/* Copyright (c) 2017 The Linux Foundation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#include <linux/kref.h>
#include "msm_gpu.h"

void msm_submitqueue_destroy(struct kref *kref)
{
	struct msm_gpu_submitqueue *queue = container_of(kref,
		struct msm_gpu_submitqueue, ref);

	kfree(queue);
}

struct msm_gpu_submitqueue *msm_submitqueue_get(struct msm_file_private *ctx,
		u32 id)
{
	struct msm_gpu_submitqueue *entry;

	if (!ctx)
		return NULL;

	read_lock(&ctx->queuelock);

	list_for_each_entry(entry, &ctx->submitqueues, node) {
		if (entry->id == id) {
			kref_get(&entry->ref);
			read_unlock(&ctx->queuelock);

			return entry;
		}
	}

	read_unlock(&ctx->queuelock);
	return NULL;
}

void msm_submitqueue_close(struct msm_file_private *ctx)
{
	struct msm_gpu_submitqueue *entry, *tmp;

	if (!ctx)
		return;

	/*
	 * No lock needed in close and there won't
	 * be any more user ioctls coming our way
	 */
	list_for_each_entry_safe(entry, tmp, &ctx->submitqueues, node)
		msm_submitqueue_put(entry);
}

int msm_submitqueue_create(struct drm_device *drm, struct msm_file_private *ctx,
		u32 prio, u32 flags, u32 *id)
{
	struct msm_drm_private *priv = drm->dev_private;
	struct msm_gpu_submitqueue *queue;

	if (!ctx)
		return -ENODEV;

	queue = kzalloc(sizeof(*queue), GFP_KERNEL);

	if (!queue)
		return -ENOMEM;

	kref_init(&queue->ref);
	queue->flags = flags;

	if (priv->gpu) {
		if (prio >= priv->gpu->nr_rings) {
			kfree(queue);
			return -EINVAL;
		}

		queue->prio = prio;
	}

	write_lock(&ctx->queuelock);

	queue->id = ctx->queueid++;

	if (id)
		*id = queue->id;

	list_add_tail(&queue->node, &ctx->submitqueues);

	write_unlock(&ctx->queuelock);

	return 0;
}

int msm_submitqueue_init(struct drm_device *drm, struct msm_file_private *ctx)
{
	struct msm_drm_private *priv = drm->dev_private;
	int default_prio;

	if (!ctx)
		return 0;

	/*
	 * Select priority 2 as the "default priority" unless nr_rings is less
	 * than 2 and then pick the lowest pirority
	 */
	default_prio = priv->gpu ?
		clamp_t(uint32_t, 2, 0, priv->gpu->nr_rings - 1) : 0;

	INIT_LIST_HEAD(&ctx->submitqueues);

	rwlock_init(&ctx->queuelock);

	return msm_submitqueue_create(drm, ctx, default_prio, 0, NULL);
}

int msm_submitqueue_remove(struct msm_file_private *ctx, u32 id)
{
	struct msm_gpu_submitqueue *entry;

	if (!ctx)
		return 0;

	/*
	 * id 0 is the "default" queue and can't be destroyed
	 * by the user
	 */
	if (!id)
		return -ENOENT;

	write_lock(&ctx->queuelock);

	list_for_each_entry(entry, &ctx->submitqueues, node) {
		if (entry->id == id) {
			list_del(&entry->node);
			write_unlock(&ctx->queuelock);

			msm_submitqueue_put(entry);
			return 0;
		}
	}

	write_unlock(&ctx->queuelock);
	return -ENOENT;
}