/*
 * Copyright (C) 2007 Ben Skeggs.
 * All Rights Reserved.
 *
 * 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 (including the
 * next paragraph) 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 OWNER(S) AND/OR ITS SUPPLIERS 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 <drm/drmP.h>

#include <linux/ktime.h>
#include <linux/hrtimer.h>

#include "nouveau_drm.h"
#include "nouveau_dma.h"
#include "nouveau_fence.h"

#include <engine/fifo.h>

void
nouveau_fence_context_del(struct nouveau_fence_chan *fctx)
{
        struct nouveau_fence *fence, *fnext;
        spin_lock(&fctx->lock);
        list_for_each_entry_safe(fence, fnext, &fctx->pending, head) {
                fence->channel = NULL;
                list_del(&fence->head);
                nouveau_fence_unref(&fence);
        }
        spin_unlock(&fctx->lock);
}

void
nouveau_fence_context_new(struct nouveau_fence_chan *fctx)
{
        INIT_LIST_HEAD(&fctx->flip);
        INIT_LIST_HEAD(&fctx->pending);
        spin_lock_init(&fctx->lock);
}

static void
nouveau_fence_update(struct nouveau_channel *chan)
{
        struct nouveau_fence_chan *fctx = chan->fence;
        struct nouveau_fence *fence, *fnext;

        spin_lock(&fctx->lock);
        list_for_each_entry_safe(fence, fnext, &fctx->pending, head) {
                if (fctx->read(chan) < fence->sequence)
                        break;

                fence->channel = NULL;
                list_del(&fence->head);
                nouveau_fence_unref(&fence);
        }
        spin_unlock(&fctx->lock);
}

int
nouveau_fence_emit(struct nouveau_fence *fence, struct nouveau_channel *chan)
{
        struct nouveau_fence_chan *fctx = chan->fence;
        int ret;

        fence->channel  = chan;
        fence->timeout  = jiffies + (3 * DRM_HZ);
        fence->sequence = ++fctx->sequence;

        ret = fctx->emit(fence);
        if (!ret) {
                kref_get(&fence->kref);
                spin_lock(&fctx->lock);
                list_add_tail(&fence->head, &fctx->pending);
                spin_unlock(&fctx->lock);
        }

        return ret;
}

bool
nouveau_fence_done(struct nouveau_fence *fence)
{
        if (fence->channel)
                nouveau_fence_update(fence->channel);
        return !fence->channel;
}

struct nouveau_fence_uevent {
        struct nouveau_eventh handler;
        struct nouveau_fence_priv *priv;
};

static int
nouveau_fence_wait_uevent_handler(struct nouveau_eventh *event, int index)
{
        struct nouveau_fence_uevent *uevent =
                container_of(event, struct nouveau_fence_uevent, handler);
        wake_up_all(&uevent->priv->waiting);
        return NVKM_EVENT_KEEP;
}

static int
nouveau_fence_wait_uevent(struct nouveau_fence *fence, bool intr)

{
        struct nouveau_channel *chan = fence->channel;
        struct nouveau_fifo *pfifo = nouveau_fifo(chan->drm->device);
        struct nouveau_fence_priv *priv = chan->drm->fence;
        struct nouveau_fence_uevent uevent = {
                .handler.func = nouveau_fence_wait_uevent_handler,
                .priv = priv,
        };
        int ret = 0;

        nouveau_event_get(pfifo->uevent, 0, &uevent.handler);

        if (fence->timeout) {
                unsigned long timeout = fence->timeout - jiffies;

                if (time_before(jiffies, fence->timeout)) {
                        if (intr) {
                                ret = wait_event_interruptible_timeout(
                                                priv->waiting,
                                                nouveau_fence_done(fence),
                                                timeout);
                        } else {
                                ret = wait_event_timeout(priv->waiting,
                                                nouveau_fence_done(fence),
                                                timeout);
                        }
                }

                if (ret >= 0) {
                        fence->timeout = jiffies + ret;
                        if (time_after_eq(jiffies, fence->timeout))
                                ret = -EBUSY;
                }
        } else {
                if (intr) {
                        ret = wait_event_interruptible(priv->waiting,
                                        nouveau_fence_done(fence));
                } else {
                        wait_event(priv->waiting, nouveau_fence_done(fence));
                }
        }

        nouveau_event_put(pfifo->uevent, 0, &uevent.handler);
        if (unlikely(ret < 0))
                return ret;

        return 0;
}

int
nouveau_fence_wait(struct nouveau_fence *fence, bool lazy, bool intr)
{
        struct nouveau_channel *chan = fence->channel;
        struct nouveau_fence_priv *priv = chan ? chan->drm->fence : NULL;
        unsigned long sleep_time = NSEC_PER_MSEC / 1000;
        ktime_t t;
        int ret = 0;

        while (priv && priv->uevent && lazy && !nouveau_fence_done(fence)) {
                ret = nouveau_fence_wait_uevent(fence, intr);
                if (ret < 0)
                        return ret;
        }

        while (!nouveau_fence_done(fence)) {
                if (fence->timeout && time_after_eq(jiffies, fence->timeout)) {
                        ret = -EBUSY;
                        break;
                }

                __set_current_state(intr ? TASK_INTERRUPTIBLE :
                                           TASK_UNINTERRUPTIBLE);
                if (lazy) {
                        t = ktime_set(0, sleep_time);
                        schedule_hrtimeout(&t, HRTIMER_MODE_REL);
                        sleep_time *= 2;
                        if (sleep_time > NSEC_PER_MSEC)
                                sleep_time = NSEC_PER_MSEC;
                }

                if (intr && signal_pending(current)) {
                        ret = -ERESTARTSYS;
                        break;
                }
        }

        __set_current_state(TASK_RUNNING);
        return ret;
}

int
nouveau_fence_sync(struct nouveau_fence *fence, struct nouveau_channel *chan)
{
        struct nouveau_fence_chan *fctx = chan->fence;
        struct nouveau_channel *prev;
        int ret = 0;

        prev = fence ? fence->channel : NULL;
        if (prev) {
                if (unlikely(prev != chan && !nouveau_fence_done(fence))) {
                        ret = fctx->sync(fence, prev, chan);
                        if (unlikely(ret))
                                ret = nouveau_fence_wait(fence, true, false);
                }
        }

        return ret;
}

static void
nouveau_fence_del(struct kref *kref)
{
        struct nouveau_fence *fence = container_of(kref, typeof(*fence), kref);
        kfree(fence);
}

void
nouveau_fence_unref(struct nouveau_fence **pfence)
{
        if (*pfence)
                kref_put(&(*pfence)->kref, nouveau_fence_del);
        *pfence = NULL;
}

struct nouveau_fence *
nouveau_fence_ref(struct nouveau_fence *fence)
{
        kref_get(&fence->kref);
        return fence;
}

int
nouveau_fence_new(struct nouveau_channel *chan, bool sysmem,
                  struct nouveau_fence **pfence)
{
        struct nouveau_fence *fence;
        int ret = 0;

        if (unlikely(!chan->fence))
                return -ENODEV;

        fence = kzalloc(sizeof(*fence), GFP_KERNEL);
        if (!fence)
                return -ENOMEM;

        fence->sysmem = sysmem;
        kref_init(&fence->kref);

        ret = nouveau_fence_emit(fence, chan);
        if (ret)
                nouveau_fence_unref(&fence);

        *pfence = fence;
        return ret;
}