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Diffstat (limited to 'Documentation/driver-api/mei')
| -rw-r--r-- | Documentation/driver-api/mei/hdcp.rst | 32 | ||||
| -rw-r--r-- | Documentation/driver-api/mei/iamt.rst | 101 | ||||
| -rw-r--r-- | Documentation/driver-api/mei/index.rst | 23 | ||||
| -rw-r--r-- | Documentation/driver-api/mei/mei-client-bus.rst | 168 | ||||
| -rw-r--r-- | Documentation/driver-api/mei/mei.rst | 213 | ||||
| -rw-r--r-- | Documentation/driver-api/mei/nfc.rst | 28 |
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)"]; + } |