b551173b73
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> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
116 lines
2.4 KiB
C
116 lines
2.4 KiB
C
#ifndef _ASM_X86_ATOMIC_H
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#define _ASM_X86_ATOMIC_H
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#include <linux/compiler.h>
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#include <linux/types.h>
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#include <asm/processor.h>
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typedef struct { volatile int counter; } atomic_t;
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/*
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* Atomic operations that C can't guarantee us. Useful for
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* resource counting etc..
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*/
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#define ATOMIC_INIT(i) { (i) }
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/**
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* atomic_read - read atomic variable
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* @v: pointer of type atomic_t
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*
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* Atomically reads the value of @v.
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*/
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static inline int atomic_read(const atomic_t *v)
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{
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return ACCESS_ONCE((v)->counter);
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}
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/**
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* atomic_set - set atomic variable
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* @v: pointer of type atomic_t
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* @i: required value
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*
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* Atomically sets the value of @v to @i.
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*/
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static inline void atomic_set(atomic_t *v, int i)
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{
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v->counter = i;
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}
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/**
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* atomic_add - add integer to atomic variable
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* @i: integer value to add
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* @v: pointer of type atomic_t
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*
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* Atomically adds @i to @v.
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*/
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static inline void atomic_add(int i, atomic_t *v)
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{
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asm volatile(LOCK_PREFIX "addl %1,%0"
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: "+m" (v->counter)
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: "ir" (i));
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}
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/**
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* atomic_sub - subtract integer from atomic variable
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* @i: integer value to subtract
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* @v: pointer of type atomic_t
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*
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* Atomically subtracts @i from @v.
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*/
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static inline void atomic_sub(int i, atomic_t *v)
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{
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asm volatile(LOCK_PREFIX "subl %1,%0"
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: "+m" (v->counter)
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: "ir" (i));
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}
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/**
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* atomic_inc - increment atomic variable
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* @v: pointer of type atomic_t
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*
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* Atomically increments @v by 1.
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*/
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static inline void atomic_inc(atomic_t *v)
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{
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asm volatile(LOCK_PREFIX "incl %0"
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: "+m" (v->counter));
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}
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/**
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* atomic_dec - decrement atomic variable
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* @v: pointer of type atomic_t
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*
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* Atomically decrements @v by 1.
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*/
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static inline void atomic_dec(atomic_t *v)
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{
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asm volatile(LOCK_PREFIX "decl %0"
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: "+m" (v->counter));
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}
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/**
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* atomic_inc_short - increment of a short integer
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* @v: pointer to type int
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*
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* Atomically adds 1 to @v
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* Returns the new value of @u
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*/
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static inline short int atomic_inc_short(short int *v)
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{
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asm(LOCK_PREFIX "addw $1, %0" : "+m" (*v));
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return *v;
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}
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/* These are x86-specific, used by some header files */
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#define atomic_clear_mask(mask, addr) \
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asm volatile(LOCK_PREFIX "andl %0,%1" \
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: : "r" (~(mask)), "m" (*(addr)) : "memory")
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#define atomic_set_mask(mask, addr) \
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asm volatile(LOCK_PREFIX "orl %0,%1" \
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: : "r" ((unsigned)(mask)), "m" (*(addr)) \
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: "memory")
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#endif /* _ASM_X86_ATOMIC_H */
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