From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: Re: [RFC 4/4] drm: Add NVIDIA Tegra support Date: Wed, 11 Apr 2012 15:35:12 +0200 Message-ID: <20120411133512.GL4296@phenom.ffwll.local> References: <1334146230-1795-1-git-send-email-thierry.reding@avionic-design.de> <1334146230-1795-5-git-send-email-thierry.reding@avionic-design.de> <20120411124810.GK4296@phenom.ffwll.local> <20120411132326.GD27337@avionic-0098.adnet.avionic-design.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20120411132326.GD27337-RM9K5IK7kjIyiCvfTdI0JKcOhU4Rzj621B7CTYaBSLdn68oJJulU0Q@public.gmane.org> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Thierry Reding Cc: Daniel Vetter , linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Stephen Warren , Joerg Roedel , devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, Jon Mayo , iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Colin Cross , Hiroshi Doyu List-Id: linux-tegra@vger.kernel.org On Wed, Apr 11, 2012 at 03:23:26PM +0200, Thierry Reding wrote: > * Daniel Vetter wrote: > > On Wed, Apr 11, 2012 at 02:10:30PM +0200, Thierry Reding wrote: > > > This commit adds a very basic DRM driver for NVIDIA Tegra SoCs. It > > > currently has rudimentary GEM support and can run a console on the > > > framebuffer as well as X using the xf86-video-modesetting driver. > > > Only the RGB output is supported. Quite a lot of things still need > > > to be worked out and there is a lot of room for cleanup. > > > > Indeed, after a quick look there are tons of functions that are just stubs > > ;-) One thing I wonder though is why you directly use the iommu api and > > not wrap it up into dma_map? Is arm infrastructure just not there yet or > > do you plan to tightly integrate the tegra drm with the iommu (e.g. for > > process space switching or similarly funky stuff)? > > I'm not sure I know what you are referring to. Looking for all users of > iommu_map() doesn't turn up anything related to dma_map. Can you point me in > the right direction? Well, you use the iommu api to map/unmap memory into the iommu for tegra, whereas usually device drivers just use the dma api to do that. The usual interface is dma_map_sg/dma_unmap_sg, but there are quite a few variants around. I'm just wondering why this you've choosen this. -Daniel -- Daniel Vetter Mail: daniel-/w4YWyX8dFk@public.gmane.org Mobile: +41 (0)79 365 57 48