1 files changed, 117 insertions, 0 deletions
diff --git a/arch/xtensa/kernel/time.c b/arch/xtensa/kernel/time.c
new file mode 100644
index 00000000..ac62f9cf
--- /dev/null
+++ b/arch/xtensa/kernel/time.c
@@ -0,0 +1,117 @@
+/*
+ * arch/xtensa/kernel/time.c
+ *
+ * Timer and clock support.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2005 Tensilica Inc.
+ *
+ * Chris Zankel <chris@zankel.net>
+ */
+
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/time.h>
+#include <linux/clocksource.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/profile.h>
+#include <linux/delay.h>
+
+#include <asm/timex.h>
+#include <asm/platform.h>
+
+#ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT
+unsigned long ccount_per_jiffy;		/* per 1/HZ */
+unsigned long nsec_per_ccount;		/* nsec per ccount increment */
+#endif
+
+static cycle_t ccount_read(void)
+{
+	return (cycle_t)get_ccount();
+}
+
+static struct clocksource ccount_clocksource = {
+	.name = "ccount",
+	.rating = 200,
+	.read = ccount_read,
+	.mask = CLOCKSOURCE_MASK(32),
+};
+
+static irqreturn_t timer_interrupt(int irq, void *dev_id);
+static struct irqaction timer_irqaction = {
+	.handler =	timer_interrupt,
+	.flags =	IRQF_DISABLED,
+	.name =		"timer",
+};
+
+void __init time_init(void)
+{
+#ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT
+	printk("Calibrating CPU frequency ");
+	platform_calibrate_ccount();
+	printk("%d.%02d MHz\n", (int)ccount_per_jiffy/(1000000/HZ),
+			(int)(ccount_per_jiffy/(10000/HZ))%100);
+#endif
+	clocksource_register_hz(&ccount_clocksource, CCOUNT_PER_JIFFY * HZ);
+
+	/* Initialize the linux timer interrupt. */
+
+	setup_irq(LINUX_TIMER_INT, &timer_irqaction);
+	set_linux_timer(get_ccount() + CCOUNT_PER_JIFFY);
+}
+
+/*
+ * The timer interrupt is called HZ times per second.
+ */
+
+irqreturn_t timer_interrupt (int irq, void *dev_id)
+{
+
+	unsigned long next;
+
+	next = get_linux_timer();
+
+again:
+	while ((signed long)(get_ccount() - next) > 0) {
+
+		profile_tick(CPU_PROFILING);
+#ifndef CONFIG_SMP
+		update_process_times(user_mode(get_irq_regs()));
+#endif
+
+		xtime_update(1); /* Linux handler in kernel/time/timekeeping */
+
+		/* Note that writing CCOMPARE clears the interrupt. */
+
+		next += CCOUNT_PER_JIFFY;
+		set_linux_timer(next);
+	}
+
+	/* Allow platform to do something useful (Wdog). */
+
+	platform_heartbeat();
+
+	/* Make sure we didn't miss any tick... */
+
+	if ((signed long)(get_ccount() - next) > 0)
+		goto again;
+
+	return IRQ_HANDLED;
+}
+
+#ifndef CONFIG_GENERIC_CALIBRATE_DELAY
+void __cpuinit calibrate_delay(void)
+{
+	loops_per_jiffy = CCOUNT_PER_JIFFY;
+	printk("Calibrating delay loop (skipped)... "
+	       "%lu.%02lu BogoMIPS preset\n",
+	       loops_per_jiffy/(1000000/HZ),
+	       (loops_per_jiffy/(10000/HZ)) % 100);
+}
+#endif