On Sat, May 03, 2014 at 10:50:16AM -0700, Duane Ellis wrote: > > So if OpenOCD gains support for this kind of AP, it'll need to > > basically handle two completely different JTAG chains at the same > > time. > > Exactly correct. > > > I think that implementing that would be unreasonably hard (due to > > lots of assumptions, global variables etc) and on the other hand > > running a separate openocd instance with special interface driver > > would be quite easy, hence my proposal. > > Are you familiar with Rube Goldberg Designs … A very american > cartoon. (British may recognize: W. Heath Robinson)
Hehe, fascinating. I hope my proposal to have an openocd instance per jtag chain is actually not that bizarre, and it's way easier to implement compared to possible alternatives. Let's see what the others have to say though, it's quite likely I'm just stuck now on my "simple" solution and can't see anything past it. > Why not just keep this in the TAP structure… Because I may need to > access memory without referring to a target… Example: I want the DAP > to access system memory by way of the system memory port. > > Today - for JTAG, the DAP = TAP I guess the main counter-argument is that DAP is something ARM-specific while TAP is JTAG-generic, so I guess what Andreas was unhappy with was this layering violation. E.g. what if some other non-ARM architecture would start demanding two "DAPs" per TAP, should yet another field be added to the tap struct then? > For SWD - that uses the underling TAP structure … > > If I had two SWDs - there would be TWO tap structures… Right, it would fit currently but I believe people would prefer to get rid of this hack eventually. I guess we have discussed everything reasonably thoroughly by now; I'd very much like to hear Andreas's opinion on all this. -- Be free, use free (http://www.gnu.org/philosophy/free-sw.html) software! mailto:[email protected] ------------------------------------------------------------------------------ "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE Instantly run your Selenium tests across 300+ browser/OS combos. Get unparalleled scalability from the best Selenium testing platform available. Simple to use. Nothing to install. Get started now for free." http://p.sf.net/sfu/SauceLabs _______________________________________________ OpenOCD-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/openocd-devel
