From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laurent Pinchart Subject: Re: [PATCH 2/4] iommu/omap: Play nice in multi-platform builds Date: Wed, 04 Feb 2015 16:31:55 +0200 Message-ID: <1718219.kRa6INVfJa@avalon> References: <1423036690-3862-1-git-send-email-thierry.reding@gmail.com> <1423036690-3862-3-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: <1423036690-3862-3-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: Thierry Reding Cc: Nicolas Chauvet , Tony Lindgren , iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org List-Id: iommu@lists.linux-foundation.org Hi Thierry, Thank you for the patch. On Wednesday 04 February 2015 08:58:08 Thierry Reding wrote: > From: Thierry Reding > > The OMAP IOMMU driver unconditionally executes code and registers a > struct iommu_ops with the platform bus irrespective of whether it runs > on an OMAP 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 > OMAP IOMMU 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 OMAP IOMMU. > > Reported-by: Nicolas Chauvet > Cc: Tony Lindgren > Cc: Suman Anna > Cc: Laurent Pinchart > Signed-off-by: Thierry Reding > --- > drivers/iommu/omap-iommu.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c > index bbb7dcef02d3..e4d4f133a3b3 100644 > --- a/drivers/iommu/omap-iommu.c > +++ b/drivers/iommu/omap-iommu.c > @@ -1377,6 +1377,9 @@ static int __init omap_iommu_init(void) > const unsigned long flags = SLAB_HWCACHE_ALIGN; > size_t align = 1 << 10; /* L2 pagetable alignement */ > > + if (!of_find_matching_node(NULL, omap_iommu_of_match)) > + return 0; > + We should convert the omap-iommu driver to proper DT instantiation, but this should do for now. > p = kmem_cache_create("iopte_cache", IOPTE_TABLE_SIZE, align, flags, > iopte_cachep_ctor); > if (!p) > @@ -1394,6 +1397,9 @@ subsys_initcall(omap_iommu_init); > > static void __exit omap_iommu_exit(void) > { > + if (!of_find_matching_node(NULL, omap_iommu_of_match)) > + return; > + > kmem_cache_destroy(iopte_cachep); > > platform_driver_unregister(&omap_iommu_driver); The exit function will never be called as the omap-iommu driver is always built-in. You could just remove the exit function. -- Regards, Laurent Pinchart