U-Boot

/* 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 int atomic_inc_return(atomic_t *v)
{
	unsigned long flags = 0;
	int val;

	local_irq_save(flags);
	val = ++v->counter;
	local_irq_restore(flags);

	return val;
}

static inline int atomic_add_return(int i, atomic_t *v)
{
	unsigned long flags = 0;
	int val;

	local_irq_save(flags);
	val = (v->counter += i);
	local_irq_restore(flags);

	return val;
}

static inline int atomic_dec_if_positive(atomic_t *v)
{
	unsigned long flags = 0;
	int val;

	local_irq_save(flags);
	val = v->counter - 1;
	if (val >= 0)
		v->counter = val;
	local_irq_restore(flags);

	return val;
}

static inline int atomic_add_unless(atomic_t *v, int a, int u)
{
	unsigned long flags = 0;
	int ret = 1;

	local_irq_save(flags);
	if (v->counter != u)
		v->counter += a;
	else
		ret = 0;
	local_irq_restore(flags);

	return ret;
}

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);
}

/**
 * cmpxchg - compare and exchange
 * @ptr: pointer to the value
 * @old: expected old value
 * @new: new value to store if current equals old
 *
 * Single-threaded version for U-Boot. Atomically compares *ptr with old
 * and if equal, stores new. Returns the original value of *ptr.
 */
#ifndef cmpxchg
#define cmpxchg(ptr, old, new) ({		\
	typeof(*(ptr)) __cmpxchg_old = (old);	\
	typeof(*(ptr)) __cmpxchg_new = (new);	\
	typeof(*(ptr)) __cmpxchg_ret = *(ptr);	\
	if (__cmpxchg_ret == __cmpxchg_old)	\
		*(ptr) = __cmpxchg_new;		\
	__cmpxchg_ret;				\
})
#endif

/**
 * try_cmpxchg - compare and exchange with boolean return
 * @ptr: pointer to the value
 * @oldp: pointer to expected old value (updated on failure)
 * @new: new value to store if current equals old
 *
 * Returns true if exchange succeeded, false otherwise.
 * On failure, *oldp is updated with the current value.
 */
#ifndef try_cmpxchg
#define try_cmpxchg(ptr, oldp, new) ({		\
	typeof(*(oldp)) __old = *(oldp);	\
	typeof(*(ptr)) __ret = cmpxchg(ptr, __old, (new)); \
	if (__ret != __old)			\
		*(oldp) = __ret;		\
	__ret == __old;				\
})
#endif

/**
 * xchg - exchange value atomically
 * @ptr: pointer to the value
 * @new: new value to store
 *
 * Atomically stores new value and returns the old value.
 * Single-threaded version for U-Boot.
 */
#ifndef xchg
#define xchg(ptr, new) ({			\
	typeof(*(ptr)) __xchg_old = *(ptr);	\
	*(ptr) = (new);				\
	__xchg_old;				\
})
#endif

#endif