From 67d036327d60649df19966b3949e83b2ac94a678 Mon Sep 17 00:00:00 2001 From: "Ronald G. Minnich" Date: Thu, 15 Jan 2009 16:56:44 +0000 Subject: [PATCH] Right from Linux. I am not comfortable inserting our headers in linux files. Signed-off-by: Ronald G. Minnich Acked-by: Patrick Georgi git-svn-id: svn://coreboot.org/repository/coreboot-v3@1116 f3766cd6-281f-0410-b1cd-43a5c92072e9 --- include/arch/x86/arch/atomic.h | 70 ++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) create mode 100644 include/arch/x86/arch/atomic.h diff --git a/include/arch/x86/arch/atomic.h b/include/arch/x86/arch/atomic.h new file mode 100644 index 0000000000..cdc9b21462 --- /dev/null +++ b/include/arch/x86/arch/atomic.h @@ -0,0 +1,70 @@ +/* this implementation is from Linux. */ +#ifndef ARCH_ATOMIC_H +#define ARCH_ATOMIC_H + +/* + * Make sure gcc doesn't try to be clever and move things around + * on us. We need to use _exactly_ the address the user gave us, + * not some alias that contains the same information. + */ +struct atomic { volatile int counter; }; + +#define ATOMIC_INIT(i) { (i) } + +/* + * Atomic operations that C can't guarantee us. Useful for + * resource counting etc.. + */ + +/** + * atomic_read - read atomic variable + * @v: pointer of type struct atomic + * + * Atomically reads the value of @v. Note that the guaranteed + * useful range of an struct atomic is only 24 bits. + */ +#define atomic_read(v) ((v)->counter) + +/** + * atomic_set - set atomic variable + * @v: pointer of type struct atomic + * @i: required value + * + * Atomically sets the value of @v to @i. Note that the guaranteed + * useful range of an struct atomic is only 24 bits. + */ +#define atomic_set(v,i) (((v)->counter) = (i)) + +/** + * atomic_inc - increment atomic variable + * @v: pointer of type struct atomic + * + * Atomically increments @v by 1. Note that the guaranteed + * useful range of an struct atomic is only 24 bits. + */ +static __inline__ __attribute__((always_inline)) void atomic_inc(struct atomic *v) +{ + __asm__ __volatile__( + "lock ; incl %0" + :"=m" (v->counter) + :"m" (v->counter)); +} + +/** + * atomic_dec - decrement atomic variable + * @v: pointer of type struct atomic + * + * Atomically decrements @v by 1. Note that the guaranteed + * useful range of an struct atomic is only 24 bits. + */ +static __inline__ __attribute__((always_inline)) void atomic_dec(struct atomic *v) +{ + __asm__ __volatile__( + "lock ; decl %0" + :"=m" (v->counter) + :"m" (v->counter)); +} + + + +#endif /* ARCH_ATOMIC_H */