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/* Copyright 2014 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/* Atomic operations for ARMv6-M */
#ifndef __CROS_EC_ATOMIC_H
#define __CROS_EC_ATOMIC_H
#include "common.h"
typedef int atomic_t;
typedef atomic_t atomic_val_t;
/**
* Implements atomic arithmetic operations on 32-bit integers.
*
* There is no load/store exclusive on ARMv6-M, just disable interrupts
*/
#define ATOMIC_OP(asm_op, a, v) \
({ \
uint32_t reg0, reg1; \
\
__asm__ __volatile__(" cpsid i\n" \
" ldr %0, [%2]\n" \
" mov %1, %0\n" \
#asm_op" %0, %0, %3\n" \
" str %0, [%2]\n" \
" cpsie i\n" \
: "=&l"(reg0), "=&l"(reg1) \
: "l"(a), "r"(v) \
: "cc", "memory"); \
reg1; \
})
static inline atomic_val_t atomic_clear_bits(atomic_t *addr, atomic_val_t bits)
{
return ATOMIC_OP(bic, addr, bits);
}
static inline atomic_val_t atomic_or(atomic_t *addr, atomic_val_t bits)
{
return ATOMIC_OP(orr, addr, bits);
}
static inline atomic_val_t atomic_add(atomic_t *addr, atomic_val_t value)
{
return ATOMIC_OP(add, addr, value);
}
static inline atomic_val_t atomic_sub(atomic_t *addr, atomic_val_t value)
{
return ATOMIC_OP(sub, addr, value);
}
static inline atomic_val_t atomic_clear(atomic_t *addr)
{
atomic_t ret;
__asm__ __volatile__(" mov %2, #0\n"
" cpsid i\n"
" ldr %0, [%1]\n"
" str %2, [%1]\n"
" cpsie i\n"
: "=&l" (ret)
: "l" (addr), "r" (0)
: "cc", "memory");
return ret;
}
#endif /* __CROS_EC_ATOMIC_H */
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