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

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This commit is contained in:
Jesper Nilsson 2008-01-28 18:07:58 +01:00
parent 4258fb1932
commit de1c1419f9
1 changed files with 75 additions and 113 deletions
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188
include/asm-cris/arch-v32/spinlock.h
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@ -1,40 +1,47 @@
#ifndef __ASM_ARCH_SPINLOCK_H #ifndef __ASM_ARCH_SPINLOCK_H
#define __ASM_ARCH_SPINLOCK_H #define __ASM_ARCH_SPINLOCK_H
#include <asm/system.h> #include <linux/spinlock_types.h>
#define RW_LOCK_BIAS 0x01000000 #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_unlock(void *l, int val);
extern void cris_spin_lock(void *l); extern void cris_spin_lock(void *l);
extern int cris_spin_trylock(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" \ __asm__ volatile ("move.d %1,%0" \
: "=m" (lock->lock) \ : "=m" (lock->slock) \
: "r" (1) \ : "r" (1) \
: "memory"); : "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);
} }
/* /*
@ -46,119 +53,74 @@ static inline void _raw_spin_lock_flags (spinlock_t *lock, unsigned long flags)
* can "mix" irq-safe locks - any writer needs to get a * can "mix" irq-safe locks - any writer needs to get a
* irq-safe write-lock, but readers can get non-irqsafe * irq-safe write-lock, but readers can get non-irqsafe
* read-locks. * 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)
{
unsigned long flags;
local_irq_save(flags);
_raw_spin_lock(&rw->lock);
rw->counter++;
_raw_spin_unlock(&rw->lock);
local_irq_restore(flags);
}
static __inline__ void _raw_read_unlock(rwlock_t *rw)
{
unsigned long flags;
local_irq_save(flags);
_raw_spin_lock(&rw->lock);
rw->counter--;
_raw_spin_unlock(&rw->lock);
local_irq_restore(flags);
}
/* 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 int __raw_read_can_lock(raw_rwlock_t *x)
{ {
retry: return (int)(x)->lock > 0;
_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 */
} }
/* write_unlock is absolutely trivial - we don't have to wait for anything */ static inline int __raw_write_can_lock(raw_rwlock_t *x)
static __inline__ void _raw_write_unlock(rwlock_t *rw)
{ {
rw->counter = 0; return (x)->lock == RW_LOCK_BIAS;
_raw_spin_unlock(&rw->lock);
} }
static __inline__ int _raw_write_trylock(rwlock_t *rw) static inline void __raw_read_lock(raw_rwlock_t *rw)
{ {
_raw_spin_lock(&rw->lock); __raw_spin_lock(&rw->slock);
if (rw->counter != 0) { while (rw->lock == 0);
/* this basically never happens */ rw->lock--;
_raw_spin_unlock(&rw->lock); __raw_spin_unlock(&rw->slock);
}
return 0; static inline void __raw_write_lock(raw_rwlock_t *rw)
{
__raw_spin_lock(&rw->slock);
while (rw->lock != RW_LOCK_BIAS);
rw->lock == 0;
__raw_spin_unlock(&rw->slock);
}
static inline void __raw_read_unlock(raw_rwlock_t *rw)
{
__raw_spin_lock(&rw->slock);
rw->lock++;
__raw_spin_unlock(&rw->slock);
}
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 __raw_read_trylock(raw_rwlock_t *rw)
{
int ret = 0;
__raw_spin_lock(&rw->slock);
if (rw->lock != 0) {
rw->lock--;
ret = 1;
} }
__raw_spin_unlock(&rw->slock);
return ret;
}
/* got it. now leave without unlocking */ static inline int __raw_write_trylock(raw_rwlock_t *rw)
rw->counter = -1; /* remember we are locked */ {
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; return 1;
} }
static __inline__ int is_read_locked(rwlock_t *rw)
{
return rw->counter > 0;
}
static __inline__ int is_write_locked(rwlock_t *rw)
{
return rw->counter < 0;
}
#define _raw_spin_relax(lock) cpu_relax() #define _raw_spin_relax(lock) cpu_relax()
#define _raw_read_relax(lock) cpu_relax() #define _raw_read_relax(lock) cpu_relax()