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, 136 insertions, 0 deletions

diff --git a/Documentation/cpu-freq/cpufreq-stats.rst b/Documentation/cpu-freq/cpufreq-stats.rst
new file mode 100644
index 000000000000..9ad695b1c7db
--- /dev/null
+++ b/Documentation/cpu-freq/cpufreq-stats.rst
@@ -0,0 +1,136 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+==========================================
+General Description of sysfs CPUFreq Stats
+==========================================
+
+information for users
+
+
+Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
+
+.. Contents
+
+   1. Introduction
+   2. Statistics Provided (with example)
+   3. Configuring cpufreq-stats
+
+
+1. Introduction
+===============
+
+cpufreq-stats is a driver that provides CPU frequency statistics for each CPU.
+These statistics are provided in /sysfs as a bunch of read_only interfaces. This
+interface (when configured) will appear in a separate directory under cpufreq
+in /sysfs (<sysfs root>/devices/system/cpu/cpuX/cpufreq/stats/) for each CPU.
+Various statistics will form read_only files under this directory.
+
+This driver is designed to be independent of any particular cpufreq_driver
+that may be running on your CPU. So, it will work with any cpufreq_driver.
+
+
+2. Statistics Provided (with example)
+=====================================
+
+cpufreq stats provides following statistics (explained in detail below).
+
+-  time_in_state
+-  total_trans
+-  trans_table
+
+All the statistics will be from the time the stats driver has been inserted
+(or the time the stats were reset) to the time when a read of a particular
+statistic is done. Obviously, stats driver will not have any information
+about the frequency transitions before the stats driver insertion.
+
+::
+
+    <mysystem>:/sys/devices/system/cpu/cpu0/cpufreq/stats # ls -l
+    total 0
+    drwxr-xr-x  2 root root    0 May 14 16:06 .
+    drwxr-xr-x  3 root root    0 May 14 15:58 ..
+    --w-------  1 root root 4096 May 14 16:06 reset
+    -r--r--r--  1 root root 4096 May 14 16:06 time_in_state
+    -r--r--r--  1 root root 4096 May 14 16:06 total_trans
+    -r--r--r--  1 root root 4096 May 14 16:06 trans_table
+
+- **reset**
+
+Write-only attribute that can be used to reset the stat counters. This can be
+useful for evaluating system behaviour under different governors without the
+need for a reboot.
+
+- **time_in_state**
+
+This gives the amount of time spent in each of the frequencies supported by
+this CPU. The cat output will have "<frequency> <time>" pair in each line, which
+will mean this CPU spent <time> usertime units of time at <frequency>. Output
+will have one line for each of the supported frequencies. usertime units here
+is 10mS (similar to other time exported in /proc).
+
+::
+
+    <mysystem>:/sys/devices/system/cpu/cpu0/cpufreq/stats # cat time_in_state
+    3600000 2089
+    3400000 136
+    3200000 34
+    3000000 67
+    2800000 172488
+
+
+- **total_trans**
+
+This gives the total number of frequency transitions on this CPU. The cat
+output will have a single count which is the total number of frequency
+transitions.
+
+::
+
+    <mysystem>:/sys/devices/system/cpu/cpu0/cpufreq/stats # cat total_trans
+    20
+
+- **trans_table**
+
+This will give a fine grained information about all the CPU frequency
+transitions. The cat output here is a two dimensional matrix, where an entry
+<i,j> (row i, column j) represents the count of number of transitions from
+Freq_i to Freq_j. Freq_i rows and Freq_j columns follow the sorting order in
+which the driver has provided the frequency table initially to the cpufreq core
+and so can be sorted (ascending or descending) or unsorted.  The output here
+also contains the actual freq values for each row and column for better
+readability.
+
+If the transition table is bigger than PAGE_SIZE, reading this will
+return an -EFBIG error.
+
+::
+
+    <mysystem>:/sys/devices/system/cpu/cpu0/cpufreq/stats # cat trans_table
+    From  :    To
+	    :   3600000   3400000   3200000   3000000   2800000
+    3600000:         0         5         0         0         0
+    3400000:         4         0         2         0         0
+    3200000:         0         1         0         2         0
+    3000000:         0         0         1         0         3
+    2800000:         0         0         0         2         0
+
+3. Configuring cpufreq-stats
+============================
+
+To configure cpufreq-stats in your kernel::
+
+	Config Main Menu
+		Power management options (ACPI, APM)  --->
+			CPU Frequency scaling  --->
+				[*] CPU Frequency scaling
+				[*]   CPU frequency translation statistics
+
+
+"CPU Frequency scaling" (CONFIG_CPU_FREQ) should be enabled to configure
+cpufreq-stats.
+
+"CPU frequency translation statistics" (CONFIG_CPU_FREQ_STAT) provides the
+statistics which includes time_in_state, total_trans and trans_table.
+
+Once this option is enabled and your CPU supports cpufrequency, you
+will be able to see the CPU frequency statistics in /sysfs.