| 摘要 |
According to one embodiment, the host controller includes a register set to issue command, and a direct memory access (DMA) unit and accesses a system memory and a device. First, second, third and fourth descriptors are stored in the system memory. The first descriptor includes a set of a plurality of pointers indicating a plurality of second descriptors. Each of the second descriptors comprises the third descriptor and fourth descriptor. The third descriptor includes a command number, etc. The fourth descriptor includes information indicating addresses and sizes of a plurality of data arranged in the system memory. The DMA unit sets, in the register set, the contents of the third descriptor forming the second descriptor, from the head of the first descriptor as a start point, and transfers data between the system memory and the host controller in accordance with the contents of the fourth descriptor. |
