Verifying runtime switch-over between multiple I/O protocols on shared I/O connection
A verification environment enables verification of runtime switch-over—i.e., a switch-over without restarting the device under test—between multiple I/O protocols that share a same physical interface. The device under test can be a switch unit having multiple logical protocol processing units and a logical protocol multiplexor. The verification environment includes a switch-over detector which monitors the state of the device under test, and a switch-over controller that controls the switch-over sequence by pausing and re-starting traffic on all or specific protocol drivers of the verification environment.
1. A method for verifying a switch unit, the method comprising:
detecting a runtime switch-over of a switch unit from communicating on a port according to a first protocol to communicating according to a second protocol;
quiescing traffic of the first protocol from a first protocol driver through the switch unit;
starting test traffic of the second protocol from a second protocol driver through the switch unit, wherein the second protocol driver is external to the switch unit and generates the test traffic for verifying that the switch unit operates in conformity with the second protocol; and
verifying operation of the switch unit in response to the test traffic of the second protocol from the second protocol driver based on compliance with the second protocol,
wherein the switch unit comprises a logical protocol multiplexor, a first logical protocol processing unit associated with the first protocol, and a second logical protocol processing unit associated with the second protocol, and
wherein communications according to the first protocol and communications according to the second protocol share a same interface of the switch unit.
2. The method of claim 1 , wherein prior to the starting the test traffic of the second protocol from the second protocol driver through the switch unit, the method further comprises:
initiating a protocol-specific sequence associated with the second protocol.
3. The method of claim 1 , further comprising:
responsive to detecting the runtime switch-over of the switch unit, modifying operation of a protocol processing unit driver communicatively coupled to the switch unit.
4. The method of claim 1 , wherein quiescing the traffic of the first protocol from the first protocol driver through the switch unit further comprises:
invoking an application protocol interface (API) of the first protocol driver to quiesce the traffic of the first protocol.
5. The method of claim 1 , wherein starting the test traffic of the second protocol from the second protocol driver through the switch unit further comprises:
invoking an application protocol interface (API) of the second protocol driver to restart the test traffic of the second protocol.
6. The method claim 1 , wherein the first protocol and the second protocol are I/O communications protocols selected from the group consisting of: Peripheral Component Interconnect Express (PCIe), Serial ATA (SATA), and Universal Serial Bus (USB).
7. The method of claim 1 ,
wherein the runtime switch-over of the switch unit is detected based on monitoring of a logical state of the switch unit maintained in a register or data structure, and
wherein verifying operation of the switch unit in response to the test traffic from the second protocol driver includes at least one of comparing internal states of one or more logical processing units of the switch unit to expected results according to a specification of the second protocol or determining whether output from the one or more logical protocol processing units in response to the test traffic from the second protocol driver complies with the second protocol.