1
2 /*
3 **********************************************************************
4 * emuadxmg.c - Address space manager for emu10k1 driver
5 * Copyright 1999, 2000 Creative Labs, Inc.
6 *
7 **********************************************************************
8 *
9 * Date Author Summary of changes
10 * ---- ------ ------------------
11 * October 20, 1999 Bertrand Lee base code release
12 *
13 **********************************************************************
14 *
15 * This program is free software; you can redistribute it and/or
16 * modify it under the terms of the GNU General Public License as
17 * published by the Free Software Foundation; either version 2 of
18 * the License, or (at your option) any later version.
19 *
20 * This program is distributed in the hope that it will be useful,
21 * but WITHOUT ANY WARRANTY; without even the implied warranty of
22 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
23 * GNU General Public License for more details.
24 *
25 * You should have received a copy of the GNU General Public
26 * License along with this program; if not, write to the Free
27 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139,
28 * USA.
29 *
30 **********************************************************************
31 */
32
33 #include "hwaccess.h"
34
35 /* Allocates emu address space */
36
emu10k1_addxmgr_alloc(u32 size,struct emu10k1_card * card)37 int emu10k1_addxmgr_alloc(u32 size, struct emu10k1_card *card)
38 {
39 u16 *pagetable = card->emupagetable;
40 u16 index = 0;
41 u16 numpages;
42 unsigned long flags;
43
44 /* Convert bytes to pages */
45 numpages = (size / EMUPAGESIZE) + ((size % EMUPAGESIZE) ? 1 : 0);
46
47 spin_lock_irqsave(&card->lock, flags);
48
49 while (index < (MAXPAGES - 1)) {
50 if (pagetable[index] & 0x8000) {
51 /* This block of pages is in use, jump to the start of the next block. */
52 index += (pagetable[index] & 0x7fff);
53 } else {
54 /* Found free block */
55 if (pagetable[index] >= numpages) {
56
57 /* Block is large enough */
58
59 /* If free block is larger than the block requested
60 * then adjust the size of the block remaining */
61 if (pagetable[index] > numpages)
62 pagetable[index + numpages] = pagetable[index] - numpages;
63
64 pagetable[index] = (numpages | 0x8000); /* Mark block as used */
65
66 spin_unlock_irqrestore(&card->lock, flags);
67
68 return index;
69 } else {
70 /* Block too small, jump to the start of the next block */
71 index += pagetable[index];
72 }
73 }
74 }
75
76 spin_unlock_irqrestore(&card->lock, flags);
77
78 return -1;
79 }
80
81 /* Frees a previously allocated emu address space. */
82
emu10k1_addxmgr_free(struct emu10k1_card * card,int index)83 void emu10k1_addxmgr_free(struct emu10k1_card *card, int index)
84 {
85 u16 *pagetable = card->emupagetable;
86 u16 origsize = 0;
87 unsigned long flags;
88
89 spin_lock_irqsave(&card->lock, flags);
90
91 if (pagetable[index] & 0x8000) {
92 /* Block is allocated - mark block as free */
93 origsize = pagetable[index] & 0x7fff;
94 pagetable[index] = origsize;
95
96 /* If next block is free, we concat both blocks */
97 if (!(pagetable[index + origsize] & 0x8000))
98 pagetable[index] += pagetable[index + origsize] & 0x7fff;
99 }
100
101 spin_unlock_irqrestore(&card->lock, flags);
102
103 return;
104 }
105