>software needs to do more complicated stuff like
>display results and understand CPU debug modes etc.
The JTAG Debug Support on the PXA is considerable and will need quite some
work to be useable. Is this what openOCD provides?
>Currently for 1) we use jflash on balloon2 and bflash on balloon3, both
with
>the xilinx-a-like dongle. Does bflash support balloon2 as well?
Yes bflash supports balloon2, and is (in theory) easily extensible to other
systems and devices both in terms of the FLASH devices and other (multiple)
devices in the JTAG chain in a system, since the internal data structures
are based on the data in a BSDL file. (In fact a BSDL parser could be used
to create them if anyone can be bothered to write one).
>It would make sense to use existing open hardware/free software solutions
>where these are sufficient for our needs, or likely to become so with a bit
>of development, rather than inventing all this stuff again ourselves, so I
>took a look at what is available.
It would be useful to know what else is out there.
>For hardware it supports wigglers (which I think correspond to our dongles
>- if not adding support would be trivial - someone needs to test this), and
>FT2232-based usb devices, which seems to be the way everyone is implmenting
>fast devices. You can layout your own from this:
>http://www.ftdichip.com/Projects/MPSSE/FT2232C-Proj03_v11.pdf
This will be difficult to test until openOCD supports the PXA and the
Balloon board...
It may be worth using this as the basis for the new balloon dongle....
Or using one of the ones already out there.
Whatever we go for we will need to support in our tools and we will need to
provide a connector link from the massive 0,1" pitch bit of 1970's
technology to the 0,5mm pitch stuff that comes off Balloons. :-)
(As was pointed out at the recent developers meeting this is likely to be a
useful sacrificial point in the connector chain.)
>The main thing missing at the moment, that we need, is multi-chain support.
>OpenOCD supports multi-cores but only one JTAG chain right now.
It is also likely that the hardware dongles mentioned above also only
support a single JTAG chain, this is one reason why we may want to build our
own dongle (which can be made generic).
>We are not the only people that would like this feature. Domonic thinks
>"that could be added quite easily", but not for at least a couple of weeks
>as he currently has finals. Sending him a balloon to experiment on would
>probably help.
Balloon2 has multiple chains but the jtag dongle doesn't allow simultaneous
access, so there isn't anything that can be progressed on that front until
we have a JTAG dongle with multi-chain support.
>It seems to me that we would be better off adding multi-chain, our dongle,
>and strongarm support to this framework, and using the available, supported
>faster JTAG hardware than by developing something from scratch ourselves.
Obviously we need to pick up what we can however the lack of support for
exactly our configuration means that this collaboration may take a while to
materialise. It is possible that bflash can be grafted onto/provide support
for the higher levels in openOCD but this needs a much more detailed
investigation, it may simply be easier to add the support we need for PXA
etc to openOCD... (discuss)...
>Wookey
David
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