Merge tag 'pm-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management updates from Rafael Wysocki:
 "These clean up and rework the PM QoS API, address a suspend-to-idle
  wakeup regression on some ACPI-based platforms, clean up and extend a
  few cpuidle drivers, update multiple cpufreq drivers and cpufreq
  documentation, and fix a number of issues in devfreq and several other
  things all over.

  Specifics:

   - Clean up and rework the PM QoS API to simplify the code and reduce
     the size of it (Rafael Wysocki).

   - Fix a suspend-to-idle wakeup regression on Dell XPS13 9370 and
     similar platforms where the USB plug/unplug events are handled by
     the EC (Rafael Wysocki).

   - CLean up the intel_idle and PSCI cpuidle drivers (Rafael Wysocki,
     Ulf Hansson).

   - Extend the haltpoll cpuidle driver so that it can be forced to run
     on some systems where it refused to load (Maciej Szmigiero).

   - Convert several cpufreq documents to the .rst format and move the
     legacy driver documentation into one common file (Mauro Carvalho
     Chehab, Rafael Wysocki).

   - Update several cpufreq drivers:

        * Extend and fix the imx-cpufreq-dt driver (Anson Huang).

        * Improve the -EPROBE_DEFER handling and fix unwanted CPU
          overclocking on i.MX6ULL in imx6q-cpufreq (Anson Huang,
          Christoph Niedermaier).

        * Add support for Krait based SoCs to the qcom driver (Ansuel
          Smith).

        * Add support for OPP_PLUS to ti-cpufreq (Lokesh Vutla).

        * Add platform specific intermediate callbacks support to
          cpufreq-dt and update the imx6q driver (Peng Fan).

        * Simplify and consolidate some pieces of the intel_pstate
          driver and update its documentation (Rafael Wysocki, Alex
          Hung).

   - Fix several devfreq issues:

        * Remove unneeded extern keyword from a devfreq header file and
          use the DEVFREQ_GOV_UPDATE_INTERNAL event name instead of
          DEVFREQ_GOV_INTERNAL (Chanwoo Choi).

        * Fix the handling of dev_pm_qos_remove_request() result
          (Leonard Crestez).

        * Use constant name for userspace governor (Pierre Kuo).

        * Get rid of doc warnings and fix a typo (Christophe JAILLET).

   - Use built-in RCU list checking in some places in the PM core to
     avoid false-positive RCU usage warnings (Madhuparna Bhowmik).

   - Add explicit READ_ONCE()/WRITE_ONCE() annotations to low-level PM
     QoS routines (Qian Cai).

   - Fix removal of wakeup sources to avoid NULL pointer dereferences in
     a corner case (Neeraj Upadhyay).

   - Clean up the handling of hibernate compat ioctls and fix the
     related documentation (Eric Biggers).

   - Update the idle_inject power capping driver to use variable-length
     arrays instead of zero-length arrays (Gustavo Silva).

   - Fix list format in a PM QoS document (Randy Dunlap).

   - Make the cpufreq stats module use scnprintf() to avoid potential
     buffer overflows (Takashi Iwai).

   - Add pm_runtime_get_if_active() to PM-runtime API (Sakari Ailus).

   - Allow no domain-idle-states DT property in generic PM domains (Ulf
     Hansson).

   - Fix a broken y-axis scale in the intel_pstate_tracer utility (Doug
     Smythies)"

* tag 'pm-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (78 commits)
  cpufreq: intel_pstate: Simplify intel_pstate_cpu_init()
  tools/power/x86/intel_pstate_tracer: fix a broken y-axis scale
  ACPI: PM: s2idle: Refine active GPEs check
  ACPICA: Allow acpi_any_gpe_status_set() to skip one GPE
  PM: sleep: wakeup: Skip wakeup_source_sysfs_remove() if device is not there
  PM / devfreq: Get rid of some doc warnings
  PM / devfreq: Fix handling dev_pm_qos_remove_request result
  PM / devfreq: Fix a typo in a comment
  PM / devfreq: Change to DEVFREQ_GOV_UPDATE_INTERVAL event name
  PM / devfreq: Remove unneeded extern keyword
  PM / devfreq: Use constant name of userspace governor
  ACPI: PM: s2idle: Fix comment in acpi_s2idle_prepare_late()
  cpufreq: qcom: Add support for krait based socs
  cpufreq: imx6q-cpufreq: Improve the logic of -EPROBE_DEFER handling
  cpufreq: Use scnprintf() for avoiding potential buffer overflow
  cpuidle: psci: Split psci_dt_cpu_init_idle()
  PM / Domains: Allow no domain-idle-states DT property in genpd when parsing
  PM / hibernate: Remove unnecessary compat ioctl overrides
  PM: hibernate: fix docs for ioctls that return loff_t via pointer
  Documentation: intel_pstate: update links for references
  ...

1 files changed, 113 insertions, 0 deletions

diff --git a/Documentation/cpu-freq/core.rst b/Documentation/cpu-freq/core.rst
new file mode 100644
index 000000000000..33cb90bd1d8f
--- /dev/null
+++ b/Documentation/cpu-freq/core.rst
@@ -0,0 +1,113 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=============================================================
+General description of the CPUFreq core and CPUFreq notifiers
+=============================================================
+
+Authors:
+	- Dominik Brodowski  <linux@brodo.de>
+	- David Kimdon <dwhedon@debian.org>
+	- Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+	- Viresh Kumar <viresh.kumar@linaro.org>
+
+.. Contents:
+
+   1.  CPUFreq core and interfaces
+   2.  CPUFreq notifiers
+   3.  CPUFreq Table Generation with Operating Performance Point (OPP)
+
+1. General Information
+======================
+
+The CPUFreq core code is located in drivers/cpufreq/cpufreq.c. This
+cpufreq code offers a standardized interface for the CPUFreq
+architecture drivers (those pieces of code that do actual
+frequency transitions), as well as to "notifiers". These are device
+drivers or other part of the kernel that need to be informed of
+policy changes (ex. thermal modules like ACPI) or of all
+frequency changes (ex. timing code) or even need to force certain
+speed limits (like LCD drivers on ARM architecture). Additionally, the
+kernel "constant" loops_per_jiffy is updated on frequency changes
+here.
+
+Reference counting of the cpufreq policies is done by cpufreq_cpu_get
+and cpufreq_cpu_put, which make sure that the cpufreq driver is
+correctly registered with the core, and will not be unloaded until
+cpufreq_put_cpu is called. That also ensures that the respective cpufreq
+policy doesn't get freed while being used.
+
+2. CPUFreq notifiers
+====================
+
+CPUFreq notifiers conform to the standard kernel notifier interface.
+See linux/include/linux/notifier.h for details on notifiers.
+
+There are two different CPUFreq notifiers - policy notifiers and
+transition notifiers.
+
+
+2.1 CPUFreq policy notifiers
+----------------------------
+
+These are notified when a new policy is created or removed.
+
+The phase is specified in the second argument to the notifier.  The phase is
+CPUFREQ_CREATE_POLICY when the policy is first created and it is
+CPUFREQ_REMOVE_POLICY when the policy is removed.
+
+The third argument, a ``void *pointer``, points to a struct cpufreq_policy
+consisting of several values, including min, max (the lower and upper
+frequencies (in kHz) of the new policy).
+
+
+2.2 CPUFreq transition notifiers
+--------------------------------
+
+These are notified twice for each online CPU in the policy, when the
+CPUfreq driver switches the CPU core frequency and this change has no
+any external implications.
+
+The second argument specifies the phase - CPUFREQ_PRECHANGE or
+CPUFREQ_POSTCHANGE.
+
+The third argument is a struct cpufreq_freqs with the following
+values:
+
+=====	===========================
+cpu	number of the affected CPU
+old	old frequency
+new	new frequency
+flags	flags of the cpufreq driver
+=====	===========================
+
+3. CPUFreq Table Generation with Operating Performance Point (OPP)
+==================================================================
+For details about OPP, see Documentation/power/opp.rst
+
+dev_pm_opp_init_cpufreq_table -
+	This function provides a ready to use conversion routine to translate
+	the OPP layer's internal information about the available frequencies
+	into a format readily providable to cpufreq.
+
+	.. Warning::
+
+	   Do not use this function in interrupt context.
+
+	Example::
+
+	 soc_pm_init()
+	 {
+		/* Do things */
+		r = dev_pm_opp_init_cpufreq_table(dev, &freq_table);
+		if (!r)
+			policy->freq_table = freq_table;
+		/* Do other things */
+	 }
+
+	.. note::
+
+	   This function is available only if CONFIG_CPU_FREQ is enabled in
+	   addition to CONFIG_PM_OPP.
+
+dev_pm_opp_free_cpufreq_table
+	Free up the table allocated by dev_pm_opp_init_cpufreq_table