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Diffstat (limited to 'arch/arc/include/asm/atomic.h')
| -rw-r--r-- | arch/arc/include/asm/atomic.h | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/arch/arc/include/asm/atomic.h b/arch/arc/include/asm/atomic.h new file mode 100644 index 000000000..20b7dc179 --- /dev/null +++ b/arch/arc/include/asm/atomic.h @@ -0,0 +1,191 @@ +/* + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#ifndef _ASM_ARC_ATOMIC_H +#define _ASM_ARC_ATOMIC_H + +#ifndef __ASSEMBLY__ + +#include <linux/types.h> +#include <linux/compiler.h> +#include <asm/cmpxchg.h> +#include <asm/barrier.h> +#include <asm/smp.h> + +#define atomic_read(v) ((v)->counter) + +#ifdef CONFIG_ARC_HAS_LLSC + +#define atomic_set(v, i) (((v)->counter) = (i)) + +#define ATOMIC_OP(op, c_op, asm_op) \ +static inline void atomic_##op(int i, atomic_t *v) \ +{ \ + unsigned int temp; \ + \ + __asm__ __volatile__( \ + "1: llock %0, [%1] \n" \ + " " #asm_op " %0, %0, %2 \n" \ + " scond %0, [%1] \n" \ + " bnz 1b \n" \ + : "=&r"(temp) /* Early clobber, to prevent reg reuse */ \ + : "r"(&v->counter), "ir"(i) \ + : "cc"); \ +} \ + +#define ATOMIC_OP_RETURN(op, c_op, asm_op) \ +static inline int atomic_##op##_return(int i, atomic_t *v) \ +{ \ + unsigned int temp; \ + \ + /* \ + * Explicit full memory barrier needed before/after as \ + * LLOCK/SCOND thmeselves don't provide any such semantics \ + */ \ + smp_mb(); \ + \ + __asm__ __volatile__( \ + "1: llock %0, [%1] \n" \ + " " #asm_op " %0, %0, %2 \n" \ + " scond %0, [%1] \n" \ + " bnz 1b \n" \ + : "=&r"(temp) \ + : "r"(&v->counter), "ir"(i) \ + : "cc"); \ + \ + smp_mb(); \ + \ + return temp; \ +} + +#else /* !CONFIG_ARC_HAS_LLSC */ + +#ifndef CONFIG_SMP + + /* violating atomic_xxx API locking protocol in UP for optimization sake */ +#define atomic_set(v, i) (((v)->counter) = (i)) + +#else + +static inline void atomic_set(atomic_t *v, int i) +{ + /* + * Independent of hardware support, all of the atomic_xxx() APIs need + * to follow the same locking rules to make sure that a "hardware" + * atomic insn (e.g. LD) doesn't clobber an "emulated" atomic insn + * sequence + * + * Thus atomic_set() despite being 1 insn (and seemingly atomic) + * requires the locking. + */ + unsigned long flags; + + atomic_ops_lock(flags); + v->counter = i; + atomic_ops_unlock(flags); +} + +#endif + +/* + * Non hardware assisted Atomic-R-M-W + * Locking would change to irq-disabling only (UP) and spinlocks (SMP) + */ + +#define ATOMIC_OP(op, c_op, asm_op) \ +static inline void atomic_##op(int i, atomic_t *v) \ +{ \ + unsigned long flags; \ + \ + atomic_ops_lock(flags); \ + v->counter c_op i; \ + atomic_ops_unlock(flags); \ +} + +#define ATOMIC_OP_RETURN(op, c_op, asm_op) \ +static inline int atomic_##op##_return(int i, atomic_t *v) \ +{ \ + unsigned long flags; \ + unsigned long temp; \ + \ + /* \ + * spin lock/unlock provides the needed smp_mb() before/after \ + */ \ + atomic_ops_lock(flags); \ + temp = v->counter; \ + temp c_op i; \ + v->counter = temp; \ + atomic_ops_unlock(flags); \ + \ + return temp; \ +} + +#endif /* !CONFIG_ARC_HAS_LLSC */ + +#define ATOMIC_OPS(op, c_op, asm_op) \ + ATOMIC_OP(op, c_op, asm_op) \ + ATOMIC_OP_RETURN(op, c_op, asm_op) + +ATOMIC_OPS(add, +=, add) +ATOMIC_OPS(sub, -=, sub) +ATOMIC_OP(and, &=, and) + +#define atomic_clear_mask(mask, v) atomic_and(~(mask), (v)) + +#undef ATOMIC_OPS +#undef ATOMIC_OP_RETURN +#undef ATOMIC_OP + +/** + * __atomic_add_unless - add unless the number is a given value + * @v: pointer of type atomic_t + * @a: the amount to add to v... + * @u: ...unless v is equal to u. + * + * Atomically adds @a to @v, so long as it was not @u. + * Returns the old value of @v + */ +#define __atomic_add_unless(v, a, u) \ +({ \ + int c, old; \ + \ + /* \ + * Explicit full memory barrier needed before/after as \ + * LLOCK/SCOND thmeselves don't provide any such semantics \ + */ \ + smp_mb(); \ + \ + c = atomic_read(v); \ + while (c != (u) && (old = atomic_cmpxchg((v), c, c + (a))) != c)\ + c = old; \ + \ + smp_mb(); \ + \ + c; \ +}) + +#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) + +#define atomic_inc(v) atomic_add(1, v) +#define atomic_dec(v) atomic_sub(1, v) + +#define atomic_inc_and_test(v) (atomic_add_return(1, v) == 0) +#define atomic_dec_and_test(v) (atomic_sub_return(1, v) == 0) +#define atomic_inc_return(v) atomic_add_return(1, (v)) +#define atomic_dec_return(v) atomic_sub_return(1, (v)) +#define atomic_sub_and_test(i, v) (atomic_sub_return(i, v) == 0) + +#define atomic_add_negative(i, v) (atomic_add_return(i, v) < 0) + +#define ATOMIC_INIT(i) { (i) } + +#include <asm-generic/atomic64.h> + +#endif + +#endif |