[PATCH v3 0/1] Interface to represent PAPR firmware attributes

From: Pratik R. Sampat
Date: Mon Jul 12 2021 - 06:52:16 EST


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

Changelog v2 --> v3
Based on a comment from Guatham:
1. Added a versioning check after the H_CALL is made to bail out when
the version from the firmware is inconsistent with that in the kernel

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 hosted here:
https://github.com/pratiksampat/powerpc-utils/tree/H_GET_ENERGY_SCALE_INFO_v2

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 (1):
powerpc/pseries: Interface to represent PAPR firmware attributes

.../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 | 320 ++++++++++++++++++
5 files changed, 372 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

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2.31.1