1 files changed, 199 insertions, 0 deletions
diff --git a/include/asm-parisc/atomic.h b/include/asm-parisc/atomic.h
new file mode 100644
index 000000000000..e24f7579adb0
--- /dev/null
+++ b/include/asm-parisc/atomic.h
@@ -0,0 +1,199 @@
+#ifndef _ASM_PARISC_ATOMIC_H_
+#define _ASM_PARISC_ATOMIC_H_
+
+#include <linux/config.h>
+#include <asm/system.h>
+/* Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>.  */
+
+/*
+ * Atomic operations that C can't guarantee us.  Useful for
+ * resource counting etc..
+ *
+ * And probably incredibly slow on parisc.  OTOH, we don't
+ * have to write any serious assembly.   prumpf
+ */
+
+#ifdef CONFIG_SMP
+#include <asm/spinlock.h>
+#include <asm/cache.h>		/* we use L1_CACHE_BYTES */
+
+/* Use an array of spinlocks for our atomic_ts.
+ * Hash function to index into a different SPINLOCK.
+ * Since "a" is usually an address, use one spinlock per cacheline.
+ */
+#  define ATOMIC_HASH_SIZE 4
+#  define ATOMIC_HASH(a) (&(__atomic_hash[ (((unsigned long) a)/L1_CACHE_BYTES) & (ATOMIC_HASH_SIZE-1) ]))
+
+extern spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] __lock_aligned;
+
+/* Can't use _raw_spin_lock_irq because of #include problems, so
+ * this is the substitute */
+#define _atomic_spin_lock_irqsave(l,f) do {	\
+	spinlock_t *s = ATOMIC_HASH(l);		\
+	local_irq_save(f);			\
+	_raw_spin_lock(s);			\
+} while(0)
+
+#define _atomic_spin_unlock_irqrestore(l,f) do {	\
+	spinlock_t *s = ATOMIC_HASH(l);			\
+	_raw_spin_unlock(s);				\
+	local_irq_restore(f);				\
+} while(0)
+
+
+#else
+#  define _atomic_spin_lock_irqsave(l,f) do { local_irq_save(f); } while (0)
+#  define _atomic_spin_unlock_irqrestore(l,f) do { local_irq_restore(f); } while (0)
+#endif
+
+/* Note that we need not lock read accesses - aligned word writes/reads
+ * are atomic, so a reader never sees unconsistent values.
+ *
+ * Cache-line alignment would conflict with, for example, linux/module.h
+ */
+
+typedef struct { volatile int counter; } atomic_t;
+
+
+/* This should get optimized out since it's never called.
+** Or get a link error if xchg is used "wrong".
+*/
+extern void __xchg_called_with_bad_pointer(void);
+
+
+/* __xchg32/64 defined in arch/parisc/lib/bitops.c */
+extern unsigned long __xchg8(char, char *);
+extern unsigned long __xchg32(int, int *);
+#ifdef __LP64__
+extern unsigned long __xchg64(unsigned long, unsigned long *);
+#endif
+
+/* optimizer better get rid of switch since size is a constant */
+static __inline__ unsigned long __xchg(unsigned long x, __volatile__ void * ptr,
+                                       int size)
+{
+
+	switch(size) {
+#ifdef __LP64__
+	case 8: return __xchg64(x,(unsigned long *) ptr);
+#endif
+	case 4: return __xchg32((int) x, (int *) ptr);
+	case 1: return __xchg8((char) x, (char *) ptr);
+	}
+	__xchg_called_with_bad_pointer();
+	return x;
+}
+
+
+/*
+** REVISIT - Abandoned use of LDCW in xchg() for now:
+** o need to test sizeof(*ptr) to avoid clearing adjacent bytes
+** o and while we are at it, could __LP64__ code use LDCD too?
+**
+**	if (__builtin_constant_p(x) && (x == NULL))
+**		if (((unsigned long)p & 0xf) == 0)
+**			return __ldcw(p);
+*/
+#define xchg(ptr,x) \
+	((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
+
+
+#define __HAVE_ARCH_CMPXCHG	1
+
+/* bug catcher for when unsupported size is used - won't link */
+extern void __cmpxchg_called_with_bad_pointer(void);
+
+/* __cmpxchg_u32/u64 defined in arch/parisc/lib/bitops.c */
+extern unsigned long __cmpxchg_u32(volatile unsigned int *m, unsigned int old, unsigned int new_);
+extern unsigned long __cmpxchg_u64(volatile unsigned long *ptr, unsigned long old, unsigned long 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) {
+#ifdef __LP64__
+	case 8: return __cmpxchg_u64((unsigned long *)ptr, old, new_);
+#endif
+	case 4: return __cmpxchg_u32((unsigned int *)ptr, (unsigned int) old, (unsigned int) new_);
+	}
+	__cmpxchg_called_with_bad_pointer();
+	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))); \
+  })
+
+
+
+/* It's possible to reduce all atomic operations to either
+ * __atomic_add_return, atomic_set and atomic_read (the latter
+ * is there only for consistency).
+ */
+
+static __inline__ int __atomic_add_return(int i, atomic_t *v)
+{
+	int ret;
+	unsigned long flags;
+	_atomic_spin_lock_irqsave(v, flags);
+
+	ret = (v->counter += i);
+
+	_atomic_spin_unlock_irqrestore(v, flags);
+	return ret;
+}
+
+static __inline__ void atomic_set(atomic_t *v, int i) 
+{
+	unsigned long flags;
+	_atomic_spin_lock_irqsave(v, flags);
+
+	v->counter = i;
+
+	_atomic_spin_unlock_irqrestore(v, flags);
+}
+
+static __inline__ int atomic_read(const atomic_t *v)
+{
+	return v->counter;
+}
+
+/* exported interface */
+
+#define atomic_add(i,v)	((void)(__atomic_add_return( ((int)i),(v))))
+#define atomic_sub(i,v)	((void)(__atomic_add_return(-((int)i),(v))))
+#define atomic_inc(v)	((void)(__atomic_add_return(   1,(v))))
+#define atomic_dec(v)	((void)(__atomic_add_return(  -1,(v))))
+
+#define atomic_add_return(i,v)	(__atomic_add_return( ((int)i),(v)))
+#define atomic_sub_return(i,v)	(__atomic_add_return(-((int)i),(v)))
+#define atomic_inc_return(v)	(__atomic_add_return(   1,(v)))
+#define atomic_dec_return(v)	(__atomic_add_return(  -1,(v)))
+
+#define atomic_add_negative(a, v)	(atomic_add_return((a), (v)) < 0)
+
+/*
+ * 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)
+
+#define atomic_dec_and_test(v)	(atomic_dec_return(v) == 0)
+
+#define ATOMIC_INIT(i)	{ (i) }
+
+#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