Input/output (I/O) expansion response processing in a peripheral component interconnect express (PCIE) environment

1. A method for implementing non-standard input/output (I/O) adapters in a standardized I/O architecture, the method comprising:

receiving, at an I/O hub, a request from a requester to perform an operation on one of the I/O adapters;

determining that the request is in a format other than a format supported by an I/O bus;

determining that the requester requires a completion response for the request;

determining whether the operation generates the completion response;

based on determining that the operation generates the completion response:

transforming the request into the format supported by the I/O bus;

transmitting the request to the I/O adapter;

receiving the completion response from the I/O adapter, the completion response comprising an indicator that the request has been completed, the completion response in the format supported by the I/O bus; and

transmitting the completion response to the requester; and

based on determining that the operation does not generate the completion response:

generating a new request, the new request in a format supported by an I/O bus;

transforming the header of the new request to include the address of the I/O adapter; and

sending the new request to the host system via the I/O bus,

wherein the completion response is in a format not supported by the I/O bus and the new request is in a format not supported by the I/O adapter and a requester, the requester initiating the request.

2. The method of claim 1 , wherein the I/O bus is a PCIe bus.

3. The method of claim 1 , wherein the format of the request an I/O expansion format.

4. The method of claim 1 , wherein the I/O adapter comprises at least one I/O expansion adapter and at least one PCIe adapter.

5. The method of claim 1 , wherein the transformed request is in a format not supported by the I/O adapter and the requester.

6. The method of claim 1 , further comprising:

determining that the request is a request to store data; and

storing information about the requester in the I/O hub in response to the determining, the information comprising:

the requester address;

the operation code, the operation code identifying the operation that is to be performed; and

an indicator indicating that a response is required.

7. A method for implementing non-standard input/output (I/O) adapters in a standardized I/O architecture, the method comprising:

receiving, at an I/O adapter, a request for an operation, the request indicating that a completion response to the request is required, the completion response comprising an address of the I/O adapter and a response code;

determining that the operation does not generate the completion response;

generating a new request, the new request in a format supported by an I/O bus;

transforming the header of the new request to include the address of the I/O adapter; and

sending the new request to the host system via the I/O bus,

wherein the completion response is in a format not supported by the I/O bus and the new request is in a format not supported by the I/O adapter and a requester, the requester initiating the request.

8. The method of claim 7 , wherein the I/O bus is a PCIe bus.

9. The method of claim 7 , wherein the format of the completion response is an I/O expansion format.

10. The method of claim 7 , wherein the I/O adapter comprises an I/O expansion adapter, the I/O expansion adapter sharing the I/O bus with at least one PCIe adapter.

11. The method of claim 7 , wherein the new request is generated in response to determining that the request is a write request.