Import of Linux/MIPS 2.1.14

1 files changed, 54 insertions, 0 deletions

diff --git a/include/asm-sparc/smpprim.h b/include/asm-sparc/smpprim.h
new file mode 100644
index 000000000..9b9c28ed7
--- /dev/null
+++ b/include/asm-sparc/smpprim.h
@@ -0,0 +1,54 @@
+/*  $Id: smpprim.h,v 1.5 1996/08/29 09:48:49 davem Exp $
+ *  smpprim.h:  SMP locking primitives on the Sparc
+ *
+ *  God knows we won't be actually using this code for some time
+ *  but I thought I'd write it since I knew how.
+ *
+ *  Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
+ */
+
+#ifndef __SPARC_SMPPRIM_H
+#define __SPARC_SMPPRIM_H
+
+/* Test and set the unsigned byte at ADDR to 1.  Returns the previous
+ * value.  On the Sparc we use the ldstub instruction since it is
+ * atomic.
+ */
+
+extern __inline__ __volatile__ char test_and_set(void *addr)
+{
+	char state = 0;
+
+	__asm__ __volatile__("ldstub [%0], %1         ! test_and_set\n\t"
+			     "=r" (addr), "=r" (state) :
+			     "0" (addr), "1" (state) : "memory");
+
+	return state;
+}
+
+/* Initialize a spin-lock. */
+extern __inline__ __volatile__ smp_initlock(void *spinlock)
+{
+	/* Unset the lock. */
+	*((unsigned char *) spinlock) = 0;
+
+	return;
+}
+
+/* This routine spins until it acquires the lock at ADDR. */
+extern __inline__ __volatile__ smp_lock(void *addr)
+{
+	while(test_and_set(addr) == 0xff)
+		;
+
+	/* We now have the lock */
+	return;
+}
+
+/* This routine releases the lock at ADDR. */
+extern __inline__ __volatile__ smp_unlock(void *addr)
+{
+	*((unsigned char *) addr) = 0;
+}
+
+#endif /* !(__SPARC_SMPPRIM_H) */