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 <asm/octeon/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__ */
233