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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 | ||
| devicetree | ||
| doc-guide | ||
| driver-api | ||
| fault-injection | ||
| fb | ||
| features | ||
| filesystems | ||
| firmware-guide | ||
| firmware_class | ||
| fpga | ||
| gpu | ||
| hid | ||
| hwmon | ||
| i2c | ||
| ia64 | ||
| ide | ||
| iio | ||
| infiniband | ||
| input | ||
| isdn | ||
| kbuild | ||
| kernel-hacking | ||
| leds | ||
| litmus-tests | ||
| livepatch | ||
| locking | ||
| m68k | ||
| maintainer | ||
| mhi | ||
| mips | ||
| misc-devices | ||
| netlabel | ||
| networking | ||
| nios2 | ||
| nvdimm | ||
| openrisc | ||
| parisc | ||
| PCI | ||
| pcmcia | ||
| power | ||
| powerpc | ||
| process | ||
| RCU | ||
| riscv | ||
| s390 | ||
| scheduler | ||
| scsi | ||
| security | ||
| sh | ||
| sound | ||
| sparc | ||
| sphinx | ||
| sphinx-static | ||
| spi | ||
| staging | ||
| target | ||
| timers | ||
| tools | ||
| trace | ||
| translations | ||
| tty | ||
| usb | ||
| userspace-api | ||
| virt | ||
| vm | ||
| w1 | ||
| watchdog | ||
| x86 | ||
| xtensa | ||
| .gitignore | ||
| arch.rst | ||
| asm-annotations.rst | ||
| atomic_bitops.txt | ||
| atomic_t.txt | ||
| Changes | ||
| CodingStyle | ||
| conf.py | ||
| COPYING-logo | ||
| docutils.conf | ||
| dontdiff | ||
| index.rst | ||
| Kconfig | ||
| logo.gif | ||
| Makefile | ||
| memory-barriers.txt | ||
| SubmittingPatches | ||
| watch_queue.rst | ||
