modules/dma/physical address

Marcus Sundberg erammsu at
Mon Mar 13 21:13:57 EST 2000

duyrat1 <duyrat1 at> writes:

> Hy everybody,
> I think I have found a little source of bug, so please correct me if I
> am wrong :
> Every time we use a dma on the mpc860, we've got to give him the
> physical address
> of a buffer ( the physical addr of a sk_buff in enet.c for exemple ).
> We use __pa which purpose is just to  substract 0xc0000000.
> But when we create a buffer in a module, his virtual addr is not just an
> offset of his physical addr,

Yes it is, if you use __pa on addresses it is intended to be used on.
(Well, to be precise __pa should never be used in drivers at all, you
should use virt_to_phys instead, but in the end they do the same thing
on PPC)

Signature under construction, please come back later.

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