Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6

[linux-2.6] / include / asm-sparc / atomic.h

diff --git a/include/asm-sparc/atomic.h b/include/asm-sparc/atomic.h
index 62bec7ad271c496e81a8f2d95d4f4377cb16c952..bdca5416d8b0a74dd998f3cbb8517839cc8b52d1 100644 (file)
--- a/include/asm-sparc/atomic.h
+++ b/include/asm-sparc/atomic.h
@@ -2,6 +2,7 @@
  *
  * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
  * Copyright (C) 2000 Anton Blanchard (anton@linuxcare.com.au)
+ * Copyright (C) 2007 Kyle McMartin (kyle@parisc-linux.org)
  *
  * Additions by Keith M Wesolowski (wesolows@foobazco.org) based
  * on asm-parisc/atomic.h Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>.
@@ -10,16 +11,53 @@
 #ifndef __ARCH_SPARC_ATOMIC__
 #define __ARCH_SPARC_ATOMIC__
 
-#include <linux/config.h>
+#include <linux/types.h>
 
 typedef struct { volatile int counter; } atomic_t;
 
 #ifdef __KERNEL__
 
+/* Emulate cmpxchg() the same way we emulate atomics,
+ * by hashing the object address and indexing into an array
+ * of spinlocks to get a bit of performance...
+ *
+ * See arch/sparc/lib/atomic32.c for implementation.
+ *
+ * Cribbed from <asm-parisc/atomic.h>
+ */
+#define __HAVE_ARCH_CMPXCHG    1
+
+/* bug catcher for when unsupported size is used - won't link */
+extern void __cmpxchg_called_with_bad_pointer(void);
+/* we only need to support cmpxchg of a u32 on sparc */
+extern unsigned long __cmpxchg_u32(volatile u32 *m, u32 old, u32 new_);
+
+/* don't worry...optimizer will get rid of most of this */
+static __inline__ unsigned long
+__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size)
+{
+       switch(size) {
+       case 4:
+               return __cmpxchg_u32((u32 *)ptr, (u32)old, (u32)new_);
+       default:
+               __cmpxchg_called_with_bad_pointer();
+               break;
+       }
+       return old;
+}
+
+#define cmpxchg(ptr,o,n) ({                                            \
+       __typeof__(*(ptr)) _o_ = (o);                                   \
+       __typeof__(*(ptr)) _n_ = (n);                                   \
+       (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_,       \
+                       (unsigned long)_n_, sizeof(*(ptr)));            \
+})
+
 #define ATOMIC_INIT(i)  { (i) }
 
 extern int __atomic_add_return(int, atomic_t *);
 extern int atomic_cmpxchg(atomic_t *, int, int);
+#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
 extern int atomic_add_unless(atomic_t *, int, int);
 extern void atomic_set(atomic_t *, int);
 
@@ -159,4 +197,5 @@ static inline int __atomic24_sub(int i, atomic24_t *v)
 
 #endif /* !(__KERNEL__) */
 
+#include <asm-generic/atomic.h>
 #endif /* !(__ARCH_SPARC_ATOMIC__) */