From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thierry Reding Subject: [PATCH 1/4] iommu/exynos: Play nice in multi-platform builds Date: Wed, 4 Feb 2015 08:58:07 +0100 Message-ID: <1423036690-3862-2-git-send-email-thierry.reding@gmail.com> References: <1423036690-3862-1-git-send-email-thierry.reding@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1423036690-3862-1-git-send-email-thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Joerg Roedel Cc: Nicolas Chauvet , iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Kukjin Kim List-Id: iommu@lists.linux-foundation.org From: Thierry Reding The Exynos System MMU driver unconditionally executes code and registers a struct iommu_ops with the platform bus irrespective of whether it runs on an Exynos SoC or not. This causes problems in multi-platform kernels where drivers for other SoCs will no longer be able to register their own struct iommu_ops or even try to use a struct iommu_ops for an IOMMU that obviously isn't there. The smallest fix I could think of is to check for the existence of any Exynos System MMU devices in the device tree and skip initialization otherwise. This fixes a problem on Tegra20 where the DRM driver will try to use the obviously non-existent Exynos System MMU. Reported-by: Nicolas Chauvet Cc: Kukjin Kim Signed-off-by: Thierry Reding --- drivers/iommu/exynos-iommu.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c index 7ce52737c7a1..d4b41fa32368 100644 --- a/drivers/iommu/exynos-iommu.c +++ b/drivers/iommu/exynos-iommu.c @@ -1188,6 +1188,9 @@ static int __init exynos_iommu_init(void) { int ret; + if (!of_find_matching_node(NULL, sysmmu_of_match)) + return 0; + lv2table_kmem_cache = kmem_cache_create("exynos-iommu-lv2table", LV2TABLE_SIZE, LV2TABLE_SIZE, 0, NULL); if (!lv2table_kmem_cache) { -- 2.1.3