/*
 * Copyright (C) 2012 ARM Limited. All rights reserved.
 * 
 * This program is free software and is provided to you under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation, and any use by you of this program is subject to the terms of such GNU licence.
 * 
 * A copy of the licence is included with the program, and can also be obtained from Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

/**
 * @file mali_sync.c
 *
 */

#include <linux/seq_file.h>
#include <linux/sync.h>
#include <linux/timer.h>

#include "mali_osk.h"
#include "mali_kernel_common.h"

struct mali_sync_timeline
{
	struct sync_timeline timeline;
	atomic_t counter;
	atomic_t signalled;
};

struct mali_sync_pt
{
	struct sync_pt pt;
	u32 order;
	s32 error;
	struct timer_list timer;
};

static void mali_sync_timed_pt_timeout(unsigned long data);

static inline struct mali_sync_timeline *to_mali_sync_timeline(struct sync_timeline *timeline)
{
	return container_of(timeline, struct mali_sync_timeline, timeline);
}

static inline struct mali_sync_pt *to_mali_sync_pt(struct sync_pt *pt)
{
	return container_of(pt, struct mali_sync_pt, pt);
}

static struct sync_pt *timeline_dup(struct sync_pt *pt)
{
	struct mali_sync_pt *mpt = to_mali_sync_pt(pt);
	struct mali_sync_pt *new_mpt;
	struct sync_pt *new_pt = sync_pt_create(pt->parent, sizeof(struct mali_sync_pt));

	if (!new_pt)
	{
		return NULL;
	}

	new_mpt = to_mali_sync_pt(new_pt);
	new_mpt->order = mpt->order;

	return new_pt;

}

static int timeline_has_signaled(struct sync_pt *pt)
{
	struct mali_sync_pt *mpt = to_mali_sync_pt(pt);
	struct mali_sync_timeline *mtl = to_mali_sync_timeline(pt->parent);
	long diff;

	if (0 != mpt->error)
	{
		return mpt->error;
	}

	diff = atomic_read(&mtl->signalled) - mpt->order;

	return diff >= 0;
}

static int timeline_compare(struct sync_pt *a, struct sync_pt *b)
{
	struct mali_sync_pt *ma = container_of(a, struct mali_sync_pt, pt);
	struct mali_sync_pt *mb = container_of(b, struct mali_sync_pt, pt);

	long diff = ma->order - mb->order;

	if (diff < 0)
	{
		return -1;
	}
	else if (diff == 0)
	{
		return 0;
	}
	else
	{
		return 1;
	}
}

static void timeline_free_pt(struct sync_pt *pt)
{
	struct mali_sync_pt *mpt = to_mali_sync_pt(pt);

	if (mpt->timer.function == mali_sync_timed_pt_timeout)
	{
		del_timer_sync(&mpt->timer);
	}
}

static void timeline_print_tl(struct seq_file *s, struct sync_timeline *sync_timeline)
{
	struct mali_sync_timeline *mtl = to_mali_sync_timeline(sync_timeline);

	seq_printf(s, "%u, %u", atomic_read(&mtl->signalled), atomic_read(&mtl->counter));
}

static void timeline_print_pt(struct seq_file *s, struct sync_pt *sync_pt)
{
	struct mali_sync_pt *mpt = to_mali_sync_pt(sync_pt);

	seq_printf(s, "%u", mpt->order);

}

static struct sync_timeline_ops mali_timeline_ops = {
	.driver_name    = "Mali",
	.dup            = timeline_dup,
	.has_signaled   = timeline_has_signaled,
	.compare        = timeline_compare,
	.free_pt        = timeline_free_pt,
	.print_obj      = timeline_print_tl,
	.print_pt       = timeline_print_pt
};

int mali_sync_timeline_is_ours(struct sync_timeline *timeline)
{
	return (timeline->ops == &mali_timeline_ops);
}

struct sync_timeline *mali_sync_timeline_alloc(const char * name)
{
	struct sync_timeline *tl;
	struct mali_sync_timeline *mtl;

	tl = sync_timeline_create(&mali_timeline_ops,
	                          sizeof(struct mali_sync_timeline), name);
	if (!tl)
	{
		return NULL;
	}

	/* Set the counter in our private struct */
	mtl = to_mali_sync_timeline(tl);
	atomic_set(&mtl->counter, 0);
	atomic_set(&mtl->signalled, 0);

	return tl;
}

struct sync_pt *mali_sync_pt_alloc(struct sync_timeline *parent)
{
	struct sync_pt *pt = sync_pt_create(parent, sizeof(struct mali_sync_pt));
	struct mali_sync_timeline *mtl = to_mali_sync_timeline(parent);
	struct mali_sync_pt *mpt;

	if (!pt)
	{
		return NULL;
	}

	mpt = to_mali_sync_pt(pt);
	mpt->order = atomic_inc_return(&mtl->counter);
	mpt->error = 0;

	return pt;
}

static void mali_sync_timed_pt_timeout(unsigned long data)
{
	struct sync_pt *pt = (struct sync_pt *)data;

	MALI_DEBUG_ASSERT_POINTER(pt);

	mali_sync_signal_pt(pt, -ETIME);
}

struct sync_pt *mali_sync_timed_pt_alloc(struct sync_timeline *parent)
{
	struct sync_pt *pt;
	struct mali_sync_pt *mpt;
	const u32 timeout = msecs_to_jiffies(MALI_SYNC_TIMED_FENCE_TIMEOUT);

	pt = mali_sync_pt_alloc(parent);
	if (NULL == pt) return NULL;
	mpt = to_mali_sync_pt(pt);

	init_timer(&mpt->timer);

	mpt->timer.function = mali_sync_timed_pt_timeout;
	mpt->timer.data = (unsigned long)pt;
	mpt->timer.expires = jiffies + timeout;

	add_timer(&mpt->timer);

	return pt;
}

/*
 * Returns 0 if sync_pt has been committed and are ready for use, -ETIME if
 * timeout already happened and the fence has been signalled.
 *
 * If an error occurs the sync point can not be used.
 */
int mali_sync_timed_commit(struct sync_pt *pt)
{
	struct mali_sync_pt *mpt = to_mali_sync_pt(pt);
	int ret;

	if (!mali_sync_timeline_is_ours(pt->parent))
	{
		return -EINVAL;
	}

	/* Stop timer */
	ret = del_timer_sync(&mpt->timer);

	if (0 == ret)
	{
		return -ETIME;
	}

	MALI_DEBUG_ASSERT(0 == timeline_has_signaled(pt));

	return 0;
}

void mali_sync_signal_pt(struct sync_pt *pt, int error)
{
	struct mali_sync_pt *mpt = to_mali_sync_pt(pt);
	struct mali_sync_timeline *mtl = to_mali_sync_timeline(pt->parent);
	int signalled;
	long diff;

	if (0 != error)
	{
		MALI_DEBUG_ASSERT(0 > error);
		mpt->error = error;
	}

	do {

		signalled = atomic_read(&mtl->signalled);

		diff = signalled - mpt->order;

		if (diff > 0)
		{
			/* The timeline is already at or ahead of this point. This should not happen unless userspace
			 * has been signalling fences out of order, so warn but don't violate the sync_pt API.
			 * The warning is only in debug builds to prevent a malicious user being able to spam dmesg.
			 */
			MALI_DEBUG_PRINT_ERROR(("Sync points were triggerd in a different order to allocation!\n"));
			return;
		}
	} while (atomic_cmpxchg(&mtl->signalled, signalled, mpt->order) != signalled);

	sync_timeline_signal(pt->parent);
}