Re: [Qemu-discuss] system_clock_scale unset in hw/intc/armv7m_nvic.c

[Jakob Bohm]

On 13/01/2017 13:43, Peter Maydell wrote:
> On 13 January 2017 at 12:35, James Hanley <address@hidden> wrote:
> > How should system_clock_scale be set in hw/intc/armv7m_nvic.c - there is no
> > API for the global, and I've defaulted the global to SYSTICK_SCALE which
> > seems to work, but is not obvious.  This was needed as this value was set to
> > zero and the arm firmware was selecting the external clock source causing
> > zero to be returned from systick_scale() and the interrupt to run
> > continuously.
> If I recall correctly, this is an external-to-the-CPU thing
> (wired up by the SoC or the board), which suggests that it
> ought to be a property on the CPU object (or perhaps on a
> currently-nonexistent container object which has the CPU
> and the NVIC and the other M profile devices).
If you are going to add this in the future, I would suggest making it
a settable "board" property, since most "boards" are really just
families of somewhat similar SoC chips, and this frequency might thus
(on real hardware) vary even more easily than e.g. the size of the
available RAM.
> As the code stands today, I think the answer is that the
> board has to set the global -- this is what stellaris.c does.

Enjoy

Jakob
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