From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752981AbcFFWcS (ORCPT ); Mon, 6 Jun 2016 18:32:18 -0400 Received: from mout.kundenserver.de ([212.227.126.130]:50417 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752632AbcFFWcQ (ORCPT ); Mon, 6 Jun 2016 18:32:16 -0400 From: Arnd Bergmann To: Mark Rutland Cc: Bill Mills , rmk+kernel@armlinux.org.uk, t-kristo@ti.com, ssantosh@kernel.org, catalin.marinas@arm.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, r-woodruff2@ti.com, devicetree@vger.kernel.org Subject: Re: [RFC v2 4/4] ARM: keystone: dma-coherent with safe fallback Date: Mon, 06 Jun 2016 14:37:24 +0200 Message-ID: <4810162.vDdHVxWF0U@wuerfel> User-Agent: KMail/5.1.3 (Linux/4.4.0-22-generic; KDE/5.18.0; x86_64; ; ) In-Reply-To: <20160606114256.GF6831@leverpostej> References: <1465183229-24147-1-git-send-email-wmills@ti.com> <5480709.cGbSehIKrE@wuerfel> <20160606114256.GF6831@leverpostej> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V03:K0:bu03AtY+t77xhAbIsW+7OiR8ovmkw2FnpqfscLGsJHBrCnzF58L AM+zmMBOrxlY+0QwO4ermYseYAhAJizC741mKib3MOwBbBN6YW+gCxoXWufJG/qvnL+BNCY Pgj2aBaJlqqPphtGAxwXU9l0u9XFXKpmILKUlUt2fV400ka8j4lPuu4sg1zsp/RAPiaK7DG 8JKfINxshUg/sLd/n6aJw== X-UI-Out-Filterresults: notjunk:1;V01:K0:jNcsNrupTjI=:xh2c1kcn5FORQ2CCEq/sRi j3cTPwDxw7Ho6ZMPBIWJ0ObR41pcYYDUOVJLzU211O4Grc6eXIpJEIJfOA2FWOmCT0gmqWJKT niIeIXJe1ZGp4mKxQcwH97jxMTAypq7wOgRT0fGom+oRdMXpw1ike1GwdMRVvQbBNLGV1PwK7 Qj2ARcpGvD8XTHNmqP35SCQQcKI7Scyq0Iixlf+uiAYWkP+WotNCgPuIn/SRFcpBExCrevi2V rQiy/7h68gxvtNCX8uiXvu/oXd+8ouDxX40p8KRyI+y/U9tVuzgLCr1X7UmNSWzzj/is313+6 Ei/+hPbFlo4HuqIA7cC7Ci/SNkvP2bi2f1LnhqUBA/s9DVCnJMhAxOfApQ5mzt1P5WIuELdGp HsUJoZ4y+MC+xzIbQWnoLQK2jaA31l1lxuOp2RwXc4IB+vteOGwW8AKl8rWlAsmRdOkIv4Tlb P+WdSjEjb2ybwPx0rRXuKIeKLrA1XLiqIZmDq3mVPgkr5SP1Nrx+yO/Sn9gp86IrM7rZbAlMM p94iAIibgXlFx0DqdZVg2DLcRB7m4gkYcdBPQF6DHnA6GInizT7/016ztF0ZPX72xk5wEGuTb SN8Q7xj+Dd7neNh+eNdmHiMDITRSsAurKbNvi0NRP97cbZOXGlvkwXjgdez6/LNvQIU0QK2+s Dm6bTDOa0jw7SK2Pvww4ovaZgQjv0u/5RMvhorktrlIneEgWSuxHYSoSEGSq6Q9ZpvYCMpbXp O/7rqJ/4cXeerdTD Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Monday, June 6, 2016 12:42:56 PM CEST Mark Rutland wrote: > On Mon, Jun 06, 2016 at 11:09:07AM +0200, Arnd Bergmann wrote: > > On Monday, June 6, 2016 9:56:27 AM CEST Mark Rutland wrote: > > > > So far, the assumption has been: > > > > - when running a non-LPAE kernel, keystone is not coherent, and we > > must ignore both the dma-coherent properties in devices and the > > dma-ranges properties in bus nodes. > > I wasn't able to spot if/where that was enforced. Is it possible to boot > Keystone UP, !LPAE? With !LPAE, no devices are coherent, so that should work with both SMP and and UP. Not sure about LPAE with coherent devices on UP, IIRC we had a bug in that configuration on Armada XP, as the memory was not marked as sharable at all there, and ended up not being coherent with DMA masters. My first guess is that uniprocessor mode on keystone has not been tested at all (TI's QA seems to test only a very limited number of configurations), so it may or may not work. Arnd