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bd9a4c7d OBC |
1 | /* |
2 | * Hardware spinlock public header | |
3 | * | |
4 | * Copyright (C) 2010 Texas Instruments Incorporated - http://www.ti.com | |
5 | * | |
6 | * Contact: Ohad Ben-Cohen <ohad@wizery.com> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify it | |
9 | * under the terms of the GNU General Public License version 2 as published | |
10 | * by the Free Software Foundation. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | * GNU General Public License for more details. | |
16 | */ | |
17 | ||
18 | #ifndef __LINUX_HWSPINLOCK_H | |
19 | #define __LINUX_HWSPINLOCK_H | |
20 | ||
21 | #include <linux/err.h> | |
22 | #include <linux/sched.h> | |
23 | ||
24 | /* hwspinlock mode argument */ | |
25 | #define HWLOCK_IRQSTATE 0x01 /* Disable interrupts, save state */ | |
26 | #define HWLOCK_IRQ 0x02 /* Disable interrupts, don't save state */ | |
27 | ||
313162d0 | 28 | struct device; |
fb7737e9 | 29 | struct device_node; |
bd9a4c7d | 30 | struct hwspinlock; |
300bab97 OBC |
31 | struct hwspinlock_device; |
32 | struct hwspinlock_ops; | |
bd9a4c7d | 33 | |
c3c1250e OBC |
34 | /** |
35 | * struct hwspinlock_pdata - platform data for hwspinlock drivers | |
36 | * @base_id: base id for this hwspinlock device | |
37 | * | |
38 | * hwspinlock devices provide system-wide hardware locks that are used | |
39 | * by remote processors that have no other way to achieve synchronization. | |
40 | * | |
41 | * To achieve that, each physical lock must have a system-wide id number | |
42 | * that is agreed upon, otherwise remote processors can't possibly assume | |
43 | * they're using the same hardware lock. | |
44 | * | |
45 | * Usually boards have a single hwspinlock device, which provides several | |
46 | * hwspinlocks, and in this case, they can be trivially numbered 0 to | |
47 | * (num-of-locks - 1). | |
48 | * | |
49 | * In case boards have several hwspinlocks devices, a different base id | |
50 | * should be used for each hwspinlock device (they can't all use 0 as | |
51 | * a starting id!). | |
52 | * | |
53 | * This platform data structure should be used to provide the base id | |
54 | * for each device (which is trivially 0 when only a single hwspinlock | |
55 | * device exists). It can be shared between different platforms, hence | |
56 | * its location. | |
57 | */ | |
58 | struct hwspinlock_pdata { | |
59 | int base_id; | |
60 | }; | |
61 | ||
bd9a4c7d OBC |
62 | #if defined(CONFIG_HWSPINLOCK) || defined(CONFIG_HWSPINLOCK_MODULE) |
63 | ||
300bab97 OBC |
64 | int hwspin_lock_register(struct hwspinlock_device *bank, struct device *dev, |
65 | const struct hwspinlock_ops *ops, int base_id, int num_locks); | |
66 | int hwspin_lock_unregister(struct hwspinlock_device *bank); | |
bd9a4c7d OBC |
67 | struct hwspinlock *hwspin_lock_request(void); |
68 | struct hwspinlock *hwspin_lock_request_specific(unsigned int id); | |
69 | int hwspin_lock_free(struct hwspinlock *hwlock); | |
fb7737e9 | 70 | int of_hwspin_lock_get_id(struct device_node *np, int index); |
bd9a4c7d OBC |
71 | int hwspin_lock_get_id(struct hwspinlock *hwlock); |
72 | int __hwspin_lock_timeout(struct hwspinlock *, unsigned int, int, | |
73 | unsigned long *); | |
74 | int __hwspin_trylock(struct hwspinlock *, int, unsigned long *); | |
75 | void __hwspin_unlock(struct hwspinlock *, int, unsigned long *); | |
76 | ||
77 | #else /* !CONFIG_HWSPINLOCK */ | |
78 | ||
79 | /* | |
80 | * We don't want these functions to fail if CONFIG_HWSPINLOCK is not | |
81 | * enabled. We prefer to silently succeed in this case, and let the | |
82 | * code path get compiled away. This way, if CONFIG_HWSPINLOCK is not | |
83 | * required on a given setup, users will still work. | |
84 | * | |
85 | * The only exception is hwspin_lock_register/hwspin_lock_unregister, with which | |
86 | * we _do_ want users to fail (no point in registering hwspinlock instances if | |
87 | * the framework is not available). | |
88 | * | |
89 | * Note: ERR_PTR(-ENODEV) will still be considered a success for NULL-checking | |
90 | * users. Others, which care, can still check this with IS_ERR. | |
91 | */ | |
92 | static inline struct hwspinlock *hwspin_lock_request(void) | |
93 | { | |
94 | return ERR_PTR(-ENODEV); | |
95 | } | |
96 | ||
97 | static inline struct hwspinlock *hwspin_lock_request_specific(unsigned int id) | |
98 | { | |
99 | return ERR_PTR(-ENODEV); | |
100 | } | |
101 | ||
102 | static inline int hwspin_lock_free(struct hwspinlock *hwlock) | |
103 | { | |
104 | return 0; | |
105 | } | |
106 | ||
107 | static inline | |
108 | int __hwspin_lock_timeout(struct hwspinlock *hwlock, unsigned int to, | |
109 | int mode, unsigned long *flags) | |
110 | { | |
111 | return 0; | |
112 | } | |
113 | ||
114 | static inline | |
115 | int __hwspin_trylock(struct hwspinlock *hwlock, int mode, unsigned long *flags) | |
116 | { | |
117 | return 0; | |
118 | } | |
119 | ||
120 | static inline | |
121 | void __hwspin_unlock(struct hwspinlock *hwlock, int mode, unsigned long *flags) | |
122 | { | |
bd9a4c7d OBC |
123 | } |
124 | ||
fb7737e9 SA |
125 | static inline int of_hwspin_lock_get_id(struct device_node *np, int index) |
126 | { | |
127 | return 0; | |
128 | } | |
129 | ||
bd9a4c7d OBC |
130 | static inline int hwspin_lock_get_id(struct hwspinlock *hwlock) |
131 | { | |
132 | return 0; | |
133 | } | |
134 | ||
bd9a4c7d OBC |
135 | #endif /* !CONFIG_HWSPINLOCK */ |
136 | ||
137 | /** | |
138 | * hwspin_trylock_irqsave() - try to lock an hwspinlock, disable interrupts | |
139 | * @hwlock: an hwspinlock which we want to trylock | |
140 | * @flags: a pointer to where the caller's interrupt state will be saved at | |
141 | * | |
142 | * This function attempts to lock the underlying hwspinlock, and will | |
143 | * immediately fail if the hwspinlock is already locked. | |
144 | * | |
145 | * Upon a successful return from this function, preemption and local | |
146 | * interrupts are disabled (previous interrupts state is saved at @flags), | |
147 | * so the caller must not sleep, and is advised to release the hwspinlock | |
148 | * as soon as possible. | |
149 | * | |
150 | * Returns 0 if we successfully locked the hwspinlock, -EBUSY if | |
151 | * the hwspinlock was already taken, and -EINVAL if @hwlock is invalid. | |
152 | */ | |
153 | static inline | |
154 | int hwspin_trylock_irqsave(struct hwspinlock *hwlock, unsigned long *flags) | |
155 | { | |
156 | return __hwspin_trylock(hwlock, HWLOCK_IRQSTATE, flags); | |
157 | } | |
158 | ||
159 | /** | |
160 | * hwspin_trylock_irq() - try to lock an hwspinlock, disable interrupts | |
161 | * @hwlock: an hwspinlock which we want to trylock | |
162 | * | |
163 | * This function attempts to lock the underlying hwspinlock, and will | |
164 | * immediately fail if the hwspinlock is already locked. | |
165 | * | |
166 | * Upon a successful return from this function, preemption and local | |
167 | * interrupts are disabled, so the caller must not sleep, and is advised | |
168 | * to release the hwspinlock as soon as possible. | |
169 | * | |
170 | * Returns 0 if we successfully locked the hwspinlock, -EBUSY if | |
171 | * the hwspinlock was already taken, and -EINVAL if @hwlock is invalid. | |
172 | */ | |
173 | static inline int hwspin_trylock_irq(struct hwspinlock *hwlock) | |
174 | { | |
175 | return __hwspin_trylock(hwlock, HWLOCK_IRQ, NULL); | |
176 | } | |
177 | ||
178 | /** | |
179 | * hwspin_trylock() - attempt to lock a specific hwspinlock | |
180 | * @hwlock: an hwspinlock which we want to trylock | |
181 | * | |
182 | * This function attempts to lock an hwspinlock, and will immediately fail | |
183 | * if the hwspinlock is already taken. | |
184 | * | |
185 | * Upon a successful return from this function, preemption is disabled, | |
186 | * so the caller must not sleep, and is advised to release the hwspinlock | |
187 | * as soon as possible. This is required in order to minimize remote cores | |
188 | * polling on the hardware interconnect. | |
189 | * | |
190 | * Returns 0 if we successfully locked the hwspinlock, -EBUSY if | |
191 | * the hwspinlock was already taken, and -EINVAL if @hwlock is invalid. | |
192 | */ | |
193 | static inline int hwspin_trylock(struct hwspinlock *hwlock) | |
194 | { | |
195 | return __hwspin_trylock(hwlock, 0, NULL); | |
196 | } | |
197 | ||
198 | /** | |
199 | * hwspin_lock_timeout_irqsave() - lock hwspinlock, with timeout, disable irqs | |
200 | * @hwlock: the hwspinlock to be locked | |
201 | * @to: timeout value in msecs | |
202 | * @flags: a pointer to where the caller's interrupt state will be saved at | |
203 | * | |
204 | * This function locks the underlying @hwlock. If the @hwlock | |
205 | * is already taken, the function will busy loop waiting for it to | |
206 | * be released, but give up when @timeout msecs have elapsed. | |
207 | * | |
208 | * Upon a successful return from this function, preemption and local interrupts | |
209 | * are disabled (plus previous interrupt state is saved), so the caller must | |
210 | * not sleep, and is advised to release the hwspinlock as soon as possible. | |
211 | * | |
212 | * Returns 0 when the @hwlock was successfully taken, and an appropriate | |
213 | * error code otherwise (most notably an -ETIMEDOUT if the @hwlock is still | |
214 | * busy after @timeout msecs). The function will never sleep. | |
215 | */ | |
216 | static inline int hwspin_lock_timeout_irqsave(struct hwspinlock *hwlock, | |
217 | unsigned int to, unsigned long *flags) | |
218 | { | |
219 | return __hwspin_lock_timeout(hwlock, to, HWLOCK_IRQSTATE, flags); | |
220 | } | |
221 | ||
222 | /** | |
223 | * hwspin_lock_timeout_irq() - lock hwspinlock, with timeout, disable irqs | |
224 | * @hwlock: the hwspinlock to be locked | |
225 | * @to: timeout value in msecs | |
226 | * | |
227 | * This function locks the underlying @hwlock. If the @hwlock | |
228 | * is already taken, the function will busy loop waiting for it to | |
229 | * be released, but give up when @timeout msecs have elapsed. | |
230 | * | |
231 | * Upon a successful return from this function, preemption and local interrupts | |
232 | * are disabled so the caller must not sleep, and is advised to release the | |
233 | * hwspinlock as soon as possible. | |
234 | * | |
235 | * Returns 0 when the @hwlock was successfully taken, and an appropriate | |
236 | * error code otherwise (most notably an -ETIMEDOUT if the @hwlock is still | |
237 | * busy after @timeout msecs). The function will never sleep. | |
238 | */ | |
239 | static inline | |
240 | int hwspin_lock_timeout_irq(struct hwspinlock *hwlock, unsigned int to) | |
241 | { | |
242 | return __hwspin_lock_timeout(hwlock, to, HWLOCK_IRQ, NULL); | |
243 | } | |
244 | ||
245 | /** | |
246 | * hwspin_lock_timeout() - lock an hwspinlock with timeout limit | |
247 | * @hwlock: the hwspinlock to be locked | |
248 | * @to: timeout value in msecs | |
249 | * | |
250 | * This function locks the underlying @hwlock. If the @hwlock | |
251 | * is already taken, the function will busy loop waiting for it to | |
252 | * be released, but give up when @timeout msecs have elapsed. | |
253 | * | |
254 | * Upon a successful return from this function, preemption is disabled | |
255 | * so the caller must not sleep, and is advised to release the hwspinlock | |
256 | * as soon as possible. | |
257 | * This is required in order to minimize remote cores polling on the | |
258 | * hardware interconnect. | |
259 | * | |
260 | * Returns 0 when the @hwlock was successfully taken, and an appropriate | |
261 | * error code otherwise (most notably an -ETIMEDOUT if the @hwlock is still | |
262 | * busy after @timeout msecs). The function will never sleep. | |
263 | */ | |
264 | static inline | |
265 | int hwspin_lock_timeout(struct hwspinlock *hwlock, unsigned int to) | |
266 | { | |
267 | return __hwspin_lock_timeout(hwlock, to, 0, NULL); | |
268 | } | |
269 | ||
270 | /** | |
271 | * hwspin_unlock_irqrestore() - unlock hwspinlock, restore irq state | |
272 | * @hwlock: a previously-acquired hwspinlock which we want to unlock | |
273 | * @flags: previous caller's interrupt state to restore | |
274 | * | |
275 | * This function will unlock a specific hwspinlock, enable preemption and | |
276 | * restore the previous state of the local interrupts. It should be used | |
277 | * to undo, e.g., hwspin_trylock_irqsave(). | |
278 | * | |
279 | * @hwlock must be already locked before calling this function: it is a bug | |
280 | * to call unlock on a @hwlock that is already unlocked. | |
281 | */ | |
282 | static inline void hwspin_unlock_irqrestore(struct hwspinlock *hwlock, | |
283 | unsigned long *flags) | |
284 | { | |
285 | __hwspin_unlock(hwlock, HWLOCK_IRQSTATE, flags); | |
286 | } | |
287 | ||
288 | /** | |
289 | * hwspin_unlock_irq() - unlock hwspinlock, enable interrupts | |
290 | * @hwlock: a previously-acquired hwspinlock which we want to unlock | |
291 | * | |
292 | * This function will unlock a specific hwspinlock, enable preemption and | |
293 | * enable local interrupts. Should be used to undo hwspin_lock_irq(). | |
294 | * | |
295 | * @hwlock must be already locked (e.g. by hwspin_trylock_irq()) before | |
296 | * calling this function: it is a bug to call unlock on a @hwlock that is | |
297 | * already unlocked. | |
298 | */ | |
299 | static inline void hwspin_unlock_irq(struct hwspinlock *hwlock) | |
300 | { | |
301 | __hwspin_unlock(hwlock, HWLOCK_IRQ, NULL); | |
302 | } | |
303 | ||
304 | /** | |
305 | * hwspin_unlock() - unlock hwspinlock | |
306 | * @hwlock: a previously-acquired hwspinlock which we want to unlock | |
307 | * | |
308 | * This function will unlock a specific hwspinlock and enable preemption | |
309 | * back. | |
310 | * | |
311 | * @hwlock must be already locked (e.g. by hwspin_trylock()) before calling | |
312 | * this function: it is a bug to call unlock on a @hwlock that is already | |
313 | * unlocked. | |
314 | */ | |
315 | static inline void hwspin_unlock(struct hwspinlock *hwlock) | |
316 | { | |
317 | __hwspin_unlock(hwlock, 0, NULL); | |
318 | } | |
319 | ||
320 | #endif /* __LINUX_HWSPINLOCK_H */ |