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 #ifdef __linux__ 108 __mutex_init(&wf->mutex, "wakeref.mutex", &key->mutex); 109 #else 110 rw_init(&wf->mutex, "wakeref.mutex"); 111 #endif 112 atomic_set(&wf->count, 0); 113 wf->wakeref = 0; 114 115 INIT_DELAYED_WORK(&wf->work, __intel_wakeref_put_work); 116 lockdep_init_map(&wf->work.work.lockdep_map, 117 "wakeref.work", &key->work, 0); 118 } 119 120 int intel_wakeref_wait_for_idle(struct intel_wakeref *wf) 121 { 122 int err; 123 124 might_sleep(); 125 126 err = wait_var_event_killable(&wf->wakeref, 127 !intel_wakeref_is_active(wf)); 128 if (err) 129 return err; 130 131 intel_wakeref_unlock_wait(wf); 132 return 0; 133 } 134 135 static void wakeref_auto_timeout(void *arg) 136 { 137 struct intel_wakeref_auto *wf = arg; 138 intel_wakeref_t wakeref; 139 unsigned long flags; 140 141 if (!refcount_dec_and_lock_irqsave(&wf->count, &wf->lock, &flags)) 142 return; 143 144 wakeref = fetch_and_zero(&wf->wakeref); 145 spin_unlock_irqrestore(&wf->lock, flags); 146 147 intel_runtime_pm_put(&wf->i915->runtime_pm, wakeref); 148 } 149 150 void intel_wakeref_auto_init(struct intel_wakeref_auto *wf, 151 struct drm_i915_private *i915) 152 { 153 mtx_init(&wf->lock, IPL_TTY); 154 #ifdef __linux__ 155 timer_setup(&wf->timer, wakeref_auto_timeout, 0); 156 #else 157 timeout_set(&wf->timer, wakeref_auto_timeout, wf); 158 #endif 159 refcount_set(&wf->count, 0); 160 wf->wakeref = 0; 161 wf->i915 = i915; 162 } 163 164 void intel_wakeref_auto(struct intel_wakeref_auto *wf, unsigned long timeout) 165 { 166 unsigned long flags; 167 168 if (!timeout) { 169 if (del_timer_sync(&wf->timer)) 170 wakeref_auto_timeout(&wf->timer); 171 return; 172 } 173 174 /* Our mission is that we only extend an already active wakeref */ 175 assert_rpm_wakelock_held(&wf->i915->runtime_pm); 176 177 if (!refcount_inc_not_zero(&wf->count)) { 178 spin_lock_irqsave(&wf->lock, flags); 179 if (!refcount_inc_not_zero(&wf->count)) { 180 INTEL_WAKEREF_BUG_ON(wf->wakeref); 181 wf->wakeref = 182 intel_runtime_pm_get_if_in_use(&wf->i915->runtime_pm); 183 refcount_set(&wf->count, 1); 184 } 185 spin_unlock_irqrestore(&wf->lock, flags); 186 } 187 188 /* 189 * If we extend a pending timer, we will only get a single timer 190 * callback and so need to cancel the local inc by running the 191 * elided callback to keep the wf->count balanced. 192 */ 193 if (mod_timer(&wf->timer, jiffies + timeout)) 194 wakeref_auto_timeout(&wf->timer); 195 } 196 197 void intel_wakeref_auto_fini(struct intel_wakeref_auto *wf) 198 { 199 intel_wakeref_auto(wf, 0); 200 INTEL_WAKEREF_BUG_ON(wf->wakeref); 201 } 202