Re: [Qemu-devel] [PATCH v9 00/10] 8bit AVR cores

[Peter Maydell]

On 6 July 2016 at 10:49, Michael Rolnik <address@hidden> wrote:
> in the range [0x0000 - 0x0100)
> some registers are owned by the CPU and some by board devices.
> CPU registers will be accessed by helper_fullrd & helper_fullwr whereas
> device registers e.g. USB, will be handled by USB provided it's possible to
> add rd/wr handlers for specific io addresses.

Something like USB which is conceptually separate from the
CPU itself can be implemented as its own device which is mapped
in to the right place in the memory map. You probably want an
"SoC" container device which maps all the various devices
into the right place, and then every board which uses that
particular chip doesn't need to duplicate that code.
There are plenty of examples of this kind of thing: try
the ARM imx boards or the xilinx ones.

thanks
-- PMM