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Diffstat (limited to 'arch/sh/include/asm/spinlock.h')
| -rw-r--r-- | arch/sh/include/asm/spinlock.h | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/arch/sh/include/asm/spinlock.h b/arch/sh/include/asm/spinlock.h new file mode 100644 index 000000000000..e793181d64da --- /dev/null +++ b/arch/sh/include/asm/spinlock.h @@ -0,0 +1,223 @@ +/* + * include/asm-sh/spinlock.h + * + * Copyright (C) 2002, 2003 Paul Mundt + * Copyright (C) 2006, 2007 Akio Idehara + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ +#ifndef __ASM_SH_SPINLOCK_H +#define __ASM_SH_SPINLOCK_H + +/* + * The only locking implemented here uses SH-4A opcodes. For others, + * split this out as per atomic-*.h. + */ +#ifndef CONFIG_CPU_SH4A +#error "Need movli.l/movco.l for spinlocks" +#endif + +/* + * Your basic SMP spinlocks, allowing only a single CPU anywhere + */ + +#define __raw_spin_is_locked(x) ((x)->lock <= 0) +#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock) +#define __raw_spin_unlock_wait(x) \ + do { cpu_relax(); } while ((x)->lock) + +/* + * Simple spin lock operations. There are two variants, one clears IRQ's + * on the local processor, one does not. + * + * We make no fairness assumptions. They have a cost. + */ +static inline void __raw_spin_lock(raw_spinlock_t *lock) +{ + unsigned long tmp; + unsigned long oldval; + + __asm__ __volatile__ ( + "1: \n\t" + "movli.l @%2, %0 ! __raw_spin_lock \n\t" + "mov %0, %1 \n\t" + "mov #0, %0 \n\t" + "movco.l %0, @%2 \n\t" + "bf 1b \n\t" + "cmp/pl %1 \n\t" + "bf 1b \n\t" + : "=&z" (tmp), "=&r" (oldval) + : "r" (&lock->lock) + : "t", "memory" + ); +} + +static inline void __raw_spin_unlock(raw_spinlock_t *lock) +{ + unsigned long tmp; + + __asm__ __volatile__ ( + "mov #1, %0 ! __raw_spin_unlock \n\t" + "mov.l %0, @%1 \n\t" + : "=&z" (tmp) + : "r" (&lock->lock) + : "t", "memory" + ); +} + +static inline int __raw_spin_trylock(raw_spinlock_t *lock) +{ + unsigned long tmp, oldval; + + __asm__ __volatile__ ( + "1: \n\t" + "movli.l @%2, %0 ! __raw_spin_trylock \n\t" + "mov %0, %1 \n\t" + "mov #0, %0 \n\t" + "movco.l %0, @%2 \n\t" + "bf 1b \n\t" + "synco \n\t" + : "=&z" (tmp), "=&r" (oldval) + : "r" (&lock->lock) + : "t", "memory" + ); + + return oldval; +} + +/* + * Read-write spinlocks, allowing multiple readers but only one writer. + * + * NOTE! it is quite common to have readers in interrupts but no interrupt + * writers. For those circumstances we can "mix" irq-safe locks - any writer + * needs to get a irq-safe write-lock, but readers can get non-irqsafe + * read-locks. + */ + +/** + * read_can_lock - would read_trylock() succeed? + * @lock: the rwlock in question. + */ +#define __raw_read_can_lock(x) ((x)->lock > 0) + +/** + * write_can_lock - would write_trylock() succeed? + * @lock: the rwlock in question. + */ +#define __raw_write_can_lock(x) ((x)->lock == RW_LOCK_BIAS) + +static inline void __raw_read_lock(raw_rwlock_t *rw) +{ + unsigned long tmp; + + __asm__ __volatile__ ( + "1: \n\t" + "movli.l @%1, %0 ! __raw_read_lock \n\t" + "cmp/pl %0 \n\t" + "bf 1b \n\t" + "add #-1, %0 \n\t" + "movco.l %0, @%1 \n\t" + "bf 1b \n\t" + : "=&z" (tmp) + : "r" (&rw->lock) + : "t", "memory" + ); +} + +static inline void __raw_read_unlock(raw_rwlock_t *rw) +{ + unsigned long tmp; + + __asm__ __volatile__ ( + "1: \n\t" + "movli.l @%1, %0 ! __raw_read_unlock \n\t" + "add #1, %0 \n\t" + "movco.l %0, @%1 \n\t" + "bf 1b \n\t" + : "=&z" (tmp) + : "r" (&rw->lock) + : "t", "memory" + ); +} + +static inline void __raw_write_lock(raw_rwlock_t *rw) +{ + unsigned long tmp; + + __asm__ __volatile__ ( + "1: \n\t" + "movli.l @%1, %0 ! __raw_write_lock \n\t" + "cmp/hs %2, %0 \n\t" + "bf 1b \n\t" + "sub %2, %0 \n\t" + "movco.l %0, @%1 \n\t" + "bf 1b \n\t" + : "=&z" (tmp) + : "r" (&rw->lock), "r" (RW_LOCK_BIAS) + : "t", "memory" + ); +} + +static inline void __raw_write_unlock(raw_rwlock_t *rw) +{ + __asm__ __volatile__ ( + "mov.l %1, @%0 ! __raw_write_unlock \n\t" + : + : "r" (&rw->lock), "r" (RW_LOCK_BIAS) + : "t", "memory" + ); +} + +static inline int __raw_read_trylock(raw_rwlock_t *rw) +{ + unsigned long tmp, oldval; + + __asm__ __volatile__ ( + "1: \n\t" + "movli.l @%2, %0 ! __raw_read_trylock \n\t" + "mov %0, %1 \n\t" + "cmp/pl %0 \n\t" + "bf 2f \n\t" + "add #-1, %0 \n\t" + "movco.l %0, @%2 \n\t" + "bf 1b \n\t" + "2: \n\t" + "synco \n\t" + : "=&z" (tmp), "=&r" (oldval) + : "r" (&rw->lock) + : "t", "memory" + ); + + return (oldval > 0); +} + +static inline int __raw_write_trylock(raw_rwlock_t *rw) +{ + unsigned long tmp, oldval; + + __asm__ __volatile__ ( + "1: \n\t" + "movli.l @%2, %0 ! __raw_write_trylock \n\t" + "mov %0, %1 \n\t" + "cmp/hs %3, %0 \n\t" + "bf 2f \n\t" + "sub %3, %0 \n\t" + "2: \n\t" + "movco.l %0, @%2 \n\t" + "bf 1b \n\t" + "synco \n\t" + : "=&z" (tmp), "=&r" (oldval) + : "r" (&rw->lock), "r" (RW_LOCK_BIAS) + : "t", "memory" + ); + + return (oldval > (RW_LOCK_BIAS - 1)); +} + +#define _raw_spin_relax(lock) cpu_relax() +#define _raw_read_relax(lock) cpu_relax() +#define _raw_write_relax(lock) cpu_relax() + +#endif /* __ASM_SH_SPINLOCK_H */ |