[tbot] Testcase / Scripting JTAG Debugger

[Harald Seiler]

Hi Stefano,

On Fri, 2018-12-07 at 10:01 +0100, Stefano Babic wrote:
> On 06/12/18 14:51, Harald Seiler wrote:
> > Hi Stefano,
> > 
> > On Thu, 2018-12-06 at 14:40 +0100, Stefano Babic wrote:
> > > Hi,
> > > 
> > > there are some ready to use testcases for the BDI debugger ?
> > 
> > No, unfortunately not ... Yet!
> > 
> 
> ok, what a pity. I thought tbot uses it to rescue a board after
> installing a broken bootloader.
> 

Hmm, maybe Heiko's version did ...

> > > The debugger does not allow scripting - anyway, this is something tbot
> > > can really help.
> > 
> > Yes, this is exactly what tbot is supposed to automate for you.  I have had
> > debugger support in the back of my head for a long time, but haven't yet
> > had time to implement anything ...
> 
> ok - I have supposed there is something.
> 
> My current problem can be solved in other ways, Lukasz mentions one. I
> have just to push BDI commands without checking the status of the board,
> so I can use even ncat for it.
> 
> > 
> > > I have an old processor where the Flash is not supported by the debugger
> > > fw, but I can rescue the  board after bricking issueing a long list of
> > > CFI commands. What I would like to have is a "BDI" board and a
> > > @tbot.testcase where I can put in a list a set of commands.
> > > 
> > > Is there something to be used ?
> > 
> > So, technically you would need to implement a new machine for this.  Like
> > a BdiMachine, that has the ip address configurable.  I don't have any
> > documentation up for how one would go about doing this I am afraid ...
> 
> It is like a new channel for a board. So board has console and can have
> a BDI attached to it. Both can be used at the same time to control the
> board.
> 
> More advanced testcases can use both of them. Board is started from BDI,
> a breakpoint is set, command are sent via the console, when break is hit
> some BDI commands are sent, then board runs againm and so on.
> 
> > 
> > I might be able to hack something basic up tomorrow that you can expand
> > on as you need.
> 
> Do not be in hurry.
> 
> > 
> > Unfortunately I don't have much experience with bdi so I am not sure
> > what would be needed.  As far as I understood it, we have two interfaces,
> > the telnet console and a gdbserver.
> 
> Yes, they work at the same time - but this depends on JTAG debugger.
> Other debuggers have a different interface.
> 
> For very low-level interaction as what I need now, telnet must be used.

I think for now we should just implement BDI support, because that is what is
used here at DENX.  If the need arises, we can add support for other debuggers
later on.

> >  I guess you need both to work with
> > a BDI effectively?
> > 
> > In that case, we'd have something like:
> > 
> > 	with bdi.BdiMachine(lh) as dbg:
> > 	    dbg.exec0("run", "something", "on", "telnet", "console")
> > 	    dbg.gdb0("run", "something", "on", "gdb", "session")
> > 
> > Does that make sense?
> 
> Yes - this can become more complicate if debugger functionalities
> (breakpoints,..) are used. This would require multithreading in tbot
> (doing something while waiting that a breakpoint is hit). I do not want
> to add so much stuff now, I think the main concern is to provide
> functionalities and features present in the old tbot version.

Actually, it doesn't require multithreading ;) And that is very good,
because multithreading in tbot would be horrible to deal with ... What
we need instead is asynchronous command execution, which is not here
yet either, sadly ...

> Regards,
> Stefano

-- 
Harald

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
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