svn commit: r204431 - in vendor/dtc: . dist dist/Documentation
dist/libfdt dist/scripts dist/tests
Rafal Jaworowski
raj at FreeBSD.org
Sat Feb 27 20:19:06 UTC 2010
Author: raj
Date: Sat Feb 27 20:19:06 2010
New Revision: 204431
URL: http://svn.freebsd.org/changeset/base/204431
Log:
Initial import of the Device Tree Compiler (DTC) package v1.2.0.
Obtained from: git://git.jdl.com/software/dtc.git
Added:
vendor/dtc/
vendor/dtc/dist/
vendor/dtc/dist/Documentation/
vendor/dtc/dist/Documentation/dtc-paper.bib
vendor/dtc/dist/Documentation/dtc-paper.tex
vendor/dtc/dist/Documentation/dts-format.txt (contents, props changed)
vendor/dtc/dist/Documentation/manual.txt (contents, props changed)
vendor/dtc/dist/GPL
vendor/dtc/dist/Makefile (contents, props changed)
vendor/dtc/dist/Makefile.dtc (contents, props changed)
vendor/dtc/dist/README.license
vendor/dtc/dist/TODO
vendor/dtc/dist/checks.c (contents, props changed)
vendor/dtc/dist/convert-dtsv0-lexer.l
vendor/dtc/dist/data.c (contents, props changed)
vendor/dtc/dist/dtc-lexer.l
vendor/dtc/dist/dtc-parser.y
vendor/dtc/dist/dtc.c (contents, props changed)
vendor/dtc/dist/dtc.h (contents, props changed)
vendor/dtc/dist/flattree.c (contents, props changed)
vendor/dtc/dist/fstree.c (contents, props changed)
vendor/dtc/dist/ftdump.c (contents, props changed)
vendor/dtc/dist/libfdt/
vendor/dtc/dist/libfdt/Makefile.libfdt (contents, props changed)
vendor/dtc/dist/libfdt/TODO
vendor/dtc/dist/libfdt/fdt.c (contents, props changed)
vendor/dtc/dist/libfdt/fdt.h (contents, props changed)
vendor/dtc/dist/libfdt/fdt_ro.c (contents, props changed)
vendor/dtc/dist/libfdt/fdt_rw.c (contents, props changed)
vendor/dtc/dist/libfdt/fdt_strerror.c (contents, props changed)
vendor/dtc/dist/libfdt/fdt_sw.c (contents, props changed)
vendor/dtc/dist/libfdt/fdt_wip.c (contents, props changed)
vendor/dtc/dist/libfdt/libfdt.h (contents, props changed)
vendor/dtc/dist/libfdt/libfdt_env.h (contents, props changed)
vendor/dtc/dist/libfdt/libfdt_internal.h (contents, props changed)
vendor/dtc/dist/livetree.c (contents, props changed)
vendor/dtc/dist/scripts/
vendor/dtc/dist/scripts/setlocalversion (contents, props changed)
vendor/dtc/dist/srcpos.c (contents, props changed)
vendor/dtc/dist/srcpos.h (contents, props changed)
vendor/dtc/dist/tests/
vendor/dtc/dist/tests/Makefile.tests (contents, props changed)
vendor/dtc/dist/tests/add_subnode_with_nops.c (contents, props changed)
vendor/dtc/dist/tests/bad-empty-ranges.dts
vendor/dtc/dist/tests/bad-name-property.dts
vendor/dtc/dist/tests/bad-ncells.dts
vendor/dtc/dist/tests/bad-reg-ranges.dts
vendor/dtc/dist/tests/bad-string-props.dts
vendor/dtc/dist/tests/base01.asm
vendor/dtc/dist/tests/base01.cmd
vendor/dtc/dist/tests/base01.dts
vendor/dtc/dist/tests/base01.stderr
vendor/dtc/dist/tests/boot-cpuid.c (contents, props changed)
vendor/dtc/dist/tests/comments-cmp.dts
vendor/dtc/dist/tests/comments.dts
vendor/dtc/dist/tests/default-addr-size.dts
vendor/dtc/dist/tests/del_node.c (contents, props changed)
vendor/dtc/dist/tests/del_property.c (contents, props changed)
vendor/dtc/dist/tests/dtbs_equal_ordered.c (contents, props changed)
vendor/dtc/dist/tests/dtc-checkfails.sh (contents, props changed)
vendor/dtc/dist/tests/dtc-fatal.sh (contents, props changed)
vendor/dtc/dist/tests/dumptrees.c (contents, props changed)
vendor/dtc/dist/tests/dup-nodename.dts
vendor/dtc/dist/tests/dup-phandle.dts
vendor/dtc/dist/tests/dup-propname.dts
vendor/dtc/dist/tests/empty.dts
vendor/dtc/dist/tests/escapes.dts
vendor/dtc/dist/tests/find_property.c (contents, props changed)
vendor/dtc/dist/tests/get_mem_rsv.c (contents, props changed)
vendor/dtc/dist/tests/get_name.c (contents, props changed)
vendor/dtc/dist/tests/get_path.c (contents, props changed)
vendor/dtc/dist/tests/get_phandle.c (contents, props changed)
vendor/dtc/dist/tests/getprop.c (contents, props changed)
vendor/dtc/dist/tests/incbin.bin (contents, props changed)
vendor/dtc/dist/tests/incbin.c (contents, props changed)
vendor/dtc/dist/tests/incbin.dts
vendor/dtc/dist/tests/include0.dts
vendor/dtc/dist/tests/include1.dts
vendor/dtc/dist/tests/include2.dts
vendor/dtc/dist/tests/include3.dts
vendor/dtc/dist/tests/include4.dts
vendor/dtc/dist/tests/include5.dts
vendor/dtc/dist/tests/include6.dts
vendor/dtc/dist/tests/include7.dts
vendor/dtc/dist/tests/include8.dts
vendor/dtc/dist/tests/label01.dts
vendor/dtc/dist/tests/mangle-layout.c (contents, props changed)
vendor/dtc/dist/tests/mangle-layout.supp
vendor/dtc/dist/tests/minusone-phandle.dts
vendor/dtc/dist/tests/move_and_save.c (contents, props changed)
vendor/dtc/dist/tests/node_check_compatible.c (contents, props changed)
vendor/dtc/dist/tests/node_offset_by_compatible.c (contents, props changed)
vendor/dtc/dist/tests/node_offset_by_phandle.c (contents, props changed)
vendor/dtc/dist/tests/node_offset_by_prop_value.c (contents, props changed)
vendor/dtc/dist/tests/nonexist-label-ref.dts
vendor/dtc/dist/tests/nonexist-node-ref.dts
vendor/dtc/dist/tests/nop_node.c (contents, props changed)
vendor/dtc/dist/tests/nop_property.c (contents, props changed)
vendor/dtc/dist/tests/nopulate.c (contents, props changed)
vendor/dtc/dist/tests/notfound.c (contents, props changed)
vendor/dtc/dist/tests/obsolete-chosen-interrupt-controller.dts
vendor/dtc/dist/tests/open_pack.c (contents, props changed)
vendor/dtc/dist/tests/open_pack.supp
vendor/dtc/dist/tests/parent_offset.c (contents, props changed)
vendor/dtc/dist/tests/path-references.c (contents, props changed)
vendor/dtc/dist/tests/path-references.dts
vendor/dtc/dist/tests/path_offset.c (contents, props changed)
vendor/dtc/dist/tests/prop-after-subnode.dts
vendor/dtc/dist/tests/references.c (contents, props changed)
vendor/dtc/dist/tests/references.dts
vendor/dtc/dist/tests/references_dts0.dts
vendor/dtc/dist/tests/reg-ranges-root.dts
vendor/dtc/dist/tests/root_node.c (contents, props changed)
vendor/dtc/dist/tests/run_tests.sh (contents, props changed)
vendor/dtc/dist/tests/rw_tree1.c (contents, props changed)
vendor/dtc/dist/tests/set_name.c (contents, props changed)
vendor/dtc/dist/tests/setprop.c (contents, props changed)
vendor/dtc/dist/tests/setprop_inplace.c (contents, props changed)
vendor/dtc/dist/tests/string_escapes.c (contents, props changed)
vendor/dtc/dist/tests/subnode_offset.c (contents, props changed)
vendor/dtc/dist/tests/supernode_atdepth_offset.c (contents, props changed)
vendor/dtc/dist/tests/sw_tree1.c (contents, props changed)
vendor/dtc/dist/tests/test01.asm
vendor/dtc/dist/tests/test01.dts
vendor/dtc/dist/tests/test01.stderr
vendor/dtc/dist/tests/test_kernel_dts (contents, props changed)
vendor/dtc/dist/tests/test_tree1.dts
vendor/dtc/dist/tests/test_tree1_dts0.dts
vendor/dtc/dist/tests/testdata.h (contents, props changed)
vendor/dtc/dist/tests/tests.h (contents, props changed)
vendor/dtc/dist/tests/tests.sh (contents, props changed)
vendor/dtc/dist/tests/testutils.c (contents, props changed)
vendor/dtc/dist/tests/trees.S (contents, props changed)
vendor/dtc/dist/tests/truncated_property.c (contents, props changed)
vendor/dtc/dist/tests/zero-phandle.dts
vendor/dtc/dist/treesource.c (contents, props changed)
Added: vendor/dtc/dist/Documentation/dtc-paper.bib
==============================================================================
--- /dev/null 00:00:00 1970 (empty, because file is newly added)
+++ vendor/dtc/dist/Documentation/dtc-paper.bib Sat Feb 27 20:19:06 2010 (r204431)
@@ -0,0 +1,43 @@
+ at STRING{pub-IEEE = "IEEE Computer Society"}
+ at STRING{pub-IEEE:adr = "345 E. 47th St, New York, NY 10017, USA"}
+
+ at BOOK{IEEE1275,
+ key = "IEEE1275",
+ title = "{IEEE} {S}tandard for {B}oot ({I}nitialization {C}onfiguration) {F}irmware: {C}ore {R}equirements and {P}ractices",
+ publisher = pub-IEEE,
+ address = pub-IEEE:adr,
+ series = "IEEE Std 1275-1994",
+ year = 1994,
+}
+
+ at BOOK{IEEE1275-pci,
+ key = "IEEE1275-pci",
+ title = "{PCI} {B}us {B}inding to: {IEEE} {S}td 1275-1994 {S}tandard for {B}oot ({I}nitialization {C}onfiguration) {F}irmware",
+ publisher = pub-IEEE,
+ address = pub-IEEE:adr,
+ note = "Revision 2.1",
+ year = 1998,
+}
+
+ at MISC{noof1,
+ author = "Benjamin Herrenschmidt",
+ title = "Booting the {L}inux/ppc kernel without {O}pen {F}irmware",
+ month = may,
+ year = 2005,
+ note = "v0.1, \url{http://ozlabs.org/pipermail/linuxppc64-dev/2005-May/004073.html}",
+}
+
+ at MISC{noof5,
+ author = "Benjamin Herrenschmidt",
+ title = "Booting the {L}inux/ppc kernel without {O}pen {F}irmware",
+ month = nov,
+ year = 2005,
+ note = "v0.5, \url{http://ozlabs.org/pipermail/linuxppc64-dev/2005-December/006994.html}",
+}
+
+ at MISC{dtcgit,
+ author = "David Gibson et al.",
+ title = "\dtc{}",
+ howpublished = "git tree",
+ note = "\url{http://ozlabs.org/~dgibson/dtc/dtc.git}",
+}
Added: vendor/dtc/dist/Documentation/dtc-paper.tex
==============================================================================
--- /dev/null 00:00:00 1970 (empty, because file is newly added)
+++ vendor/dtc/dist/Documentation/dtc-paper.tex Sat Feb 27 20:19:06 2010 (r204431)
@@ -0,0 +1,597 @@
+\documentclass[a4paper,twocolumn]{article}
+
+\usepackage{abstract}
+\usepackage{xspace}
+\usepackage{amssymb}
+\usepackage{latexsym}
+\usepackage{tabularx}
+\usepackage[T1]{fontenc}
+\usepackage{calc}
+\usepackage{listings}
+\usepackage{color}
+\usepackage{url}
+
+\title{Device trees everywhere}
+
+\author{David Gibson \texttt{<{dwg}{@}{au1.ibm.com}>}\\
+ Benjamin Herrenschmidt \texttt{<{benh}{@}{kernel.crashing.org}>}\\
+ \emph{OzLabs, IBM Linux Technology Center}}
+
+\newcommand{\R}{\textsuperscript{\textregistered}\xspace}
+\newcommand{\tm}{\textsuperscript{\texttrademark}\xspace}
+\newcommand{\tge}{$\geqslant$}
+%\newcommand{\ditto}{\textquotedbl\xspace}
+
+\newcommand{\fixme}[1]{$\bigstar$\emph{\textbf{\large #1}}$\bigstar$\xspace}
+
+\newcommand{\ppc}{\mbox{PowerPC}\xspace}
+\newcommand{\of}{Open Firmware\xspace}
+\newcommand{\benh}{Ben Herrenschmidt\xspace}
+\newcommand{\kexec}{\texttt{kexec()}\xspace}
+\newcommand{\dtbeginnode}{\texttt{OF\_DT\_BEGIN\_NODE\xspace}}
+\newcommand{\dtendnode}{\texttt{OF\_DT\_END\_NODE\xspace}}
+\newcommand{\dtprop}{\texttt{OF\_DT\_PROP\xspace}}
+\newcommand{\dtend}{\texttt{OF\_DT\_END\xspace}}
+\newcommand{\dtc}{\texttt{dtc}\xspace}
+\newcommand{\phandle}{\texttt{linux,phandle}\xspace}
+\begin{document}
+
+\maketitle
+
+\begin{abstract}
+ We present a method for booting a \ppc{}\R Linux\R kernel on an
+ embedded machine. To do this, we supply the kernel with a compact
+ flattened-tree representation of the system's hardware based on the
+ device tree supplied by Open Firmware on IBM\R servers and Apple\R
+ Power Macintosh\R machines.
+
+ The ``blob'' representing the device tree can be created using \dtc
+ --- the Device Tree Compiler --- that turns a simple text
+ representation of the tree into the compact representation used by
+ the kernel. The compiler can produce either a binary ``blob'' or an
+ assembler file ready to be built into a firmware or bootwrapper
+ image.
+
+ This flattened-tree approach is now the only supported method of
+ booting a \texttt{ppc64} kernel without Open Firmware, and we plan
+ to make it the only supported method for all \texttt{powerpc}
+ kernels in the future.
+\end{abstract}
+
+\section{Introduction}
+
+\subsection{OF and the device tree}
+
+Historically, ``everyday'' \ppc machines have booted with the help of
+\of (OF), a firmware environment defined by IEEE1275 \cite{IEEE1275}.
+Among other boot-time services, OF maintains a device tree that
+describes all of the system's hardware devices and how they're
+connected. During boot, before taking control of memory management,
+the Linux kernel uses OF calls to scan the device tree and transfer it
+to an internal representation that is used at run time to look up
+various device information.
+
+The device tree consists of nodes representing devices or
+buses\footnote{Well, mostly. There are a few special exceptions.}.
+Each node contains \emph{properties}, name--value pairs that give
+information about the device. The values are arbitrary byte strings,
+and for some properties, they contain tables or other structured
+information.
+
+\subsection{The bad old days}
+
+Embedded systems, by contrast, usually have a minimal firmware that
+might supply a few vital system parameters (size of RAM and the like),
+but nothing as detailed or complete as the OF device tree. This has
+meant that the various 32-bit \ppc embedded ports have required a
+variety of hacks spread across the kernel to deal with the lack of
+device tree. These vary from specialised boot wrappers to parse
+parameters (which are at least reasonably localised) to
+CONFIG-dependent hacks in drivers to override normal probe logic with
+hardcoded addresses for a particular board. As well as being ugly of
+itself, such CONFIG-dependent hacks make it hard to build a single
+kernel image that supports multiple embedded machines.
+
+Until relatively recently, the only 64-bit \ppc machines without OF
+were legacy (pre-POWER5\R) iSeries\R machines. iSeries machines often
+only have virtual IO devices, which makes it quite simple to work
+around the lack of a device tree. Even so, the lack means the iSeries
+boot sequence must be quite different from the pSeries or Macintosh,
+which is not ideal.
+
+The device tree also presents a problem for implementing \kexec. When
+the kernel boots, it takes over full control of the system from OF,
+even re-using OF's memory. So, when \kexec comes to boot another
+kernel, OF is no longer around for the second kernel to query.
+
+\section{The Flattened Tree}
+
+In May 2005 \benh implemented a new approach to handling the device
+tree that addresses all these problems. When booting on OF systems,
+the first thing the kernel runs is a small piece of code in
+\texttt{prom\_init.c}, which executes in the context of OF. This code
+walks the device tree using OF calls, and transcribes it into a
+compact, flattened format. The resulting device tree ``blob'' is then
+passed to the kernel proper, which eventually unflattens the tree into
+its runtime form. This blob is the only data communicated between the
+\texttt{prom\_init.c} bootstrap and the rest of the kernel.
+
+When OF isn't available, either because the machine doesn't have it at
+all or because \kexec has been used, the kernel instead starts
+directly from the entry point taking a flattened device tree. The
+device tree blob must be passed in from outside, rather than generated
+by part of the kernel from OF. For \kexec, the userland
+\texttt{kexec} tools build the blob from the runtime device tree
+before invoking the new kernel. For embedded systems the blob can
+come either from the embedded bootloader, or from a specialised
+version of the \texttt{zImage} wrapper for the system in question.
+
+\subsection{Properties of the flattened tree}
+
+The flattened tree format should be easy to handle, both for the
+kernel that parses it and the bootloader that generates it. In
+particular, the following properties are desirable:
+
+\begin{itemize}
+\item \emph{relocatable}: the bootloader or kernel should be able to
+ move the blob around as a whole, without needing to parse or adjust
+ its internals. In practice that means we must not use pointers
+ within the blob.
+\item \emph{insert and delete}: sometimes the bootloader might want to
+ make tweaks to the flattened tree, such as deleting or inserting a
+ node (or whole subtree). It should be possible to do this without
+ having to effectively regenerate the whole flattened tree. In
+ practice this means limiting the use of internal offsets in the blob
+ that need recalculation if a section is inserted or removed with
+ \texttt{memmove()}.
+\item \emph{compact}: embedded systems are frequently short of
+ resources, particularly RAM and flash memory space. Thus, the tree
+ representation should be kept as small as conveniently possible.
+\end{itemize}
+
+\subsection{Format of the device tree blob}
+\label{sec:format}
+
+\begin{figure}[htb!]
+ \centering
+ \footnotesize
+ \begin{tabular}{r|c|l}
+ \multicolumn{1}{r}{\textbf{Offset}}& \multicolumn{1}{c}{\textbf{Contents}} \\\cline{2-2}
+ \texttt{0x00} & \texttt{0xd00dfeed} & magic number \\\cline{2-2}
+ \texttt{0x04} & \emph{totalsize} \\\cline{2-2}
+ \texttt{0x08} & \emph{off\_struct} & \\\cline{2-2}
+ \texttt{0x0C} & \emph{off\_strs} & \\\cline{2-2}
+ \texttt{0x10} & \emph{off\_rsvmap} & \\\cline{2-2}
+ \texttt{0x14} & \emph{version} \\\cline{2-2}
+ \texttt{0x18} & \emph{last\_comp\_ver} & \\\cline{2-2}
+ \texttt{0x1C} & \emph{boot\_cpu\_id} & \tge v2 only\\\cline{2-2}
+ \texttt{0x20} & \emph{size\_strs} & \tge v3 only\\\cline{2-2}
+ \multicolumn{1}{r}{\vdots} & \multicolumn{1}{c}{\vdots} & \\\cline{2-2}
+ \emph{off\_rsvmap} & \emph{address0} & memory reserve \\
+ + \texttt{0x04} & ...& table \\\cline{2-2}
+ + \texttt{0x08} & \emph{len0} & \\
+ + \texttt{0x0C} & ...& \\\cline{2-2}
+ \vdots & \multicolumn{1}{c|}{\vdots} & \\\cline{2-2}
+ & \texttt{0x00000000}- & end marker\\
+ & \texttt{00000000} & \\\cline{2-2}
+ & \texttt{0x00000000}- & \\
+ & \texttt{00000000} & \\\cline{2-2}
+ \multicolumn{1}{r}{\vdots} & \multicolumn{1}{c}{\vdots} & \\\cline{2-2}
+ \emph{off\_strs} & \texttt{'n' 'a' 'm' 'e'} & strings block \\
+ + \texttt{0x04} & \texttt{~0~ 'm' 'o' 'd'} & \\
+ + \texttt{0x08} & \texttt{'e' 'l' ~0~ \makebox[\widthof{~~~}]{\textrm{...}}} & \\
+ \vdots & \multicolumn{1}{c|}{\vdots} & \\\cline{2-2}
+ \multicolumn{1}{r}{+ \emph{size\_strs}} \\
+ \multicolumn{1}{r}{\vdots} & \multicolumn{1}{c}{\vdots} & \\\cline{2-2}
+ \emph{off\_struct} & \dtbeginnode & structure block \\\cline{2-2}
+ + \texttt{0x04} & \texttt{'/' ~0~ ~0~ ~0~} & root node\\\cline{2-2}
+ + \texttt{0x08} & \dtprop & \\\cline{2-2}
+ + \texttt{0x0C} & \texttt{0x00000005} & ``\texttt{model}''\\\cline{2-2}
+ + \texttt{0x10} & \texttt{0x00000008} & \\\cline{2-2}
+ + \texttt{0x14} & \texttt{'M' 'y' 'B' 'o'} & \\
+ + \texttt{0x18} & \texttt{'a' 'r' 'd' ~0~} & \\\cline{2-2}
+ \vdots & \multicolumn{1}{c|}{\vdots} & \\\cline{2-2}
+ & \texttt{\dtendnode} \\\cline{2-2}
+ & \texttt{\dtend} \\\cline{2-2}
+ \multicolumn{1}{r}{\vdots} & \multicolumn{1}{c}{\vdots} & \\\cline{2-2}
+ \multicolumn{1}{r}{\emph{totalsize}} \\
+ \end{tabular}
+ \caption{Device tree blob layout}
+ \label{fig:blob-layout}
+\end{figure}
+
+The format for the blob we devised, was first described on the
+\texttt{linuxppc64-dev} mailing list in \cite{noof1}. The format has
+since evolved through various revisions, and the current version is
+included as part of the \dtc (see \S\ref{sec:dtc}) git tree,
+\cite{dtcgit}.
+
+Figure \ref{fig:blob-layout} shows the layout of the blob of data
+containing the device tree. It has three sections of variable size:
+the \emph{memory reserve table}, the \emph{structure block} and the
+\emph{strings block}. A small header gives the blob's size and
+version and the locations of the three sections, plus a handful of
+vital parameters used during early boot.
+
+The memory reserve map section gives a list of regions of memory that
+the kernel must not use\footnote{Usually such ranges contain some data
+structure initialised by the firmware that must be preserved by the
+kernel.}. The list is represented as a simple array of (address,
+size) pairs of 64 bit values, terminated by a zero size entry. The
+strings block is similarly simple, consisting of a number of
+null-terminated strings appended together, which are referenced from
+the structure block as described below.
+
+The structure block contains the device tree proper. Each node is
+introduced with a 32-bit \dtbeginnode tag, followed by the node's name
+as a null-terminated string, padded to a 32-bit boundary. Then
+follows all of the properties of the node, each introduced with a
+\dtprop tag, then all of the node's subnodes, each introduced with
+their own \dtbeginnode tag. The node ends with an \dtendnode tag, and
+after the \dtendnode for the root node is an \dtend tag, indicating
+the end of the whole tree\footnote{This is redundant, but included for
+ease of parsing.}. The structure block starts with the \dtbeginnode
+introducing the description of the root node (named \texttt{/}).
+
+Each property, after the \dtprop, has a 32-bit value giving an offset
+from the beginning of the strings block at which the property name is
+stored. Because it's common for many nodes to have properties with
+the same name, this approach can substantially reduce the total size
+of the blob. The name offset is followed by the length of the
+property value (as a 32-bit value) and then the data itself padded to
+a 32-bit boundary.
+
+\subsection{Contents of the tree}
+\label{sec:treecontents}
+
+Having seen how to represent the device tree structure as a flattened
+blob, what actually goes into the tree? The short answer is ``the
+same as an OF tree''. On OF systems, the flattened tree is
+transcribed directly from the OF device tree, so for simplicity we
+also use OF conventions for the tree on other systems.
+
+In many cases a flat tree can be simpler than a typical OF provided
+device tree. The flattened tree need only provide those nodes and
+properties that the kernel actually requires; the flattened tree
+generally need not include devices that the kernel can probe itself.
+For example, an OF device tree would normally include nodes for each
+PCI device on the system. A flattened tree need only include nodes
+for the PCI host bridges; the kernel will scan the buses thus
+described to find the subsidiary devices. The device tree can include
+nodes for devices where the kernel needs extra information, though:
+for example, for ISA devices on a subsidiary PCI/ISA bridge, or for
+devices with unusual interrupt routing.
+
+Where they exist, we follow the IEEE1275 bindings that specify how to
+describe various buses in the device tree (for example,
+\cite{IEEE1275-pci} describe how to represent PCI devices). The
+standard has not been updated for a long time, however, and lacks
+bindings for many modern buses and devices. In particular, embedded
+specific devices such as the various System-on-Chip buses are not
+covered. We intend to create new bindings for such buses, in keeping
+with the general conventions of IEEE1275 (a simple such binding for a
+System-on-Chip bus was included in \cite{noof5} a revision of
+\cite{noof1}).
+
+One complication arises for representing ``phandles'' in the flattened
+tree. In OF, each node in the tree has an associated phandle, a
+32-bit integer that uniquely identifies the node\footnote{In practice
+usually implemented as a pointer or offset within OF memory.}. This
+handle is used by the various OF calls to query and traverse the tree.
+Sometimes phandles are also used within the tree to refer to other
+nodes in the tree. For example, devices that produce interrupts
+generally have an \texttt{interrupt-parent} property giving the
+phandle of the interrupt controller that handles interrupts from this
+device. Parsing these and other interrupt related properties allows
+the kernel to build a complete representation of the system's
+interrupt tree, which can be quite different from the tree of bus
+connections.
+
+In the flattened tree, a node's phandle is represented by a special
+\phandle property. When the kernel generates a flattened tree from
+OF, it adds a \phandle property to each node, containing the phandle
+retrieved from OF. When the tree is generated without OF, however,
+only nodes that are actually referred to by phandle need to have this
+property.
+
+Another complication arises because nodes in an OF tree have two
+names. First they have the ``unit name'', which is how the node is
+referred to in an OF path. The unit name generally consists of a
+device type followed by an \texttt{@} followed by a \emph{unit
+address}. For example \texttt{/memory at 0} is the full path of a memory
+node at address 0, \texttt{/ht at 0,f2000000/pci at 1} is the path of a PCI
+bus node, which is under a HyperTransport\tm bus node. The form of
+the unit address is bus dependent, but is generally derived from the
+node's \texttt{reg} property. In addition, nodes have a property,
+\texttt{name}, whose value is usually equal to the first path of the
+unit name. For example, the nodes in the previous example would have
+\texttt{name} properties equal to \texttt{memory} and \texttt{pci},
+respectively. To save space in the blob, the current version of the
+flattened tree format only requires the unit names to be present.
+When the kernel unflattens the tree, it automatically generates a
+\texttt{name} property from the node's path name.
+
+\section{The Device Tree Compiler}
+\label{sec:dtc}
+
+\begin{figure}[htb!]
+ \centering
+ \begin{lstlisting}[frame=single,basicstyle=\footnotesize\ttfamily,
+ tabsize=3,numbers=left,xleftmargin=2em]
+/memreserve/ 0x20000000-0x21FFFFFF;
+
+/ {
+ model = "MyBoard";
+ compatible = "MyBoardFamily";
+ #address-cells = <2>;
+ #size-cells = <2>;
+
+ cpus {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ PowerPC,970 at 0 {
+ device_type = "cpu";
+ reg = <0>;
+ clock-frequency = <5f5e1000>;
+ timebase-frequency = <1FCA055>;
+ linux,boot-cpu;
+ i-cache-size = <10000>;
+ d-cache-size = <8000>;
+ };
+ };
+
+ memory at 0 {
+ device_type = "memory";
+ memreg: reg = <00000000 00000000
+ 00000000 20000000>;
+ };
+
+ mpic at 0x3fffdd08400 {
+ /* Interrupt controller */
+ /* ... */
+ };
+
+ pci at 40000000000000 {
+ /* PCI host bridge */
+ /* ... */
+ };
+
+ chosen {
+ bootargs = "root=/dev/sda2";
+ linux,platform = <00000600>;
+ interrupt-controller =
+ < &/mpic at 0x3fffdd08400 >;
+ };
+};
+\end{lstlisting}
+ \caption{Example \dtc source}
+ \label{fig:dts}
+\end{figure}
+
+As we've seen, the flattened device tree format provides a convenient
+way of communicating device tree information to the kernel. It's
+simple for the kernel to parse, and simple for bootloaders to
+manipulate. On OF systems, it's easy to generate the flattened tree
+by walking the OF maintained tree. However, for embedded systems, the
+flattened tree must be generated from scratch.
+
+Embedded bootloaders are generally built for a particular board. So,
+it's usually possible to build the device tree blob at compile time
+and include it in the bootloader image. For minor revisions of the
+board, the bootloader can contain code to make the necessary tweaks to
+the tree before passing it to the booted kernel.
+
+The device trees for embedded boards are usually quite simple, and
+it's possible to hand construct the necessary blob by hand, but doing
+so is tedious. The ``device tree compiler'', \dtc{}\footnote{\dtc can
+be obtained from \cite{dtcgit}.}, is designed to make creating device
+tree blobs easier by converting a text representation of the tree
+into the necessary blob.
+
+\subsection{Input and output formats}
+
+As well as the normal mode of compiling a device tree blob from text
+source, \dtc can convert a device tree between a number of
+representations. It can take its input in one of three different
+formats:
+\begin{itemize}
+\item source, the normal case. The device tree is described in a text
+ form, described in \S\ref{sec:dts}.
+\item blob (\texttt{dtb}), the flattened tree format described in
+ \S\ref{sec:format}. This mode is useful for checking a pre-existing
+ device tree blob.
+\item filesystem (\texttt{fs}), input is a directory tree in the
+ layout of \texttt{/proc/device-tree} (roughly, a directory for each
+ node in the device tree, a file for each property). This is useful
+ for building a blob for the device tree in use by the currently
+ running kernel.
+\end{itemize}
+
+In addition, \dtc can output the tree in one of three different
+formats:
+\begin{itemize}
+\item blob (\texttt{dtb}), as in \S\ref{sec:format}. The most
+ straightforward use of \dtc is to compile from ``source'' to
+ ``blob'' format.
+\item source (\texttt{dts}), as in \S\ref{sec:dts}. If used with blob
+ input, this allows \dtc to act as a ``decompiler''.
+\item assembler source (\texttt{asm}). \dtc can produce an assembler
+ file, which will assemble into a \texttt{.o} file containing the
+ device tree blob, with symbols giving the beginning of the blob and
+ its various subsections. This can then be linked directly into a
+ bootloader or firmware image.
+\end{itemize}
+
+For maximum applicability, \dtc can both read and write any of the
+existing revisions of the blob format. When reading, \dtc takes the
+version from the blob header, and when writing it takes a command line
+option specifying the desired version. It automatically makes any
+necessary adjustments to the tree that are necessary for the specified
+version. For example, formats before 0x10 require each node to have
+an explicit \texttt{name} property. When \dtc creates such a blob, it
+will automatically generate \texttt{name} properties from the unit
+names.
+
+\subsection{Source format}
+\label{sec:dts}
+
+The ``source'' format for \dtc is a text description of the device
+tree in a vaguely C-like form. Figure \ref{fig:dts} shows an
+example. The file starts with \texttt{/memreserve/} directives, which
+gives address ranges to add to the output blob's memory reserve table,
+then the device tree proper is described.
+
+Nodes of the tree are introduced with the node name, followed by a
+\texttt{\{} ... \texttt{\};} block containing the node's properties
+and subnodes. Properties are given as just {\emph{name} \texttt{=}
+ \emph{value}\texttt{;}}. The property values can be given in any
+of three forms:
+\begin{itemize}
+\item \emph{string} (for example, \texttt{"MyBoard"}). The property
+ value is the given string, including terminating NULL. C-style
+ escapes (\verb+\t+, \verb+\n+, \verb+\0+ and so forth) are allowed.
+\item \emph{cells} (for example, \texttt{<0 8000 f0000000>}). The
+ property value is made up of a list of 32-bit ``cells'', each given
+ as a hex value.
+\item \emph{bytestring} (for example, \texttt{[1234abcdef]}). The
+ property value is given as a hex bytestring.
+\end{itemize}
+
+Cell properties can also contain \emph{references}. Instead of a hex
+number, the source can give an ampersand (\texttt{\&}) followed by the
+full path to some node in the tree. For example, in Figure
+\ref{fig:dts}, the \texttt{/chosen} node has an
+\texttt{interrupt-controller} property referring to the interrupt
+controller described by the node \texttt{/mpic at 0x3fffdd08400}. In the
+output tree, the value of the referenced node's phandle is included in
+the property. If that node doesn't have an explicit phandle property,
+\dtc will automatically create a unique phandle for it. This approach
+makes it easy to create interrupt trees without having to explicitly
+assign and remember phandles for the various interrupt controller
+nodes.
+
+The \dtc source can also include ``labels'', which are placed on a
+particular node or property. For example, Figure \ref{fig:dts} has a
+label ``\texttt{memreg}'' on the \texttt{reg} property of the node
+\texttt{/memory at 0}. When using assembler output, corresponding labels
+in the output are generated, which will assemble into symbols
+addressing the part of the blob with the node or property in question.
+This is useful for the common case where an embedded board has an
+essentially fixed device tree with a few variable properties, such as
+the size of memory. The bootloader for such a board can have a device
+tree linked in, including a symbol referring to the right place in the
+blob to update the parameter with the correct value determined at
+runtime.
+
+\subsection{Tree checking}
+
+Between reading in the device tree and writing it out in the new
+format, \dtc performs a number of checks on the tree:
+\begin{itemize}
+\item \emph{syntactic structure}: \dtc checks that node and property
+ names contain only allowed characters and meet length restrictions.
+ It checks that a node does not have multiple properties or subnodes
+ with the same name.
+\item \emph{semantic structure}: In some cases, \dtc checks that
+ properties whose contents are defined by convention have appropriate
+ values. For example, it checks that \texttt{reg} properties have a
+ length that makes sense given the address forms specified by the
+ \texttt{\#address-cells} and \texttt{\#size-cells} properties. It
+ checks that properties such as \texttt{interrupt-parent} contain a
+ valid phandle.
+\item \emph{Linux requirements}: \dtc checks that the device tree
+ contains those nodes and properties that are required by the Linux
+ kernel to boot correctly.
+\end{itemize}
+
+These checks are useful to catch simple problems with the device tree,
+rather than having to debug the results on an embedded kernel. With
+the blob input mode, it can also be used for diagnosing problems with
+an existing blob.
+
+\section{Future Work}
+
+\subsection{Board ports}
+
+The flattened device tree has always been the only supported way to
+boot a \texttt{ppc64} kernel on an embedded system. With the merge of
+\texttt{ppc32} and \texttt{ppc64} code it has also become the only
+supported way to boot any merged \texttt{powerpc} kernel, 32-bit or
+64-bit. In fact, the old \texttt{ppc} architecture exists mainly just
+to support the old ppc32 embedded ports that have not been migrated
+to the flattened device tree approach. We plan to remove the
+\texttt{ppc} architecture eventually, which will mean porting all the
+various embedded boards to use the flattened device tree.
+
+\subsection{\dtc features}
+
+While it is already quite usable, there are a number of extra features
+that \dtc could include to make creating device trees more convenient:
+\begin{itemize}
+\item \emph{better tree checking}: Although \dtc already performs a
+ number of checks on the device tree, they are rather haphazard. In
+ many cases \dtc will give up after detecting a minor error early and
+ won't pick up more interesting errors later on. There is a
+ \texttt{-f} parameter that forces \dtc to generate an output tree
+ even if there are errors. At present, this needs to be used more
+ often than one might hope, because \dtc is bad at deciding which
+ errors should really be fatal, and which rate mere warnings.
+\item \emph{binary include}: Occasionally, it is useful for the device
+ tree to incorporate as a property a block of binary data for some
+ board-specific purpose. For example, many of Apple's device trees
+ incorporate bytecode drivers for certain platform devices. \dtc's
+ source format ought to allow this by letting a property's value be
+ read directly from a binary file.
+\item \emph{macros}: it might be useful for \dtc to implement some
+ sort of macros so that a tree containing a number of similar devices
+ (for example, multiple identical ethernet controllers or PCI buses)
+ can be written more quickly. At present, this can be accomplished
+ in part by running the source file through CPP before compiling with
+ \dtc. It's not clear whether ``native'' support for macros would be
+ more useful.
+\end{itemize}
+
+\bibliographystyle{amsplain}
+\bibliography{dtc-paper}
+
+\section*{About the authors}
+
+David Gibson has been a member of the IBM Linux Technology Center,
+working from Canberra, Australia, since 2001. Recently he has worked
+on Linux hugepage support and performance counter support for ppc64,
+as well as the device tree compiler. In the past, he has worked on
+bringup for various ppc and ppc64 embedded systems, the orinoco
+wireless driver, ramfs, and a userspace checkpointing system
+(\texttt{esky}).
+
+Benjamin Herrenschmidt was a MacOS developer for about 10 years, but
+ultimately saw the light and installed Linux on his Apple PowerPC
+machine. After writing a bootloader, BootX, for it in 1998, he
+started contributing to the PowerPC Linux port in various areas,
+mostly around the support for Apple machines. He became official
+PowerMac maintainer in 2001. In 2003, he joined the IBM Linux
+Technology Center in Canberra, Australia, where he ported the 64 bit
+PowerPC kernel to Apple G5 machines and the Maple embedded board,
+among others things. He's a member of the ppc64 development ``team''
+and one of his current goals is to make the integration of embedded
+platforms smoother and more maintainable than in the 32-bit PowerPC
+kernel.
+
+\section*{Legal Statement}
+
+This work represents the view of the author and does not necessarily
+represent the view of IBM.
+
+IBM, \ppc, \ppc Architecture, POWER5, pSeries and iSeries are
+trademarks or registered trademarks of International Business Machines
+Corporation in the United States and/or other countries.
+
+Apple and Power Macintosh are a registered trademarks of Apple
+Computer Inc. in the United States, other countries, or both.
+
+Linux is a registered trademark of Linus Torvalds.
+
+Other company, product, and service names may be trademarks or service
+marks of others.
+
+\end{document}
Added: vendor/dtc/dist/Documentation/dts-format.txt
==============================================================================
--- /dev/null 00:00:00 1970 (empty, because file is newly added)
+++ vendor/dtc/dist/Documentation/dts-format.txt Sat Feb 27 20:19:06 2010 (r204431)
@@ -0,0 +1,110 @@
+Device Tree Source Format (version 1)
+=====================================
+
+The Device Tree Source (DTS) format is a textual representation of a
+device tree in a form that can be processed by dtc into a binary
+device tree in the form expected by the kernel. The description below
+is not a formal syntax definition of DTS, but describes the basic
+constructs used to represent device trees.
+
+Node and property definitions
+-----------------------------
+
+Device tree nodes are defined with a node name and unit address with
+braces marking the start and end of the node definition. They may be
+preceded by a label.
+
+ [label:] node-name[@unit-address] {
+ [properties definitions]
+ [child nodes]
+ }
+
+Nodes may contain property definitions and/or child node
+definitions. If both are present, properties must come before child
+nodes.
+
+Property definitions are name value pairs in the form:
+ [label:] property-name = value;
+except for properties with empty (zero length) value which have the
+form:
+ [label:] property-name;
+
+Property values may be defined as an array of 32-bit integer cells, as
+NUL-terminated strings, as bytestrings or a combination of these.
+
+* Arrays of cells are represented by angle brackets surrounding a
+ space separated list of C-style integers
+
+ e.g. interrupts = <17 0xc>;
+
+* A 64-bit value is represented with two 32-bit cells.
+
+ e.g. clock-frequency = <0x00000001 0x00000000>;
+
+* A NUL-terminated string value is represented using double quotes
+ (the property value is considered to include the terminating NUL
+ character).
+
+ e.g. compatible = "simple-bus";
+
+* A bytestring is enclosed in square brackets [] with each byte
+ represented by two hexadecimal digits. Spaces between each byte are
+ optional.
+
+ e.g. local-mac-address = [00 00 12 34 56 78]; or equivalently
+ local-mac-address = [000012345678];
+
+* Values may have several comma-separated components, which are
+ concatenated together.
+ e.g. compatible = "ns16550", "ns8250";
+ example = <0xf00f0000 19>, "a strange property format";
+
+* In a cell array a reference to another node will be expanded to that
+ node's phandle. References may by '&' followed by a node's label:
+ e.g. interrupt-parent = < &mpic >;
+ or they may be '&' followed by a node's full path in braces:
+ e.g. interrupt-parent = < &{/soc/interrupt-controller at 40000} >;
+
+* Outside a cell array, a reference to another node will be expanded
+ to that node's full path.
+ e.g. ethernet0 = &EMAC0;
+
+* Labels may also appear before or after any component of a property
+ value, or between cells of a cell array, or between bytes of a
+ bytestring.
+ e.g. reg = reglabel: <0 sizelabel: 0x1000000>;
+ e.g. prop = [ab cd ef byte4: 00 ff fe];
+ e.g. str = start: "string value" end: ;
+
+
+File layout
+-----------
+
+Version 1 DTS files have the overall layout:
+ /dts-v1/;
+
+ [memory reservations]
+
+ / {
+ [property definitions]
+ [child nodes]
+ };
+
+* The "/dts-v1/;" must be present to identify the file as a version 1
+ DTS (dts files without this tag will be treated by dtc as being in
+ the obsolete "version 0", which uses a different format for integers
+ amongst other small but incompatible changes).
+
+* Memory reservations define an entry for the device tree blob's
+ memory reservation table. They have the form:
+ e.g. /memreserve/ <address> <length>;
+ Where <address> and <length> are 64-bit C-style integers.
+
+* The / { ... }; section defines the root node of the device tree.
+
+* C style (/* ... */) and C++ style (// ...) comments are supported.
+
+
+
+ -- David Gibson <david at gibson.dropbear.id.au>
+ -- Yoder Stuart <stuart.yoder at freescale.com>
Added: vendor/dtc/dist/Documentation/manual.txt
==============================================================================
--- /dev/null 00:00:00 1970 (empty, because file is newly added)
+++ vendor/dtc/dist/Documentation/manual.txt Sat Feb 27 20:19:06 2010 (r204431)
@@ -0,0 +1,618 @@
+Device Tree Compiler Manual
+===========================
+
+I - "dtc", the device tree compiler
+ 1) Obtaining Sources
+ 2) Description
+ 3) Command Line
+ 4) Source File
+ 4.1) Overview
+ 4.2) Properties
+ 4.3) Labels and References
+
+II - The DT block format
+ 1) Header
+ 2) Device tree generalities
+ 3) Device tree "structure" block
+ 4) Device tree "strings" block
+
+
+III - libfdt
+
+
+I - "dtc", the device tree compiler
+===================================
+
+1) Sources
+
+Source code for the Device Tree Compiler can be found at jdl.com.
+The gitweb interface is:
+
+ http://www.jdl.com/git_repos/
+
+The repository is here:
+
+ git://www.jdl.com/software/dtc.git
+ http://www.jdl.com/software/dtc.git
+
+Tarballs of the 1.0.0 and latest releases are here:
+
+ http://www.jdl.com/software/dtc-1.0.0.tgz
+ http://www.jdl.com/software/dtc-latest.tgz
+
+
+2) Description
+
+The Device Tree Compiler, dtc, takes as input a device-tree in
+a given format and outputs a device-tree in another format.
+Typically, the input format is "dts", a human readable source
+format, and creates a "dtb", or binary format as output.
+
+The currently supported Input Formats are:
+
+ - "dtb": "blob" format. A flattened device-tree block with
+ header in one binary blob.
+
+ - "dts": "source" format. A text file containing a "source"
+ for a device-tree.
+
+ - "fs" format. A representation equivalent to the output of
+ /proc/device-tree where nodes are directories and
+ properties are files.
+
+The currently supported Output Formats are:
+
+ - "dtb": "blob" format
+
+ - "dts": "source" format
+
+ - "asm": assembly language file. A file that can be sourced
+ by gas to generate a device-tree "blob". That file can
+ then simply be added to your Makefile. Additionally, the
+ assembly file exports some symbols that can be used.
+
+
+3) Command Line
+
+The syntax of the dtc command line is:
+
+ dtc [options] [<input_filename>]
+
+Options:
+
+ <input_filename>
+ The name of the input source file. If no <input_filename>
+ or "-" is given, stdin is used.
+
+ -b <number>
+ Set the physical boot cpu.
+
+ -f
+ Force. Try to produce output even if the input tree has errors.
+
+ -h
+ Emit a brief usage and help message.
+
+ -I <input_format>
+ The source input format, as listed above.
+
+ -o <output_filename>
+ The name of the generated output file. Use "-" for stdout.
+
+ -O <output_format>
+ The generated output format, as listed above.
+
+ -q
+ Quiet: -q suppress warnings, -qq errors, -qqq all
+
+ -R <number>
+ Make space for <number> reserve map entries
+ Relevant for dtb and asm output only.
+
+ -S <bytes>
+ Ensure the blob at least <bytes> long, adding additional
+ space if needed.
+
+ -v
+ Print DTC version and exit.
+
+ -V <output_version>
+ Generate output conforming to the given <output_version>.
+ By default the most recent version is generated.
+ Relevant for dtb and asm output only.
+
+
+The <output_version> defines what version of the "blob" format will be
+generated. Supported versions are 1, 2, 3, 16 and 17. The default is
+always the most recent version and is likely the highest number.
+
+Additionally, dtc performs various sanity checks on the tree.
+
+
+4) Device Tree Source file
+
+4.1) Overview
+
+Here is a very rough overview of the layout of a DTS source file:
+
+
+ sourcefile: list_of_memreserve devicetree
+
+ memreserve: label 'memreserve' ADDR ADDR ';'
+ | label 'memreserve' ADDR '-' ADDR ';'
+
+ devicetree: '/' nodedef
+
+ nodedef: '{' list_of_property list_of_subnode '}' ';'
+
+ property: label PROPNAME '=' propdata ';'
+
+ propdata: STRING
+ | '<' list_of_cells '>'
+ | '[' list_of_bytes ']'
+
+ subnode: label nodename nodedef
+
+That structure forms a hierarchical layout of nodes and properties
+rooted at an initial node as:
+
+ / {
+ }
+
+Both classic C style and C++ style comments are supported.
+
+Source files may be directly included using the syntax:
+
+ /include/ "filename"
+
+
+4.2) Properties
+
+Properties are named, possibly labeled, values. Each value
+is one of:
+
+ - A null-teminated C-like string,
+ - A numeric value fitting in 32 bits,
+ - A list of 32-bit values
+ - A byte sequence
+
+Here are some example property definitions:
+
+ - A property containing a 0 terminated string
+
+ property1 = "string_value";
+
+ - A property containing a numerical 32-bit hexadecimal value
+
+ property2 = <1234abcd>;
+
+ - A property containing 3 numerical 32-bit hexadecimal values
+
+ property3 = <12345678 12345678 deadbeef>;
+
+ - A property whose content is an arbitrary array of bytes
+
+ property4 = [0a 0b 0c 0d de ea ad be ef];
+
+
+Node may contain sub-nodes to obtain a hierarchical structure.
+For example:
+
+ - A child node named "childnode" whose unit name is
+ "childnode at address". It it turn has a string property
+ called "childprop".
+
+ childnode at addresss {
+ childprop = "hello\n";
+ };
+
+
+By default, all numeric values are hexadecimal. Alternate bases
+may be specified using a prefix "d#" for decimal, "b#" for binary,
+and "o#" for octal.
+
+Strings support common escape sequences from C: "\n", "\t", "\r",
+"\(octal value)", "\x(hex value)".
+
+
+4.3) Labels and References
+
+Labels may be applied to nodes or properties. Labels appear
+before a node name, and are referenced using an ampersand: &label.
+Absolute node path names are also allowed in node references.
+
+In this exmaple, a node is labled "mpic" and then referenced:
+
+ mpic: interrupt-controller at 40000 {
+ ...
+ };
+
+ ethernet-phy at 3 {
+ interrupt-parent = <&mpic>;
+ ...
+ };
+
+And used in properties, lables may appear before or after any value:
+
+ randomnode {
+ prop: string = data: "mystring\n" data_end: ;
*** DIFF OUTPUT TRUNCATED AT 1000 LINES ***
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