Merge ../linux-2.6/

Conflicts:

	drivers/scsi/aacraid/comminit.c

Fixed up by removing the now renamed CONFIG_IOMMU option from
aacraid

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 118 insertions, 0 deletions

diff --git a/arch/i386/kernel/i8253.c b/arch/i386/kernel/i8253.c
new file mode 100644
index 000000000000..477b24daff53
--- /dev/null
+++ b/arch/i386/kernel/i8253.c
@@ -0,0 +1,118 @@
+/*
+ * i8253.c  8253/PIT functions
+ *
+ */
+#include <linux/clocksource.h>
+#include <linux/spinlock.h>
+#include <linux/jiffies.h>
+#include <linux/sysdev.h>
+#include <linux/module.h>
+#include <linux/init.h>
+
+#include <asm/smp.h>
+#include <asm/delay.h>
+#include <asm/i8253.h>
+#include <asm/io.h>
+
+#include "io_ports.h"
+
+DEFINE_SPINLOCK(i8253_lock);
+EXPORT_SYMBOL(i8253_lock);
+
+void setup_pit_timer(void)
+{
+        unsigned long flags;
+
+        spin_lock_irqsave(&i8253_lock, flags);
+        outb_p(0x34,PIT_MODE);          /* binary, mode 2, LSB/MSB, ch 0 */
+        udelay(10);
+        outb_p(LATCH & 0xff , PIT_CH0); /* LSB */
+        udelay(10);
+        outb(LATCH >> 8 , PIT_CH0);     /* MSB */
+        spin_unlock_irqrestore(&i8253_lock, flags);
+}
+
+/*
+ * Since the PIT overflows every tick, its not very useful
+ * to just read by itself. So use jiffies to emulate a free
+ * running counter:
+ */
+static cycle_t pit_read(void)
+{
+        unsigned long flags;
+        int count;
+        u32 jifs;
+        static int old_count;
+        static u32 old_jifs;
+
+        spin_lock_irqsave(&i8253_lock, flags);
+        /*
+         * Although our caller may have the read side of xtime_lock,
+         * this is now a seqlock, and we are cheating in this routine
+         * by having side effects on state that we cannot undo if
+         * there is a collision on the seqlock and our caller has to
+         * retry.  (Namely, old_jifs and old_count.)  So we must treat
+         * jiffies as volatile despite the lock.  We read jiffies
+         * before latching the timer count to guarantee that although
+         * the jiffies value might be older than the count (that is,
+         * the counter may underflow between the last point where
+         * jiffies was incremented and the point where we latch the
+         * count), it cannot be newer.
+         */
+        jifs = jiffies;
+        outb_p(0x00, PIT_MODE); /* latch the count ASAP */
+        count = inb_p(PIT_CH0); /* read the latched count */
+        count |= inb_p(PIT_CH0) << 8;
+
+        /* VIA686a test code... reset the latch if count > max + 1 */
+        if (count > LATCH) {
+                outb_p(0x34, PIT_MODE);
+                outb_p(LATCH & 0xff, PIT_CH0);
+                outb(LATCH >> 8, PIT_CH0);
+                count = LATCH - 1;
+        }
+
+        /*
+         * It's possible for count to appear to go the wrong way for a
+         * couple of reasons:
+         *
+         *  1. The timer counter underflows, but we haven't handled the
+         *     resulting interrupt and incremented jiffies yet.
+         *  2. Hardware problem with the timer, not giving us continuous time,
+         *     the counter does small "jumps" upwards on some Pentium systems,
+         *     (see c't 95/10 page 335 for Neptun bug.)
+         *
+         * Previous attempts to handle these cases intelligently were
+         * buggy, so we just do the simple thing now.
+         */
+        if (count > old_count && jifs == old_jifs) {
+                count = old_count;
+        }
+        old_count = count;
+        old_jifs = jifs;
+
+        spin_unlock_irqrestore(&i8253_lock, flags);
+
+        count = (LATCH - 1) - count;
+
+        return (cycle_t)(jifs * LATCH) + count;
+}
+
+static struct clocksource clocksource_pit = {
+        .name   = "pit",
+        .rating = 110,
+        .read   = pit_read,
+        .mask   = CLOCKSOURCE_MASK(32),
+        .mult   = 0,
+        .shift  = 20,
+};
+
+static int __init init_pit_clocksource(void)
+{
+        if (num_possible_cpus() > 4) /* PIT does not scale! */
+                return 0;
+
+        clocksource_pit.mult = clocksource_hz2mult(CLOCK_TICK_RATE, 20);
+        return clocksource_register(&clocksource_pit);
+}
+module_init(init_pit_clocksource);