From mboxrd@z Thu Jan 1 00:00:00 1970 From: "David S. Miller" MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <14980.19083.144384.865666@pizda.ninka.net> Date: Fri, 9 Feb 2001 11:52:43 -0800 (PST) Subject: Re: IOMMU setup vs DAC (PCI) In-Reply-To: <200102091947.LAA66193@google.engr.sgi.com> References: <200102091939.LAA08207@milano.cup.hp.com> <200102091947.LAA66193@google.engr.sgi.com> Sender: owner-linux-mm@kvack.org Return-Path: To: Kanoj Sarcar Cc: Grant Grundler , linux-mm@kvack.org List-ID: Kanoj Sarcar writes: > dma_addr_t should be unsigned long, which is 64 bits on 64 bit > architectures, so things are fine there. > > On regular x86, dma_addr_t is u32, which still works. It's 32-bit on sparc64 since 32-bit DMA addresses are all we need since the IOMMU is used for anything. In fact, if your architecture is doing nothing other than PCI, you _OUGHT_ to make it 32-bit even on 64-bit platforms because the PCI dma interface does not support 64-bit DACs in any way shape or form until 2.5.x in then a new dma64_addr_t type will be used to denote a DAC address. Later, David S. Miller davem@redhat.com -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux.eu.org/Linux-MM/