Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965867AbcKKBuo (ORCPT ); Thu, 10 Nov 2016 20:50:44 -0500 Received: from galahad.ideasonboard.com ([185.26.127.97]:55501 "EHLO galahad.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965040AbcKKBum (ORCPT ); Thu, 10 Nov 2016 20:50:42 -0500 From: Laurent Pinchart To: Robin Murphy Cc: Magnus Damm , iommu@lists.linux-foundation.org, laurent.pinchart+renesas@ideasonboard.com, geert+renesas@glider.be, joro@8bytes.org, linux-kernel@vger.kernel.org, linux-renesas-soc@vger.kernel.org, horms+renesas@verge.net.au, m.szyprowski@samsung.com Subject: Re: [PATCH v6 05/07] iommu/ipmmu-vmsa: Add new IOMMU_DOMAIN_DMA ops Date: Fri, 11 Nov 2016 03:50:44 +0200 Message-ID: <16618395.kRQakkIJXR@avalon> User-Agent: KMail/4.14.10 (Linux/4.8.6-gentoo; KDE/4.14.24; x86_64; ; ) In-Reply-To: <941ff264-8f9f-e0e6-2b50-bdd3e19946e5@arm.com> References: <20161019233533.10506.16810.sendpatchset@little-apple> <20161019233623.10506.49016.sendpatchset@little-apple> <941ff264-8f9f-e0e6-2b50-bdd3e19946e5@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2360 Lines: 80 Hi Robin, On Friday 21 Oct 2016 18:52:53 Robin Murphy wrote: > On 20/10/16 00:36, Magnus Damm wrote: > > From: Magnus Damm > > > > Introduce an alternative set of iommu_ops suitable for 64-bit ARM > > as well as 32-bit ARM when CONFIG_IOMMU_DMA=y. Also adjust the > > Kconfig to depend on ARM or IOMMU_DMA. > > > > Signed-off-by: Magnus Damm > > --- > > > > Changes since V5: > > - Made domain allocation/free code more consistent - thanks Joerg! > > > > Changes since V4: > > - Added Kconfig hunk to depend on ARM or IOMMU_DMA > > > > Changes since V3: > > - Removed group parameter from ipmmu_init_platform_device() > > > > Changes since V2: > > > > - Included this new patch from the following series: > > [PATCH 00/04] iommu/ipmmu-vmsa: IPMMU CONFIG_IOMMU_DMA update > > > > - Use only a single iommu_ops structure with #ifdef CONFIG_IOMMU_DMA > > - Folded in #ifdefs to handle CONFIG_ARM and CONFIG_IOMMU_DMA > > - of_xlate() is now used without #ifdefs > > - Made sure code compiles on both 32-bit and 64-bit ARM. > > > > drivers/iommu/Kconfig | 1 > > drivers/iommu/ipmmu-vmsa.c | 122 ++++++++++++++++++++++++++++++++++++--- > > 2 files changed, 115 insertions(+), 8 deletions(-) [snip] > > --- 0006/drivers/iommu/ipmmu-vmsa.c > > +++ work/drivers/iommu/ipmmu-vmsa.c 2016-10-20 08:16:48.440607110 +0900 [snip] > > -static struct iommu_domain *ipmmu_domain_alloc(unsigned type) > > -{ > > - if (type != IOMMU_DOMAIN_UNMANAGED) > > - return NULL; > > I *think* that if we did the initial check thus: > > if (type != IOMMU_DOMAIN_UNMANAGED || > (IS_ENABLED(CONFIG_IOMMU_DMA) && type != IOMMU_DOMAIN_DMA)) > return NULL; I assume you meant if (type != IOMMU_DOMAIN_UNMANAGED && (!IS_ENABLED(CONFIG_IOMMU_DMA) || type != IOMMU_DOMAIN_DMA)) return NULL; But how about just if (type != IOMMU_DOMAIN_UNMANAGED && type != IOMMU_DOMAIN_DMA)) return NULL; as type will never be set to IOMMU_DOMAIN_DMA on ARM32 ? > it shouldn't be necessary to split the function at all - we then just > wrap the {get,put}_cookie() bits in "if (type == IOMMU_DOMAIN_DMA)" and > in the 32-bit ARM case they just don't run as that can never be true. > > > - > > - return __ipmmu_domain_alloc(type); > > -} > > - -- Regards, Laurent Pinchart