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1.. SPDX-License-Identifier: GPL-2.0
2
3===============================================================
4Intel(R) Dynamic Platform and Thermal Framework Sysfs Interface
5===============================================================
6
7:Copyright: © 2022 Intel Corporation
8
9:Author: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
10
11Introduction
12------------
13
14Intel(R) Dynamic Platform and Thermal Framework (DPTF) is a platform
15level hardware/software solution for power and thermal management.
16
17As a container for multiple power/thermal technologies, DPTF provides
18a coordinated approach for different policies to effect the hardware
19state of a system.
20
21Since it is a platform level framework, this has several components.
22Some parts of the technology is implemented in the firmware and uses
23ACPI and PCI devices to expose various features for monitoring and
24control. Linux has a set of kernel drivers exposing hardware interface
25to user space. This allows user space thermal solutions like
26"Linux Thermal Daemon" to read platform specific thermal and power
27tables to deliver adequate performance while keeping the system under
28thermal limits.
29
30DPTF ACPI Drivers interface
31----------------------------
32
33:file:`/sys/bus/platform/devices/<N>/uuids`, where <N>
34=INT3400|INTC1040|INTC1041|INTC10A0
35
36``available_uuids`` (RO)
37 A set of UUIDs strings presenting available policies
38 which should be notified to the firmware when the
39 user space can support those policies.
40
41 UUID strings:
42
43 "42A441D6-AE6A-462b-A84B-4A8CE79027D3" : Passive 1
44
45 "3A95C389-E4B8-4629-A526-C52C88626BAE" : Active
46
47 "97C68AE7-15FA-499c-B8C9-5DA81D606E0A" : Critical
48
49 "63BE270F-1C11-48FD-A6F7-3AF253FF3E2D" : Adaptive performance
50
51 "5349962F-71E6-431D-9AE8-0A635B710AEE" : Emergency call
52
53 "9E04115A-AE87-4D1C-9500-0F3E340BFE75" : Passive 2
54
55 "F5A35014-C209-46A4-993A-EB56DE7530A1" : Power Boss
56
57 "6ED722A7-9240-48A5-B479-31EEF723D7CF" : Virtual Sensor
58
59 "16CAF1B7-DD38-40ED-B1C1-1B8A1913D531" : Cooling mode
60
61 "BE84BABF-C4D4-403D-B495-3128FD44dAC1" : HDC
62
63``current_uuid`` (RW)
64 User space can write strings from available UUIDs, one at a
65 time.
66
67:file:`/sys/bus/platform/devices/<N>/`, where <N>
68=INT3400|INTC1040|INTC1041|INTC10A0
69
70``imok`` (WO)
71 User space daemon write 1 to respond to firmware event
72 for sending keep alive notification. User space receives
73 THERMAL_EVENT_KEEP_ALIVE kobject uevent notification when
74 firmware calls for user space to respond with imok ACPI
75 method.
76
77``odvp*`` (RO)
78 Firmware thermal status variable values. Thermal tables
79 calls for different processing based on these variable
80 values.
81
82``data_vault`` (RO)
83 Binary thermal table. Refer to
84 https:/github.com/intel/thermal_daemon for decoding
85 thermal table.
86
87``production_mode`` (RO)
88 When different from zero, manufacturer locked thermal configuration
89 from further changes.
90
91ACPI Thermal Relationship table interface
92------------------------------------------
93
94:file:`/dev/acpi_thermal_rel`
95
96 This device provides IOCTL interface to read standard ACPI
97 thermal relationship tables via ACPI methods _TRT and _ART.
98 These IOCTLs are defined in
99 drivers/thermal/intel/int340x_thermal/acpi_thermal_rel.h
100
101 IOCTLs:
102
103 ACPI_THERMAL_GET_TRT_LEN: Get length of TRT table
104
105 ACPI_THERMAL_GET_ART_LEN: Get length of ART table
106
107 ACPI_THERMAL_GET_TRT_COUNT: Number of records in TRT table
108
109 ACPI_THERMAL_GET_ART_COUNT: Number of records in ART table
110
111 ACPI_THERMAL_GET_TRT: Read binary TRT table, length to read is
112 provided via argument to ioctl().
113
114 ACPI_THERMAL_GET_ART: Read binary ART table, length to read is
115 provided via argument to ioctl().
116
117DPTF ACPI Sensor drivers
118-------------------------
119
120DPTF Sensor drivers are presented as standard thermal sysfs thermal_zone.
121
122
123DPTF ACPI Cooling drivers
124--------------------------
125
126DPTF cooling drivers are presented as standard thermal sysfs cooling_device.
127
128
129DPTF Processor thermal PCI Driver interface
130--------------------------------------------
131
132:file:`/sys/bus/pci/devices/0000\:00\:04.0/power_limits/`
133
134Refer to Documentation/power/powercap/powercap.rst for powercap
135ABI.
136
137``power_limit_0_max_uw`` (RO)
138 Maximum powercap sysfs constraint_0_power_limit_uw for Intel RAPL
139
140``power_limit_0_step_uw`` (RO)
141 Power limit increment/decrements for Intel RAPL constraint 0 power limit
142
143``power_limit_0_min_uw`` (RO)
144 Minimum powercap sysfs constraint_0_power_limit_uw for Intel RAPL
145
146``power_limit_0_tmin_us`` (RO)
147 Minimum powercap sysfs constraint_0_time_window_us for Intel RAPL
148
149``power_limit_0_tmax_us`` (RO)
150 Maximum powercap sysfs constraint_0_time_window_us for Intel RAPL
151
152``power_limit_1_max_uw`` (RO)
153 Maximum powercap sysfs constraint_1_power_limit_uw for Intel RAPL
154
155``power_limit_1_step_uw`` (RO)
156 Power limit increment/decrements for Intel RAPL constraint 1 power limit
157
158``power_limit_1_min_uw`` (RO)
159 Minimum powercap sysfs constraint_1_power_limit_uw for Intel RAPL
160
161``power_limit_1_tmin_us`` (RO)
162 Minimum powercap sysfs constraint_1_time_window_us for Intel RAPL
163
164``power_limit_1_tmax_us`` (RO)
165 Maximum powercap sysfs constraint_1_time_window_us for Intel RAPL
166
167``power_floor_status`` (RO)
168 When set to 1, the power floor of the system in the current
169 configuration has been reached. It needs to be reconfigured to allow
170 power to be reduced any further.
171
172``power_floor_enable`` (RW)
173 When set to 1, enable reading and notification of the power floor
174 status. Notifications are triggered for the power_floor_status
175 attribute value changes.
176
177:file:`/sys/bus/pci/devices/0000\:00\:04.0/`
178
179``tcc_offset_degree_celsius`` (RW)
180 TCC offset from the critical temperature where hardware will throttle
181 CPU.
182
183:file:`/sys/bus/pci/devices/0000\:00\:04.0/workload_request`
184
185``workload_available_types`` (RO)
186 Available workload types. User space can specify one of the workload type
187 it is currently executing via workload_type. For example: idle, bursty,
188 sustained etc.
189
190``workload_type`` (RW)
191 User space can specify any one of the available workload type using
192 this interface.
193
194DPTF Processor thermal RFIM interface
195--------------------------------------------
196
197RFIM interface allows adjustment of FIVR (Fully Integrated Voltage Regulator),
198DDR (Double Data Rate) and DLVR (Digital Linear Voltage Regulator)
199frequencies to avoid RF interference with WiFi and 5G.
200
201Switching voltage regulators (VR) generate radiated EMI or RFI at the
202fundamental frequency and its harmonics. Some harmonics may interfere
203with very sensitive wireless receivers such as Wi-Fi and cellular that
204are integrated into host systems like notebook PCs. One of mitigation
205methods is requesting SOC integrated VR (IVR) switching frequency to a
206small % and shift away the switching noise harmonic interference from
207radio channels. OEM or ODMs can use the driver to control SOC IVR
208operation within the range where it does not impact IVR performance.
209
210Some products use DLVR instead of FIVR as switching voltage regulator.
211In this case attributes of DLVR must be adjusted instead of FIVR.
212
213While shifting the frequencies additional clock noise can be introduced,
214which is compensated by adjusting Spread spectrum percent. This helps
215to reduce the clock noise to meet regulatory compliance. This spreading
216% increases bandwidth of signal transmission and hence reduces the
217effects of interference, noise and signal fading.
218
219DRAM devices of DDR IO interface and their power plane can generate EMI
220at the data rates. Similar to IVR control mechanism, Intel offers a
221mechanism by which DDR data rates can be changed if several conditions
222are met: there is strong RFI interference because of DDR; CPU power
223management has no other restriction in changing DDR data rates;
224PC ODMs enable this feature (real time DDR RFI Mitigation referred to as
225DDR-RFIM) for Wi-Fi from BIOS.
226
227
228FIVR attributes
229
230:file:`/sys/bus/pci/devices/0000\:00\:04.0/fivr/`
231
232``vco_ref_code_lo`` (RW)
233 The VCO reference code is an 11-bit field and controls the FIVR
234 switching frequency. This is the 3-bit LSB field.
235
236``vco_ref_code_hi`` (RW)
237 The VCO reference code is an 11-bit field and controls the FIVR
238 switching frequency. This is the 8-bit MSB field.
239
240``spread_spectrum_pct`` (RW)
241 Set the FIVR spread spectrum clocking percentage
242
243``spread_spectrum_clk_enable`` (RW)
244 Enable/disable of the FIVR spread spectrum clocking feature
245
246``rfi_vco_ref_code`` (RW)
247 This field is a read only status register which reflects the
248 current FIVR switching frequency
249
250``fivr_fffc_rev`` (RW)
251 This field indicated the revision of the FIVR HW.
252
253
254DVFS attributes
255
256:file:`/sys/bus/pci/devices/0000\:00\:04.0/dvfs/`
257
258``rfi_restriction_run_busy`` (RW)
259 Request the restriction of specific DDR data rate and set this
260 value 1. Self reset to 0 after operation.
261
262``rfi_restriction_err_code`` (RW)
263 0 :Request is accepted, 1:Feature disabled,
264 2: the request restricts more points than it is allowed
265
266``rfi_restriction_data_rate_Delta`` (RW)
267 Restricted DDR data rate for RFI protection: Lower Limit
268
269``rfi_restriction_data_rate_Base`` (RW)
270 Restricted DDR data rate for RFI protection: Upper Limit
271
272``ddr_data_rate_point_0`` (RO)
273 DDR data rate selection 1st point
274
275``ddr_data_rate_point_1`` (RO)
276 DDR data rate selection 2nd point
277
278``ddr_data_rate_point_2`` (RO)
279 DDR data rate selection 3rd point
280
281``ddr_data_rate_point_3`` (RO)
282 DDR data rate selection 4th point
283
284``rfi_disable (RW)``
285 Disable DDR rate change feature
286
287DLVR attributes
288
289:file:`/sys/bus/pci/devices/0000\:00\:04.0/dlvr/`
290
291``dlvr_hardware_rev`` (RO)
292 DLVR hardware revision.
293
294``dlvr_freq_mhz`` (RO)
295 Current DLVR PLL frequency in MHz.
296
297``dlvr_freq_select`` (RW)
298 Sets DLVR PLL clock frequency. Once set, and enabled via
299 dlvr_rfim_enable, the dlvr_freq_mhz will show the current
300 DLVR PLL frequency.
301
302``dlvr_pll_busy`` (RO)
303 PLL can't accept frequency change when set.
304
305``dlvr_rfim_enable`` (RW)
306 0: Disable RF frequency hopping, 1: Enable RF frequency hopping.
307
308``dlvr_spread_spectrum_pct`` (RW)
309 Sets DLVR spread spectrum percent value.
310
311``dlvr_control_mode`` (RW)
312 Specifies how frequencies are spread using spread spectrum.
313 0: Down spread,
314 1: Spread in the Center.
315
316``dlvr_control_lock`` (RW)
317 1: future writes are ignored.
318
319DPTF Power supply and Battery Interface
320----------------------------------------
321
322Refer to Documentation/ABI/testing/sysfs-platform-dptf
323
324DPTF Fan Control
325----------------------------------------
326
327Refer to Documentation/admin-guide/acpi/fan_performance_states.rst
328
329Workload Type Hints
330----------------------------------------
331
332The firmware in Meteor Lake processor generation is capable of identifying
333workload type and passing hints regarding it to the OS. A special sysfs
334interface is provided to allow user space to obtain workload type hints from
335the firmware and control the rate at which they are provided.
336
337User space can poll attribute "workload_type_index" for the current hint or
338can receive a notification whenever the value of this attribute is updated.
339
340file:`/sys/bus/pci/devices/0000:00:04.0/workload_hint/`
341Segment 0, bus 0, device 4, function 0 is reserved for the processor thermal
342device on all Intel client processors. So, the above path doesn't change
343based on the processor generation.
344
345``workload_hint_enable`` (RW)
346 Enable firmware to send workload type hints to user space.
347
348``notification_delay_ms`` (RW)
349 Minimum delay in milliseconds before firmware will notify OS. This is
350 for the rate control of notifications. This delay is between changing
351 the workload type prediction in the firmware and notifying the OS about
352 the change. The default delay is 1024 ms. The delay of 0 is invalid.
353 The delay is rounded up to the nearest power of 2 to simplify firmware
354 programming of the delay value. The read of notification_delay_ms
355 attribute shows the effective value used.
356
357``workload_type_index`` (RO)
358 Predicted workload type index. User space can get notification of
359 change via existing sysfs attribute change notification mechanism.
360
361 The supported index values and their meaning for the Meteor Lake
362 processor generation are as follows:
363
364 0 - Idle: System performs no tasks, power and idle residency are
365 consistently low for long periods of time.
366
367 1 – Battery Life: Power is relatively low, but the processor may
368 still be actively performing a task, such as video playback for
369 a long period of time.
370
371 2 – Sustained: Power level that is relatively high for a long period
372 of time, with very few to no periods of idleness, which will
373 eventually exhaust RAPL Power Limit 1 and 2.
374
375 3 – Bursty: Consumes a relatively constant average amount of power, but
376 periods of relative idleness are interrupted by bursts of
377 activity. The bursts are relatively short and the periods of
378 relative idleness between them typically prevent RAPL Power
379 Limit 1 from being exhausted.
380
381 4 – Unknown: Can't classify.