1 files changed, 141 insertions, 35 deletions

diff --git a/arch/arm/plat-iop/time.c b/arch/arm/plat-iop/time.c
index 8da95d57c21f..6c8a02ad98e3 100644
--- a/arch/arm/plat-iop/time.c
+++ b/arch/arm/plat-iop/time.c
@@ -19,6 +19,8 @@
 #include <linux/init.h>
 #include <linux/timex.h>
 #include <linux/io.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
 #include <mach/hardware.h>
 #include <asm/irq.h>
 #include <asm/uaccess.h>
@@ -26,45 +28,136 @@
 #include <asm/mach/time.h>
 #include <mach/time.h>
 
+/*
+ * IOP clocksource (free-running timer 1).
+ */
+static cycle_t iop_clocksource_read(struct clocksource *unused)
+{
+        return 0xffffffffu - read_tcr1();
+}
+
+static struct clocksource iop_clocksource = {
+        .name           = "iop_timer1",
+        .rating         = 300,
+        .read           = iop_clocksource_read,
+        .mask           = CLOCKSOURCE_MASK(32),
+        .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static void __init iop_clocksource_set_hz(struct clocksource *cs, unsigned int hz)
+{
+        u64 temp;
+        u32 shift;
+
+        /* Find shift and mult values for hz. */
+        shift = 32;
+        do {
+                temp = (u64) NSEC_PER_SEC << shift;
+                do_div(temp, hz);
+                if ((temp >> 32) == 0)
+                        break;
+        } while (--shift != 0);
+
+        cs->shift = shift;
+        cs->mult = (u32) temp;
+
+        printk(KERN_INFO "clocksource: %s uses shift %u mult %#x\n",
+               cs->name, cs->shift, cs->mult);
+}
+
+/*
+ * IOP sched_clock() implementation via its clocksource.
+ */
+unsigned long long sched_clock(void)
+{
+        cycle_t cyc = iop_clocksource_read(NULL);
+        struct clocksource *cs = &iop_clocksource;
+
+        return clocksource_cyc2ns(cyc, cs->mult, cs->shift);
+}
+
+/*
+ * IOP clockevents (interrupting timer 0).
+ */
+static int iop_set_next_event(unsigned long delta,
+                              struct clock_event_device *unused)
+{
+        u32 tmr = IOP_TMR_PRIVILEGED | IOP_TMR_RATIO_1_1;
+
+        BUG_ON(delta == 0);
+        write_tmr0(tmr & ~(IOP_TMR_EN | IOP_TMR_RELOAD));
+        write_tcr0(delta);
+        write_tmr0((tmr & ~IOP_TMR_RELOAD) | IOP_TMR_EN);
+
+        return 0;
+}
+
 static unsigned long ticks_per_jiffy;
-static unsigned long ticks_per_usec;
-static unsigned long next_jiffy_time;
 
-unsigned long iop_gettimeoffset(void)
+static void iop_set_mode(enum clock_event_mode mode,
+                         struct clock_event_device *unused)
 {
-        unsigned long offset, temp;
+        u32 tmr = read_tmr0();
+
+        switch (mode) {
+        case CLOCK_EVT_MODE_PERIODIC:
+                write_tmr0(tmr & ~IOP_TMR_EN);
+                write_tcr0(ticks_per_jiffy - 1);
+                tmr |= (IOP_TMR_RELOAD | IOP_TMR_EN);
+                break;
+        case CLOCK_EVT_MODE_ONESHOT:
+                /* ->set_next_event sets period and enables timer */
+                tmr &= ~(IOP_TMR_RELOAD | IOP_TMR_EN);
+                break;
+        case CLOCK_EVT_MODE_RESUME:
+                tmr |= IOP_TMR_EN;
+                break;
+        case CLOCK_EVT_MODE_SHUTDOWN:
+        case CLOCK_EVT_MODE_UNUSED:
+        default:
+                tmr &= ~IOP_TMR_EN;
+                break;
+        }
 
-        /* enable cp6, if necessary, to avoid taking the overhead of an
-         * undefined instruction trap
-         */
-        asm volatile (
-        "mrc    p15, 0, %0, c15, c1, 0\n\t"
-        "tst    %0, #(1 << 6)\n\t"
-        "orreq  %0, %0, #(1 << 6)\n\t"
-        "mcreq  p15, 0, %0, c15, c1, 0\n\t"
-#ifdef CONFIG_CPU_XSCALE
-        "mrceq  p15, 0, %0, c15, c1, 0\n\t"
-        "moveq  %0, %0\n\t"
-        "subeq  pc, pc, #4\n\t"
-#endif
-        : "=r"(temp) : : "cc");
-
-        offset = next_jiffy_time - read_tcr1();
-
-        return offset / ticks_per_usec;
+        write_tmr0(tmr);
+}
+
+static struct clock_event_device iop_clockevent = {
+        .name           = "iop_timer0",
+        .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+        .rating         = 300,
+        .set_next_event = iop_set_next_event,
+        .set_mode       = iop_set_mode,
+};
+
+static void __init iop_clockevent_set_hz(struct clock_event_device *ce, unsigned int hz)
+{
+        u64 temp;
+        u32 shift;
+
+        /* Find shift and mult values for hz. */
+        shift = 32;
+        do {
+                temp = (u64) hz << shift;
+                do_div(temp, NSEC_PER_SEC);
+                if ((temp >> 32) == 0)
+                        break;
+        } while (--shift != 0);
+
+        ce->shift = shift;
+        ce->mult = (u32) temp;
+
+        printk(KERN_INFO "clockevent: %s uses shift %u mult %#lx\n",
+               ce->name, ce->shift, ce->mult);
 }
 
 static irqreturn_t
 iop_timer_interrupt(int irq, void *dev_id)
 {
-        write_tisr(1);
-
-        while ((signed long)(next_jiffy_time - read_tcr1())
-                >= ticks_per_jiffy) {
-                timer_tick();
-                next_jiffy_time -= ticks_per_jiffy;
-        }
+        struct clock_event_device *evt = dev_id;
 
+        write_tisr(1);
+        evt->event_handler(evt);
         return IRQ_HANDLED;
 }
 
@@ -72,6 +165,7 @@ static struct irqaction iop_timer_irq = {
         .name           = "IOP Timer Tick",
         .handler        = iop_timer_interrupt,
         .flags          = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
+        .dev_id         = &iop_clockevent,
 };
 
 static unsigned long iop_tick_rate;
@@ -86,21 +180,33 @@ void __init iop_init_time(unsigned long tick_rate)
         u32 timer_ctl;
 
         ticks_per_jiffy = DIV_ROUND_CLOSEST(tick_rate, HZ);
-        ticks_per_usec = tick_rate / 1000000;
-        next_jiffy_time = 0xffffffff;
         iop_tick_rate = tick_rate;
 
         timer_ctl = IOP_TMR_EN | IOP_TMR_PRIVILEGED |
                         IOP_TMR_RELOAD | IOP_TMR_RATIO_1_1;
 
         /*
-         * We use timer 0 for our timer interrupt, and timer 1 as
-         * monotonic counter for tracking missed jiffies.
+         * Set up interrupting clockevent timer 0.
          */
+        write_tmr0(timer_ctl & ~IOP_TMR_EN);
+        setup_irq(IRQ_IOP_TIMER0, &iop_timer_irq);
+        iop_clockevent_set_hz(&iop_clockevent, tick_rate);
+        iop_clockevent.max_delta_ns =
+                clockevent_delta2ns(0xfffffffe, &iop_clockevent);
+        iop_clockevent.min_delta_ns =
+                clockevent_delta2ns(0xf, &iop_clockevent);
+        iop_clockevent.cpumask = cpumask_of(0);
+        clockevents_register_device(&iop_clockevent);
         write_trr0(ticks_per_jiffy - 1);
+        write_tcr0(ticks_per_jiffy - 1);
         write_tmr0(timer_ctl);
+
+        /*
+         * Set up free-running clocksource timer 1.
+         */
         write_trr1(0xffffffff);
+        write_tcr1(0xffffffff);
         write_tmr1(timer_ctl);
-
-        setup_irq(IRQ_IOP_TIMER0, &iop_timer_irq);
+        iop_clocksource_set_hz(&iop_clocksource, tick_rate);
+        clocksource_register(&iop_clocksource);
 }