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diff --git a/arch/mips/include/asm/octeon/cvmx-spinlock.h b/arch/mips/include/asm/octeon/cvmx-spinlock.h
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1/***********************license start***************
2 * Author: Cavium Networks
3 *
4 * Contact: support@caviumnetworks.com
5 * This file is part of the OCTEON SDK
6 *
7 * Copyright (c) 2003-2008 Cavium Networks
8 *
9 * This file is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License, Version 2, as
11 * published by the Free Software Foundation.
12 *
13 * This file is distributed in the hope that it will be useful, but
14 * AS-IS and WITHOUT ANY WARRANTY; without even the implied warranty
15 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, TITLE, or
16 * NONINFRINGEMENT. See the GNU General Public License for more
17 * details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with this file; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
22 * or visit http://www.gnu.org/licenses/.
23 *
24 * This file may also be available under a different license from Cavium.
25 * Contact Cavium Networks for more information
26 ***********************license end**************************************/
27
28/**
29 * Implementation of spinlocks for Octeon CVMX. Although similar in
30 * function to Linux kernel spinlocks, they are not compatible.
31 * Octeon CVMX spinlocks are only used to synchronize with the boot
32 * monitor and other non-Linux programs running in the system.
33 */
34
35#ifndef __CVMX_SPINLOCK_H__
36#define __CVMX_SPINLOCK_H__
37
38#include "cvmx-asm.h"
39
40/* Spinlocks for Octeon */
41
42/* define these to enable recursive spinlock debugging */
43/*#define CVMX_SPINLOCK_DEBUG */
44
45/**
46 * Spinlocks for Octeon CVMX
47 */
48typedef struct {
49 volatile uint32_t value;
50} cvmx_spinlock_t;
51
52/* note - macros not expanded in inline ASM, so values hardcoded */
53#define CVMX_SPINLOCK_UNLOCKED_VAL 0
54#define CVMX_SPINLOCK_LOCKED_VAL 1
55
56#define CVMX_SPINLOCK_UNLOCKED_INITIALIZER {CVMX_SPINLOCK_UNLOCKED_VAL}
57
58/**
59 * Initialize a spinlock
60 *
61 * @lock: Lock to initialize
62 */
63static inline void cvmx_spinlock_init(cvmx_spinlock_t *lock)
64{
65 lock->value = CVMX_SPINLOCK_UNLOCKED_VAL;
66}
67
68/**
69 * Return non-zero if the spinlock is currently locked
70 *
71 * @lock: Lock to check
72 * Returns Non-zero if locked
73 */
74static inline int cvmx_spinlock_locked(cvmx_spinlock_t *lock)
75{
76 return lock->value != CVMX_SPINLOCK_UNLOCKED_VAL;
77}
78
79/**
80 * Releases lock
81 *
82 * @lock: pointer to lock structure
83 */
84static inline void cvmx_spinlock_unlock(cvmx_spinlock_t *lock)
85{
86 CVMX_SYNCWS;
87 lock->value = 0;
88 CVMX_SYNCWS;
89}
90
91/**
92 * Attempts to take the lock, but does not spin if lock is not available.
93 * May take some time to acquire the lock even if it is available
94 * due to the ll/sc not succeeding.
95 *
96 * @lock: pointer to lock structure
97 *
98 * Returns 0: lock successfully taken
99 * 1: lock not taken, held by someone else
100 * These return values match the Linux semantics.
101 */
102
103static inline unsigned int cvmx_spinlock_trylock(cvmx_spinlock_t *lock)
104{
105 unsigned int tmp;
106
107 __asm__ __volatile__(".set noreorder \n"
108 "1: ll %[tmp], %[val] \n"
109 /* if lock held, fail immediately */
110 " bnez %[tmp], 2f \n"
111 " li %[tmp], 1 \n"
112 " sc %[tmp], %[val] \n"
113 " beqz %[tmp], 1b \n"
114 " li %[tmp], 0 \n"
115 "2: \n"
116 ".set reorder \n" :
117 [val] "+m"(lock->value), [tmp] "=&r"(tmp)
118 : : "memory");
119
120 return tmp != 0; /* normalize to 0 or 1 */
121}
122
123/**
124 * Gets lock, spins until lock is taken
125 *
126 * @lock: pointer to lock structure
127 */
128static inline void cvmx_spinlock_lock(cvmx_spinlock_t *lock)
129{
130 unsigned int tmp;
131
132 __asm__ __volatile__(".set noreorder \n"
133 "1: ll %[tmp], %[val] \n"
134 " bnez %[tmp], 1b \n"
135 " li %[tmp], 1 \n"
136 " sc %[tmp], %[val] \n"
137 " beqz %[tmp], 1b \n"
138 " nop \n"
139 ".set reorder \n" :
140 [val] "+m"(lock->value), [tmp] "=&r"(tmp)
141 : : "memory");
142
143}
144
145/** ********************************************************************
146 * Bit spinlocks
147 * These spinlocks use a single bit (bit 31) of a 32 bit word for locking.
148 * The rest of the bits in the word are left undisturbed. This enables more
149 * compact data structures as only 1 bit is consumed for the lock.
150 *
151 */
152
153/**
154 * Gets lock, spins until lock is taken
155 * Preserves the low 31 bits of the 32 bit
156 * word used for the lock.
157 *
158 *
159 * @word: word to lock bit 31 of
160 */
161static inline void cvmx_spinlock_bit_lock(uint32_t *word)
162{
163 unsigned int tmp;
164 unsigned int sav;
165
166 __asm__ __volatile__(".set noreorder \n"
167 ".set noat \n"
168 "1: ll %[tmp], %[val] \n"
169 " bbit1 %[tmp], 31, 1b \n"
170 " li $at, 1 \n"
171 " ins %[tmp], $at, 31, 1 \n"
172 " sc %[tmp], %[val] \n"
173 " beqz %[tmp], 1b \n"
174 " nop \n"
175 ".set at \n"
176 ".set reorder \n" :
177 [val] "+m"(*word), [tmp] "=&r"(tmp), [sav] "=&r"(sav)
178 : : "memory");
179
180}
181
182/**
183 * Attempts to get lock, returns immediately with success/failure
184 * Preserves the low 31 bits of the 32 bit
185 * word used for the lock.
186 *
187 *
188 * @word: word to lock bit 31 of
189 * Returns 0: lock successfully taken
190 * 1: lock not taken, held by someone else
191 * These return values match the Linux semantics.
192 */
193static inline unsigned int cvmx_spinlock_bit_trylock(uint32_t *word)
194{
195 unsigned int tmp;
196
197 __asm__ __volatile__(".set noreorder\n\t"
198 ".set noat\n"
199 "1: ll %[tmp], %[val] \n"
200 /* if lock held, fail immediately */
201 " bbit1 %[tmp], 31, 2f \n"
202 " li $at, 1 \n"
203 " ins %[tmp], $at, 31, 1 \n"
204 " sc %[tmp], %[val] \n"
205 " beqz %[tmp], 1b \n"
206 " li %[tmp], 0 \n"
207 "2: \n"
208 ".set at \n"
209 ".set reorder \n" :
210 [val] "+m"(*word), [tmp] "=&r"(tmp)
211 : : "memory");
212
213 return tmp != 0; /* normalize to 0 or 1 */
214}
215
216/**
217 * Releases bit lock
218 *
219 * Unconditionally clears bit 31 of the lock word. Note that this is
220 * done non-atomically, as this implementation assumes that the rest
221 * of the bits in the word are protected by the lock.
222 *
223 * @word: word to unlock bit 31 in
224 */
225static inline void cvmx_spinlock_bit_unlock(uint32_t *word)
226{
227 CVMX_SYNCWS;
228 *word &= ~(1UL << 31);
229 CVMX_SYNCWS;
230}
231
232#endif /* __CVMX_SPINLOCK_H__ */
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