From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Brook Subject: Re: [Qemu-devel] CELF Project Proposal - Device tree support for QEMU system emulation. Date: Tue, 22 Dec 2009 12:45:48 +0000 Message-ID: <200912221245.48495.paul@codesourcery.com> References: <200912162246.42366.rob@landley.net> <4B2A94BB.4020200@codemonkey.ws> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4B2A94BB.4020200-rdkfGonbjUSkNkDKm+mE6A@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: devicetree-discuss-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org Errors-To: devicetree-discuss-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org To: qemu-devel-qX2TKyscuCcdnm+yROfE0A@public.gmane.org Cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, Anthony Liguori , CE Linux Developers List List-Id: devicetree@vger.kernel.org > http://thread.gmane.org/gmane.comp.emulators.qemu/44869 > > I'm not sure why Paul never pushed it but I think he was able to create > the syborg board purely from a device tree. The patches referenced above include purely device-tree based Syborg and Stellaris boards. It works fairly nicely for some embedded boards, but gets fairly hairy when you start considering more complex topologies/machines. I particular the PCI OF/FDT bindings don't really fit what we need for qemu. Obviously full qdev conversion is a prerequisite for device tree based configuration, and at that time qdev was still in its infancy. Part of the reason for posting that patch was to demonstrate the abstraction layers required for the internal device model. Previous patches tended to be based on the pre-existing PC commandline options, which IMO is a mistake. Likewise if (like my implementation) you focus on embedded machines you risk serious problems trying to extend to server class machines. Paul From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1NN47l-0008Cf-8q for qemu-devel@nongnu.org; Tue, 22 Dec 2009 07:46:01 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1NN47g-0008AX-G2 for qemu-devel@nongnu.org; Tue, 22 Dec 2009 07:46:00 -0500 Received: from [199.232.76.173] (port=54431 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1NN47g-0008AS-BP for qemu-devel@nongnu.org; Tue, 22 Dec 2009 07:45:56 -0500 Received: from mx20.gnu.org ([199.232.41.8]:10703) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1NN47g-0000MF-89 for qemu-devel@nongnu.org; Tue, 22 Dec 2009 07:45:56 -0500 Received: from mail.codesourcery.com ([38.113.113.100]) by mx20.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1NN47d-0006Hk-Vv for qemu-devel@nongnu.org; Tue, 22 Dec 2009 07:45:54 -0500 From: Paul Brook Subject: Re: [Qemu-devel] CELF Project Proposal - Device tree support for QEMU system emulation. Date: Tue, 22 Dec 2009 12:45:48 +0000 References: <200912162246.42366.rob@landley.net> <4B2A94BB.4020200@codemonkey.ws> In-Reply-To: <4B2A94BB.4020200@codemonkey.ws> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <200912221245.48495.paul@codesourcery.com> List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: devicetree-discuss@lists.ozlabs.org, CE Linux Developers List > http://thread.gmane.org/gmane.comp.emulators.qemu/44869 > > I'm not sure why Paul never pushed it but I think he was able to create > the syborg board purely from a device tree. The patches referenced above include purely device-tree based Syborg and Stellaris boards. It works fairly nicely for some embedded boards, but gets fairly hairy when you start considering more complex topologies/machines. I particular the PCI OF/FDT bindings don't really fit what we need for qemu. Obviously full qdev conversion is a prerequisite for device tree based configuration, and at that time qdev was still in its infancy. Part of the reason for posting that patch was to demonstrate the abstraction layers required for the internal device model. Previous patches tended to be based on the pre-existing PC commandline options, which IMO is a mistake. Likewise if (like my implementation) you focus on embedded machines you risk serious problems trying to extend to server class machines. Paul