From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with ESMTP id D1EC26B0169 for ; Mon, 8 Aug 2011 11:30:22 -0400 (EDT) Date: Mon, 8 Aug 2011 16:29:52 +0100 From: Russell King - ARM Linux Subject: Re: [RFC] ARM: dma_map|unmap_sg plus iommu Message-ID: <20110808152952.GA19367@n2100.arm.linux.org.uk> References: <000301cc4dc4$31b53630$951fa290$%szyprowski@samsung.com> <20110729093555.GA13522@8bytes.org> <001901cc4dd8$4afb4e40$e0f1eac0$%szyprowski@samsung.com> <20110729105422.GB13522@8bytes.org> <004201cc4dfb$47ee4770$d7cad650$%szyprowski@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: "Ramirez Luna, Omar" Cc: KyongHo Cho , Marek Szyprowski , Joerg Roedel , linux-arm-kernel@lists.infradead.org, linaro-mm-sig@lists.linaro.org, linux-mm@kvack.org, Kyungmin Park , Arnd Bergmann , Ohad Ben-Cohen On Mon, Aug 08, 2011 at 10:21:46AM -0500, Ramirez Luna, Omar wrote: > Hi, > > On Sun, Jul 31, 2011 at 7:57 PM, KyongHo Cho wrote: > > On Fri, Jul 29, 2011 at 11:24 PM, Marek Szyprowski > ... > >> Right now I have no idea how to handle this better. Perhaps with should be > >> possible > >> to specify somehow the target dma_address when doing memory allocation, but I'm > >> not > >> really convinced yet if this is really required. > >> > > What about using 'dma_handle' argument of alloc_coherent callback of > > dma_map_ops? > > Although it is an output argument, I think we can convey a hint or > > start address to map > > to the IO memory manager that resides behind dma API. > > I also thought on this one, even dma_map_single receives a void *ptr > which could be casted into a struct with both physical and virtual > addresses to be mapped, but IMHO, this starts to add twists into the > dma map parameters which might create confusion. No - don't even consider that. That's highly non-standard usage and it'll break all existing drivers to do so. -- 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-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org