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authorThomas Gleixner <tglx@linutronix.de>2007-10-11 11:16:33 +0200
committerThomas Gleixner <tglx@linutronix.de>2007-10-11 11:16:33 +0200
commit44f0257fc316ff4b33aa3438dd8d891b7d6d72b9 (patch)
treec1a9a571db37d631489f18e1dfe5554874b19027 /arch/x86/lib/delay_32.c
parentda957e111bb0c189a4a3bf8a00caaecb59ed94ca (diff)
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i386: move lib
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/lib/delay_32.c')
-rw-r--r--arch/x86/lib/delay_32.c103
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 00000000000..f6edb11364d
--- /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);