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-rw-r--r--include/asm-i386/mach-default/do_timer.h85
1 files changed, 85 insertions, 0 deletions
diff --git a/include/asm-i386/mach-default/do_timer.h b/include/asm-i386/mach-default/do_timer.h
new file mode 100644
index 000000000000..03dd13a48a8c
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+++ b/include/asm-i386/mach-default/do_timer.h
@@ -0,0 +1,85 @@
+/* defines for inline arch setup functions */
+
+#include <asm/apic.h>
+
+/**
+ * do_timer_interrupt_hook - hook into timer tick
+ * @regs: standard registers from interrupt
+ *
+ * Description:
+ * This hook is called immediately after the timer interrupt is ack'd.
+ * It's primary purpose is to allow architectures that don't possess
+ * individual per CPU clocks (like the CPU APICs supply) to broadcast the
+ * timer interrupt as a means of triggering reschedules etc.
+ **/
+
+static inline void do_timer_interrupt_hook(struct pt_regs *regs)
+{
+ do_timer(regs);
+#ifndef CONFIG_SMP
+ update_process_times(user_mode(regs));
+#endif
+/*
+ * In the SMP case we use the local APIC timer interrupt to do the
+ * profiling, except when we simulate SMP mode on a uniprocessor
+ * system, in that case we have to call the local interrupt handler.
+ */
+#ifndef CONFIG_X86_LOCAL_APIC
+ profile_tick(CPU_PROFILING, regs);
+#else
+ if (!using_apic_timer)
+ smp_local_timer_interrupt(regs);
+#endif
+}
+
+
+/* you can safely undefine this if you don't have the Neptune chipset */
+
+#define BUGGY_NEPTUN_TIMER
+
+/**
+ * do_timer_overflow - process a detected timer overflow condition
+ * @count: hardware timer interrupt count on overflow
+ *
+ * Description:
+ * This call is invoked when the jiffies count has not incremented but
+ * the hardware timer interrupt has. It means that a timer tick interrupt
+ * came along while the previous one was pending, thus a tick was missed
+ **/
+static inline int do_timer_overflow(int count)
+{
+ int i;
+
+ spin_lock(&i8259A_lock);
+ /*
+ * This is tricky when I/O APICs are used;
+ * see do_timer_interrupt().
+ */
+ i = inb(0x20);
+ spin_unlock(&i8259A_lock);
+
+ /* assumption about timer being IRQ0 */
+ if (i & 0x01) {
+ /*
+ * We cannot detect lost timer interrupts ...
+ * well, that's why we call them lost, don't we? :)
+ * [hmm, on the Pentium and Alpha we can ... sort of]
+ */
+ count -= LATCH;
+ } else {
+#ifdef BUGGY_NEPTUN_TIMER
+ /*
+ * for the Neptun bug we know that the 'latch'
+ * command doesn't latch the high and low value
+ * of the counter atomically. Thus we have to
+ * substract 256 from the counter
+ * ... funny, isnt it? :)
+ */
+
+ count -= 256;
+#else
+ printk("do_slow_gettimeoffset(): hardware timer problem?\n");
+#endif
+ }
+ return count;
+}