Add a subset of this header file from Linux 4.0 to support atomic operations in U-Boot.
Signed-off-by: Simon Glass sjg@chromium.org ---
arch/x86/include/asm/atomic.h | 115 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 115 insertions(+) create mode 100644 arch/x86/include/asm/atomic.h
diff --git a/arch/x86/include/asm/atomic.h b/arch/x86/include/asm/atomic.h new file mode 100644 index 0000000..806f787 --- /dev/null +++ b/arch/x86/include/asm/atomic.h @@ -0,0 +1,115 @@ +#ifndef _ASM_X86_ATOMIC_H +#define _ASM_X86_ATOMIC_H + +#include <linux/compiler.h> +#include <linux/types.h> +#include <asm/processor.h> + +typedef struct { volatile int counter; } atomic_t; + +/* + * Atomic operations that C can't guarantee us. Useful for + * resource counting etc.. + */ + +#define ATOMIC_INIT(i) { (i) } + +/** + * atomic_read - read atomic variable + * @v: pointer of type atomic_t + * + * Atomically reads the value of @v. + */ +static inline int atomic_read(const atomic_t *v) +{ + return 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. + */ +static inline void atomic_set(atomic_t *v, int i) +{ + v->counter = i; +} + +/** + * atomic_add - add integer to atomic variable + * @i: integer value to add + * @v: pointer of type atomic_t + * + * Atomically adds @i to @v. + */ +static inline void atomic_add(int i, atomic_t *v) +{ + asm volatile(LOCK_PREFIX "addl %1,%0" + : "+m" (v->counter) + : "ir" (i)); +} + +/** + * atomic_sub - subtract integer from atomic variable + * @i: integer value to subtract + * @v: pointer of type atomic_t + * + * Atomically subtracts @i from @v. + */ +static inline void atomic_sub(int i, atomic_t *v) +{ + asm volatile(LOCK_PREFIX "subl %1,%0" + : "+m" (v->counter) + : "ir" (i)); +} + +/** + * atomic_inc - increment atomic variable + * @v: pointer of type atomic_t + * + * Atomically increments @v by 1. + */ +static inline void atomic_inc(atomic_t *v) +{ + asm volatile(LOCK_PREFIX "incl %0" + : "+m" (v->counter)); +} + +/** + * atomic_dec - decrement atomic variable + * @v: pointer of type atomic_t + * + * Atomically decrements @v by 1. + */ +static inline void atomic_dec(atomic_t *v) +{ + asm volatile(LOCK_PREFIX "decl %0" + : "+m" (v->counter)); +} + +/** + * atomic_inc_short - increment of a short integer + * @v: pointer to type int + * + * Atomically adds 1 to @v + * Returns the new value of @u + */ +static inline short int atomic_inc_short(short int *v) +{ + asm(LOCK_PREFIX "addw $1, %0" : "+m" (*v)); + return *v; +} + +/* These are x86-specific, used by some header files */ +#define atomic_clear_mask(mask, addr) \ + asm volatile(LOCK_PREFIX "andl %0,%1" \ + : : "r" (~(mask)), "m" (*(addr)) : "memory") + +#define atomic_set_mask(mask, addr) \ + asm volatile(LOCK_PREFIX "orl %0,%1" \ + : : "r" ((unsigned)(mask)), "m" (*(addr)) \ + : "memory") + +#endif /* _ASM_X86_ATOMIC_H */