DMAC translation mechanism
US7644198B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 7, 2005 |
| Grant date | Jan 5, 2010 |
| Priority date | — |
| Expiry date | Aug 26, 2026 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F13/28
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An improved DMAC translation mechanism is presented. DMA commands are “unrolled” based upon the transfer size of the DMA command and the amount of data that a computer system transfers at one time. For the first DMA request, a DMA queue requests a memory management unit to perform an address translation. The DMA queue receives a real page number from the MMU and, on subsequent rollout requests, the DMA queue provides the real page number to a bus interface unit without accessing the MMU until the transfer crosses into the next page. Rollout logic decrements the DMA command's transfer size after each DMA request, determines whether a new page has been reached, determines if the DMA command is completed, and sends write back information to the DMA queue for subsequent DMA requests.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.