On Thu, May 8, 2008 at 9:10 AM, Fabio Tosetto <[EMAIL PROTECTED]> wrote: > Ok, maybe it's better to start from the beginning. > Now I'm using a Lite5200b board, just to avoid problems with my hardware, > and I'm trying to have a bootable kernel. > > With kernel version 2.6.24.6 I do the following commands > > $ make ARCH=powerpc lite5200_defconfig > $ make ARCH=powerpc CROSS_COMPILE=powerpc-linux-gnu- uImage > > then I copy the arch/powerpc/boot/uImage and a rootfs.uimage on the board, > but uBoot stops at the beginning:
Right; some concepts need to be explained now... There is a major difference between arch/ppc and arch/powerpc. In arch/ppc, the kernel is hard coded with the list of devices in the system. In arch/powerpc, the list of devices is captured in a data structure called the Flattened Device Tree (FDT). fdt data structures are generated from the .dts (device tree source) files in arch/powerpc/boot/dts/. When you build a uImage with arch/ppc, you get a hard coded kernel that works with u-boot: "bootm <kernel_addr> <ramdisk_addr>" When you build a uImage with arch/powerpc, you get a dynamic kernel that needs to be passed the device tree blob on boot. Newer u-boot supports dts booting: "bootm <kernel_addr> <ramdisk_addr> <dt_addr>" or "bootm <kernel_addr> - <dt_addr>" if you're not using a ramdisk. However, if you've got an older u-boot version installed on your board, you need to create an image that binds the device tree into the kernel image. This is called a "cuImage". So, instead of doing "make ARCH=powerpc uImage", you should do "make ARCH=powerpc cuImage.<boardname>". This 'wraps' the kernel with a boot wrapper that includes the device tree blob but maintains compatibility with the old style uImage format. For example, use "make ARCH=powerpc cuImage.lite5200b" to build an image for the lite5200b board. The build scripts will use the lite5200b.dts file in the dts directory for building the image. If you add "fabios-fantastic-board.dts" to arch/powerpc/boot/dts, then you can build "cuImage.fabios-fantastic-board". :-) > The only way I was able to get something working, even though it sounds a > little strange to me, is loading the config from powerpc folder but > compiling in ppc > > $ make ARCH=powerpc lite5200_defconfig > $ make ARCH=ppc CROSS_COMPILE=powerpc-linux-gnu- uImage ARCH=ppc and ARCH=powerpc are completely different beasts. Forget that you even know about ARCH=ppc for this entire exercise. Cheers, g. -- Grant Likely, B.Sc., P.Eng. Secret Lab Technologies Ltd. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
