1/*
2 * include/asm-v850/system.h -- Low-level interrupt/thread ops
3 *
4 *  Copyright (C) 2001,02,03  NEC Electronics Corporation
5 *  Copyright (C) 2001,02,03  Miles Bader <miles@gnu.org>
6 *
7 * This file is subject to the terms and conditions of the GNU General
8 * Public License.  See the file COPYING in the main directory of this
9 * archive for more details.
10 *
11 * Written by Miles Bader <miles@gnu.org>
12 */
13
14#ifndef __V850_SYSTEM_H__
15#define __V850_SYSTEM_H__
16
17#include <linux/linkage.h>
18#include <asm/ptrace.h>
19
20
21/*
22 * switch_to(n) should switch tasks to task ptr, first checking that
23 * ptr isn't the current task, in which case it does nothing.
24 */
25struct thread_struct;
26extern void *switch_thread (struct thread_struct *last,
27			    struct thread_struct *next);
28#define switch_to(prev,next,last)					      \
29  do {									      \
30        if (prev != next) {						      \
31 		(last) = switch_thread (&prev->thread, &next->thread);	      \
32	}								      \
33  } while (0)
34
35
36/* Enable/disable interrupts.  */
37#define local_irq_enable()	__asm__ __volatile__ ("ei")
38#define local_irq_disable()	__asm__ __volatile__ ("di")
39
40#define local_save_flags(flags) \
41  __asm__ __volatile__ ("stsr %1, %0" : "=r" (flags) : "i" (SR_PSW))
42#define local_restore_flags(flags) \
43  __asm__ __volatile__ ("ldsr %0, %1" :: "r" (flags), "i" (SR_PSW))
44
45/* For spinlocks etc */
46#define	local_irq_save(flags) \
47  do { local_save_flags (flags); local_irq_disable (); } while (0)
48#define local_irq_restore(flags) \
49  local_restore_flags (flags);
50
51
52static inline int irqs_disabled (void)
53{
54	unsigned flags;
55	local_save_flags (flags);
56	return !!(flags & 0x20);
57}
58
59
60/*
61 * Force strict CPU ordering.
62 * Not really required on v850...
63 */
64#define nop()			__asm__ __volatile__ ("nop")
65#define mb()			__asm__ __volatile__ ("" ::: "memory")
66#define rmb()			mb ()
67#define wmb()			mb ()
68#define read_barrier_depends()	((void)0)
69#define set_rmb(var, value)	do { xchg (&var, value); } while (0)
70#define set_mb(var, value)	set_rmb (var, value)
71
72#define smp_mb()	mb ()
73#define smp_rmb()	rmb ()
74#define smp_wmb()	wmb ()
75#define smp_read_barrier_depends()	read_barrier_depends()
76
77#define xchg(ptr, with) \
78  ((__typeof__ (*(ptr)))__xchg ((unsigned long)(with), (ptr), sizeof (*(ptr))))
79
80static inline unsigned long __xchg (unsigned long with,
81				    __volatile__ void *ptr, int size)
82{
83	unsigned long tmp, flags;
84
85	local_irq_save (flags);
86
87	switch (size) {
88	case 1:
89		tmp = *(unsigned char *)ptr;
90		*(unsigned char *)ptr = with;
91		break;
92	case 2:
93		tmp = *(unsigned short *)ptr;
94		*(unsigned short *)ptr = with;
95		break;
96	case 4:
97		tmp = *(unsigned long *)ptr;
98		*(unsigned long *)ptr = with;
99		break;
100	}
101
102	local_irq_restore (flags);
103
104	return tmp;
105}
106
107#define arch_align_stack(x) (x)
108
109#endif /* __V850_SYSTEM_H__ */
110