[email protected] wrote:
> I am doing the following:
>
> malloc some memory is user space
> pass its pointer to some kernel module
> in the kernel module...do a pci_alloc_consistent so that i get a
memory
> region for PCI DMA operations
Wrong approach, you can use kiobufs if you want DMA to the malloc()ed
userspace memory:
* lock down the user memory using map_user_kiobuf() + lock_kiovec()
(see linux/iobuf.h).
* translate the iobuf->maplist into a scatterlist [1]
* feed pci_map_sg() with the scatterlist to get DMA addresses.
you can pass to the hardware.
And the reverse to free everything when you are done of course.
Gerd
[1] IMHO it would be more useful if iobufs would use a scatterlist
instead of an struct page* array.
--
Gerd Knorr <[email protected]> -- SuSE Labs, Au?enstelle Berlin
On Mon, Jul 02 2001, [email protected] wrote:
> [1] IMHO it would be more useful if iobufs would use a scatterlist
> instead of an struct page* array.
No that would be horrible, at least with the current scatterlist. A page
based scatterlist would be alright though -- but this boils down to the
per-page offset debate again.
--
Jens Axboe