From mboxrd@z Thu Jan 1 00:00:00 1970 From: thierry.reding@gmail.com (Thierry Reding) Date: Wed, 15 Oct 2014 11:10:44 +0200 Subject: [PATCH 2/2] iommu: Implement a dummy bus_set_iommu() In-Reply-To: <20140818165750.GE9809@8bytes.org> References: <1406897113-20099-1-git-send-email-thierry.reding@gmail.com> <1406897113-20099-2-git-send-email-thierry.reding@gmail.com> <20140818165750.GE9809@8bytes.org> Message-ID: <20141015091043.GA13162@ulmo> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, Aug 18, 2014 at 06:57:50PM +0200, Joerg Roedel wrote: > On Fri, Aug 01, 2014 at 02:45:13PM +0200, Thierry Reding wrote: > > From: Thierry Reding > > > > This allows IOMMU drivers to compile even if IOMMU_API is not selected > > and helps improve compile coverage. > > IOMMU drivers usually implement the IOMMU-API, so they have a strong > dependency to it. Why do you want to compile-test an iommu driver > without testing the iommu core-code as well? It seems like I never got back to you on this. The reason here is that for Tegra the IOMMU is part of a larger IP block. The IP block is primarily a memory controller with a bunch of configuration knobs for arbitration, prioritization and whatnot. A smaller part of the device does the IOMMU translation. Therefore the IOMMU implementation would be part of a larger driver, and having this dummy would reduce the amount of #ifdefs required. bus_set_iommu() is also the only function in include/linux/iommu.h that doesn't have a dummy, so it seemed like a natural thing to do. That said, I can work around this being absent for !IOMMU_API. Thierry -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 819 bytes Desc: not available URL: