linux-toradex.git/drivers/cpufreq/pcc-cpufreq.c, branch v3.18.16

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

2014-09-29T13:35:50+00:00

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:[] 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:
 [] dump_stack+0x4d/0x90
 [] ___might_sleep+0x10f/0x180
 [] __might_sleep+0x48/0xd0
 [] cpufreq_freq_transition_begin+0x75/0x140 drivers/cpufreq/cpufreq.c:370 wait_event(policy->transition_wait, !policy->transition_ongoing);
 [] ? preempt_count_add+0xb9/0xc0
 [] pcc_cpufreq_target+0x63/0x200 [pcc_cpufreq] drivers/cpufreq/pcc-cpufreq.c:207 spin_lock(&pcc_lock);
 [] ? update_ts_time_stats+0x7f/0xb0
 [] __cpufreq_driver_target+0x85/0x170
 [] od_check_cpu+0xa8/0xb0
 [] dbs_check_cpu+0x180/0x1d0
 [] cpufreq_governor_dbs+0x3b0/0x720
 [] od_cpufreq_governor_dbs+0x33/0xe0
 [] __cpufreq_governor+0xa9/0x210
 [] cpufreq_set_policy+0x1e2/0x2e0
 [] cpufreq_init_policy+0x8c/0x110
 [] ? cpufreq_update_policy+0x1b0/0x1b0
 [] ? preempt_count_sub+0xb9/0x100
 [] __cpufreq_add_dev+0x596/0x6b0
 [] ? pcc_cpufreq_probe+0x4b4/0x4b4 [pcc_cpufreq]
 [] cpufreq_add_dev+0xe/0x10
 [] subsys_interface_register+0xc1/0xf0
 [] ? preempt_count_sub+0xb9/0x100
 [] cpufreq_register_driver+0x117/0x2a0
 [] pcc_cpufreq_init+0x55/0x9f8 [pcc_cpufreq]
 [] ? pcc_cpufreq_probe+0x4b4/0x4b4 [pcc_cpufreq]
 [] do_one_initcall+0xc8/0x1f0
 [] ? __vunmap+0x9d/0x100
 [] do_init_module+0x30/0x1b0
 [] load_module+0x686/0x710
 [] ? do_init_module+0x1b0/0x1b0
 [] SyS_init_module+0x9b/0xc0
 [] system_call_fastpath+0x16/0x1b

Fixes: 8fec051eea73 (cpufreq: Convert existing drivers to use cpufreq_freq_transition_{begin|end})
Reported-and-tested-by: Mike Galbraith 
Cc: 3.15+  # 3.15+
Signed-off-by: Rafael J. Wysocki

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

2014-03-26T15:41:41+00:00

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 
Signed-off-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki

cpufreq: send new set of notification for transition failures

2014-01-06T00:43:44+00:00

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 
[rjw: Folded 3 patches into one, rebased unicore2 changes]
Signed-off-by: Rafael J. Wysocki

Merge branch 'pm-cpufreq'

2013-10-28T00:29:34+00:00

* 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

2013-10-15T22:50:31+00:00

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 
Signed-off-by: Rafael J. Wysocki

cpufreq: add new routine cpufreq_verify_within_cpu_limits()

2013-10-15T22:50:23+00:00

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 
Acked-by: Dirk Brandewie 
Signed-off-by: Rafael J. Wysocki

pcc_freq: convert acpi_get_handle() to acpi_has_method()

2013-09-23T23:37:55+00:00

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 
Signed-off-by: Rafael J. Wysocki

cpufreq: Drop the owner field from struct cpufreq_driver

2013-08-10T01:24:47+00:00

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 
Signed-off-by: Rafael J. Wysocki

cpufreq: pcc: call CPUFREQ_POSTCHANGE notfier in error cases

2013-06-24T11:26:39+00:00

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 
Signed-off-by: Rafael J. Wysocki

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

2013-04-02T13:24:00+00:00

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 
Acked-by: Stephen Warren 
Tested-by: Stephen Warren 
Signed-off-by: Rafael J. Wysocki