Re: Dma addr should use Kuseg1 for MIPS32?

[Sergei Shtylyov <sshtylyov@ru.mvista.com>]

Hello.

figo zhang wrote:

>
>     > i write dma_phy to DMA base register, but why it cannot work? it
>     should
>     > write Kseg1 space to DMA register?
>     > I remember that it is ok for ARM/X86 .
>
>     It's only happens to work on some systems.
>
>
> in my puzzle, if i run 
> dma_vaddr =(char*) __get_free_pages(GFP_KERNEL,  order);
> dma_phy = virt_to_phy(dma_vaddr);
>
> if the result is:
> dma_vaddr = 0x801b00000;
> dma_phy = 0x1b00000;
>
> so i should write 0x1b00000 to my DMA Base register or wirte 
> (0x1b000000 | 0xa0000000) to DMA?

   You must always use the physical addresses when programming DMA, i.e. 
0x1b00000 in this case.

WBR, Sergei