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 00000000000..03dd13a48a8
--- /dev/null
+++ 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;
+}