Method and system for watermarking a USB PD protocol hardware sub-system
A system for watermarking a USB Type-C and PD protocol hardware sub-system existing as a part of a SOC/IC system includes a tester to generate a watermarking signal, a device under test (DUT), wherein the DUT is configured with a USB Type-C port with power delivery implementation and including a hardware subsystem configured for watermarking the DUT and transmit a response signal upon receipt of the watermarking signal from the tester. The tester includes a controller including one or more processors that execute a set of executable instructions that are stored in a memory, upon which execution, the processor causes the controller to generate the watermarking signal, the watermarking signal comprises a custom signal and a custom packet associated with a configured custom signal stored in a data buffer that is associated with the SOC/IC system, and transmit the watermarking signal on one or more configuration channel (CC) lines.
1 . A hardware subsystem operatively coupled to a device under test (DUT), said hardware subsystem comprising:
a watermarking signal detection circuit comprising a multiplexer structure, a look-up table storing key-value pairs mapping combinations of K-codes to predefined packets, and control logic, wherein the watermarking signal detection circuit is configured to:
detect a watermarking signal transmitted by a tester on a configuration channel (CC) lines coupled to a Type-C port of a Universal Serial Bus (USB) Type-C and Power Delivery (PD) protocol associated with the hardware subsystem, said tester configured to test whether the DUT is watermarked or not, wherein the watermarking signal comprises a custom signaling comprising a combination of K-Codes, other than Start of Packet (SOP) ordered sets defined in the USB Power Delivery Specification;
automatically assume control via the multiplexer structure to enable direct communication between the watermarking signal detection circuit and a USB Type-C and PD stack and a bus interface, bypassing a System on Chip/Integrated Circuit (SOC/IC) microcontroller associated with the hardware subsystem;
respond with a response signal, said response signal comprising a pre-defined packet having a vendor identity and a secret code corresponding to the combination of K-codes received;
wherein the watermarking signal comprises the combination of K-codes;
transmit the response signal through a buffer in an existing USB Type-C and PD stack, wherein the response signal is fetched through a key-value mechanism comprising a unique code corresponding to the combination of K-codes in the watermarking signal; and
relinquishes control via the multiplexer structure to restore communication between the microcontroller (MCU) and the bus interface and the USB Type-C and PD stack, the microcontroller (MCU) operatively coupled to the DUT once a transmission of the response signal is complete.