On Tue, Apr 28, 2015 at 6:48 AM, Simon Glass sjg@chromium.org wrote:
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 */
Reviewed-by: Bin Meng bmeng.cn@gmail.com