Hi Jegan, On Sun, Feb 24, 2013 at 9:45 AM, Jagan Teki <jagannadh.t...@gmail.com> wrote: > Hi Simon, > > On Sun, Feb 24, 2013 at 11:08 PM, Simon Glass <s...@chromium.org> wrote: >> Hi Jagan, >> >> On Sun, Feb 24, 2013 at 8:19 AM, Jagan Teki <jagannadh.t...@gmail.com> wrote: >>> Hi Simon, >>> >>> Thanks for your response, please find my below comments. >>> >>> On Sun, Feb 24, 2013 at 9:24 PM, Simon Glass <s...@chromium.org> wrote: >>>> Hi Jagan, >>>> >>>> On Thu, Feb 21, 2013 at 9:03 AM, Jagan Teki <jagannadh.t...@gmail.com> >>>> 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?
Which sub-arch? If it is tegra/exynos5250 then you might be OK. For something else, you should get the kernel's .dtsi file for that chip. > >> >>> >>>> >>>>> >>>>> 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? Yes because basic GPIO support is included. You can create one for your sub-arch and make it #include <asm-generic/gpio.h> as a starting point. Regards, Simon > > 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 U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
