linux-kernel - [PATCH v2 0/7] CPPC optional registers AMD support

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Date:   Thu, 4 Apr 2019 21:25:43 +0000
From:   "Natarajan, Janakarajan" <Janakarajan.Natarajan@....com>
To:     "linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "devel@...ica.org" <devel@...ica.org>
CC:     "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Len Brown <lenb@...nel.org>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Robert Moore <robert.moore@...el.com>,
        Erik Schmauss <erik.schmauss@...el.com>,
        "Ghannam, Yazen" <Yazen.Ghannam@....com>,
        "Natarajan, Janakarajan" <Janakarajan.Natarajan@....com>
Subject: [PATCH v2 0/7] CPPC optional registers AMD support

CPPC (Collaborative Processor Performance Control) offers optional
registers which can be used to tune the system based on energy and/or
performance requirements.

Newer AMD processors add support for a subset of these optional CPPC
registers, based on ACPI v6.1.

The following are the supported CPPC registers for which sysfs entries
are created:
* enable                (NEW)
* max_perf              (NEW)
* min_perf              (NEW)
* energy_perf
* lowest_perf
* nominal_perf
* desired_perf          (NEW)
* feedback_ctrs
* auto_sel_enable       (NEW)
* lowest_nonlinear_perf

The CPPC driver is updated to enable the OSPM and the userspace to
access
the newly supported registers.

The purpose of exposing the registers via the sysfs entries is to allow
the userspace to:
* Tweak the values to fit its workload.
* Apply a profile from AMD's optimization guides.

Profiles will be documented in the performance/optimization guides.

Note:
* AMD systems will not have a policy applied in the kernel at this time.
* By default, acpi_cpufreq will still be used.

TODO:
* Create a linux userspace tool that will help users generate a CPPC
* profile
  for their target workload.
* Create or update a driver to apply a general CPPC policy in the
* kernel.

v1->v2:
* Add macro to ensure BUFFER only registers have BUFFER type.
* Add support macro to make the right check based on register type.
* Remove support checks for registers which are mandatory.

Janakarajan Natarajan (2):
  acpi/cppc: Add macro for CPPC register BUFFER only check
  acpi/cppc: Ensure only supported CPPC sysfs entries are created

Yazen Ghannam (5):
  acpi/cppc: Modify show_cppc_data macro
  acpi/cppc: Rework cppc_set_perf() to use cppc_regs index
  acpi/cppc: Add macros to define a R/W sysfs entry for CPPC registers
  acpi/cppc: Add support for optional CPPC registers
  acpi/cppc: Add support for CPPC Enable register

 drivers/acpi/cppc_acpi.c       | 402 +++++++++++++++++++++++++++++----
 drivers/cpufreq/cppc_cpufreq.c |   6 +-
 include/acpi/cppc_acpi.h       |   6 +-
 3 files changed, 372 insertions(+), 42 deletions(-)

-- 
2.17.1