/*
 * Copyright 2013-2014 Red Hat Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */
#include <core/event.h>
#include <core/subdev.h>

static void
nvkm_event_put(struct nvkm_event *event, u32 types, int index)
{
	assert_spin_locked(&event->refs_lock);

	nvkm_trace(event->subdev, "event: decr %08x on %d\n", types, index);

	while (types) {
		int type = __ffs(types); types &= ~(1 << type);
		if (--event->refs[index * event->types_nr + type] == 0) {
			nvkm_trace(event->subdev, "event: blocking %d on %d\n", type, index);
			if (event->func->fini)
				event->func->fini(event, 1 << type, index);
		}
	}
}

static void
nvkm_event_get(struct nvkm_event *event, u32 types, int index)
{
	assert_spin_locked(&event->refs_lock);

	nvkm_trace(event->subdev, "event: incr %08x on %d\n", types, index);

	while (types) {
		int type = __ffs(types); types &= ~(1 << type);
		if (++event->refs[index * event->types_nr + type] == 1) {
			nvkm_trace(event->subdev, "event: allowing %d on %d\n", type, index);
			if (event->func->init)
				event->func->init(event, 1 << type, index);
		}
	}
}

static void
nvkm_event_ntfy_state(struct nvkm_event_ntfy *ntfy)
{
	struct nvkm_event *event = ntfy->event;
	unsigned long flags;

	nvkm_trace(event->subdev, "event: ntfy state changed\n");
	spin_lock_irqsave(&event->refs_lock, flags);

	if (atomic_read(&ntfy->allowed) != ntfy->running) {
		if (ntfy->running) {
			nvkm_event_put(ntfy->event, ntfy->bits, ntfy->id);
			ntfy->running = false;
		} else {
			nvkm_event_get(ntfy->event, ntfy->bits, ntfy->id);
			ntfy->running = true;
		}
	}

	spin_unlock_irqrestore(&event->refs_lock, flags);
}

static void
nvkm_event_ntfy_remove(struct nvkm_event_ntfy *ntfy)
{
	write_lock_irq(&ntfy->event->list_lock);
	list_del_init(&ntfy->head);
	write_unlock_irq(&ntfy->event->list_lock);
}

static void
nvkm_event_ntfy_insert(struct nvkm_event_ntfy *ntfy)
{
	write_lock_irq(&ntfy->event->list_lock);
	list_add_tail(&ntfy->head, &ntfy->event->ntfy);
	write_unlock_irq(&ntfy->event->list_lock);
}

static void
nvkm_event_ntfy_block_(struct nvkm_event_ntfy *ntfy, bool wait)
{
	struct nvkm_subdev *subdev = ntfy->event->subdev;

	nvkm_trace(subdev, "event: ntfy block %08x on %d wait:%d\n", ntfy->bits, ntfy->id, wait);

	if (atomic_xchg(&ntfy->allowed, 0) == 1) {
		nvkm_event_ntfy_state(ntfy);
		if (wait)
			nvkm_event_ntfy_remove(ntfy);
	}
}

void
nvkm_event_ntfy_block(struct nvkm_event_ntfy *ntfy)
{
	if (ntfy->event)
		nvkm_event_ntfy_block_(ntfy, ntfy->wait);
}

void
nvkm_event_ntfy_allow(struct nvkm_event_ntfy *ntfy)
{
	nvkm_trace(ntfy->event->subdev, "event: ntfy allow %08x on %d\n", ntfy->bits, ntfy->id);

	if (atomic_xchg(&ntfy->allowed, 1) == 0) {
		nvkm_event_ntfy_state(ntfy);
		if (ntfy->wait)
			nvkm_event_ntfy_insert(ntfy);
	}
}

void
nvkm_event_ntfy_del(struct nvkm_event_ntfy *ntfy)
{
	struct nvkm_event *event = ntfy->event;

	if (!event)
		return;

	nvkm_trace(event->subdev, "event: ntfy del %08x on %d\n", ntfy->bits, ntfy->id);

	nvkm_event_ntfy_block_(ntfy, false);
	nvkm_event_ntfy_remove(ntfy);
	ntfy->event = NULL;
}

void
nvkm_event_ntfy_add(struct nvkm_event *event, int id, u32 bits, bool wait, nvkm_event_func func,
		    struct nvkm_event_ntfy *ntfy)
{
	nvkm_trace(event->subdev, "event: ntfy add %08x on %d wait:%d\n", id, bits, wait);

	ntfy->event = event;
	ntfy->id = id;
	ntfy->bits = bits;
	ntfy->wait = wait;
	ntfy->func = func;
	atomic_set(&ntfy->allowed, 0);
	ntfy->running = false;
	INIT_LIST_HEAD(&ntfy->head);
	if (!ntfy->wait)
		nvkm_event_ntfy_insert(ntfy);
}

bool
nvkm_event_ntfy_valid(struct nvkm_event *event, int id, u32 bits)
{
	return true;
}

void
nvkm_event_ntfy(struct nvkm_event *event, int id, u32 bits)
{
	struct nvkm_event_ntfy *ntfy, *ntmp;
	unsigned long flags;

	if (!event->refs || WARN_ON(id >= event->index_nr))
		return;

	nvkm_trace(event->subdev, "event: ntfy %08x on %d\n", bits, id);
	read_lock_irqsave(&event->list_lock, flags);

	list_for_each_entry_safe(ntfy, ntmp, &event->ntfy, head) {
		if (ntfy->id == id && ntfy->bits & bits) {
			if (atomic_read(&ntfy->allowed))
				ntfy->func(ntfy, ntfy->bits & bits);
		}
	}

	read_unlock_irqrestore(&event->list_lock, flags);
}

void
nvkm_event_fini(struct nvkm_event *event)
{
	if (event->refs) {
		kfree(event->refs);
		event->refs = NULL;
	}
}

int
__nvkm_event_init(const struct nvkm_event_func *func, struct nvkm_subdev *subdev,
		  int types_nr, int index_nr, struct nvkm_event *event)
{
	event->refs = kzalloc(array3_size(index_nr, types_nr, sizeof(*event->refs)), GFP_KERNEL);
	if (!event->refs)
		return -ENOMEM;

	event->func = func;
	event->subdev = subdev;
	event->types_nr = types_nr;
	event->index_nr = index_nr;
	INIT_LIST_HEAD(&event->ntfy);
	return 0;
}