Method and apparatus for handling bus master and direct memory access
(DMA) requests at an I/O controller
    2.
    发明授权
    Method and apparatus for handling bus master and direct memory access (DMA) requests at an I/O controller 失效
    用于在I / O控制器处理总线主控和直接存储器访问(DMA)请求的方法和装置

    公开(公告)号:US5862387A

    公开(公告)日:1999-01-19

    申请号:US884023

    申请日:1997-06-27

    摘要: A computer system that implements a direct memory access (DMA) request passing protocol. The computer system may comprise a Peripheral Component Interconnect (PCI) bus that includes an electrical interface as specified by a PCI Local Bus standard. The PCI bus is coupled to at least one DMA agent and a DMA controller. The DMA agent issues DMA requests to the DMA controller using the electrical interface of the PCI bus. According to one embodiment, a system I/O controller receives the DMA requests and passes them on to the DMA controller, which arbitrates the DMA requests and passes back a grant to the system I/O controller. The system I/O controller uses the electrical interface of the PCI bus to pass the grant to the DMA agent. The same DMA request passing protocol may be implemented in any bus having an electrical interface that specifies a unique request signal line for each bus agent of the bus.

    摘要翻译: 实现直接内存访问(DMA)请求传递协议的计算机系统。 计算机系统可以包括外围组件互连(PCI)总线,其包括由PCI本地总线标准指定的电接口。 PCI总线耦合到至少一个DMA代理和DMA控制器。 DMA代理使用PCI总线的电接口向DMA控制器发出DMA请求。 根据一个实施例,系统I / O控制器接收DMA请求并将它们传递到DMA控制器,DMA控制器对DMA请求进行仲裁,并将授权传回给系统I / O控制器。 系统I / O控制器使用PCI总线的电接口将授权传递给DMA代理。 相同的DMA请求传递协议可以在具有为总线的每个总线代理指定唯一请求信号线的电接口的任何总线中实现。