dtc/Documentation/dtc-paper.tex

17   Benjamin Herrenschmidt \texttt{<{benh}{@}{kernel.crashing.org}>}\\
42   We present a method for booting a \ppc{}\R Linux\R kernel on an
43   embedded machine.  To do this, we supply the kernel with a compact
51   the kernel.  The compiler can produce either a binary ``blob'' or an
56   booting a \texttt{ppc64} kernel without Open Firmware, and we plan
70 the Linux kernel uses OF calls to scan the device tree and transfer it
87 variety of hacks spread across the kernel to deal with the lack of
93 kernel image that supports multiple embedded machines.
103 the kernel boots, it takes over full control of the system from OF,
105 kernel, OF is no longer around for the second kernel to query.
111 the first thing the kernel runs is a small piece of code in
115 passed to the kernel proper, which eventually unflattens the tree into
117 \texttt{prom\_init.c} bootstrap and the rest of the kernel.
120 all or because \kexec has been used, the kernel instead starts
123 by part of the kernel from OF.  For \kexec, the userland
125 before invoking the new kernel.  For embedded systems the blob can
132 kernel that parses it and the bootloader that generates it.  In
136 \item \emph{relocatable}: the bootloader or kernel should be able to
217 the kernel must not use\footnote{Usually such ranges contain some data
219 kernel.}.  The list is represented as a simple array of (address,
255 properties that the kernel actually requires; the flattened tree
256 generally need not include devices that the kernel can probe itself.
259 for the PCI host bridges; the kernel will scan the buses thus
261 nodes for devices where the kernel needs extra information, though:
286 the kernel to build a complete representation of the system's
291 \phandle property.  When the kernel generates a flattened tree from
311 When the kernel unflattens the tree, it automatically generates a
372 way of communicating device tree information to the kernel.  It's
373 simple for the kernel to parse, and simple for bootloaders to
382 the tree before passing it to the booted kernel.
407   running kernel.
504   kernel to boot correctly.
508 rather than having to debug the results on an embedded kernel.  With
517 boot a \texttt{ppc64} kernel on an embedded system.  With the merge of
519 supported way to boot any merged \texttt{powerpc} kernel, 32-bit or
574 PowerPC kernel to Apple G5 machines and the Maple embedded board,
578 kernel.