iop: clockevent support

This updates the IOP platform to expose the interrupting
timer 0 as a clockevent object. The timer interrupt handler
is changed to call the clockevent ->event_handler() instead
of timer_tick(), and ->set_next_event() and ->set_mode()
operations are added to allow the mode of the timer to be
updated (required for ONESHOT/NOHZ mode).

Timer 0 must now be properly initialised, which requires
a new write_tcr0() function from the mach-specific code.

The mode of timer 0 must be read at the start of ->set_mode(),
which requires a new read_tmr0() function from the mach-
specific code.

Initial setup of timer 0 is also rewritten to be more robust.

Tested on n2100, compile-tested for all plat-iop machines.

Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 1c4119c60040..e732fcc30526 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -810,6 +810,7 @@ config ARCH_ACORN
 
 config PLAT_IOP
         bool
+        select GENERIC_CLOCKEVENTS
 
 config PLAT_ORION
         bool