Hello Stephan
On 11-08-14 18:53, Stephen Warren wrote:
On 08/10/2014 10:53 AM, Jeroen Hofstee wrote:
Hello Stephan,
On 10-08-14 05:11, Stephen Warren wrote:
The entire point of this series is to prevent distros from having to install bootloader-specific boot configuration files.
I fail to see why this is something to pursue. Since the distro knows the boot path, why should u-boot be polling all possible options?
This patch series allows U-Boot to find the OS and boot it. U-Boot is searching for some kind of boot configuration file.
This part of the process is the same as the BIOS searching all known possible boot devices for a partition marked bootable, and with a valid MBR. Or, it's the same as UEFI searching all possible boot devices for whatever config file or boot binary is mandated by UEFI.
Not in my mind, I am not against scanning the possible boot devices, on the contrary, I am trying to add booting the userland from usb instead of mmc for the rpi_b. The part I dislike is where it starts searching for specific files. The equivalent would be your BIOS actively searching for GRUB, LILO, Windows Boot manager etc. etc. and as a fallback try the MBR.
Also in this case the downstream provides information back, albeit tiny, it does indicate if it is bootable and a label to explain what is bootable.
U-Boot performs this searching before having any knowledge of the OS; there's no way for the OS to parameterize this search path, just like OSs don't configure a PC BIOS to search a specific HDD/floppy/CDROM for the MBR to boot.
Yup as said, this is the part I was looking for.
Once U-Boot locates extlinux.conf or boot.scr, that file encodes what files (kernel, DTB, initrd)
This is the part I get for free now with it, I don't really like it, since if we take this road it ends up looking for e.g. grub.conf, ubldr.conf, vxworks.conf etc etc.
I will have a look if I can tame the script, without modifying it nor u-boot, but I guess that is not possible since boot.scr comes after extlinux not before.
Regards, Jeroen