Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 94 insertions, 0 deletions

diff --git a/arch/arm/mach-footbridge/isa-timer.c b/arch/arm/mach-footbridge/isa-timer.c
new file mode 100644
index 000000000000..a4fefa0bb5a1
--- /dev/null
+++ b/arch/arm/mach-footbridge/isa-timer.c
@@ -0,0 +1,94 @@
+/*
+ *  linux/arch/arm/mach-footbridge/isa-timer.c
+ *
+ *  Copyright (C) 1998 Russell King.
+ *  Copyright (C) 1998 Phil Blundell
+ */
+#include <linux/init.h>
+#include <linux/interrupt.h>
+
+#include <asm/io.h>
+#include <asm/irq.h>
+
+#include <asm/mach/time.h>
+
+#include "common.h"
+
+/*
+ * ISA timer tick support
+ */
+#define mSEC_10_from_14 ((14318180 + 100) / 200)
+
+static unsigned long isa_gettimeoffset(void)
+{
+        int count;
+
+        static int count_p = (mSEC_10_from_14/6);    /* for the first call after boot */
+        static unsigned long jiffies_p = 0;
+
+        /*
+         * cache volatile jiffies temporarily; we have IRQs turned off. 
+         */
+        unsigned long jiffies_t;
+
+        /* timer count may underflow right here */
+        outb_p(0x00, 0x43);     /* latch the count ASAP */
+
+        count = inb_p(0x40);    /* read the latched count */
+
+        /*
+         * We do this guaranteed double memory access instead of a _p 
+         * postfix in the previous port access. Wheee, hackady hack
+         */
+        jiffies_t = jiffies;
+
+        count |= inb_p(0x40) << 8;
+
+        /* Detect timer underflows.  If we haven't had a timer tick since 
+           the last time we were called, and time is apparently going
+           backwards, the counter must have wrapped during this routine. */
+        if ((jiffies_t == jiffies_p) && (count > count_p))
+                count -= (mSEC_10_from_14/6);
+        else
+                jiffies_p = jiffies_t;
+
+        count_p = count;
+
+        count = (((mSEC_10_from_14/6)-1) - count) * (tick_nsec / 1000);
+        count = (count + (mSEC_10_from_14/6)/2) / (mSEC_10_from_14/6);
+
+        return count;
+}
+
+static irqreturn_t
+isa_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+{
+        write_seqlock(&xtime_lock);
+        timer_tick(regs);
+        write_sequnlock(&xtime_lock);
+        return IRQ_HANDLED;
+}
+
+static struct irqaction isa_timer_irq = {
+        .name           = "ISA timer tick",
+        .handler        = isa_timer_interrupt,
+        .flags          = SA_INTERRUPT,
+};
+
+static void __init isa_timer_init(void)
+{
+        isa_rtc_init();
+
+        /* enable PIT timer */
+        /* set for periodic (4) and LSB/MSB write (0x30) */
+        outb(0x34, 0x43);
+        outb((mSEC_10_from_14/6) & 0xFF, 0x40);
+        outb((mSEC_10_from_14/6) >> 8, 0x40);
+
+        setup_irq(IRQ_ISA_TIMER, &isa_timer_irq);
+}
+
+struct sys_timer isa_timer = {
+        .init           = isa_timer_init,
+        .offset         = isa_gettimeoffset,
+};