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);