From mboxrd@z Thu Jan 1 00:00:00 1970 From: arnd@arndb.de (Arnd Bergmann) Date: Tue, 10 Mar 2015 20:52:01 +0100 Subject: [PATCH v2 1/3] devicetree: bindings: Document qcom, msm-id and qcom, board-id In-Reply-To: <3A588B25-66ED-4BB5-8C8F-D050D8A2F9F3@codeaurora.org> References: <1425503602-24916-1-git-send-email-galak@codeaurora.org> <3A588B25-66ED-4BB5-8C8F-D050D8A2F9F3@codeaurora.org> Message-ID: <10886228.vUHyKm1ubP@wuerfel> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.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 should be > >>>>>>>>>> utilized and passed to the kernel. > >>>>>>>>>> > >>>>>>>>>> Cc: > >>>>>>>>>> Signed-off-by: Kumar Gala > >>>>>>>>> > >>>>>>>>> Is this the special magic that allows qcom bootloaders to take a kernel > >>>>>>>>> plus multiple DTBs and figure out which DTB to pass? > >>>>>>>>> > >>>>>>>>> Kevin > >>>>>>>> > >>>>>>>> yes > >>>>>>> > >>>>>>> That's a bummer. > >>>>>>> > >>>>>>> Luckily, the solution for upstream is still quite simple: Provide only > >>>>>>> one devicetree, and it'll be used, right? > >>>>>> > >>>>>> We can provide only one, we still need the IDs in the DT. > >>>>> > >>>>> How are the DTS provided? Concatenated with the kernel, or in a > >>>>> wrapped data format? Or in a separate partition from the kernel? > >>>> > >>>> Its a wrapped data format that is than concatenated with the kernel if I remember correctly. > >>> > >>> Then you should be able to create a tool that can write this concatenated > >>> format and insert these properties from a table that matches the boot > >>> loader, right? > >>> > >>> Arnd > >> > >> Are you suggesting the tool insert the properties in the DT? I?m not sure I understand what the point of doing that would be. > > > > To insert platform-local properties that mean nothing outside of the > > firmware packaging of the device trees, which is the case here? > > > > I think the idea of having the installer script inserting them is > > quite reasonable in this case. > > > > > > -Olof > > These values are static, so not sure what the point of having the installer script do that? > It combines two hacks to work around a nonstandard boot loader. Once the bootloader is fixed, you can stop using that script. Arnd