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From: Gorka Guardiola Muzquiz <paurea@gmail.com>
In-Reply-To: <CAGGHmKHw5qPHqYw1QHXbYYdgXpYk0LCQEf9Rfi85+yV+p2isdw@mail.gmail.com>
Date: Thu, 19 Dec 2013 09:38:38 +0100
Cc: "9fans@9fans.net" <9fans@9fans.net>
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References: <CAGGHmKHw5qPHqYw1QHXbYYdgXpYk0LCQEf9Rfi85+yV+p2isdw@mail.gmail.com>
To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net>
Subject: Re: [9fans] gdbfs
Topicbox-Message-UUID: a091243c-ead8-11e9-9d60-3106f5b1d025

=C2=BFHave you taken a look at the jtag tar in my contrib?
It is described here
http://lsub.org/ls/export/jtag.pdf
I don=C2=B4t know enough about the RealView ICE, but if you write
the right module for whatever drives the serial communications
maybe you can drive the jtag directly.
I don=C2=B4t know if that would give you anything you don=C2=B4t have alread=
y
but just in case you didn=C2=B4t know :-)


> On 19 Dec 2013, at 06:12, Steven Stallion <sstallion@gmail.com> wrote:
>=20
> Evening 9fans,
>=20
> While working on the Chromebook (nee exynos) port I ended up in a
> situation where I needed to use a more sophisticated JTAG debugger to
> find an issue. I ended up grabbing a RealView ICE since they are
> relatively cheap on eBay (around 500.00USD) compared to other models
> capable of debugging Cortex-A15 cores. Older firmware revisions of the
> RVI support the remote GDB protocol (in addition to the closed RDDI
> protocol). I've written a simple 9P file server that translates
> memory/register accesses to remote GDB targets. I haven't tried it
> yet, but this should also work with OpenOCD as well.
>=20
> At the moment this is little more than a toy, but it has been stable
> enough for me to debug issues on the board reliably. I've added
> support for ARM and i386 for now - adding additional register maps for
> the other mach types is straightforward. If there is enough demand,
> I'll write up a man page and submit a patch. The setup for this isn't
> particularly obvious since it requires some messing about with RVI
> firmware updates and downloading the right version of RVDS to setup
> the board, so a wiki page is deserved as well.
>=20
> For now, you can find the source in my contrib directory on sources:
> /n/sources/contrib/stallion/src/gdbfs/
>=20
> (Obligatory screenshot attached)
>=20
> Cheers,
>=20
> Steve
> <gdbfs.png>