/**************************************************************************
 * 
 * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND., USA
 * 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, sub license, 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 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 NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE COPYRIGHT HOLDERS, AUTHORS 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.
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 * 
 * 
 **************************************************************************/
/*
 * Authors: Thomas Hellström <thomas-at-tungstengraphics-dot-com>
 */

#include "drmP.h"

static void drm_fm_update_pointers(drm_fence_manager_t * fm,
				   struct list_head *list, int no_types,
				   uint32_t type)
{
	int i;
	for (i = 0; i < no_types; ++i) {
		if (type & (1 << i)) {
			fm->fence_types[i] = list;
		}
	}
}

/*
 * Typically called by the IRQ handler.
 */

void drm_fence_handler(drm_device_t * dev, uint32_t sequence, uint32_t type)
{
	int i;
	int wake = 0;
	int largest = 0;
	uint32_t diff;
	uint32_t relevant;
	int index = 0;
	drm_fence_manager_t *fm = &dev->fm;
	drm_fence_driver_t *driver = dev->driver->fence_driver;
	struct list_head *list;
	struct list_head *fence_list;
	drm_fence_object_t *fence;
	int found = 0;

	for (i = 0; i < driver->no_types; ++i) {
		if (!(type & (1 << i)))
			continue;

		list = fm->fence_types[i];
		fence_list = list->next;

		if (fence_list == &fm->ring)
			continue;

		fence = list_entry(fence_list, drm_fence_object_t, ring);

		diff = (sequence - fence->sequence) & driver->sequence_mask;

		if (diff < driver->wrap_diff) {
			if (diff >= largest) {
				largest = diff;
				index = i;
				found = 1;
			}
		}
	}

	if (!found)
		return;

	/*
	 * Start with the fence object with the lowest sequence number, affected by
	 * the type mask of this call. Update signaled fields, 
	 * Check if we need to wake sleeping processes
	 */

	list = fm->fence_types[index]->next;
	do {
		if (list == &fm->ring) {
			drm_fm_update_pointers(fm, list->prev,
					       driver->no_types, type);
			break;
		}
		fence = list_entry(list, drm_fence_object_t, ring);
		diff = (sequence - fence->sequence) & driver->sequence_mask;
		if (diff >= driver->wrap_diff) {
			drm_fm_update_pointers(fm, fence->ring.prev,
					       driver->no_types, type);
			break;
		}
		relevant = type & fence->type;
		if ((fence->signaled | relevant) != fence->signaled) {
			fence->signaled |= relevant;
			fence->submitted_flush |= relevant;
			wake = 1;
		}

		relevant = fence->flush_mask &
		    ~(fence->signaled | fence->submitted_flush);
		if (relevant) {
			fm->pending_flush |= relevant;
			fence->submitted_flush = fence->flush_mask;
		}

		list = list->next;

		/*
		 * Remove a completely signaled fence from the
		 * fence manager ring.
		 */

		if (!(fence->type & ~fence->signaled)) {
			fence_list = &fence->ring;
			for (i = 0; i < driver->no_types; ++i) {
				if (fm->fence_types[i] == fence_list)
					fm->fence_types[i] = fence_list->prev;
			}
			list_del_init(fence_list);
		}

	} while (1);

	/*
	 * Wake sleeping processes.
	 */

	if (wake) {
		DRM_WAKEUP(&fm->fence_queue);
	}
}

EXPORT_SYMBOL(drm_fence_handler);

static void drm_fence_unring(drm_device_t * dev, struct list_head *ring)
{
	drm_fence_manager_t *fm = &dev->fm;
	drm_fence_driver_t *driver = dev->driver->fence_driver;
	unsigned long flags;
	int i;

	write_lock_irqsave(&fm->lock, flags);
	for (i = 0; i < driver->no_types; ++i) {
		if (fm->fence_types[i] == ring)
			fm->fence_types[i] = ring->prev;
	}
	list_del_init(ring);
	write_unlock_irqrestore(&fm->lock, flags);
}

void drm_fence_usage_deref_locked(drm_device_t * dev,
				  drm_fence_object_t * fence)
{
	if (atomic_dec_and_test(&fence->usage)) {
		drm_fence_unring(dev, &fence->ring);
		drm_free(fence, sizeof(*fence), DRM_MEM_FENCE);
	}
}

void drm_fence_usage_deref_unlocked(drm_device_t * dev,
				    drm_fence_object_t * fence)
{
	if (atomic_dec_and_test(&fence->usage)) {
		mutex_lock(&dev->struct_mutex);
		if (atomic_read(&fence->usage) == 0) {
			drm_fence_unring(dev, &fence->ring);
			drm_free(fence, sizeof(*fence), DRM_MEM_FENCE);
		}
		mutex_unlock(&dev->struct_mutex);
	}
}

static void drm_fence_object_destroy(drm_file_t * priv,
				     drm_user_object_t * base)
{
	drm_device_t *dev = priv->head->dev;
	drm_fence_object_t *fence =
	    drm_user_object_entry(base, drm_fence_object_t, base);

	drm_fence_usage_deref_locked(dev, fence);
}

static int fence_signaled(drm_device_t * dev, drm_fence_object_t * fence,
			  uint32_t mask, int poke_flush)
{
	unsigned long flags;
	int signaled;
	drm_fence_manager_t *fm = &dev->fm;
	drm_fence_driver_t *driver = dev->driver->fence_driver;

	if (poke_flush)
		driver->poke_flush(dev);
	read_lock_irqsave(&fm->lock, flags);
	signaled =
	    (fence->type & mask & fence->signaled) == (fence->type & mask);
	read_unlock_irqrestore(&fm->lock, flags);

	return signaled;
}

static void drm_fence_flush_exe(drm_fence_manager_t * fm,
				drm_fence_driver_t * driver, uint32_t sequence)
{
	uint32_t diff;

	if (!fm->pending_exe_flush) {
		struct list_head *list;

		/*
		 * Last_exe_flush is invalid. Find oldest sequence.
		 */

		list = fm->fence_types[_DRM_FENCE_TYPE_EXE];
		if (list->next == &fm->ring) {
			return;
		} else {
			drm_fence_object_t *fence =
			    list_entry(list->next, drm_fence_object_t, ring);
			fm->last_exe_flush = (fence->sequence - 1) &
			    driver->sequence_mask;
		}
		diff = (sequence - fm->last_exe_flush) & driver->sequence_mask;
		if (diff >= driver->wrap_diff)
			return;
		fm->exe_flush_sequence = sequence;
		fm->pending_exe_flush = 1;
	} else {
		diff =
		    (sequence - fm->exe_flush_sequence) & driver->sequence_mask;
		if (diff < driver->wrap_diff) {
			fm->exe_flush_sequence = sequence;
		}
	}
}

/*
 * Make sure old fence objects are signaled before their fence sequences are
 * wrapped around and reused.
 */

static int drm_fence_object_flush(drm_device_t * dev,
				  drm_fence_object_t * fence, uint32_t type)
{
	drm_fence_manager_t *fm = &dev->fm;
	drm_fence_driver_t *driver = dev->driver->fence_driver;
	unsigned long flags;

	if (type & ~fence->type) {
		DRM_ERROR("Flush trying to extend fence type\n");
		return -EINVAL;
	}

	write_lock_irqsave(&fm->lock, flags);
	fence->flush_mask |= type;
	if (fence->submitted_flush == fence->signaled) {
		if ((fence->type & DRM_FENCE_EXE) &&
		    !(fence->submitted_flush & DRM_FENCE_EXE)) {
			drm_fence_flush_exe(fm, driver, fence->sequence);
			fence->submitted_flush |= DRM_FENCE_EXE;
		} else {
			fm->pending_flush |= (fence->flush_mask &
					      ~fence->submitted_flush);
			fence->submitted_flush = fence->flush_mask;
		}
	}
	write_unlock_irqrestore(&fm->lock, flags);
	driver->poke_flush(dev);
	return 0;
}

void drm_fence_flush_old(drm_device_t * dev, uint32_t sequence)
{
	drm_fence_manager_t *fm = &dev->fm;
	drm_fence_driver_t *driver = dev->driver->fence_driver;
	uint32_t old_sequence;
	unsigned long flags;
	drm_fence_object_t *fence;
	uint32_t diff;

	mutex_lock(&dev->struct_mutex);
	read_lock_irqsave(&fm->lock, flags);
	if (fm->ring.next == &fm->ring) {
		read_unlock_irqrestore(&fm->lock, flags);
		mutex_unlock(&dev->struct_mutex);
		return;
	}
	old_sequence = (sequence - driver->flush_diff) & driver->sequence_mask;
	fence = list_entry(fm->ring.next, drm_fence_object_t, ring);
	atomic_inc(&fence->usage);
	mutex_unlock(&dev->struct_mutex);
	diff = (old_sequence - fence->sequence) & driver->sequence_mask;
	read_unlock_irqrestore(&fm->lock, flags);
	if (diff < driver->wrap_diff) {
		drm_fence_object_flush(dev, fence, fence->type);
	}
	drm_fence_usage_deref_unlocked(dev, fence);
}

EXPORT_SYMBOL(drm_fence_flush_old);

static int drm_fence_object_wait(drm_device_t * dev, drm_fence_object_t * fence,
				 int lazy, int ignore_signals, uint32_t mask)
{
	drm_fence_manager_t *fm = &dev->fm;
	drm_fence_driver_t *driver = dev->driver->fence_driver;
	int ret = 0;
	unsigned long _end;

	if (mask & ~fence->type) {
		DRM_ERROR("Wait trying to extend fence type\n");
		return -EINVAL;
	}

	if (fence_signaled(dev, fence, mask, 0))
		return 0;

	_end = jiffies + 3 * DRM_HZ;

	drm_fence_object_flush(dev, fence, mask);
	if (lazy && driver->lazy_capable) {
		do {
			DRM_WAIT_ON(ret, fm->fence_queue, 3 * DRM_HZ,
				    fence_signaled(dev, fence, mask, 1));
			if (time_after_eq(jiffies, _end))
				break;
		} while (ret == -EINTR && ignore_signals);

		if (time_after_eq(jiffies, _end) && (ret != 0))
			ret = -EBUSY;
		return ret;

	} else {
		int signaled;
		do {
			signaled = fence_signaled(dev, fence, mask, 1);
		} while (!signaled && !time_after_eq(jiffies, _end));
		if (!signaled)
			return -EBUSY;
	}
	return 0;
}

int drm_fence_object_emit(drm_device_t * dev, drm_fence_object_t * fence,
			  uint32_t type)
{
	drm_fence_manager_t *fm = &dev->fm;
	drm_fence_driver_t *driver = dev->driver->fence_driver;
	unsigned long flags;
	uint32_t sequence;
	int ret;

	drm_fence_unring(dev, &fence->ring);
	ret = driver->emit(dev, &sequence);
	if (ret)
		return ret;

	write_lock_irqsave(&fm->lock, flags);
	fence->type = type;
	fence->flush_mask = 0x00;
	fence->submitted_flush = 0x00;
	fence->signaled = 0x00;
	fence->sequence = sequence;
	list_add_tail(&fence->ring, &fm->ring);
	write_unlock_irqrestore(&fm->lock, flags);
	return 0;
}

int drm_fence_object_init(drm_device_t * dev, uint32_t type, int emit,
			  drm_fence_object_t * fence)
{
	int ret = 0;
	unsigned long flags;
	drm_fence_manager_t *fm = &dev->fm;

	mutex_lock(&dev->struct_mutex);
	atomic_set(&fence->usage, 1);
	mutex_unlock(&dev->struct_mutex);

	write_lock_irqsave(&fm->lock, flags);
	INIT_LIST_HEAD(&fence->ring);
	fence->type = type;
	fence->flush_mask = 0;
	fence->submitted_flush = 0;
	fence->signaled = 0;
	fence->sequence = 0;
	write_unlock_irqrestore(&fm->lock, flags);
	if (emit) {
		ret = drm_fence_object_emit(dev, fence, type);
	}
	return ret;
}

EXPORT_SYMBOL(drm_fence_object_init);

static int drm_fence_object_create(drm_file_t * priv, uint32_t type,
				   int emit, int shareable,
				   uint32_t * user_handle,
				   drm_fence_object_t ** c_fence)
{
	drm_device_t *dev = priv->head->dev;
	int ret;
	drm_fence_object_t *fence;

	fence = drm_calloc(1, sizeof(*fence), DRM_MEM_FENCE);
	if (!fence)
		return -ENOMEM;
	ret = drm_fence_object_init(dev, type, emit, fence);
	if (ret) {
		drm_fence_usage_deref_unlocked(dev, fence);
		return ret;
	}

	mutex_lock(&dev->struct_mutex);
	ret = drm_add_user_object(priv, &fence->base, shareable);
	mutex_unlock(&dev->struct_mutex);
	if (ret) {
		drm_fence_usage_deref_unlocked(dev, fence);
		*c_fence = NULL;
		*user_handle = 0;
		return ret;
	}
	fence->base.type = drm_fence_type;
	fence->base.remove = &drm_fence_object_destroy;
	*user_handle = fence->base.hash.key;
	*c_fence = fence;

	return 0;
}

void drm_fence_manager_init(drm_device_t * dev)
{
	drm_fence_manager_t *fm = &dev->fm;
	drm_fence_driver_t *fed = dev->driver->fence_driver;
	int i;

	fm->lock = RW_LOCK_UNLOCKED;
	INIT_LIST_HEAD(&fm->ring);
	fm->pending_flush = 0;
	DRM_INIT_WAITQUEUE(&fm->fence_queue);
	fm->initialized = 0;
	if (fed) {
		fm->initialized = 1;
		for (i = 0; i < fed->no_types; ++i) {
			fm->fence_types[i] = &fm->ring;
		}
	}
}

void drm_fence_manager_takedown(drm_device_t * dev)
{
}

drm_fence_object_t *drm_lookup_fence_object(drm_file_t * priv, uint32_t handle)
{
	drm_device_t *dev = priv->head->dev;
	drm_user_object_t *uo;
	drm_fence_object_t *fence;

	mutex_lock(&dev->struct_mutex);
	uo = drm_lookup_user_object(priv, handle);
	if (!uo || (uo->type != drm_fence_type)) {
		mutex_unlock(&dev->struct_mutex);
		return NULL;
	}
	fence = drm_user_object_entry(uo, drm_fence_object_t, base);
	atomic_inc(&fence->usage);
	mutex_unlock(&dev->struct_mutex);
	return fence;
}

int drm_fence_ioctl(DRM_IOCTL_ARGS)
{
	DRM_DEVICE;
	int ret;
	drm_fence_manager_t *fm = &dev->fm;
	drm_fence_arg_t arg;
	drm_fence_object_t *fence;
	drm_user_object_t *uo;
	unsigned long flags;
	ret = 0;

	if (!fm->initialized) {
		DRM_ERROR("The DRM driver does not support fencing.\n");
		return -EINVAL;
	}

	DRM_COPY_FROM_USER_IOCTL(arg, (void __user *)data, sizeof(arg));
	switch (arg.op) {
	case drm_fence_create:{
			int emit = arg.flags & DRM_FENCE_FLAG_EMIT;
			if (emit)
				LOCK_TEST_WITH_RETURN(dev, filp);
			ret =
			    drm_fence_object_create(priv, arg.type,
						    emit,
						    arg.
						    flags &
						    DRM_FENCE_FLAG_SHAREABLE,
						    &arg.handle, &fence);
			if (ret)
				return ret;
			mutex_lock(&dev->struct_mutex);
			atomic_inc(&fence->usage);
			mutex_unlock(&dev->struct_mutex);
			break;
		}
	case drm_fence_destroy:
		mutex_lock(&dev->struct_mutex);
		uo = drm_lookup_user_object(priv, arg.handle);
		if (!uo || (uo->type != drm_fence_type) || uo->owner != priv) {
			mutex_unlock(&dev->struct_mutex);
			return -EINVAL;
		}
		ret = drm_remove_user_object(priv, uo);
		mutex_unlock(&dev->struct_mutex);
		return ret;
	case drm_fence_reference:
		ret =
		    drm_user_object_ref(priv, arg.handle, drm_fence_type, &uo);
		if (ret)
			return ret;
		fence = drm_lookup_fence_object(priv, arg.handle);
		break;
	case drm_fence_unreference:
		ret = drm_user_object_unref(priv, arg.handle, drm_fence_type);
		return ret;
	case drm_fence_signaled:
		fence = drm_lookup_fence_object(priv, arg.handle);
		if (!fence)
			return -EINVAL;
		break;
	case drm_fence_flush:
		fence = drm_lookup_fence_object(priv, arg.handle);
		if (!fence)
			return -EINVAL;
		ret = drm_fence_object_flush(dev, fence, arg.type);
		break;
	case drm_fence_wait:
		fence = drm_lookup_fence_object(priv, arg.handle);
		if (!fence)
			return -EINVAL;
		ret =
		    drm_fence_object_wait(dev, fence,
					  arg.flags & DRM_FENCE_FLAG_WAIT_LAZY,
					  arg.
					  flags &
					  DRM_FENCE_FLAG_WAIT_IGNORE_SIGNALS,
					  arg.type);
		break;
	case drm_fence_emit:
		LOCK_TEST_WITH_RETURN(dev, filp);
		fence = drm_lookup_fence_object(priv, arg.handle);
		if (!fence)
			return -EINVAL;
		ret = drm_fence_object_emit(dev, fence, arg.type);
		break;
	default:
		return -EINVAL;
	}
	read_lock_irqsave(&fm->lock, flags);
	arg.type = fence->type;
	arg.signaled = fence->signaled;
	read_unlock_irqrestore(&fm->lock, flags);
	drm_fence_usage_deref_unlocked(dev, fence);

	DRM_COPY_TO_USER_IOCTL((void __user *)data, arg, sizeof(arg));
	return ret;
}