[ARM] 4812/1: RealView: clockevents support for the RealView platforms

The patch updates the RealView code to the clockevents infrastructure.
The SMP support is implemented in subsequent patches. Based on the
Versatile implementation by Kevin Hilman.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 67 insertions, 12 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index a2b7e4a52f73..b82828e768ad 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -169,6 +169,7 @@ config ARCH_REALVIEW
         select ARM_AMBA
         select ICST307
         select GENERIC_TIME
+        select GENERIC_CLOCKEVENTS
         help
           This enables support for ARM Ltd RealView boards.
 
diff --git a/arch/arm/mach-realview/core.c b/arch/arm/mach-realview/core.c
index f805840f6f44..6c68deed84dc 100644
--- a/arch/arm/mach-realview/core.c
+++ b/arch/arm/mach-realview/core.c
@@ -26,6 +26,7 @@
 #include <linux/amba/bus.h>
 #include <linux/amba/clcd.h>
 #include <linux/clocksource.h>
+#include <linux/clockchips.h>
 
 #include <asm/system.h>
 #include <asm/hardware.h>
@@ -485,20 +486,77 @@ void realview_leds_event(led_event_t ledevt)
 #define TICKS2USECS(x)  ((x) / TICKS_PER_uSEC)
 #endif
 
+static void timer_set_mode(enum clock_event_mode mode,
+                           struct clock_event_device *clk)
+{
+        unsigned long ctrl;
+
+        switch(mode) {
+        case CLOCK_EVT_MODE_PERIODIC:
+                writel(TIMER_RELOAD, TIMER0_VA_BASE + TIMER_LOAD);
+
+                ctrl = TIMER_CTRL_PERIODIC;
+                ctrl |= TIMER_CTRL_32BIT | TIMER_CTRL_IE | TIMER_CTRL_ENABLE;
+                break;
+        case CLOCK_EVT_MODE_ONESHOT:
+                /* period set, and timer enabled in 'next_event' hook */
+                ctrl = TIMER_CTRL_ONESHOT;
+                ctrl |= TIMER_CTRL_32BIT | TIMER_CTRL_IE;
+                break;
+        case CLOCK_EVT_MODE_UNUSED:
+        case CLOCK_EVT_MODE_SHUTDOWN:
+        default:
+                ctrl = 0;
+        }
+
+        writel(ctrl, TIMER0_VA_BASE + TIMER_CTRL);
+}
+
+static int timer_set_next_event(unsigned long evt,
+                                struct clock_event_device *unused)
+{
+        unsigned long ctrl = readl(TIMER0_VA_BASE + TIMER_CTRL);
+
+        writel(evt, TIMER0_VA_BASE + TIMER_LOAD);
+        writel(ctrl | TIMER_CTRL_ENABLE, TIMER0_VA_BASE + TIMER_CTRL);
+
+        return 0;
+}
+
+static struct clock_event_device timer0_clockevent =     {
+        .name           = "timer0",
+        .shift          = 32,
+        .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+        .set_mode       = timer_set_mode,
+        .set_next_event = timer_set_next_event,
+        .rating         = 300,
+        .irq            = IRQ_TIMERINT0_1,
+        .cpumask        = CPU_MASK_ALL,
+};
+
+static void __init realview_clockevents_init(void)
+{
+        timer0_clockevent.mult =
+                div_sc(1000000, NSEC_PER_SEC, timer0_clockevent.shift);
+        timer0_clockevent.max_delta_ns =
+                clockevent_delta2ns(0xffffffff, &timer0_clockevent);
+        timer0_clockevent.min_delta_ns =
+                clockevent_delta2ns(0xf, &timer0_clockevent);
+
+        clockevents_register_device(&timer0_clockevent);
+}
+
 /*
  * IRQ handler for the timer
  */
 static irqreturn_t realview_timer_interrupt(int irq, void *dev_id)
 {
-        // ...clear the interrupt
-        writel(1, TIMER0_VA_BASE + TIMER_INTCLR);
+        struct clock_event_device *evt = &timer0_clockevent;
 
-        timer_tick();
+        /* clear the interrupt */
+        writel(1, TIMER0_VA_BASE + TIMER_INTCLR);
 
-#if defined(CONFIG_SMP) && !defined(CONFIG_LOCAL_TIMERS)
-        smp_send_timer();
-        update_process_times(user_mode(get_irq_regs()));
-#endif
+        evt->event_handler(evt);
 
         return IRQ_HANDLED;
 }
@@ -564,17 +622,13 @@ static void __init realview_timer_init(void)
         writel(0, TIMER2_VA_BASE + TIMER_CTRL);
         writel(0, TIMER3_VA_BASE + TIMER_CTRL);
 
-        writel(TIMER_RELOAD, TIMER0_VA_BASE + TIMER_LOAD);
-        writel(TIMER_RELOAD, TIMER0_VA_BASE + TIMER_VALUE);
-        writel(TIMER_DIVISOR | TIMER_CTRL_ENABLE | TIMER_CTRL_PERIODIC |
-               TIMER_CTRL_IE, TIMER0_VA_BASE + TIMER_CTRL);
-
         /* 
          * Make irqs happen for the system timer
          */
         setup_irq(IRQ_TIMERINT0_1, &realview_timer_irq);
 
         realview_clocksource_init();
+        realview_clockevents_init();
 }
 
 struct sys_timer realview_timer = {