patch-2.4.0-test12 linux/include/asm-parisc/atomic.h

• Lines: 104
• Date: Wed Dec 6 11:46:39 2000
• Orig file: v2.4.0-test11/linux/include/asm-parisc/atomic.h
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.0-test11/linux/include/asm-parisc/atomic.h linux/include/asm-parisc/atomic.h
@@ -0,0 +1,103 @@
+#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
+/* we have an array of spinlocks for our atomic_ts, and a hash function
+ * to get the right index */
+#  define ATOMIC_HASH_SIZE 1
+#  define ATOMIC_HASH(a) (&__atomic_hash[0])
+
+extern spinlock_t __atomic_hash[ATOMIC_HASH_SIZE];
+/* copied from <asm/spinlock.h> and modified */
+#  define SPIN_LOCK(x) \
+	do { while(__ldcw(&(x)->lock) == 0); } while(0)
+	
+#  define SPIN_UNLOCK(x) \
+	do { (x)->lock = 1; } while(0)
+#else
+#  define ATOMIC_HASH_SIZE 1
+#  define ATOMIC_HASH(a)	(0)
+
+/* copied from <linux/spinlock.h> and modified */
+#  define SPIN_LOCK(x) (void)(x)
+	
+#  define SPIN_UNLOCK(x) do { } while(0)
+#endif
+
+/* copied from <linux/spinlock.h> and modified */
+#define SPIN_LOCK_IRQSAVE(lock, flags)		do { local_irq_save(flags);       SPIN_LOCK(lock); } while (0)
+#define SPIN_UNLOCK_IRQRESTORE(lock, flags)	do { SPIN_UNLOCK(lock);  local_irq_restore(flags); } while (0)
+
+/* 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;
+
+/* It's possible to reduce all atomic operations to either
+ * __atomic_add_return, __atomic_set and __atomic_ret (the latter
+ * is there only for consistency). */
+
+static __inline__ int __atomic_add_return(int i, atomic_t *v)
+{
+	int ret;
+	unsigned long flags;
+	SPIN_LOCK_IRQSAVE(ATOMIC_HASH(v), flags);
+
+	ret = (v->counter += i);
+
+	SPIN_UNLOCK_IRQRESTORE(ATOMIC_HASH(v), flags);
+	return ret;
+}
+
+static __inline__ void __atomic_set(atomic_t *v, int i) 
+{
+	unsigned long flags;
+	SPIN_LOCK_IRQSAVE(ATOMIC_HASH(v), flags);
+
+	v->counter = i;
+
+	SPIN_UNLOCK_IRQRESTORE(ATOMIC_HASH(v), flags);
+}
+	
+static __inline__ int __atomic_read(atomic_t *v)
+{
+	return v->counter;
+}
+
+/* exported interface */
+
+#define atomic_add(i,v)		((void)(__atomic_add_return( (i),(v))))
+#define atomic_sub(i,v)		((void)(__atomic_add_return(-(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( (i),(v)))
+#define atomic_sub_return(i,v)	(__atomic_add_return(-(i),(v)))
+#define atomic_inc_return(v)	(__atomic_add_return(   1,(v)))
+#define atomic_dec_return(v)	(__atomic_add_return(  -1,(v)))
+
+#define atomic_dec_and_test(v)	(atomic_dec_return(v) == 0)
+
+#define atomic_set(v,i)		(__atomic_set((v),i))
+#define atomic_read(v)		(__atomic_read(v))
+
+#define ATOMIC_INIT(i)	{ (i) }
+
+#endif