From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH V6 08/13] PCI: generic, thunder: update to use generic ECAM API Date: Sat, 16 Apr 2016 09:31:59 +0200 Message-ID: <4240660.NqlPcXaV7N@wuerfel> References: <1460740008-19489-1-git-send-email-tn@semihalf.com> <5110401.mGEq6IVFz2@wuerfel> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: Received: from mout.kundenserver.de ([217.72.192.75]:50104 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750993AbcDPHd2 (ORCPT ); Sat, 16 Apr 2016 03:33:28 -0400 In-Reply-To: Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Jayachandran C Cc: linux-arm-kernel@lists.infradead.org, Tomasz Nowicki , Bjorn Helgaas , Will Deacon , Catalin Marinas , rafael@kernel.org, Hanjun Guo , Lorenzo Pieralisi , Sinan Kaya , jiang.liu@linux.intel.com, Jon Masters , linaro-acpi@lists.linaro.org, linux-pci@vger.kernel.org, Liviu.Dudau@arm.com, David Daney , linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, robert.richter@caviumnetworks.com, Suravee.Suthikulpanit@amd.com, msalter@redhat.com, Wangyijing , Marcin Wojtas On Saturday 16 April 2016 12:50:13 Jayachandran C wrote: > > > > I still think it would be better to keep the loadable PCI host drivers > > separate from the ACPI PCI infrastructure. There are a number of > > simplifications that we want to do to the DT based drivers in the long > > run, so it's better if that code is not shared at this level. Abstracting > > out the ECAM code is fine, but at that point you should be able to just > > call it from the ACPI layer. > > The issue is not with this patch (in my opinion). This patch is just > re-arranging how thunder specific data is maintained. Earlier it was > a container_of gen_pci, now it is ->priv of pci_config_window. > > I can see the issue in patches 12 and 13 of this patchset which adds > ACPI fixups into the thunder OF driver. Right, I commented on this one, because it seems to rearrange the code in order to do the later one. > The simple approach when doing modular PCI drivers would be to make > pci-thunder-*.c like pci-host-common.c, to be compiled in if configured. > The fie will contain all the Thunder quirks and can export > pci_thunder_ecam_ops. I would argue that we should not export anything from drivers/pci/host, those should really be standalone drivers that do not interact with other subsystems. How much code would you need to duplicate from thunder-ecam to have the same functionality available in ACPI? My expectation is that it's not really that much more compared to the code you need for sharing a single implementation, but you get a lower complexity here, which makes it easier to understand and to rework. Arnd