Forum Discussion
Altera_Forum
Honored Contributor
Honored ContributorLinux with MMU on NEEK
Hi, all. I'm testing Linux MMU version, on my NEEK. http://www.nioswiki.com/linux It works fine and I can use "bash" shell. This is the evident proof that we are using the true 'fo...
Altera_ForumHonored Contributor
Honored ContributorHi,
--- Quote Start --- The current altera_tse code works, but does not do this translation. Any idea why setting virtual addresses here actually does work? --- Quote End --- In the kernel, a physical address 0x00000000 is translated to the virtual address 0xc0000000 for cached area or 0xe0000000 for non-cached area. For the DMA registers, we must convert these virtual addresses to physical ones again, but the range of physical addresses are limited within 0x00000000~0x1fffffff (that means totally 512MBytes), so the DMA does not use upper 3 bits. Thus we don't need to use the function virt_to_phys(...), because the DMA and Avalon bus will ignore upper 3bits automatically, but this is wrong from the view point of the logic. Kazu
