvidia.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-01-03 13:11:05 +01:00
Linus Torvalds d027db132b ARM: arm-soc: SoC updates for 3.8
This contains the bulk of new SoC development for this merge window.
 
 Two new platforms have been added, the sunxi platforms (Allwinner A1x
 SoCs) by Maxime Ripard, and a generic Broadcom platform for a new
 series of ARMv7 platforms from them, where the hope is that we can
 keep the platform code generic enough to have them all share one mach
 directory. The new Broadcom platform is contributed by Christian Daudt.
 
 Highbank has grown support for Calxeda's next generation of hardware,
 ECX-2000.
 
 clps711x has seen a lot of cleanup from Alexander Shiyan, and he's also
 taken on maintainership of the platform.
 
 Beyond this there has been a bunch of work from a number of people on
 converting more platforms to IRQ domains, pinctrl conversion, cleanup
 and general feature enablement across most of the active platforms.
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Merge tag 'soc' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc

Pull ARM SoC updates from Olof Johansson:
 "This contains the bulk of new SoC development for this merge window.

  Two new platforms have been added, the sunxi platforms (Allwinner A1x
  SoCs) by Maxime Ripard, and a generic Broadcom platform for a new
  series of ARMv7 platforms from them, where the hope is that we can
  keep the platform code generic enough to have them all share one mach
  directory.  The new Broadcom platform is contributed by Christian
  Daudt.

  Highbank has grown support for Calxeda's next generation of hardware,
  ECX-2000.

  clps711x has seen a lot of cleanup from Alexander Shiyan, and he's
  also taken on maintainership of the platform.

  Beyond this there has been a bunch of work from a number of people on
  converting more platforms to IRQ domains, pinctrl conversion, cleanup
  and general feature enablement across most of the active platforms."

Fix up trivial conflicts as per Olof.

* tag 'soc' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (174 commits)
  mfd: vexpress-sysreg: Remove LEDs code
  irqchip: irq-sunxi: Add terminating entry for sunxi_irq_dt_ids
  clocksource: sunxi_timer: Add terminating entry for sunxi_timer_dt_ids
  irq: versatile: delete dangling variable
  ARM: sunxi: add missing include for mdelay()
  ARM: EXYNOS: Avoid early use of of_machine_is_compatible()
  ARM: dts: add node for PL330 MDMA1 controller for exynos4
  ARM: EXYNOS: Add support for secondary CPU bring-up on Exynos4412
  ARM: EXYNOS: add UART3 to DEBUG_LL ports
  ARM: S3C24XX: Add clkdev entry for camif-upll clock
  ARM: SAMSUNG: Add s3c24xx/s3c64xx CAMIF GPIO setup helpers
  ARM: sunxi: Add missing sun4i.dtsi file
  pinctrl: samsung: Do not initialise statics to 0
  ARM i.MX6: remove gate_mask from pllv3
  ARM i.MX6: Fix ethernet PLL clocks
  ARM i.MX6: rename PLLs according to datasheet
  ARM i.MX6: Add pwm support
  ARM i.MX51: Add pwm support
  ARM i.MX53: Add pwm support
  ARM: mx5: Replace clk_register_clkdev with clock DT lookup
  ...
2012-12-12 12:05:15 -08:00
Julius Werner a474a51549 cpuidle: Measure idle state durations with monotonic clock
Many cpuidle drivers measure their time spent in an idle state by
reading the wallclock time before and after idling and calculating the
difference. This leads to erroneous results when the wallclock time gets
updated by another processor in the meantime, adding that clock
adjustment to the idle state's time counter.

If the clock adjustment was negative, the result is even worse due to an
erroneous cast from int to unsigned long long of the last_residency
variable. The negative 32 bit integer will zero-extend and result in a
forward time jump of roughly four billion milliseconds or 1.3 hours on
the idle state residency counter.

This patch changes all affected cpuidle drivers to either use the
monotonic clock for their measurements or make use of the generic time
measurement wrapper in cpuidle.c, which was already working correctly.
Some superfluous CLIs/STIs in the ACPI code are removed (interrupts
should always already be disabled before entering the idle function, and
not get reenabled until the generic wrapper has performed its second
measurement). It also removes the erroneous cast, making sure that
negative residency values are applied correctly even though they should
not appear anymore.

Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Tested-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Len Brown <len.brown@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-27 14:17:58 +01:00
Li Zhong a093b93ee0 cpuidle: fix a suspicious RCU usage in menu governor
I saw this suspicious RCU usage on the next tree of 11/15

[   67.123404] ===============================
[   67.123413] [ INFO: suspicious RCU usage. ]
[   67.123423] 3.7.0-rc5-next-20121115-dirty #1 Not tainted
[   67.123434] -------------------------------
[   67.123444] include/trace/events/timer.h:186 suspicious rcu_dereference_check() usage!
[   67.123458]
[   67.123458] other info that might help us debug this:
[   67.123458]
[   67.123474]
[   67.123474] RCU used illegally from idle CPU!
[   67.123474] rcu_scheduler_active = 1, debug_locks = 0
[   67.123493] RCU used illegally from extended quiescent state!
[   67.123507] 1 lock held by swapper/1/0:
[   67.123516]  #0:  (&cpu_base->lock){-.-...}, at: [<c0000000000979b0>] .__hrtimer_start_range_ns+0x28c/0x524
[   67.123555]
[   67.123555] stack backtrace:
[   67.123566] Call Trace:
[   67.123576] [c0000001e2ccb920] [c00000000001275c] .show_stack+0x78/0x184 (unreliable)
[   67.123599] [c0000001e2ccb9d0] [c0000000000c15a0] .lockdep_rcu_suspicious+0x120/0x148
[   67.123619] [c0000001e2ccba70] [c00000000009601c] .enqueue_hrtimer+0x1c0/0x1c8
[   67.123639] [c0000001e2ccbb00] [c000000000097aa0] .__hrtimer_start_range_ns+0x37c/0x524
[   67.123660] [c0000001e2ccbc20] [c0000000005c9698] .menu_select+0x508/0x5bc
[   67.123678] [c0000001e2ccbd20] [c0000000005c740c] .cpuidle_idle_call+0xa8/0x6e4
[   67.123699] [c0000001e2ccbdd0] [c0000000000459a0] .pSeries_idle+0x10/0x34
[   67.123717] [c0000001e2ccbe40] [c000000000014dc8] .cpu_idle+0x130/0x280
[   67.123738] [c0000001e2ccbee0] [c0000000006ffa8c] .start_secondary+0x378/0x384
[   67.123758] [c0000001e2ccbf90] [c00000000000936c] .start_secondary_prolog+0x10/0x14

hrtimer_start was added in 198fd638 and ae515197. The patch below tries
to use RCU_NONIDLE around it to avoid the above report.

Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-23 00:05:03 +01:00
Daniel Lezcano bf4d1b5ddb cpuidle: support multiple drivers
With the tegra3 and the big.LITTLE [1] new architectures, several cpus
with different characteristics (latencies and states) can co-exists on the
system.

The cpuidle framework has the limitation of handling only identical cpus.

This patch removes this limitation by introducing the multiple driver support
for cpuidle.

This option is configurable at compile time and should be enabled for the
architectures mentioned above. So there is no impact for the other platforms
if the option is disabled. The option defaults to 'n'. Note the multiple drivers
support is also compatible with the existing drivers, even if just one driver is
needed, all the cpu will be tied to this driver using an extra small chunk of
processor memory.

The multiple driver support use a per-cpu driver pointer instead of a global
variable and the accessor to this variable are done from a cpu context.

In order to keep the compatibility with the existing drivers, the function
'cpuidle_register_driver' and 'cpuidle_unregister_driver' will register
the specified driver for all the cpus.

The semantic for the output of /sys/devices/system/cpu/cpuidle/current_driver
remains the same except the driver name will be related to the current cpu.

The /sys/devices/system/cpu/cpu[0-9]/cpuidle/driver/name files are added
allowing to read the per cpu driver name.

[1] http://lwn.net/Articles/481055/

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-15 00:34:23 +01:00
Daniel Lezcano 13dd52f11a cpuidle: prepare the cpuidle core to handle multiple drivers
This patch is a preparation for the multiple cpuidle drivers support.

As the next patch will introduce the multiple drivers with the Kconfig
option and we want to keep the code clean and understandable, this patch
defines a set of functions for encapsulating some common parts and splits
what should be done under a lock from the rest.

[rjw: Modified the subject and changelog slightly.]
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-15 00:34:22 +01:00
Daniel Lezcano 4168203271 cpuidle: move driver checking within the lock section
The code is racy and the check with cpuidle_curr_driver should be
done under the lock.

I don't find a path in the different drivers where that could happen
because the arch specific drivers are written in such way it is not
possible to register a driver while it is unregistered, except maybe
in a very improbable case when "intel_idle" and "processor_idle" are
competing. One could unregister a driver, while the other one is
registering.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-15 00:34:22 +01:00
Daniel Lezcano 42f67f2aca cpuidle: move driver's refcount to cpuidle
We want to support different cpuidle drivers co-existing together.
In this case we should move the refcount to the cpuidle_driver
structure to handle several drivers at a time.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-15 00:34:22 +01:00
Daniel Lezcano 8f3e9953e1 cpuidle: fixup device.h header in cpuidle.h
The "struct device" is only used in sysfs.c.

The other .c files including the private header "cpuidle.h"
do not need to pull the entire headers tree from there as they
don't manipulate the "struct device".

This patch fixes this by moving the header inclusion to sysfs.c
and adding a forward declaration for the struct device.

The number of lines generated by the preprocesor:
Without this patch : 17269 loc
With this patch : 16446 loc

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-15 00:34:21 +01:00
Daniel Lezcano 349631e0e4 cpuidle / sysfs: move structure declaration into the sysfs.c file
The structure cpuidle_state_kobj is not used anywhere except
in the sysfs.c file. The definition of this structure is not
needed in the cpuidle header file. This patch moves it to the
sysfs.c file in order to encapsulate the code a bit more.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-15 00:34:21 +01:00
Youquan Song c96ca4fb76 cpuidle: Get typical recent sleep interval
The function detect_repeating_patterns was not very useful for
workloads with alternating long and short pauses, for example
virtual machines handling network requests for each other (say
a web and database server).

Instead, try to find a recent sleep interval that is somewhere
between the median and the mode sleep time, by discarding outliers
to the up side and recalculating the average and standard deviation
until that is no longer required.

This should do something sane with a sleep interval series like:

	200 180 210 10000 30 1000 170 200

The current code would simply discard such a series, while the
new code will guess a typical sleep interval just shy of 200.

The original patch come from Rik van Riel <riel@redhat.com>.

Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Youquan Song <youquan.song@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-15 00:34:20 +01:00
Youquan Song d73d68dc49 cpuidle: Set residency to 0 if target Cstate not enter
When cpuidle governor choose a C-state to enter for idle CPU, but it notice that
there is tasks request to be executed. So the idle CPU will not really enter
the target C-state and go to run task.

In this situation, it will use the residency of previous really entered target
C-states. Obviously, it is not reasonable.

So, this patch fix it by set the target C-state residency to 0.

Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Youquan Song <youquan.song@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-15 00:34:20 +01:00
Youquan Song e11538d1f0 cpuidle: Quickly notice prediction failure in general case
The prediction for future is difficult and when the cpuidle governor prediction
fails and govenor possibly choose the shallower C-state than it should. How to
quickly notice and find the failure becomes important for power saving.

The patch extends to general case that prediction logic get a small predicted
residency, so it choose a shallow C-state though the expected residency is large
. Once the prediction will be fail, the CPU will keep staying at shallow C-state
for a long time. Acutally, the CPU has change enter into deep C-state.
So when the expected residency is long enough but governor choose a shallow
C-state, an timer will be added in order to monitor if the prediction failure.

When C-state is waken up prior to the adding timer, the timer will be cancelled
initiatively. When the timer is triggered and menu governor will quickly notice
prediction failure and re-evaluates deeper C-states possibility.

Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Youquan Song <youquan.song@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-15 00:34:20 +01:00
Youquan Song 69a37beabf cpuidle: Quickly notice prediction failure for repeat mode
The prediction for future is difficult and when the cpuidle governor prediction
fails and govenor possibly choose the shallower C-state than it should. How to
quickly notice and find the failure becomes important for power saving.

cpuidle menu governor has a method to predict the repeat pattern if there are 8
C-states residency which are continuous and the same or very close, so it will
predict the next C-states residency will keep same residency time.

There is a real case that turbostat utility (tools/power/x86/turbostat)
at kernel 3.3 or early. turbostat utility will read 10 registers one by one at
Sandybridge, so it will generate 10 IPIs to wake up idle CPUs. So cpuidle menu
 governor will predict it is repeat mode and there is another IPI wake up idle
 CPU soon, so it keeps idle CPU stay at C1 state even though CPU is totally
idle. However, in the turbostat, following 10 registers reading is sleep 5
seconds by default, so the idle CPU will keep at C1 for a long time though it is
 idle until break event occurs.
In a idle Sandybridge system, run "./turbostat -v", we will notice that deep
C-state dangles between "70% ~ 99%". After patched the kernel, we will notice
deep C-state stays at >99.98%.

In the patch, a timer is added when menu governor detects a repeat mode and
choose a shallow C-state. The timer is set to a time out value that greater
than predicted time, and we conclude repeat mode prediction failure if timer is
triggered. When repeat mode happens as expected, the timer is not triggered
and CPU waken up from C-states and it will cancel the timer initiatively.
When repeat mode does not happen, the timer will be time out and menu governor
will quickly notice that the repeat mode prediction fails and then re-evaluates
deeper C-states possibility.

Below is another case which will clearly show the patch much benefit:

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <signal.h>
#include <sys/time.h>
#include <time.h>
#include <pthread.h>

volatile int * shutdown;
volatile long * count;
int delay = 20;
int loop = 8;

void usage(void)
{
	fprintf(stderr,
		"Usage: idle_predict [options]\n"
		"  --help	-h  Print this help\n"
		"  --thread	-n  Thread number\n"
		"  --loop     	-l  Loop times in shallow Cstate\n"
		"  --delay	-t  Sleep time (uS)in shallow Cstate\n");
}

void *simple_loop() {
	int idle_num = 1;
	while (!(*shutdown)) {
		*count = *count + 1;

		if (idle_num % loop)
			usleep(delay);
		else {
			/* sleep 1 second */
			usleep(1000000);
			idle_num = 0;
		}
		idle_num++;
	}

}

static void sighand(int sig)
{
	*shutdown = 1;
}

int main(int argc, char *argv[])
{
	sigset_t sigset;
	int signum = SIGALRM;
	int i, c, er = 0, thread_num = 8;
	pthread_t pt[1024];

	static char optstr[] = "n:l:t:h:";

	while ((c = getopt(argc, argv, optstr)) != EOF)
		switch (c) {
			case 'n':
				thread_num = atoi(optarg);
				break;
			case 'l':
				loop = atoi(optarg);
				break;
			case 't':
				delay = atoi(optarg);
				break;
			case 'h':
			default:
				usage();
				exit(1);
		}

	printf("thread=%d,loop=%d,delay=%d\n",thread_num,loop,delay);
	count = malloc(sizeof(long));
	shutdown = malloc(sizeof(int));
	*count = 0;
	*shutdown = 0;

	sigemptyset(&sigset);
	sigaddset(&sigset, signum);
	sigprocmask (SIG_BLOCK, &sigset, NULL);
	signal(SIGINT, sighand);
	signal(SIGTERM, sighand);

	for(i = 0; i < thread_num ; i++)
		pthread_create(&pt[i], NULL, simple_loop, NULL);

	for (i = 0; i < thread_num; i++)
		pthread_join(pt[i], NULL);

	exit(0);
}

Get powertop V2 from git://github.com/fenrus75/powertop, build powertop.
After build the above test application, then run it.
Test plaform can be Intel Sandybridge or other recent platforms.
#./idle_predict -l 10 &
#./powertop

We will find that deep C-state will dangle between 40%~100% and much time spent
on C1 state. It is because menu governor wrongly predict that repeat mode
is kept, so it will choose the C1 shallow C-state even though it has chance to
sleep 1 second in deep C-state.

While after patched the kernel, we find that deep C-state will keep >99.6%.

Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Youquan Song <youquan.song@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-15 00:34:19 +01:00
Daniel Lezcano e45a00d679 cpuidle / sysfs: move kobj initialization in the syfs file
Move the kobj initialization and completion in the sysfs.c
and encapsulate the code more.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-15 00:34:19 +01:00
Daniel Lezcano 1aef40e288 cpuidle / sysfs: change function parameter
The function needs the cpuidle_device which is initially passed to the
caller.

The current code gets the struct device from the struct cpuidle_device,
pass it the cpuidle_add_sysfs function. This function calls
per_cpu(cpuidle_devices, cpu) to get the cpuidle_device.

This patch pass the cpuidle_device instead and simplify the code.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-15 00:34:19 +01:00
Rob Herring be6a98d3f0 cpuidle: add Calxeda SOC idle support
Add support for core powergating on Calxeda platforms. Initially, this
supports ECX-1000 (highbank), but support will be added for ECX-2000
later.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Cc: Len Brown <len.brown@intel.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
2012-11-07 17:15:36 -06:00
Srivatsa S. Bhat cf31cd1a0c ACPI idle, CPU hotplug: Fix NULL pointer dereference during hotplug
On a KVM guest, when a CPU is taken offline and brought back online, we hit
the following NULL pointer dereference:

[   45.400843] Unregister pv shared memory for cpu 1
[   45.412331] smpboot: CPU 1 is now offline
[   45.529894] SMP alternatives: lockdep: fixing up alternatives
[   45.533472] smpboot: Booting Node 0 Processor 1 APIC 0x1
[   45.411526] kvm-clock: cpu 1, msr 0:7d14601, secondary cpu clock
[   45.571370] KVM setup async PF for cpu 1
[   45.572331] kvm-stealtime: cpu 1, msr 7d0e040
[   45.575031] BUG: unable to handle kernel NULL pointer dereference at           (null)
[   45.576017] IP: [<ffffffff81519f98>] cpuidle_disable_device+0x18/0x80
[   45.576017] PGD 5dfb067 PUD 5da8067 PMD 0
[   45.576017] Oops: 0000 [#1] SMP
[   45.576017] Modules linked in:
[   45.576017] CPU 0
[   45.576017] Pid: 607, comm: stress_cpu_hotp Not tainted 3.6.0-padata-tp-debug #3 Bochs Bochs
[   45.576017] RIP: 0010:[<ffffffff81519f98>]  [<ffffffff81519f98>] cpuidle_disable_device+0x18/0x80
[   45.576017] RSP: 0018:ffff880005d93ce8  EFLAGS: 00010286
[   45.576017] RAX: ffff880005d93fd8 RBX: 0000000000000000 RCX: 0000000000000006
[   45.576017] RDX: 0000000000000006 RSI: 2222222222222222 RDI: 0000000000000000
[   45.576017] RBP: ffff880005d93cf8 R08: 2222222222222222 R09: 2222222222222222
[   45.576017] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
[   45.576017] R13: 0000000000000000 R14: ffffffff81c8cca0 R15: 0000000000000001
[   45.576017] FS:  00007f91936ae700(0000) GS:ffff880007c00000(0000) knlGS:0000000000000000
[   45.576017] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[   45.576017] CR2: 0000000000000000 CR3: 0000000005db3000 CR4: 00000000000006f0
[   45.576017] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   45.576017] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[   45.576017] Process stress_cpu_hotp (pid: 607, threadinfo ffff880005d92000, task ffff8800066bbf40)
[   45.576017] Stack:
[   45.576017]  ffff880007a96400 0000000000000000 ffff880005d93d28 ffffffff813ac689
[   45.576017]  ffff880007a96400 ffff880007a96400 0000000000000002 ffffffff81cd8d01
[   45.576017]  ffff880005d93d58 ffffffff813aa498 0000000000000001 00000000ffffffdd
[   45.576017] Call Trace:
[   45.576017]  [<ffffffff813ac689>] acpi_processor_hotplug+0x55/0x97
[   45.576017]  [<ffffffff813aa498>] acpi_cpu_soft_notify+0x93/0xce
[   45.576017]  [<ffffffff816ae47d>] notifier_call_chain+0x5d/0x110
[   45.576017]  [<ffffffff8109730e>] __raw_notifier_call_chain+0xe/0x10
[   45.576017]  [<ffffffff81069050>] __cpu_notify+0x20/0x40
[   45.576017]  [<ffffffff81069085>] cpu_notify+0x15/0x20
[   45.576017]  [<ffffffff816978f1>] _cpu_up+0xee/0x137
[   45.576017]  [<ffffffff81697983>] cpu_up+0x49/0x59
[   45.576017]  [<ffffffff8168758d>] store_online+0x9d/0xe0
[   45.576017]  [<ffffffff8140a9f8>] dev_attr_store+0x18/0x30
[   45.576017]  [<ffffffff812322c0>] sysfs_write_file+0xe0/0x150
[   45.576017]  [<ffffffff811b389c>] vfs_write+0xac/0x180
[   45.576017]  [<ffffffff811b3be2>] sys_write+0x52/0xa0
[   45.576017]  [<ffffffff816b31e9>] system_call_fastpath+0x16/0x1b
[   45.576017] Code: 48 c7 c7 40 e5 ca 81 e8 07 d0 18 00 5d c3 0f 1f 44 00 00 0f 1f 44 00 00 55 48 89 e5 48 83 ec 10 48 89 5d f0 4c 89 65 f8 48 89 fb <f6> 07 02 75 13 48 8b 5d f0 4c 8b 65 f8 c9 c3 66 0f 1f 84 00 00
[   45.576017] RIP  [<ffffffff81519f98>] cpuidle_disable_device+0x18/0x80
[   45.576017]  RSP <ffff880005d93ce8>
[   45.576017] CR2: 0000000000000000
[   45.656079] ---[ end trace 433d6c9ac0b02cef ]---

Analysis:
Commit 3d339dc (cpuidle / ACPI : move cpuidle_device field out of the
acpi_processor_power structure()) made the allocation of the dev structure
(struct cpuidle) of a CPU dynamic, whereas previously it was statically
allocated. And this dynamic allocation occurs in acpi_processor_power_init()
if pr->flags.power evaluates to non-zero.

On KVM guests, pr->flags.power evaluates to zero, hence dev is never
allocated. This causes the NULL pointer (dev) dereference in
cpuidle_disable_device() during a subsequent CPU online operation. Fix this
by ensuring that dev is non-NULL before dereferencing.

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2012-10-08 22:52:54 -04:00
Daniel Lezcano ed953472d1 cpuidle: rename function name "__cpuidle_register_driver", v2
The function __cpuidle_register_driver name is confusing because it
suggests, conforming to the coding style of the kernel, it registers
the driver without taking a lock. Actually, it just fill the different
power field states with a decresing value if the power has not been
specified.

Clarify the purpose of the function by changing its name and
move the condition out of this function.

This patch fix nothing and does not change the behavior of the
function. It is just for the sake of clarity.

IHMO, reading in the code:

+       if (!drv->power_specified)
+               set_power_states(drv);

is much more explicit than:

-       __cpuidle_register_driver(drv);

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-09-22 00:38:32 +02:00
Daniel Lezcano a77de28662 cpuidle: remove some empty lines
This mindless patch is just about removing some trailing
carriage returns.

[rjw: Changed the subject.]

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-09-19 21:59:42 +02:00
Rafael J. Wysocki 66804c13f7 PM / cpuidle: Make ladder governor use the "disabled" state flag
For the mechanism introduced by commit cbc9ef0 (PM / Domains: Add
preliminary support for cpuidle, v2) to work with the ladder
governor, that governor should respect the "disabled" state flag
added by that commit.  Change the ladder governor accordingly.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-09-04 01:35:45 +02:00
Carsten Emde 62d6ae880e Honor state disabling in the cpuidle ladder governor
There are two cpuidle governors ladder and menu. While the ladder
governor is always available, if CONFIG_CPU_IDLE is selected, the
menu governor additionally requires CONFIG_NO_HZ.

A particular C state can be disabled by writing to the sysfs file
/sys/devices/system/cpu/cpuN/cpuidle/stateN/disable, but this mechanism
is only implemented in the menu governor. Thus, in a system where
CONFIG_NO_HZ is not selected, the ladder governor becomes default and
always will walk through all sleep states - irrespective of whether the
C state was disabled via sysfs or not. The only way to select a specific
C state was to write the related latency to /dev/cpu_dma_latency and
keep the file open as long as this setting was required - not very
practical and not suitable for setting a single core in an SMP system.

With this patch, the ladder governor only will promote to the next
C state, if it has not been disabled, and it will demote, if the
current C state was disabled.

Note that the patch does not make the setting of the sysfs variable
"disable" coherent, i.e. if one is disabling a light state, then all
deeper states are disabled as well, but the "disable" variable does not
reflect it. Likewise, if one enables a deep state but a lighter state
still is disabled, then this has no effect. A related section has been
added to the documentation.

Signed-off-by: Carsten Emde <C.Emde@osadl.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-09-04 01:35:44 +02:00
Jon Medhurst (Tixy) 5fbbb90dfd cpuidle: Prevent null pointer dereference in cpuidle_coupled_cpu_notify
When a kernel is built to support multiple hardware types it's possible
that CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED is set but the hardware the
kernel is run on doesn't support cpuidle and therefore doesn't load a
driver for it. In this case, when the system is shut down,
cpuidle_coupled_cpu_notify() gets called with cpuidle_devices set to
NULL. There are quite possibly other circumstances where this
situation can also occur and we should check for it.

Signed-off-by: Jon Medhurst <tixy@linaro.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-08-17 19:37:08 +02:00
Colin Cross 63c6ba4352 cpuidle: coupled: fix sleeping while atomic in cpu notifier
The cpu hotplug notifier gets called in both atomic and non-atomic
contexts, it is not always safe to lock a mutex.  Filter out all events
except the six necessary ones, which are all sleepable, before taking
the mutex.

Signed-off-by: Colin Cross <ccross@android.com>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-08-17 19:37:01 +02:00
Linus Torvalds 476525004a Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux
Pull ACPI & power management update from Len Brown:
 "Re-write of the turbostat tool.
     lower overhead was necessary for measuring very large system when
     they are very idle.

  IVB support in intel_idle
     It's what I run on my IVB, others should be able to also:-)

  ACPICA core update
     We have found some bugs due to divergence between Linux and the
     upstream ACPICA base.  Most of these patches are to reduce that
     divergence to reduce the risk of future bugs.

  Some cpuidle updates, mostly for non-Intel
     More will be coming, as they depend on this part.

  Some thermal management changes needed by non-ACPI systems.

  Some _OST (OS Status Indication) updates for hot ACPI hot-plug."

* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux: (51 commits)
  Thermal: Documentation update
  Thermal: Add Hysteresis attributes
  Thermal: Make Thermal trip points writeable
  ACPI/AC: prevent OOPS on some boxes due to missing check power_supply_register() return value check
  tools/power: turbostat: fix large c1% issue
  tools/power: turbostat v2 - re-write for efficiency
  ACPICA: Update to version 20120711
  ACPICA: AcpiSrc: Fix some translation issues for Linux conversion
  ACPICA: Update header files copyrights to 2012
  ACPICA: Add new ACPI table load/unload external interfaces
  ACPICA: Split file: tbxface.c -> tbxfload.c
  ACPICA: Add PCC address space to space ID decode function
  ACPICA: Fix some comment fields
  ACPICA: Table manager: deploy new firmware error/warning interfaces
  ACPICA: Add new interfaces for BIOS(firmware) errors and warnings
  ACPICA: Split exception code utilities to a new file, utexcep.c
  ACPI: acpi_pad: tune round_robin_time
  ACPICA: Update to version 20120620
  ACPICA: Add support for implicit notify on multiple devices
  ACPICA: Update comments; no functional change
  ...
2012-07-26 14:28:55 -07:00
Len Brown ec033d0a02 Merge branches 'acpi_pad', 'acpica', 'apei-bugzilla-43282', 'battery', 'cpuidle-coupled', 'cpuidle-tweaks', 'intel_idle-ivb', 'ost', 'red-hat-bz-772730', 'thermal', 'thermal-spear' and 'turbostat-v2' into release 2012-07-26 00:03:58 -04:00
Rafael J. Wysocki 7791bd230c Merge branch 'pm-domains'
* pm-domains:
  PM / Domains: Fix build warning for CONFIG_PM_RUNTIME unset
  PM / Domains: Replace plain integer with NULL pointer in domain.c file
  PM / Domains: Add missing static storage class specifier in domain.c file
  PM / Domains: Allow device callbacks to be added at any time
  PM / Domains: Add device domain data reference counter
  PM / Domains: Add preliminary support for cpuidle, v2
  PM / Domains: Do not stop devices after restoring their states
  PM / Domains: Use subsystem runtime suspend/resume callbacks by default
2012-07-19 00:03:17 +02:00
Preeti U Murthy 8651f97bd9 PM / cpuidle: System resume hang fix with cpuidle
On certain bios, resume hangs if cpus are allowed to enter idle states
during suspend [1].

This was fixed in apci idle driver [2].But intel_idle driver does not
have this fix. Thus instead of replicating the fix in both the idle
drivers, or in more platform specific idle drivers if needed, the
more general cpuidle infrastructure could handle this.

A suspend callback in cpuidle_driver could handle this fix. But
a cpuidle_driver provides only basic functionalities like platform idle
state detection capability and mechanisms to support entry and exit
into CPU idle states. All other cpuidle functions are found in the
cpuidle generic infrastructure for good reason that all cpuidle
drivers, irrepective of their platforms will support these functions.

One option therefore would be to register a suspend callback in cpuidle
which handles this fix. This could be called through a PM_SUSPEND_PREPARE
notifier. But this is too generic a notfier for a driver to handle.

Also, ideally the job of cpuidle is not to handle side effects of suspend.
It should expose the interfaces which "handle cpuidle 'during' suspend"
or any other operation, which the subsystems call during that respective
operation.

The fix demands that during suspend, no cpus should be allowed to enter
deep C-states. The interface cpuidle_uninstall_idle_handler() in cpuidle
ensures that. Not just that it also kicks all the cpus which are already
in idle out of their idle states which was being done during cpu hotplug
through a CPU_DYING_FROZEN callbacks.

Now the question arises about when during suspend should
cpuidle_uninstall_idle_handler() be called. Since we are dealing with
drivers it seems best to call this function during dpm_suspend().
Delaying the call till dpm_suspend_noirq() does no harm, as long as it is
before cpu_hotplug_begin() to avoid race conditions with cpu hotpulg
operations. In dpm_suspend_noirq(), it would be wise to place this call
before suspend_device_irqs() to avoid ugly interactions with the same.

Ananlogously, during resume.

References:
[1] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/674075.
[2] http://marc.info/?l=linux-pm&m=133958534231884&w=2

Reported-and-tested-by: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-07-10 21:34:49 +02:00
Rafael J. Wysocki cbc9ef0287 PM / Domains: Add preliminary support for cpuidle, v2
On some systems there are CPU cores located in the same power
domains as I/O devices.  Then, power can only be removed from the
domain if all I/O devices in it are not in use and the CPU core
is idle.  Add preliminary support for that to the generic PM domains
framework.

First, the platform is expected to provide a cpuidle driver with one
extra state designated for use with the generic PM domains code.
This state should be initially disabled and its exit_latency value
should be set to whatever time is needed to bring up the CPU core
itself after restoring power to it, not including the domain's
power on latency.  Its .enter() callback should point to a procedure
that will remove power from the domain containing the CPU core at
the end of the CPU power transition.

The remaining characteristics of the extra cpuidle state, referred to
as the "domain" cpuidle state below, (e.g. power usage, target
residency) should be populated in accordance with the properties of
the hardware.

Next, the platform should execute genpd_attach_cpuidle() on the PM
domain containing the CPU core.  That will cause the generic PM
domains framework to treat that domain in a special way such that:

 * When all devices in the domain have been suspended and it is about
   to be turned off, the states of the devices will be saved, but
   power will not be removed from the domain.  Instead, the "domain"
   cpuidle state will be enabled so that power can be removed from
   the domain when the CPU core is idle and the state has been chosen
   as the target by the cpuidle governor.

 * When the first I/O device in the domain is resumed and
   __pm_genpd_poweron(() is called for the first time after
   power has been removed from the domain, the "domain" cpuidle
   state will be disabled to avoid subsequent surprise power removals
   via cpuidle.

The effective exit_latency value of the "domain" cpuidle state
depends on the time needed to bring up the CPU core itself after
restoring power to it as well as on the power on latency of the
domain containing the CPU core.  Thus the "domain" cpuidle state's
exit_latency has to be recomputed every time the domain's power on
latency is updated, which may happen every time power is restored
to the domain, if the measured power on latency is greater than
the latency stored in the corresponding generic_pm_domain structure.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: Kevin Hilman <khilman@ti.com>
2012-07-03 19:07:42 +02:00
Rafael J. Wysocki 6e797a0788 PM / cpuidle: Add driver reference counter
Add a reference counter for the cpuidle driver, so that it can't
be unregistered when it is in use.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-07-03 19:06:25 +02:00
ShuoX Liu dc7fd275ae cpuidle: move field disable from per-driver to per-cpu
Andrew J.Schorr raises a question.  When he changes the disable setting on
a single CPU, it affects all the other CPUs.  Basically, currently, the
disable field is per-driver instead of per-cpu.  All the C states of the
same driver are shared by all CPU in the same machine.

The patch changes the `disable' field to per-cpu, so we could set this
separately for each cpu.

Signed-off-by: ShuoX Liu <shuox.liu@intel.com>
Reported-by: Andrew J.Schorr <aschorr@telemetry-investments.com>
Reviewed-by: Yanmin Zhang <yanmin_zhang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-07-03 19:05:31 +02:00
Colin Cross 20ff51a36b cpuidle: coupled: add parallel barrier function
Adds cpuidle_coupled_parallel_barrier, which can be used by coupled
cpuidle state enter functions to handle resynchronization after
determining if any cpu needs to abort.  The normal use case will
be:

static bool abort_flag;
static atomic_t abort_barrier;

int arch_cpuidle_enter(struct cpuidle_device *dev, ...)
{
	if (arch_turn_off_irq_controller()) {
	   	/* returns an error if an irq is pending and would be lost
		   if idle continued and turned off power */
		abort_flag = true;
	}

	cpuidle_coupled_parallel_barrier(dev, &abort_barrier);

	if (abort_flag) {
	   	/* One of the cpus didn't turn off it's irq controller */
	   	arch_turn_on_irq_controller();
		return -EINTR;
	}

	/* continue with idle */
	...
}

This will cause all cpus to abort idle together if one of them needs
to abort.

Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2012-06-02 00:49:36 -04:00
Colin Cross 4126c0197b cpuidle: add support for states that affect multiple cpus
On some ARM SMP SoCs (OMAP4460, Tegra 2, and probably more), the
cpus cannot be independently powered down, either due to
sequencing restrictions (on Tegra 2, cpu 0 must be the last to
power down), or due to HW bugs (on OMAP4460, a cpu powering up
will corrupt the gic state unless the other cpu runs a work
around).  Each cpu has a power state that it can enter without
coordinating with the other cpu (usually Wait For Interrupt, or
WFI), and one or more "coupled" power states that affect blocks
shared between the cpus (L2 cache, interrupt controller, and
sometimes the whole SoC).  Entering a coupled power state must
be tightly controlled on both cpus.

The easiest solution to implementing coupled cpu power states is
to hotplug all but one cpu whenever possible, usually using a
cpufreq governor that looks at cpu load to determine when to
enable the secondary cpus.  This causes problems, as hotplug is an
expensive operation, so the number of hotplug transitions must be
minimized, leading to very slow response to loads, often on the
order of seconds.

This file implements an alternative solution, where each cpu will
wait in the WFI state until all cpus are ready to enter a coupled
state, at which point the coupled state function will be called
on all cpus at approximately the same time.

Once all cpus are ready to enter idle, they are woken by an smp
cross call.  At this point, there is a chance that one of the
cpus will find work to do, and choose not to enter idle.  A
final pass is needed to guarantee that all cpus will call the
power state enter function at the same time.  During this pass,
each cpu will increment the ready counter, and continue once the
ready counter matches the number of online coupled cpus.  If any
cpu exits idle, the other cpus will decrement their counter and
retry.

To use coupled cpuidle states, a cpuidle driver must:

   Set struct cpuidle_device.coupled_cpus to the mask of all
   coupled cpus, usually the same as cpu_possible_mask if all cpus
   are part of the same cluster.  The coupled_cpus mask must be
   set in the struct cpuidle_device for each cpu.

   Set struct cpuidle_device.safe_state to a state that is not a
   coupled state.  This is usually WFI.

   Set CPUIDLE_FLAG_COUPLED in struct cpuidle_state.flags for each
   state that affects multiple cpus.

   Provide a struct cpuidle_state.enter function for each state
   that affects multiple cpus.  This function is guaranteed to be
   called on all cpus at approximately the same time.  The driver
   should ensure that the cpus all abort together if any cpu tries
   to abort once the function is called.

update1:

cpuidle: coupled: fix count of online cpus

online_count was never incremented on boot, and was also counting
cpus that were not part of the coupled set.  Fix both issues by
introducting a new function that counts online coupled cpus, and
call it from register as well as the hotplug notifier.

update2:

cpuidle: coupled: fix decrementing ready count

cpuidle_coupled_set_not_ready sometimes refuses to decrement the
ready count in order to prevent a race condition.  This makes it
unsuitable for use when finished with idle.  Add a new function
cpuidle_coupled_set_done that decrements both the ready count and
waiting count, and call it after idle is complete.

Cc: Amit Kucheria <amit.kucheria@linaro.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Trinabh Gupta <g.trinabh@gmail.com>
Cc: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Colin Cross <ccross@android.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
2012-06-02 00:49:09 -04:00
Colin Cross 3af272ab75 cpuidle: fix error handling in __cpuidle_register_device
Fix the error handling in __cpuidle_register_device to include
the missing list_del.  Move it to a label, which will simplify
the error handling when coupled states are added.

Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Colin Cross <ccross@android.com>
Reviewed-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
2012-06-02 00:48:49 -04:00
Colin Cross 56cfbf74a1 cpuidle: refactor out cpuidle_enter_state
Split the code to enter a state and update the stats into a helper
function, cpuidle_enter_state, and export it.  This function will
be called by the coupled state code to handle entering the safe
state and the final coupled state.

Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Colin Cross <ccross@android.com>
Reviewed-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
2012-06-02 00:48:31 -04:00
Srivatsa S. Bhat 1b0a0e9a15 cpuidle: add checks to avoid NULL pointer dereference
The existing check for dev == NULL in __cpuidle_register_device() is
rendered useless because dev is dereferenced before the check itself.
Moreover, correctly speaking, it is the job of the callers of this
function, i.e., cpuidle_register_device() & cpuidle_enable_device() (which
also happen to be exported functions) to ensure that
__cpuidle_register_device() is called with a non-NULL dev.

So add the necessary dev == NULL checks in the two callers and remove the
(useless) check from __cpuidle_register_device().

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
2012-06-01 16:07:23 -04:00
Sergey Senozhatsky 0aeb9cac6f cpuidle: remove unused hrtimer_peek_ahead_timers() call
commit 9a6558371b
  Author: Arjan van de Ven <arjan@linux.intel.com>
  Date:   Sun Nov 9 12:45:10 2008 -0800

     regression: disable timer peek-ahead for 2.6.28

     It's showing up as regressions; disabling it very likely just papers
     over an underlying issue, but time is running out for 2.6.28, lets get
     back to this for 2.6.29

 Many years has passed since 2008, so it seems ok to remove whole `#if 0' block.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Trinabh Gupta <g.trinabh@gmail.com>
Cc: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
2012-06-01 16:06:48 -04:00
Thomas Gleixner 4a1625133d cpuidle: Use kick_all_cpus_sync()
kick_all_cpus_sync() is the core implementation of cpu_idle_wait()
which is copied all over the arch code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120507175652.119842173@linutronix.de
2012-05-08 12:35:06 +02:00
Len Brown eeaab2d8af Merge branches 'idle-fix' and 'misc' into release 2012-04-06 21:48:59 -04:00
Toshi Kani ee01e66337 cpuidle: Fix panic in CPU off-lining with no idle driver
Fix a NULL pointer dereference panic in cpuidle_play_dead() during
CPU off-lining when no cpuidle driver is registered.  A cpuidle
driver may be registered at boot-time based on CPU type.  This patch
allows an off-lined CPU to enter HLT-based idle in this condition.

Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Cc: Boris Ostrovsky <boris.ostrovsky@amd.com>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Tested-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2012-04-06 15:01:25 -04:00
Linus Torvalds a335750b9a Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux
Pull ACPI & Power Management changes from Len Brown:
 - ACPI 5.0 after-ripples, ACPICA/Linux divergence cleanup
 - cpuidle evolving, more ARM use
 - thermal sub-system evolving, ditto
 - assorted other PM bits

Fix up conflicts in various cpuidle implementations due to ARM cpuidle
cleanups (ARM at91 self-refresh and cpu idle code rewritten into
"standby" in asm conflicting with the consolidation of cpuidle time
keeping), trivial SH include file context conflict and RCU tracing fixes
in generic code.

* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux: (77 commits)
  ACPI throttling: fix endian bug in acpi_read_throttling_status()
  Disable MCP limit exceeded messages from Intel IPS driver
  ACPI video: Don't start video device until its associated input device has been allocated
  ACPI video: Harden video bus adding.
  ACPI: Add support for exposing BGRT data
  ACPI: export acpi_kobj
  ACPI: Fix logic for removing mappings in 'acpi_unmap'
  CPER failed to handle generic error records with multiple sections
  ACPI: Clean redundant codes in scan.c
  ACPI: Fix unprotected smp_processor_id() in acpi_processor_cst_has_changed()
  ACPI: consistently use should_use_kmap()
  PNPACPI: Fix device ref leaking in acpi_pnp_match
  ACPI: Fix use-after-free in acpi_map_lsapic
  ACPI: processor_driver: add missing kfree
  ACPI, APEI: Fix incorrect APEI register bit width check and usage
  Update documentation for parameter *notrigger* in einj.txt
  ACPI, APEI, EINJ, new parameter to control trigger action
  ACPI, APEI, EINJ, limit the range of einj_param
  ACPI, APEI, Fix ERST header length check
  cpuidle: power_usage should be declared signed integer
  ...
2012-03-30 16:45:39 -07:00
Boris Ostrovsky 02401c06b7 cpuidle: power_usage should be declared signed integer
power_usage is always assigned a negative value and should be declared
a signed integer

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@amd.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2012-03-30 03:23:30 -04:00
Boris Ostrovsky 1a022e3f1b idle, x86: Allow off-lined CPU to enter deeper C states
Currently when a CPU is off-lined it enters either MWAIT-based idle or,
if MWAIT is not desired or supported, HLT-based idle (which places the
processor in C1 state). This patch allows processors without MWAIT
support to stay in states deeper than C1.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@amd.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2012-03-30 03:23:01 -04:00