1 files changed, 159 insertions, 0 deletions
diff --git a/arch/arm/mach-sa1100/time.c b/arch/arm/mach-sa1100/time.c
new file mode 100644
index 0000000..19b0c0f
--- /dev/null
+++ b/arch/arm/mach-sa1100/time.c
@@ -0,0 +1,159 @@
+/*
+ * linux/arch/arm/mach-sa1100/time.c
+ *
+ * Copyright (C) 1998 Deborah Wallach.
+ * Twiddles  (C) 1999 	Hugo Fiennes <hugo@empeg.com>
+ * 
+ * 2000/03/29 (C) Nicolas Pitre <nico@cam.org>
+ *	Rewritten: big cleanup, much simpler, better HZ accuracy.
+ *
+ */
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/timex.h>
+#include <linux/signal.h>
+
+#include <asm/mach/time.h>
+#include <asm/hardware.h>
+
+#define RTC_DEF_DIVIDER		(32768 - 1)
+#define RTC_DEF_TRIM            0
+
+static unsigned long __init sa1100_get_rtc_time(void)
+{
+	/*
+	 * According to the manual we should be able to let RTTR be zero
+	 * and then a default diviser for a 32.768KHz clock is used.
+	 * Apparently this doesn't work, at least for my SA1110 rev 5.
+	 * If the clock divider is uninitialized then reset it to the
+	 * default value to get the 1Hz clock.
+	 */
+	if (RTTR == 0) {
+		RTTR = RTC_DEF_DIVIDER + (RTC_DEF_TRIM << 16);
+		printk(KERN_WARNING "Warning: uninitialized Real Time Clock\n");
+		/* The current RTC value probably doesn't make sense either */
+		RCNR = 0;
+		return 0;
+	}
+	return RCNR;
+}
+
+static int sa1100_set_rtc(void)
+{
+	unsigned long current_time = xtime.tv_sec;
+
+	if (RTSR & RTSR_ALE) {
+		/* make sure not to forward the clock over an alarm */
+		unsigned long alarm = RTAR;
+		if (current_time >= alarm && alarm >= RCNR)
+			return -ERESTARTSYS;
+	}
+	RCNR = current_time;
+	return 0;
+}
+
+/* IRQs are disabled before entering here from do_gettimeofday() */
+static unsigned long sa1100_gettimeoffset (void)
+{
+	unsigned long ticks_to_match, elapsed, usec;
+
+	/* Get ticks before next timer match */
+	ticks_to_match = OSMR0 - OSCR;
+
+	/* We need elapsed ticks since last match */
+	elapsed = LATCH - ticks_to_match;
+
+	/* Now convert them to usec */
+	usec = (unsigned long)(elapsed * (tick_nsec / 1000))/LATCH;
+
+	return usec;
+}
+
+/*
+ * We will be entered with IRQs enabled.
+ *
+ * Loop until we get ahead of the free running timer.
+ * This ensures an exact clock tick count and time accuracy.
+ * IRQs are disabled inside the loop to ensure coherence between
+ * lost_ticks (updated in do_timer()) and the match reg value, so we
+ * can use do_gettimeofday() from interrupt handlers.
+ */
+static irqreturn_t
+sa1100_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+{
+	unsigned int next_match;
+
+	write_seqlock(&xtime_lock);
+
+	do {
+		timer_tick(regs);
+		OSSR = OSSR_M0;  /* Clear match on timer 0 */
+		next_match = (OSMR0 += LATCH);
+	} while ((signed long)(next_match - OSCR) <= 0);
+
+	write_sequnlock(&xtime_lock);
+
+	return IRQ_HANDLED;
+}
+
+static struct irqaction sa1100_timer_irq = {
+	.name		= "SA11xx Timer Tick",
+	.flags		= SA_INTERRUPT,
+	.handler	= sa1100_timer_interrupt
+};
+
+static void __init sa1100_timer_init(void)
+{
+	struct timespec tv;
+
+	set_rtc = sa1100_set_rtc;
+
+	tv.tv_nsec = 0;
+	tv.tv_sec = sa1100_get_rtc_time();
+	do_settimeofday(&tv);
+
+	OSMR0 = 0;		/* set initial match at 0 */
+	OSSR = 0xf;		/* clear status on all timers */
+	setup_irq(IRQ_OST0, &sa1100_timer_irq);
+	OIER |= OIER_E0;	/* enable match on timer 0 to cause interrupts */
+	OSCR = 0;		/* initialize free-running timer, force first match */
+}
+
+#ifdef CONFIG_PM
+unsigned long osmr[4], oier;
+
+static void sa1100_timer_suspend(void)
+{
+	osmr[0] = OSMR0;
+	osmr[1] = OSMR1;
+	osmr[2] = OSMR2;
+	osmr[3] = OSMR3;
+	oier = OIER;
+}
+
+static void sa1100_timer_resume(void)
+{
+	OSSR = 0x0f;
+	OSMR0 = osmr[0];
+	OSMR1 = osmr[1];
+	OSMR2 = osmr[2];
+	OSMR3 = osmr[3];
+	OIER = oier;
+
+	/*
+	 * OSMR0 is the system timer: make sure OSCR is sufficiently behind
+	 */
+	OSCR = OSMR0 - LATCH;
+}
+#else
+#define sa1100_timer_suspend NULL
+#define sa1100_timer_resume NULL
+#endif
+
+struct sys_timer sa1100_timer = {
+	.init		= sa1100_timer_init,
+	.suspend	= sa1100_timer_suspend,
+	.resume		= sa1100_timer_resume,
+	.offset		= sa1100_gettimeoffset,
+};