/*
 * Copyright (c) 2004 Topspin Communications.  All rights reserved.
 * Copyright (c) 2005 Open Grid Computing, Inc. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * 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. 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/errno.h>
#include <linux/bitmap.h>

#include "c2.h"

static int c2_alloc_mqsp_chunk(struct c2_dev *c2dev, gfp_t gfp_mask,
			       struct sp_chunk **head)
{
	int i;
	struct sp_chunk *new_head;
	dma_addr_t dma_addr;

	new_head = dma_alloc_coherent(&c2dev->pcidev->dev, PAGE_SIZE,
				      &dma_addr, gfp_mask);
	if (new_head == NULL)
		return -ENOMEM;

	new_head->dma_addr = dma_addr;
	dma_unmap_addr_set(new_head, mapping, new_head->dma_addr);

	new_head->next = NULL;
	new_head->head = 0;

	/* build list where each index is the next free slot */
	for (i = 0;
	     i < (PAGE_SIZE - sizeof(struct sp_chunk) -
		  sizeof(u16)) / sizeof(u16) - 1;
	     i++) {
		new_head->shared_ptr[i] = i + 1;
	}
	/* terminate list */
	new_head->shared_ptr[i] = 0xFFFF;

	*head = new_head;
	return 0;
}

int c2_init_mqsp_pool(struct c2_dev *c2dev, gfp_t gfp_mask,
		      struct sp_chunk **root)
{
	return c2_alloc_mqsp_chunk(c2dev, gfp_mask, root);
}

void c2_free_mqsp_pool(struct c2_dev *c2dev, struct sp_chunk *root)
{
	struct sp_chunk *next;

	while (root) {
		next = root->next;
		dma_free_coherent(&c2dev->pcidev->dev, PAGE_SIZE, root,
				  dma_unmap_addr(root, mapping));
		root = next;
	}
}

__be16 *c2_alloc_mqsp(struct c2_dev *c2dev, struct sp_chunk *head,
		      dma_addr_t *dma_addr, gfp_t gfp_mask)
{
	u16 mqsp;

	while (head) {
		mqsp = head->head;
		if (mqsp != 0xFFFF) {
			head->head = head->shared_ptr[mqsp];
			break;
		} else if (head->next == NULL) {
			if (c2_alloc_mqsp_chunk(c2dev, gfp_mask, &head->next) ==
			    0) {
				head = head->next;
				mqsp = head->head;
				head->head = head->shared_ptr[mqsp];
				break;
			} else
				return NULL;
		} else
			head = head->next;
	}
	if (head) {
		*dma_addr = head->dma_addr +
			    ((unsigned long) &(head->shared_ptr[mqsp]) -
			     (unsigned long) head);
		pr_debug("%s addr %p dma_addr %llx\n", __func__,
			 &(head->shared_ptr[mqsp]), (unsigned long long) *dma_addr);
		return (__force __be16 *) &(head->shared_ptr[mqsp]);
	}
	return NULL;
}

void c2_free_mqsp(__be16 *mqsp)
{
	struct sp_chunk *head;
	u16 idx;

	/* The chunk containing this ptr begins at the page boundary */
	head = (struct sp_chunk *) ((unsigned long) mqsp & PAGE_MASK);

	/* Link head to new mqsp */
	*mqsp = (__force __be16) head->head;

	/* Compute the shared_ptr index */
	idx = ((unsigned long) mqsp & ~PAGE_MASK) >> 1;
	idx -= (unsigned long) &(((struct sp_chunk *) 0)->shared_ptr[0]) >> 1;

	/* Point this index at the head */
	head->shared_ptr[idx] = head->head;

	/* Point head at this index */
	head->head = idx;
}
