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authorRonald G. Minnich <rminnich@gmail.com>2009-04-20 22:10:34 +0000
committerRonald G. Minnich <rminnich@gmail.com>2009-04-20 22:10:34 +0000
commitb88a1fcd804ecd9f5aeaaf542e741478a11d36ab (patch)
treebfaf4e8a25c5cadaed1c63c4d3f2b9a195923707 /documentation
parentfeaaedc1cf99c12b8d1ab4bb233a311044d7f8b0 (diff)
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A little more info. Failover docs are next, then proposed new mechanism
Signed-off-by: Ronald G. Minnich <rminnich@gmail.com> Acked-by: Ronald G. Minnich <rminnich@gmail.com> git-svn-id: svn://svn.coreboot.org/coreboot/trunk@4145 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1
Diffstat (limited to 'documentation')
-rw-r--r--documentation/LinuxBIOS-AMD64.tex49
1 files changed, 44 insertions, 5 deletions
diff --git a/documentation/LinuxBIOS-AMD64.tex b/documentation/LinuxBIOS-AMD64.tex
index 71b1e3cab..9937f16fe 100644
--- a/documentation/LinuxBIOS-AMD64.tex
+++ b/documentation/LinuxBIOS-AMD64.tex
@@ -1643,16 +1643,55 @@ No significant change from romcc code.
\subsubsection{boot sequence}
No significant change from romcc code, except that the CAR code has to set up a stack.
-\subsection{car + CONFIG\_USE\_INIT images}
+\subsection{car + CONFIG\_USE\_INIT images (new emulation/qemu}
+This type of image makes more use of the C compiler. In this type of image, in fact,
+seperate compilation is possible but is not always used. Oddly enough, this option is only used in PPC boards. That said, we need to move to this way of building. Including C code is poor style.
\subsubsection{how it is built}
+There is a make variable, INIT-OBJECTS, that for all our other targets is empty. In this type of build, INIT-OBJECTS is a list of C files that are created from the config tool initobject command. Again, with INIT-OBJECTS we can finally stop including .c files and go with seperate compilation.
\subsubsection{layout}
+No significant change from romcc code.
\subsubsection{boot sequence}
-We boot and start at fffffff0. We then jump to the entry point at protected\_start (a clear misnomer, since we're not in protected mode at that
-point). Protected\_start does an lgdt and jumps to \_\_protected\_start, at which point we are in protected mode.
-
+No significant change from romcc code, except that the CAR code has to set up a stack.
\subsection{car + CONFIG\_USE\_PRINTK\_IN\_CAR images}
-When CONFIG\_USE\_PRINTK\_IN\_CAR is set, the CAR code can use printk instead of the primitive print functions.
+When CONFIG\_USE\_PRINTK\_IN\_CAR is set, the CAR code can use printk instead of the primitive print functions. This config variable is used in one of two ways. If CONFIG\_USE\_INIT is 0, then different .c files just include other .c files, as in console.c:
+\begin{verbatim}
+#if CONFIG_USE_PRINTK_IN_CAR == 0
+static void __console_tx_byte(unsigned char byte)
+{
+ uart_tx_byte(byte);
+}
+
+#include "console_print.c"
+
+#else
+/* CONFIG_USE_PRINTK_IN_CAR == 1 */
+
+#include "console_printk.c"
+
+#if CONFIG_USE_INIT == 0
+// do_printk
+#include "../../../console/vtxprintf.c"
+#include "printk_init.c"
+#endif
+#endif /* CONFIG_USE_PRINTK_IN_CAR */
+
+\end{verbatim}\footnote{yuck!}
+
+If CONFIG\_USE\_INIT is 1, then the Config.lb is configured differently:
+\begin{verbatim}
+if CONFIG_USE_INIT
+ if CONFIG_USE_PRINTK_IN_CAR
+ initobject printk_init.o
+ end
+end
+
+\end{verbatim}\footnote{see previous footnote}
+
+\subsubsection{layout}
+No significant change from romcc code.
+\subsubsection{boot sequence}
+No significant change from romcc code, except that the CAR code has to set up a stack.
\subsection{failover}
%