1/*
2 * Copyright (c) 2004 Topspin Communications.  All rights reserved.
3 * Copyright (c) 2005 Open Grid Computing, Inc. All rights reserved.
4 *
5 * This software is available to you under a choice of one of two
6 * licenses.  You may choose to be licensed under the terms of the GNU
7 * General Public License (GPL) Version 2, available from the file
8 * COPYING in the main directory of this source tree, or the
9 * OpenIB.org BSD license below:
10 *
11 *     Redistribution and use in source and binary forms, with or
12 *     without modification, are permitted provided that the following
13 *     conditions are met:
14 *
15 *      - Redistributions of source code must retain the above
16 *        copyright notice, this list of conditions and the following
17 *        disclaimer.
18 *
19 *      - Redistributions in binary form must reproduce the above
20 *        copyright notice, this list of conditions and the following
21 *        disclaimer in the documentation and/or other materials
22 *        provided with the distribution.
23 *
24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
25 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
26 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
27 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
28 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
29 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
30 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
31 * SOFTWARE.
32 */
33
34#include <linux/errno.h>
35#include <linux/bitmap.h>
36
37#include "c2.h"
38
39static int c2_alloc_mqsp_chunk(struct c2_dev *c2dev, gfp_t gfp_mask,
40			       struct sp_chunk **head)
41{
42	int i;
43	struct sp_chunk *new_head;
44	dma_addr_t dma_addr;
45
46	new_head = dma_alloc_coherent(&c2dev->pcidev->dev, PAGE_SIZE,
47				      &dma_addr, gfp_mask);
48	if (new_head == NULL)
49		return -ENOMEM;
50
51	new_head->dma_addr = dma_addr;
52	dma_unmap_addr_set(new_head, mapping, new_head->dma_addr);
53
54	new_head->next = NULL;
55	new_head->head = 0;
56
57	/* build list where each index is the next free slot */
58	for (i = 0;
59	     i < (PAGE_SIZE - sizeof(struct sp_chunk) -
60		  sizeof(u16)) / sizeof(u16) - 1;
61	     i++) {
62		new_head->shared_ptr[i] = i + 1;
63	}
64	/* terminate list */
65	new_head->shared_ptr[i] = 0xFFFF;
66
67	*head = new_head;
68	return 0;
69}
70
71int c2_init_mqsp_pool(struct c2_dev *c2dev, gfp_t gfp_mask,
72		      struct sp_chunk **root)
73{
74	return c2_alloc_mqsp_chunk(c2dev, gfp_mask, root);
75}
76
77void c2_free_mqsp_pool(struct c2_dev *c2dev, struct sp_chunk *root)
78{
79	struct sp_chunk *next;
80
81	while (root) {
82		next = root->next;
83		dma_free_coherent(&c2dev->pcidev->dev, PAGE_SIZE, root,
84				  dma_unmap_addr(root, mapping));
85		root = next;
86	}
87}
88
89__be16 *c2_alloc_mqsp(struct c2_dev *c2dev, struct sp_chunk *head,
90		      dma_addr_t *dma_addr, gfp_t gfp_mask)
91{
92	u16 mqsp;
93
94	while (head) {
95		mqsp = head->head;
96		if (mqsp != 0xFFFF) {
97			head->head = head->shared_ptr[mqsp];
98			break;
99		} else if (head->next == NULL) {
100			if (c2_alloc_mqsp_chunk(c2dev, gfp_mask, &head->next) ==
101			    0) {
102				head = head->next;
103				mqsp = head->head;
104				head->head = head->shared_ptr[mqsp];
105				break;
106			} else
107				return NULL;
108		} else
109			head = head->next;
110	}
111	if (head) {
112		*dma_addr = head->dma_addr +
113			    ((unsigned long) &(head->shared_ptr[mqsp]) -
114			     (unsigned long) head);
115		pr_debug("%s addr %p dma_addr %llx\n", __func__,
116			 &(head->shared_ptr[mqsp]), (unsigned long long) *dma_addr);
117		return (__force __be16 *) &(head->shared_ptr[mqsp]);
118	}
119	return NULL;
120}
121
122void c2_free_mqsp(__be16 *mqsp)
123{
124	struct sp_chunk *head;
125	u16 idx;
126
127	/* The chunk containing this ptr begins at the page boundary */
128	head = (struct sp_chunk *) ((unsigned long) mqsp & PAGE_MASK);
129
130	/* Link head to new mqsp */
131	*mqsp = (__force __be16) head->head;
132
133	/* Compute the shared_ptr index */
134	idx = ((unsigned long) mqsp & ~PAGE_MASK) >> 1;
135	idx -= (unsigned long) &(((struct sp_chunk *) 0)->shared_ptr[0]) >> 1;
136
137	/* Point this index at the head */
138	head->shared_ptr[idx] = head->head;
139
140	/* Point head at this index */
141	head->head = idx;
142}
143