On Tue, Nov 8, 2011 at 2:10 AM, Simon Glass sjg@chromium.org wrote:
Can I assume that we have (or can have) a 'make uImage' target or similar in the kernel which can pack together:
- a compressed kernel (not zImage, I mean something that U-Boot can
decompress), with a rel_offset of 32KB
As explained by Nico, having the boot loader decompress the kernel is *bad*.
- a DTB
- a ramdisk
When testing various systems I already usually use a uImage with zImage+initramfs+DTB. This is frowned upon in some places but it works like this:
I attach the initramfs from a cpio file rather than from giving a file path list. This is rather popular in some embedded systems.
I configure it in like this with the config script (you can also use menuconfig or interactive config...):
scripts/config --file .config \ --enable BLK_DEV_INITRD \ --set-str INITRAMFS_SOURCE rootfs.cpio \ --enable INITRAMFS_COMPRESSION_GZIP \ --enable RD_GZIP
Since this was so convenient I made a patch to attach a DTB the same way which was floated on devicetree-discuss: http://www.mail-archive.com/devicetree-discuss@lists.ozlabs.org/msg07256.htm...
Nico didn't like that: http://www.mail-archive.com/devicetree-discuss@lists.ozlabs.org/msg06828.htm...
Alas, I'm still using that patch though. For systems where I cannot influence the boot loader it's easiest, since I just add another config snippet when I want to run them with DT:
scripts/config --file .config \ --enable USE_OF \ --enable ARM_APPENDED_DTB \ --enable ARM_ATAG_DTB_COMPAT \ --enable PROC_DEVICETREE \ --set-str ARM_APPENDED_DTB_FILE my-device-tree.dtb
Yours, Linus Walleij