1 /* $NetBSD: intel_wakeref.h,v 1.4 2021/12/19 12:33:57 riastradh Exp $ */ 2 3 /* 4 * SPDX-License-Identifier: MIT 5 * 6 * Copyright 2019 Intel Corporation 7 */ 8 9 #ifndef INTEL_WAKEREF_H 10 #define INTEL_WAKEREF_H 11 12 #include <linux/atomic.h> 13 #include <linux/bits.h> 14 #include <linux/lockdep.h> 15 #include <linux/mutex.h> 16 #include <linux/refcount.h> 17 #include <linux/stackdepot.h> 18 #include <linux/timer.h> 19 #include <linux/workqueue.h> 20 21 #include <drm/drm_wait_netbsd.h> /* XXX */ 22 23 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG) 24 #define INTEL_WAKEREF_BUG_ON(expr) BUG_ON(expr) 25 #else 26 #define INTEL_WAKEREF_BUG_ON(expr) BUILD_BUG_ON_INVALID(expr) 27 #endif 28 29 struct intel_runtime_pm; 30 struct intel_wakeref; 31 32 typedef depot_stack_handle_t intel_wakeref_t; 33 34 struct intel_wakeref_ops { 35 int (*get)(struct intel_wakeref *wf); 36 int (*put)(struct intel_wakeref *wf); 37 }; 38 39 struct intel_wakeref { 40 atomic_t count; 41 struct mutex mutex; 42 43 intel_wakeref_t wakeref; 44 drm_waitqueue_t wq; 45 46 struct intel_runtime_pm *rpm; 47 const struct intel_wakeref_ops *ops; 48 49 struct work_struct work; 50 }; 51 52 struct intel_wakeref_lockclass { 53 struct lock_class_key mutex; 54 struct lock_class_key work; 55 }; 56 57 void __intel_wakeref_init(struct intel_wakeref *wf, 58 struct intel_runtime_pm *rpm, 59 const struct intel_wakeref_ops *ops, 60 struct intel_wakeref_lockclass *key); 61 #define intel_wakeref_init(wf, rpm, ops) do { \ 62 static struct intel_wakeref_lockclass __key; \ 63 \ 64 __intel_wakeref_init((wf), (rpm), (ops), &__key); \ 65 } while (0) 66 67 void intel_wakeref_fini(struct intel_wakeref *); 68 69 int __intel_wakeref_get_first(struct intel_wakeref *wf); 70 void __intel_wakeref_put_last(struct intel_wakeref *wf, unsigned long flags); 71 72 /** 73 * intel_wakeref_get: Acquire the wakeref 74 * @wf: the wakeref 75 * 76 * Acquire a hold on the wakeref. The first user to do so, will acquire 77 * the runtime pm wakeref and then call the @fn underneath the wakeref 78 * mutex. 79 * 80 * Note that @fn is allowed to fail, in which case the runtime-pm wakeref 81 * will be released and the acquisition unwound, and an error reported. 82 * 83 * Returns: 0 if the wakeref was acquired successfully, or a negative error 84 * code otherwise. 85 */ 86 static inline int 87 intel_wakeref_get(struct intel_wakeref *wf) 88 { 89 might_sleep(); 90 if (unlikely(!atomic_inc_not_zero(&wf->count))) 91 return __intel_wakeref_get_first(wf); 92 93 return 0; 94 } 95 96 /** 97 * __intel_wakeref_get: Acquire the wakeref, again 98 * @wf: the wakeref 99 * 100 * Increment the wakeref counter, only valid if it is already held by 101 * the caller. 102 * 103 * See intel_wakeref_get(). 104 */ 105 static inline void 106 __intel_wakeref_get(struct intel_wakeref *wf) 107 { 108 INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count) <= 0); 109 atomic_inc(&wf->count); 110 } 111 112 /** 113 * intel_wakeref_get_if_in_use: Acquire the wakeref 114 * @wf: the wakeref 115 * 116 * Acquire a hold on the wakeref, but only if the wakeref is already 117 * active. 118 * 119 * Returns: true if the wakeref was acquired, false otherwise. 120 */ 121 static inline bool 122 intel_wakeref_get_if_active(struct intel_wakeref *wf) 123 { 124 return atomic_inc_not_zero(&wf->count); 125 } 126 127 /** 128 * intel_wakeref_put_flags: Release the wakeref 129 * @wf: the wakeref 130 * @flags: control flags 131 * 132 * Release our hold on the wakeref. When there are no more users, 133 * the runtime pm wakeref will be released after the @fn callback is called 134 * underneath the wakeref mutex. 135 * 136 * Note that @fn is allowed to fail, in which case the runtime-pm wakeref 137 * is retained and an error reported. 138 * 139 * Returns: 0 if the wakeref was released successfully, or a negative error 140 * code otherwise. 141 */ 142 static inline void 143 __intel_wakeref_put(struct intel_wakeref *wf, unsigned long flags) 144 #define INTEL_WAKEREF_PUT_ASYNC BIT(0) 145 { 146 INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count) <= 0); 147 if (unlikely(!atomic_add_unless(&wf->count, -1, 1))) 148 __intel_wakeref_put_last(wf, flags); 149 } 150 151 static inline void 152 intel_wakeref_put(struct intel_wakeref *wf) 153 { 154 might_sleep(); 155 __intel_wakeref_put(wf, 0); 156 } 157 158 static inline void 159 intel_wakeref_put_async(struct intel_wakeref *wf) 160 { 161 __intel_wakeref_put(wf, INTEL_WAKEREF_PUT_ASYNC); 162 } 163 164 /** 165 * intel_wakeref_lock: Lock the wakeref (mutex) 166 * @wf: the wakeref 167 * 168 * Locks the wakeref to prevent it being acquired or released. New users 169 * can still adjust the counter, but the wakeref itself (and callback) 170 * cannot be acquired or released. 171 */ 172 static inline void 173 intel_wakeref_lock(struct intel_wakeref *wf) 174 __acquires(wf->mutex) 175 { 176 mutex_lock(&wf->mutex); 177 } 178 179 /** 180 * intel_wakeref_unlock: Unlock the wakeref 181 * @wf: the wakeref 182 * 183 * Releases a previously acquired intel_wakeref_lock(). 184 */ 185 static inline void 186 intel_wakeref_unlock(struct intel_wakeref *wf) 187 __releases(wf->mutex) 188 { 189 mutex_unlock(&wf->mutex); 190 } 191 192 /** 193 * intel_wakeref_unlock_wait: Wait until the active callback is complete 194 * @wf: the wakeref 195 * 196 * Waits for the active callback (under the @wf->mutex or another CPU) is 197 * complete. 198 */ 199 static inline void 200 intel_wakeref_unlock_wait(struct intel_wakeref *wf) 201 { 202 mutex_lock(&wf->mutex); 203 mutex_unlock(&wf->mutex); 204 flush_work(&wf->work); 205 } 206 207 /** 208 * intel_wakeref_is_active: Query whether the wakeref is currently held 209 * @wf: the wakeref 210 * 211 * Returns: true if the wakeref is currently held. 212 */ 213 static inline bool 214 intel_wakeref_is_active(const struct intel_wakeref *wf) 215 { 216 return READ_ONCE(wf->wakeref); 217 } 218 219 /** 220 * __intel_wakeref_defer_park: Defer the current park callback 221 * @wf: the wakeref 222 */ 223 static inline void 224 __intel_wakeref_defer_park(struct intel_wakeref *wf) 225 { 226 lockdep_assert_held(&wf->mutex); 227 INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count)); 228 atomic_set_release(&wf->count, 1); 229 } 230 231 /** 232 * intel_wakeref_wait_for_idle: Wait until the wakeref is idle 233 * @wf: the wakeref 234 * 235 * Wait for the earlier asynchronous release of the wakeref. Note 236 * this will wait for any third party as well, so make sure you only wait 237 * when you have control over the wakeref and trust no one else is acquiring 238 * it. 239 * 240 * Return: 0 on success, error code if killed. 241 */ 242 int intel_wakeref_wait_for_idle(struct intel_wakeref *wf); 243 244 struct intel_wakeref_auto { 245 struct intel_runtime_pm *rpm; 246 struct timer_list timer; 247 intel_wakeref_t wakeref; 248 spinlock_t lock; 249 refcount_t count; 250 }; 251 252 /** 253 * intel_wakeref_auto: Delay the runtime-pm autosuspend 254 * @wf: the wakeref 255 * @timeout: relative timeout in jiffies 256 * 257 * The runtime-pm core uses a suspend delay after the last wakeref 258 * is released before triggering runtime suspend of the device. That 259 * delay is configurable via sysfs with little regard to the device 260 * characteristics. Instead, we want to tune the autosuspend based on our 261 * HW knowledge. intel_wakeref_auto() delays the sleep by the supplied 262 * timeout. 263 * 264 * Pass @timeout = 0 to cancel a previous autosuspend by executing the 265 * suspend immediately. 266 */ 267 void intel_wakeref_auto(struct intel_wakeref_auto *wf, unsigned long timeout); 268 269 void intel_wakeref_auto_init(struct intel_wakeref_auto *wf, 270 struct intel_runtime_pm *rpm); 271 void intel_wakeref_auto_fini(struct intel_wakeref_auto *wf); 272 273 #endif /* INTEL_WAKEREF_H */ 274
Indexes created Sun Sep 21 14:09:52 GMT 2025