Hot plug process in a distributed interconnect bus

1. A method of supporting a hot-plug process triggered by a change in a status of a distributed peripheral component interconnect express (PCIe) bus, comprising:

copying a second configuration space from a second bridge to an upstream bus unit when the distributed link is available;

checking by a root component directly coupled to a first bridge included in the upstream bus unit if the distributed link is unavailable;

if the distributed link is determined to be unavailable, asserting a hot-plug interrupt by a second configuration space indicating a hot-plug event, by copying the second configuration space to the upstream bus unit; and

accessing the configuration space of the second bridge stored in the upstream bus unit during a hot-plug removal process performed by an operating system (OS)

wherein the upstream bus unit including the first bridge communicates with the second bridge over the distributed link.

2. The method of claim 1 , wherein the second configuration space includes at least hot-plug registers (HPR) specifying at least capabilities and status of the second bridge.

3. The method of claim 2 , wherein the hot-plug registers include at least a slot control register, a slot status register, and a slot capabilities register.

4. The method of claim 3 , wherein the hot-plug registers are updated using a configuration write packet.

5. The method of claim 1 , wherein a new version of the second configuration space is copied to the upstream bus unit upon any change in the second configuration space.

6. The method of claim 1 , wherein the hot-plug removal process performed by the operating system depends on the type of the operating system.

7. A method of supporting a hot-plug process triggered by a change in a status of a distributed peripheral component interconnect express (PCIe) bus, comprising:

upon establishment of the distributed link, copying a second configuration space of the second bridge from the upstream bus unit to the second bridge;

updating a first configuration space of a first bridge included in the upstream bus unit and the second configuration space on a hot-plug insertion event indicating that the distributed link transmits from an unavailable to an available state;

asserting a hot-plug interrupt by a copy of the second configuration space in the upstream bus unit if the distributed link is available, the hot-plug interrupt informing on a hot-plug insertion event; and

accessing the second configuration space stored in the second bridge during a hot-plug insertion process performed by an operating system (OS)

wherein the upstream bus unit including the first bridge communicates with the second bridge over the distributed link.

8. The method of claim 7 , wherein the second configuration space includes at least hot-plug registers specifying at least capabilities and status of a slot of the second bridge and the first configuration space bridge includes at least hot-plug registers specifying at least capabilities and status of a slot of the first bridge.

9. The method of claim 8 , wherein the hot-plug registers include at least a slot control register, a slot status register, and a slot capabilities register.

10. The method of claim 9 , wherein the hot-plug registers are updated using a configuration write packet.

11. The method of claim 1 , wherein the hot-plug insertion process performed by the operating system depends on the type of the operating system.

12. A non-transitory computer readable medium having stored thereon instructions for causing one or more processing units to execute the method according to claim 7 .

13. A distributed PCIe adapted to support a hot-plug process triggered by any change in a status of a distributed link, comprising:

an upstream bus unit including a first bridge connected to a root component and adapted to maintain a first configuration space and a copy of a second configuration space,

the first configuration space bridge includes at least hot-plug registers specifying at least capabilities and status of a slot of the first bridge; and

a second bridge connected to an endpoint component and adapted to maintain the second configuration space,

the second configuration space includes at least hot-plug registers specifying at least capabilities and status of a slot of the second bridge

wherein the upstream bus unit including the first bridge communicates with the second bridge over the distributed link.

14. The distributed PCIe of claim 13 , when the distributed link status changes from available to unavailable a hot-plug removal event is triggered.

15. The distributed PCIe of claim 14 , wherein the second configuration space is copied to the upstream bus unit when the link is available.

16. The distributed PCIe of claim 15 , wherein the second configuration space in the second bridge is updated with the hot-plug removal event.

17. The distributed PCIe of claim 16 , wherein an operating system accesses the copy of the second configuration space in the first bridge during a hot-plug removal process performed by the operating system.

18. The distributed PCIe of claim 14 , wherein when the distributed link status changes from unavailable to available is a hot-plug insertion event.

19. The distributed PCIe of claim 18 , wherein the copy of the second configuration space is copied from the upstream bus unit to the second bridge.

20. The distributed PCIe of claim 19 , wherein the operating system accesses the second configuration space in the second bridge during a hot-plug insertion process performed by the operating system.