Programmable link training sequences

A non-transitory machine readable storage medium that stores instructions to, when executed by a machine, cause the machine to:

• based on a result of a first phase of multiple phases of a link training of a serial communication link with an endpoint device, identify a first training set sequence and a second training set sequence to be communicated in a second phase of the multiple phases;
• selecting a first state machine and a second state machine;
• programming the first state machine to communicate the first training set sequence to the serial communication link and the second state machine to communicate the second training set sequence to the serial communication link;
• register the first state machine and the second state machine with an arbiter to activate the first state machine and the second state machine;
• and
• programming the arbiter to arbitrate access between the first and second state machines and the serial communication link.

An apparatus comprising:

• a physical interface comprising a transceiver to communicate data with a serial communication link;
• a training set generator coupled to the physical interface to generate a first training set sequence to be communicated by the transceiver to the serial communication link during link training of the serial communication link, wherein the training set generator comprises a first plurality of state machines associated with transmitting data to the serial communication link, and the state machine is associated with registers;
• a training set decoder coupled to the physical interface to receive a second training set sequence from the serial communication link during link training of the serial communication link, wherein the training set decoder comprises a second plurality of state machines associated with receiving data from the serial communication link;
• and
• a processor to:
• based on a result of a first phase of multiple phases of a link training of the serial communication link, identify a first training set sequence to be communicated to the serial communication link and a second training set sequence to be received from the serial communication link as part of the link training;
• select a first state machine of the first plurality of state machines;
• select a second state machine of the second plurality of state machines:
• program the first state machine to communicate the first training set sequence to the serial communication link, wherein programming the first state machine comprises programming the first state machine with a data pattern associated with the first training set sequence and programming the first state machine with a condition to regulate a number of times that the state machine communicates the data pattern to the serial communication link;
• program the second state machine to receive the second training set sequence from the serial communication link, wherein programming the second state machine comprises programming the second state machine with a packet header associated with the second training set sequence;
• and
• reprogram the registers with data representing another training set to be generated by the first state machine during a second phase of the multiple phase process to train the serial communication link.

A method comprising:

• in response to feedback received from ongoing link training with an endpoint device over a serial communication link, a processor identifying a first training set sequence to be communicated to the serial communication link and identifying a second training set sequence to be received from the serial communication link as part of the ongoing link training;
• the processor selecting a first state machine of a first plurality of state machines associated with transmitting data to the serial communication link;
• the processor selecting a second state machine of a second plurality of state machines associated with receiving data from the serial communication link;
• the processor programming the selected first state machine to communicate the first training set sequence to the serial communication link, wherein programming the first state machine comprises programming the first state machine with a data pattern associated with the first training set sequence and programming the first state machine with a condition to regulate a number of times that the state machine communicates the data pattern to the serial communication link;
• and
• the processor programming the selected second state machine to receive the second training set sequence from the serial communication link, wherein programming the second state machine comprises programming the second state machine with a packet header associated with the second training set sequence.