PM: suspend: Fix pm_suspend_target_state handling for !CONFIG_PM

Move the pm_suspend_target_state definition for CONFIG_SUSPEND
unset from the wakeup code into the headers so as to allow it
to still be used elsewhere when CONFIG_SUSPEND is not set.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
[ rjw: Changelog and subject edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: wakeup: Add extra debugging statement for multiple active IRQs

Since commit cb1f65c1e1424 ("PM: s2idle: ACPI: Fix wakeup interrupts
handling") was introduced the kernel can now handle multiple
simultaneous interrupts during wakeup. Ths uncovered some existing
subtle firmware bugs where multiple IRQs are unintentionally active.

To help with fixing those bugs add an extra message when PM debugging
is enabled that can show the individual IRQs triggered as if a variety
are fired they'll potentially be lost as /sys/power/pm_wakeup_irq only
contains the first one that triggered the wakeup after resume is
complete but all may be needed to demonstrate the whole picture.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=215770
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
[ rjw: Added empty line after if () ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: wakeup: Unify device_init_wakeup() for PM_SLEEP and !PM_SLEEP

Previously the CONFIG_PM_SLEEP and !CONFIG_PM_SLEEP device_init_wakeup()
implementations differed in confusing ways:

- The PM_SLEEP version checked for a NULL device pointer and returned
-EINVAL, while the !PM_SLEEP version did not and would simply
dereference a NULL pointer.

- When called with "false", the !PM_SLEEP version cleared "capable" and
"enable" in the opposite order of the PM_SLEEP version. That was
harmless because for !PM_SLEEP they're simple assignments, but it's
unnecessary confusion.

Use a simplified version of the PM_SLEEP implementation for both cases.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: wakeup: expose pm_wakeup_pending to modules

intel_pch_thermal driver needs a long delay to cool itself (60 seconds
in maximum) during suspend. When a wakeup event occures during the
delay, it is better for the intel_pch_thermal driver to detect this and
quit cooling because the suspend is likely to abort anyway.

Thus expose pm_wakeup_pending to modules so that intel_pch_thermal
driver can be aware of the wakeup events.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Tested-by: Sumeet Pawnikar <sumeet.r.pawnikar@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: sleep: wakeup: Fix typos in comments

Remove the second 'the'.
Replace the second 'of' with 'the'.
Replace 'couter' with 'counter'.

Signed-off-by: Tom Rix <trix@redhat.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: s2idle: ACPI: Fix wakeup interrupts handling

After commit e3728b50cd9b ("ACPI: PM: s2idle: Avoid possible race
related to the EC GPE") wakeup interrupts occurring immediately after
the one discarded by acpi_s2idle_wake() may be missed. Moreover, if
the SCI triggers again immediately after the rearming in
acpi_s2idle_wake(), that wakeup may be missed too.

The problem is that pm_system_irq_wakeup() only calls pm_system_wakeup()
when pm_wakeup_irq is 0, but that's not the case any more after the
interrupt causing acpi_s2idle_wake() to run until pm_wakeup_irq is
cleared by the pm_wakeup_clear() call in s2idle_loop(). However,
there may be wakeup interrupts occurring in that time frame and if
that happens, they will be missed.

To address that issue first move the clearing of pm_wakeup_irq to
the point at which it is known that the interrupt causing
acpi_s2idle_wake() to tun will be discarded, before rearming the SCI
for wakeup. Moreover, because that only reduces the size of the
time window in which the issue may manifest itself, allow
pm_system_irq_wakeup() to register two second wakeup interrupts in
a row and, when discarding the first one, replace it with the second
one. [Of course, this assumes that only one wakeup interrupt can be
discarded in one go, but currently that is the case and I am not
aware of any plans to change that.]

Fixes: e3728b50cd9b ("ACPI: PM: s2idle: Avoid possible race related to the EC GPE")
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

driver: base: Replace symbolic permissions with octal permissions

Resolve following checkpatch issue,
Replace symbolic permissions with octal permissions

Signed-off-by: Jinchao Wang <wjc@cdjrlc.com>
Link: https://lore.kernel.org/r/20210626094606.53152-1-wjc@cdjrlc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

PM: wakeup: fix kernel-doc warnings and fix typos

Remove make W=1 warnings and fit 'Itereates' typos

drivers/base/power/wakeup.c:403: warning: wrong kernel-doc identifier on line:
* device_wakeup_arm_wake_irqs(void)

drivers/base/power/wakeup.c:419: warning: wrong kernel-doc identifier on line:
* device_wakeup_disarm_wake_irqs(void)

drivers/base/power/wakeup.c:537: warning: Function parameter or member
'enable' not described in 'device_set_wakeup_enable'

drivers/base/power/wakeup.c:592: warning: expecting prototype for
wakup_source_activate(). Prototype was for wakeup_source_activate()
instead

drivers/base/power/wakeup.c:697: warning: expecting prototype for
wakup_source_deactivate(). Prototype was for
wakeup_source_deactivate() instead

drivers/base/power/wakeup.c:795: warning: Function parameter or member
't' not described in 'pm_wakeup_timer_fn'

drivers/base/power/wakeup.c:795: warning: Excess function parameter
'data' description in 'pm_wakeup_timer_fn'

drivers/base/power/wakeup.c:1027: warning: Function parameter or
member 'set' not described in 'pm_wakep_autosleep_enabled'

drivers/base/power/wakeup.c:1027: warning: Excess function parameter
'enabled' description in 'pm_wakep_autosleep_enabled'

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: sleep: wakeup: Skip wakeup_source_sysfs_remove() if device is not there

Skip wakeup_source_sysfs_remove() to fix a NULL pinter dereference via
ws->dev, if the wakeup source is unregistered before registering the
wakeup class from device_add().

Fixes: 2ca3d1ecb8c4 ("PM / wakeup: Register wakeup class kobj after device is added")
Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+
[ rjw: Subject & changelog, white space ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Revert "drivers: base: power: wakeup.c: Use built-in RCU list checking"

This reverts commit 8ba88804bb3b877c841bc1864a8605111580cd0b as a better
version is already in Rafael's tree, sorry about that.

Reported-by: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers: base: power: wakeup.c: Use built-in RCU list checking

Pass cond argument to list_for_each_entry_rcu() to fix the
following false positive lockdep warning and other uses of
list_for_each_entry_rcu() in wakeup.c.

[ 331.934648] =============================
[ 331.934650] WARNING: suspicious RCU usage
[ 331.934653] 5.6.0-rc1+ #5 Not tainted
[ 331.934655] -----------------------------
[ 331.934657] drivers/base/power/wakeup.c:408 RCU-list traversed in non-reader section!!

[ 333.025156] =============================
[ 333.025161] WARNING: suspicious RCU usage
[ 333.025168] 5.6.0-rc1+ #5 Not tainted
[ 333.025173] -----------------------------
[ 333.025180] drivers/base/power/wakeup.c:424 RCU-list traversed in non-reader section!!

Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Link: https://lore.kernel.org/r/20200228174745.9308-1-madhuparnabhowmik10@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

PM: sleep: wakeup: Use built-in RCU list checking

Pass cond argument to list_for_each_entry_rcu() to fix the
following false positive lockdep warning and other uses of
list_for_each_entry_rcu() in wakeup.c.
(CONFIG_PROVE_RCU_LIST = y)

[ 331.934648] =============================
[ 331.934650] WARNING: suspicious RCU usage
[ 331.934653] 5.6.0-rc1+ #5 Not tainted
[ 331.934655] -----------------------------
[ 331.934657] drivers/base/power/wakeup.c:408 RCU-list traversed in non-reader section!!

[ 333.025156] =============================
[ 333.025161] WARNING: suspicious RCU usage
[ 333.025168] 5.6.0-rc1+ #5 Not tainted
[ 333.025173] -----------------------------
[ 333.025180] drivers/base/power/wakeup.c:424 RCU-list traversed in non-reader section!!

Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: wakeup: Show statistics for deleted wakeup sources again

After commit 00ee22c28915 (PM / wakeup: Use seq_open() to show wakeup
stats), print_wakeup_source_stats(m, &deleted_ws) is not called from
wakeup_sources_stats_seq_show() any more.

Because deleted_ws is one of the wakeup sources, it should be shown
too, so add it to the end of all other wakeup sources.

Signed-off-by: zhuguangqing <zhuguangqing@xiaomi.com>
[ rjw: Subject & changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: wakeup: Add routine to help fetch wakeup source object.

Some user might want to go through all registered wakeup sources
and doing things accordingly. For example, SoC PM driver might need to
do HW programming to prevent powering down specific IP which wakeup
source depending on. So add this API to help walk through all registered
wakeup source objects on that list and return them one by one.

Signed-off-by: Ran Wang <ran.wang_1@nxp.com>
Tested-by: Leonard Crestez <leonard.crestez@nxp.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Li Yang <leoyang.li@nxp.com>

PM / wakeup: Register wakeup class kobj after device is added

The device_set_wakeup_enable() function can be called on a device that
hasn't been registered with device_add() yet. This allows the device to
be in a state where wakeup is enabled for it but the device isn't
published to userspace in sysfs yet.

After commit c8377adfa781 ("PM / wakeup: Show wakeup sources stats in
sysfs"), calling device_set_wakeup_enable() will fail for a device that
hasn't been registered with the driver core via device_add(). This is
because we try to create sysfs entries for the device and associate a
wakeup class kobject with it before the device has been registered.
Let's follow a similar approach that device_set_wakeup_capable() takes
here and register the wakeup class either from
device_set_wakeup_enable() when the device is already registered, or
from dpm_sysfs_add() when the device is being registered with the driver
core via device_add().

Fixes: c8377adfa781 ("PM / wakeup: Show wakeup sources stats in sysfs")
Reported-by: Qian Cai <cai@lca.pw>
Reviewed-by: Tri Vo <trong@android.com>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / wakeup: Fix sysfs registration error path

We shouldn't call wakeup_source_destroy() from the error path in
wakeup_source_register() because that calls __pm_relax() which takes a
lock that isn't initialized until wakeup_source_add() is called. Add a
new function, wakeup_source_free(), that just does the bare minimum to
free a wakeup source that was created but hasn't been added yet and use
it from the two places it's needed. This fixes the following problem
seen on various x86 server boxes:

INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
CPU: 12 PID: 1 Comm: swapper/0 Not tainted 5.3.0-rc4-
Hardware name: HP ProLiant XL420 Gen9/ProLiant XL420 Gen9, BIOS U19 12/27/2015
Call Trace:
  dump_stack+0x62/0x9a
  register_lock_class+0x95a/0x960
  ? __platform_driver_probe+0xcd/0x230
  ? __platform_create_bundle+0xc0/0xe0
  ? i8042_init+0x4ec/0x578
  ? do_one_initcall+0xfe/0x45a
  ? kernel_init_freeable+0x614/0x6a7
  ? kernel_init+0x11/0x138
  ? ret_from_fork+0x35/0x40
  ? is_dynamic_key+0xf0/0xf0
  ? rwlock_bug.part.0+0x60/0x60
  ? __debug_check_no_obj_freed+0x8e/0x250
  __lock_acquire.isra.13+0x5f/0x830
  ? __debug_check_no_obj_freed+0x152/0x250
  lock_acquire+0x107/0x220
  ? __pm_relax.part.2+0x21/0xa0
  _raw_spin_lock_irqsave+0x35/0x50
  ? __pm_relax.part.2+0x21/0xa0
  __pm_relax.part.2+0x21/0xa0
  wakeup_source_destroy.part.3+0x18/0x190
  wakeup_source_register+0x43/0x50

Fixes: c8377adfa781 ("PM / wakeup: Show wakeup sources stats in sysfs")
Reported-by: Qian Cai <cai@lca.pw>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / wakeup: Show wakeup sources stats in sysfs

Add an ID and a device pointer to 'struct wakeup_source'. Use them to to
expose wakeup sources statistics in sysfs under
/sys/class/wakeup/wakeup<ID>/*.

Co-developed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Co-developed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Tri Vo <trong@android.com>
Tested-by: Kalesh Singh <kaleshsingh@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / wakeup: Drop wakeup_source_init(), wakeup_source_prepare()

wakeup_source_init() has no users. Remove it.

As a result, wakeup_source_prepare() is only called from
wakeup_source_create(). Merge wakeup_source_prepare() into
wakeup_source_create() and remove it.

Change wakeup_source_create() behavior so that assigning NULL to wakeup
source's name throws an error.

Signed-off-by: Tri Vo <trong@android.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: sleep: Fix possible overflow in pm_system_cancel_wakeup()

It is not actually guaranteed that pm_abort_suspend will be
nonzero when pm_system_cancel_wakeup() is called which may lead to
subtle issues, so make it use atomic_dec_if_positive() instead of
atomic_dec() for the safety sake.

Fixes: 33e4f80ee69b ("ACPI / PM: Ignore spurious SCI wakeups from suspend-to-idle")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>

drivers: base: power: remove wakeup_sources_stats_dentry variable

wakeup_sources_stats_dentry is assigned when the debugfs file is
created, but then never used ever again. So no need for it at all, just
remove it and call debugfs_create_file() on its own.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers: base: power: add proper SPDX identifiers on files that did not have them.

There were a few files in the driver core power code that did not have
SPDX identifiers on them, so fix that up. At the same time, remove the
"free form" text that specified the license of the file, as that is
impossible for any tool to properly parse.

Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

PM / wakeup: Use pm_pr_dbg() instead of pr_debug()

These prints are useful if we're doing PM suspend debugging. Having them
at pr_debug() level means that we need to either enable DEBUG in this
file, or compile the kernel with dynamic debug capabilities. Both of
these options have drawbacks like custom compilation or opting into all
debug statements being included into the kernel image. Given that we
already have infrastructure to collect PM debugging information with
CONFIG_PM_DEBUG and friends, let's change the pr_debug usage here to be
pm_pr_dbg() instead so we can collect the wakeup information in the
kernel logs.

Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / wakeup: Drop wakeup_source_drop()

After commit d856f39ac1cc ("PM / wakeup: Rework wakeup source timer
cancellation") wakeup_source_drop() is a trivial wrapper around
__pm_relax() and it has no users except for wakeup_source_destroy()
and wakeup_source_trash() which also has no users, so drop it along
with the latter and make wakeup_source_destroy() call __pm_relax()
directly.

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

PM / wakeup: Rework wakeup source timer cancellation

If wakeup_source_add() is called right after wakeup_source_remove()
for the same wakeup source, timer_setup() may be called for a
potentially scheduled timer which is incorrect.

To avoid that, move the wakeup source timer cancellation from
wakeup_source_drop() to wakeup_source_remove().

Moreover, make wakeup_source_remove() clear the timer function after
canceling the timer to let wakeup_source_not_registered() treat
unregistered wakeup sources in the same way as the ones that have
never been registered.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: 4.4+ <stable@vger.kernel.org> # 4.4+
[ rjw: Subject, changelog, merged two patches together ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: Add and use pr_fmt()

Prefix all printk/pr_<level> messages with "PM: " to make the
logging a bit more consistent.

Miscellanea:

o Convert a few printks to pr_<level>
o Whitespace to align to open parentheses
o Remove embedded "PM: " from pr_debugs as pr_fmt adds it

Signed-off-by: Joe Perches <joe@perches.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / wakeup: fix kerneldoc comment for pm_wakeup_dev_event()

This brings the kernel doc in line with the function signature.

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
[ rjw: Subject ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / wakeup: Make events_lock a RAW_SPINLOCK

The `events_lock' is acquired during suspend while interrupts are
disabled even on RT. The lock is taken only for a very brief moment.
Make it a RAW lock which avoids "sleeping while atomic" warnings on RT.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: wakeup: Use pr_debug() for the "aborting suspend" message

The message printed by pm_wakeup_pending() on wakeup detection is
not very useful if someone is not interested specifically in
debugging wakeup, so turn it into a pm_debug() one.

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

PM / wakeup: Only update last time for active wakeup sources

When wakelock support was added, the wakeup_source_add() function
was updated to set the last_time value of the wakeup source. This
has the unintended side effect of producing confusing output from
pm_print_active_wakeup_sources() when a wakeup source is added
prior to a sleep that is blocked by a different wakeup source.

The function pm_print_active_wakeup_sources() will search for the
most recently active wakeup source when no active source is found.
If a wakeup source is added after a different wakeup source blocks
the system from going to sleep it may have a later last_time value
than the blocking source and be output as the last active wakeup
source even if it has never actually been active.

It looks to me like the change to wakeup_source_add() was made to
prevent the wakelock garbage collection from accidentally dropping
a wakelock during the narrow window between adding the wakelock to
the wakelock list in wakelock_lookup_add() and the activation of
the wakeup source in pm_wake_lock().

This commit changes the behavior so that only the last_time of the
wakeup source used by a wakelock is initialized prior to adding it
to the wakeup source list. This preserves the meaning of the
last_time value as the last time the wakeup source was active and
allows a wakeup source that has never been active to have a
last_time value of 0.

Fixes: b86ff9820fd5 (PM / Sleep: Add user space interface for manipulating wakeup sources, v3)
Signed-off-by: Doug Berger <opendmb@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / wakeup: Use seq_open() to show wakeup stats

single_open() interface requires that the whole output must
fit into a single buffer. This will lead to timeout when
system memory is not in a good situation.

This patch use seq_open() to show wakeup stats. This method
need only one page, so timeout will not be observed.

Signed-off-by: Ganesh Mahendran <opensource.ganesh@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / wakeup: Print warn if device gets enabled as wakeup source during sleep

In general, wakeup settings are not supposed to be changed during any of
the system wide PM phases. The reason is simply that it would break
guarantees provided by the PM core, to properly act on active wakeup
sources.

However, there are exceptions to when, in particular, disabling a device as
wakeup source makes sense. For example, in cases when a driver realizes
that its device is dead during system suspend. For these scenarios, we
don't need to care about acting on the wakeup source correctly, because a
dead device shouldn't deliver wakeup signals.

To this reasoning and to help users to properly manage wakeup settings,
let's print a warning in cases someone calls device_wakeup_enable() during
system sleep.

Suggested-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
[ rjw: Message to be printed ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / wakeup: Do not fail dev_pm_attach_wake_irq() unnecessarily

Returning an error code from dev_pm_attach_wake_irq() if
device_wakeup_attach_irq() called by it returns an error is
pointless, because the wakeup source used by it may be deleted
by user space via sysfs at any time and in particular right after
dev_pm_attach_wake_irq() has returned. Moreover, it requires
the callers of dev_pm_attach_wake_irq() to create that wakeup
source via device_wakeup_enable() upfront, but that obviously is
racy with respect to the sysfs-based manipulations of it.

To avoid the race, modify device_wakeup_attach_irq() to check
that the wakeup source it is going to use is there (and return
early otherwise), make it void (as it cannot fail after that
change) and make dev_pm_attach_wake_irq() simply call it for
the device unconditionally.

Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / wakeup: Drop redundant check from device_init_wakeup()

Since device_wakeup_disable() checks the device's power.can_wakeup
flag, device_init_wakeup() doesn't need to do that before calling it,
so drop that redundant check from device_init_wakeup().

No intentional changes in functionality.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

PM / wakeup: Drop redundant check from device_set_wakeup_enable()

Since both device_wakeup_enable() and device_wakeup_disable() check
if dev is not NULL and whether or not power.can_wakeup is set for it,
device_set_wakeup_enable() doesn't have to do that, so drop that
check from it.

No intentional changes in functionality.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

PM / wakeup: only recommend "call"ing device_init_wakeup() once

I'll admit admit it: I've written bad driver code that tries to
configure a device's wake IRQ without having called device_init_wakeup()
first. But do you really have to ask ask me twice?

Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

treewide: Remove TIMER_FUNC_TYPE and TIMER_DATA_TYPE casts

With all callbacks converted, and the timer callback prototype
switched over, the TIMER_FUNC_TYPE cast is no longer needed,
so remove it. Conversion was done with the following scripts:

perl -pi -e 's|\(TIMER_FUNC_TYPE\)||g' \
$(git grep TIMER_FUNC_TYPE | cut -d: -f1 | sort -u)

perl -pi -e 's|\(TIMER_DATA_TYPE\)||g' \
$(git grep TIMER_DATA_TYPE | cut -d: -f1 | sort -u)

The now unused macros are also dropped from include/linux/timer.h.

Signed-off-by: Kees Cook <keescook@chromium.org>

PM / core: Convert timers to use timer_setup()

In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly. Removes test of .data field, since
that will be going away.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / s2idle: Rename freeze_state enum and related items

Rename the freeze_state enum representing the suspend-to-idle state
machine states to s2idle_states and rename the related variables and
functions accordingly.

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

PM / wakeup: Set power.can_wakeup if wakeup_sysfs_add() fails

Currently, an error from wakeup_sysfs_add() in
device_set_wakeup_capable() causes the device's power.can_wakeup
flag to remain unset even though the device technically is capable
of signaling wakeup.

If wakeup_sysfs_add() fails user space may not be able to enable
the device to wake up the system from sleep states, but at least
for some devices that does not matter.

For this reason, set or clear power.can_wakeup upfront and if
wakeup_sysfs_add() returns an error, print a message to the log.

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

PM / wakeirq: Convert to SRCU

The wakeirq infrastructure uses RCU to protect the list of wakeirqs. That
breaks the irq bus locking infrastructure, which is allows sleeping
functions to be called so interrupt controllers behind slow busses,
e.g. i2c, can be handled.

The wakeirq functions hold rcu_read_lock and call into irq functions, which
in case of interrupts using the irq bus locking will trigger a
might_sleep() splat.

Convert the wakeirq infrastructure to Sleepable RCU and unbreak it.

Fixes: 4990d4fe327b (PM / Wakeirq: Add automated device wake IRQ handling)
Reported-by: Brian Norris <briannorris@chromium.org>
Suggested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Brian Norris <briannorris@chromium.org>
Cc: 4.2+ <stable@vger.kernel.org> # 4.2+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI / PM: Ignore spurious SCI wakeups from suspend-to-idle

The ACPI SCI (System Control Interrupt) is set up as a wakeup IRQ
during suspend-to-idle transitions and, consequently, any events
signaled through it wake up the system from that state. However,
on some systems some of the events signaled via the ACPI SCI while
suspended to idle should not cause the system to wake up. In fact,
quite often they should just be discarded.

Arguably, systems should not resume entirely on such events, but in
order to decide which events really should cause the system to resume
and which are spurious, it is necessary to resume up to the point
when ACPI SCIs are actually handled and processed, which is after
executing dpm_resume_noirq() in the system resume path.

For this reasons, add a loop around freeze_enter() in which the
platforms can process events signaled via multiplexed IRQ lines
like the ACPI SCI and add suspend-to-idle hooks that can be
used for this purpose to struct platform_freeze_ops.

In the ACPI case, the ->wake hook is used for checking if the SCI
has triggered while suspended and deferring the interrupt-induced
system wakeup until the events signaled through it are actually
processed sufficiently to decide whether or not the system should
resume. In turn, the ->sync hook allows all of the relevant event
queues to be flushed so as to prevent events from being missed due
to race conditions.

In addition to that, some ACPI code processing wakeup events needs
to be modified to use the "hard" version of wakeup triggers, so that
it will cause a system resume to happen on device-induced wakeup
events even if the "soft" mechanism to prevent the system from
suspending is not enabled. However, to preserve the existing
behavior with respect to suspend-to-RAM, this only is done in
the suspend-to-idle case and only if an SCI has occurred while
suspended.

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

Revert "ACPI / sleep: Ignore spurious SCI wakeups from suspend-to-idle"

Revert commit eed4d47efe95 (ACPI / sleep: Ignore spurious SCI wakeups
from suspend-to-idle) as it turned out to be premature and triggered
a number of different issues on various systems.

That includes, but is not limited to, premature suspend-to-RAM aborts
on Dell XPS 13 (9343) reported by Dominik.

The issue the commit in question attempted to address is real and
will need to be taken care of going forward, but evidently more work
is needed for this purpose.

Reported-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / wakeup: Fix up wakeup_source_report_event()

Commit 8a537ece3d94 (PM / wakeup: Integrate mechanism to abort
transitions in progress) modified wakeup_source_report_event()
and wakeup_source_activate() to make it possible to call
pm_system_wakeup() from the latter if so indicated by the
caller of the former (via a new function argument added by that
commit), but it overlooked the fact that in some situations
wakeup_source_report_event() is called to signal a "hard" event
(ie. such that should abort a system suspend in progress) after
pm_stay_awake() has been called for the same wakeup source object,
in which case the pm_system_wakeup() will not trigger.

To work around this issue, modify wakeup_source_activate() and
wakeup_source_report_event() again so that pm_system_wakeup() is
called by the latter directly (if its last argument is true), in
which case the additional argument does not need to be passed
to wakeup_source_activate() any more, so drop it from there.

Fixes: 8a537ece3d94 (PM / wakeup: Integrate mechanism to abort transitions in progress)
Reported-by: David E. Box <david.e.box@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI / sleep: Ignore spurious SCI wakeups from suspend-to-idle

The ACPI SCI (System Control Interrupt) is set up as a wakeup IRQ
during suspend-to-idle transitions and, consequently, any events
signaled through it wake up the system from that state. However,
on some systems some of the events signaled via the ACPI SCI while
suspended to idle should not cause the system to wake up. In fact,
quite often they should just be discarded.

Arguably, systems should not resume entirely on such events, but in
order to decide which events really should cause the system to resume
and which are spurious, it is necessary to resume up to the point
when ACPI SCIs are actually handled and processed, which is after
executing dpm_resume_noirq() in the system resume path.

For this reasons, add a loop around freeze_enter() in which the
platforms can process events signaled via multiplexed IRQ lines
like the ACPI SCI and add suspend-to-idle hooks that can be
used for this purpose to struct platform_freeze_ops.

In the ACPI case, the ->wake hook is used for checking if the SCI
has triggered while suspended and deferring the interrupt-induced
system wakeup until the events signaled through it are actually
processed sufficiently to decide whether or not the system should
resume. In turn, the ->sync hook allows all of the relevant event
queues to be flushed so as to prevent events from being missed due
to race conditions.

In addition to that, some ACPI code processing wakeup events needs
to be modified to use the "hard" version of wakeup triggers, so that
it will cause a system resume to happen on device-induced wakeup
events even if the "soft" mechanism to prevent the system from
suspending is not enabled (that also helps to catch device-induced
wakeup events occurring during suspend transitions in progress).

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

PM / wakeup: Integrate mechanism to abort transitions in progress

The system wakeup framework is not very consistent with respect to
the way it handles suspend-to-idle and generally wakeup events
occurring during transitions to system low-power states.

First off, system transitions in progress are aborted by the event
reporting helpers like pm_wakeup_event() only if the wakeup_count
sysfs attribute is in use (as documented), but there are cases in
which system-wide transitions should be aborted even if that is
not the case. For example, a wakeup signal from a designated
wakeup device during system-wide PM transition, it should cause
the transition to be aborted right away.

Moreover, there is a freeze_wake() call in wakeup_source_activate(),
but that really is only effective after suspend_freeze_state has
been set to FREEZE_STATE_ENTER by freeze_enter(). However, it
is very unlikely that wakeup_source_activate() will ever be called
at that time, as it could only be triggered by a IRQF_NO_SUSPEND
interrupt handler, so wakeups from suspend-to-idle don't really
occur in wakeup_source_activate().

At the same time there is a way to abort a system suspend in
progress (or wake up the system from suspend-to-idle), which is by
calling pm_system_wakeup(), but in turn that doesn't cause any
wakeup source objects to be activated, so it will not be covered
by wakeup source statistics and will not prevent the system from
suspending again immediately (in case autosleep is used, for
example). Consequently, if anyone wants to abort system transitions
in progress and allow the wakeup_count mechanism to work, they need
to use both pm_system_wakeup() and pm_wakeup_event(), say, at the
same time which is awkward.

For the above reasons, make it possible to trigger
pm_system_wakeup() from within wakeup_source_activate() and
provide a new pm_wakeup_hard_event() helper to do so within the
wakeup framework.

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

sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h>

Fix up affected files that include this signal functionality via sched.h.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

ktime: Cleanup ktime_set() usage

ktime_set(S,N) was required for the timespec storage type and is still
useful for situations where a Seconds and Nanoseconds part of a time value
needs to be converted. For anything where the Seconds argument is 0, this
is pointless and can be replaced with a simple assignment.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>

ktime: Get rid of the union

ktime is a union because the initial implementation stored the time in
scalar nanoseconds on 64 bit machine and in a endianess optimized timespec
variant for 32bit machines. The Y2038 cleanup removed the timespec variant
and switched everything to scalar nanoseconds. The union remained, but
become completely pointless.

Get rid of the union and just keep ktime_t as simple typedef of type s64.

The conversion was done with coccinelle and some manual mopping up.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>

PM / sleep: Print active wakeup sources when blocking on wakeup_count reads

If there are any wakeup events being processed, read operation
on /sys/power/wakeup_count will be blocked, so print the names
of all active wakeup sources to help to find out who is preventing
system suspend from triggering.

While at it change pr_info() in pm_print_active_wakeup_sources()
to pr_debug() to avoid excessive log noise.

Signed-off-by: xing wei <xing.wei@intel.com>
[ rjw: Subject & changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM-wakeup: Delete unnecessary checks before three function calls

The following functions test whether their argument is NULL
and then return immediately.
* dev_pm_arm_wake_irq
* dev_pm_disarm_wake_irq
* wakeup_source_unregister

Thus the test around the calls is not needed.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Acked-by: Pavel Machek <pavel@ucw.cz>
[ rjw: Minor whitespace adjustments ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / wakeirq: fix wakeirq setting after wakup re-configuration from sysfs

Now wakeirq stops working for device if wakeup option for
this device will be reconfigured through sysfs, like:

echo disabled > /sys/devices/platform/extcon_usb1/power/wakeup
echo enabled > /sys/devices/platform/extcon_usb1/power/wakeup

Once above set of commands is executed the device's wakeup_source
opject will be recreated and dev->power.wakeup->wakeirq field will
contain NULL. As result, device_wakeup_arm_wake_irqs() will not arm
wakeirq for the affected device.

Hece, lets try to fix it in the following way:
check for dev->wakeirq field when device_wakeup_attach() is called
and if !NULL re-attach wakeirq to the device

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / wakeup: wakeup_source_create: use kstrdup_const

Using kstrdup_const allows us to save a little runtime memory (and a
string copy) in the common case where name is a string literal.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / sleep: Report interrupt that caused system wakeup

Add a sysfs attribute, /sys/power/pm_wakeup_irq, reporting the IRQ
number of the first wakeup interrupt (that is, the first interrupt
from an IRQ line armed for system wakeup) seen by the kernel during
the most recent system suspend/resume cycle.

This feature will be useful for system wakeup diagnostics of
spurious wakeup interrupts.

Signed-off-by: Alexandra Yates <alexandra.yates@linux.intel.com>
[ rjw: Fixed up pm_wakeup_irq definition ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / wakeirq: Avoid setting power.wakeirq too hastily

If dev_pm_attach_wake_irq() fails, the device's power.wakeirq field
should not be set to point to the struct wake_irq passed to that
function, as that object will be freed going forward.

For this reason, make dev_pm_attach_wake_irq() first call
device_wakeup_attach_irq() and only set the device's power.wakeirq
field if that's successful.

That requires device_wakeup_attach_irq() to be called under the
device's power.lock lock, but since dev_pm_attach_wake_irq() is
the only caller of it, the requisite changes are easy to make.

Fixes: 4990d4fe327b (PM / Wakeirq: Add automated device wake IRQ handling)
Reported-by: Felipe Balbi <balbi@ti.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / Wakeirq: Add automated device wake IRQ handling

Turns out we can automate the handling for the device_may_wakeup()
quite a bit by using the kernel wakeup source list as suggested
by Rafael J. Wysocki <rjw@rjwysocki.net>.

And as some hardware has separate dedicated wake-up interrupt
in addition to the IO interrupt, we can automate the handling by
adding a generic threaded interrupt handler that just calls the
device PM runtime to wake up the device.

This allows dropping code from device drivers as we currently
are doing it in multiple ways, and often wrong.

For most drivers, we should be able to drop the following
boilerplate code from runtime_suspend and runtime_resume
functions:

...
device_init_wakeup(dev, true);
...
if (device_may_wakeup(dev))
enable_irq_wake(irq);
...
if (device_may_wakeup(dev))
disable_irq_wake(irq);
...
device_init_wakeup(dev, false);
...

We can replace it with just the following init and exit
time code:

...
device_init_wakeup(dev, true);
dev_pm_set_wake_irq(dev, irq);
...
dev_pm_clear_wake_irq(dev);
device_init_wakeup(dev, false);
...

And for hardware with dedicated wake-up interrupts:

...
device_init_wakeup(dev, true);
dev_pm_set_dedicated_wake_irq(dev, irq);
...
dev_pm_clear_wake_irq(dev);
device_init_wakeup(dev, false);
...

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / wakeup: add a dummy wakeup_source to record statistics

After a wakeup_source is destroyed, we lost all information such as how
long this wakeup_source has been active. Add a dummy wakeup_source to
record such info.

Signed-off-by: Jin Qian <jinqian@android.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / wakeup: validate wakeup source before activating it.

A rogue wakeup source not registered in wakeup_sources list is not visible
from wakeup_sources_stats_show. Check if the wakeup source is registered
properly by looking at the timer struct.

Signed-off-by: Jin Qian <jinqian@android.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

power: wakeup: remove use of seq_printf return value

The seq_printf return value, because it's frequently misused,
will eventually be converted to void.

See: commit 1f33c41c03da ("seq_file: Rename seq_overflow() to
seq_has_overflowed() and make public")

Signed-off-by: Joe Perches <joe@perches.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Len Brown <len.brown@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

PM / wakeup: export pm_system_wakeup symbol

Export pm_system_wakeup function to allow irq handlers to deal with system
wakeup.

This is needed for shared IRQ lines where one of the handler is registered
with IRQF_NO_SUSPEND, while the other ones want to configure it as a wakeup
source.

In this specific case, irq core does not handle the wakeup process and
leave the decision to each irq handler.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Reviewed-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / sleep: Mechanism for aborting system suspends unconditionally

It sometimes may be necessary to abort a system suspend in
progress or wake up the system from suspend-to-idle even if the
pm_wakeup_event()/pm_stay_awake() mechanism is not enabled.

For this purpose, introduce a new global variable pm_abort_suspend
and make pm_wakeup_pending() check its value. Also add routines
for manipulating that variable.

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

PM / sleep: unregister wakeup source when disabling device wakeup

When enabling a device' wakeup capability, a wakeup source
is created for the device automatically. But the wakeup source
is not unregistered when disabling the device' wakeup capability.

This results in zombie wakeup sources, after devices/drivers are unregistered.

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

PM / Sleep: Print last wakeup source on failed wakeup_count write

Commit a938da06 introduced a useful little log message to tell
users/debuggers which wakeup source aborted a suspend. However,
this message is only printed if the abort happens during the
in-kernel suspend path (after writing /sys/power/state).

The full specification of the /sys/power/wakeup_count facility
allows user-space power managers to double-check if wakeups have
already happened before it actually tries to suspend (e.g. while it
was running user-space pre-suspend hooks), by writing the last known
wakeup_count value to /sys/power/wakeup_count. This patch changes
the sysfs handler for that node to also print said log message if
that write fails, so that we can figure out the offending wakeup
source for both kinds of suspend aborts.

Signed-off-by: Julius Werner <jwerner@chromium.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / wakeup: Adjust messaging for wake events during suspend

This adds in a new message to the wakeup code which adds an
indication to the log that suspend was cancelled due to a wake event
occouring during the suspend sequence. It also adjusts the message
printed in suspend.c to reflect the potential that a suspend was
aborted, as opposed to a device failing to suspend.

Without these message adjustments one can end up with a kernel log
that says that a device failed to suspend with no actual device
suspend failures, which can be confusing to the log examiner.

Signed-off-by: Bernie Thompson <bhthompson@chromium.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: Introduce suspend state PM_SUSPEND_FREEZE

PM_SUSPEND_FREEZE state is a general state that
does not need any platform specific support, it equals
frozen processes + suspended devices + idle processors.

Compared with PM_SUSPEND_MEMORY,
PM_SUSPEND_FREEZE saves less power
because the system is still in a running state.
PM_SUSPEND_FREEZE has less resume latency because it does not
touch BIOS, and the processors are in idle state.

Compared with RTPM/idle,
PM_SUSPEND_FREEZE saves more power as
1. the processor has longer sleep time because processes are frozen.
The deeper c-state the processor supports, more power saving we can get.
2. PM_SUSPEND_FREEZE uses system suspend code path, thus we can get
more power saving from the devices that does not have good RTPM support.

This state is useful for
1) platforms that do not have STR, or have a broken STR.
2) platforms that have an extremely low power idle state,
which can be used to replace STR.

The following describes how PM_SUSPEND_FREEZE state works.
1. echo freeze > /sys/power/state
2. the processes are frozen.
3. all the devices are suspended.
4. all the processors are blocked by a wait queue
5. all the processors idles and enters (Deep) c-state.
6. an interrupt fires.
7. a processor is woken up and handles the irq.
8. if it is a general event,
a) the irq handler runs and quites.
b) goto step 4.
9. if it is a real wake event, say, power button pressing, keyboard touch, mouse moving,
a) the irq handler runs and activate the wakeup source
b) wakeup_source_activate() notifies the wait queue.
c) system starts resuming from PM_SUSPEND_FREEZE
10. all the devices are resumed.
11. all the processes are unfrozen.
12. system is back to working.

Known Issue:
The wakeup of this new PM_SUSPEND_FREEZE state may behave differently
from the previous suspend state.
Take ACPI platform for example, there are some GPEs that only enabled
when the system is in sleep state, to wake the system backk from S3/S4.
But we are not touching these GPEs during transition to PM_SUSPEND_FREEZE.
This means we may lose some wake event.
But on the other hand, as we do not disable all the Interrupts during
PM_SUSPEND_FREEZE, we may get some extra "wakeup" Interrupts, that are
not available for S3/S4.

The patches has been tested on an old Sony laptop, and here are the results:

Average Power:
1. RPTM/idle for half an hour:
14.8W, 12.6W, 14.1W, 12.5W, 14.4W, 13.2W, 12.9W
2. Freeze for half an hour:
11W, 10.4W, 9.4W, 11.3W 10.5W
3. RTPM/idle for three hours:
11.6W
4. Freeze for three hours:
10W
5. Suspend to Memory:
0.5~0.9W

Average Resume Latency:
1. RTPM/idle with a black screen: (From pressing keyboard to screen back)
Less than 0.2s
2. Freeze: (From pressing power button to screen back)
2.50s
3. Suspend to Memory: (From pressing power button to screen back)
4.33s

>From the results, we can see that all the platforms should benefit from
this patch, even if it does not have Low Power S0.

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

PM / wakeup: Use irqsave/irqrestore for events_lock

Jon Medhurst (Tixy) recently noticed a problem with the
events_lock usage. One of the Android patches that uses
wakeup_sources calls wakeup_source_add() with irqs disabled.
However, the event_lock usage in wakeup_source_add() uses
spin_lock_irq()/spin_unlock_irq(), which reenables interrupts.
This results in lockdep warnings.

The fix is to use spin_lock_irqsave()/spin_lock_irqrestore()
instead for the events_lock.

References: https://bugs.launchpad.net/linaro-landing-team-arm/+bug/1037565
Reported-and-debugged-by: Jon Medhurst (Tixy) <tixy@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / Sleep: Print name of wakeup source that aborts suspend

A driver or app may repeatedly request a wakeup source while the system
is attempting to enter suspend, which may indicate a bug or at least
point out a highly active system component that is responsible for
decreased battery life on a mobile device. Even when the incidence
of suspend abort is not severe, identifying wakeup sources that
frequently abort suspend can be a useful clue for power management
analysis.

In some cases the existing stats can point out the offender where there is
an unexpectedly high activation count that stands out from the others, but
in other cases the wakeup source frequently taken just after the rest of
the system thinks its time to suspend might not stand out in the overall
stats.

It is also often useful to have information about what's been happening
recently, rather than totals of all activity for the system boot.

It's suggested to dump a line about which wakeup source
aborted suspend to aid analysis of these situations.

Signed-off-by: Todd Poynor <toddpoynor@google.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / Sleep: Add user space interface for manipulating wakeup sources, v3

Android allows user space to manipulate wakelocks using two
sysfs file located in /sys/power/, wake_lock and wake_unlock.
Writing a wakelock name and optionally a timeout to the wake_lock
file causes the wakelock whose name was written to be acquired (it
is created before is necessary), optionally with the given timeout.
Writing the name of a wakelock to wake_unlock causes that wakelock
to be released.

Implement an analogous interface for user space using wakeup sources.
Add the /sys/power/wake_lock and /sys/power/wake_unlock files
allowing user space to create, activate and deactivate wakeup
sources, such that writing a name and optionally a timeout to
wake_lock causes the wakeup source of that name to be activated,
optionally with the given timeout. If that wakeup source doesn't
exist, it will be created and then activated. Writing a name to
wake_unlock causes the wakeup source of that name, if there is one,
to be deactivated. Wakeup sources created with the help of
wake_lock that haven't been used for more than 5 minutes are garbage
collected and destroyed. Moreover, there can be only WL_NUMBER_LIMIT
wakeup sources created with the help of wake_lock present at a time.

The data type used to track wakeup sources created by user space is
called "struct wakelock" to indicate the origins of this feature.

This version of the patch includes an rbtree manipulation fix from John Stultz.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NeilBrown <neilb@suse.de>

PM / Sleep: Add "prevent autosleep time" statistics to wakeup sources

Android uses one wakelock statistics that is only necessary for
opportunistic sleep. Namely, the prevent_suspend_time field
accumulates the total time the given wakelock has been locked
while "automatic suspend" was enabled. Add an analogous field,
prevent_sleep_time, to wakeup sources and make it behave in a similar
way.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

PM / Sleep: Implement opportunistic sleep, v2

Introduce a mechanism by which the kernel can trigger global
transitions to a sleep state chosen by user space if there are no
active wakeup sources.

It consists of a new sysfs attribute, /sys/power/autosleep, that
can be written one of the strings returned by reads from
/sys/power/state, an ordered workqueue and a work item carrying out
the "suspend" operations. If a string representing the system's
sleep state is written to /sys/power/autosleep, the work item
triggering transitions to that state is queued up and it requeues
itself after every execution until user space writes "off" to
/sys/power/autosleep.

That work item enables the detection of wakeup events using the
functions already defined in drivers/base/power/wakeup.c (with one
small modification) and calls either pm_suspend(), or hibernate() to
put the system into a sleep state. If a wakeup event is reported
while the transition is in progress, it will abort the transition and
the "system suspend" work item will be queued up again.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NeilBrown <neilb@suse.de>

PM / Sleep: Add wakeup_source_activate and wakeup_source_deactivate tracepoints

Add tracepoints to wakeup_source_activate and wakeup_source_deactivate.
Useful for checking that specific wakeup sources overlap as expected.

Signed-off-by: Arve Hjønnevåg <arve@android.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / Sleep: Change wakeup source statistics to follow Android

Wakeup statistics used by Android are slightly different from what we
have in wakeup sources at the moment and there aren't any known
users of those statistics other than Android, so modify them to make
it easier for Android to switch to wakeup sources.

This removes the struct wakeup_source's hit_cout field, which is very
rough and therefore not very useful, and adds two new fields,
wakeup_count and expire_count. The first one tracks how many times
the wakeup source is activated with events_check_enabled set (which
roughly corresponds to the situations when a system power transition
to a sleep state is in progress and would be aborted by this wakeup
source if it were the only active one at that time) and the second
one is the number of times the wakeup source has been activated with
a timeout that expired.

Additionally, the last_time field is now updated when the wakeup
source is deactivated too (previously it was only updated during
the wakeup source's activation), which seems to be what Android does
with the analogous counter for wakelocks.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

PM / Sleep: Use wait queue to signal "no wakeup events in progress"

The current wakeup source deactivation code doesn't do anything when
the counter of wakeup events in progress goes down to zero, which
requires pm_get_wakeup_count() to poll that counter periodically.
Although this reduces the average time it takes to deactivate a
wakeup source, it also may lead to a substantial amount of unnecessary
polling if there are extended periods of wakeup activity. Thus it
seems reasonable to use a wait queue for signaling the "no wakeup
events in progress" condition and remove the polling.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: mark gross <markgross@thegnar.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

PM / Sleep: Add more wakeup source initialization routines

The existing wakeup source initialization routines are not
particularly useful for wakeup sources that aren't created by
wakeup_source_create(), because their users have to open code
filling the objects with zeros and setting their names. For this
reason, introduce routines that can be used for initializing, for
example, static wakeup source objects.

Requested-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / Sleep: Make __pm_stay_awake() delete wakeup source timers

If __pm_stay_awake() is called after __pm_wakeup_event() for the same
wakep source object before its timer expires, it won't cancel the
timer, so the wakeup source will be deactivated from the timer
function as scheduled by __pm_wakeup_event(). In that case
__pm_stay_awake() doesn't have any effect beyond incrementing
the wakeup source's event_count field, although it should cancel
the timer and make the wakeup source stay active until __pm_relax()
is called for it.

To fix this problem make __pm_stay_awake() delete the wakeup source's
timer and ensure that it won't be deactivated from the timer funtion
afterwards by clearing its timer_expires field.

Reported-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / Sleep: Fix race conditions related to wakeup source timer function

If __pm_wakeup_event() has been used (with a nonzero timeout) to
report a wakeup event and then __pm_relax() immediately followed by
__pm_stay_awake() is called or __pm_wakeup_event() is called once
again for the same wakeup source object before its timer expires, the
timer function pm_wakeup_timer_fn() may still be run as a result of
the previous __pm_wakeup_event() call. In either of those cases it
may mistakenly deactivate the wakeup source that has just been
activated.

To prevent that from happening, make wakeup_source_deactivate()
clear the wakeup source's timer_expires field and make
pm_wakeup_timer_fn() check if timer_expires is different from zero
and if it's not in future before calling wakeup_source_deactivate()
(if timer_expires is 0, it means that the timer has just been
deleted and if timer_expires is in future, it means that the timer
has just been rescheduled to a different time).

Reported-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / Sleep: Fix possible infinite loop during wakeup source destruction

If wakeup_source_destroy() is called for an active wakeup source that
is never deactivated, it will spin forever. To prevent that from
happening, make wakeup_source_destroy() call __pm_relax() for the
wakeup source object it is about to free instead of waiting until
it will be deactivated by someone else. However, for this to work
it also needs to make sure that the timer function will not be
executed after the final __pm_relax(), so make it run
del_timer_sync() on the wakeup source's timer beforehand.

Additionally, update the kerneldoc comment to document the
requirement that __pm_stay_awake() and __pm_wakeup_event() must not
be run in parallel with wakeup_source_destroy().

Reported-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / Sleep: Initialize wakeup source locks in wakeup_source_add()

Initialize wakeup source locks in wakeup_source_add() instead of
wakeup_source_create(), because otherwise the locks of the wakeup
sources that haven't been allocated with wakeup_source_create()
aren't initialized and handled properly.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

drivers/base: Add export.h for EXPORT_SYMBOL/THIS_MODULE as required.

Most of these files were implicitly getting EXPORT_SYMBOL via
device.h which was including module.h, but that path will be broken
soon.

[ with input from Stephen Rothwell <sfr@canb.auug.org.au> ]

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

PM: Update the policy on default wakeup settings

This patch (as1485) documents a change to the kernel's default wakeup
policy. Devices that forward wakeup requests between buses should be
enabled for wakeup by default.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / Wakeup: Remove useless synchronize_rcu() call

wakeup_source_add() adds an item into wakeup_sources list.

There is no need to call synchronize_rcu() at this point.

Its only needed in wakeup_source_remove()

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / Wakeup: Fix initialization of wakeup-related device sysfs files

It turns out that some PCI devices are only found to be
wakeup-capable during registration, in which case, when
device_set_wakeup_capable() is called, device_is_registered() already
returns 'true' for the given device, but dpm_sysfs_add() hasn't been
called for it yet. This leads to situations in which the device's
power.can_wakeup flag is not set as requested because of failing
wakeup_sysfs_add() and its wakeup-related sysfs files are not
created, although they should be present. This is a post-2.6.38
regression introduced by commit cb8f51bdadb7969139c2e39c2defd4cde98c1
(PM: Do not create wakeup sysfs files for devices that cannot wake
up).

To work around this problem initialize the device's power.entry
field to an empty list head and make device_set_wakeup_capable()
check if it is still empty before attempting to add the devices
wakeup-related sysfs files with wakeup_sysfs_add(). Namely, if
power.entry is still empty at this point, device_pm_add() hasn't been
called yet for the device and its wakeup-related files will be
created later, so device_set_wakeup_capable() doesn't have to create
them.

Reported-and-tested-by: Tino Keitel <tino.keitel@tikei.de>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>

PM: Do not create wakeup sysfs files for devices that cannot wake up

Currently, wakeup sysfs attributes are created for all devices,
regardless of whether or not they are wakeup-capable. This is
excessive and complicates wakeup device identification from user
space (i.e. to identify wakeup-capable devices user space has to read
/sys/devices/.../power/wakeup for all devices and see if they are not
empty).

Fix this issue by avoiding to create wakeup sysfs files for devices
that cannot wake up the system from sleep states (i.e. whose
power.can_wakeup flags are unset during registration) and modify
device_set_wakeup_capable() so that it adds (or removes) the relevant
sysfs attributes if a device's wakeup capability status is changed.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / Wakeup: Don't update events_check_enabled in pm_get_wakeup_count()

Since pm_save_wakeup_count() has just been changed to clear
events_check_enabled unconditionally before checking if there are
any new wakeup events registered since the last read from
/sys/power/wakeup_count, the detection of wakeup events during
suspend may be disabled, after it's been enabled, by writing a
"wrong" value back to /sys/power/wakeup_count. For this reason,
it is not necessary to update events_check_enabled in
pm_get_wakeup_count() any more.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / Wakeup: Make pm_save_wakeup_count() work as documented

According to Documentation/ABI/testing/sysfs-power, the
/sys/power/wakeup_count interface should only make the kernel react
to wakeup events during suspend if the last write to it has been
successful. However, if /sys/power/wakeup_count is written to two
times in a row, where the first write is successful and the second
is not, the kernel will still react to wakeup events during suspend
due to a bug in pm_save_wakeup_count().

Fix the bug by making pm_save_wakeup_count() clear
events_check_enabled unconditionally before checking if there are
any new wakeup events registered since the previous read from
/sys/power/wakeup_count.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / Wakeup: Combine atomic counters to avoid reordering issues

The memory barrier in wakeup_source_deactivate() is supposed to
prevent the callers of pm_wakeup_pending() and pm_get_wakeup_count()
from seeing the new value of events_in_progress (0, in particular)
and the old value of event_count at the same time. However, if
wakeup_source_deactivate() is executed by CPU0 and, for instance,
pm_wakeup_pending() is executed by CPU1, where both processors can
reorder operations, the memory barrier in wakeup_source_deactivate()
doesn't affect CPU1 which can reorder reads. In that case CPU1 may
very well decide to fetch event_count before it's modified and
events_in_progress after it's been updated, so pm_wakeup_pending()
may fail to detect a wakeup event. This issue can be addressed by
using a single atomic variable to store both events_in_progress
and event_count, so that they can be updated together in a single
atomic operation.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / Wakeup: Replace pm_check_wakeup_events() with pm_wakeup_pending()

To avoid confusion with the meaning and return value of
pm_check_wakeup_events() replace it with pm_wakeup_pending() that
will work the other way around (ie. return true when system-wide
power transition should be aborted).

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / Wakeup: Show wakeup sources statistics in debugfs

There may be wakeup sources that aren't associated with any devices
and their statistics information won't be available from sysfs. Also,
for debugging purposes it is convenient to have all of the wakeup
sources statistics available from one place. For these reasons,
introduce new file "wakeup_sources" in debugfs containing those
statistics.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>

PM / Wakeup: Introduce wakeup source objects and event statistics (v3)

Introduce struct wakeup_source for representing system wakeup sources
within the kernel and for collecting statistics related to them.
Make the recently introduced helper functions pm_wakeup_event(),
pm_stay_awake() and pm_relax() use struct wakeup_source objects
internally, so that wakeup statistics associated with wakeup devices
can be collected and reported in a consistent way (the definition of
pm_relax() is changed, which is harmless, because this function is
not called directly by anyone yet). Introduce new wakeup-related
sysfs device attributes in /sys/devices/.../power for reporting the
device wakeup statistics.

Change the global wakeup events counters event_count and
events_in_progress into atomic variables, so that it is not necessary
to acquire a global spinlock in pm_wakeup_event(), pm_stay_awake()
and pm_relax(), which should allow us to avoid lock contention in
these functions on SMP systems with many wakeup devices.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>

PM: Do not use dynamically allocated objects in pm_wakeup_event()

Originally, pm_wakeup_event() uses struct delayed_work objects,
allocated with GFP_ATOMIC, to schedule the execution of pm_relax()
in future. However, as noted by Alan Stern, it is not necessary to
do that, because all pm_wakeup_event() calls can use one static timer
that will always be set to expire at the latest time passed to
pm_wakeup_event().

The modifications are based on the example code posted by Alan.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Make it possible to avoid races between wakeup and system sleep

One of the arguments during the suspend blockers discussion was that
the mainline kernel didn't contain any mechanisms making it possible
to avoid races between wakeup and system suspend.

Generally, there are two problems in that area. First, if a wakeup
event occurs exactly when /sys/power/state is being written to, it
may be delivered to user space right before the freezer kicks in, so
the user space consumer of the event may not be able to process it
before the system is suspended. Second, if a wakeup event occurs
after user space has been frozen, it is not generally guaranteed that
the ongoing transition of the system into a sleep state will be
aborted.

To address these issues introduce a new global sysfs attribute,
/sys/power/wakeup_count, associated with a running counter of wakeup
events and three helper functions, pm_stay_awake(), pm_relax(), and
pm_wakeup_event(), that may be used by kernel subsystems to control
the behavior of this attribute and to request the PM core to abort
system transitions into a sleep state already in progress.

The /sys/power/wakeup_count file may be read from or written to by
user space. Reads will always succeed (unless interrupted by a
signal) and return the current value of the wakeup events counter.
Writes, however, will only succeed if the written number is equal to
the current value of the wakeup events counter. If a write is
successful, it will cause the kernel to save the current value of the
wakeup events counter and to abort the subsequent system transition
into a sleep state if any wakeup events are reported after the write
has returned.

[The assumption is that before writing to /sys/power/state user space
will first read from /sys/power/wakeup_count. Next, user space
consumers of wakeup events will have a chance to acknowledge or
veto the upcoming system transition to a sleep state. Finally, if
the transition is allowed to proceed, /sys/power/wakeup_count will
be written to and if that succeeds, /sys/power/state will be written
to as well. Still, if any wakeup events are reported to the PM core
by kernel subsystems after that point, the transition will be
aborted.]

Additionally, put a wakeup events counter into struct dev_pm_info and
make these per-device wakeup event counters available via sysfs,
so that it's possible to check the activity of various wakeup event
sources within the kernel.

To illustrate how subsystems can use pm_wakeup_event(), make the
low-level PCI runtime PM wakeup-handling code use it.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: markgross <markgross@thegnar.org>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>