Re: [PATCH] powerpc/bootwrapper: Add documentation of boot wrappertargets

Stephen Neuendorffer wrote:

quoted

cuImage is for boards running an older U-Boot that does not understand
device trees.

Forgive my ignorance here, but what specifically does this imply?  As
far as I can tell, generally speaking, some of the board-specific
information is passed into the boot wrapper, which then stuffs it into
the device tree.

It implies that the binary is in uImage format, targets older u-boot (as 
opposed to some other bootloader entirely, which might be targeted with 
a dtbImage -- see adder875, for example), and has a device tree embedded.

quoted

uImage is for device-tree aware U-Boot versions

And this differs from above because it gets a device tree passed in,
which uboot has already stuffed correctly.

Yes.

quoted

dtbImage is used for boards that can take an ELF zImage, but still

need

quoted

a dtb provided.

simpleImage, not sure here.

So both of these are elfs...  but how do they differ?  Is it only in how
the right head.s file gets picked up?

Neither is necessarily an ELF.  The only simpleboot target I see is a 
flat binary, as are some of the dtbImage targets (adder875, ep88xc, 
ep405, etc).  simpleboot is more of a platform than an image type; it's 
a platform that assumes nothing about the firmware that loaded it, and 
gets all information from the embedded device tree.

-Scott