Message-ID: <CAJZ5v0ghGDys3WuBLtW_BSu_P5aRJQJT4VFoRyuEQWvcUPp9mg@mail.gmail.com>
Date:   Wed, 16 Mar 2022 19:33:55 +0100
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
Cc:     "Rafael J. Wysocki" <rafael@...nel.org>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Jonathan Corbet <corbet@....net>,
        Linux PM <linux-pm@...r.kernel.org>,
        "open list:DOCUMENTATION" <linux-doc@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] documentation: thermal: DPTF Documentation

On Fri, Mar 11, 2022 at 11:14 PM Srinivas Pandruvada
<srinivas.pandruvada@...ux.intel.com> wrote:
>
> Document Intel Dynamic Platform and Thermal Framework (DPTF)
> ABI.
>
> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
> ---
>  Documentation/driver-api/thermal/index.rst    |   1 +
>  .../driver-api/thermal/intel_dptf.rst         | 272 ++++++++++++++++++
>  2 files changed, 273 insertions(+)
>  create mode 100644 Documentation/driver-api/thermal/intel_dptf.rst
>
> diff --git a/Documentation/driver-api/thermal/index.rst b/Documentation/driver-api/thermal/index.rst
> index 4cb0b9b6bfb8..030306ffa408 100644
> --- a/Documentation/driver-api/thermal/index.rst
> +++ b/Documentation/driver-api/thermal/index.rst
> @@ -17,3 +17,4 @@ Thermal
>     intel_powerclamp
>     nouveau_thermal
>     x86_pkg_temperature_thermal
> +   intel_dptf
> diff --git a/Documentation/driver-api/thermal/intel_dptf.rst b/Documentation/driver-api/thermal/intel_dptf.rst
> new file mode 100644
> index 000000000000..96668dca753a
> --- /dev/null
> +++ b/Documentation/driver-api/thermal/intel_dptf.rst
> @@ -0,0 +1,272 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +===============================================================
> +Intel(R) Dynamic Platform and Thermal Framework Sysfs Interface
> +===============================================================
> +
> +:Copyright: |copy| 2022 Intel Corporation
> +
> +:Author: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
> +
> +Introduction
> +------------
> +
> +Intel(R) Dynamic Platform and Thermal Framework (DPTF) is a platform
> +level hardware/software solution for power and thermal management.
> +
> +As a container for multiple power/thermal technologies, DPTF provides
> +a coordinated approach for different policies to effect the hardware
> +state of a system.
> +
> +Since it is a platform level framework, this has several components.
> +Some parts of the technology is implemented in the firmware and uses
> +ACPI and PCI devices to expose various features for monitoring and
> +control. Linux has a set of kernel drivers exposing hardware interface
> +to user space. This allows user space thermal solutions like
> +"Linux Thermal Daemon" to read platform specific thermal and power
> +tables to deliver adequate performance while keeping the system under
> +thermal limits.
> +
> +DPTF ACPI Drivers interface
> +----------------------------
> +
> +:file:`/sys/bus/platform/devices/<N>/uuids`, where <N>
> +=INT3400|INTC1040|INTC1041|INTC10A0
> +
> +``available_uuids`` (RO)
> +       A set of UUIDs strings presenting available policies
> +       which should be notified to the firmware when the
> +       user space can support those policies.
> +
> +       UUID strings:
> +
> +       "42A441D6-AE6A-462b-A84B-4A8CE79027D3" : Passive 1
> +
> +       "3A95C389-E4B8-4629-A526-C52C88626BAE" : Active
> +
> +       "97C68AE7-15FA-499c-B8C9-5DA81D606E0A" : Critical
> +
> +       "63BE270F-1C11-48FD-A6F7-3AF253FF3E2D" : Adaptive performance
> +
> +       "5349962F-71E6-431D-9AE8-0A635B710AEE" : Emergency call
> +
> +       "9E04115A-AE87-4D1C-9500-0F3E340BFE75" : Passive 2
> +
> +       "F5A35014-C209-46A4-993A-EB56DE7530A1" : Power Boss
> +
> +       "6ED722A7-9240-48A5-B479-31EEF723D7CF" : Virtual Sensor
> +
> +       "16CAF1B7-DD38-40ED-B1C1-1B8A1913D531" : Cooling mode
> +
> +       "BE84BABF-C4D4-403D-B495-3128FD44dAC1" : HDC
> +
> +``current_uuid`` (RW)
> +       User space can write strings from available UUIDs, one at a
> +       time.
> +
> +:file:`/sys/bus/platform/devices/<N>/`, where <N>
> +=INT3400|INTC1040|INTC1041|INTC10A0
> +
> +``imok`` (WO)
> +       User space daemon write 1 to respond to firmware event
> +       for sending keep alive notification. User space receives
> +       THERMAL_EVENT_KEEP_ALIVE kobject uevent notification when
> +       firmware calls for user space to respond with imok ACPI
> +       method.
> +
> +``odvp*`` (RO)
> +       Firmware thermal status variable values. Thermal tables
> +       calls for different processing based on these variable
> +       values.
> +
> +``data_vault`` (RO)
> +       Binary thermal table. Refer to
> +       https:/github.com/intel/thermal_daemon for decoding
> +       thermal table.
> +
> +
> +ACPI Thermal Relationship table interface
> +------------------------------------------
> +
> +:file:`/dev/acpi_thermal_rel`
> +
> +       This device provides IOCTL interface to read standard ACPI
> +       thermal relationship tables via ACPI methods _TRT and _ART.
> +       These IOCTLs are defined in
> +       drivers/thermal/intel/int340x_thermal/acpi_thermal_rel.h
> +
> +       IOCTLs:
> +
> +       ACPI_THERMAL_GET_TRT_LEN: Get length of TRT table
> +
> +       ACPI_THERMAL_GET_ART_LEN: Get length of ART table
> +
> +       ACPI_THERMAL_GET_TRT_COUNT: Number of records in TRT table
> +
> +       ACPI_THERMAL_GET_ART_COUNT: Number of records in ART table
> +
> +       ACPI_THERMAL_GET_TRT: Read binary TRT table, length to read is
> +       provided via argument to ioctl().
> +
> +       ACPI_THERMAL_GET_ART: Read binary ART table, length to read is
> +       provided via argument to ioctl().
> +
> +DPTF ACPI Sensor drivers
> +-------------------------
> +
> +DPTF Sensor drivers are presented as standard thermal sysfs thermal_zone.
> +
> +
> +DPTF ACPI Cooling drivers
> +--------------------------
> +
> +DPTF cooling drivers are presented as standard thermal sysfs cooling_device.
> +
> +
> +DPTF Processor thermal PCI Driver interface
> +--------------------------------------------
> +
> +:file:`/sys/bus/pci/devices/0000\:00\:04.0/power_limits/`
> +
> +Refer to Documentation/power/powercap/powercap.rst for powercap
> +ABI.
> +
> +``power_limit_0_max_uw`` (RO)
> +       Maximum powercap sysfs constraint_0_power_limit_uw for Intel RAPL
> +
> +``power_limit_0_step_uw`` (RO)
> +       Power limit increment/decrements for Intel RAPL constraint 0 power limit
> +
> +``power_limit_0_min_uw`` (RO)
> +       Minimum powercap sysfs constraint_0_power_limit_uw for Intel RAPL
> +
> +``power_limit_0_tmin_us`` (RO)
> +       Minimum powercap sysfs constraint_0_time_window_us for Intel RAPL
> +
> +``power_limit_0_tmax_us`` (RO)
> +       Maximum powercap sysfs constraint_0_time_window_us for Intel RAPL
> +
> +``power_limit_1_max_uw`` (RO)
> +       Maximum powercap sysfs constraint_1_power_limit_uw for Intel RAPL
> +
> +``power_limit_1_step_uw`` (RO)
> +       Power limit increment/decrements for Intel RAPL constraint 1 power limit
> +
> +``power_limit_1_min_uw`` (RO)
> +       Minimum powercap sysfs constraint_1_power_limit_uw for Intel RAPL
> +
> +``power_limit_1_tmin_us`` (RO)
> +       Minimum powercap sysfs constraint_1_time_window_us for Intel RAPL
> +
> +``power_limit_1_tmax_us`` (RO)
> +       Maximum powercap sysfs constraint_1_time_window_us for Intel RAPL
> +
> +:file:`/sys/bus/pci/devices/0000\:00\:04.0/`
> +
> +``tcc_offset_degree_celsius`` (RW)
> +       TCC offset from the critical temperature where hardware will throttle
> +       CPU.
> +
> +:file:`/sys/bus/pci/devices/0000\:00\:04.0/workload_request`
> +
> +``workload_available_types`` (RO)
> +       Available workload types. User space can specify one of the workload type
> +       it is currently executing via workload_type. For example: idle, bursty,
> +       sustained etc.
> +
> +``workload_type`` (RW)
> +       User space can specify any one of the available workload type using
> +       this interface.
> +
> +DPTF Processor thermal RFIM interface
> +--------------------------------------------
> +
> +RFIM interface allows adjustment of FIVR (Fully Integrated Voltage Regulator)
> +and DDR (Double Data Rate)frequencies to avoid RF interference with WiFi and 5G.
> +
> +Switching voltage regulators (VR) generate radiated EMI or RFI at the
> +fundamental frequency and its harmonics. Some harmonics may interfere
> +with very sensitive wireless receivers such as Wi-Fi and cellular that
> +are integrated into host systems like notebook PCs.  One of mitigation
> +methods is requesting SOC integrated VR (IVR) switching frequency to a
> +small % and shift away the switching noise harmonic interference from
> +radio channels.  OEM or ODMs can use the driver to control SOC IVR
> +operation within the range where it does not impact IVR performance.
> +
> +DRAM devices of DDR IO interface and their power plane can generate EMI
> +at the data rates. Similar to IVR control mechanism, Intel offers a
> +mechanism by which DDR data rates can be changed if several conditions
> +are met: there is strong RFI interference because of DDR; CPU power
> +management has no other restriction in changing DDR data rates;
> +PC ODMs enable this feature (real time DDR RFI Mitigation referred to as
> +DDR-RFIM) for Wi-Fi from BIOS.
> +
> +
> +FIVR attributes
> +
> +:file:`/sys/bus/pci/devices/0000\:00\:04.0/fivr/`
> +
> +``vco_ref_code_lo`` (RW)
> +       The VCO reference code is an 11-bit field and controls the FIVR
> +       switching frequency. This is the 3-bit LSB field.
> +
> +``vco_ref_code_hi`` (RW)
> +       The VCO reference code is an 11-bit field and controls the FIVR
> +       switching frequency. This is the 8-bit MSB field.
> +
> +``spread_spectrum_pct`` (RW)
> +       Set the FIVR spread spectrum clocking percentage
> +
> +``spread_spectrum_clk_enable`` (RW)
> +       Enable/disable of the FIVR spread spectrum clocking feature
> +
> +``rfi_vco_ref_code`` (RW)
> +       This field is a read only status register which reflects the
> +       current FIVR switching frequency
> +
> +``fivr_fffc_rev`` (RW)
> +       This field indicated the revision of the FIVR HW.
> +
> +
> +DVFS attributes
> +
> +:file:`/sys/bus/pci/devices/0000\:00\:04.0/dvfs/`
> +
> +``rfi_restriction_run_busy`` (RW)
> +       Request the restriction of specific DDR data rate and set this
> +       value 1. Self reset to 0 after operation.
> +
> +``rfi_restriction_err_code`` (RW)
> +       0 :Request is accepted, 1:Feature disabled,
> +       2: the request restricts more points than it is allowed
> +
> +``rfi_restriction_data_rate_Delta`` (RW)
> +       Restricted DDR data rate for RFI protection: Lower Limit
> +
> +``rfi_restriction_data_rate_Base`` (RW)
> +       Restricted DDR data rate for RFI protection: Upper Limit
> +
> +``ddr_data_rate_point_0`` (RO)
> +       DDR data rate selection 1st point
> +
> +``ddr_data_rate_point_1`` (RO)
> +       DDR data rate selection 2nd point
> +
> +``ddr_data_rate_point_2`` (RO)
> +       DDR data rate selection 3rd point
> +
> +``ddr_data_rate_point_3`` (RO)
> +       DDR data rate selection 4th point
> +
> +``rfi_disable (RW)``
> +       Disable DDR rate change feature
> +
> +DPTF Power supply and Battery Interface
> +----------------------------------------
> +
> +Refer to Documentation/ABI/testing/sysfs-platform-dptf
> +
> +DPTF Fan Control
> +----------------------------------------
> +
> +Refer to Documentation/admin-guide/acpi/fan_performance_states.rst
> --

Applied as 5.18 material, thanks!

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