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      1 /*	$NetBSD: nouveau_nvkm_core_notify.c,v 1.4 2021/12/18 23:45:34 riastradh Exp $	*/
      2 
      3 /*
      4  * Copyright 2014 Red Hat Inc.
      5  *
      6  * Permission is hereby granted, free of charge, to any person obtaining a
      7  * copy of this software and associated documentation files (the "Software"),
      8  * to deal in the Software without restriction, including without limitation
      9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
     10  * and/or sell copies of the Software, and to permit persons to whom the
     11  * Software is furnished to do so, subject to the following conditions:
     12  *
     13  * The above copyright notice and this permission notice shall be included in
     14  * all copies or substantial portions of the Software.
     15  *
     16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     19  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
     20  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
     21  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
     22  * OTHER DEALINGS IN THE SOFTWARE.
     23  *
     24  * Authors: Ben Skeggs <bskeggs (at) redhat.com>
     25  */
     26 #include <sys/cdefs.h>
     27 __KERNEL_RCSID(0, "$NetBSD: nouveau_nvkm_core_notify.c,v 1.4 2021/12/18 23:45:34 riastradh Exp $");
     28 
     29 #include <core/notify.h>
     30 #include <core/event.h>
     31 
     32 static inline void
     33 nvkm_notify_put_locked(struct nvkm_notify *notify)
     34 {
     35 	if (notify->block++ == 0)
     36 		nvkm_event_put(notify->event, notify->types, notify->index);
     37 }
     38 
     39 void
     40 nvkm_notify_put(struct nvkm_notify *notify)
     41 {
     42 	struct nvkm_event *event = notify->event;
     43 	unsigned long flags;
     44 	if (likely(event) &&
     45 	    test_and_clear_bit(NVKM_NOTIFY_USER, &notify->flags)) {
     46 		spin_lock_irqsave(&event->refs_lock, flags);
     47 		nvkm_notify_put_locked(notify);
     48 		spin_unlock_irqrestore(&event->refs_lock, flags);
     49 		if (test_bit(NVKM_NOTIFY_WORK, &notify->flags))
     50 			flush_work(&notify->work);
     51 	}
     52 }
     53 
     54 static inline void
     55 nvkm_notify_get_locked(struct nvkm_notify *notify)
     56 {
     57 	if (--notify->block == 0)
     58 		nvkm_event_get(notify->event, notify->types, notify->index);
     59 }
     60 
     61 void
     62 nvkm_notify_get(struct nvkm_notify *notify)
     63 {
     64 	struct nvkm_event *event = notify->event;
     65 	unsigned long flags;
     66 	if (likely(event) &&
     67 	    !test_and_set_bit(NVKM_NOTIFY_USER, &notify->flags)) {
     68 		spin_lock_irqsave(&event->refs_lock, flags);
     69 		nvkm_notify_get_locked(notify);
     70 		spin_unlock_irqrestore(&event->refs_lock, flags);
     71 	}
     72 }
     73 
     74 static inline void
     75 nvkm_notify_func(struct nvkm_notify *notify)
     76 {
     77 	struct nvkm_event *event = notify->event;
     78 	int ret = notify->func(notify);
     79 	unsigned long flags;
     80 	if ((ret == NVKM_NOTIFY_KEEP) ||
     81 	    !test_and_clear_bit(NVKM_NOTIFY_USER, &notify->flags)) {
     82 		spin_lock_irqsave(&event->refs_lock, flags);
     83 		nvkm_notify_get_locked(notify);
     84 		spin_unlock_irqrestore(&event->refs_lock, flags);
     85 	}
     86 }
     87 
     88 static void
     89 nvkm_notify_work(struct work_struct *work)
     90 {
     91 	struct nvkm_notify *notify = container_of(work, typeof(*notify), work);
     92 	nvkm_notify_func(notify);
     93 }
     94 
     95 void
     96 nvkm_notify_send(struct nvkm_notify *notify, void *data, u32 size)
     97 {
     98 	struct nvkm_event *event = notify->event;
     99 	unsigned long flags;
    100 
    101 	assert_spin_locked(&event->list_lock);
    102 	BUG_ON(size != notify->size);
    103 
    104 	spin_lock_irqsave(&event->refs_lock, flags);
    105 	if (notify->block) {
    106 		spin_unlock_irqrestore(&event->refs_lock, flags);
    107 		return;
    108 	}
    109 	nvkm_notify_put_locked(notify);
    110 	spin_unlock_irqrestore(&event->refs_lock, flags);
    111 
    112 	if (test_bit(NVKM_NOTIFY_WORK, &notify->flags)) {
    113 		memcpy(__UNCONST(notify->data), data, size);
    114 		schedule_work(&notify->work);
    115 	} else {
    116 		notify->data = data;
    117 		nvkm_notify_func(notify);
    118 		notify->data = NULL;
    119 	}
    120 }
    121 
    122 void
    123 nvkm_notify_fini(struct nvkm_notify *notify)
    124 {
    125 	unsigned long flags;
    126 	if (notify->event) {
    127 		nvkm_notify_put(notify);
    128 		spin_lock_irqsave(&notify->event->list_lock, flags);
    129 		list_del(&notify->head);
    130 		spin_unlock_irqrestore(&notify->event->list_lock, flags);
    131 		kfree(__UNCONST(notify->data));
    132 		notify->event = NULL;
    133 	}
    134 }
    135 
    136 int
    137 nvkm_notify_init(struct nvkm_object *object, struct nvkm_event *event,
    138 		 int (*func)(struct nvkm_notify *), bool work,
    139 		 void *data, u32 size, u32 reply,
    140 		 struct nvkm_notify *notify)
    141 {
    142 	unsigned long flags;
    143 	int ret = -ENODEV;
    144 	if ((notify->event = event), event->refs) {
    145 		ret = event->func->ctor(object, data, size, notify);
    146 		if (ret == 0 && (ret = -EINVAL, notify->size == reply)) {
    147 			notify->flags = 0;
    148 			notify->block = 1;
    149 			notify->func = func;
    150 			notify->data = NULL;
    151 			if (ret = 0, work) {
    152 				INIT_WORK(&notify->work, nvkm_notify_work);
    153 				set_bit(NVKM_NOTIFY_WORK, &notify->flags);
    154 				notify->data = kmalloc(reply, GFP_KERNEL);
    155 				if (!notify->data)
    156 					ret = -ENOMEM;
    157 			}
    158 		}
    159 		if (ret == 0) {
    160 			spin_lock_irqsave(&event->list_lock, flags);
    161 			list_add_tail(&notify->head, &event->list);
    162 			spin_unlock_irqrestore(&event->list_lock, flags);
    163 		}
    164 	}
    165 	if (ret)
    166 		notify->event = NULL;
    167 	return ret;
    168 }
    169