From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Neuendorffer Subject: RE: [PATCH] of/fdt: Add unflatten_partial_device_tree Date: Tue, 29 Jun 2010 09:52:40 -0700 Message-ID: <44507ccb-5378-4fc4-9654-37fe1d335deb@SG2EHSMHS003.ehs.local> References: <20100629012207.GG13509@yookeroo> <20100629.102503.835458634865560451.imp@bsdimp.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Class: urn:content-classes:message In-Reply-To: <20100629.102503.835458634865560451.imp-uzTCJ5RojNnQT0dZR+AlfA@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: "M. Warner Losh" , glikely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org Cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org List-Id: devicetree@vger.kernel.org > -----Original Message----- > From: devicetree-discuss-bounces+stephen.neuendorffer=xilinx.com-uLR06cmDAlaKREJ1Ck/qmQ@public.gmane.org org [mailto:devicetree- > discuss-bounces+stephen.neuendorffer=xilinx.com-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org] On Behalf Of M. Warner Losh > Sent: Tuesday, June 29, 2010 9:25 AM > To: glikely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org > Cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org > Subject: Re: [PATCH] of/fdt: Add unflatten_partial_device_tree > > In message: > Grant Likely writes: > : > : >> Another question is what to do with the unflattened tree once it is > : >> unflattened. Some of the existing code expects the node to be part of > : >> the global tree. Those could either be refactored, or the new partial > : >> tree could be grafted into the global tree. Grafting will have the > : >> least impact, but it probably isn't a good idea in the long term. > : >> Grafting together unrelated trees seems messy to me. > : > > : >I think I must have missed an earlier discussion. What's the use case > : >for multiple fdt blobs? > : > : FPGA on an add-on board in an x86 host. Device tree fragment > : describes the fpga design. There could be multiple boards in a > : system. > > How do you imagine these fragments getting loaded into the system? Not sure yet. We also been working on partially reconfiguring the FPGAs, too: My current thought is that the 'base design' has a fixed FPGA structure and a single corresponding device tree: For convenience I've hardcoded this device tree into the pci device driver, although it should probably be separated out. Independently, the FPGA design may also have a 'reconfigurable' part, which can be configured by giving a (separate) device driver an FPGA bitstream and another device tree description. >>From the 'parse a device tree' perspective, the problems are the same, it's just a matter of whether it is a device tree that describes hardware which is relatively static or relatively more dynamic. Steve This email and any attachments are intended for the sole use of the named recipient(s) and contain(s) confidential information that may be proprietary, privileged or copyrighted under applicable law. If you are not the intended recipient, do not read, copy, or forward this email message or any attachments. Delete this email message and any attachments immediately.