Skip to content

S
SDB - Self-describing Bus
Commit 222aa8d6 authored by Alessandro Rubini's avatar Alessandro Rubini
Browse files
Options

docs: another small pass, at least it compiles now 

Signed-off-by: Alessandro Rubini's avatarAlessandro Rubini <rubini@gnudd.com>
parent 78242c7a
Hide whitespace changes
Inline Side-by-side
Showing with 36 additions and 24 deletions
docs/specification/proposal.tex
View file @ 222aa8d6
......@@ -208,7 +208,7 @@ the encompassing address space and includes a \textit{product}
structure.
\item[Interconnect] \hfill \\
The \textitinterconnect} is a \textitcomponent} representing an address demultiplexer.
The \textit{interconnect} is a \textit{component} representing an address demultiplexer.
The associated data structure heads an array of \textit{product} descriptions;
its specific fields are magic number, bus type, version and the number of
structures in the array.
......@@ -448,37 +448,49 @@ tools and system calls.
\section{SDB Structures}
This section defines the structures that are to be embedded in the
address space of the target bus. The words \textbf{shall},
\textbf{must}, \textbf{should}, \textbf{may}, \textbf{can} have the
usual normative meaning when used in bold face.
Note: the document has not been updated after this point.
\vfill
\subsection{Definitions}
This section describes the important structures that are a part of the SDB specification.
\subsection{SDB Table}
\begin{description}
\item[SDB Structure] \hfill \\
A 64-byte memory area, located within the bus being described
at a known address. The structure \textbf{must} bit 64-byte aligned
and it \textbf{must} be readable with
32-bit I/O transactions. The bus \textbf{may} allow 64-bit, 16-bit
and 8-bit access to the structure. Code reading the structure
\textbf{should} use 32-bit transfers, and \textbf{can} use different
sizes only when aware of the specifics of the bus.
\item[SDB Record] \hfill \\
A synonym for \textit{SDB structure}.
\item[SDB Array or SDB Table] \hfill \\
An in-memory array of SDB records. The records \textbf{must}
be contiguous with no intervening holes, and the table \textbf{must}
be aligned at a 64-byte boundary.
he first SDB structure in the array \textbf{must} be an \textit{interconnect}
record.
\item[SDB Product] \hfill \\
A data structure hosted within some SDB records. All currently defined
record types are \textit{products}.
\item[SDB Component] \hfill \\
A data structure hosted within some SDB records. A \textit{component}
includes a \textit{product} structure and defines an address range.
The most important structure that needs to be present in a design to support SDB
based autodiscovery is the SDB table.
\end{description}
The SDB table is a contiguous array of records that provides the needed metadata
about devices. There is no restriction placed on where this table is located in
memory and the higher levels only need to know the location of the top-level table
to recursively discover the descriptions of all the blocks.
The following sections define the details of each structure.
An SDB table is composed of multiple SDB records. There are four different types of
SDB records that can be used to describe different parts of the design.
\begin{enumerate}
\item Interconnect Record
\item Device Record
\item Bridge Record
\item Integrator Record
\end{enumerate}
\subsection{SDB Product Info}
\subsection{SDB Product Structure}
The SDB product info structure is a 40 byte structure that provides information about
the specific product being described. The information provided here is used for device
identification.
\begin{center}
\begin{savenotes}
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment