RPI 2 should not be that bad: I changed the peripheral register base in raspberrypi.h, changed the compilation arch flags, commented out the mmu init call, and some samples seem to work.
I ran ticker and paranoia Alan On Thu, Mar 5, 2015 at 7:42 PM, <alan.cudm...@gmail.com> wrote: > I think this will be possible. I just tried a few bare metal assembly > demos on the Pi A+ and Pi2 and it looks like even without the published CPU > datasheet, they have things figured out. > > For example: An assembly SMP NEON fractal demo: > > https://github.com/PeterLemon/RaspberryPi/tree/master/SMP/NEON/Fractal/Julia > > Another interesting thing: The same SD card firmware works for both the Pi > and Pi2. The Pi2 boots kernel7.img, and the pi looks for kernel.img. > > > Alan > > > *From:* Joel Sherrill <joel.sherr...@oarcorp.com> > *Sent:* Thursday, March 5, 2015 1:42 PM > *To:* rtems-de...@rtems.org <devel@rtems.org>, Alan Cudmore > <alan.cudm...@gmail.com> > > Hi > > I am going to go back on what I said earlier. The online discussion > seems to indicate that the BCM2836 has the same peripherals > as the BCM2835 on the previous Pi Models. But they are at > physical address 0x3F000000 rather than the 0x20000000. > The CPU core is a different ARM level. > > Since people are having luck on the net and the source > for Linux can always be consulted if there are specific > register issues we can't figure out, I *THINK* that a > BSP variant for this makes sense as a GSoC project. > > That would be an additional project to bring up the single > core as step 1, support SMP and test drivers done on other > single core Pi project. Maybe by the end of the summer , > both can be supported with the same driver set. > > -- > Joel Sherrill, Ph.D. Director of Research & Development > joel.sherr...@oarcorp.com On-Line Applications Research > Ask me about RTEMS: a free RTOS Huntsville AL 35805 > Support Available (256) 722-9985 > >
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