1 /* 2 * SPDX-License-Identifier: MIT 3 * 4 * Copyright © 2019 Intel Corporation 5 */ 6 7 #include <linux/wait_bit.h> 8 9 #include "intel_runtime_pm.h" 10 #include "intel_wakeref.h" 11 #include "i915_drv.h" 12 13 static void rpm_get(struct intel_wakeref *wf) 14 { 15 wf->wakeref = intel_runtime_pm_get(&wf->i915->runtime_pm); 16 } 17 18 static void rpm_put(struct intel_wakeref *wf) 19 { 20 intel_wakeref_t wakeref = fetch_and_zero(&wf->wakeref); 21 22 intel_runtime_pm_put(&wf->i915->runtime_pm, wakeref); 23 INTEL_WAKEREF_BUG_ON(!wakeref); 24 } 25 26 int __intel_wakeref_get_first(struct intel_wakeref *wf) 27 { 28 /* 29 * Treat get/put as different subclasses, as we may need to run 30 * the put callback from under the shrinker and do not want to 31 * cross-contanimate that callback with any extra work performed 32 * upon acquiring the wakeref. 33 */ 34 mutex_lock_nested(&wf->mutex, SINGLE_DEPTH_NESTING); 35 if (!atomic_read(&wf->count)) { 36 int err; 37 38 rpm_get(wf); 39 40 err = wf->ops->get(wf); 41 if (unlikely(err)) { 42 rpm_put(wf); 43 mutex_unlock(&wf->mutex); 44 return err; 45 } 46 47 smp_mb__before_atomic(); /* release wf->count */ 48 } 49 atomic_inc(&wf->count); 50 mutex_unlock(&wf->mutex); 51 52 INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count) <= 0); 53 return 0; 54 } 55 56 static void ____intel_wakeref_put_last(struct intel_wakeref *wf) 57 { 58 INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count) <= 0); 59 if (unlikely(!atomic_dec_and_test(&wf->count))) 60 goto unlock; 61 62 /* ops->put() must reschedule its own release on error/deferral */ 63 if (likely(!wf->ops->put(wf))) { 64 rpm_put(wf); 65 wake_up_var(&wf->wakeref); 66 } 67 68 unlock: 69 mutex_unlock(&wf->mutex); 70 } 71 72 void __intel_wakeref_put_last(struct intel_wakeref *wf, unsigned long flags) 73 { 74 INTEL_WAKEREF_BUG_ON(delayed_work_pending(&wf->work)); 75 76 /* Assume we are not in process context and so cannot sleep. */ 77 if (flags & INTEL_WAKEREF_PUT_ASYNC || !mutex_trylock(&wf->mutex)) { 78 mod_delayed_work(wf->i915->unordered_wq, &wf->work, 79 FIELD_GET(INTEL_WAKEREF_PUT_DELAY, flags)); 80 return; 81 } 82 83 ____intel_wakeref_put_last(wf); 84 } 85 86 static void __intel_wakeref_put_work(struct work_struct *wrk) 87 { 88 struct intel_wakeref *wf = container_of(wrk, typeof(*wf), work.work); 89 90 if (atomic_add_unless(&wf->count, -1, 1)) 91 return; 92 93 mutex_lock(&wf->mutex); 94 ____intel_wakeref_put_last(wf); 95 } 96 97 void __intel_wakeref_init(struct intel_wakeref *wf, 98 struct drm_i915_private *i915, 99 const struct intel_wakeref_ops *ops, 100 struct intel_wakeref_lockclass *key) 101 { 102 wf->i915 = i915; 103 wf->ops = ops; 104 105 __mutex_init(&wf->mutex, "wakeref.mutex", &key->mutex); 106 atomic_set(&wf->count, 0); 107 wf->wakeref = 0; 108 109 INIT_DELAYED_WORK(&wf->work, __intel_wakeref_put_work); 110 lockdep_init_map(&wf->work.work.lockdep_map, 111 "wakeref.work", &key->work, 0); 112 } 113 114 int intel_wakeref_wait_for_idle(struct intel_wakeref *wf) 115 { 116 int err; 117 118 might_sleep(); 119 120 err = wait_var_event_killable(&wf->wakeref, 121 !intel_wakeref_is_active(wf)); 122 if (err) 123 return err; 124 125 intel_wakeref_unlock_wait(wf); 126 return 0; 127 } 128 129 static void wakeref_auto_timeout(struct timer_list *t) 130 { 131 struct intel_wakeref_auto *wf = from_timer(wf, t, timer); 132 intel_wakeref_t wakeref; 133 unsigned long flags; 134 135 if (!refcount_dec_and_lock_irqsave(&wf->count, &wf->lock, &flags)) 136 return; 137 138 wakeref = fetch_and_zero(&wf->wakeref); 139 spin_unlock_irqrestore(&wf->lock, flags); 140 141 intel_runtime_pm_put(&wf->i915->runtime_pm, wakeref); 142 } 143 144 void intel_wakeref_auto_init(struct intel_wakeref_auto *wf, 145 struct drm_i915_private *i915) 146 { 147 spin_lock_init(&wf->lock); 148 timer_setup(&wf->timer, wakeref_auto_timeout, 0); 149 refcount_set(&wf->count, 0); 150 wf->wakeref = 0; 151 wf->i915 = i915; 152 } 153 154 void intel_wakeref_auto(struct intel_wakeref_auto *wf, unsigned long timeout) 155 { 156 unsigned long flags; 157 158 if (!timeout) { 159 if (del_timer_sync(&wf->timer)) 160 wakeref_auto_timeout(&wf->timer); 161 return; 162 } 163 164 /* Our mission is that we only extend an already active wakeref */ 165 assert_rpm_wakelock_held(&wf->i915->runtime_pm); 166 167 if (!refcount_inc_not_zero(&wf->count)) { 168 spin_lock_irqsave(&wf->lock, flags); 169 if (!refcount_inc_not_zero(&wf->count)) { 170 INTEL_WAKEREF_BUG_ON(wf->wakeref); 171 wf->wakeref = 172 intel_runtime_pm_get_if_in_use(&wf->i915->runtime_pm); 173 refcount_set(&wf->count, 1); 174 } 175 spin_unlock_irqrestore(&wf->lock, flags); 176 } 177 178 /* 179 * If we extend a pending timer, we will only get a single timer 180 * callback and so need to cancel the local inc by running the 181 * elided callback to keep the wf->count balanced. 182 */ 183 if (mod_timer(&wf->timer, jiffies + timeout)) 184 wakeref_auto_timeout(&wf->timer); 185 } 186 187 void intel_wakeref_auto_fini(struct intel_wakeref_auto *wf) 188 { 189 intel_wakeref_auto(wf, 0); 190 INTEL_WAKEREF_BUG_ON(wf->wakeref); 191 } 192