Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965415AbcJXUhV (ORCPT ); Mon, 24 Oct 2016 16:37:21 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:39599 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965354AbcJXUhS (ORCPT ); Mon, 24 Oct 2016 16:37:18 -0400 Subject: Re: [PATCH 3/6] sparc64: Initialize iommu_map_table and iommu_pool To: David Miller References: <1476123127-24314-1-git-send-email-tushar.n.dave@oracle.com> <1476123127-24314-4-git-send-email-tushar.n.dave@oracle.com> <20161024.134750.374485400910042905.davem@davemloft.net> Cc: chris.hyser@oracle.com, sowmini.varadhan@oracle.com, vgupta@synopsys.com, robin.murphy@arm.com, jroedel@suse.de, egtvedt@samfundet.no, krzk@kernel.org, rkuo@codeaurora.org, sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org From: tndave Message-ID: <91dd06dd-22bd-c50a-4a6f-f45334b13b4a@oracle.com> Date: Mon, 24 Oct 2016 13:36:54 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 MIME-Version: 1.0 In-Reply-To: <20161024.134750.374485400910042905.davem@davemloft.net> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1185 Lines: 34 On 10/24/2016 10:47 AM, David Miller wrote: > From: Tushar Dave > Date: Mon, 10 Oct 2016 11:12:04 -0700 > >> Like legacy IOMMU, use common iommu_map_table and iommu_pool for ATU. >> This change initializes iommu_map_table and iommu_pool for ATU. >> >> Signed-off-by: Tushar Dave >> Reviewed-by: chris hyser >> Reviewed-by: Sowmini Varadhan > > I suspect you are adding a bisection problem here. > > It looks to me like patch #2 starts setting up to use the ATU > but these changes in #3 and later are necessary for it to even > work properly. > > You can't leave the tree in an intermediate non-working state > between changes like that. I agree but even if you apply only patch #1, #2 things still work using legacy IOMMU. (and the same is true for rest of the other patches i.e. #3, #4, #5). All the patches, except patch #6 , sets up needed data structures and functions for ATU however ATU will only be used in action after you apply patch #6 which actually enables 64bit DMA. Until then, things are going to work using legacy IOMMU with 32bit DMA. Thanks. -Tushar >