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Diffstat (limited to 'arch/xtensa/include/asm/atomic.h')
| -rw-r--r-- | arch/xtensa/include/asm/atomic.h | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/arch/xtensa/include/asm/atomic.h b/arch/xtensa/include/asm/atomic.h new file mode 100644 index 000000000..7de0149e1 --- /dev/null +++ b/arch/xtensa/include/asm/atomic.h @@ -0,0 +1,205 @@ +/* + * include/asm-xtensa/atomic.h + * + * Atomic operations that C can't guarantee us. Useful for resource counting.. + * + * 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. + * + * Copyright (C) 2001 - 2008 Tensilica Inc. + */ + +#ifndef _XTENSA_ATOMIC_H +#define _XTENSA_ATOMIC_H + +#include <linux/stringify.h> +#include <linux/types.h> + +#ifdef __KERNEL__ +#include <asm/processor.h> +#include <asm/cmpxchg.h> +#include <asm/barrier.h> + +#define ATOMIC_INIT(i) { (i) } + +/* + * This Xtensa implementation assumes that the right mechanism + * for exclusion is for locking interrupts to level EXCM_LEVEL. + * + * Locking interrupts looks like this: + * + * rsil a15, TOPLEVEL + * <code> + * wsr a15, PS + * rsync + * + * Note that a15 is used here because the register allocation + * done by the compiler is not guaranteed and a window overflow + * may not occur between the rsil and wsr instructions. By using + * a15 in the rsil, the machine is guaranteed to be in a state + * where no register reference will cause an overflow. + */ + +/** + * atomic_read - read atomic variable + * @v: pointer of type atomic_t + * + * Atomically reads the value of @v. + */ +#define atomic_read(v) READ_ONCE((v)->counter) + +/** + * atomic_set - set atomic variable + * @v: pointer of type atomic_t + * @i: required value + * + * Atomically sets the value of @v to @i. + */ +#define atomic_set(v,i) WRITE_ONCE((v)->counter, (i)) + +#if XCHAL_HAVE_S32C1I +#define ATOMIC_OP(op) \ +static inline void atomic_##op(int i, atomic_t * v) \ +{ \ + unsigned long tmp; \ + int result; \ + \ + __asm__ __volatile__( \ + "1: l32i %1, %3, 0\n" \ + " wsr %1, scompare1\n" \ + " " #op " %0, %1, %2\n" \ + " s32c1i %0, %3, 0\n" \ + " bne %0, %1, 1b\n" \ + : "=&a" (result), "=&a" (tmp) \ + : "a" (i), "a" (v) \ + : "memory" \ + ); \ +} \ + +#define ATOMIC_OP_RETURN(op) \ +static inline int atomic_##op##_return(int i, atomic_t * v) \ +{ \ + unsigned long tmp; \ + int result; \ + \ + __asm__ __volatile__( \ + "1: l32i %1, %3, 0\n" \ + " wsr %1, scompare1\n" \ + " " #op " %0, %1, %2\n" \ + " s32c1i %0, %3, 0\n" \ + " bne %0, %1, 1b\n" \ + " " #op " %0, %0, %2\n" \ + : "=&a" (result), "=&a" (tmp) \ + : "a" (i), "a" (v) \ + : "memory" \ + ); \ + \ + return result; \ +} + +#define ATOMIC_FETCH_OP(op) \ +static inline int atomic_fetch_##op(int i, atomic_t * v) \ +{ \ + unsigned long tmp; \ + int result; \ + \ + __asm__ __volatile__( \ + "1: l32i %1, %3, 0\n" \ + " wsr %1, scompare1\n" \ + " " #op " %0, %1, %2\n" \ + " s32c1i %0, %3, 0\n" \ + " bne %0, %1, 1b\n" \ + : "=&a" (result), "=&a" (tmp) \ + : "a" (i), "a" (v) \ + : "memory" \ + ); \ + \ + return result; \ +} + +#else /* XCHAL_HAVE_S32C1I */ + +#define ATOMIC_OP(op) \ +static inline void atomic_##op(int i, atomic_t * v) \ +{ \ + unsigned int vval; \ + \ + __asm__ __volatile__( \ + " rsil a15, "__stringify(TOPLEVEL)"\n"\ + " l32i %0, %2, 0\n" \ + " " #op " %0, %0, %1\n" \ + " s32i %0, %2, 0\n" \ + " wsr a15, ps\n" \ + " rsync\n" \ + : "=&a" (vval) \ + : "a" (i), "a" (v) \ + : "a15", "memory" \ + ); \ +} \ + +#define ATOMIC_OP_RETURN(op) \ +static inline int atomic_##op##_return(int i, atomic_t * v) \ +{ \ + unsigned int vval; \ + \ + __asm__ __volatile__( \ + " rsil a15,"__stringify(TOPLEVEL)"\n" \ + " l32i %0, %2, 0\n" \ + " " #op " %0, %0, %1\n" \ + " s32i %0, %2, 0\n" \ + " wsr a15, ps\n" \ + " rsync\n" \ + : "=&a" (vval) \ + : "a" (i), "a" (v) \ + : "a15", "memory" \ + ); \ + \ + return vval; \ +} + +#define ATOMIC_FETCH_OP(op) \ +static inline int atomic_fetch_##op(int i, atomic_t * v) \ +{ \ + unsigned int tmp, vval; \ + \ + __asm__ __volatile__( \ + " rsil a15,"__stringify(TOPLEVEL)"\n" \ + " l32i %0, %3, 0\n" \ + " " #op " %1, %0, %2\n" \ + " s32i %1, %3, 0\n" \ + " wsr a15, ps\n" \ + " rsync\n" \ + : "=&a" (vval), "=&a" (tmp) \ + : "a" (i), "a" (v) \ + : "a15", "memory" \ + ); \ + \ + return vval; \ +} + +#endif /* XCHAL_HAVE_S32C1I */ + +#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_FETCH_OP(op) ATOMIC_OP_RETURN(op) + +ATOMIC_OPS(add) +ATOMIC_OPS(sub) + +#undef ATOMIC_OPS +#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_FETCH_OP(op) + +ATOMIC_OPS(and) +ATOMIC_OPS(or) +ATOMIC_OPS(xor) + +#undef ATOMIC_OPS +#undef ATOMIC_FETCH_OP +#undef ATOMIC_OP_RETURN +#undef ATOMIC_OP + +#define atomic_cmpxchg(v, o, n) ((int)cmpxchg(&((v)->counter), (o), (n))) +#define atomic_xchg(v, new) (xchg(&((v)->counter), new)) + +#endif /* __KERNEL__ */ + +#endif /* _XTENSA_ATOMIC_H */ |