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Diffstat (limited to 'arch/i386/lib/delay.c')
-rw-r--r--arch/i386/lib/delay.c65
1 files changed, 57 insertions, 8 deletions
diff --git a/arch/i386/lib/delay.c b/arch/i386/lib/delay.c
index c49a6acbee5..3c0714c4b66 100644
--- a/arch/i386/lib/delay.c
+++ b/arch/i386/lib/delay.c
@@ -10,43 +10,92 @@
* we have to worry about.
*/
+#include <linux/module.h>
#include <linux/config.h>
#include <linux/sched.h>
#include <linux/delay.h>
-#include <linux/module.h>
+
#include <asm/processor.h>
#include <asm/delay.h>
#include <asm/timer.h>
#ifdef CONFIG_SMP
-#include <asm/smp.h>
+# include <asm/smp.h>
#endif
-extern struct timer_opts* timer;
+/* 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)
{
- cur_timer->delay(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);
+ :"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) */
+ __const_udelay(usecs * 0x000010c7); /* 2**32 / 1000000 (rounded up) */
}
void __ndelay(unsigned long nsecs)
{
- __const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */
+ __const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */
}
EXPORT_SYMBOL(__delay);