1 /*
2  * Copyright (c) 2012-2016 VMware, Inc.  All rights reserved.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of EITHER the GNU General Public License
6  * version 2 as published by the Free Software Foundation or the BSD
7  * 2-Clause License. This program is distributed in the hope that it
8  * will be useful, but WITHOUT ANY WARRANTY; WITHOUT EVEN THE IMPLIED
9  * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
10  * See the GNU General Public License version 2 for more details at
11  * http://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html.
12  *
13  * You should have received a copy of the GNU General Public License
14  * along with this program available in the file COPYING in the main
15  * directory of this source tree.
16  *
17  * The BSD 2-Clause License
18  *
19  *     Redistribution and use in source and binary forms, with or
20  *     without modification, are permitted provided that the following
21  *     conditions are met:
22  *
23  *      - Redistributions of source code must retain the above
24  *        copyright notice, this list of conditions and the following
25  *        disclaimer.
26  *
27  *      - Redistributions in binary form must reproduce the above
28  *        copyright notice, this list of conditions and the following
29  *        disclaimer in the documentation and/or other materials
30  *        provided with the distribution.
31  *
32  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
33  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
34  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
35  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
36  * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
37  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
38  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
39  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
40  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
41  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
42  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
43  * OF THE POSSIBILITY OF SUCH DAMAGE.
44  */
45 
46 #include <linux/bitmap.h>
47 #include <linux/errno.h>
48 #include <linux/slab.h>
49 
50 #include "pvrdma.h"
51 
52 int pvrdma_uar_table_init(struct pvrdma_dev *dev)
53 {
54 	u32 num = dev->dsr->caps.max_uar;
55 	u32 mask = num - 1;
56 	struct pvrdma_id_table *tbl = &dev->uar_table.tbl;
57 
58 	if (!is_power_of_2(num))
59 		return -EINVAL;
60 
61 	tbl->last = 0;
62 	tbl->top = 0;
63 	tbl->max = num;
64 	tbl->mask = mask;
65 	spin_lock_init(&tbl->lock);
66 	tbl->table = bitmap_zalloc(num, GFP_KERNEL);
67 	if (!tbl->table)
68 		return -ENOMEM;
69 
70 	/* 0th UAR is taken by the device. */
71 	__set_bit(0, tbl->table);
72 
73 	return 0;
74 }
75 
76 void pvrdma_uar_table_cleanup(struct pvrdma_dev *dev)
77 {
78 	struct pvrdma_id_table *tbl = &dev->uar_table.tbl;
79 
80 	bitmap_free(tbl->table);
81 }
82 
83 int pvrdma_uar_alloc(struct pvrdma_dev *dev, struct pvrdma_uar_map *uar)
84 {
85 	struct pvrdma_id_table *tbl;
86 	unsigned long flags;
87 	u32 obj;
88 
89 	tbl = &dev->uar_table.tbl;
90 
91 	spin_lock_irqsave(&tbl->lock, flags);
92 	obj = find_next_zero_bit(tbl->table, tbl->max, tbl->last);
93 	if (obj >= tbl->max) {
94 		tbl->top = (tbl->top + tbl->max) & tbl->mask;
95 		obj = find_first_zero_bit(tbl->table, tbl->max);
96 	}
97 
98 	if (obj >= tbl->max) {
99 		spin_unlock_irqrestore(&tbl->lock, flags);
100 		return -ENOMEM;
101 	}
102 
103 	__set_bit(obj, tbl->table);
104 	obj |= tbl->top;
105 
106 	spin_unlock_irqrestore(&tbl->lock, flags);
107 
108 	uar->index = obj;
109 	uar->pfn = (pci_resource_start(dev->pdev, PVRDMA_PCI_RESOURCE_UAR) >>
110 		    PAGE_SHIFT) + uar->index;
111 
112 	return 0;
113 }
114 
115 void pvrdma_uar_free(struct pvrdma_dev *dev, struct pvrdma_uar_map *uar)
116 {
117 	struct pvrdma_id_table *tbl = &dev->uar_table.tbl;
118 	unsigned long flags;
119 	u32 obj;
120 
121 	obj = uar->index & (tbl->max - 1);
122 	spin_lock_irqsave(&tbl->lock, flags);
123 	__clear_bit(obj, tbl->table);
124 	tbl->last = min(tbl->last, obj);
125 	tbl->top = (tbl->top + tbl->max) & tbl->mask;
126 	spin_unlock_irqrestore(&tbl->lock, flags);
127 }
128