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SDB - Self-describing Bus
Commit 3958079a authored by Wesley W. Terpstra's avatar Wesley W. Terpstra Committed by Alessandro Rubini
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specification: minor rewording and typos 

This is mainly due to feedback by Matthieu Cattin and Wesley Terpstra
Signed-off-by: Alessandro Rubini's avatarAlessandro Rubini <rubini@gnudd.com>
parent 9a5ca75e
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docs/specification/sdb.tex
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......@@ -48,7 +48,7 @@ Manohar Vanga (CERN, BE/CO/HT)}
\section*{Bugs}
Even though we already reached 1.0 and are proceeding, there are still some
Even though the project already passed the 1.0 milestone, there are still some
things that ought to be changed or added:
\begin{itemize}
......@@ -56,8 +56,7 @@ things that ought to be changed or added:
\item The description of the record type should get a more prominent place than the
current description in the \textit{product} structure;
\item We need a policy for designers adding class etc, and it must be described;
\item Wishbone-specific flags deserve a subsection;
\item Filesystem-specific flags must be defined and documented.
\item A reference implementation exists, but it is not described here.
\end{itemize}
\section*{Versioning}
......@@ -189,11 +188,11 @@ SDB was born as a description of address spaces. Access to address
spaces is usually done through \textit{bus} signals, according to the
bus specification: signal lines, protocols, timings. Interrupts
strictly-speaking are not part of the bus: they are a sort of a
``parallel'' bus, whereas one signal line connects one core to the
``interrupt controller'' core. The same applies to the so-called
``DMA channels'' used in some designs: there a FIFO and the
request/ack signals connect a slave-only core to the DMA controller
that can act as a master on behalf of the slave.
``secondary'' bus, where only one signal line connects one core to the
``interrupt controller'' core. The same applies to the out-of-band
DMA channels used in some designs, where two devices are connected via
a path not part of the normal bus interconnect fabric.
In that case the DMA controller can act as a master on behalf of the slave.
We currently don't offer such descriptions because we really think
designs should be converted to the concept of MSI interrupts, and
......@@ -326,7 +325,7 @@ an output as opposed to adding a bus master interface. However,
this ``simplicity'' argument ignores the costs that happen once you have
enough of these devices, once the
interrupt bus becomes non-trivial. To keep the code simple, one could
easily imagine a small VHDL component that takes an address register and
easily imagine a small HDL component that takes an address register and
a generates a write upon request.
To use MSI and achieve compatibility with a legacy master like
......@@ -832,8 +831,8 @@ unknown record type in the range 0x00-0x7f is found; unknown records in the rang
sdb\_type\_repo\_url & 0x81 & Informative: repository location \\ \hline
sdb\_type\_synthesis & 0x80 & Informative: synthesis details \\ \hline
& 0x83-0xef & Reserved for future informative records \\ \hline
& 0xf0-0xfef & Local/temporary use \\ \hline
sdb\_type\_empty & 0xFF & Empty record \\ \hline
& 0xf0-0xfe & Local/temporary use \\ \hline
sdb\_type\_empty & 0xff & Empty record \\ \hline
\end{tabular}
\end{table}
\end{savenotes}
......@@ -1145,7 +1144,7 @@ Actually, this data structure is already implemented in one ADC design.
\begin{description}
\item[repo\_url] \hfill \\
This a string, encoded in UTF-8, with trailing spaces and no terminating 0.
This is a string, encoded in UTF-8, with trailing spaces and no terminating 0.
It is expected to name the top-level repository
used to build this design, as a \texttt{git://} or \texttt{http://} form or
anything appropriate for the revision control system being used.
......@@ -1197,7 +1196,7 @@ with great care or the initial effort to provided detailed tracking is voided.
\begin{description}
\item[syn\_name] \hfill \\
This a string, encoded in UTF-8, with trailing spaces and no terminating 0;
This is a string, encoded in UTF-8, with trailing spaces and no terminating 0;
it should represent a human-readable name for this synthesis. Like all other
fields in this structures, it is meant to be useful for the designers, to help
tracking what is currently installed in the various systems. Thus, this may
......@@ -1219,7 +1218,7 @@ change is a sensible workaround. The filed \textbf{should} be 0 if not used.
\item[tool\_name] \hfill \\
This a string, encoded in UTF-8, with trailing spaces and no terminating 0;
This is a string, encoded in UTF-8, with trailing spaces and no terminating 0;
it represents a human-readable name for the synthesis tool used to build this
very binary gateware file.
......@@ -1233,7 +1232,7 @@ The date of synthesis. This \textbf{must} be either 0 (unspecified) or a 32-bit
format number in the format 0xYYYYMMDD. For example, 0x20130327.
\item[user\_name] \hfill \\
This a string, encoded in UTF-8, with trailing spaces and no terminating 0;
This is a string, encoded in UTF-8, with trailing spaces and no terminating 0;
it states who is the user who built the binary gateware. This name is expected
to be unique among the development group, so a Unix username or a nickname are good
choices that fit the allowed space of 15 bytes.
......
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