From 5bec6cdf92f984cccc09dbe57579760a6e593b79 Mon Sep 17 00:00:00 2001 From: Shilpasri G Bhat Date: Fri, 28 Jul 2017 00:45:29 +0530 Subject: psr: occ: Add support to change power-shifting-ratio Add support to set the CPU-GPU power shifting ratio which is used by the OCC power capping algorithm. PSR value of 100 takes all power away from CPU first and a PSR value of 0 caps GPU first. Documentation enhanced by Stewart Smith. Signed-off-by: Shilpasri G Bhat Signed-off-by: Stewart Smith --- doc/device-tree/ibm,opal/power-mgt/psr.rst | 53 ++++++++++++++++++++ doc/opal-api/opal-power-shift-ratio.rst | 79 ++++++++++++++++++++++++++++++ 2 files changed, 132 insertions(+) create mode 100644 doc/device-tree/ibm,opal/power-mgt/psr.rst create mode 100644 doc/opal-api/opal-power-shift-ratio.rst (limited to 'doc') diff --git a/doc/device-tree/ibm,opal/power-mgt/psr.rst b/doc/device-tree/ibm,opal/power-mgt/psr.rst new file mode 100644 index 0000000..edae8da --- /dev/null +++ b/doc/device-tree/ibm,opal/power-mgt/psr.rst @@ -0,0 +1,53 @@ +power-mgt/psr +------------------ + +Some systems allow modification of how power consumption throttling +is balanced between entities in a system. A typical one may be how the power +management complex should balance throttling CPU versus the GPU. An OPAL +call can be used to set these ratios, which are described in the device +tree. + +In the future, there may be more available settings than just CPU +versus GPU. + +Each child node in the "psr" node represents a configurable psr +sensor. + +For example : :: + cpu-to-gpu@1 + +The compatible property is set to "ibm,opal-power-shift-ratio". + +Each child node has below properties: + +`handle` + Handle to indicate the type of psr + +`label` + Name of the psr sensor + +The format of the handle is internal, and ``not`` ABI, although +currently it uses the following encoding :: + + | Class |Reserved| RID | Type | + |-------|--------|------|------| + +.. code-block:: dts + + power-mgt { + psr { + compatible = "ibm,opal-power-shift-ratio" + + cpu-to-gpu@0 { + name = "cpu-to-gpu" + handle = <0x00000000> + label = "cpu_to_gpu_0" + }; + + cpu-to-gpu@1 { + name = "cpu-to-gpu" + handle = <0x00000100> + label = "cpu_to_gpu_1" + }; + }; + }; diff --git a/doc/opal-api/opal-power-shift-ratio.rst b/doc/opal-api/opal-power-shift-ratio.rst new file mode 100644 index 0000000..7f1f71f --- /dev/null +++ b/doc/opal-api/opal-power-shift-ratio.rst @@ -0,0 +1,79 @@ +.. _opal-psr: + +OPAL_GET_POWER_SHIFT_RATIO +============================== +OPAL call to read the power-shifting-ratio using a handle to identify +the type (e.g CPU vs. GPU, CPU vs. MEM) which is exported via +device-tree. + +The call can be asynchronus, where the token parameter is used to wait +for the completion. + +Parameters +---------- +:: + u32 handle + int token + u32 *ratio + +Returns +------- +OPAL_SUCCESS + Success + +OPAL_PARAMETER + Invalid ratio pointer + +OPAL_UNSUPPORTED + No support for reading psr + +OPAL_HARDWARE + Unable to procced due to the current hardware state + +OPAL_ASYNC_COMPLETION + Request was sent and an async completion message will be sent with + token and status of the request. + +OPAL_SET_POWER_SHIFT_RATIO +============================== +OPAL call to set power-shifting-ratio using a handle to identify +the type of PSR which is exported in device-tree. This call can be +asynchronus where the token parameter is used to wait for the +completion. + +Parameters +---------- +:: + u32 handle + int token + u32 ratio + +Returns +------- +OPAL_SUCCESS + Success + +OPAL_PARAMETER + Invalid ratio requested + +OPAL_UNSUPPORTED + No support for changing the ratio + +OPAL_PERMISSION + Hardware cannot take the request + +OPAL_ASYNC_COMPLETION + Request was sent and an async completion message will be sent with + token and status of the request. + +OPAL_HARDWARE + Unable to procced due to the current hardware state + +OPAL_BUSY + Previous request in progress + +OPAL_INTERNAL_ERROR + Error in request response + +OPAL_TIMEOUT + Timeout in request completion -- cgit v1.1