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Altera_Forum's avatar
Altera_Forum
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17 years ago

Linux 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_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

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Moreover, the author is forgetting that the DMA is working in the physical address world,

so we need to set the pointers of descripters like 


//    desc->source = read_addr;
    desc->source = virt_to_phys(read_addr);
//    desc->destination = write_addr;
    desc->destination = virt_to_phys(write_addr);
//    desc->next = (unsigned int *)next;
    desc->next = (unsigned int *)((unsigned long)next & 0x1fffffffUL);
and so on.

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The current altera_tse code works, but does not do this translation. Any idea why setting virtual addresses here actually does work?