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+Templates to help porting freebsd networking drivers
+to rtems (focus on i386 and powerpc) using a 'quick and dirty'
+approach.
+This is not an elegant piece of software -- be warned.
+
+/* Copyright: Till Straumann <strauman@slac.stanford.edu>, 2005;
+ * License:   see LICENSE file.
+ */
+
+Usage:
+
+  A obtain the freebsd driver source. It usually is made
+    up of a
+     if_XXX.c       --  core driver
+     if_XXXreg.h    --  core header
+     if_XXXvar.h    --  some have it, some don't
+     if_XXX_<bus>.c --  glue to integrate the core
+                        driver with different environments
+                        (such as pccard, pci, ...). There
+                        are several of these.
+
+	Note that you might have to get an older version
+	as some structures and interfaces may have undergone
+	significant changes since the bsd/networking version that
+	was ported to rtems.
+
+  B Copy the Makefile and rtemscompat_defs.h templates to the
+    driver source dir and edit them.
+
+  C Edit if_XXXreg.h and comment all unneeded fields from the
+    'softc' structure declaration with
+
+    #ifndef __rtems__
+    #endif
+
+    In particular, the bushandle field (as defined in rtemscompat_defs.h)
+    above, see comments in the template) must be re-declared:
+
+    #ifndef __rtems__
+	bus_space_handle_t  XXX_bhandle;
+	#else
+	unsigned			XXX_bhandle;
+	unsigned char		irq_no;
+	unsigned char		b,d,f;  /* PCI tuple; needed for PCI only */
+	rtems_id			tid;	/* driver task id */
+	#endif
+
+    Later, the compilation attempts will help identifying
+    fields that need to be removed.
+
+	I like the #ifdef __rtems__  construct as it minimizes changes
+    to the source thus making merging updated driver versions easier.
+
+  D Edit if_XXX.c; at the very top, include the lines
+
+    #ifdef __rtems__
+    #include <rtemscompat.h>
+	#endif
+
+	use the #ifndef __rtems__ #endif construct to comment 
+    unneeded / unsupported inclusion of headers and code pieces.
+
+    - inclusion of net/if_media.h must usually be mapped to 
+                   libchip/if_media.h
+   
+    comment all vm, machine, bus, mii etc. related headers.
+
+    - replace inclusion of if_XXXreg.h by
+
+     #include "if_XXXreg.h" 
+     #include <rtemscompat1.h>
+
+    - work through the if_XXX.c and if_XXXreg.h files commenting
+    stuff until if_XXX.c compiles. This might involve hacking
+    the helper headers.
+
+    - pay attention to endian issues; things may need to be fixed!
+
+    - at the top where the freebsd 'methods' and the like are
+    commented, add a definition of the driver methods for RTEMS:
+
+    #ifdef __rtems__
+	net_drv_tbl_t METHODS = {
+		n_probe  : XXX_probe,
+		n_attach : XXX_attach,
+		n_detach : XXX_detach,  /* optional; */
+		n_intr   : XXX_intr,	/* freebsd ISR; executed from daemon under RTEMS */
+	};
+    #endif
+
+	- make sure all the if_xxx methods are set; in particular,
+      set
+		sc->if_output = ether_output;
+
+	- on input:
+		you can use DO_ETHER_INPUT_SKIPPING_ETHER_HEADER() macro
+		-- if you don't MAKE SURE THE RECEIVING INTERFACE IS SET
+		in the mbuf packet header!!!
+
+  E create 'rtems_<chip>_setup()' to probe for devices and
+    set the softc struct's base address, interrupt line and
+    bus/dev/fun triple (PCI only).
+    For PCI devices, a generic setup routine already comes with
+    porting/if_xxx_rtems.c -> nothing needs to be written!