From mboxrd@z Thu Jan 1 00:00:00 1970 From: gregory.clement@free-electrons.com (Gregory CLEMENT) Date: Fri, 05 Apr 2013 22:59:59 +0200 Subject: [PATCH v2 1/9] arm: mvebu: Limit the DMA zone when LPAE is selected In-Reply-To: <201304052241.14865.arnd@arndb.de> References: <1365193444-13441-1-git-send-email-gregory.clement@free-electrons.com> <1365193444-13441-2-git-send-email-gregory.clement@free-electrons.com> <201304052241.14865.arnd@arndb.de> Message-ID: <515F3B4F.3070505@free-electrons.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 04/05/2013 10:41 PM, Arnd Bergmann wrote: > On Friday 05 April 2013, Gregory CLEMENT wrote: >> When LPAE is activated on Armada XP, all registers and IOs are still >> 32bit, the 40bit extension is on the CPU to DRAM path (windows) only. >> That means that all the DMA transfer are restricted to the low 32 bits >> address space. This is limitation is achieved by selecting ZONE_DMA. >> >> Signed-off-by: Gregory CLEMENT > > > Shouldn't that be ZONE_DMA32? > Well common code for ARM don't manage the ZONE_DMA32. Whereas with ZONE_DMA, setup_dma_zone() in arch/arm/mm/init.c does exactly what I want: setting arm_dma_limit to 0xffffffff. ZONE_DMA32 is used on arm64 however. > Arnd > -- Gregory Clement, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gregory CLEMENT Subject: Re: [PATCH v2 1/9] arm: mvebu: Limit the DMA zone when LPAE is selected Date: Fri, 05 Apr 2013 22:59:59 +0200 Message-ID: <515F3B4F.3070505@free-electrons.com> References: <1365193444-13441-1-git-send-email-gregory.clement@free-electrons.com> <1365193444-13441-2-git-send-email-gregory.clement@free-electrons.com> <201304052241.14865.arnd@arndb.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <201304052241.14865.arnd@arndb.de> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Arnd Bergmann Cc: Lior Amsalem , Andrew Lunn , Ike Pan , Grant Likely , David Marlin , Yehuda Yitschak , Tawfik Bayouk , Dan Frazier , Eran Ben-Avi , Ezequiel Garcia , Leif Lindholm , Sebastian Hesselbarth , Jason Cooper , Nadav Haklai , Jon Masters , devicetree-discuss@lists.ozlabs.org, Rob Herring , linux-arm-kernel@lists.infradead.org, Thomas Petazzoni , Chris Van Hoof , Nicolas Pitre , linux-kernel@vger.kernel.org, Maen Suleiman List-Id: devicetree@vger.kernel.org On 04/05/2013 10:41 PM, Arnd Bergmann wrote: > On Friday 05 April 2013, Gregory CLEMENT wrote: >> When LPAE is activated on Armada XP, all registers and IOs are still >> 32bit, the 40bit extension is on the CPU to DRAM path (windows) only. >> That means that all the DMA transfer are restricted to the low 32 bits >> address space. This is limitation is achieved by selecting ZONE_DMA. >> >> Signed-off-by: Gregory CLEMENT > > > Shouldn't that be ZONE_DMA32? > Well common code for ARM don't manage the ZONE_DMA32. Whereas with ZONE_DMA, setup_dma_zone() in arch/arm/mm/init.c does exactly what I want: setting arm_dma_limit to 0xffffffff. ZONE_DMA32 is used on arm64 however. > Arnd > -- Gregory Clement, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422631Ab3DEVAT (ORCPT ); Fri, 5 Apr 2013 17:00:19 -0400 Received: from mail.free-electrons.com ([94.23.35.102]:41013 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1162169Ab3DEVAR (ORCPT ); Fri, 5 Apr 2013 17:00:17 -0400 Message-ID: <515F3B4F.3070505@free-electrons.com> Date: Fri, 05 Apr 2013 22:59:59 +0200 From: Gregory CLEMENT User-Agent: Mozilla/5.0 (X11; Linux i686; rv:17.0) Gecko/20130308 Thunderbird/17.0.4 MIME-Version: 1.0 To: Arnd Bergmann CC: Jason Cooper , Andrew Lunn , Grant Likely , Rob Herring , Thomas Petazzoni , Ezequiel Garcia , linux-arm-kernel@lists.infradead.org, devicetree-discuss@lists.ozlabs.org, linux-kernel@vger.kernel.org, Olof Johansson , Nicolas Pitre , Lior Amsalem , Maen Suleiman , Tawfik Bayouk , Shadi Ammouri , Eran Ben-Avi , Yehuda Yitschak , Nadav Haklai , Ike Pan , Chris Van Hoof , Dan Frazier , Leif Lindholm , Jon Masters , David Marlin , Sebastian Hesselbarth Subject: Re: [PATCH v2 1/9] arm: mvebu: Limit the DMA zone when LPAE is selected References: <1365193444-13441-1-git-send-email-gregory.clement@free-electrons.com> <1365193444-13441-2-git-send-email-gregory.clement@free-electrons.com> <201304052241.14865.arnd@arndb.de> In-Reply-To: <201304052241.14865.arnd@arndb.de> X-Enigmail-Version: 1.5.1 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/05/2013 10:41 PM, Arnd Bergmann wrote: > On Friday 05 April 2013, Gregory CLEMENT wrote: >> When LPAE is activated on Armada XP, all registers and IOs are still >> 32bit, the 40bit extension is on the CPU to DRAM path (windows) only. >> That means that all the DMA transfer are restricted to the low 32 bits >> address space. This is limitation is achieved by selecting ZONE_DMA. >> >> Signed-off-by: Gregory CLEMENT > > > Shouldn't that be ZONE_DMA32? > Well common code for ARM don't manage the ZONE_DMA32. Whereas with ZONE_DMA, setup_dma_zone() in arch/arm/mm/init.c does exactly what I want: setting arm_dma_limit to 0xffffffff. ZONE_DMA32 is used on arm64 however. > Arnd > -- Gregory Clement, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com