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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 10:05:51 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 10:05:51 +0000
commit5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch)
treea94efe259b9009378be6d90eb30d2b019d95c194 /Documentation/driver-api/mei
parentInitial commit. (diff)
downloadlinux-430c2fc249ea5c0536abd21c23382884005c9093.tar.xz
linux-430c2fc249ea5c0536abd21c23382884005c9093.zip
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'Documentation/driver-api/mei')
-rw-r--r--Documentation/driver-api/mei/hdcp.rst32
-rw-r--r--Documentation/driver-api/mei/iamt.rst101
-rw-r--r--Documentation/driver-api/mei/index.rst23
-rw-r--r--Documentation/driver-api/mei/mei-client-bus.rst168
-rw-r--r--Documentation/driver-api/mei/mei.rst213
-rw-r--r--Documentation/driver-api/mei/nfc.rst28
6 files changed, 565 insertions, 0 deletions
diff --git a/Documentation/driver-api/mei/hdcp.rst b/Documentation/driver-api/mei/hdcp.rst
new file mode 100644
index 000000000..e85a065b1
--- /dev/null
+++ b/Documentation/driver-api/mei/hdcp.rst
@@ -0,0 +1,32 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+HDCP:
+=====
+
+ME FW as a security engine provides the capability for setting up
+HDCP2.2 protocol negotiation between the Intel graphics device and
+an HDC2.2 sink.
+
+ME FW prepares HDCP2.2 negotiation parameters, signs and encrypts them
+according the HDCP 2.2 spec. The Intel graphics sends the created blob
+to the HDCP2.2 sink.
+
+Similarly, the HDCP2.2 sink's response is transferred to ME FW
+for decryption and verification.
+
+Once all the steps of HDCP2.2 negotiation are completed,
+upon request ME FW will configure the port as authenticated and supply
+the HDCP encryption keys to Intel graphics hardware.
+
+
+mei_hdcp driver
+---------------
+.. kernel-doc:: drivers/misc/mei/hdcp/mei_hdcp.c
+ :doc: MEI_HDCP Client Driver
+
+mei_hdcp api
+------------
+
+.. kernel-doc:: drivers/misc/mei/hdcp/mei_hdcp.c
+ :functions:
+
diff --git a/Documentation/driver-api/mei/iamt.rst b/Documentation/driver-api/mei/iamt.rst
new file mode 100644
index 000000000..6ef3e6136
--- /dev/null
+++ b/Documentation/driver-api/mei/iamt.rst
@@ -0,0 +1,101 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Intel(R) Active Management Technology (Intel AMT)
+=================================================
+
+Prominent usage of the Intel ME Interface is to communicate with Intel(R)
+Active Management Technology (Intel AMT) implemented in firmware running on
+the Intel ME.
+
+Intel AMT provides the ability to manage a host remotely out-of-band (OOB)
+even when the operating system running on the host processor has crashed or
+is in a sleep state.
+
+Some examples of Intel AMT usage are:
+ - Monitoring hardware state and platform components
+ - Remote power off/on (useful for green computing or overnight IT
+ maintenance)
+ - OS updates
+ - Storage of useful platform information such as software assets
+ - Built-in hardware KVM
+ - Selective network isolation of Ethernet and IP protocol flows based
+ on policies set by a remote management console
+ - IDE device redirection from remote management console
+
+Intel AMT (OOB) communication is based on SOAP (deprecated
+starting with Release 6.0) over HTTP/S or WS-Management protocol over
+HTTP/S that are received from a remote management console application.
+
+For more information about Intel AMT:
+https://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide/default.htm
+
+
+Intel AMT Applications
+----------------------
+
+ 1) Intel Local Management Service (Intel LMS)
+
+ Applications running locally on the platform communicate with Intel AMT Release
+ 2.0 and later releases in the same way that network applications do via SOAP
+ over HTTP (deprecated starting with Release 6.0) or with WS-Management over
+ SOAP over HTTP. This means that some Intel AMT features can be accessed from a
+ local application using the same network interface as a remote application
+ communicating with Intel AMT over the network.
+
+ When a local application sends a message addressed to the local Intel AMT host
+ name, the Intel LMS, which listens for traffic directed to the host name,
+ intercepts the message and routes it to the Intel MEI.
+ For more information:
+ https://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide/default.htm
+ Under "About Intel AMT" => "Local Access"
+
+ For downloading Intel LMS:
+ https://github.com/intel/lms
+
+ The Intel LMS opens a connection using the Intel MEI driver to the Intel LMS
+ firmware feature using a defined GUID and then communicates with the feature
+ using a protocol called Intel AMT Port Forwarding Protocol (Intel APF protocol).
+ The protocol is used to maintain multiple sessions with Intel AMT from a
+ single application.
+
+ See the protocol specification in the Intel AMT Software Development Kit (SDK)
+ https://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide/default.htm
+ Under "SDK Resources" => "Intel(R) vPro(TM) Gateway (MPS)"
+ => "Information for Intel(R) vPro(TM) Gateway Developers"
+ => "Description of the Intel AMT Port Forwarding (APF) Protocol"
+
+ 2) Intel AMT Remote configuration using a Local Agent
+
+ A Local Agent enables IT personnel to configure Intel AMT out-of-the-box
+ without requiring installing additional data to enable setup. The remote
+ configuration process may involve an ISV-developed remote configuration
+ agent that runs on the host.
+ For more information:
+ https://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide/default.htm
+ Under "Setup and Configuration of Intel AMT" =>
+ "SDK Tools Supporting Setup and Configuration" =>
+ "Using the Local Agent Sample"
+
+Intel AMT OS Health Watchdog
+----------------------------
+
+The Intel AMT Watchdog is an OS Health (Hang/Crash) watchdog.
+Whenever the OS hangs or crashes, Intel AMT will send an event
+to any subscriber to this event. This mechanism means that
+IT knows when a platform crashes even when there is a hard failure on the host.
+
+The Intel AMT Watchdog is composed of two parts:
+ 1) Firmware feature - receives the heartbeats
+ and sends an event when the heartbeats stop.
+ 2) Intel MEI iAMT watchdog driver - connects to the watchdog feature,
+ configures the watchdog and sends the heartbeats.
+
+The Intel iAMT watchdog MEI driver uses the kernel watchdog API to configure
+the Intel AMT Watchdog and to send heartbeats to it. The default timeout of the
+watchdog is 120 seconds.
+
+If the Intel AMT is not enabled in the firmware then the watchdog client won't enumerate
+on the me client bus and watchdog devices won't be exposed.
+
+---
+linux-mei@linux.intel.com
diff --git a/Documentation/driver-api/mei/index.rst b/Documentation/driver-api/mei/index.rst
new file mode 100644
index 000000000..3a22b522e
--- /dev/null
+++ b/Documentation/driver-api/mei/index.rst
@@ -0,0 +1,23 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+.. include:: <isonum.txt>
+
+===================================================
+Intel(R) Management Engine Interface (Intel(R) MEI)
+===================================================
+
+**Copyright** |copy| 2019 Intel Corporation
+
+
+.. only:: html
+
+ .. class:: toc-title
+
+ Table of Contents
+
+.. toctree::
+ :maxdepth: 3
+
+ mei
+ mei-client-bus
+ iamt
diff --git a/Documentation/driver-api/mei/mei-client-bus.rst b/Documentation/driver-api/mei/mei-client-bus.rst
new file mode 100644
index 000000000..f242b3f8d
--- /dev/null
+++ b/Documentation/driver-api/mei/mei-client-bus.rst
@@ -0,0 +1,168 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+==============================================
+Intel(R) Management Engine (ME) Client bus API
+==============================================
+
+
+Rationale
+=========
+
+The MEI character device is useful for dedicated applications to send and receive
+data to the many FW appliance found in Intel's ME from the user space.
+However, for some of the ME functionalities it makes sense to leverage existing software
+stack and expose them through existing kernel subsystems.
+
+In order to plug seamlessly into the kernel device driver model we add kernel virtual
+bus abstraction on top of the MEI driver. This allows implementing Linux kernel drivers
+for the various MEI features as a stand alone entities found in their respective subsystem.
+Existing device drivers can even potentially be re-used by adding an MEI CL bus layer to
+the existing code.
+
+
+MEI CL bus API
+==============
+
+A driver implementation for an MEI Client is very similar to any other existing bus
+based device drivers. The driver registers itself as an MEI CL bus driver through
+the ``struct mei_cl_driver`` structure defined in :file:`include/linux/mei_cl_bus.c`
+
+.. code-block:: C
+
+ struct mei_cl_driver {
+ struct device_driver driver;
+ const char *name;
+
+ const struct mei_cl_device_id *id_table;
+
+ int (*probe)(struct mei_cl_device *dev, const struct mei_cl_id *id);
+ int (*remove)(struct mei_cl_device *dev);
+ };
+
+
+
+The mei_cl_device_id structure defined in :file:`include/linux/mod_devicetable.h` allows a
+driver to bind itself against a device name.
+
+.. code-block:: C
+
+ struct mei_cl_device_id {
+ char name[MEI_CL_NAME_SIZE];
+ uuid_le uuid;
+ __u8 version;
+ kernel_ulong_t driver_info;
+ };
+
+To actually register a driver on the ME Client bus one must call the :c:func:`mei_cl_add_driver`
+API. This is typically called at module initialization time.
+
+Once the driver is registered and bound to the device, a driver will typically
+try to do some I/O on this bus and this should be done through the :c:func:`mei_cl_send`
+and :c:func:`mei_cl_recv` functions. More detailed information is in :ref:`api` section.
+
+In order for a driver to be notified about pending traffic or event, the driver
+should register a callback via :c:func:`mei_cl_devev_register_rx_cb` and
+:c:func:`mei_cldev_register_notify_cb` function respectively.
+
+.. _api:
+
+API:
+----
+.. kernel-doc:: drivers/misc/mei/bus.c
+ :export: drivers/misc/mei/bus.c
+
+
+
+Example
+=======
+
+As a theoretical example let's pretend the ME comes with a "contact" NFC IP.
+The driver init and exit routines for this device would look like:
+
+.. code-block:: C
+
+ #define CONTACT_DRIVER_NAME "contact"
+
+ static struct mei_cl_device_id contact_mei_cl_tbl[] = {
+ { CONTACT_DRIVER_NAME, },
+
+ /* required last entry */
+ { }
+ };
+ MODULE_DEVICE_TABLE(mei_cl, contact_mei_cl_tbl);
+
+ static struct mei_cl_driver contact_driver = {
+ .id_table = contact_mei_tbl,
+ .name = CONTACT_DRIVER_NAME,
+
+ .probe = contact_probe,
+ .remove = contact_remove,
+ };
+
+ static int contact_init(void)
+ {
+ int r;
+
+ r = mei_cl_driver_register(&contact_driver);
+ if (r) {
+ pr_err(CONTACT_DRIVER_NAME ": driver registration failed\n");
+ return r;
+ }
+
+ return 0;
+ }
+
+ static void __exit contact_exit(void)
+ {
+ mei_cl_driver_unregister(&contact_driver);
+ }
+
+ module_init(contact_init);
+ module_exit(contact_exit);
+
+And the driver's simplified probe routine would look like that:
+
+.. code-block:: C
+
+ int contact_probe(struct mei_cl_device *dev, struct mei_cl_device_id *id)
+ {
+ [...]
+ mei_cldev_enable(dev);
+
+ mei_cldev_register_rx_cb(dev, contact_rx_cb);
+
+ return 0;
+ }
+
+In the probe routine the driver first enable the MEI device and then registers
+an rx handler which is as close as it can get to registering a threaded IRQ handler.
+The handler implementation will typically call :c:func:`mei_cldev_recv` and then
+process received data.
+
+.. code-block:: C
+
+ #define MAX_PAYLOAD 128
+ #define HDR_SIZE 4
+ static void conntact_rx_cb(struct mei_cl_device *cldev)
+ {
+ struct contact *c = mei_cldev_get_drvdata(cldev);
+ unsigned char payload[MAX_PAYLOAD];
+ ssize_t payload_sz;
+
+ payload_sz = mei_cldev_recv(cldev, payload, MAX_PAYLOAD)
+ if (reply_size < HDR_SIZE) {
+ return;
+ }
+
+ c->process_rx(payload);
+
+ }
+
+MEI Client Bus Drivers
+======================
+
+.. toctree::
+ :maxdepth: 2
+
+ hdcp
+ nfc
diff --git a/Documentation/driver-api/mei/mei.rst b/Documentation/driver-api/mei/mei.rst
new file mode 100644
index 000000000..4f2ced4cc
--- /dev/null
+++ b/Documentation/driver-api/mei/mei.rst
@@ -0,0 +1,213 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Introduction
+============
+
+The Intel Management Engine (Intel ME) is an isolated and protected computing
+resource (Co-processor) residing inside certain Intel chipsets. The Intel ME
+provides support for computer/IT management and security features.
+The actual feature set depends on the Intel chipset SKU.
+
+The Intel Management Engine Interface (Intel MEI, previously known as HECI)
+is the interface between the Host and Intel ME. This interface is exposed
+to the host as a PCI device, actually multiple PCI devices might be exposed.
+The Intel MEI Driver is in charge of the communication channel between
+a host application and the Intel ME features.
+
+Each Intel ME feature, or Intel ME Client is addressed by a unique GUID and
+each client has its own protocol. The protocol is message-based with a
+header and payload up to maximal number of bytes advertised by the client,
+upon connection.
+
+Intel MEI Driver
+================
+
+The driver exposes a character device with device nodes /dev/meiX.
+
+An application maintains communication with an Intel ME feature while
+/dev/meiX is open. The binding to a specific feature is performed by calling
+:c:macro:`MEI_CONNECT_CLIENT_IOCTL`, which passes the desired GUID.
+The number of instances of an Intel ME feature that can be opened
+at the same time depends on the Intel ME feature, but most of the
+features allow only a single instance.
+
+The driver is transparent to data that are passed between firmware feature
+and host application.
+
+Because some of the Intel ME features can change the system
+configuration, the driver by default allows only a privileged
+user to access it.
+
+The session is terminated calling :c:expr:`close(fd)`.
+
+A code snippet for an application communicating with Intel AMTHI client:
+
+In order to support virtualization or sandboxing a trusted supervisor
+can use :c:macro:`MEI_CONNECT_CLIENT_IOCTL_VTAG` to create
+virtual channels with an Intel ME feature. Not all features support
+virtual channels such client with answer EOPNOTSUPP.
+
+.. code-block:: C
+
+ struct mei_connect_client_data data;
+ fd = open(MEI_DEVICE);
+
+ data.d.in_client_uuid = AMTHI_GUID;
+
+ ioctl(fd, IOCTL_MEI_CONNECT_CLIENT, &data);
+
+ printf("Ver=%d, MaxLen=%ld\n",
+ data.d.in_client_uuid.protocol_version,
+ data.d.in_client_uuid.max_msg_length);
+
+ [...]
+
+ write(fd, amthi_req_data, amthi_req_data_len);
+
+ [...]
+
+ read(fd, &amthi_res_data, amthi_res_data_len);
+
+ [...]
+ close(fd);
+
+
+User space API
+
+IOCTLs:
+=======
+
+The Intel MEI Driver supports the following IOCTL commands:
+
+IOCTL_MEI_CONNECT_CLIENT
+-------------------------
+Connect to firmware Feature/Client.
+
+.. code-block:: none
+
+ Usage:
+
+ struct mei_connect_client_data client_data;
+
+ ioctl(fd, IOCTL_MEI_CONNECT_CLIENT, &client_data);
+
+ Inputs:
+
+ struct mei_connect_client_data - contain the following
+ Input field:
+
+ in_client_uuid - GUID of the FW Feature that needs
+ to connect to.
+ Outputs:
+ out_client_properties - Client Properties: MTU and Protocol Version.
+
+ Error returns:
+
+ ENOTTY No such client (i.e. wrong GUID) or connection is not allowed.
+ EINVAL Wrong IOCTL Number
+ ENODEV Device or Connection is not initialized or ready.
+ ENOMEM Unable to allocate memory to client internal data.
+ EFAULT Fatal Error (e.g. Unable to access user input data)
+ EBUSY Connection Already Open
+
+:Note:
+ max_msg_length (MTU) in client properties describes the maximum
+ data that can be sent or received. (e.g. if MTU=2K, can send
+ requests up to bytes 2k and received responses up to 2k bytes).
+
+IOCTL_MEI_CONNECT_CLIENT_VTAG:
+------------------------------
+
+.. code-block:: none
+
+ Usage:
+
+ struct mei_connect_client_data_vtag client_data_vtag;
+
+ ioctl(fd, IOCTL_MEI_CONNECT_CLIENT_VTAG, &client_data_vtag);
+
+ Inputs:
+
+ struct mei_connect_client_data_vtag - contain the following
+ Input field:
+
+ in_client_uuid - GUID of the FW Feature that needs
+ to connect to.
+ vtag - virtual tag [1, 255]
+
+ Outputs:
+ out_client_properties - Client Properties: MTU and Protocol Version.
+
+ Error returns:
+
+ ENOTTY No such client (i.e. wrong GUID) or connection is not allowed.
+ EINVAL Wrong IOCTL Number or tag == 0
+ ENODEV Device or Connection is not initialized or ready.
+ ENOMEM Unable to allocate memory to client internal data.
+ EFAULT Fatal Error (e.g. Unable to access user input data)
+ EBUSY Connection Already Open
+ EOPNOTSUPP Vtag is not supported
+
+IOCTL_MEI_NOTIFY_SET
+---------------------
+Enable or disable event notifications.
+
+
+.. code-block:: none
+
+ Usage:
+
+ uint32_t enable;
+
+ ioctl(fd, IOCTL_MEI_NOTIFY_SET, &enable);
+
+
+ uint32_t enable = 1;
+ or
+ uint32_t enable[disable] = 0;
+
+ Error returns:
+
+
+ EINVAL Wrong IOCTL Number
+ ENODEV Device is not initialized or the client not connected
+ ENOMEM Unable to allocate memory to client internal data.
+ EFAULT Fatal Error (e.g. Unable to access user input data)
+ EOPNOTSUPP if the device doesn't support the feature
+
+:Note:
+ The client must be connected in order to enable notification events
+
+
+IOCTL_MEI_NOTIFY_GET
+--------------------
+Retrieve event
+
+.. code-block:: none
+
+ Usage:
+ uint32_t event;
+ ioctl(fd, IOCTL_MEI_NOTIFY_GET, &event);
+
+ Outputs:
+ 1 - if an event is pending
+ 0 - if there is no even pending
+
+ Error returns:
+ EINVAL Wrong IOCTL Number
+ ENODEV Device is not initialized or the client not connected
+ ENOMEM Unable to allocate memory to client internal data.
+ EFAULT Fatal Error (e.g. Unable to access user input data)
+ EOPNOTSUPP if the device doesn't support the feature
+
+:Note:
+ The client must be connected and event notification has to be enabled
+ in order to receive an event
+
+
+
+Supported Chipsets
+==================
+82X38/X48 Express and newer
+
+linux-mei@linux.intel.com
diff --git a/Documentation/driver-api/mei/nfc.rst b/Documentation/driver-api/mei/nfc.rst
new file mode 100644
index 000000000..b5b6fc96f
--- /dev/null
+++ b/Documentation/driver-api/mei/nfc.rst
@@ -0,0 +1,28 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+MEI NFC
+-------
+
+Some Intel 8 and 9 Serieses chipsets supports NFC devices connected behind
+the Intel Management Engine controller.
+MEI client bus exposes the NFC chips as NFC phy devices and enables
+binding with Microread and NXP PN544 NFC device driver from the Linux NFC
+subsystem.
+
+.. kernel-render:: DOT
+ :alt: MEI NFC digraph
+ :caption: **MEI NFC** Stack
+
+ digraph NFC {
+ cl_nfc -> me_cl_nfc;
+ "drivers/nfc/mei_phy" -> cl_nfc [lhead=bus];
+ "drivers/nfc/microread/mei" -> cl_nfc;
+ "drivers/nfc/microread/mei" -> "drivers/nfc/mei_phy";
+ "drivers/nfc/pn544/mei" -> cl_nfc;
+ "drivers/nfc/pn544/mei" -> "drivers/nfc/mei_phy";
+ "net/nfc" -> "drivers/nfc/microread/mei";
+ "net/nfc" -> "drivers/nfc/pn544/mei";
+ "neard" -> "net/nfc";
+ cl_nfc [label="mei/bus(nfc)"];
+ me_cl_nfc [label="me fw (nfc)"];
+ }