| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | |
| 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 | |
| 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 | } |