Method, apparatus, and system for propagating PCIe hot reset across a non-transparent bridge on a PCIe add-in card

A method performed at a system management controller of an add-in card compliant with a peripheral component interconnect express (PCIe) protocol, the method comprising:

• monitoring a register bit value of a non-transparent bridge residing on the add-in card;
• determining that the register bit value is different than an expected value;
• and
• signaling a warm reset to a processor on the add-in card.

A system management controller (SMC) residing on an add-in card compliant with a peripheral component interconnect express (PCIe) protocol, the SMC comprising one or more non-transitory computer-readable media comprising instructions to cause an apparatus, upon execution of the instructions by one or more processors of the apparatus, to:

• poll a register value on a non-transparent bridge (NTB);
• determine that the register value is incorrect;
• and
• trigger a warm reset of the processor.

A system comprising:

• an add-in card comprising:
• non-transparent bridge (NTB) residing on an add-in card compliant with a peripheral component interconnect express (PCIe) protocol;
• a system management controller (SMC) residing on the add-in card and in communication with the NTB;
• and
• a peripheral component residing on the add-in card;
• and
• a host device coupled to the add-in card by an edge connector and in communication with the add-in card by a link compliant with the PCIe protocol;
• the host device to:
• transmit an in-band hot reset message to the add-in card across the link;
• the NTB to:
• receive the in-band hot reset message from a host device from across a link compliant with the PCIe protocol;
• and
• reset a NTB configuration register value based on receiving the in-band hot reset message;
• the SMC to:
• monitor the NTB configuration register value;
• determine that the NTB configuration register value is incorrect;
• and
• transmit a warm reset signal to the peripheral component.