RFC: https://lkml.org/lkml/2021/6/4/791 PATCH v1: https://lkml.org/lkml/2021/6/16/805 Changelog v1 --> v2 Based on comments from Fabiano and Gautham, the following changes were made: 1. Added flag attributes to fetch either single or all attributes from the H_GET_ENERGY_SCALE_INFO HCALL 2. Seperated the header and the attribute structs, therfore allocating for them through a single abstract buffer and later parsing them into their own structures based on the offset 3. Renamed Energy Management(em) prefixed variables to energy scale attributes(esi) prefixed variables to maintain consistency. 4. Removed bailing on version checks as to avoid faliure in future versions which can be backwards compatible 5. Moved check for FW_FEATURE_LPAR before the HCALL is made to save cycles and allocations on an event of faliure 6. Updated descriptions and comments 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 | 23 +- arch/powerpc/kvm/trace_hv.h | 1 + arch/powerpc/platforms/pseries/Makefile | 3 +- .../pseries/papr_platform_attributes.c | 320 ++++++++++++++++++ 5 files changed, 371 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 -- 2.31.1
