1 files changed, 164 insertions, 0 deletions

diff --git a/arch/arm/mach-pxa/time.c b/arch/arm/mach-pxa/time.c
new file mode 100644
index 000000000000..473fb6173f72
--- /dev/null
+++ b/arch/arm/mach-pxa/time.c
@@ -0,0 +1,164 @@
+/*
+ * arch/arm/mach-pxa/time.c
+ *
+ * Author:      Nicolas Pitre
+ * Created:     Jun 15, 2001
+ * Copyright:   MontaVista Software Inc.
+ *
+ * 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/config.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/time.h>
+#include <linux/signal.h>
+#include <linux/errno.h>
+#include <linux/sched.h>
+
+#include <asm/system.h>
+#include <asm/hardware.h>
+#include <asm/io.h>
+#include <asm/leds.h>
+#include <asm/irq.h>
+#include <asm/mach/irq.h>
+#include <asm/mach/time.h>
+#include <asm/arch/pxa-regs.h>
+
+
+static inline unsigned long pxa_get_rtc_time(void)
+{
+        return RCNR;
+}
+
+static int pxa_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 pxa_gettimeoffset (void)
+{
+        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;
+
+        /* don't get fooled by the workaround in pxa_timer_interrupt() */
+        if (elapsed <= 0)
+                return 0;
+
+        /* Now convert them to usec */
+        usec = (unsigned long)(elapsed * (tick_nsec / 1000))/LATCH;
+
+        return usec;
+}
+
+static irqreturn_t
+pxa_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+{
+        int next_match;
+
+        write_seqlock(&xtime_lock);
+
+        /* 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.
+         *
+         * HACK ALERT: it seems that the PXA timer regs aren't updated right
+         * away in all cases when a write occurs.  We therefore compare with
+         * 8 instead of 0 in the while() condition below to avoid missing a
+         * match if OSCR has already reached the next OSMR value.
+         * Experience has shown that up to 6 ticks are needed to work around
+         * this problem, but let's use 8 to be conservative.  Note that this
+         * affect things only when the timer IRQ has been delayed by nearly
+         * exactly one tick period which should be a pretty rare event.
+         */
+        do {
+                timer_tick(regs);
+                OSSR = OSSR_M0;  /* Clear match on timer 0 */
+                next_match = (OSMR0 += LATCH);
+        } while( (signed long)(next_match - OSCR) <= 8 );
+
+        write_sequnlock(&xtime_lock);
+
+        return IRQ_HANDLED;
+}
+
+static struct irqaction pxa_timer_irq = {
+        .name           = "PXA Timer Tick",
+        .flags          = SA_INTERRUPT,
+        .handler        = pxa_timer_interrupt
+};
+
+static void __init pxa_timer_init(void)
+{
+        struct timespec tv;
+
+        set_rtc = pxa_set_rtc;
+
+        tv.tv_nsec = 0;
+        tv.tv_sec = pxa_get_rtc_time();
+        do_settimeofday(&tv);
+
+        OSMR0 = 0;              /* set initial match at 0 */
+        OSSR = 0xf;             /* clear status on all timers */
+        setup_irq(IRQ_OST0, &pxa_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
+static unsigned long osmr[4], oier;
+
+static void pxa_timer_suspend(void)
+{
+        osmr[0] = OSMR0;
+        osmr[1] = OSMR1;
+        osmr[2] = OSMR2;
+        osmr[3] = OSMR3;
+        oier = OIER;
+}
+
+static void pxa_timer_resume(void)
+{
+        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 pxa_timer_suspend NULL
+#define pxa_timer_resume NULL
+#endif
+
+struct sys_timer pxa_timer = {
+        .init           = pxa_timer_init,
+        .suspend        = pxa_timer_suspend,
+        .resume         = pxa_timer_resume,
+        .offset         = pxa_gettimeoffset,
+};