1 files changed, 209 insertions, 0 deletions

diff --git a/include/asm-powerpc/atomic.h b/include/asm-powerpc/atomic.h
new file mode 100644
index 000000000000..ed4b345ed75d
--- /dev/null
+++ b/include/asm-powerpc/atomic.h
@@ -0,0 +1,209 @@
+#ifndef _ASM_POWERPC_ATOMIC_H_
+#define _ASM_POWERPC_ATOMIC_H_
+
+/*
+ * PowerPC atomic operations
+ */
+
+typedef struct { volatile int counter; } atomic_t;
+
+#ifdef __KERNEL__
+#include <asm/synch.h>
+
+#define ATOMIC_INIT(i)          { (i) }
+
+#define atomic_read(v)          ((v)->counter)
+#define atomic_set(v,i)         (((v)->counter) = (i))
+
+/* Erratum #77 on the 405 means we need a sync or dcbt before every stwcx.
+ * The old ATOMIC_SYNC_FIX covered some but not all of this.
+ */
+#ifdef CONFIG_IBM405_ERR77
+#define PPC405_ERR77(ra,rb)     "dcbt " #ra "," #rb ";"
+#else
+#define PPC405_ERR77(ra,rb)
+#endif
+
+static __inline__ void atomic_add(int a, atomic_t *v)
+{
+        int t;
+
+        __asm__ __volatile__(
+"1:     lwarx   %0,0,%3         # atomic_add\n\
+        add     %0,%2,%0\n"
+        PPC405_ERR77(0,%3)
+"       stwcx.  %0,0,%3 \n\
+        bne-    1b"
+        : "=&r" (t), "=m" (v->counter)
+        : "r" (a), "r" (&v->counter), "m" (v->counter)
+        : "cc");
+}
+
+static __inline__ int atomic_add_return(int a, atomic_t *v)
+{
+        int t;
+
+        __asm__ __volatile__(
+        EIEIO_ON_SMP
+"1:     lwarx   %0,0,%2         # atomic_add_return\n\
+        add     %0,%1,%0\n"
+        PPC405_ERR77(0,%2)
+"       stwcx.  %0,0,%2 \n\
+        bne-    1b"
+        ISYNC_ON_SMP
+        : "=&r" (t)
+        : "r" (a), "r" (&v->counter)
+        : "cc", "memory");
+
+        return t;
+}
+
+#define atomic_add_negative(a, v)       (atomic_add_return((a), (v)) < 0)
+
+static __inline__ void atomic_sub(int a, atomic_t *v)
+{
+        int t;
+
+        __asm__ __volatile__(
+"1:     lwarx   %0,0,%3         # atomic_sub\n\
+        subf    %0,%2,%0\n"
+        PPC405_ERR77(0,%3)
+"       stwcx.  %0,0,%3 \n\
+        bne-    1b"
+        : "=&r" (t), "=m" (v->counter)
+        : "r" (a), "r" (&v->counter), "m" (v->counter)
+        : "cc");
+}
+
+static __inline__ int atomic_sub_return(int a, atomic_t *v)
+{
+        int t;
+
+        __asm__ __volatile__(
+        EIEIO_ON_SMP
+"1:     lwarx   %0,0,%2         # atomic_sub_return\n\
+        subf    %0,%1,%0\n"
+        PPC405_ERR77(0,%2)
+"       stwcx.  %0,0,%2 \n\
+        bne-    1b"
+        ISYNC_ON_SMP
+        : "=&r" (t)
+        : "r" (a), "r" (&v->counter)
+        : "cc", "memory");
+
+        return t;
+}
+
+static __inline__ void atomic_inc(atomic_t *v)
+{
+        int t;
+
+        __asm__ __volatile__(
+"1:     lwarx   %0,0,%2         # atomic_inc\n\
+        addic   %0,%0,1\n"
+        PPC405_ERR77(0,%2)
+"       stwcx.  %0,0,%2 \n\
+        bne-    1b"
+        : "=&r" (t), "=m" (v->counter)
+        : "r" (&v->counter), "m" (v->counter)
+        : "cc");
+}
+
+static __inline__ int atomic_inc_return(atomic_t *v)
+{
+        int t;
+
+        __asm__ __volatile__(
+        EIEIO_ON_SMP
+"1:     lwarx   %0,0,%1         # atomic_inc_return\n\
+        addic   %0,%0,1\n"
+        PPC405_ERR77(0,%1)
+"       stwcx.  %0,0,%1 \n\
+        bne-    1b"
+        ISYNC_ON_SMP
+        : "=&r" (t)
+        : "r" (&v->counter)
+        : "cc", "memory");
+
+        return t;
+}
+
+/*
+ * atomic_inc_and_test - increment and test
+ * @v: pointer of type atomic_t
+ *
+ * Atomically increments @v by 1
+ * and returns true if the result is zero, or false for all
+ * other cases.
+ */
+#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
+
+static __inline__ void atomic_dec(atomic_t *v)
+{
+        int t;
+
+        __asm__ __volatile__(
+"1:     lwarx   %0,0,%2         # atomic_dec\n\
+        addic   %0,%0,-1\n"
+        PPC405_ERR77(0,%2)\
+"       stwcx.  %0,0,%2\n\
+        bne-    1b"
+        : "=&r" (t), "=m" (v->counter)
+        : "r" (&v->counter), "m" (v->counter)
+        : "cc");
+}
+
+static __inline__ int atomic_dec_return(atomic_t *v)
+{
+        int t;
+
+        __asm__ __volatile__(
+        EIEIO_ON_SMP
+"1:     lwarx   %0,0,%1         # atomic_dec_return\n\
+        addic   %0,%0,-1\n"
+        PPC405_ERR77(0,%1)
+"       stwcx.  %0,0,%1\n\
+        bne-    1b"
+        ISYNC_ON_SMP
+        : "=&r" (t)
+        : "r" (&v->counter)
+        : "cc", "memory");
+
+        return t;
+}
+
+#define atomic_sub_and_test(a, v)       (atomic_sub_return((a), (v)) == 0)
+#define atomic_dec_and_test(v)          (atomic_dec_return((v)) == 0)
+
+/*
+ * Atomically test *v and decrement if it is greater than 0.
+ * The function returns the old value of *v minus 1.
+ */
+static __inline__ int atomic_dec_if_positive(atomic_t *v)
+{
+        int t;
+
+        __asm__ __volatile__(
+        EIEIO_ON_SMP
+"1:     lwarx   %0,0,%1         # atomic_dec_if_positive\n\
+        addic.  %0,%0,-1\n\
+        blt-    2f\n"
+        PPC405_ERR77(0,%1)
+"       stwcx.  %0,0,%1\n\
+        bne-    1b"
+        ISYNC_ON_SMP
+        "\n\
+2:"     : "=&r" (t)
+        : "r" (&v->counter)
+        : "cc", "memory");
+
+        return t;
+}
+
+#define smp_mb__before_atomic_dec()     smp_mb()
+#define smp_mb__after_atomic_dec()      smp_mb()
+#define smp_mb__before_atomic_inc()     smp_mb()
+#define smp_mb__after_atomic_inc()      smp_mb()
+
+#endif /* __KERNEL__ */
+#endif /* _ASM_POWERPC_ATOMIC_H_ */