/* -*- 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        Dual MIT/GPLv2

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*/ /**************************************************************************/

#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, "%llu", 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;
}