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=-7.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,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 6C4EAC4727C for ; Mon, 21 Sep 2020 22:23:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 228F323A63 for ; Mon, 21 Sep 2020 22:23:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600727017; bh=N9RzAc6C05t2rxlnw7lSRzYBzP947+Ts1bAKMsLmjEU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=y9/fG5oArwoY/41kQrocXJAoj9GCNDfq5AmQ3FIJVyHLrU6LIcbwu6SasXrvI2IH5 K4awMAjHtpTk3varIZ1HISyzi8NuKTcZ4I+2WDNXgyuaJO0zVhoRGzEbPPSbdYA3s7 NC+zK7/hmZVkH6Dke24oASfaSELb2wsdoTgNTYe8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728511AbgIUWXg (ORCPT ); Mon, 21 Sep 2020 18:23:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:42542 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726457AbgIUWXf (ORCPT ); Mon, 21 Sep 2020 18:23:35 -0400 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 7B21723A62; Mon, 21 Sep 2020 22:23:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600727015; bh=N9RzAc6C05t2rxlnw7lSRzYBzP947+Ts1bAKMsLmjEU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=CluYU3j+OZ6XbzXp4elhUn92tatuqzSObk4WseHK3gulRNfFdoM3XXQ7GgS+G4xvK kvbtvWJXZAgYM3RJzYV8SaGS1CNoGPsNIvg1Xs/mnOCkm/yQVAzQJYYmJEmvpr+nPl 7Rqin2VNlKQqbOYisp71I5TxrLYGu6uPZozrpNj8= Date: Mon, 21 Sep 2020 23:23:30 +0100 From: Will Deacon To: Robin Murphy Cc: Sai Prakash Ranjan , freedreno@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Akhil P Oommen , dri-devel@lists.freedesktop.org, "Kristian H . Kristensen" , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCHv4 1/6] iommu/io-pgtable-arm: Add support to use system cache Message-ID: <20200921222329.GA4409@willie-the-truck> References: <3b1beb6cf6a34a44b0ecff9ec5a2105b5ff91bd4.1599832685.git.saiprakash.ranjan@codeaurora.org> <20200921180318.GG3141@willie-the-truck> <9646dd4f-f1e6-992d-b8a0-0f2c14fa9fe8@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9646dd4f-f1e6-992d-b8a0-0f2c14fa9fe8@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 21, 2020 at 11:03:49PM +0100, Robin Murphy wrote: > On 2020-09-21 19:03, Will Deacon wrote: > > On Fri, Sep 11, 2020 at 07:57:18PM +0530, Sai Prakash Ranjan wrote: > > > Add a quirk IO_PGTABLE_QUIRK_SYS_CACHE to override the > > > attributes set in TCR for the page table walker when > > > using system cache. > > > > I wonder if the panfrost folks can reuse this for the issue discussed > > over at: > > > > https://lore.kernel.org/r/cover.1600213517.git.robin.murphy@arm.com > > Isn't this all hinged around the outer cacheability attribute, rather than > shareability (since these are nominally NC mappings and thus already > properly Osh)? The Panfrost issue is just about shareability domains being a > bit wonky; the cacheability attributes there are actually reasonably normal > (other than not having a non-cacheable type at all, only a choice of > allocation policies...) Hmm, yes, this quirk _also_ changes the cacheability settings which isn't what we need. It's a bit grotty having two different ways to configure these TCR bits (i.e. a quirk and a format), but at least the mali format rejects all of the quirks so I suppose it's not the end of the world. Will