Hi Simon, On Sun, Feb 24, 2013 at 11:08 PM, Simon Glass <[email protected]> wrote: > Hi Jagan, > > On Sun, Feb 24, 2013 at 8:19 AM, Jagan Teki <[email protected]> wrote: >> Hi Simon, >> >> Thanks for your response, please find my below comments. >> >> On Sun, Feb 24, 2013 at 9:24 PM, Simon Glass <[email protected]> wrote: >>> Hi Jagan, >>> >>> On Thu, Feb 21, 2013 at 9:03 AM, Jagan Teki <[email protected]> >>> wrote: >>>> Hi All, >>>> >>>> I am planning to use devicetree on u-boot. >>>> I have an experience to work with devicetree on Linux. >>>> >>>> For u-boot, I have read doc from doc/README.fdt-control. >>>> I see some dts usages on tegra boards. >>>> >>>> I have lot of confusions with the concept itself. >>>> >>>> Is Linux and u-boot devicetree concept and build system are same? >>> >>> I don't really understand this question sorry. U-Boot and Linux use >>> the device tree mainly for run-time configuration of drivers, so that >>> the same driver code can operate on different boards. >> >> I am some how confusing the fdt usage in u-boot. >> Because when compared to Linux, u-boot fdt setup mandatory to require >> the CONFIG_DEFAULT_DEVICE_TREE >> on the config file [from your previous comments]. >> >> is this the only difference when compared to Linux i guess..is it? >> Linux defconfig file does need to hot-code >> the dts. > > Yes - that is a difference. Linux provides a way to build .dts files > but it is not mandatory. At present it is mandatory with U-Boot, and > only one file is built. It can easily be ignored though.
Ok. > >> >>> >>>> >>>> Suppose I have 4 boards J1, J2, J3 & J4 on my soc "emb".of vendor "vast" >>>> For this requirement I have >>>> board/vast/dts/J1.dts >>>> board/vast/dts/J2.dts >>>> board/vast/dts/J3.dts >>>> board/vast/dts/J4.dts >>>> >>>> include/configs/emb_common.h ==> single configuration of all SOC >>>> needed definitions >>>> like defconfig in Linux. >>>> >>>> do I need any more files? >>> >>> That's enough for the basics I think. >> >> Is dtsi file require to add it on arch folder along with above. > > If your architecture is not one of those already supported (like arm > tegra/exynos and x86) then yes you need to add this file in > arch/<arch>/dts. What architecture are you using? My architecture is armv7, may be for me dtsi not required as arm is existing architecture to support fdt on u-boot.. is it? > >> >>> >>>> >>>> In emb_common.h i am defining >>>> CONFIG_OF_SEPARATE is it sufficient? >>> >>> And CONFIG_OF_CONTROL >>> >>>> >>>> My plan is to build u-boot and then build the dtb with specific >>>> board and then combine. >>> >>> That's fine, and is how we do things on Chromium also. U-Boot tries to >>> build an FDT even with CONFIG_OF_SEPARATE, so you need to put a >>> default device tree file in your emb_common.h file that it can find. >>> But you can ignore it, and for flashing your boards just use >>> u-boot.bin plus whatever .dtb you want to select. >> >> So I will add the fdt support and then build the u-boot. >> Is there any separate u-boot build command to build dts file. >> My plan is to combine both u-boot and dtb. > > You can run dtc yourself if you like - see Makefile/dts for how it is > done there. Once you have the .dtb binary, the easiest thing is to add > it to the end of u-boot.bin, as described in README.fdt-control. Thanks, I tried with above setup for adding dts. I have added simple dts file on my board. I got the below build error /proj/mypc/u-boot/include/asm/gpio.h:1:27: fatal error: asm/arch/gpio.h: No such file or directory compilation terminated. make[1]: *** No rule to make target `.depend.fdtdec', needed by `.depend'. Stop. is gpio.h is mandatory for fdt build? Thanks, Jagan. > >> >> Thanks, >> Jagan. >> >>> >>>> >>>> I saw that all tegra boards config files are defining >>>> CONFIG_DEFAULT_DEVICE_TREE if ie. the case dts is a compile time >>>> option right. >>>> am i correct? >>> >>> Yes - see above. This is convenient for testing and development. >>> >>>> >>>> Please let me know your inputs. >>> >>> Regards, >>> Simon >>> >>>> >>>> -- >>>> Thanks, >>>> Jagan. _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
