arch/powerpc/bootwrapper.rst

17 others.  U-Boot is typically found on embedded PowerPC hardware, but there
28 			U-Boot (for versions that don't understand the device
29 			tree).  This image embeds a device tree blob inside
30 			the image.  The boot wrapper, kernel and device tree
31 			are all embedded inside the U-Boot uImage file format
33 			bd_info structure and loads the data into the device
37 			bd_info structure used in the old U-Boot interfaces,
38 			cuImages are platform specific.  Each specific
39 			U-Boot platform has a different platform init file
40 			which populates the embedded device tree with data
41 			from the platform specific bd_info file.  The platform
42 			specific cuImage platform init code can be found in
44 			cuImage init code for a specific board can be found in
47    dtbImage.%:		Similar to zImage, except device tree blob is embedded
53 			interface for passing a device tree directly.
55 			dtbImages have platform specific code for extracting
61 			specific initialization code is typically found in a
67 			a device tree blob.  This image is a flat binary that
71 			the embedded device tree for all information.
74 			on some ppc4xx hardware.  This image embeds a device
77    uImage:		Native image format used by U-Boot.  The uImage target
80 			requires a version of U-Boot that is able to pass
81 			a device tree to the kernel at boot.  If using an older
82 			version of U-Boot, then you need to use a cuImage
85    zImage.%:		Image format which does not embed a device tree.
87 			which are able to supply a device tree.  This image
88 			expects firmware to provide the device tree at boot.
93 Image types which embed a device tree blob (simpleImage, dtbImage, treeImage,
94 and cuImage) all generate the device tree blob from a file in the
95 arch/powerpc/boot/dts/ directory.  The Makefile selects the correct device
103 (arch/powerpc/boot/Makefile) by adding targets to the $image-y variable.  Look
107 ---------------
124 uses the -p (platform) argument as the main method of deciding which wrapper
126 middle of the script.  This is also the place where platform specific fixups
130 wrapper bits are very board specific and care should be taken to make sure