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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/alpha/lib/udelay.c
downloadconfigs-2.6.12-rc2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/alpha/lib/udelay.c')
-rw-r--r--arch/alpha/lib/udelay.c55
1 files changed, 55 insertions, 0 deletions
diff --git a/arch/alpha/lib/udelay.c b/arch/alpha/lib/udelay.c
new file mode 100644
index 00000000000..1c879bbce41
--- /dev/null
+++ b/arch/alpha/lib/udelay.c
@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 1993, 2000 Linus Torvalds
+ *
+ * Delay routines, using a pre-computed "loops_per_jiffy" value.
+ */
+
+#include <linux/config.h>
+#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);