1 /* 2 * SPDX-License-Identifier: MIT 3 * 4 * Copyright © 2019 Intel Corporation 5 */ 6 7 #ifndef INTEL_WAKEREF_H 8 #define INTEL_WAKEREF_H 9 10 #include <drm/drm_print.h> 11 12 #include <linux/atomic.h> 13 #include <linux/bitfield.h> 14 #include <linux/bits.h> 15 #include <linux/lockdep.h> 16 #include <linux/mutex.h> 17 #include <linux/refcount.h> 18 #include <linux/ref_tracker.h> 19 #include <linux/slab.h> 20 #include <linux/stackdepot.h> 21 #include <linux/timer.h> 22 #include <linux/workqueue.h> 23 24 typedef struct ref_tracker *intel_wakeref_t; 25 26 #define INTEL_REFTRACK_DEAD_COUNT 16 27 #define INTEL_REFTRACK_PRINT_LIMIT 16 28 29 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG) 30 #define INTEL_WAKEREF_BUG_ON(expr) BUG_ON(expr) 31 #else 32 #define INTEL_WAKEREF_BUG_ON(expr) BUILD_BUG_ON_INVALID(expr) 33 #endif 34 35 struct intel_runtime_pm; 36 struct intel_wakeref; 37 38 struct intel_wakeref_ops { 39 int (*get)(struct intel_wakeref *wf); 40 int (*put)(struct intel_wakeref *wf); 41 }; 42 43 struct intel_wakeref { 44 atomic_t count; 45 struct mutex mutex; 46 47 intel_wakeref_t wakeref; 48 49 struct drm_i915_private *i915; 50 const struct intel_wakeref_ops *ops; 51 52 struct delayed_work work; 53 54 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_WAKEREF) 55 struct ref_tracker_dir debug; 56 #endif 57 }; 58 59 struct intel_wakeref_lockclass { 60 struct lock_class_key mutex; 61 struct lock_class_key work; 62 }; 63 64 void __intel_wakeref_init(struct intel_wakeref *wf, 65 struct drm_i915_private *i915, 66 const struct intel_wakeref_ops *ops, 67 struct intel_wakeref_lockclass *key, 68 const char *name); 69 #define intel_wakeref_init(wf, i915, ops, name) do { \ 70 static struct intel_wakeref_lockclass __key; \ 71 \ 72 __intel_wakeref_init((wf), (i915), (ops), &__key, name); \ 73 } while (0) 74 75 int __intel_wakeref_get_first(struct intel_wakeref *wf); 76 void __intel_wakeref_put_last(struct intel_wakeref *wf, unsigned long flags); 77 78 /** 79 * intel_wakeref_get: Acquire the wakeref 80 * @wf: the wakeref 81 * 82 * Acquire a hold on the wakeref. The first user to do so, will acquire 83 * the runtime pm wakeref and then call the intel_wakeref_ops->get() 84 * underneath the wakeref mutex. 85 * 86 * Note that intel_wakeref_ops->get() is allowed to fail, in which case 87 * the runtime-pm wakeref will be released and the acquisition unwound, 88 * and an error reported. 89 * 90 * Returns: 0 if the wakeref was acquired successfully, or a negative error 91 * code otherwise. 92 */ 93 static inline int 94 intel_wakeref_get(struct intel_wakeref *wf) 95 { 96 might_sleep(); 97 if (unlikely(!atomic_inc_not_zero(&wf->count))) 98 return __intel_wakeref_get_first(wf); 99 100 return 0; 101 } 102 103 /** 104 * __intel_wakeref_get: Acquire the wakeref, again 105 * @wf: the wakeref 106 * 107 * Increment the wakeref counter, only valid if it is already held by 108 * the caller. 109 * 110 * See intel_wakeref_get(). 111 */ 112 static inline void 113 __intel_wakeref_get(struct intel_wakeref *wf) 114 { 115 INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count) <= 0); 116 atomic_inc(&wf->count); 117 } 118 119 /** 120 * intel_wakeref_get_if_active: Acquire the wakeref 121 * @wf: the wakeref 122 * 123 * Acquire a hold on the wakeref, but only if the wakeref is already 124 * active. 125 * 126 * Returns: true if the wakeref was acquired, false otherwise. 127 */ 128 static inline bool 129 intel_wakeref_get_if_active(struct intel_wakeref *wf) 130 { 131 return atomic_inc_not_zero(&wf->count); 132 } 133 134 enum { 135 INTEL_WAKEREF_PUT_ASYNC_BIT = 0, 136 __INTEL_WAKEREF_PUT_LAST_BIT__ 137 }; 138 139 static inline void 140 intel_wakeref_might_get(struct intel_wakeref *wf) 141 { 142 might_lock(&wf->mutex); 143 } 144 145 /** 146 * __intel_wakeref_put: Release the wakeref 147 * @wf: the wakeref 148 * @flags: control flags 149 * 150 * Release our hold on the wakeref. When there are no more users, 151 * the runtime pm wakeref will be released after the intel_wakeref_ops->put() 152 * callback is called underneath the wakeref mutex. 153 * 154 * Note that intel_wakeref_ops->put() is allowed to fail, in which case the 155 * runtime-pm wakeref is retained. 156 * 157 */ 158 static inline void 159 __intel_wakeref_put(struct intel_wakeref *wf, unsigned long flags) 160 #define INTEL_WAKEREF_PUT_ASYNC BIT(INTEL_WAKEREF_PUT_ASYNC_BIT) 161 #define INTEL_WAKEREF_PUT_DELAY \ 162 GENMASK(BITS_PER_LONG - 1, __INTEL_WAKEREF_PUT_LAST_BIT__) 163 { 164 INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count) <= 0); 165 if (unlikely(!atomic_add_unless(&wf->count, -1, 1))) 166 __intel_wakeref_put_last(wf, flags); 167 } 168 169 static inline void 170 intel_wakeref_put(struct intel_wakeref *wf) 171 { 172 might_sleep(); 173 __intel_wakeref_put(wf, 0); 174 } 175 176 static inline void 177 intel_wakeref_put_async(struct intel_wakeref *wf) 178 { 179 __intel_wakeref_put(wf, INTEL_WAKEREF_PUT_ASYNC); 180 } 181 182 static inline void 183 intel_wakeref_put_delay(struct intel_wakeref *wf, unsigned long delay) 184 { 185 __intel_wakeref_put(wf, 186 INTEL_WAKEREF_PUT_ASYNC | 187 FIELD_PREP(INTEL_WAKEREF_PUT_DELAY, delay)); 188 } 189 190 static inline void 191 intel_wakeref_might_put(struct intel_wakeref *wf) 192 { 193 might_lock(&wf->mutex); 194 } 195 196 /** 197 * intel_wakeref_lock: Lock the wakeref (mutex) 198 * @wf: the wakeref 199 * 200 * Locks the wakeref to prevent it being acquired or released. New users 201 * can still adjust the counter, but the wakeref itself (and callback) 202 * cannot be acquired or released. 203 */ 204 static inline void 205 intel_wakeref_lock(struct intel_wakeref *wf) 206 __acquires(wf->mutex) 207 { 208 mutex_lock(&wf->mutex); 209 } 210 211 /** 212 * intel_wakeref_unlock: Unlock the wakeref 213 * @wf: the wakeref 214 * 215 * Releases a previously acquired intel_wakeref_lock(). 216 */ 217 static inline void 218 intel_wakeref_unlock(struct intel_wakeref *wf) 219 __releases(wf->mutex) 220 { 221 mutex_unlock(&wf->mutex); 222 } 223 224 /** 225 * intel_wakeref_unlock_wait: Wait until the active callback is complete 226 * @wf: the wakeref 227 * 228 * Waits for the active callback (under the @wf->mutex or another CPU) is 229 * complete. 230 */ 231 static inline void 232 intel_wakeref_unlock_wait(struct intel_wakeref *wf) 233 { 234 mutex_lock(&wf->mutex); 235 mutex_unlock(&wf->mutex); 236 flush_delayed_work(&wf->work); 237 } 238 239 /** 240 * intel_wakeref_is_active: Query whether the wakeref is currently held 241 * @wf: the wakeref 242 * 243 * Returns: true if the wakeref is currently held. 244 */ 245 static inline bool 246 intel_wakeref_is_active(const struct intel_wakeref *wf) 247 { 248 return READ_ONCE(wf->wakeref); 249 } 250 251 /** 252 * __intel_wakeref_defer_park: Defer the current park callback 253 * @wf: the wakeref 254 */ 255 static inline void 256 __intel_wakeref_defer_park(struct intel_wakeref *wf) 257 { 258 lockdep_assert_held(&wf->mutex); 259 INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count)); 260 atomic_set_release(&wf->count, 1); 261 } 262 263 /** 264 * intel_wakeref_wait_for_idle: Wait until the wakeref is idle 265 * @wf: the wakeref 266 * 267 * Wait for the earlier asynchronous release of the wakeref. Note 268 * this will wait for any third party as well, so make sure you only wait 269 * when you have control over the wakeref and trust no one else is acquiring 270 * it. 271 * 272 * Return: 0 on success, error code if killed. 273 */ 274 int intel_wakeref_wait_for_idle(struct intel_wakeref *wf); 275 276 #define INTEL_WAKEREF_DEF ERR_PTR(-ENOENT) 277 278 static inline intel_wakeref_t intel_ref_tracker_alloc(struct ref_tracker_dir *dir) 279 { 280 struct ref_tracker *user = NULL; 281 282 ref_tracker_alloc(dir, &user, GFP_NOWAIT); 283 284 return user ?: INTEL_WAKEREF_DEF; 285 } 286 287 static inline void intel_ref_tracker_free(struct ref_tracker_dir *dir, 288 intel_wakeref_t wakeref) 289 { 290 if (wakeref == INTEL_WAKEREF_DEF) 291 wakeref = NULL; 292 293 if (WARN_ON(IS_ERR(wakeref))) 294 return; 295 296 ref_tracker_free(dir, &wakeref); 297 } 298 299 void intel_ref_tracker_show(struct ref_tracker_dir *dir, 300 struct drm_printer *p); 301 302 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_WAKEREF) 303 304 static inline intel_wakeref_t intel_wakeref_track(struct intel_wakeref *wf) 305 { 306 return intel_ref_tracker_alloc(&wf->debug); 307 } 308 309 static inline void intel_wakeref_untrack(struct intel_wakeref *wf, 310 intel_wakeref_t handle) 311 { 312 intel_ref_tracker_free(&wf->debug, handle); 313 } 314 315 #else 316 317 static inline intel_wakeref_t intel_wakeref_track(struct intel_wakeref *wf) 318 { 319 return INTEL_WAKEREF_DEF; 320 } 321 322 static inline void intel_wakeref_untrack(struct intel_wakeref *wf, 323 intel_wakeref_t handle) 324 { 325 } 326 327 #endif 328 329 struct intel_wakeref_auto { 330 struct drm_i915_private *i915; 331 struct timer_list timer; 332 intel_wakeref_t wakeref; 333 spinlock_t lock; 334 refcount_t count; 335 }; 336 337 /** 338 * intel_wakeref_auto: Delay the runtime-pm autosuspend 339 * @wf: the wakeref 340 * @timeout: relative timeout in jiffies 341 * 342 * The runtime-pm core uses a suspend delay after the last wakeref 343 * is released before triggering runtime suspend of the device. That 344 * delay is configurable via sysfs with little regard to the device 345 * characteristics. Instead, we want to tune the autosuspend based on our 346 * HW knowledge. intel_wakeref_auto() delays the sleep by the supplied 347 * timeout. 348 * 349 * Pass @timeout = 0 to cancel a previous autosuspend by executing the 350 * suspend immediately. 351 */ 352 void intel_wakeref_auto(struct intel_wakeref_auto *wf, unsigned long timeout); 353 354 void intel_wakeref_auto_init(struct intel_wakeref_auto *wf, 355 struct drm_i915_private *i915); 356 void intel_wakeref_auto_fini(struct intel_wakeref_auto *wf); 357 358 #endif /* INTEL_WAKEREF_H */ 359