On Mon, Oct 18, 2004 at 10:30:15AM +0100, Conor McLoughlin wrote: > I have been looking at the ethernet device driver (fcc_enet) for the > mpc82xx platform. This allocates buffer descriptors using kmalloc with > the GFP_DMA flag. As far as I can see on my platform, this allocates
GFP_DMA has no meaning on PPC. All memory is DMAable. GFP_DMA is for PeeCees with a limited ISA DMA space. Drivers should be using GFP_KERNEL so they don't confuse people. > from the regular kernel memory (0xCxxxxxxx). As the attributes of this > block of memory are controlled by the block address translation > registers, this cannot be DMA safe, can it? Sure it can. It works with hardware snooping. > Is there something I am missing here? Yes, it's a 603e core and hardware snooping support manages cache coherency between system memory and devices. -Matt
