1 files changed, 141 insertions, 35 deletions

diff --git a/arch/arm/plat-iop/time.c b/arch/arm/plat-iop/time.c
index 8da95d5..6c8a02a 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);
 }