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3c14b73454
Adds a syscall interface to represent the energy and frequency related PAPR attributes on the system using the new H_CALL "H_GET_ENERGY_SCALE_INFO". H_GET_EM_PARMS H_CALL was previously responsible for exporting this information in the lparcfg, however the H_GET_EM_PARMS H_CALL will be deprecated P10 onwards. The H_GET_ENERGY_SCALE_INFO H_CALL is of the following call format: hcall( uint64 H_GET_ENERGY_SCALE_INFO, // Get energy scale info uint64 flags, // Per the flag request uint64 firstAttributeId,// The attribute id uint64 bufferAddress, // Guest physical address of the output buffer uint64 bufferSize // The size in bytes of the output buffer ); As specified in PAPR+ v2.11, section 14.14.3. This H_CALL can query either all the attributes at once with firstAttributeId = 0, flags = 0 as well as query only one attribute at a time with firstAttributeId = id, flags = 1. The output buffer consists of the following 1. number of attributes - 8 bytes 2. array offset to the data location - 8 bytes 3. version info - 1 byte 4. A data array of size num attributes, which contains the following: a. attribute ID - 8 bytes b. attribute value in number - 8 bytes c. attribute name in string - 64 bytes d. attribute value in string - 64 bytes The new H_CALL exports information in direct string value format, hence a new interface has been introduced in /sys/firmware/papr/energy_scale_info to export this information to userspace so that the firmware can add new values without the need for the kernel to be changed. The H_CALL returns the name, numeric value and string value (if exists) The format of exposing the sysfs information is as follows: /sys/firmware/papr/energy_scale_info/ |-- <id>/ |-- desc |-- value |-- value_desc (if exists) |-- <id>/ |-- desc |-- value |-- value_desc (if exists) ... The energy information that is exported is useful for userspace tools such as powerpc-utils. Currently these tools infer the "power_mode_data" value in the lparcfg, which in turn is obtained from the to be deprecated H_GET_EM_PARMS H_CALL. On future platforms, such userspace utilities will have to look at the data returned from the new H_CALL being populated in this new sysfs interface and report this information directly without the need of interpretation. Signed-off-by: Pratik R. Sampat <psampat@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220217105321.52941-2-psampat@linux.ibm.com |
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ABI | ||
accounting | ||
admin-guide | ||
arc | ||
arm | ||
arm64 | ||
block | ||
bpf | ||
cdrom | ||
core-api | ||
cpu-freq | ||
crypto | ||
dev-tools | ||
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doc-guide | ||
driver-api | ||
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filesystems | ||
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hwmon | ||
i2c | ||
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x86 | ||
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.gitignore | ||
arch.rst | ||
asm-annotations.rst | ||
atomic_bitops.txt | ||
atomic_t.txt | ||
Changes | ||
CodingStyle | ||
conf.py | ||
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docutils.conf | ||
dontdiff | ||
index.rst | ||
Kconfig | ||
logo.gif | ||
Makefile | ||
memory-barriers.txt | ||
SubmittingPatches | ||
watch_queue.rst |