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-rw-r--r--Documentation/wmi/acpi-interface.rst96
-rw-r--r--Documentation/wmi/devices/dell-wmi-ddv.rst297
-rw-r--r--Documentation/wmi/devices/index.rst22
-rw-r--r--Documentation/wmi/devices/wmi-bmof.rst25
-rw-r--r--Documentation/wmi/index.rst19
5 files changed, 459 insertions, 0 deletions
diff --git a/Documentation/wmi/acpi-interface.rst b/Documentation/wmi/acpi-interface.rst
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+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+==================
+ACPI WMI interface
+==================
+
+The ACPI WMI interface is a proprietary extension of the ACPI specification made
+by Microsoft to allow hardware vendors to embed WMI (Windows Management Instrumentation)
+objects inside their ACPI firmware. Typical functions implemented over ACPI WMI
+are hotkey events on modern notebooks and configuration of BIOS options.
+
+PNP0C14 ACPI device
+-------------------
+
+Discovery of WMI objects is handled by defining ACPI devices with a PNP ID
+of ``PNP0C14``. These devices will contain a set of ACPI buffers and methods
+used for mapping and execution of WMI methods and/or queries. If there exist
+multiple of such devices, then each device is required to have a
+unique ACPI UID.
+
+_WDG buffer
+-----------
+
+The ``_WDG`` buffer is used to discover WMI objects and is required to be
+static. Its internal structure consists of data blocks with a size of 20 bytes,
+containing the following data:
+
+======= =============== =====================================================
+Offset Size (in bytes) Content
+======= =============== =====================================================
+0x00 16 128 bit Variant 2 object GUID.
+0x10 2 2 character method ID or single byte notification ID.
+0x12 1 Object instance count.
+0x13 1 Object flags.
+======= =============== =====================================================
+
+The WMI object flags control whether the method or notification ID is used:
+
+- 0x1: Data block usage is expensive and must be explicitly enabled/disabled.
+- 0x2: Data block contains WMI methods.
+- 0x4: Data block contains ASCIZ string.
+- 0x8: Data block describes a WMI event, use notification ID instead
+ of method ID.
+
+Each WMI object GUID can appear multiple times inside a system.
+The method/notification ID is used to construct the ACPI method names used for
+interacting with the WMI object.
+
+WQxx ACPI methods
+-----------------
+
+If a data block does not contain WMI methods, then its content can be retrieved
+by this required ACPI method. The last two characters of the ACPI method name
+are the method ID of the data block to query. Their single parameter is an
+integer describing the instance which should be queried. This parameter can be
+omitted if the data block contains only a single instance.
+
+WSxx ACPI methods
+-----------------
+
+Similar to the ``WQxx`` ACPI methods, except that it is optional and takes an
+additional buffer as its second argument. The instance argument also cannot
+be omitted.
+
+WMxx ACPI methods
+-----------------
+
+Used for executing WMI methods associated with a data block. The last two
+characters of the ACPI method name are the method ID of the data block
+containing the WMI methods. Their first parameter is a integer describing the
+instance which methods should be executed. The second parameter is an integer
+describing the WMI method ID to execute, and the third parameter is a buffer
+containing the WMI method parameters. If the data block is marked as containing
+an ASCIZ string, then this buffer should contain an ASCIZ string. The ACPI
+method will return the result of the executed WMI method.
+
+WExx ACPI methods
+-----------------
+
+Used for optionally enabling/disabling WMI events, the last two characters of
+the ACPI method are the notification ID of the data block describing the WMI
+event as hexadecimal value. Their first parameter is an integer with a value
+of 0 if the WMI event should be disabled, other values will enable
+the WMI event.
+
+WCxx ACPI methods
+-----------------
+Similar to the ``WExx`` ACPI methods, except that it controls data collection
+instead of events and thus the last two characters of the ACPI method name are
+the method ID of the data block to enable/disable.
+
+_WED ACPI method
+----------------
+
+Used to retrieve additional WMI event data, its single parameter is a integer
+holding the notification ID of the event.
diff --git a/Documentation/wmi/devices/dell-wmi-ddv.rst b/Documentation/wmi/devices/dell-wmi-ddv.rst
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+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+============================================
+Dell DDV WMI interface driver (dell-wmi-ddv)
+============================================
+
+Introduction
+============
+
+Many Dell notebooks made after ~2020 support a WMI-based interface for
+retrieving various system data like battery temperature, ePPID, diagostic data
+and fan/thermal sensor data.
+
+This interface is likely used by the `Dell Data Vault` software on Windows,
+so it was called `DDV`. Currently the ``dell-wmi-ddv`` driver supports
+version 2 and 3 of the interface, with support for new interface versions
+easily added.
+
+.. warning:: The interface is regarded as internal by Dell, so no vendor
+ documentation is available. All knowledge was thus obtained by
+ trial-and-error, please keep that in mind.
+
+Dell ePPID (electronic Piece Part Identification)
+=================================================
+
+The Dell ePPID is used to uniquely identify components in Dell machines,
+including batteries. It has a form similar to `CC-PPPPPP-MMMMM-YMD-SSSS-FFF`
+and contains the following information:
+
+* Country code of origin (CC).
+* Part number with the first character being a filling number (PPPPPP).
+* Manufacture Identification (MMMMM).
+* Manufacturing Year/Month/Date (YMD) in base 36, with Y being the last digit
+ of the year.
+* Manufacture Sequence Number (SSSS).
+* Optional Firmware Version/Revision (FFF).
+
+The `eppidtool <https://pypi.org/project/eppidtool>`_ python utility can be used
+to decode and display this information.
+
+All information regarding the Dell ePPID was gathered using Dell support
+documentation and `this website <https://telcontar.net/KBK/Dell/date_codes>`_.
+
+WMI interface description
+=========================
+
+The WMI interface description can be decoded from the embedded binary MOF (bmof)
+data using the `bmfdec <https://github.com/pali/bmfdec>`_ utility:
+
+::
+
+ [WMI, Dynamic, Provider("WmiProv"), Locale("MS\\0x409"), Description("WMI Function"), guid("{8A42EA14-4F2A-FD45-6422-0087F7A7E608}")]
+ class DDVWmiMethodFunction {
+ [key, read] string InstanceName;
+ [read] boolean Active;
+
+ [WmiMethodId(1), Implemented, read, write, Description("Return Battery Design Capacity.")] void BatteryDesignCapacity([in] uint32 arg2, [out] uint32 argr);
+ [WmiMethodId(2), Implemented, read, write, Description("Return Battery Full Charge Capacity.")] void BatteryFullChargeCapacity([in] uint32 arg2, [out] uint32 argr);
+ [WmiMethodId(3), Implemented, read, write, Description("Return Battery Manufacture Name.")] void BatteryManufactureName([in] uint32 arg2, [out] string argr);
+ [WmiMethodId(4), Implemented, read, write, Description("Return Battery Manufacture Date.")] void BatteryManufactureDate([in] uint32 arg2, [out] uint32 argr);
+ [WmiMethodId(5), Implemented, read, write, Description("Return Battery Serial Number.")] void BatterySerialNumber([in] uint32 arg2, [out] uint32 argr);
+ [WmiMethodId(6), Implemented, read, write, Description("Return Battery Chemistry Value.")] void BatteryChemistryValue([in] uint32 arg2, [out] string argr);
+ [WmiMethodId(7), Implemented, read, write, Description("Return Battery Temperature.")] void BatteryTemperature([in] uint32 arg2, [out] uint32 argr);
+ [WmiMethodId(8), Implemented, read, write, Description("Return Battery Current.")] void BatteryCurrent([in] uint32 arg2, [out] uint32 argr);
+ [WmiMethodId(9), Implemented, read, write, Description("Return Battery Voltage.")] void BatteryVoltage([in] uint32 arg2, [out] uint32 argr);
+ [WmiMethodId(10), Implemented, read, write, Description("Return Battery Manufacture Access(MA code).")] void BatteryManufactureAceess([in] uint32 arg2, [out] uint32 argr);
+ [WmiMethodId(11), Implemented, read, write, Description("Return Battery Relative State-Of-Charge.")] void BatteryRelativeStateOfCharge([in] uint32 arg2, [out] uint32 argr);
+ [WmiMethodId(12), Implemented, read, write, Description("Return Battery Cycle Count")] void BatteryCycleCount([in] uint32 arg2, [out] uint32 argr);
+ [WmiMethodId(13), Implemented, read, write, Description("Return Battery ePPID")] void BatteryePPID([in] uint32 arg2, [out] string argr);
+ [WmiMethodId(14), Implemented, read, write, Description("Return Battery Raw Analytics Start")] void BatteryeRawAnalyticsStart([in] uint32 arg2, [out] uint32 argr);
+ [WmiMethodId(15), Implemented, read, write, Description("Return Battery Raw Analytics")] void BatteryeRawAnalytics([in] uint32 arg2, [out] uint32 RawSize, [out, WmiSizeIs("RawSize") : ToInstance] uint8 RawData[]);
+ [WmiMethodId(16), Implemented, read, write, Description("Return Battery Design Voltage.")] void BatteryDesignVoltage([in] uint32 arg2, [out] uint32 argr);
+ [WmiMethodId(17), Implemented, read, write, Description("Return Battery Raw Analytics A Block")] void BatteryeRawAnalyticsABlock([in] uint32 arg2, [out] uint32 RawSize, [out, WmiSizeIs("RawSize") : ToInstance] uint8 RawData[]);
+ [WmiMethodId(18), Implemented, read, write, Description("Return Version.")] void ReturnVersion([in] uint32 arg2, [out] uint32 argr);
+ [WmiMethodId(32), Implemented, read, write, Description("Return Fan Sensor Information")] void FanSensorInformation([in] uint32 arg2, [out] uint32 RawSize, [out, WmiSizeIs("RawSize") : ToInstance] uint8 RawData[]);
+ [WmiMethodId(34), Implemented, read, write, Description("Return Thermal Sensor Information")] void ThermalSensorInformation([in] uint32 arg2, [out] uint32 RawSize, [out, WmiSizeIs("RawSize") : ToInstance] uint8 RawData[]);
+ };
+
+Each WMI method takes an ACPI buffer containing a 32-bit index as input argument,
+with the first 8 bit being used to specify the battery when using battery-related
+WMI methods. Other WMI methods may ignore this argument or interpret it
+differently. The WMI method output format varies:
+
+* if the function has only a single output, then an ACPI object
+ of the corresponding type is returned
+* if the function has multiple outputs, when an ACPI package
+ containing the outputs in the same order is returned
+
+The format of the output should be thoroughly checked, since many methods can
+return malformed data in case of an error.
+
+The data format of many battery-related methods seems to be based on the
+`Smart Battery Data Specification`, so unknown battery-related methods are
+likely to follow this standard in some way.
+
+WMI method GetBatteryDesignCapacity()
+-------------------------------------
+
+Returns the design capacity of the battery in mAh as an u16.
+
+WMI method BatteryFullCharge()
+------------------------------
+
+Returns the full charge capacity of the battery in mAh as an u16.
+
+WMI method BatteryManufactureName()
+-----------------------------------
+
+Returns the manufacture name of the battery as an ASCII string.
+
+WMI method BatteryManufactureDate()
+-----------------------------------
+
+Returns the manufacture date of the battery as an u16.
+The date is encoded in the following manner:
+
+- bits 0 to 4 contain the manufacture day.
+- bits 5 to 8 contain the manufacture month.
+- bits 9 to 15 contain the manufacture year biased by 1980.
+
+.. note::
+ The data format needs to be verified on more machines.
+
+WMI method BatterySerialNumber()
+--------------------------------
+
+Returns the serial number of the battery as an u16.
+
+WMI method BatteryChemistryValue()
+----------------------------------
+
+Returns the chemistry of the battery as an ASCII string.
+Known values are:
+
+- "Li-I" for Li-Ion
+
+WMI method BatteryTemperature()
+-------------------------------
+
+Returns the temperature of the battery in tenth degree kelvin as an u16.
+
+WMI method BatteryCurrent()
+---------------------------
+
+Returns the current flow of the battery in mA as an s16.
+Negative values indicate discharging.
+
+WMI method BatteryVoltage()
+---------------------------
+
+Returns the voltage flow of the battery in mV as an u16.
+
+WMI method BatteryManufactureAccess()
+-------------------------------------
+
+Returns a manufacture-defined value as an u16.
+
+WMI method BatteryRelativeStateOfCharge()
+-----------------------------------------
+
+Returns the capacity of the battery in percent as an u16.
+
+WMI method BatteryCycleCount()
+------------------------------
+
+Returns the cycle count of the battery as an u16.
+
+WMI method BatteryePPID()
+-------------------------
+
+Returns the ePPID of the battery as an ASCII string.
+
+WMI method BatteryeRawAnalyticsStart()
+--------------------------------------
+
+Performs an analysis of the battery and returns a status code:
+
+- ``0x0``: Success
+- ``0x1``: Interface not supported
+- ``0xfffffffe``: Error/Timeout
+
+.. note::
+ The meaning of this method is still largely unknown.
+
+WMI method BatteryeRawAnalytics()
+---------------------------------
+
+Returns a buffer usually containing 12 blocks of analytics data.
+Those blocks contain:
+
+- a block number starting with 0 (u8)
+- 31 bytes of unknown data
+
+.. note::
+ The meaning of this method is still largely unknown.
+
+WMI method BatteryDesignVoltage()
+---------------------------------
+
+Returns the design voltage of the battery in mV as an u16.
+
+WMI method BatteryeRawAnalyticsABlock()
+---------------------------------------
+
+Returns a single block of analytics data, with the second byte
+of the index being used for selecting the block number.
+
+*Supported since WMI interface version 3!*
+
+.. note::
+ The meaning of this method is still largely unknown.
+
+WMI method ReturnVersion()
+--------------------------
+
+Returns the WMI interface version as an u32.
+
+WMI method FanSensorInformation()
+---------------------------------
+
+Returns a buffer containing fan sensor entries, terminated
+with a single ``0xff``.
+Those entries contain:
+
+- fan type (u8)
+- fan speed in RPM (little endian u16)
+
+WMI method ThermalSensorInformation()
+-------------------------------------
+
+Returns a buffer containing thermal sensor entries, terminated
+with a single ``0xff``.
+Those entries contain:
+
+- thermal type (u8)
+- current temperature (s8)
+- min. temperature (s8)
+- max. temperature (s8)
+- unknown field (u8)
+
+.. note::
+ TODO: Find out what the meaning of the last byte is.
+
+ACPI battery matching algorithm
+===============================
+
+The algorithm used to match ACPI batteries to indices is based on information
+which was found inside the logging messages of the OEM software.
+
+Basically for each new ACPI battery, the serial numbers of the batteries behind
+indices 1 till 3 are compared with the serial number of the ACPI battery.
+Since the serial number of the ACPI battery can either be encoded as a normal
+integer or as a hexadecimal value, both cases need to be checked. The first
+index with a matching serial number is then selected.
+
+A serial number of 0 indicates that the corresponding index is not associated
+with an actual battery, or that the associated battery is not present.
+
+Some machines like the Dell Inspiron 3505 only support a single battery and thus
+ignore the battery index. Because of this the driver depends on the ACPI battery
+hook mechanism to discover batteries.
+
+.. note::
+ The ACPI battery matching algorithm currently used inside the driver is
+ outdated and does not match the algorithm described above. The reasons for
+ this are differences in the handling of the ToHexString() ACPI opcode between
+ Linux and Windows, which distorts the serial number of ACPI batteries on many
+ machines. Until this issue is resolved, the driver cannot use the above
+ algorithm.
+
+Reverse-Engineering the DDV WMI interface
+=========================================
+
+1. Find a supported Dell notebook, usually made after ~2020.
+2. Dump the ACPI tables and search for the WMI device (usually called "ADDV").
+3. Decode the corresponding bmof data and look at the ASL code.
+4. Try to deduce the meaning of a certain WMI method by comparing the control
+ flow with other ACPI methods (_BIX or _BIF for battery related methods
+ for example).
+5. Use the built-in UEFI diagostics to view sensor types/values for fan/thermal
+ related methods (sometimes overwriting static ACPI data fields can be used
+ to test different sensor type values, since on some machines this data is
+ not reinitialized upon a warm reset).
+
+Alternatively:
+
+1. Load the ``dell-wmi-ddv`` driver, use the ``force`` module param
+ if necessary.
+2. Use the debugfs interface to access the raw fan/thermal sensor buffer data.
+3. Compare the data with the built-in UEFI diagnostics.
+
+In case the DDV WMI interface version available on your Dell notebook is not
+supported or you are seeing unknown fan/thermal sensors, please submit a
+bugreport on `bugzilla <https://bugzilla.kernel.org>`_ so they can be added
+to the ``dell-wmi-ddv`` driver.
+
+See Documentation/admin-guide/reporting-issues.rst for further information.
diff --git a/Documentation/wmi/devices/index.rst b/Documentation/wmi/devices/index.rst
new file mode 100644
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+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+=============================
+Driver-specific Documentation
+=============================
+
+This section provides information about various devices supported by
+the Linux kernel, their protocols and driver details.
+
+.. toctree::
+ :maxdepth: 1
+ :numbered:
+ :glob:
+
+ *
+
+.. only:: subproject and html
+
+ Indices
+ =======
+
+ * :ref:`genindex`
diff --git a/Documentation/wmi/devices/wmi-bmof.rst b/Documentation/wmi/devices/wmi-bmof.rst
new file mode 100644
index 0000000000..ca1ee9a29b
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+++ b/Documentation/wmi/devices/wmi-bmof.rst
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+.. SPDX-License-Identifier: GPL-2.0-only
+
+==============================
+WMI embedded Binary MOF driver
+==============================
+
+Introduction
+============
+
+Many machines embed WMI Binary MOF (Managed Object Format) metadata used to
+describe the details of their ACPI WMI interfaces. The data can be decoded
+with tools like `bmfdec <https://github.com/pali/bmfdec>`_ to obtain a
+human readable WMI interface description, which is useful for developing
+new WMI drivers.
+
+The Binary MOF data can be retrieved from the ``bmof`` sysfs attribute of the
+associated WMI device. Please note that multiple WMI devices containing Binary
+MOF data can exist on a given system.
+
+WMI interface
+=============
+
+The Binary MOF WMI device is identified by the WMI GUID ``05901221-D566-11D1-B2F0-00A0C9062910``.
+The Binary MOF can be obtained by doing a WMI data block query. The result is
+then returned as an ACPI buffer with a variable size.
diff --git a/Documentation/wmi/index.rst b/Documentation/wmi/index.rst
new file mode 100644
index 0000000000..537cff188e
--- /dev/null
+++ b/Documentation/wmi/index.rst
@@ -0,0 +1,19 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+=============
+WMI Subsystem
+=============
+
+.. toctree::
+ :maxdepth: 1
+
+ acpi-interface
+ devices/index
+
+.. only:: subproject and html
+
+
+ Indices
+ =======
+
+ * :ref:`genindex`