/* -*- mode: c; indent-tabs-mode: t; c-basic-offset: 8; tab-width: 8 -*- */
/* vi: set ts=8 sw=8 sts=8: */
/*************************************************************************/ /*!
@File
@Codingstyle    LinuxKernel
@Copyright      Copyright (c) Imagination Technologies Ltd. All Rights Reserved
@License        MIT

The contents of this file are subject to the MIT license as set out below.

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.

This License is also included in this distribution in the file called
"MIT-COPYING".

EXCEPT AS OTHERWISE STATED IN A NEGOTIATED AGREEMENT: (A) 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; AND (B) IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS 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 <linux/kernel.h>
#include <linux/spinlock_types.h>
#include <linux/atomic.h>
#include <linux/slab.h>
#include <linux/printk.h>
#include <linux/bug.h>

#include "pvr_sw_fence.h"

struct pvr_sw_fence_context {
	struct kref kref;
	unsigned int context;
	char context_name[32];
	char driver_name[32];
	atomic_t seqno;
	atomic_t fence_count;
};

struct pvr_sw_fence {
	struct dma_fence base;
	struct pvr_sw_fence_context *fence_context;
	spinlock_t lock;
};

#define to_pvr_sw_fence(fence) container_of(fence, struct pvr_sw_fence, base)

const char *pvr_sw_fence_context_name(struct pvr_sw_fence_context *fctx)
{
	return fctx->context_name;
}

void pvr_sw_fence_context_value_str(struct pvr_sw_fence_context *fctx,
				    char *str, int size)
{
	snprintf(str, size, "%d", atomic_read(&fctx->seqno));
}

static inline unsigned
pvr_sw_fence_context_seqno_next(struct pvr_sw_fence_context *fence_context)
{
	return atomic_inc_return(&fence_context->seqno) - 1;
}

static const char *pvr_sw_fence_get_driver_name(struct dma_fence *fence)
{
	struct pvr_sw_fence *pvr_sw_fence = to_pvr_sw_fence(fence);

	return pvr_sw_fence->fence_context->driver_name;
}

static const char *pvr_sw_fence_get_timeline_name(struct dma_fence *fence)
{
	struct pvr_sw_fence *pvr_sw_fence = to_pvr_sw_fence(fence);

	return pvr_sw_fence_context_name(pvr_sw_fence->fence_context);
}

static void pvr_sw_fence_value_str(struct dma_fence *fence, char *str, int size)
{
	snprintf(str, size, "%d", fence->seqno);
}

static void pvr_sw_fence_timeline_value_str(struct dma_fence *fence,
					    char *str, int size)
{
	struct pvr_sw_fence *pvr_sw_fence = to_pvr_sw_fence(fence);

	pvr_sw_fence_context_value_str(pvr_sw_fence->fence_context, str, size);
}

static bool pvr_sw_fence_enable_signaling(struct dma_fence *fence)
{
	return true;
}

static void pvr_sw_fence_context_destroy_kref(struct kref *kref)
{
	struct pvr_sw_fence_context *fence_context =
		container_of(kref, struct pvr_sw_fence_context, kref);
	unsigned int fence_count;

	fence_count = atomic_read(&fence_context->fence_count);
	if (WARN_ON(fence_count))
		pr_debug("%s context has %u fence(s) remaining\n",
			 fence_context->context_name, fence_count);

	kfree(fence_context);
}

static void pvr_sw_fence_release(struct dma_fence *fence)
{
	struct pvr_sw_fence *pvr_sw_fence = to_pvr_sw_fence(fence);

	atomic_dec(&pvr_sw_fence->fence_context->fence_count);
	kref_put(&pvr_sw_fence->fence_context->kref,
		pvr_sw_fence_context_destroy_kref);
	kfree(pvr_sw_fence);
}

static const struct dma_fence_ops pvr_sw_fence_ops = {
	.get_driver_name = pvr_sw_fence_get_driver_name,
	.get_timeline_name = pvr_sw_fence_get_timeline_name,
	.fence_value_str = pvr_sw_fence_value_str,
	.timeline_value_str = pvr_sw_fence_timeline_value_str,
	.enable_signaling = pvr_sw_fence_enable_signaling,
	.wait = dma_fence_default_wait,
	.release = pvr_sw_fence_release,
};

struct pvr_sw_fence_context *
pvr_sw_fence_context_create(const char *context_name, const char *driver_name)
{
	struct pvr_sw_fence_context *fence_context;

	fence_context = kmalloc(sizeof(*fence_context), GFP_KERNEL);
	if (!fence_context)
		return NULL;

	fence_context->context = dma_fence_context_alloc(1);
	strlcpy(fence_context->context_name, context_name, 
		sizeof(fence_context->context_name));
	strlcpy(fence_context->driver_name, driver_name, 
		sizeof(fence_context->driver_name));
	atomic_set(&fence_context->seqno, 0);
	atomic_set(&fence_context->fence_count, 0);
	kref_init(&fence_context->kref);

	return fence_context;
}

void pvr_sw_fence_context_destroy(struct pvr_sw_fence_context *fence_context)
{
	kref_put(&fence_context->kref, pvr_sw_fence_context_destroy_kref);
}

struct dma_fence *
pvr_sw_fence_create(struct pvr_sw_fence_context *fence_context)
{
	struct pvr_sw_fence *pvr_sw_fence;
	unsigned int seqno;

	pvr_sw_fence = kmalloc(sizeof(*pvr_sw_fence), GFP_KERNEL);
	if (!pvr_sw_fence)
		return NULL;

	spin_lock_init(&pvr_sw_fence->lock);
	pvr_sw_fence->fence_context = fence_context;

	seqno = pvr_sw_fence_context_seqno_next(fence_context);
	dma_fence_init(&pvr_sw_fence->base, &pvr_sw_fence_ops,
		       &pvr_sw_fence->lock, fence_context->context, seqno);

	atomic_inc(&fence_context->fence_count);
	kref_get(&fence_context->kref);

	return &pvr_sw_fence->base;
}