Changing accelerator card images without host system reboot

1. A method, comprising:

receiving, within an integrated circuit of an accelerator card, an address of a platform image stored in a non-volatile memory of the accelerator card;

wherein the address is received over a communication link between a host system and the accelerator card while the communication link is connected, and the platform image specifies, at least in part, platform circuitry for implementation in the integrated circuit;

detecting, within a register of the integrated circuit, that a warm boot enable flag is set and that the communication link with the host system is disconnected; and

in response to detecting that the warm boot enable flag is set and that the communication link is disconnected, initiating loading of the platform image from the address of the non-volatile memory into the integrated circuit.

2. The method of claim 1 , wherein the loading the platform image into the integrated circuit implements the platform circuitry within the integrated circuit.

3. The method of claim 1 , wherein the warm boot enable flag is set by the host system via the communication link while connected.

4. The method of claim 1 , wherein the loading the platform image from the non-volatile memory into the integrated circuit is performed while the communication link is disconnected.

5. The method of claim 1 , further comprising:

the host system connecting the communication link after a predetermined amount of time.

6. The method of claim 5 , wherein the host system remains operational throughout the communication link being disconnected and connected after the predetermined amount of time.

7. The method of claim 1 , wherein the communication link is a Peripheral Component Interconnect Express (PCIe) communication link.

8. A system, comprising:

an accelerator card having a non-volatile memory and an integrated circuit, wherein the integrated circuit includes:

a communication interface configured to communicate over a communication link;

a warm boot controller coupled to the communication interface;

an internal configuration access port coupled to the warm boot controller;

a memory controller coupled to the internal configuration access port, wherein the memory controller is configured to communicate with the non-volatile memory; and

wherein the warm boot controller is configured to instruct the internal configuration access port to load a platform image from the non-volatile memory into the integrated circuit via the memory controller in response to determining that a warm boot enable flag is set and the communication link is disconnected.

9. The system of claim 8 , wherein the platform image specifies, at least in part, platform circuitry for the integrated circuit and loading the platform image into the integrated circuit implements the platform circuitry within the integrated circuit.

10. The system of claim 8 , wherein the communication link is a Peripheral Component Interconnect Express (PCIe) communication link.

11. The system of claim 8 , wherein the platform image is loaded into the integrated circuit while the communication link is disconnected.

12. The system of claim 8 , wherein the warm boot controller includes:

a register space that is writable by a host system over the communication link;

a control circuit configured to detect that a warm boot enable flag within the register space is set by the host system; and

a link monitor configured to monitor the communication link to determine a status of the communication link and indicate the status to the control circuit in response to detecting that the communication link is disconnected.

13. The system of claim 12 , wherein the control circuit is configured to initiate loading of the platform image in response to determining that the warm boot enable flag of the register space is set and that the communication link is disconnected.

14. The system of claim 13 , wherein the register space is configured to receive an address of the platform image from the host system over the communication link.

15. The system of claim 14 , wherein the warm boot controller includes:

a command sequencer configured to provide the address to the internal configuration access port and instruct the internal configuration access port to begin loading the platform image.

16. The system of claim 8 , wherein the integrated circuit is coupled to a host system via the communication link, wherein the host system is configured to set the warm boot enable flag in the integrated circuit and, in response to setting the warm boot enable flag, disconnect the communication link.

17. The system of claim 16 , wherein the host system is configured to disconnect the communication link by:

unloading software drivers of the host system for communicating with the accelerator card via the communication link;

removing an upstream port of the communication link; and

adjusting a bit in a link control register offset that disables the communication link.

18. The system of claim 16 , wherein the host system is configured to connect the communication link after a predetermined amount of time.

19. The system of claim 18 , wherein the host system is configured to connect the communication link by:

adjusting a bit in a link control register offset that enables the communication link;

rescan the communication interface; and

load software drivers of the host system for communicating with the accelerator card via the communication link.

20. The system of claim 18 , wherein the host system remains operational throughout the communication link being disconnected and connected after the predetermined amount of time.