[PATCH v8 0/2] Interface to represent PAPR firmware attributes

[Pratik R. Sampat]

RFC: https://lkml.org/lkml/2021/6/4/791
PATCH v1: https://lkml.org/lkml/2021/6/16/805
PATCH v2: https://lkml.org/lkml/2021/7/6/138
PATCH v3: https://lkml.org/lkml/2021/7/12/2799
PATCH v4: https://lkml.org/lkml/2021/7/16/532
PATCH v5: https://lkml.org/lkml/2021/7/19/247
PATCH v6: https://lkml.org/lkml/2021/7/20/36
PATCH v7: https://lkml.org/lkml/2021/7/23/26 

Changelog v7-->v8
1. Rebased and tested against 5.15
2. Added a selftest to check if the energy and frequency attribues
   exist and their files populated

Also, have implemented a POC using this interface for the powerpc-utils'
ppc64_cpu --frequency command-line tool to utilize this information
in userspace.
The POC for the new interface has been sent to the powerpc-utils mailing
list for early review: https://groups.google.com/g/powerpc-utils-devel/c/r4i7JnlyQ8s

Sample output from the powerpc-utils tool is as follows:

# ppc64_cpu --frequency
Power and Performance Mode: XXXX
Idle Power Saver Status   : XXXX
Processor Folding Status  : XXXX --> Printed if Idle power save status is supported

Platform reported frequencies --> Frequencies reported from the platform's H_CALL i.e PAPR interface
min        :    NNNN GHz
max        :    NNNN GHz
static     :    NNNN GHz

Tool Computed frequencies
min        :    NNNN GHz (cpu XX)
max        :    NNNN GHz (cpu XX)
avg        :    NNNN GHz

Pratik R. Sampat (2):
  powerpc/pseries: Interface to represent PAPR firmware attributes
  selftest/powerpc: Add PAPR sysfs attributes sniff test

 .../sysfs-firmware-papr-energy-scale-info     |  26 ++
 arch/powerpc/include/asm/hvcall.h             |  24 +-
 arch/powerpc/kvm/trace_hv.h                   |   1 +
 arch/powerpc/platforms/pseries/Makefile       |   3 +-
 .../pseries/papr_platform_attributes.c        | 312 ++++++++++++++++++
 tools/testing/selftests/powerpc/Makefile      |   1 +
 .../powerpc/papr_attributes/.gitignore        |   2 +
 .../powerpc/papr_attributes/Makefile          |   7 +
 .../powerpc/papr_attributes/attr_test.c       | 107 ++++++
 9 files changed, 481 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-firmware-papr-energy-scale-info
 create mode 100644 arch/powerpc/platforms/pseries/papr_platform_attributes.c
 create mode 100644 tools/testing/selftests/powerpc/papr_attributes/.gitignore
 create mode 100644 tools/testing/selftests/powerpc/papr_attributes/Makefile
 create mode 100644 tools/testing/selftests/powerpc/papr_attributes/attr_test.c

-- 
2.31.1