From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37935) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y9CFE-00043q-2c for qemu-devel@nongnu.org; Thu, 08 Jan 2015 07:31:21 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Y9CF9-000893-Rm for qemu-devel@nongnu.org; Thu, 08 Jan 2015 07:31:20 -0500 Received: from lhrrgout.huawei.com ([194.213.3.17]:45798) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y9CF9-00088Y-JF for qemu-devel@nongnu.org; Thu, 08 Jan 2015 07:31:15 -0500 Message-ID: <54AE787F.3050906@huawei.com> Date: Thu, 8 Jan 2015 13:30:55 +0100 From: Claudio Fontana MIME-Version: 1.0 References: <1420560191-48029-1-git-send-email-agraf@suse.de> <1420560191-48029-4-git-send-email-agraf@suse.de> <54AD5640.9000606@huawei.com> In-Reply-To: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 3/4] arm: Add PCIe host bridge in virt machine List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Maydell Cc: Rob Herring , "Michael S. Tsirkin" , QEMU Developers , Ard Biesheuvel , Alvise Rigo , Stuart Yoder , Alexander Graf On 08.01.2015 11:31, Peter Maydell wrote: > On 7 January 2015 at 15:52, Claudio Fontana wrote: >> Interrupt map does not seem to work for me; incidentally this ends up being >> the same kind of undocumented blob that Alvise posted in his series. Can >> you add a good comment about what the ranges property contains >> (the 0x01000000, 0x02000000 which I suspect means IO vs MMIO IIRC, but >> there is no need to be cryptic about it). > > The binding docs live in the kernel: > https://www.kernel.org/doc/Documentation/devicetree/bindings/pci/host-generic-pci.txt > (which reference the upstream openfirmware specs): > http://www.firmware.org/1275/practice/imap/imap0_9d.pdf > > so we can provide a brief summary comment here, but if the kernel > binding docs are confusing (which they kind of are) we should really > get them improved... > > On the 'compatible' string: > https://www.kernel.org/doc/Documentation/devicetree/bindings/pci/host-generic-pci.txt > doesn't say anything about using "pci" here in either the > text or the example binding. Thank you for these pointers. I think that putting a comment with this information (even just a pointer to the effect of "just look at host-generic-pci.txt in the Linux kernel documentation to understand what's going on here" would be helpful, or even go directly referring to the "Open Firmware Recommended Practice: Interrupt Mapping", since QEMU should be guest OS agnostic - to some extent.. -). Also I think Alex' proposal to use defines for IO Space vs Memory Space instead of hardcoding 0x1000000 / 0x2000000 is a good thing. I think the kernel binding docs could be made more helpful, but since I am in the position of trying to figure this stuff out I am not in the best position to make them better.. Thanks, Claudio