Merge tag 'acpi-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull ACPI updates from Rafael Wysocki:
 "These rearrange the ACPI documentation by converting it to the .rst
  format and splitting it into clear categories (admin guide, driver
  API, firmware guide), switch over multiple users of a problematic
  library function to a new better one, update the ACPICA code in the
  kernel to a new upstream release, fix a few issues, improve power
  device management diagnostics and do some cleanups.

  Specifics:

   - Convert the ACPI documentation in the kernel source tree to the
     .rst format and split it into the admin guide, driver API and
     firmware guide parts (Changbin Du).

   - Add a PRP0001 usage example to the ACPI documentation (Thomas
     Preston).

   - Switch over the users of the acpi_dev_get_first_match_name()
     library function which turned out to be problematic to a new,
     better one called acpi_dev_get_first_match_dev() (Andy Shevchenko,
     YueHaibing).

   - Update the ACPICA code in the kernel to upstream release 20190405
     including:
       * Null pointer dereference check in acpi_ns_delete_node() (Erik
         Schmauss).
       * Multiple macro and function name changes (Bob Moore).
       * Predefined operation region name fix (Erik Schmauss).

   - Fix hibernation issue on systems using the Baytrail and Cherrytrail
     Intel SoCs introduced during the 4.20 development cycle (Hans de
     Goede).

   - Add Sony VPCEH3U1E to the backlight quirk list (Zhang Rui).

   - Fix button handling during system resume (Zhang Rui).

   - Add a device PM diagnostic message (Rafael Wysocki).

   - Clean up the code, comments and white space in multiple places
     (Bjorn Helgaas, Gustavo Silva, Kefeng Wang)"

* tag 'acpi-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (53 commits)
  Documentation: ACPI: move video_extension.txt to firmware-guide/acpi and convert to reST
  Documentation: ACPI: move ssdt-overlays.txt to admin-guide/acpi and convert to reST
  Documentation: ACPI: move lpit.txt to firmware-guide/acpi and convert to reST
  Documentation: ACPI: move cppc_sysfs.txt to admin-guide/acpi and convert to reST
  Documentation: ACPI: move apei/einj.txt to firmware-guide/acpi and convert to reST
  Documentation: ACPI: move apei/output_format.txt to firmware-guide/acpi and convert to reST
  Documentation: ACPI: move aml-debugger.txt to firmware-guide/acpi and convert to reST
  Documentation: ACPI: move method-tracing.txt to firmware-guide/acpi and convert to rsST
  Documentation: ACPI: move debug.txt to firmware-guide/acpi and convert to reST
  Documentation: ACPI: move dsd/data-node-references.txt to firmware-guide/acpi and convert to reST
  Documentation: ACPI: move dsd/graph.txt to firmware-guide/acpi and convert to reST
  Documentation: ACPI: move acpi-lid.txt to firmware-guide/acpi and convert to reST
  Documentation: ACPI: move i2c-muxes.txt to firmware-guide/acpi and convert to reST
  Documentation: ACPI: move dsdt-override.txt to admin-guide/acpi and convert to reST
  Documentation: ACPI: move initrd_table_override.txt to admin-guide/acpi and convert to reST
  Documentation: ACPI: move method-customizing.txt to firmware-guide/acpi and convert to reST
  Documentation: ACPI: move gpio-properties.txt to firmware-guide/acpi and convert to reST
  Documentation: ACPI: move DSD-properties-rules.txt to firmware-guide/acpi and covert to reST
  Documentation: ACPI: move scan_handlers.txt to driver-api/acpi and convert to reST
  Documentation: ACPI: move linuxized-acpica.txt to driver-api/acpi and convert to reST
  ...

1 files changed, 76 insertions, 0 deletions

diff --git a/Documentation/admin-guide/acpi/cppc_sysfs.rst b/Documentation/admin-guide/acpi/cppc_sysfs.rst
new file mode 100644
index 000000000000..a4b99afbe331
--- /dev/null
+++ b/Documentation/admin-guide/acpi/cppc_sysfs.rst
@@ -0,0 +1,76 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+==================================================
+Collaborative Processor Performance Control (CPPC)
+==================================================
+
+CPPC
+====
+
+CPPC defined in the ACPI spec describes a mechanism for the OS to manage the
+performance of a logical processor on a contigious and abstract performance
+scale. CPPC exposes a set of registers to describe abstract performance scale,
+to request performance levels and to measure per-cpu delivered performance.
+
+For more details on CPPC please refer to the ACPI specification at:
+
+http://uefi.org/specifications
+
+Some of the CPPC registers are exposed via sysfs under::
+
+  /sys/devices/system/cpu/cpuX/acpi_cppc/
+
+for each cpu X::
+
+  $ ls -lR  /sys/devices/system/cpu/cpu0/acpi_cppc/
+  /sys/devices/system/cpu/cpu0/acpi_cppc/:
+  total 0
+  -r--r--r-- 1 root root 65536 Mar  5 19:38 feedback_ctrs
+  -r--r--r-- 1 root root 65536 Mar  5 19:38 highest_perf
+  -r--r--r-- 1 root root 65536 Mar  5 19:38 lowest_freq
+  -r--r--r-- 1 root root 65536 Mar  5 19:38 lowest_nonlinear_perf
+  -r--r--r-- 1 root root 65536 Mar  5 19:38 lowest_perf
+  -r--r--r-- 1 root root 65536 Mar  5 19:38 nominal_freq
+  -r--r--r-- 1 root root 65536 Mar  5 19:38 nominal_perf
+  -r--r--r-- 1 root root 65536 Mar  5 19:38 reference_perf
+  -r--r--r-- 1 root root 65536 Mar  5 19:38 wraparound_time
+
+* highest_perf : Highest performance of this processor (abstract scale).
+* nominal_perf : Highest sustained performance of this processor
+  (abstract scale).
+* lowest_nonlinear_perf : Lowest performance of this processor with nonlinear
+  power savings (abstract scale).
+* lowest_perf : Lowest performance of this processor (abstract scale).
+
+* lowest_freq : CPU frequency corresponding to lowest_perf (in MHz).
+* nominal_freq : CPU frequency corresponding to nominal_perf (in MHz).
+  The above frequencies should only be used to report processor performance in
+  freqency instead of abstract scale. These values should not be used for any
+  functional decisions.
+
+* feedback_ctrs : Includes both Reference and delivered performance counter.
+  Reference counter ticks up proportional to processor's reference performance.
+  Delivered counter ticks up proportional to processor's delivered performance.
+* wraparound_time: Minimum time for the feedback counters to wraparound
+  (seconds).
+* reference_perf : Performance level at which reference performance counter
+  accumulates (abstract scale).
+
+
+Computing Average Delivered Performance
+=======================================
+
+Below describes the steps to compute the average performance delivered by
+taking two different snapshots of feedback counters at time T1 and T2.
+
+  T1: Read feedback_ctrs as fbc_t1
+      Wait or run some workload
+
+  T2: Read feedback_ctrs as fbc_t2
+
+::
+
+  delivered_counter_delta = fbc_t2[del] - fbc_t1[del]
+  reference_counter_delta = fbc_t2[ref] - fbc_t1[ref]
+
+  delivered_perf = (refernce_perf x delivered_counter_delta) / reference_counter_delta