From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Gunthorpe Subject: Re: RDMA/cxgb4: Support on-chip SQs Date: Wed, 30 Jan 2013 14:44:25 -0700 Message-ID: <20130130214425.GA5674@obsidianresearch.com> References: <20130130210006.GA22134@elgon.mountain> <51099270.5070406@opengridcomputing.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <51099270.5070406-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Steve Wise Cc: Dan Carpenter , linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Roland Dreier List-Id: linux-rdma@vger.kernel.org On Wed, Jan 30, 2013 at 03:36:48PM -0600, Steve Wise wrote: > I wonder, then, what the correct service is to get the cpu physical > address from a kernel virtual address returned from > dma_alloc_coherent()? I think this is correct as-is, since I think > dma_alloc_coherent() falls under the "directly mapped" addresses in > the virt_to_phys() prototype comment. DMA-API.txt says: This routine allocates a region of bytes of consistent memory. It also returns a which may be cast to an unsigned integer the same width as the bus and used as the physical address base of the region. So instead of virt_to_phys you should use dma_addr?? I think the note about 'directly mapped' refers to things the arch setups during early boot, not dma_alloc stuff. Jason -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html