From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx198.postini.com [74.125.245.198]) by kanga.kvack.org (Postfix) with SMTP id 169DD6B0068 for ; Sat, 29 Dec 2012 01:53:51 -0500 (EST) Received: by mail-pa0-f46.google.com with SMTP id bh2so6356461pad.5 for ; Fri, 28 Dec 2012 22:53:50 -0800 (PST) Date: Fri, 28 Dec 2012 22:53:56 -0800 From: Olof Johansson Subject: Re: [PATCH] arm: dma mapping: export arm iommu functions Message-ID: <20121229065356.GA13760@quad.lixom.net> References: <1356592458-11077-1-git-send-email-prathyush.k@samsung.com> <50DC580C.7080507@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: Prathyush K Cc: Marek Szyprowski , Prathyush K , linux-arm-kernel@lists.infradead.org, linaro-mm-sig@lists.linaro.org, linux-mm@kvack.org On Fri, Dec 28, 2012 at 09:53:47AM +0530, Prathyush K wrote: > On Thu, Dec 27, 2012 at 7:45 PM, Marek Szyprowski > wrote: > > > Hello, > > > > > > On 12/27/2012 8:14 AM, Prathyush K wrote: > > > >> This patch adds EXPORT_SYMBOL calls to the three arm iommu > >> functions - arm_iommu_create_mapping, arm_iommu_free_mapping > >> and arm_iommu_attach_device. These functions can now be called > >> from dynamic modules. > >> > > > > Could You describe a bit more why those functions might be needed by > > dynamic modules? > > > > Hi Marek, > > We are adding iommu support to exynos gsc and s5p-mfc. > And these two drivers need to be built as modules to improve boot time. > > We're calling these three functions from inside these drivers: > e.g. > mapping = arm_iommu_create_mapping(&platform_bus_type, 0x20000000, SZ_256M, > 4); > arm_iommu_attach_device(mdev, mapping); The driver shouldn't have to call these low-level functions directly, something's wrong if you need that. How is the DMA address management different here from other system/io mmus? is that 256M window a hardware restriction? -Olof -- 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/ . Don't email: email@kvack.org