Add include/asm-generic/atomic.h

The arm, xtensa and mips version of atomic.h were already very similar
(the mips one was a copy of xtensa). Combine these implementations
together to produce a generic atomic.h that can be included by these
architectures (and any others that need it in future).

Signed-off-by: Chris Packham <judge.packham@gmail.com>
Reviewed-by: Tom Rini <trini@konsulko.com>

diff --git a/include/asm-generic/atomic.h b/include/asm-generic/atomic.h
new file mode 100644 (file)
index 0000000..94d0747
--- /dev/null
+++ b/include/asm-generic/atomic.h
@@ -0,0 +1,150 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+
+#ifndef _ASM_GENERIC_ATOMIC_H
+#define _ASM_GENERIC_ATOMIC_H
+
+typedef struct { volatile int counter; } atomic_t;
+#if BITS_PER_LONG == 32
+typedef struct { volatile long long counter; } atomic64_t;
+#else /* BIT_PER_LONG == 32 */
+typedef struct { volatile long counter; } atomic64_t;
+#endif
+
+#define ATOMIC_INIT(i) { (i) }
+
+#define atomic_read(v)         ((v)->counter)
+#define atomic_set(v, i)       ((v)->counter = (i))
+#define atomic64_read(v)       atomic_read(v)
+#define atomic64_set(v, i)     atomic_set(v, i)
+
+static inline void atomic_add(int i, atomic_t *v)
+{
+       unsigned long flags = 0;
+
+       local_irq_save(flags);
+       v->counter += i;
+       local_irq_restore(flags);
+}
+
+static inline void atomic_sub(int i, atomic_t *v)
+{
+       unsigned long flags = 0;
+
+       local_irq_save(flags);
+       v->counter -= i;
+       local_irq_restore(flags);
+}
+
+static inline void atomic_inc(atomic_t *v)
+{
+       unsigned long flags = 0;
+
+       local_irq_save(flags);
+       ++v->counter;
+       local_irq_restore(flags);
+}
+
+static inline void atomic_dec(atomic_t *v)
+{
+       unsigned long flags = 0;
+
+       local_irq_save(flags);
+       --v->counter;
+       local_irq_restore(flags);
+}
+
+static inline int atomic_dec_and_test(volatile atomic_t *v)
+{
+       unsigned long flags = 0;
+       int val;
+
+       local_irq_save(flags);
+       val = v->counter;
+       v->counter = val -= 1;
+       local_irq_restore(flags);
+
+       return val == 0;
+}
+
+static inline int atomic_add_negative(int i, volatile atomic_t *v)
+{
+       unsigned long flags = 0;
+       int val;
+
+       local_irq_save(flags);
+       val = v->counter;
+       v->counter = val += i;
+       local_irq_restore(flags);
+
+       return val < 0;
+}
+
+static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
+{
+       unsigned long flags = 0;
+
+       local_irq_save(flags);
+       *addr &= ~mask;
+       local_irq_restore(flags);
+}
+
+#if BITS_PER_LONG == 32
+
+static inline void atomic64_add(long long i, volatile atomic64_t *v)
+{
+       unsigned long flags = 0;
+
+       local_irq_save(flags);
+       v->counter += i;
+       local_irq_restore(flags);
+}
+
+static inline void atomic64_sub(long long i, volatile atomic64_t *v)
+{
+       unsigned long flags = 0;
+
+       local_irq_save(flags);
+       v->counter -= i;
+       local_irq_restore(flags);
+}
+
+#else /* BIT_PER_LONG == 32 */
+
+static inline void atomic64_add(long i, volatile atomic64_t *v)
+{
+       unsigned long flags = 0;
+
+       local_irq_save(flags);
+       v->counter += i;
+       local_irq_restore(flags);
+}
+
+static inline void atomic64_sub(long i, volatile atomic64_t *v)
+{
+       unsigned long flags = 0;
+
+       local_irq_save(flags);
+       v->counter -= i;
+       local_irq_restore(flags);
+}
+#endif
+
+static inline void atomic64_inc(volatile atomic64_t *v)
+{
+       unsigned long flags = 0;
+
+       local_irq_save(flags);
+       v->counter += 1;
+       local_irq_restore(flags);
+}
+
+static inline void atomic64_dec(volatile atomic64_t *v)
+{
+       unsigned long flags = 0;
+
+       local_irq_save(flags);
+       v->counter -= 1;
+       local_irq_restore(flags);
+}
+
+#endif