powerpc: implement atomic64_t on ppc64

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

include/asm-powerpc/atomic.h

@@ -197,5 +197,183 @@ static __inline__ int atomic_dec_if_positive(atomic_t *v)
 #define smp_mb__before_atomic_inc()     smp_mb()
 #define smp_mb__after_atomic_inc()      smp_mb()
 
+#ifdef __powerpc64__
+
+typedef struct { volatile long counter; } atomic64_t;
+
+#define ATOMIC64_INIT(i)	{ (i) }
+
+#define atomic64_read(v)	((v)->counter)
+#define atomic64_set(v,i)	(((v)->counter) = (i))
+
+static __inline__ void atomic64_add(long a, atomic64_t *v)
+{
+	long t;
+
+	__asm__ __volatile__(
+"1:	ldarx	%0,0,%3		# atomic64_add\n\
+	add	%0,%2,%0\n\
+	stdcx.	%0,0,%3 \n\
+	bne-	1b"
+	: "=&r" (t), "=m" (v->counter)
+	: "r" (a), "r" (&v->counter), "m" (v->counter)
+	: "cc");
+}
+
+static __inline__ long atomic64_add_return(long a, atomic64_t *v)
+{
+	long t;
+
+	__asm__ __volatile__(
+	EIEIO_ON_SMP
+"1:	ldarx	%0,0,%2		# atomic64_add_return\n\
+	add	%0,%1,%0\n\
+	stdcx.	%0,0,%2 \n\
+	bne-	1b"
+	ISYNC_ON_SMP
+	: "=&r" (t)
+	: "r" (a), "r" (&v->counter)
+	: "cc", "memory");
+
+	return t;
+}
+
+#define atomic64_add_negative(a, v)	(atomic64_add_return((a), (v)) < 0)
+
+static __inline__ void atomic64_sub(long a, atomic64_t *v)
+{
+	long t;
+
+	__asm__ __volatile__(
+"1:	ldarx	%0,0,%3		# atomic64_sub\n\
+	subf	%0,%2,%0\n\
+	stdcx.	%0,0,%3 \n\
+	bne-	1b"
+	: "=&r" (t), "=m" (v->counter)
+	: "r" (a), "r" (&v->counter), "m" (v->counter)
+	: "cc");
+}
+
+static __inline__ long atomic64_sub_return(long a, atomic64_t *v)
+{
+	long t;
+
+	__asm__ __volatile__(
+	EIEIO_ON_SMP
+"1:	ldarx	%0,0,%2		# atomic64_sub_return\n\
+	subf	%0,%1,%0\n\
+	stdcx.	%0,0,%2 \n\
+	bne-	1b"
+	ISYNC_ON_SMP
+	: "=&r" (t)
+	: "r" (a), "r" (&v->counter)
+	: "cc", "memory");
+
+	return t;
+}
+
+static __inline__ void atomic64_inc(atomic64_t *v)
+{
+	long t;
+
+	__asm__ __volatile__(
+"1:	ldarx	%0,0,%2		# atomic64_inc\n\
+	addic	%0,%0,1\n\
+	stdcx.	%0,0,%2 \n\
+	bne-	1b"
+	: "=&r" (t), "=m" (v->counter)
+	: "r" (&v->counter), "m" (v->counter)
+	: "cc");
+}
+
+static __inline__ long atomic64_inc_return(atomic64_t *v)
+{
+	long t;
+
+	__asm__ __volatile__(
+	EIEIO_ON_SMP
+"1:	ldarx	%0,0,%1		# atomic64_inc_return\n\
+	addic	%0,%0,1\n\
+	stdcx.	%0,0,%1 \n\
+	bne-	1b"
+	ISYNC_ON_SMP
+	: "=&r" (t)
+	: "r" (&v->counter)
+	: "cc", "memory");
+
+	return t;
+}
+
+/*
+ * atomic64_inc_and_test - increment and test
+ * @v: pointer of type atomic64_t
+ *
+ * Atomically increments @v by 1
+ * and returns true if the result is zero, or false for all
+ * other cases.
+ */
+#define atomic64_inc_and_test(v) (atomic64_inc_return(v) == 0)
+
+static __inline__ void atomic64_dec(atomic64_t *v)
+{
+	long t;
+
+	__asm__ __volatile__(
+"1:	ldarx	%0,0,%2		# atomic64_dec\n\
+	addic	%0,%0,-1\n\
+	stdcx.	%0,0,%2\n\
+	bne-	1b"
+	: "=&r" (t), "=m" (v->counter)
+	: "r" (&v->counter), "m" (v->counter)
+	: "cc");
+}
+
+static __inline__ long atomic64_dec_return(atomic64_t *v)
+{
+	long t;
+
+	__asm__ __volatile__(
+	EIEIO_ON_SMP
+"1:	ldarx	%0,0,%1		# atomic64_dec_return\n\
+	addic	%0,%0,-1\n\
+	stdcx.	%0,0,%1\n\
+	bne-	1b"
+	ISYNC_ON_SMP
+	: "=&r" (t)
+	: "r" (&v->counter)
+	: "cc", "memory");
+
+	return t;
+}
+
+#define atomic64_sub_and_test(a, v)	(atomic64_sub_return((a), (v)) == 0)
+#define atomic64_dec_and_test(v)	(atomic64_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__ long atomic64_dec_if_positive(atomic64_t *v)
+{
+	long t;
+
+	__asm__ __volatile__(
+	EIEIO_ON_SMP
+"1:	ldarx	%0,0,%1		# atomic64_dec_if_positive\n\
+	addic.	%0,%0,-1\n\
+	blt-	2f\n\
+	stdcx.	%0,0,%1\n\
+	bne-	1b"
+	ISYNC_ON_SMP
+	"\n\
+2:"	: "=&r" (t)
+	: "r" (&v->counter)
+	: "cc", "memory");
+
+	return t;
+}
+
+#endif /* __powerpc64__ */
+
 #endif /* __KERNEL__ */
 #endif /* _ASM_POWERPC_ATOMIC_H_ */