Update from Thomas Doerfler <td@imd.m.isar.de>.

c/src/lib/libbsp/powerpc/helas403/README

@@ -43,6 +43,64 @@ STOP BITS:          1
 Notes
 =====
 
+Board description
+-----------------
+clock rate:	25 MHz
+bus width:	8-bit PROM, 32-bit DRAM
+ROM:		Up to 512KByte (Am29F040), 90 nsec chip select 0
+RAM:		4 to 32 MByte DRAM SIMM (autodetect), 70 nsec,
+		no parity, at CS7 or CS6+CS7 (for two-bank-SIMMs)
+
+
 helas403 only supports single processor operations.
 
+Porting
+-------
+This board support package is written for a typical PPC403GA
+system. The rough features of this board are described above.
+
+This BSP contains files for two startup methods:
+- Direct start from Flash after powerup (with code run out of flash):
+  This is the default configuration, it uses the files
+	flashentry/flashentry.s
+	startup/linkcmds
+
+ Please note, that this configuration is good to startup the system,
+but it will not gain maximum performance due to slow Flash access (8
+bit wide only)
+
+- Start after software download into DRAM:
+  This configuration will use:
+	dlentry/dlentry.s
+	startup/linkcmds.dl
+
+If you want to use the download configuration, it is sufficient to
+rename the file "startup/linkcmds.dl" to "startup/linkcmds", it will
+automatically reference the dlentry.s as entry code. (Renaming is not
+quite elegant, a more sophisticated solution will follow in future,
+any hints welcome ;-)
+
+For adapting this BSP to other boards, the following files should be
+modified:
+
+- c/src/lib/libbsp/powerpc/helas403/flashentry/flashentry.s
+	for the memory controller configuration and other basic stuff
+
+- c/src/lib/libbsp/powerpc/helas403/startup/linkcmds[.dl]
+	for the memory layout required
+
+- c/src/lib/libbsp/powerpc/helas403/startup/bspstart.c
+	for adaption of BSP_Configuration. here you can select
+	the clock source for the timers and the serial interface
+	(system clock or external clock pin), the clock rates, initial
+	baud rate and other stuff
+
+- c/src/lib/libbsp/powerpc/helas403/include/bsp.h
+	some BSP-related constants
+
+The actual drivers are placed in 
+- c/src/lib/libcpu/powerpc/ppc403/*
+	well, they should be generic, so there _should_ be no reason
+	to mess around there (but who knows...)
+