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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#define tas(ptr) (xchg ((ptr), 1))
80
81static inline unsigned long __xchg (unsigned long with,
82 __volatile__ void *ptr, int size)
83{
84 unsigned long tmp, flags;
85
86 local_irq_save (flags);
87
88 switch (size) {
89 case 1:
90 tmp = *(unsigned char *)ptr;
91 *(unsigned char *)ptr = with;
92 break;
93 case 2:
94 tmp = *(unsigned short *)ptr;
95 *(unsigned short *)ptr = with;
96 break;
97 case 4:
98 tmp = *(unsigned long *)ptr;
99 *(unsigned long *)ptr = with;
100 break;
101 }
102
103 local_irq_restore (flags);
104
105 return tmp;
106}
107
108#define arch_align_stack(x) (x)
109
110#endif /* __V850_SYSTEM_H__ */