[PATCH V4 2/2] riscv: board: Support OpenPiton SoC

[Bin Meng]

Hi Tianrui,

On Thu, May 13, 2021 at 1:07 PM Tianrui Wei <tianrui-wei at outlook.com> wrote:
>
> Hi Sean,
>
> On 5/13/2021 1:14 AM, Sean Anderson wrote:
> >
> > [snip]
> >
> >> On 5/8/2021 11:14 PM, Sean Anderson wrote:
> >>> On 5/8/21 12:57 AM, Tianrui Wei wrote:
> >>>> On 5/7/2021 9:03 PM, Sean Anderson wrote:
> >>>>> On 5/6/21 11:48 PM, Tianrui Wei wrote:
> >>>>>> On 5/7/2021 11:41 AM, Sean Anderson wrote:
> >>>>>>> On 5/6/21 11:28 PM, Tianrui Wei wrote:
> >>>>>>>> On 5/7/2021 11:15 AM, Sean Anderson wrote:
> >>>>>>>>> On 5/6/21 11:06 PM, Tianrui Wei wrote:
> >>>>>>>>>> On 5/7/2021 10:32 AM, Sean Anderson wrote:
> >>>>>>>>>>> Please use a log without debug uart.
> >>>>>>>>>>>
> >>>>>>>>>> So this is the part where it was a little confusing. Disabling
> >>>>>>>>>> debug uart acutally doesn't work for some reason, so we had to
> >>>>>>>>>> keep it open. Will submit another patch if we got it working
> >>>>>>>>>> with debug uart turned off.
> >>>>>>>>>
> >>>>>>>>> This is a bit of a strange request, but can you try adding
> >>>>>>>>> some nops()
> >>>>>>>>> (around 10-30) to some function (e.g. board_init). I've been
> >>>>>>>>> having
> >>>>>>>>> alignment problems in k210, so it could be something similar.
> >>>>>>>>>
> >> I was wondering if you have any idea what may cause the alignment
> >> problems, we're also hitting it constantly and adding nops seems to
> >> have no impact so far.
> >
> > I have no idea :)
> >
> > If adding nop()s doesn't solve it, it may not be an alignment problem.
> > You can also try switching from -Os to -O2, which should move things
> > around a bit.
> >
> > My attempts to dig into this have been stymied by the poor debugging
> > tools for the k210. The upstream openocd port only supports debugging
> > hart 0. While Canaan's fork supports debugging both harts, you must pick
> > the one to debug when launching the debugger. And both debuggers are
> > very buggy themselves.
> >
> > The other problem on the k210 at least is that the typical failure mode
> > (trying to read from unaddressable/unmapped addresses) hangs the bus.
> > This also has the tendancy of hanging the jtag debug port.
>
>
> I did try to switch from -Os to -O2, and it didn't help either. I've
> also encountered
>
> the same debugger situation unfortunately, so I have not much luck
> finding the
>
> faulty instruction either.  Maybe we should bring this issue up with the
> others along
>
> the compilation error?

Sorry I lost the track. What problems are you seeing?

Regards,
Bin