From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 1 Apr 2004 14:00:18 -0800 From: Eugene Surovegin To: "Michael R. Zucca" Cc: John Whitney , Dan Malek , Matt Porter , linuxppc-dev@lists.linuxppc.org Subject: Re: Problems with dma_alloc_coherent() Message-ID: <20040401220018.GA4130@gate.ebshome.net> References: <9EB527A2-83F5-11D8-9FF0-000A95A07384@sands-edge.com> <20040401100546.A27472@home.com> <4317F0F4-8405-11D8-9FF0-000A95A07384@sands-edge.com> <20040401181926.GA3630@gate.ebshome.net> <406C658E.10500@embeddededge.com> <20040401185956.GB3786@gate.ebshome.net> <2C2F00BD-8410-11D8-9FF0-000A95A07384@sands-edge.com> <20040401191715.GC3786@gate.ebshome.net> <406C8104.9050609@acm.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <406C8104.9050609@acm.org> Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: On Thu, Apr 01, 2004 at 03:52:20PM -0500, Michael R. Zucca wrote: > > >I think we should add such info to a structure which describes the _bus_, > >not > >_device_. > >I'm not "new-device-model" guru, so I cannot comment _how_ this can be > >implemented though :) > > A bus description alone is not sufficient. A generic DMA API should take > both a source and destination device. well, DMA API we are talking about handles only device <-> system memory, so only _one_ device (which is currently done) is need. > Between any two sources and > destinations there may be several intervening bridges, which potentially > means programming those bridges and/or doing several address translations. In case of several bridges, I think it's simpler just to assign _different_ buses for each bus connected by a bridge. Eugene. ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/