diff options
Diffstat (limited to 'arch/sh/include/asm/spinlock-llsc.h')
| -rw-r--r-- | arch/sh/include/asm/spinlock-llsc.h | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/arch/sh/include/asm/spinlock-llsc.h b/arch/sh/include/asm/spinlock-llsc.h new file mode 100644 index 000000000..7fd929cd2 --- /dev/null +++ b/arch/sh/include/asm/spinlock-llsc.h @@ -0,0 +1,198 @@ +/* SPDX-License-Identifier: GPL-2.0 + * + * include/asm-sh/spinlock-llsc.h + * + * Copyright (C) 2002, 2003 Paul Mundt + * Copyright (C) 2006, 2007 Akio Idehara + */ +#ifndef __ASM_SH_SPINLOCK_LLSC_H +#define __ASM_SH_SPINLOCK_LLSC_H + +#include <asm/barrier.h> +#include <asm/processor.h> + +/* + * Your basic SMP spinlocks, allowing only a single CPU anywhere + */ + +#define arch_spin_is_locked(x) ((x)->lock <= 0) + +/* + * 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 arch_spin_lock(arch_spinlock_t *lock) +{ + unsigned long tmp; + unsigned long oldval; + + __asm__ __volatile__ ( + "1: \n\t" + "movli.l @%2, %0 ! arch_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 arch_spin_unlock(arch_spinlock_t *lock) +{ + unsigned long tmp; + + /* This could be optimised with ARCH_HAS_MMIOWB */ + mmiowb(); + __asm__ __volatile__ ( + "mov #1, %0 ! arch_spin_unlock \n\t" + "mov.l %0, @%1 \n\t" + : "=&z" (tmp) + : "r" (&lock->lock) + : "t", "memory" + ); +} + +static inline int arch_spin_trylock(arch_spinlock_t *lock) +{ + unsigned long tmp, oldval; + + __asm__ __volatile__ ( + "1: \n\t" + "movli.l @%2, %0 ! arch_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. + */ + +static inline void arch_read_lock(arch_rwlock_t *rw) +{ + unsigned long tmp; + + __asm__ __volatile__ ( + "1: \n\t" + "movli.l @%1, %0 ! arch_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 arch_read_unlock(arch_rwlock_t *rw) +{ + unsigned long tmp; + + __asm__ __volatile__ ( + "1: \n\t" + "movli.l @%1, %0 ! arch_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 arch_write_lock(arch_rwlock_t *rw) +{ + unsigned long tmp; + + __asm__ __volatile__ ( + "1: \n\t" + "movli.l @%1, %0 ! arch_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 arch_write_unlock(arch_rwlock_t *rw) +{ + __asm__ __volatile__ ( + "mov.l %1, @%0 ! arch_write_unlock \n\t" + : + : "r" (&rw->lock), "r" (RW_LOCK_BIAS) + : "t", "memory" + ); +} + +static inline int arch_read_trylock(arch_rwlock_t *rw) +{ + unsigned long tmp, oldval; + + __asm__ __volatile__ ( + "1: \n\t" + "movli.l @%2, %0 ! arch_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 arch_write_trylock(arch_rwlock_t *rw) +{ + unsigned long tmp, oldval; + + __asm__ __volatile__ ( + "1: \n\t" + "movli.l @%2, %0 ! arch_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)); +} + +#endif /* __ASM_SH_SPINLOCK_LLSC_H */ |