Data processing system including buffering mechanism for inbound and outbound reads and posted writes

A method for controlling a plurality of transactions from a first bus to a second bus through a bridge, in a data processing system comprising one or more processors, one or more peripheral devices, a plurality of busses connecting the one or more processors and the one or more peripheral devices through one or more bridges, and one or more bridges for controlling transactions between the first bus and the second bus of the plurality of busses, said method comprising the steps of:

• providing a first data path for handling transactions from the first bus to the second bus;
• providing a second data path for handling transactions from the second bus to the first bus;
• providing a controller for controlling gating and sequence of transactions between the first bus and the second bus through the first data path and the second data path;
• and
• controlling, by the controller, read transactions and write transactions through the first and second data paths in accordance with a predetermined logic structure to eliminate flushing write buffers prior to read transactions being gated through the data paths.

A data processing system, comprising:

• one or more processors;
• one or more peripheral devices;
• a plurality of buses connecting said one or more processors and said one or more peripheral devices through one or more bridges;
• one or more bridges for controlling transactions between a first bus and a second bus of said plurality of buses, each said bridge comprising:
• a plurality of data paths for handling transactions between said first and second buses;
• buffer means for storing write transactions and for storing read transactions, with multiple read and write transactions being allowed to reside in said bridge at the same time;
• and
• a controller for controlling gating and sequence of said read and write transactions between said first and said second bus through said data paths without first flushing said write transactions from said buffer means.

A bus-to-bus bridge, comprising:

• a plurality of data paths for handling transactions between a first bus and a second bus;
• buffer means for storing write transactions and for storing read transactions, with multiple read and write transactions being allowed to reside in said bridge at the same time;
• and
• a controller for controlling gating and sequence of said read and write transactions between said first bus and said second bus through said data paths without first flushing said write transactions from said buffer means.

A method for controlling a plurality of transactions between a first bus and a second bus through a bridge, said method comprising the steps of:

• providing a plurality of data paths in the bridge for handling transactions between said first and second buses;
• storing write transactions in a plurality of buffers in the bridge;
• storing read transactions in said plurality of buffers, with multiple read and write transactions being allowed to reside in said bridge at the same time;
• and
• controlling gating and sequence of said read and write transactions between said first and second buses through said data paths without first flushing said write transactions from said buffers.