1 files changed, 110 insertions, 188 deletions

diff --git a/arch/avr32/kernel/time.c b/arch/avr32/kernel/time.c
index b0e6b5855a3..d0f771be9e9 100644
--- a/arch/avr32/kernel/time.c
+++ b/arch/avr32/kernel/time.c
@@ -1,238 +1,160 @@
 /*
- * Copyright (C) 2004-2006 Atmel Corporation
- *
- * Based on MIPS implementation arch/mips/kernel/time.c
- *   Copyright 2001 MontaVista Software Inc.
+ * Copyright (C) 2004-2007 Atmel Corporation
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */
-
 #include <linux/clk.h>
-#include <linux/clocksource.h>
-#include <linux/time.h>
-#include <linux/module.h>
+#include <linux/clockchips.h>
+#include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
-#include <linux/kernel_stat.h>
-#include <linux/errno.h>
-#include <linux/init.h>
-#include <linux/profile.h>
-#include <linux/sysdev.h>
+#include <linux/kernel.h>
+#include <linux/time.h>
+#include <linux/cpu.h>
 
-#include <asm/div64.h>
 #include <asm/sysreg.h>
-#include <asm/io.h>
-#include <asm/sections.h>
-
-static cycle_t read_cycle_count(void)
-{
-	return (cycle_t)sysreg_read(COUNT);
-}
-
-static struct clocksource clocksource_avr32 = {
-	.name		= "avr32",
-	.rating		= 350,
-	.read		= read_cycle_count,
-	.mask		= CLOCKSOURCE_MASK(32),
-	.shift		= 16,
-	.is_continuous	= 1,
-};
-
-/*
- * By default we provide the null RTC ops
- */
-static unsigned long null_rtc_get_time(void)
-{
-	return mktime(2004, 1, 1, 0, 0, 0);
-}
 
-static int null_rtc_set_time(unsigned long sec)
-{
-	return 0;
-}
-
-static unsigned long (*rtc_get_time)(void) = null_rtc_get_time;
-static int (*rtc_set_time)(unsigned long) = null_rtc_set_time;
-
-/* how many counter cycles in a jiffy? */
-static unsigned long cycles_per_jiffy;
-
-/* cycle counter value at the previous timer interrupt */
-static unsigned int timerhi, timerlo;
-
-/* the count value for the next timer interrupt */
-static unsigned int expirelo;
-
-static void avr32_timer_ack(void)
-{
-	unsigned int count;
-
-	/* Ack this timer interrupt and set the next one */
-	expirelo += cycles_per_jiffy;
-	if (expirelo == 0) {
-		printk(KERN_DEBUG "expirelo == 0\n");
-		sysreg_write(COMPARE, expirelo + 1);
-	} else {
-		sysreg_write(COMPARE, expirelo);
-	}
+#include <mach/pm.h>
 
-	/* Check to see if we have missed any timer interrupts */
-	count = sysreg_read(COUNT);
-	if ((count - expirelo) < 0x7fffffff) {
-		expirelo = count + cycles_per_jiffy;
-		sysreg_write(COMPARE, expirelo);
-	}
-}
-
-static unsigned int avr32_hpt_read(void)
-{
-	return sysreg_read(COUNT);
-}
-
-/*
- * Taken from MIPS c0_hpt_timer_init().
- *
- * Why is it so complicated, and what is "count"?  My assumption is
- * that `count' specifies the "reference cycle", i.e. the cycle since
- * reset that should mean "zero". The reason COUNT is written twice is
- * probably to make sure we don't get any timer interrupts while we
- * are messing with the counter.
- */
-static void avr32_hpt_init(unsigned int count)
-{
-	count = sysreg_read(COUNT) - count;
-	expirelo = (count / cycles_per_jiffy + 1) * cycles_per_jiffy;
-	sysreg_write(COUNT, expirelo - cycles_per_jiffy);
-	sysreg_write(COMPARE, expirelo);
-	sysreg_write(COUNT, count);
-}
 
-/*
- * Scheduler clock - returns current time in nanosec units.
- */
-unsigned long long sched_clock(void)
+static cycle_t read_cycle_count(struct clocksource *cs)
 {
-	/* There must be better ways...? */
-	return (unsigned long long)jiffies * (1000000000 / HZ);
+	return (cycle_t)sysreg_read(COUNT);
 }
 
 /*
- * local_timer_interrupt() does profiling and process accounting on a
- * per-CPU basis.
- *
- * In UP mode, it is invoked from the (global) timer_interrupt.
+ * The architectural cycle count registers are a fine clocksource unless
+ * the system idle loop use sleep states like "idle":  the CPU cycles
+ * measured by COUNT (and COMPARE) don't happen during sleep states.
+ * Their duration also changes if cpufreq changes the CPU clock rate.
+ * So we rate the clocksource using COUNT as very low quality.
  */
-static void local_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
-{
-	if (current->pid)
-		profile_tick(CPU_PROFILING, regs);
-	update_process_times(user_mode(regs));
-}
+static struct clocksource counter = {
+	.name		= "avr32_counter",
+	.rating		= 50,
+	.read		= read_cycle_count,
+	.mask		= CLOCKSOURCE_MASK(32),
+	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
+};
 
-static irqreturn_t
-timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+static irqreturn_t timer_interrupt(int irq, void *dev_id)
 {
-	unsigned int count;
+	struct clock_event_device *evdev = dev_id;
 
-	/* ack timer interrupt and try to set next interrupt */
-	count = avr32_hpt_read();
-	avr32_timer_ack();
-
-	/* Update timerhi/timerlo for intra-jiffy calibration */
-	timerhi += count < timerlo;	/* Wrap around */
-	timerlo = count;
+	if (unlikely(!(intc_get_pending(0) & 1)))
+		return IRQ_NONE;
 
 	/*
-	 * Call the generic timer interrupt handler
+	 * Disable the interrupt until the clockevent subsystem
+	 * reprograms it.
 	 */
-	write_seqlock(&xtime_lock);
-	do_timer(regs);
-	write_sequnlock(&xtime_lock);
-
-	/*
-	 * In UP mode, we call local_timer_interrupt() to do profiling
-	 * and process accounting.
-	 *
-	 * SMP is not supported yet.
-	 */
-	local_timer_interrupt(irq, dev_id, regs);
+	sysreg_write(COMPARE, 0);
 
+	evdev->event_handler(evdev);
 	return IRQ_HANDLED;
 }
 
 static struct irqaction timer_irqaction = {
 	.handler	= timer_interrupt,
-	.flags		= IRQF_DISABLED,
-	.name		= "timer",
+	/* Oprofile uses the same irq as the timer, so allow it to be shared */
+	.flags		= IRQF_TIMER | IRQF_SHARED,
+	.name		= "avr32_comparator",
 };
 
-void __init time_init(void)
+static int comparator_next_event(unsigned long delta,
+		struct clock_event_device *evdev)
 {
-	unsigned long mult, shift, count_hz;
-	int ret;
+	unsigned long	flags;
 
-	xtime.tv_sec = rtc_get_time();
-	xtime.tv_nsec = 0;
+	raw_local_irq_save(flags);
 
-	set_normalized_timespec(&wall_to_monotonic,
-				-xtime.tv_sec, -xtime.tv_nsec);
+	/* The time to read COUNT then update COMPARE must be less
+	 * than the min_delta_ns value for this clockevent source.
+	 */
+	sysreg_write(COMPARE, (sysreg_read(COUNT) + delta) ? : 1);
 
-	printk("Before time_init: count=%08lx, compare=%08lx\n",
-	       (unsigned long)sysreg_read(COUNT),
-	       (unsigned long)sysreg_read(COMPARE));
+	raw_local_irq_restore(flags);
 
-	count_hz = clk_get_rate(boot_cpu_data.clk);
-	shift = clocksource_avr32.shift;
-	mult = clocksource_hz2mult(count_hz, shift);
-	clocksource_avr32.mult = mult;
+	return 0;
+}
 
-	printk("Cycle counter: mult=%lu, shift=%lu\n", mult, shift);
+static void comparator_mode(enum clock_event_mode mode,
+		struct clock_event_device *evdev)
+{
+	switch (mode) {
+	case CLOCK_EVT_MODE_ONESHOT:
+		pr_debug("%s: start\n", evdev->name);
+		/* FALLTHROUGH */
+	case CLOCK_EVT_MODE_RESUME:
+		/*
+		 * If we're using the COUNT and COMPARE registers we
+		 * need to force idle poll.
+		 */
+		cpu_idle_poll_ctrl(true);
+		break;
+	case CLOCK_EVT_MODE_UNUSED:
+	case CLOCK_EVT_MODE_SHUTDOWN:
+		sysreg_write(COMPARE, 0);
+		pr_debug("%s: stop\n", evdev->name);
+		if (evdev->mode == CLOCK_EVT_MODE_ONESHOT ||
+		    evdev->mode == CLOCK_EVT_MODE_RESUME) {
+			/*
+			 * Only disable idle poll if we have forced that
+			 * in a previous call.
+			 */
+			cpu_idle_poll_ctrl(false);
+		}
+		break;
+	default:
+		BUG();
+	}
+}
 
-	{
-		u64 tmp;
+static struct clock_event_device comparator = {
+	.name		= "avr32_comparator",
+	.features	= CLOCK_EVT_FEAT_ONESHOT,
+	.shift		= 16,
+	.rating		= 50,
+	.set_next_event	= comparator_next_event,
+	.set_mode	= comparator_mode,
+};
 
-		tmp = TICK_NSEC;
-		tmp <<= shift;
-		tmp += mult / 2;
-		do_div(tmp, mult);
+void read_persistent_clock(struct timespec *ts)
+{
+	ts->tv_sec = mktime(2007, 1, 1, 0, 0, 0);
+	ts->tv_nsec = 0;
+}
 
-		cycles_per_jiffy = tmp;
-	}
+void __init time_init(void)
+{
+	unsigned long counter_hz;
+	int ret;
 
-	/* This sets up the high precision timer for the first interrupt. */
-	avr32_hpt_init(avr32_hpt_read());
+	/* figure rate for counter */
+	counter_hz = clk_get_rate(boot_cpu_data.clk);
+	ret = clocksource_register_hz(&counter, counter_hz);
+	if (ret)
+		pr_debug("timer: could not register clocksource: %d\n", ret);
 
-	printk("After time_init: count=%08lx, compare=%08lx\n",
-	       (unsigned long)sysreg_read(COUNT),
-	       (unsigned long)sysreg_read(COMPARE));
+	/* setup COMPARE clockevent */
+	comparator.mult = div_sc(counter_hz, NSEC_PER_SEC, comparator.shift);
+	comparator.max_delta_ns = clockevent_delta2ns((u32)~0, &comparator);
+	comparator.min_delta_ns = clockevent_delta2ns(50, &comparator) + 1;
+	comparator.cpumask = cpumask_of(0);
 
-	ret = clocksource_register(&clocksource_avr32);
-	if (ret)
-		printk(KERN_ERR
-		       "timer: could not register clocksource: %d\n", ret);
+	sysreg_write(COMPARE, 0);
+	timer_irqaction.dev_id = &comparator;
 
 	ret = setup_irq(0, &timer_irqaction);
 	if (ret)
-		printk("timer: could not request IRQ 0: %d\n", ret);
-}
-
-static struct sysdev_class timer_class = {
-	set_kset_name("timer"),
-};
+		pr_debug("timer: could not request IRQ 0: %d\n", ret);
+	else {
+		clockevents_register_device(&comparator);
 
-static struct sys_device timer_device = {
-	.id	= 0,
-	.cls	= &timer_class,
-};
-
-static int __init init_timer_sysfs(void)
-{
-	int err = sysdev_class_register(&timer_class);
-	if (!err)
-		err = sysdev_register(&timer_device);
-	return err;
+		pr_info("%s: irq 0, %lu.%03lu MHz\n", comparator.name,
+				((counter_hz + 500) / 1000) / 1000,
+				((counter_hz + 500) / 1000) % 1000);
+	}
 }
-
-device_initcall(init_timer_sysfs);