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 <linux/atomic.h> 11 #include <linux/bits.h> 12 #include <linux/mutex.h> 13 #include <linux/refcount.h> 14 #include <linux/stackdepot.h> 15 #include <linux/timer.h> 16 #include <linux/workqueue.h> 17 18 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG) 19 #define INTEL_WAKEREF_BUG_ON(expr) BUG_ON(expr) 20 #else 21 #define INTEL_WAKEREF_BUG_ON(expr) BUILD_BUG_ON_INVALID(expr) 22 #endif 23 24 struct intel_runtime_pm; 25 struct intel_wakeref; 26 27 typedef depot_stack_handle_t intel_wakeref_t; 28 29 struct intel_wakeref_ops { 30 int (*get)(struct intel_wakeref *wf); 31 int (*put)(struct intel_wakeref *wf); 32 33 unsigned long flags; 34 #define INTEL_WAKEREF_PUT_ASYNC BIT(0) 35 }; 36 37 struct intel_wakeref { 38 atomic_t count; 39 struct mutex mutex; 40 41 intel_wakeref_t wakeref; 42 43 struct intel_runtime_pm *rpm; 44 const struct intel_wakeref_ops *ops; 45 46 struct work_struct work; 47 }; 48 49 void __intel_wakeref_init(struct intel_wakeref *wf, 50 struct intel_runtime_pm *rpm, 51 const struct intel_wakeref_ops *ops, 52 struct lock_class_key *key); 53 #define intel_wakeref_init(wf, rpm, ops) do { \ 54 static struct lock_class_key __key; \ 55 \ 56 __intel_wakeref_init((wf), (rpm), (ops), &__key); \ 57 } while (0) 58 59 int __intel_wakeref_get_first(struct intel_wakeref *wf); 60 void __intel_wakeref_put_last(struct intel_wakeref *wf); 61 62 /** 63 * intel_wakeref_get: Acquire the wakeref 64 * @i915: the drm_i915_private device 65 * @wf: the wakeref 66 * @fn: callback for acquired the wakeref, called only on first acquire. 67 * 68 * Acquire a hold on the wakeref. The first user to do so, will acquire 69 * the runtime pm wakeref and then call the @fn underneath the wakeref 70 * mutex. 71 * 72 * Note that @fn is allowed to fail, in which case the runtime-pm wakeref 73 * will be released and the acquisition unwound, and an error reported. 74 * 75 * Returns: 0 if the wakeref was acquired successfully, or a negative error 76 * code otherwise. 77 */ 78 static inline int 79 intel_wakeref_get(struct intel_wakeref *wf) 80 { 81 if (unlikely(!atomic_inc_not_zero(&wf->count))) 82 return __intel_wakeref_get_first(wf); 83 84 return 0; 85 } 86 87 /** 88 * intel_wakeref_get_if_in_use: Acquire the wakeref 89 * @wf: the wakeref 90 * 91 * Acquire a hold on the wakeref, but only if the wakeref is already 92 * active. 93 * 94 * Returns: true if the wakeref was acquired, false otherwise. 95 */ 96 static inline bool 97 intel_wakeref_get_if_active(struct intel_wakeref *wf) 98 { 99 return atomic_inc_not_zero(&wf->count); 100 } 101 102 /** 103 * intel_wakeref_put: Release the wakeref 104 * @i915: the drm_i915_private device 105 * @wf: the wakeref 106 * @fn: callback for releasing the wakeref, called only on final release. 107 * 108 * Release our hold on the wakeref. When there are no more users, 109 * the runtime pm wakeref will be released after the @fn callback is called 110 * underneath the wakeref mutex. 111 * 112 * Note that @fn is allowed to fail, in which case the runtime-pm wakeref 113 * is retained and an error reported. 114 * 115 * Returns: 0 if the wakeref was released successfully, or a negative error 116 * code otherwise. 117 */ 118 static inline void 119 intel_wakeref_put(struct intel_wakeref *wf) 120 { 121 INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count) <= 0); 122 if (unlikely(!atomic_add_unless(&wf->count, -1, 1))) 123 __intel_wakeref_put_last(wf); 124 } 125 126 /** 127 * intel_wakeref_lock: Lock the wakeref (mutex) 128 * @wf: the wakeref 129 * 130 * Locks the wakeref to prevent it being acquired or released. New users 131 * can still adjust the counter, but the wakeref itself (and callback) 132 * cannot be acquired or released. 133 */ 134 static inline void 135 intel_wakeref_lock(struct intel_wakeref *wf) 136 __acquires(wf->mutex) 137 { 138 mutex_lock(&wf->mutex); 139 } 140 141 /** 142 * intel_wakeref_unlock: Unlock the wakeref 143 * @wf: the wakeref 144 * 145 * Releases a previously acquired intel_wakeref_lock(). 146 */ 147 static inline void 148 intel_wakeref_unlock(struct intel_wakeref *wf) 149 __releases(wf->mutex) 150 { 151 mutex_unlock(&wf->mutex); 152 } 153 154 /** 155 * intel_wakeref_is_active: Query whether the wakeref is currently held 156 * @wf: the wakeref 157 * 158 * Returns: true if the wakeref is currently held. 159 */ 160 static inline bool 161 intel_wakeref_is_active(const struct intel_wakeref *wf) 162 { 163 return READ_ONCE(wf->wakeref); 164 } 165 166 /** 167 * __intel_wakeref_defer_park: Defer the current park callback 168 * @wf: the wakeref 169 */ 170 static inline void 171 __intel_wakeref_defer_park(struct intel_wakeref *wf) 172 { 173 INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count)); 174 atomic_set_release(&wf->count, 1); 175 } 176 177 /** 178 * intel_wakeref_wait_for_idle: Wait until the wakeref is idle 179 * @wf: the wakeref 180 * 181 * Wait for the earlier asynchronous release of the wakeref. Note 182 * this will wait for any third party as well, so make sure you only wait 183 * when you have control over the wakeref and trust no one else is acquiring 184 * it. 185 * 186 * Return: 0 on success, error code if killed. 187 */ 188 int intel_wakeref_wait_for_idle(struct intel_wakeref *wf); 189 190 struct intel_wakeref_auto { 191 struct intel_runtime_pm *rpm; 192 struct timer_list timer; 193 intel_wakeref_t wakeref; 194 spinlock_t lock; 195 refcount_t count; 196 }; 197 198 /** 199 * intel_wakeref_auto: Delay the runtime-pm autosuspend 200 * @wf: the wakeref 201 * @timeout: relative timeout in jiffies 202 * 203 * The runtime-pm core uses a suspend delay after the last wakeref 204 * is released before triggering runtime suspend of the device. That 205 * delay is configurable via sysfs with little regard to the device 206 * characteristics. Instead, we want to tune the autosuspend based on our 207 * HW knowledge. intel_wakeref_auto() delays the sleep by the supplied 208 * timeout. 209 * 210 * Pass @timeout = 0 to cancel a previous autosuspend by executing the 211 * suspend immediately. 212 */ 213 void intel_wakeref_auto(struct intel_wakeref_auto *wf, unsigned long timeout); 214 215 void intel_wakeref_auto_init(struct intel_wakeref_auto *wf, 216 struct intel_runtime_pm *rpm); 217 void intel_wakeref_auto_fini(struct intel_wakeref_auto *wf); 218 219 #endif /* INTEL_WAKEREF_H */ 220