Introduction¶

Xilinx® Alveo™ Data Center cards use the following two communication channels for management.

Out-of-band communication channel: The satellite controller communicates with the server baseboard management controller (BMC) via SMBus/I2C interface to provide out-of-band card management functionalities.

In-band communication channel: The PCIe interface provides in-band management to host for card programming and communication of sensor information, such as power and temperature. The host CPU communicates across PCIe to the card management controller (CMC) residing on the FPGA, which has a connection to the satellite controller. The CMC firmware (running in MicroBlaze™ on the FPGA) and the satellite controller firmware (running in MSP432 MCU) communicates via the UART channel using a Xilinx proprietary protocol. All sensor information are passed from the satellite controller to the host through this in-band channel.

Satellite Controller (SC)¶

The satellite controller firmware runs on TI’s MSP432 device and is an essential component of Alveo card management, providing in-band and OoB communication mechanisms. The MSP432 MCU, EEPROM and few select peripherals reside on the auxiliary power domain (i.e.) 3V3_AUX.

Figure: Alveo communication path block diagram

Figure: Alveo U30 specific block diagram

Satellite Controller Firmware Version

Not all features described in this document are available in older SC FW. Refer to Alveo Data Center Accelerator Card Platforms User Guide (UG1120) to ensure the latest FW is being used.

Out-of-Band Communication¶

When installed in a server, the SC FW communicates with server BMC. The main purpose of OoB communication is to respond to requests that originate from server BMC. It uses this information to take action related to power and thermal management (i.e., to ramp-up fans or send requests to throttle down power consumption). The MSP432 and the sensors and peripherals it accesses reside on the AUX 3.3V always-on power domain.

The SMBus/I2C is used for OoB communication. The OoB communication supports three protocols. The protocols and the I2C slave address (both 7-bit and 8-bit) are given in the following table.

Table: Slave Addresses and Corresponding Protocols

I2C Slave Address (7-bit)	I2C Slave Address (8-bit)	Protocol/Features Supported
0x18	0x30	Standard PLDM/MCTP
0x50	0xA0	IPMI FRU data
0x61	0xC2	Default SMBus (2.0) for ARP
0x65	0xCA	Standard I2C commands

IPMI FRU support

SC FW supports IPMI field replaceable unit (FRU) data read at I2C slave address 0x50 (0xA0 in 8-bit). For FRU data access, 2-byte addressing mode is supported and the FRU data contents are explained in (Alveo FRU Data Specification).

See Alveo™ FRU Support for more details.

Standard I2C/SMBus Communication

SC FW supports I2C/SMBus protocol based OoB communication at I2C slave address 0x65 (0xCA in 8-bit) and provides support for server BMC that does not accept PLDM or distributed management task force (DMTF) specifications. The following information is exposed via I2C/ SMBus protocol:

Thermal sensors such as FPGA, max Board, max DIMM, and max QSFP temperature
Total board power consumption
SC FW version number
Critical Sensor Data Record (CSDR)

See I2C/SMBus Commands I2C command implementation details.

The following table is a comprehensive list of all OoB commands supported by SC using Standard I2C/SMBus protocols.

Table: List of standard I2C/SMBus commands

Command Code	Sensor Name	SMBus Transaction Type	Num of resp Bytes
01h	Max DIMM temperature	Read bytes	1
02h	Max Board temperature	Read bytes	1
03h	Board power consumption	Read words	2
04h	SC FW version	Read bytes	4
05h	FPGA die temperature	Read bytes	1
06h	Max QSFP temperature	Read bytes	1
0Fh	Reset FPGA	Write byte	1
20h	CSDR	Block read	64

PLDM Over MCTP Over SMBus Protocol

SC supports the SMBus discovery via the default SMBus 2.0 at I2C slave address 0x61 (0xC2 in 8-bit) and the MCTP/PLDM protocol at I2C slave address 0x18 (0x30 in 8-bit). Alveo OoB implementation adheres to the following DMTF specifications:

PLDM Base Specification ([DSP0240])
PLDM for Platform Monitoring and Control Specification ([DSP0248])
MCTP Base Specification ([DSP0236])
MCTP SMBus Binding Spec ([DSP0237])

See DMTF Implementation for more details

The following figure illustrates the PLDM over MCTP over SMBus binding specification stack.

Figure: PLDM Over MCTP Over SMBus Binding Specification Stack

The following sensor readings are reported via PLDM OoB:

FPGA die/junction temperature

Board temperature

QSFP0 temperature

QSFP1 temperature

Default SMBus 2.0 commands

For the purposes of SMBus address discovery (at default SMBus address 0xC2 (8-bit)), Alveo cards are ‘Fixed and Non-Discoverable Device’. Only Get UDID (general) and Get UDID (directed) commands are supported.

MCTP control messages The following MCTP control commands are supported in the SC:

Table: Supported MCTP control commands and description

Command	ID	Description
Set Endpoint ID	0x01	Assigns an EID to the endpoint at the given physical address
Get Endpoint ID	0x02	Returns the EID presently assigned to an endpoint
Get Endpoint UUID	0x03	Retrieves a per-device unique UUID associated with the endpoint
Get MCTP Version Support	0x04	Lists which versions of the MCTP control protocol are supported on an endpoint
Get Message Type Support	0x05	Lists the message types that an endpoint supports

PLDM commands

The following PLDM commands are supported in the SC:

Table: Supported PLDM commands and description

Command	ID	Description
SetTID	0x01	Sets the terminus ID (TID) for a PLDM terminus
GetTID	0x02	Returns the present TID setting for a PLDM terminus
GetPLDMVersion	0x03	Returns versions for PLDM base & type specification
GetPLDMTypes	0x04	Returns PLDM type capabilities and list of the supported PLDM types
GetPLDMCommands	0x05	Returns PLDM command capabilities supported for a specific PLDM type and version
GetSensorReading	0x11	Returns present reading and threshold event state values from a numeric sensor
GetSensorThresholds	0x12	Returns the present threshold settings for a PLDM numeric sensor
GetPDRRepositoryInfo	0x50	Returns size & number of records in PDR and time stamps on last PRD update
GetPDR	0x51	Returns individual PDRs from a PDR repository
GetPDRRepoSignature	0x53	Returns a signature that changes when the PDR repo has been changed

These PLDM commands are categorized into type 0 and type 2, as detailed in the following table.

Table: Supported Type 0 and Type 2 PLDM commands

PLDM Type 0 Commands	PLDM Type 2 Commands
SetTID (0x01)	SetTID (0x01)
GetTID (0x02)	GetTID (0x02)
GetPLDMVersion (0x03)	GetSensorReading (0x11)
GetPLDMTypes (0x04)	GetSensorThresholds (0x12)
GetPLDMCommands (0x05)	GetPDRRepositoryInfo (0x50)

Xilinx Support

For support resources such as answers, documentation, downloads, and forums, see the Alveo Accelerator Cards Xilinx Community Forum.

License

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