From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH v2 1/3] devicetree: bindings: Document qcom,msm-id and qcom,board-id Date: Tue, 10 Mar 2015 20:52:01 +0100 Message-ID: <10886228.vUHyKm1ubP@wuerfel> References: <1425503602-24916-1-git-send-email-galak@codeaurora.org> <3A588B25-66ED-4BB5-8C8F-D050D8A2F9F3@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <3A588B25-66ED-4BB5-8C8F-D050D8A2F9F3@codeaurora.org> Sender: linux-arm-msm-owner@vger.kernel.org To: Kumar Gala Cc: Olof Johansson , Kevin Hilman , linux-arm-msm , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "arm@kernel.org" , "devicetree@vger.kernel.org" , Heiko =?ISO-8859-1?Q?St=FCbner?= List-Id: devicetree@vger.kernel.org On Tuesday 10 March 2015 13:10:08 Kumar Gala wrote: > >>>>>>>>> The top level qcom,msm-id and qcom,board-id are utilized by= bootloaders > >>>>>>>>>> on Qualcomm MSM platforms to determine which device tree s= hould be > >>>>>>>>>> utilized and passed to the kernel. > >>>>>>>>>>=20 > >>>>>>>>>> Cc: > >>>>>>>>>> Signed-off-by: Kumar Gala > >>>>>>>>>=20 > >>>>>>>>> Is this the special magic that allows qcom bootloaders to t= ake a kernel > >>>>>>>>> plus multiple DTBs and figure out which DTB to pass? > >>>>>>>>>=20 > >>>>>>>>> Kevin > >>>>>>>>=20 > >>>>>>>> yes > >>>>>>>=20 > >>>>>>> That's a bummer. > >>>>>>>=20 > >>>>>>> Luckily, the solution for upstream is still quite simple: Pro= vide only > >>>>>>> one devicetree, and it'll be used, right? > >>>>>>=20 > >>>>>> We can provide only one, we still need the IDs in the DT. > >>>>>=20 > >>>>> How are the DTS provided? Concatenated with the kernel, or in a > >>>>> wrapped data format? Or in a separate partition from the kernel= ? > >>>>=20 > >>>> Its a wrapped data format that is than concatenated with the ker= nel if I remember correctly. > >>>=20 > >>> Then you should be able to create a tool that can write this conc= atenated > >>> format and insert these properties from a table that matches the = boot > >>> loader, right? > >>>=20 > >>> Arnd > >>=20 > >> Are you suggesting the tool insert the properties in the DT? I=E2= =80=99m not sure I understand what the point of doing that would be. > >=20 > > To insert platform-local properties that mean nothing outside of th= e > > firmware packaging of the device trees, which is the case here? > >=20 > > I think the idea of having the installer script inserting them is > > quite reasonable in this case. > >=20 > >=20 > > -Olof >=20 > These values are static, so not sure what the point of having the ins= taller script do that? >=20 It combines two hacks to work around a nonstandard boot loader. Once the bootloader is fixed, you can stop using that script. Arnd