pcie mailbox

PCIe mailbox is a mechanism for communication between different devices connected through a PCIe bus. It allows devices to send and receive messages or data without the need for direct memory access (DMA) or interrupts.

The PCIe mailbox consists of a set of registers that are used by a device to send and receive messages. Each device has its own set of registers that are mapped to a specific memory address. When a device wants to send a message, it writes the message into its mailbox registers. The target device can then read the message from its own mailbox registers.

The PCIe mailbox is particularly useful for communication between devices that are not directly connected to each other. For example, a graphics card may use the PCIe mailbox to send commands to a sound card without the need for DMA or interrupts. It can also be used for inter-processor communication (IPC) in multi-processor systems.

Overall, the PCIe mailbox provides a simple and efficient way for devices to communicate with each other over a PCIe bus.