From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: Re: [PATCH V1 16/29] xen/arm: Build DOM0 FDT by browsing the device tree structure Date: Tue, 10 Sep 2013 11:39:38 +0100 Message-ID: <522EF6EA.4050203@linaro.org> References: <1377701263-3319-1-git-send-email-julien.grall@linaro.org> <1377701263-3319-17-git-send-email-julien.grall@linaro.org> <1378726404.19967.67.camel@kazak.uk.xensource.com> <522DBE86.4070607@linaro.org> <1378730395.19967.110.camel@kazak.uk.xensource.com> <522E433E.9070609@linaro.org> <1378803533.21748.27.camel@kazak.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1378803533.21748.27.camel@kazak.uk.xensource.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ian Campbell Cc: stefano.stabellini@eu.citrix.com, andre.przywara@linaro.org, patches@linaro.org, xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On 09/10/2013 09:58 AM, Ian Campbell wrote: > On Mon, 2013-09-09 at 22:53 +0100, Julien Grall wrote: > >>>>> >>>>> This comment is saying that the name of the name property used to be >>>>> something else? What was it? Which version of FDT was that -- do we need >>>>> to care? >>>> >>>> Right, on older FDT version (< 0x10) each node has 2 different name: >>>> - the name just after FDT_BEGIN_NODE in the fdt which correspond to >>>> the "filename". >>>> - the name in property "name" which is a convenient name. >>>> >>>> So we can't use the name field in device tree to retrieve the name to >>>> create the node. >>>> >>>> For the FDT version, I don't know if we need to care. Linux pays >>>> attention to it in the device tree code. >>> >>> I'm not sure we need to care either, I expect we will never see <0x10 in >>> our uses (they are probbaly burnt into the ROMs of PPC machines) but of >>> it is easy enough to so we might as well I guess? >> >> I forgot that there is another issue, the ePAR describes the name has >> node-name@unit-address. The name field will contains node-name and not >> the full node name. >> >> Lets say Xen only uses the field name (ie node-name) to create the FDT >> node name. We Linux will create the procfs for the device tree >> (/proc/devicetree), it's possible to have numerous warning because there >> is 2 nodes with the same name. > > Yes, we need to avoid that. Isn't there a full_name field or something? The full_name field contains the full path to this node, for instance /cpus/cpu@0. So we can retrieve the node-name@unit-address with a basename-like function. > (I've tripped over this in debugging, it's a bit annoying that name is > just node-name and not unit-address too) -- Julien Grall