From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Vasut Subject: Re: [RFC] devicetree: new FDT format version Date: Thu, 25 Jan 2018 10:14:38 +0100 Message-ID: <90983180-ae3b-5a31-9dc0-b62b978a0fba@gmail.com> References: <20180123124232.GA14832@umbus> <20328477-e511-e875-7dc4-253640f2219e@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20328477-e511-e875-7dc4-253640f2219e-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Content-Language: en-US Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Frank Rowand , David Gibson , Rob Herring Cc: Devicetree Compiler , "devicetree-spec-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Jon Loeliger , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Pantelis Antoniou , "Pantelis Antomarek.vasut-Re5JQEeQqe/2sr8fMPgRzw@public.gmane.org" , Grant Likely , Tom Rini , Kyle Evans , Geert Uytterhoeven , Alan Tull , Michael Ellerman List-Id: devicetree@vger.kernel.org On 01/23/2018 10:17 PM, Frank Rowand wrote: [...] > My knowledge of bootloader use of the FDT is nearly non-existent, so > I'm on thin ice here. But I am guessing that a lot of bootloader > processing of FDT data could be removed if the kernel would unflatten > a chained FDT and overlay FDT(s). > > Comments from the bootloader folks on this topic would be much > appreciated. U-Boot, when using DT as a hardware-description (rather than just passing it to Linux) usually operates on the FDT, unless explicitly configured to unflatten the tree. That later option is not enabled by default. The reason for that is so that the DT can be accessed very early on, at which point there may not be any other memory available than a very limited stack and the FDT blob can still be located in some read-only memory. -- Best regards, Marek Vasut -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html