From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org ([103.22.144.67]:46905 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752866AbbDHDbr (ORCPT ); Tue, 7 Apr 2015 23:31:47 -0400 Message-ID: <1428463905.29968.2.camel@ellerman.id.au> Subject: Re: [PATCH v2 04/19] powerpc: Create pci_controller_ops.dma_dev_setup and shim From: Michael Ellerman To: Arnd Bergmann Cc: Daniel Axtens , wangyijing@huawei.com, linux-pci@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Date: Wed, 08 Apr 2015 13:31:45 +1000 In-Reply-To: <2489424.TEiBTfgpvS@wuerfel> References: <1427778057-9505-1-git-send-email-dja@axtens.net> <5500778.Q4t9Fg7Irn@wuerfel> <1428366696.22268.28.camel@axtens.net> <2489424.TEiBTfgpvS@wuerfel> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org List-ID: On Tue, 2015-04-07 at 09:44 +0200, Arnd Bergmann wrote: > On Tuesday 07 April 2015 10:31:36 Daniel Axtens wrote: > > > Please see https://patchwork.ozlabs.org/patch/431333/ for related work. > > > > > I'm familiar with that patch series - I've been helping Yijing get it up > > to speed on PowerPC. > > > > > > > I think it would be better not to introduce another architecture-specific > > > pci host bridge operations structure, but instead consolidate into > > > the one that is already there. We are also adding a generic way to set up > > > PCI DMA, so it would seems reasonable to hook into that place. > > I see what you're getting at, and I agree that we want to move towards > > generic operations. > > > > However, I think this should go in as is at this point, for two main > > reasons: > > > > 1) This is a good midpoint that makes it easier to move to a generic > > structure. Our arch specific stuff is quirky and difficult. This patch > > series does a lot to reduce the complexity, and would make it very easy > > to move these ops into a generic structure at some future point. > > > > 2) Trying to go generic at this point risks making the change set so > > complex and wide ranging that it will really struggle to get in. For > > example, Yijing's patch set, despite not changing any of the quirky > > stuff in PowerPC, is already quite long, and will require agreement from > > a lot of people before it can go in. > > > > Much as I would like to have everything as generic as possible, if we > > were to try to do the whole job in one go, it'd become a big, difficult, > > messy patch set, and would be less likely to happen than if we were to > > do it in two steps. > > Ok, fair enough. Let's do this one first then. Thanks Arnd. cheers