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, 12 insertions, 0 deletions

diff --git a/arch/arm/include/asm/hardware/iop3xx.h b/arch/arm/include/asm/hardware/iop3xx.h
index 643b7b95b25..34601b95204 100644
--- a/arch/arm/include/asm/hardware/iop3xx.h
+++ b/arch/arm/include/asm/hardware/iop3xx.h
@@ -236,6 +236,13 @@ void iop_init_cp6_handler(void);
 void iop_init_time(unsigned long tickrate);
 unsigned long iop_gettimeoffset(void);
 
+static inline u32 read_tmr0(void)
+{
+	u32 val;
+	asm volatile("mrc p6, 0, %0, c0, c1, 0" : "=r" (val));
+	return val;
+}
+
 static inline void write_tmr0(u32 val)
 {
 	asm volatile("mcr p6, 0, %0, c0, c1, 0" : : "r" (val));
@@ -253,6 +260,11 @@ static inline u32 read_tcr0(void)
 	return val;
 }
 
+static inline void write_tcr0(u32 val)
+{
+	asm volatile("mcr p6, 0, %0, c2, c1, 0" : : "r" (val));
+}
+
 static inline u32 read_tcr1(void)
 {
 	u32 val;