AR #22872 - 8.1i EDK - Processor IP Drivers do not support virtual memory
8.1i EDK - Processor IP Drivers do not support virtual memory
| AR# | 22872 |
| Part | IP-Processor |
| Last Modified | 2006-02-16 00:00:00.0 |
| Status | Active |
| Keywords | Processor IP, driver, virtual memory [[EDK sp1]] |
Description
Keywords: Processor IP, driver, virtual memory
The drivers for the IP peripherals do not support virtual-to-physical memory translation. This becomes a problem when DMA is used in applications that use the MMU (e.g., Linux and QNX operating systems).
One example of this is the way in which buffer descriptors are handled. The drivers need to be aware of both the virtual and the physical address of the buffer descriptor. They need the virtual address to set up options inside the buffer descriptor. They need the physical address to provide it to the DMA engine.