1. 根目录:
2. arch
3. frv
4. include
5. asm
6. cmpxchg.h

/* xchg and cmpxchg operation emulation for FR-V
 *
 * For an explanation of how atomic ops work in this arch, see:
 *   Documentation/frv/atomic-ops.txt
 *
 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */
#ifndef _ASM_CMPXCHG_H
#define _ASM_CMPXCHG_H

#include <linux/types.h>

/*****************************************************************************/
/*
 * exchange value with memory
 */
extern uint64_t __xchg_64(uint64_t i, volatile void *v);

#ifndef CONFIG_FRV_OUTOFLINE_ATOMIC_OPS

#define xchg(ptr, x)								\
({										\
	__typeof__(ptr) __xg_ptr = (ptr);					\
	__typeof__(*(ptr)) __xg_orig;						\
										\
	switch (sizeof(__xg_orig)) {						\
	case 4:									\
		asm volatile(							\
			"swap%I0 %M0,%1"					\
			: "+m"(*__xg_ptr), "=r"(__xg_orig)			\
			: "1"(x)						\
			: "memory"						\
			);							\
		break;								\
										\
	default:								\
		__xg_orig = (__typeof__(__xg_orig))0;				\
		asm volatile("break");						\
		break;								\
	}									\
										\
	__xg_orig;								\
})

#else

extern uint32_t __xchg_32(uint32_t i, volatile void *v);

#define xchg(ptr, x)										\
({												\
	__typeof__(ptr) __xg_ptr = (ptr);							\
	__typeof__(*(ptr)) __xg_orig;								\
												\
	switch (sizeof(__xg_orig)) {								\
	case 4: __xg_orig = (__typeof__(*(ptr))) __xchg_32((uint32_t) x, __xg_ptr);	break;	\
	default:										\
		__xg_orig = (__typeof__(__xg_orig))0;									\
		asm volatile("break");								\
		break;										\
	}											\
	__xg_orig;										\
})

#endif

#define tas(ptr) (xchg((ptr), 1))

/*****************************************************************************/
/*
 * compare and conditionally exchange value with memory
 * - if (*ptr == test) then orig = *ptr; *ptr = test;
 * - if (*ptr != test) then orig = *ptr;
 */
extern uint64_t __cmpxchg_64(uint64_t test, uint64_t new, volatile uint64_t *v);

#ifndef CONFIG_FRV_OUTOFLINE_ATOMIC_OPS

#define cmpxchg(ptr, test, new)							\
({										\
	__typeof__(ptr) __xg_ptr = (ptr);					\
	__typeof__(*(ptr)) __xg_orig, __xg_tmp;					\
	__typeof__(*(ptr)) __xg_test = (test);					\
	__typeof__(*(ptr)) __xg_new = (new);					\
										\
	switch (sizeof(__xg_orig)) {						\
	case 4:									\
		asm volatile(							\
			"0:						\n"	\
			"	orcc		gr0,gr0,gr0,icc3	\n"	\
			"	ckeq		icc3,cc7		\n"	\
			"	ld.p		%M0,%1			\n"	\
			"	orcr		cc7,cc7,cc3		\n"	\
			"	sub%I4cc	%1,%4,%2,icc0		\n"	\
			"	bne		icc0,#0,1f		\n"	\
			"	cst.p		%3,%M0		,cc3,#1	\n"	\
			"	corcc		gr29,gr29,gr0	,cc3,#1	\n"	\
			"	beq		icc3,#0,0b		\n"	\
			"1:						\n"	\
			: "+U"(*__xg_ptr), "=&r"(__xg_orig), "=&r"(__xg_tmp)	\
			: "r"(__xg_new), "NPr"(__xg_test)			\
			: "memory", "cc7", "cc3", "icc3", "icc0"		\
			);							\
		break;								\
										\
	default:								\
		__xg_orig = (__typeof__(__xg_orig))0;				\
		asm volatile("break");						\
		break;								\
	}									\
										\
	__xg_orig;								\
})

#else

extern uint32_t __cmpxchg_32(uint32_t *v, uint32_t test, uint32_t new);

#define cmpxchg(ptr, test, new)							\
({										\
	__typeof__(ptr) __xg_ptr = (ptr);					\
	__typeof__(*(ptr)) __xg_orig;						\
	__typeof__(*(ptr)) __xg_test = (test);					\
	__typeof__(*(ptr)) __xg_new = (new);					\
										\
	switch (sizeof(__xg_orig)) {						\
	case 4: __xg_orig = (__force __typeof__(*ptr))				\
			__cmpxchg_32((__force uint32_t *)__xg_ptr,		\
					 (__force uint32_t)__xg_test,		\
					 (__force uint32_t)__xg_new); break;	\
	default:								\
		__xg_orig = (__typeof__(__xg_orig))0;				\
		asm volatile("break");						\
		break;								\
	}									\
										\
	__xg_orig;								\
})

#endif

#include <asm-generic/cmpxchg-local.h>

static inline unsigned long __cmpxchg_local(volatile void *ptr,
				      unsigned long old,
				      unsigned long new, int size)
{
	switch (size) {
	case 4:
		return cmpxchg((unsigned long *)ptr, old, new);
	default:
		return __cmpxchg_local_generic(ptr, old, new, size);
	}

	return old;
}

/*
 * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
 * them available.
 */
#define cmpxchg_local(ptr, o, n)				  	\
	((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o),	\
			(unsigned long)(n), sizeof(*(ptr))))
#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))

#endif /* _ASM_CMPXCHG_H */