1 files changed, 103 insertions, 0 deletions
diff --git a/arch/x86/lib/delay_32.c b/arch/x86/lib/delay_32.c
new file mode 100644
index 000000000000..f6edb11364df
--- /dev/null
+++ b/arch/x86/lib/delay_32.c
@@ -0,0 +1,103 @@
+/*
+ *	Precise Delay Loops for i386
+ *
+ *	Copyright (C) 1993 Linus Torvalds
+ *	Copyright (C) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
+ *
+ *	The __delay function must _NOT_ be inlined as its execution time
+ *	depends wildly on alignment on many x86 processors. The additional
+ *	jump magic is needed to get the timing stable on all the CPU's
+ *	we have to worry about.
+ */
+
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/delay.h>
+
+#include <asm/processor.h>
+#include <asm/delay.h>
+#include <asm/timer.h>
+
+#ifdef CONFIG_SMP
+# include <asm/smp.h>
+#endif
+
+/* simple loop based delay: */
+static void delay_loop(unsigned long loops)
+{
+	int d0;
+
+	__asm__ __volatile__(
+		"\tjmp 1f\n"
+		".align 16\n"
+		"1:\tjmp 2f\n"
+		".align 16\n"
+		"2:\tdecl %0\n\tjns 2b"
+		:"=&a" (d0)
+		:"0" (loops));
+}
+
+/* TSC based delay: */
+static void delay_tsc(unsigned long loops)
+{
+	unsigned long bclock, now;
+
+	rdtscl(bclock);
+	do {
+		rep_nop();
+		rdtscl(now);
+	} while ((now-bclock) < loops);
+}
+
+/*
+ * Since we calibrate only once at boot, this
+ * function should be set once at boot and not changed
+ */
+static void (*delay_fn)(unsigned long) = delay_loop;
+
+void use_tsc_delay(void)
+{
+	delay_fn = delay_tsc;
+}
+
+int read_current_timer(unsigned long *timer_val)
+{
+	if (delay_fn == delay_tsc) {
+		rdtscl(*timer_val);
+		return 0;
+	}
+	return -1;
+}
+
+void __delay(unsigned long loops)
+{
+	delay_fn(loops);
+}
+
+inline void __const_udelay(unsigned long xloops)
+{
+	int d0;
+
+	xloops *= 4;
+	__asm__("mull %0"
+		:"=d" (xloops), "=&a" (d0)
+		:"1" (xloops), "0"
+		(cpu_data[raw_smp_processor_id()].loops_per_jiffy * (HZ/4)));
+
+	__delay(++xloops);
+}
+
+void __udelay(unsigned long usecs)
+{
+	__const_udelay(usecs * 0x000010c7); /* 2**32 / 1000000 (rounded up) */
+}
+
+void __ndelay(unsigned long nsecs)
+{
+	__const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */
+}
+
+EXPORT_SYMBOL(__delay);
+EXPORT_SYMBOL(__const_udelay);
+EXPORT_SYMBOL(__udelay);
+EXPORT_SYMBOL(__ndelay);