Basically it's replica of VersatilePB code which is replica of XBox FB
code. All of them are linear framebuffers and should have common bits
moved to reusable framework.
- Disable interrupt when updating compare value in order to
make this operation atomical
- Increase minimum period for event timer. Systimer on BCM2835
is compare timer, so if minimum period is too small it might
be less then fraction of time between "read current value" and
"set compare timer" operations. It means that when timer is armed
actual counter value is more then compare value and it will take
whole cycle (~32sec for 1MHz timer) to fire interrupt.
Submitted by: Daisuke Aoyama <aoyama at peach.ne.jp>
The copies of initarm used on platforms with FDT support were almost
identical. The differences were pulled out into separate functions that
were called by initarm.
This change merges the, now identical, copies of initarm and a few of it's
support functions. This is a step towards a common kernel on ARMv6.
On single core devices set_stackptrs is only ever called with cpu = 0 in
initarm and will be identical to the existing function. On SMP this needs
to be implemented for sys/arm/mp_machdep.c, but the implementations are
identical for each SoC.
