From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 008B4CA9EAF for ; Thu, 24 Oct 2019 11:21:37 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id BB6DA2166E for ; Thu, 24 Oct 2019 11:21:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="u8SipnXw" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BB6DA2166E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id 7F5AE14C0; Thu, 24 Oct 2019 11:21:37 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 2728914AD for ; Thu, 24 Oct 2019 11:21:36 +0000 (UTC) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id DBEE58AC for ; Thu, 24 Oct 2019 11:21:35 +0000 (UTC) Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 85A6B20856; Thu, 24 Oct 2019 11:21:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571916095; bh=NU8mQb2h0/LjJk0PvHij6/R4e6uRraWEpQjrI463EH8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=u8SipnXw70PK36+xT/cT3Fuxn7r9dNKSH1vKR8iOGQX772FqSLYLIG6XqkZNAw6O3 a/WCPnNSNcnJeq5Jt33NAjktZL20Jsy51ZzLSjByZWszf5VwzdBsW0ohgrU9RvxUtY 6ZD1UW9nmFkN5O20D2wTPL+Zv4NSnU2UClw7Lz2Q= Date: Thu, 24 Oct 2019 12:21:31 +0100 From: Will Deacon To: Sai Prakash Ranjan Subject: Re: Users of IOMMU_QCOM_SYS_CACHE? Message-ID: <20191024112130.GD1242@willie-the-truck> References: <20191024105150.GC1242@willie-the-truck> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Cc: iommu@lists.linux-foundation.org, robin.murphy@arm.com, sspatil@android.com X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org On Thu, Oct 24, 2019 at 04:41:04PM +0530, Sai Prakash Ranjan wrote: > On 2019-10-24 16:21, Will Deacon wrote: > > In commit 90ec7a76cc4b ("iommu/io-pgtable-arm: Add support to use system > > cache") we added support for IOMMU_QCOM_SYS_CACHE which was merged into > > 5.3. > > This allows non-coherent devices to request an outer cacheable memory > > type.... except that nobody actually does this in mainline. I remember > > there > > being a potential DRM user but I don't know what happened to it. > > > > Given that this isn't actually exposed in the DMA API, I worry that > > we're > > just carrying part of an out-of-tree hack here and propose that we drop > > the flag altogether unless we get an upstream user, preferably by > > plumbing > > this into the DMA API via a new attribute. > > > > Thoughts? > > > > There is definitely a user of this coming soon atleast for SC7180 SoC once > we have support for this SoC upstream. Ok, I'm keen to see how you end up using this. How soon is soon? Will _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu