MIPS Creator CI20 patches (again)

Adam Lackorzynski adam at os.inf.tu-dresden.de
Mon Feb 5 00:02:47 CET 2018


On Fri Feb 02, 2018 at 16:45:13 +0100, Paul Boddie wrote:
> On Wednesday 10. January 2018 00.48.03 Adam Lackorzynski wrote:
> > 
> > Adding the .global to the asm block makes thread2 a global symbol which
> > I'd like not to have here (contrary to L4UTIL_THREAD_FUNC). Just doing
> > "static void thread2()" gives warnings because there is no
> > implementation. Looks to me that having a function is much better here.
> > I'll have a look into this.
> > 
> > Thanks for investigating this. And also thanks to James for the nice
> > explanation of the issue.
> 
> I added a patch that works around this problem (l4util-mips-thread.diff) to my 
> collection:
> 
> http://www.boddie.org.uk/paul/L4Re-Fiasco.OC.html
> 
> (Yes, it's the easiest/laziest approach!)
> 
> I have also been trying to extend the CI20 (JZ4780) support to the Ben 
> NanoNote (JZ4740), but success is still out of my reach in this regard. 
> Currently, the NanoNote is refusing to use the serial pins, having done so 
> before from Linux (but not currently, which is worrying), but it has made me 
> wonder about a few aspects of the UART configuration.
> 
> There seems to be a "kernel" UART, but the userspace seems to have the 
> configuration details in l4/pkg/bootstrap/server/src/platform for each board. 
> Does the kernel somehow delegate the configuration to the bootstrap component 
> or is there somewhere in the kernel that needs to be changed for the "kernel" 
> UART? It also makes me wonder about how the jdb communications are configured.

It's the other way around. The booting begins with bootstrap, that's
where the first output happens. Bootstrap then passes the UART config on
to Fiasco, i.e. the UART config that is used in bootstrap is also used
by Fiasco. Do you see the initial output of bootstrap?


Adam




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