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 int __intel_wakeref_get_first(struct intel_wakeref *wf) 14 { 15 intel_wakeref_t wakeref; 16 int ret = 0; 17 18 wakeref = intel_runtime_pm_get(&wf->i915->runtime_pm); 19 /* 20 * Treat get/put as different subclasses, as we may need to run 21 * the put callback from under the shrinker and do not want to 22 * cross-contanimate that callback with any extra work performed 23 * upon acquiring the wakeref. 24 */ 25 mutex_lock_nested(&wf->mutex, SINGLE_DEPTH_NESTING); 26 27 if (!atomic_read(&wf->count)) { 28 INTEL_WAKEREF_BUG_ON(wf->wakeref); 29 wf->wakeref = wakeref; 30 wakeref = 0; 31 32 ret = wf->ops->get(wf); 33 if (ret) { 34 wakeref = xchg(&wf->wakeref, 0); 35 wake_up_var(&wf->wakeref); 36 goto unlock; 37 } 38 39 smp_mb__before_atomic(); /* release wf->count */ 40 } 41 42 atomic_inc(&wf->count); 43 INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count) <= 0); 44 45 unlock: 46 mutex_unlock(&wf->mutex); 47 if (unlikely(wakeref)) 48 intel_runtime_pm_put(&wf->i915->runtime_pm, wakeref); 49 50 return ret; 51 } 52 53 static void ____intel_wakeref_put_last(struct intel_wakeref *wf) 54 { 55 intel_wakeref_t wakeref = 0; 56 57 INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count) <= 0); 58 if (unlikely(!atomic_dec_and_test(&wf->count))) 59 goto unlock; 60 61 /* ops->put() must reschedule its own release on error/deferral */ 62 if (likely(!wf->ops->put(wf))) { 63 INTEL_WAKEREF_BUG_ON(!wf->wakeref); 64 wakeref = xchg(&wf->wakeref, 0); 65 wake_up_var(&wf->wakeref); 66 } 67 68 unlock: 69 mutex_unlock(&wf->mutex); 70 if (wakeref) 71 intel_runtime_pm_put(&wf->i915->runtime_pm, wakeref); 72 } 73 74 void __intel_wakeref_put_last(struct intel_wakeref *wf, unsigned long flags) 75 { 76 INTEL_WAKEREF_BUG_ON(delayed_work_pending(&wf->work)); 77 78 /* Assume we are not in process context and so cannot sleep. */ 79 if (flags & INTEL_WAKEREF_PUT_ASYNC || !mutex_trylock(&wf->mutex)) { 80 mod_delayed_work(wf->i915->unordered_wq, &wf->work, 81 FIELD_GET(INTEL_WAKEREF_PUT_DELAY, flags)); 82 return; 83 } 84 85 ____intel_wakeref_put_last(wf); 86 } 87 88 static void __intel_wakeref_put_work(struct work_struct *wrk) 89 { 90 struct intel_wakeref *wf = container_of(wrk, typeof(*wf), work.work); 91 92 if (atomic_add_unless(&wf->count, -1, 1)) 93 return; 94 95 mutex_lock(&wf->mutex); 96 ____intel_wakeref_put_last(wf); 97 } 98 99 void __intel_wakeref_init(struct intel_wakeref *wf, 100 struct drm_i915_private *i915, 101 const struct intel_wakeref_ops *ops, 102 struct intel_wakeref_lockclass *key) 103 { 104 wf->i915 = i915; 105 wf->ops = ops; 106 107 __mutex_init(&wf->mutex, "wakeref.mutex", &key->mutex); 108 atomic_set(&wf->count, 0); 109 wf->wakeref = 0; 110 111 INIT_DELAYED_WORK(&wf->work, __intel_wakeref_put_work); 112 lockdep_init_map(&wf->work.work.lockdep_map, 113 "wakeref.work", &key->work, 0); 114 } 115 116 int intel_wakeref_wait_for_idle(struct intel_wakeref *wf) 117 { 118 int err; 119 120 might_sleep(); 121 122 err = wait_var_event_killable(&wf->wakeref, 123 !intel_wakeref_is_active(wf)); 124 if (err) 125 return err; 126 127 intel_wakeref_unlock_wait(wf); 128 return 0; 129 } 130 131 static void wakeref_auto_timeout(struct timer_list *t) 132 { 133 struct intel_wakeref_auto *wf = from_timer(wf, t, timer); 134 intel_wakeref_t wakeref; 135 unsigned long flags; 136 137 if (!refcount_dec_and_lock_irqsave(&wf->count, &wf->lock, &flags)) 138 return; 139 140 wakeref = fetch_and_zero(&wf->wakeref); 141 spin_unlock_irqrestore(&wf->lock, flags); 142 143 intel_runtime_pm_put(&wf->i915->runtime_pm, wakeref); 144 } 145 146 void intel_wakeref_auto_init(struct intel_wakeref_auto *wf, 147 struct drm_i915_private *i915) 148 { 149 spin_lock_init(&wf->lock); 150 timer_setup(&wf->timer, wakeref_auto_timeout, 0); 151 refcount_set(&wf->count, 0); 152 wf->wakeref = 0; 153 wf->i915 = i915; 154 } 155 156 void intel_wakeref_auto(struct intel_wakeref_auto *wf, unsigned long timeout) 157 { 158 unsigned long flags; 159 160 if (!timeout) { 161 if (del_timer_sync(&wf->timer)) 162 wakeref_auto_timeout(&wf->timer); 163 return; 164 } 165 166 /* Our mission is that we only extend an already active wakeref */ 167 assert_rpm_wakelock_held(&wf->i915->runtime_pm); 168 169 if (!refcount_inc_not_zero(&wf->count)) { 170 spin_lock_irqsave(&wf->lock, flags); 171 if (!refcount_inc_not_zero(&wf->count)) { 172 INTEL_WAKEREF_BUG_ON(wf->wakeref); 173 wf->wakeref = 174 intel_runtime_pm_get_if_in_use(&wf->i915->runtime_pm); 175 refcount_set(&wf->count, 1); 176 } 177 spin_unlock_irqrestore(&wf->lock, flags); 178 } 179 180 /* 181 * If we extend a pending timer, we will only get a single timer 182 * callback and so need to cancel the local inc by running the 183 * elided callback to keep the wf->count balanced. 184 */ 185 if (mod_timer(&wf->timer, jiffies + timeout)) 186 wakeref_auto_timeout(&wf->timer); 187 } 188 189 void intel_wakeref_auto_fini(struct intel_wakeref_auto *wf) 190 { 191 intel_wakeref_auto(wf, 0); 192 INTEL_WAKEREF_BUG_ON(wf->wakeref); 193 } 194