From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754647Ab3CXTLP (ORCPT ); Sun, 24 Mar 2013 15:11:15 -0400 Received: from webmail.solarflare.com ([12.187.104.25]:59289 "EHLO webmail.solarflare.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754309Ab3CXTLO (ORCPT ); Sun, 24 Mar 2013 15:11:14 -0400 Message-ID: <1364152267.3620.31.camel@deadeye.wl.decadent.org.uk> Subject: Re: [PATCH] Fix IXP4xx coherent allocations From: Ben Hutchings To: David Miller CC: , , , , Date: Sun, 24 Mar 2013 19:11:07 +0000 In-Reply-To: <20130323.195740.2108147521543354261.davem@davemloft.net> References: <20130323.195740.2108147521543354261.davem@davemloft.net> Organization: Solarflare Communications Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.4.4-2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Originating-IP: [88.96.1.126] X-TM-AS-Product-Ver: SMEX-10.0.0.1412-7.000.1014-19744.005 X-TM-AS-Result: No--21.877800-0.000000-31 X-TM-AS-User-Approved-Sender: Yes X-TM-AS-User-Blocked-Sender: No Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2013-03-23 at 19:57 -0400, David Miller wrote: > From: Krzysztof Halasa > Date: Sat, 23 Mar 2013 20:35:46 +0100 > > > ARM core code currently requires coherent DMA mask to be set. Make sure > > we limit PCI devices to 64 MiB while allowing on-chip devices to access > > the whole 4 GiB address space. > > > > This fixes a v3.7+ regression which broke IXP4xx built-in network devices. > > > > Signed-off-by: Krzysztof Hałasa > > This requirement is not reasonable. > > The DMA API documentation clearly states what the default must be, > and what drivers are guarenteed will be the default. I'm failing to see where it says the default can't be narrower than 32 bits due to platform limits. And how do you think DMA mapping is supposed to work for PCI devices on these platforms, anyway? Ben. -- Ben Hutchings, Staff Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked. From mboxrd@z Thu Jan 1 00:00:00 1970 From: bhutchings@solarflare.com (Ben Hutchings) Date: Sun, 24 Mar 2013 19:11:07 +0000 Subject: [PATCH] Fix IXP4xx coherent allocations In-Reply-To: <20130323.195740.2108147521543354261.davem@davemloft.net> References: <20130323.195740.2108147521543354261.davem@davemloft.net> Message-ID: <1364152267.3620.31.camel@deadeye.wl.decadent.org.uk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Sat, 2013-03-23 at 19:57 -0400, David Miller wrote: > From: Krzysztof Halasa > Date: Sat, 23 Mar 2013 20:35:46 +0100 > > > ARM core code currently requires coherent DMA mask to be set. Make sure > > we limit PCI devices to 64 MiB while allowing on-chip devices to access > > the whole 4 GiB address space. > > > > This fixes a v3.7+ regression which broke IXP4xx built-in network devices. > > > > Signed-off-by: Krzysztof Ha?asa > > This requirement is not reasonable. > > The DMA API documentation clearly states what the default must be, > and what drivers are guarenteed will be the default. I'm failing to see where it says the default can't be narrower than 32 bits due to platform limits. And how do you think DMA mapping is supposed to work for PCI devices on these platforms, anyway? Ben. -- Ben Hutchings, Staff Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.