1/*
2 * include/asm-microblaze/system.h -- Low-level interrupt/thread ops
3 *
4 *  Copyright (C) 2003	John Williams (jwilliams@itee.uq.edu.au)
5 *			based upon microblaze version
6 *  Copyright (C) 2001	NEC Corporation
7 *  Copyright (C) 2001	Miles Bader <miles@gnu.org>
8 *
9 * This file is subject to the terms and conditions of the GNU General
10 * Public License.  See the file COPYING in the main directory of this
11 * archive for more details.
12 *
13 * Written by Miles Bader <miles@gnu.org>
14 * Microblaze port by John Williams
15 * Microblaze port by John Williams
16 */
17
18#ifndef __MICROBLAZE_SYSTEM_H__
19#define __MICROBLAZE_SYSTEM_H__
20
21#if 0
22#include <linux/linkage.h>
23#endif
24#include <asm/ptrace.h>
25
26#define MMU_SECTION_SIZE	(1 * 1024 * 1024)
27
28#define prepare_to_switch()	do { } while (0)
29
30/*
31 * switch_to(n) should switch tasks to task ptr, first checking that
32 * ptr isn't the current task, in which case it does nothing.
33 */
34struct thread_struct;
35extern void *switch_thread (struct thread_struct *last,
36			    struct thread_struct *next);
37#define switch_to(prev,next,last) do {					\
38	if (prev != next) {						\
39		(last) = switch_thread (&prev->thread, &next->thread);	\
40	}								\
41} while (0)
42
43
44/* Enable/disable interrupts.  */
45#define __sti() \
46{								\
47	register unsigned tmp;					\
48	__asm__ __volatile__ ("					\
49			mfs	%0, rmsr;			\
50			ori	%0, %0, 2;			\
51			mts	rmsr, %0"			\
52			: "=r" (tmp)				\
53			:					\
54			: "memory");				\
55}
56
57#define __cli() \
58{								\
59	register unsigned tmp;					\
60	__asm__ __volatile__ ("					\
61			mfs	%0, rmsr;			\
62			andi	%0, %0, ~2;			\
63			mts	rmsr, %0"			\
64			: "=r" (tmp)				\
65			:					\
66			: "memory");				\
67}
68
69#define __save_flags(flags) \
70	__asm__ __volatile__ ("mfs	%0, rmsr" : "=r" (flags))
71#define __restore_flags(flags) \
72	__asm__ __volatile__ ("mts	rmsr, %0" :: "r" (flags))
73
74#define __save_flags_cli(flags) \
75{								\
76	register unsigned tmp;					\
77	__asm__ __volatile__ ("					\
78			mfs	%0, rmsr;			\
79			andi	%1, %0, ~2;			\
80			mts	rmsr, %1;"			\
81			: "=r" (flags), "=r" (tmp)		\
82			:					\
83			: "memory");				\
84}
85
86#define __save_flags_sti(flags)					\
87{								\
88	register unsigned tmp;					\
89	__asm__ __volatile__ ("					\
90			mfs	%0, rmsr;			\
91			ori	%1, %0, 2;			\
92			mts	rmsr, %1;"			\
93			: "=r" (flags) ,"=r" (tmp)		\
94			:					\
95			: "memory");				\
96}
97
98/* For spinlocks etc */
99#define local_irq_save(flags)	__save_flags_cli (flags)
100#define local_irq_set(flags)	__save_flags_sti (flags)
101#define local_irq_restore(flags) __restore_flags (flags)
102#define local_irq_disable()	__cli ()
103#define local_irq_enable()	__sti ()
104
105#define cli()			__cli ()
106#define sti()			__sti ()
107#define save_flags(flags)	__save_flags (flags)
108#define restore_flags(flags)	__restore_flags (flags)
109#define save_flags_cli(flags)	__save_flags_cli (flags)
110
111/*
112 * Force strict CPU ordering.
113 * Not really required on microblaze...
114 */
115#define nop()			__asm__ __volatile__ ("nop")
116#define mb()			__asm__ __volatile__ ("nop" ::: "memory")
117#define rmb()			mb ()
118#define wmb()			mb ()
119#define set_mb(var, value)	do { var = value; mb(); } while (0)
120#define set_wmb(var, value)	do { var = value; wmb (); } while (0)
121
122#ifdef CONFIG_SMP
123#define smp_mb()	mb ()
124#define smp_rmb()	rmb ()
125#define smp_wmb()	wmb ()
126#else
127#define smp_mb()	barrier ()
128#define smp_rmb()	barrier ()
129#define smp_wmb()	barrier ()
130#endif
131
132#define xchg(ptr, with) \
133  ((__typeof__ (*(ptr)))__xchg ((unsigned long)(with), (ptr), sizeof (*(ptr))))
134#define tas(ptr) (xchg ((ptr), 1))
135
136static inline unsigned long __xchg(unsigned long with,
137				    __volatile__ void *ptr, int size)
138{
139	unsigned long tmp, flags;
140
141	save_flags_cli (flags);
142
143	switch (size) {
144	case 1:
145		tmp = *(unsigned char *)ptr;
146		*(unsigned char *)ptr = with;
147		break;
148	case 2:
149		tmp = *(unsigned short *)ptr;
150		*(unsigned short *)ptr = with;
151		break;
152	case 4:
153		tmp = *(unsigned long *)ptr;
154		*(unsigned long *)ptr = with;
155		break;
156	}
157
158	restore_flags (flags);
159
160	return tmp;
161}
162
163#endif /* __MICROBLAZE_SYSTEM_H__ */
164