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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /arch/alpha/lib/udelay.c
Initial import
Diffstat (limited to 'arch/alpha/lib/udelay.c')
-rw-r--r--arch/alpha/lib/udelay.c54
1 files changed, 54 insertions, 0 deletions
diff --git a/arch/alpha/lib/udelay.c b/arch/alpha/lib/udelay.c
new file mode 100644
index 000000000..69d52aa37
--- /dev/null
+++ b/arch/alpha/lib/udelay.c
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 1993, 2000 Linus Torvalds
+ *
+ * Delay routines, using a pre-computed "loops_per_jiffy" value.
+ */
+
+#include <linux/module.h>
+#include <linux/sched.h> /* for udelay's use of smp_processor_id */
+#include <asm/param.h>
+#include <asm/smp.h>
+#include <linux/delay.h>
+
+/*
+ * Use only for very small delays (< 1 msec).
+ *
+ * The active part of our cycle counter is only 32-bits wide, and
+ * we're treating the difference between two marks as signed. On
+ * a 1GHz box, that's about 2 seconds.
+ */
+
+void
+__delay(int loops)
+{
+ int tmp;
+ __asm__ __volatile__(
+ " rpcc %0\n"
+ " addl %1,%0,%1\n"
+ "1: rpcc %0\n"
+ " subl %1,%0,%0\n"
+ " bgt %0,1b"
+ : "=&r" (tmp), "=r" (loops) : "1"(loops));
+}
+
+#ifdef CONFIG_SMP
+#define LPJ cpu_data[smp_processor_id()].loops_per_jiffy
+#else
+#define LPJ loops_per_jiffy
+#endif
+
+void
+udelay(unsigned long usecs)
+{
+ usecs *= (((unsigned long)HZ << 32) / 1000000) * LPJ;
+ __delay((long)usecs >> 32);
+}
+EXPORT_SYMBOL(udelay);
+
+void
+ndelay(unsigned long nsecs)
+{
+ nsecs *= (((unsigned long)HZ << 32) / 1000000000) * LPJ;
+ __delay((long)nsecs >> 32);
+}
+EXPORT_SYMBOL(ndelay);