mdaljeet@in.ibm.com 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 <kraxel@bytesex.org> -- SuSE Labs, Außenstelle Berlin - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Tue May 15 2001 - 21:00:40 EST