RDI patches for gdb 4.18

[Grant Edwards]

Attached is a patch file generated agains gdb-4.18.  It implements the
changes listed below for rdi target support.

RDI Background (people who don't know what the rdi target is probably
don't care about the patches, but in case somebody is curious...)

The rdi target is used for remotely debugging ARM targets that
implement the Angel Debugging Protocol (ADP).  ADP is generally
implemented in one of two ways:

 1) By running the Angel Monitor (usually in ROM) on the target and
    talking to it via serial port.  AFAICT, this is quite similar to
    putting GDB stubs on the target.

    I don't have a target that runs the Angel monitor, so I haven't
    tested with this type of target.

 2) By buying an ARM processor with a JTAG debugging interface and
    using a JTAG interface box that implements ADP.  The processor
    that is most commonly used this way is the ARM7TDMI.  

    The two JTAG interfaces with which I have tested are the ARM
    Embedded-ICE and the EPI Jeeni.

Still on the todo list: incoporate changes received from Thomas Zenker
that

 + allow the user to get gdb's attention while it's waiting for an 
   ADP packet.

 + clean up some BSD 4.4 issues

 + clean up the code that opens serial ports (the existing code
   tries to outsmart the user regarding serial port names).

The attached patch should work cleanly if applied in the gdb-4.18 main
directory with the command

    $ patch -E -p4 <gdbrdi.patch



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			       Changes
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 * Added the boolean set/show variable rdiheartbeat.  

   This enables or disables ADP link-check "heartbeat" packets sent by
   the host to the target.  Heartbeat packets can cause both the ARM
   Embedded-ICE and the EPI Jeeni to malfunction: If a heartbeat
   packet is received by the target while it is sending a packet, that
   packet will be aborted, and the ADP protocol engine then gets very
   confused.

   Default state is off -- used to hardwired on.


 * Added the boolean set/show variable rdiromatzero.

   Should be set to true if the target has ROM at address 0.  If true,
   then gdb will not tell the target to trap fetches to interrupt
   vectors (which are located at address 0).  Using the Angel monitor,
   attempting to set breakpoints in ROM is an error.  Using JTAG
   debugging of the ARM7TDMI, attempting to set more than two
   breakpoints in ROM is an error.

   Default state is false (vectors will be trapped) -- used to be
   hardwired false.


 * Added command rdilogenable

   Allows the user to log ADP packets that are exchanged between
   gdb and the target.  Both the raw packets are shown and some
   minimal decoding is attempted.  [new feature]

   Default state is disabled.


 * Added command rdilogfile

   Allows the user to specify the filename to which the ADP packet log
   is to be written.  [new feature]

   Default state is "rdi.log".


 * Changed default names for Linux serial ports from /dev/cuan to
   /dev/ttySn.


 * Added code to split the arguments to the 'target rdi' command at the
   first space.  The first word is passed to Adp_OpenDevice as the
   device name, the tail is passed as the "arguments" parameter.  This
   allows user specified baud rates -- among other things that still
   need to be documented [e.g. (gdb) target rdi /dev/ttyS1 19200].

   NB: With very limited testing, the ARM Embedded-ICE seems to run at
   19.2K (though it is reported to be unreliable above 9600), and the
   EPI Jeeni seems to run at 38.4K.


 * Renamed the file rdi-share/endian.h to rdi-share/anendian.h to prevent
   shadowing of /usr/include/endian.h.  This was causing the wrong
   byte order to be used by htons() in the RDI Ethernet driver.

26 October 1999

Grant Edwards,
Comtrol Corporation

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