From de1c1419f9eb8f9d719aaaa3e3f3073069ecd657 Mon Sep 17 00:00:00 2001 From: Jesper Nilsson Date: Mon, 28 Jan 2008 18:07:58 +0100 Subject: CRIS v32: Completely rework spinlocks for ETRAX FS and ARTPEC-3 --- include/asm-cris/arch-v32/spinlock.h | 172 ++++++++++++++--------------------- 1 file changed, 67 insertions(+), 105 deletions(-) diff --git a/include/asm-cris/arch-v32/spinlock.h b/include/asm-cris/arch-v32/spinlock.h index 5f43df0a5fb4..0d5709b983a1 100644 --- a/include/asm-cris/arch-v32/spinlock.h +++ b/include/asm-cris/arch-v32/spinlock.h @@ -1,40 +1,47 @@ #ifndef __ASM_ARCH_SPINLOCK_H #define __ASM_ARCH_SPINLOCK_H -#include +#include #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); +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) +{ + while (__raw_spin_is_locked(lock)) + cpu_relax(); +} + +static inline int __raw_spin_trylock(raw_spinlock_t *lock) { - return cris_spin_trylock((void*)&lock->lock); + return cris_spin_trylock((void *)&lock->slock); } -static inline void _raw_spin_lock(spinlock_t *lock) +static inline void __raw_spin_lock(raw_spinlock_t *lock) { - cris_spin_lock((void*)&lock->lock); + cris_spin_lock((void *)&lock->slock); } -static inline void _raw_spin_lock_flags (spinlock_t *lock, unsigned long flags) +static inline void +__raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long flags) { - _raw_spin_lock(lock); + __raw_spin_lock(lock); } /* @@ -46,120 +53,75 @@ static inline void _raw_spin_lock_flags (spinlock_t *lock, unsigned long flags) * 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() -- cgit v1.2.3