Documentation/misc-devices/mei/mei.txt - kernel/quantenna - Git at Google

 Intel(R) Management Engine Interface (Intel(R) MEI)
 ===================================================

 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 features. The 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. The Intel MEI Driver is in charge of the
 communication channel between a host application and the Intel ME feature.

 Each Intel ME feature (Intel ME Client) is addressed by a GUID/UUID and
 each client has its own protocol. The protocol is message-based with a
 header and payload up to 512 bytes.

 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:
 http://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide


 Intel MEI Driver
 ================

 The driver exposes a misc device called /dev/mei.

 An application maintains communication with an Intel ME feature while
 /dev/mei is open. The binding to a specific feature is performed by calling
 MEI_CONNECT_CLIENT_IOCTL, which passes the desired UUID.
 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 Intel AMT Host Interface (Intel AMTHI) feature supports multiple
 simultaneous user connected applications. The Intel MEI driver
 handles this internally by maintaining request queues for the applications.

 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.

 A code snippet for an application communicating with Intel AMTHI client:

 	struct mei_connect_client_data data;
 	fd = open(MEI_DEVICE);

 	data.d.in_client_uuid = AMTHI_UUID;

 	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);


 IOCTL
 =====

 The Intel MEI Driver supports the following IOCTL commands:
 	IOCTL_MEI_CONNECT_CLIENT	Connect to firmware Feature (client).

 	usage:
 		struct mei_connect_client_data clientData;
 		ioctl(fd, IOCTL_MEI_CONNECT_CLIENT, &clientData);

 	inputs:
 		mei_connect_client_data struct contain the following
 		input field:

 		in_client_uuid -	UUID of the FW Feature that needs
 					to connect to.
 	outputs:
 		out_client_properties - Client Properties: MTU and Protocol Version.

 	error returns:
 		EINVAL	Wrong IOCTL Number
 		ENODEV	Device or Connection is not initialized or ready.
 			(e.g. Wrong UUID)
 		ENOMEM	Unable to allocate memory to client internal data.
 		EFAULT	Fatal Error (e.g. Unable to access user input data)
 		EBUSY	Connection Already Open

 	Notes:
         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_NOTIFY_SET: enable or disable event notifications

 	Usage:
 		uint32_t enable;
 		ioctl(fd, IOCTL_MEI_NOTIFY_SET, &enable);

 	Inputs:
 		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

 	Notes:
 	The client must be connected in order to enable notification events


 	IOCTL_MEI_NOTIFY_GET : retrieve event

 	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

 	Notes:
 	The client must be connected and event notification has to be enabled
 	in order to receive an event


 Intel ME 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:
 	   http://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide
 	   Under "About Intel AMT" => "Local Access"

 	   For downloading Intel LMS:
 	   http://software.intel.com/en-us/articles/download-the-latest-intel-amt-open-source-drivers/

 	   The Intel LMS opens a connection using the Intel MEI driver to the Intel LMS
 	   firmware feature using a defined UUID 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)
 	   http://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide
 	   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:
 	   http://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide
 	   Under "Setup and Configuration of Intel AMT" =>
 	   "SDK Tools Supporting Setup and Configuration" =>
 	   "Using the Local Agent Sample"

 	   An open source Intel AMT configuration utility,	implementing a local agent
 	   that accesses the Intel MEI driver, can be found here:
 	   http://software.intel.com/en-us/articles/download-the-latest-intel-amt-open-source-drivers/


 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.


 Supported Chipsets
 ==================

 7 Series Chipset Family
 6 Series Chipset Family
 5 Series Chipset Family
 4 Series Chipset Family
 Mobile 4 Series Chipset Family
 ICH9
 82946GZ/GL
 82G35 Express
 82Q963/Q965
 82P965/G965
 Mobile PM965/GM965
 Mobile GME965/GLE960
 82Q35 Express
 82G33/G31/P35/P31 Express
 82Q33 Express
 82X38/X48 Express

 ---
 linux-mei@linux.intel.com
	Intel(R) Management Engine Interface (Intel(R) MEI)
	===================================================

	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 features. The 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. The Intel MEI Driver is in charge of the
	communication channel between a host application and the Intel ME feature.

	Each Intel ME feature (Intel ME Client) is addressed by a GUID/UUID and
	each client has its own protocol. The protocol is message-based with a
	header and payload up to 512 bytes.

	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:
	http://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide


	Intel MEI Driver
	================

	The driver exposes a misc device called /dev/mei.

	An application maintains communication with an Intel ME feature while
	/dev/mei is open. The binding to a specific feature is performed by calling
	MEI_CONNECT_CLIENT_IOCTL, which passes the desired UUID.
	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 Intel AMT Host Interface (Intel AMTHI) feature supports multiple
	simultaneous user connected applications. The Intel MEI driver
	handles this internally by maintaining request queues for the applications.

	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.

	A code snippet for an application communicating with Intel AMTHI client:

	struct mei_connect_client_data data;
	fd = open(MEI_DEVICE);

	data.d.in_client_uuid = AMTHI_UUID;

	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);


	IOCTL
	=====

	The Intel MEI Driver supports the following IOCTL commands:
	IOCTL_MEI_CONNECT_CLIENT Connect to firmware Feature (client).

	usage:
	struct mei_connect_client_data clientData;
	ioctl(fd, IOCTL_MEI_CONNECT_CLIENT, &clientData);

	inputs:
	mei_connect_client_data struct contain the following
	input field:

	in_client_uuid - UUID of the FW Feature that needs
	to connect to.
	outputs:
	out_client_properties - Client Properties: MTU and Protocol Version.

	error returns:
	EINVAL Wrong IOCTL Number
	ENODEV Device or Connection is not initialized or ready.
	(e.g. Wrong UUID)
	ENOMEM Unable to allocate memory to client internal data.
	EFAULT Fatal Error (e.g. Unable to access user input data)
	EBUSY Connection Already Open

	Notes:
	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_NOTIFY_SET: enable or disable event notifications

	Usage:
	uint32_t enable;
	ioctl(fd, IOCTL_MEI_NOTIFY_SET, &enable);

	Inputs:
	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

	Notes:
	The client must be connected in order to enable notification events


	IOCTL_MEI_NOTIFY_GET : retrieve event

	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

	Notes:
	The client must be connected and event notification has to be enabled
	in order to receive an event


	Intel ME 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:
	http://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide
	Under "About Intel AMT" => "Local Access"

	For downloading Intel LMS:
	http://software.intel.com/en-us/articles/download-the-latest-intel-amt-open-source-drivers/

	The Intel LMS opens a connection using the Intel MEI driver to the Intel LMS
	firmware feature using a defined UUID 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)
	http://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide
	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:
	http://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide
	Under "Setup and Configuration of Intel AMT" =>
	"SDK Tools Supporting Setup and Configuration" =>
	"Using the Local Agent Sample"

	An open source Intel AMT configuration utility, implementing a local agent
	that accesses the Intel MEI driver, can be found here:
	http://software.intel.com/en-us/articles/download-the-latest-intel-amt-open-source-drivers/


	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.


	Supported Chipsets
	==================

	7 Series Chipset Family
	6 Series Chipset Family
	5 Series Chipset Family
	4 Series Chipset Family
	Mobile 4 Series Chipset Family
	ICH9
	82946GZ/GL
	82G35 Express
	82Q963/Q965
	82P965/G965
	Mobile PM965/GM965
	Mobile GME965/GLE960
	82Q35 Express
	82G33/G31/P35/P31 Express
	82Q33 Express
	82X38/X48 Express

	---
	linux-mei@linux.intel.com