From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Szyprowski Subject: Re: [PATCH v5 11/18] iommu: exynos: remove useless device_add/remove callbacks Date: Mon, 26 Jan 2015 13:06:07 +0100 Message-ID: <54C62DAF.6020809@samsung.com> References: <1422028288-891-1-git-send-email-m.szyprowski@samsung.com> <1422028288-891-12-git-send-email-m.szyprowski@samsung.com> <2829552.kzfCU5HyxQ@avalon> <20150126110059.GC30345@8bytes.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-reply-to: <20150126110059.GC30345-zLv9SwRftAIdnm+yROfE0A@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 , Laurent Pinchart Cc: Thierry Reding , linux-samsung-soc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Shaik Ameer Basha , Joonyoung Shim , Arnd Bergmann , Rob Herring , Inki Dae , Seung-Woo Kim , Will Deacon , Tomasz Figa , linaro-mm-sig-cunTk1MwBs8s++Sfvej+rw@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Kukjin Kim , Kyungmin Park , Cho KyongHo , David Wodhouse , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: iommu@lists.linux-foundation.org Hello, On 2015-01-26 12:00, Joerg Roedel wrote: > Hi Laurent, > > On Sun, Jan 25, 2015 at 05:38:22PM +0200, Laurent Pinchart wrote: >> IOMMU groups still seem a bit unclear to me. Will Deacon has nicely explained >> what they represent in >> http://lists.infradead.org/pipermail/linux-arm-kernel/2014-December/310816.html. >> The IOMMU core doesn't make groups >> mandatory, but requires them in some code paths. >> >> For example the coldplug device add function add_iommu_group() called for all >> devices already registered when bus_set_iommu() is called will try to warn of >> devices added multiple times with a WARN_ON(dev->iommu_group). Another example >> is the iommu_bus_notifier() function which will call the remove_device() >> operation only when dev->iommu_group isn't NULL. >> >> I'm thus unsure whether groups should be made mandatory, or whether the IOMMU >> core should be fixed to make them really optional (or, third option, whether >> there's something I haven't understood properly). > My plan is to make IOMMU groups mandatory. I am currently preparing and > RFC patch-set to introduce default-domains (which will be per group). So > when all IOMMU drivers are converted to make use of default domains the > iommu groups will be mandatory. Thanks for the comment, I will implement all that will be needed for it to exynos iommu driver, but I would like to ask if you plan to merge my existing patches for exynos iommu driver to your tree? Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland