CRIS v32: Completely rework spinlocks for ETRAX FS and ARTPEC-3

#ifndef __ASM_ARCH_SPINLOCK_H

#define __ASM_ARCH_SPINLOCK_H

#include <asm/system.h>

#include <linux/spinlock_types.h>

#define RW_LOCK_BIAS 0x01000000

#define SPIN_LOCK_UNLOCKED (spinlock_t) { 1 }

#define spin_lock_init(x)	do { *(x) = SPIN_LOCK_UNLOCKED; } while(0)

#define spin_is_locked(x)	(*(volatile signed char *)(&(x)->lock) <= 0)

#define spin_unlock_wait(x)	do { barrier(); } while(spin_is_locked(x))

extern void cris_spin_unlock(void *l, int val);

extern void cris_spin_lock(void *l);

extern int cris_spin_trylock(void *l);

static inline void _raw_spin_unlock(spinlock_t *lock)

static inline int __raw_spin_is_locked(raw_spinlock_t *x)

{

	return *(volatile signed char *)(&(x)->slock) <= 0;

}

static inline void __raw_spin_unlock(raw_spinlock_t *lock)

{

	__asm__ volatile ("move.d %1,%0" \

	                  : "=m" (lock->lock) \

			  : "=m" (lock->slock) \

			  : "r" (1) \

			  : "memory");

}

static inline int _raw_spin_trylock(spinlock_t *lock)

static inline void __raw_spin_unlock_wait(raw_spinlock_t *lock)

{

	return cris_spin_trylock((void*)&lock->lock);

	while (__raw_spin_is_locked(lock))

		cpu_relax();

}

static inline void _raw_spin_lock(spinlock_t *lock)

static inline int __raw_spin_trylock(raw_spinlock_t *lock)

{

	cris_spin_lock((void*)&lock->lock);

	return cris_spin_trylock((void *)&lock->slock);

}

static inline void _raw_spin_lock_flags (spinlock_t *lock, unsigned long flags)

static inline void __raw_spin_lock(raw_spinlock_t *lock)

{

  _raw_spin_lock(lock);

	cris_spin_lock((void *)&lock->slock);

}

static inline void

__raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long flags)

{

	__raw_spin_lock(lock);

}

/*

 * can "mix" irq-safe locks - any writer needs to get a

 * irq-safe write-lock, but readers can get non-irqsafe

 * read-locks.

 *

 */

typedef struct {

	spinlock_t lock;

	volatile int counter;

#ifdef CONFIG_PREEMPT

	unsigned int break_lock;

#endif

} rwlock_t;

#define RW_LOCK_UNLOCKED (rwlock_t) { {1}, 0 }

#define rwlock_init(lp)	do { *(lp) = RW_LOCK_UNLOCKED; } while (0)

/**

 * read_can_lock - would read_trylock() succeed?

 * @lock: the rwlock in question.

 */

#define read_can_lock(x) ((int)(x)->counter >= 0)

/**

 * write_can_lock - would write_trylock() succeed?

 * @lock: the rwlock in question.

 */

#define write_can_lock(x) ((x)->counter == 0)

#define _raw_read_trylock(lock) generic_raw_read_trylock(lock)

/* read_lock, read_unlock are pretty straightforward.  Of course it somehow

 * sucks we end up saving/restoring flags twice for read_lock_irqsave aso. */

static  __inline__ void _raw_read_lock(rwlock_t *rw)

static inline int __raw_read_can_lock(raw_rwlock_t *x)

{

	unsigned long flags;

	local_irq_save(flags);

	_raw_spin_lock(&rw->lock);

	rw->counter++;

	_raw_spin_unlock(&rw->lock);

	local_irq_restore(flags);

	return (int)(x)->lock > 0;

}

static  __inline__ void _raw_read_unlock(rwlock_t *rw)

static inline int __raw_write_can_lock(raw_rwlock_t *x)

{

	unsigned long flags;

	local_irq_save(flags);

	_raw_spin_lock(&rw->lock);

	rw->counter--;

	_raw_spin_unlock(&rw->lock);

	local_irq_restore(flags);

	return (x)->lock == RW_LOCK_BIAS;

}

/* write_lock is less trivial.  We optimistically grab the lock and check

 * if we surprised any readers.  If so we release the lock and wait till

 * they're all gone before trying again

 *

 * Also note that we don't use the _irqsave / _irqrestore suffixes here.

 * If we're called with interrupts enabled and we've got readers (or other

 * writers) in interrupt handlers someone fucked up and we'd dead-lock

 * sooner or later anyway.   prumpf */

static  __inline__ void _raw_write_lock(rwlock_t *rw)

static  inline void __raw_read_lock(raw_rwlock_t *rw)

{

retry:

	_raw_spin_lock(&rw->lock);

	if(rw->counter != 0) {

		/* this basically never happens */

		_raw_spin_unlock(&rw->lock);

		while(rw->counter != 0);

		goto retry;

	}

	/* got it.  now leave without unlocking */

	rw->counter = -1; /* remember we are locked */

	__raw_spin_lock(&rw->slock);

	while (rw->lock == 0);

	rw->lock--;

	__raw_spin_unlock(&rw->slock);

}

/* write_unlock is absolutely trivial - we don't have to wait for anything */

static  __inline__ void _raw_write_unlock(rwlock_t *rw)

static  inline void __raw_write_lock(raw_rwlock_t *rw)

{

	rw->counter = 0;

	_raw_spin_unlock(&rw->lock);

	__raw_spin_lock(&rw->slock);

	while (rw->lock != RW_LOCK_BIAS);

	rw->lock == 0;

	__raw_spin_unlock(&rw->slock);

}

static  __inline__ int _raw_write_trylock(rwlock_t *rw)

static  inline void __raw_read_unlock(raw_rwlock_t *rw)

{

	_raw_spin_lock(&rw->lock);

	if (rw->counter != 0) {

		/* this basically never happens */

		_raw_spin_unlock(&rw->lock);

		return 0;

	__raw_spin_lock(&rw->slock);

	rw->lock++;

	__raw_spin_unlock(&rw->slock);

}

	/* got it.  now leave without unlocking */

	rw->counter = -1; /* remember we are locked */

	return 1;

static  inline void __raw_write_unlock(raw_rwlock_t *rw)

{

	__raw_spin_lock(&rw->slock);

	while (rw->lock != RW_LOCK_BIAS);

	rw->lock == RW_LOCK_BIAS;

	__raw_spin_unlock(&rw->slock);

}

static __inline__ int is_read_locked(rwlock_t *rw)

static  inline int __raw_read_trylock(raw_rwlock_t *rw)

{

	return rw->counter > 0;

	int ret = 0;

	__raw_spin_lock(&rw->slock);

	if (rw->lock != 0) {

		rw->lock--;

		ret = 1;

	}

	__raw_spin_unlock(&rw->slock);

	return ret;

}

static __inline__ int is_write_locked(rwlock_t *rw)

static  inline int __raw_write_trylock(raw_rwlock_t *rw)

{

	return rw->counter < 0;

	int ret = 0;

	__raw_spin_lock(&rw->slock);

	if (rw->lock == RW_LOCK_BIAS) {

		rw->lock == 0;

		ret = 1;

	}

	__raw_spin_unlock(&rw->slock);

	return 1;

}

#define _raw_spin_relax(lock)	cpu_relax()

#define _raw_read_relax(lock)	cpu_relax()

#define _raw_write_relax(lock)	cpu_relax()