From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grant Grundler Date: Tue, 26 Oct 2004 17:55:52 +0000 Subject: Re: ia64 implementation of lib/iomap.c Message-Id: <20041026175552.GD2728@cup.hp.com> List-Id: References: <16759.51459.598187.91726@napali.hpl.hp.com> In-Reply-To: <16759.51459.598187.91726@napali.hpl.hp.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org On Tue, Oct 26, 2004 at 09:23:24AM -0700, Jesse Barnes wrote: > I'm pretty sure this is the case. Me too. (Re perf sensitive devices NOT using IO Port address space) > In fact when I last discussed this with > Linus he indicated that an ioread shouldn't guarantee DMA completion either, > which would mean we could reuse the read_relaxed stuff to implement it. How can a device driver guarantee all in-flight DMA has completed before unmapping control data? (ie buffers allocated with pci_alloc_consistent()). PCI ordering rules dictate MMIO read flush in-flight inbound DMA. I'm just looking for a replacement if there is going to be a difference in semantics between readl() and io_readl(). thanks, grant