Control of ethernet link-partner GPIO using OAM
An Ethernet Physical layer (PHY) device includes a PHY interface and PHY circuitry. The PHY interface is configured to connect to a physical link. The PHY circuitry is configured to generate layer-1 frames that carry data for transmission to a peer Ethernet PHY device, to insert among the layer-1 frames one or more management frames that are separate from the layer-1 frames and that are configured to control a General-Purpose Input-Output (GPIO) port associated with the peer Ethernet PHY device, to transmit the layer-1 frames and the inserted management frames, via the PHY interface, to the peer Ethernet PHY device over the physical link, for controlling one or more operations of the GPIO port associated with the peer Ethernet PHY device, and to receive, via the PHY interface, one or more verifications acknowledging that the one or more management frames were received successfully at the peer Ethernet PHY device.
1. An in-vehicle Ethernet communication system, comprising:
a first Ethernet Physical layer (PHY) device comprising (i) a first interface configured to connect to a first controller and (ii) multiple first General-Purpose Input-Output (GPIO) ports; and
a second Ethernet PHY device comprising (i) a second interface configured to connect to a second controller and (ii) multiple second GPIO ports,
the first and second Ethernet PHY devices being configured to:
transfer data between the first and second controllers by (i) communicating with the first and second controllers via the first and second interfaces and (ii) transmitting and receiving, over a physical Ethernet link between the first and second Ethernet PHY devices, layer-1 Ethernet frames that carry the data; and
transfer a multi-bit value comprising multiple bits, from a state encoder to a state decoder, using the same first and second Ethernet PHY devices and over the same physical Ethernet link used for transferring the data between the first and second controllers and independently of the first and second controllers, by:
receiving the multiple bits of the multi-bit value from the state encoder on the respective multiple first GPIO ports of the first Ethernet PHY device;
sending the multiple bits of the multi-bit value from the first Ethernet PHY device to the second Ethernet PHY device, over the physical Ethernet link, in an Ethernet Operations Administration and Maintenance (OAM) frame that is interleaved among the layer-1 Ethernet frames; and
outputting the multiple bits of the multi-bit value to the state decoder on the respective multiple second GPIO ports of the second Ethernet PHY device.
2. The in-vehicle Ethernet communication system according to claim 1 , wherein, in transferring the multi-bit value, the first and second Ethernet PHY devices are configured to indicate a safety state selected from among a plurality of safety states.
3. The in-vehicle Ethernet communication system according to claim 1 , wherein:
the state encoder is configured to encode an input so as to produce the multiple bits, and to provide the multiple bits to the multiple first GPIO ports of the first Ethernet PHY device; and
the state decoder is configured to receive the multiple bits from the multiple second GPIO ports of the second Ethernet PHY device, and to reconstruct the input from the received multiple bits.
4. The in-vehicle Ethernet communication system according to claim 1 , further comprising a safety controller, configured to enable transfer of a safety message represented by the multi-bit value, by overriding a management interface used by the first system controller to control the first Ethernet PHY device.
5. The in-vehicle Ethernet communication system according to claim 4 , wherein the safety controller is (i) separate from the first and second controllers and (ii) configured to initialize the first and second Ethernet PHY devices.
6. A method for communication in an in-vehicle Ethernet communication system that includes (i) a first Ethernet Physical layer (PHY) device comprising a first interface configured to connect to a first controller, and multiple first General-Purpose Input-Output (GPIO) ports, and (ii) a second Ethernet PHY device comprising a second interface configured to connect to a second controller, and multiple second GPIO ports, the method comprising:
transferring data between the first and second controllers by (i) communicating with the first and second controllers via the first and second interfaces and (ii) transmitting and receiving, over a physical Ethernet link between the first and second Ethernet PHY devices, layer-1 Ethernet frames that carry the data; and
transferring a multi-bit value comprising multiple bits, from a state encoder to a state decoder, using the same first and second Ethernet PHY devices and over the same physical Ethernet link used for transferring the data between the first and second controllers and independently of the first and second controllers, by:
receiving the multiple bits of the multi-bit value from the state encoder on the respective multiple first GPIO ports of the first Ethernet PHY device;
sending the multiple bits of the multi-bit value from the first Ethernet device to the second Ethernet PHY device, over the physical Ethernet link, in an Ethernet Operations Administration and Maintenance (OAM) frame that is interleaved among the layer-1 Ethernet frames; and
outputting the multiple bits of the multi-bit value to the state decoder on the respective multiple second GPIO ports of the second Ethernet PHY device.
7. The method for communication according to claim 6 , wherein transferring the multi-bit value comprises indicating a safety state selected from among a plurality of safety states.
8. The method for communication according to claim 6 , further comprising:
using the state encoder, encoding an input so as to produce the multiple bits, and providing the multiple bits to the multiple first GPIO ports of the first Ethernet PHY device; and
using the state decoder, receiving the multiple bits from the multiple second GPIO ports of the second Ethernet PHY device, and reconstructing the input from the received multiple bits.
9. The method for communication according to claim 6 , further comprising enabling transfer of a safety message represented by the multi-bit value, by overriding a management interface used by the first controller to control the first Ethernet PHY device.
10. The method for communication according to claim 9 , wherein enabling the transfer of the safety message is performed by a safety controller that is separate from the first and second controllers, and further comprising initializing the first and second Ethernet PHY devices by the safety controller.