Initial import

1 files changed, 160 insertions, 0 deletions

diff --git a/arch/avr32/kernel/time.c b/arch/avr32/kernel/time.c
new file mode 100644
index 000000000..d0f771be9
--- /dev/null
+++ b/arch/avr32/kernel/time.c
@@ -0,0 +1,160 @@
+/*
+ * 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/clockchips.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/time.h>
+#include <linux/cpu.h>
+
+#include <asm/sysreg.h>
+
+#include <mach/pm.h>
+
+
+static cycle_t read_cycle_count(struct clocksource *cs)
+{
+	return (cycle_t)sysreg_read(COUNT);
+}
+
+/*
+ * 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 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 clock_event_device *evdev = dev_id;
+
+	if (unlikely(!(intc_get_pending(0) & 1)))
+		return IRQ_NONE;
+
+	/*
+	 * Disable the interrupt until the clockevent subsystem
+	 * reprograms it.
+	 */
+	sysreg_write(COMPARE, 0);
+
+	evdev->event_handler(evdev);
+	return IRQ_HANDLED;
+}
+
+static struct irqaction timer_irqaction = {
+	.handler	= timer_interrupt,
+	/* Oprofile uses the same irq as the timer, so allow it to be shared */
+	.flags		= IRQF_TIMER | IRQF_SHARED,
+	.name		= "avr32_comparator",
+};
+
+static int comparator_next_event(unsigned long delta,
+		struct clock_event_device *evdev)
+{
+	unsigned long	flags;
+
+	raw_local_irq_save(flags);
+
+	/* 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);
+
+	raw_local_irq_restore(flags);
+
+	return 0;
+}
+
+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();
+	}
+}
+
+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,
+};
+
+void read_persistent_clock(struct timespec *ts)
+{
+	ts->tv_sec = mktime(2007, 1, 1, 0, 0, 0);
+	ts->tv_nsec = 0;
+}
+
+void __init time_init(void)
+{
+	unsigned long counter_hz;
+	int ret;
+
+	/* 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);
+
+	/* 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);
+
+	sysreg_write(COMPARE, 0);
+	timer_irqaction.dev_id = &comparator;
+
+	ret = setup_irq(0, &timer_irqaction);
+	if (ret)
+		pr_debug("timer: could not request IRQ 0: %d\n", ret);
+	else {
+		clockevents_register_device(&comparator);
+
+		pr_info("%s: irq 0, %lu.%03lu MHz\n", comparator.name,
+				((counter_hz + 500) / 1000) / 1000,
+				((counter_hz + 500) / 1000) % 1000);
+	}
+}