From mboxrd@z Thu Jan 1 00:00:00 1970 From: Will Deacon Subject: Re: [PATCH 5/6] iommu/arm-smmu: support buggy implementations with invalidate-on-map Date: Thu, 13 Nov 2014 09:48:26 +0000 Message-ID: <20141113094826.GA13350@arm.com> References: <1407891099-24641-1-git-send-email-mitchelh@codeaurora.org> <1407891099-24641-6-git-send-email-mitchelh@codeaurora.org> <20141112182642.GH26437@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: 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: Mitchel Humpherys Cc: "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org" , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" List-Id: devicetree@vger.kernel.org On Wed, Nov 12, 2014 at 06:58:17PM +0000, Mitchel Humpherys wrote: > On Wed, Nov 12 2014 at 10:26:43 AM, Will Deacon wrote: > > On Wed, Aug 13, 2014 at 01:51:38AM +0100, Mitchel Humpherys wrote: > >> Add a workaround for some buggy hardware that requires a TLB invalidate > >> operation to occur at map time. Activate the feature with the > >> qcom,smmu-invalidate-on-map boolean DT property. > > > > I'm digging up an old thread here, but I've been working on a new page-table > > allocator for the SMMU and looked into implementing this workaround for you > > in there. When I do the TLBI on map after installing the new PTE, can I just > > invalidate the range mapped by that PTE, or does it need to be a full TLBI? > > I'm not totally sure on the history of the hardware errata but I believe > it's just the range mapped by that pte. We use SMMU_CBn_TLBIVA in the > our smmu driver. > > However, let's actually just drop this... It's looking like the targets > we have that will use the arm-smmu driver thankfully won't need this > workaround. Thanks for keeping this in mind though :) Ha, damn, then I don't have a user of the shiny new quirks field I added! I don't think I'll go as far as removing it altogether though... Cheers, Will