| /* |
| * 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) ACCESS_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) ((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; \ |
| } |
| |
| #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; \ |
| } |
| |
| #endif /* XCHAL_HAVE_S32C1I */ |
| |
| #define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op) |
| |
| ATOMIC_OPS(add) |
| ATOMIC_OPS(sub) |
| |
| #undef ATOMIC_OPS |
| #undef ATOMIC_OP_RETURN |
| #undef ATOMIC_OP |
| |
| /** |
| * atomic_sub_and_test - subtract value from variable and test result |
| * @i: integer value to subtract |
| * @v: pointer of type atomic_t |
| * |
| * Atomically subtracts @i from @v and returns |
| * true if the result is zero, or false for all |
| * other cases. |
| */ |
| #define atomic_sub_and_test(i,v) (atomic_sub_return((i),(v)) == 0) |
| |
| /** |
| * atomic_inc - increment atomic variable |
| * @v: pointer of type atomic_t |
| * |
| * Atomically increments @v by 1. |
| */ |
| #define atomic_inc(v) atomic_add(1,(v)) |
| |
| /** |
| * atomic_inc - increment atomic variable |
| * @v: pointer of type atomic_t |
| * |
| * Atomically increments @v by 1. |
| */ |
| #define atomic_inc_return(v) atomic_add_return(1,(v)) |
| |
| /** |
| * atomic_dec - decrement atomic variable |
| * @v: pointer of type atomic_t |
| * |
| * Atomically decrements @v by 1. |
| */ |
| #define atomic_dec(v) atomic_sub(1,(v)) |
| |
| /** |
| * atomic_dec_return - decrement atomic variable |
| * @v: pointer of type atomic_t |
| * |
| * Atomically decrements @v by 1. |
| */ |
| #define atomic_dec_return(v) atomic_sub_return(1,(v)) |
| |
| /** |
| * atomic_dec_and_test - decrement and test |
| * @v: pointer of type atomic_t |
| * |
| * Atomically decrements @v by 1 and |
| * returns true if the result is 0, or false for all other |
| * cases. |
| */ |
| #define atomic_dec_and_test(v) (atomic_sub_return(1,(v)) == 0) |
| |
| /** |
| * atomic_inc_and_test - increment and test |
| * @v: pointer of type atomic_t |
| * |
| * Atomically increments @v by 1 |
| * and returns true if the result is zero, or false for all |
| * other cases. |
| */ |
| #define atomic_inc_and_test(v) (atomic_add_return(1,(v)) == 0) |
| |
| /** |
| * atomic_add_negative - add and test if negative |
| * @v: pointer of type atomic_t |
| * @i: integer value to add |
| * |
| * Atomically adds @i to @v and returns true |
| * if the result is negative, or false when |
| * result is greater than or equal to zero. |
| */ |
| #define atomic_add_negative(i,v) (atomic_add_return((i),(v)) < 0) |
| |
| #define atomic_cmpxchg(v, o, n) ((int)cmpxchg(&((v)->counter), (o), (n))) |
| #define atomic_xchg(v, new) (xchg(&((v)->counter), new)) |
| |
| /** |
| * __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. |
| */ |
| static __inline__ int __atomic_add_unless(atomic_t *v, int a, int u) |
| { |
| int c, old; |
| c = atomic_read(v); |
| for (;;) { |
| if (unlikely(c == (u))) |
| break; |
| old = atomic_cmpxchg((v), c, c + (a)); |
| if (likely(old == c)) |
| break; |
| c = old; |
| } |
| return c; |
| } |
| |
| |
| static inline void atomic_clear_mask(unsigned int mask, atomic_t *v) |
| { |
| #if XCHAL_HAVE_S32C1I |
| unsigned long tmp; |
| int result; |
| |
| __asm__ __volatile__( |
| "1: l32i %1, %3, 0\n" |
| " wsr %1, scompare1\n" |
| " and %0, %1, %2\n" |
| " s32c1i %0, %3, 0\n" |
| " bne %0, %1, 1b\n" |
| : "=&a" (result), "=&a" (tmp) |
| : "a" (~mask), "a" (v) |
| : "memory" |
| ); |
| #else |
| unsigned int all_f = -1; |
| unsigned int vval; |
| |
| __asm__ __volatile__( |
| " rsil a15,"__stringify(TOPLEVEL)"\n" |
| " l32i %0, %2, 0\n" |
| " xor %1, %4, %3\n" |
| " and %0, %0, %4\n" |
| " s32i %0, %2, 0\n" |
| " wsr a15, ps\n" |
| " rsync\n" |
| : "=&a" (vval), "=a" (mask) |
| : "a" (v), "a" (all_f), "1" (mask) |
| : "a15", "memory" |
| ); |
| #endif |
| } |
| |
| static inline void atomic_set_mask(unsigned int mask, atomic_t *v) |
| { |
| #if XCHAL_HAVE_S32C1I |
| unsigned long tmp; |
| int result; |
| |
| __asm__ __volatile__( |
| "1: l32i %1, %3, 0\n" |
| " wsr %1, scompare1\n" |
| " or %0, %1, %2\n" |
| " s32c1i %0, %3, 0\n" |
| " bne %0, %1, 1b\n" |
| : "=&a" (result), "=&a" (tmp) |
| : "a" (mask), "a" (v) |
| : "memory" |
| ); |
| #else |
| unsigned int vval; |
| |
| __asm__ __volatile__( |
| " rsil a15,"__stringify(TOPLEVEL)"\n" |
| " l32i %0, %2, 0\n" |
| " or %0, %0, %1\n" |
| " s32i %0, %2, 0\n" |
| " wsr a15, ps\n" |
| " rsync\n" |
| : "=&a" (vval) |
| : "a" (mask), "a" (v) |
| : "a15", "memory" |
| ); |
| #endif |
| } |
| |
| #endif /* __KERNEL__ */ |
| |
| #endif /* _XTENSA_ATOMIC_H */ |