| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * ISA DMA support functions |
| 3 | * Copyright (c) by Jaroslav Kysela <perex@suse.cz> |
| 4 | * |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation; either version 2 of the License, or |
| 9 | * (at your option) any later version. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | * GNU General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU General Public License |
| 17 | * along with this program; if not, write to the Free Software |
| 18 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| 19 | * |
| 20 | */ |
| 21 | |
| 22 | /* |
| 23 | * Defining following add some delay. Maybe this helps for some broken |
| 24 | * ISA DMA controllers. |
| 25 | */ |
| 26 | |
| 27 | #undef HAVE_REALLY_SLOW_DMA_CONTROLLER |
| 28 | |
| 29 | #include <sound/driver.h> |
| 30 | #include <sound/core.h> |
| 31 | #include <asm/dma.h> |
| 32 | |
| 33 | /** |
| 34 | * snd_dma_program - program an ISA DMA transfer |
| 35 | * @dma: the dma number |
| 36 | * @addr: the physical address of the buffer |
| 37 | * @size: the DMA transfer size |
| 38 | * @mode: the DMA transfer mode, DMA_MODE_XXX |
| 39 | * |
| 40 | * Programs an ISA DMA transfer for the given buffer. |
| 41 | */ |
| 42 | void snd_dma_program(unsigned long dma, |
| 43 | unsigned long addr, unsigned int size, |
| 44 | unsigned short mode) |
| 45 | { |
| 46 | unsigned long flags; |
| 47 | |
| 48 | flags = claim_dma_lock(); |
| 49 | disable_dma(dma); |
| 50 | clear_dma_ff(dma); |
| 51 | set_dma_mode(dma, mode); |
| 52 | set_dma_addr(dma, addr); |
| 53 | set_dma_count(dma, size); |
| 54 | if (!(mode & DMA_MODE_NO_ENABLE)) |
| 55 | enable_dma(dma); |
| 56 | release_dma_lock(flags); |
| 57 | } |
| 58 | |
| 59 | /** |
| 60 | * snd_dma_disable - stop the ISA DMA transfer |
| 61 | * @dma: the dma number |
| 62 | * |
| 63 | * Stops the ISA DMA transfer. |
| 64 | */ |
| 65 | void snd_dma_disable(unsigned long dma) |
| 66 | { |
| 67 | unsigned long flags; |
| 68 | |
| 69 | flags = claim_dma_lock(); |
| 70 | clear_dma_ff(dma); |
| 71 | disable_dma(dma); |
| 72 | release_dma_lock(flags); |
| 73 | } |
| 74 | |
| 75 | /** |
| 76 | * snd_dma_pointer - return the current pointer to DMA transfer buffer in bytes |
| 77 | * @dma: the dma number |
| 78 | * @size: the dma transfer size |
| 79 | * |
| 80 | * Returns the current pointer in DMA tranfer buffer in bytes |
| 81 | */ |
| 82 | unsigned int snd_dma_pointer(unsigned long dma, unsigned int size) |
| 83 | { |
| 84 | unsigned long flags; |
| 85 | unsigned int result; |
| 86 | |
| 87 | flags = claim_dma_lock(); |
| 88 | clear_dma_ff(dma); |
| 89 | if (!isa_dma_bridge_buggy) |
| 90 | disable_dma(dma); |
| 91 | result = get_dma_residue(dma); |
| 92 | if (!isa_dma_bridge_buggy) |
| 93 | enable_dma(dma); |
| 94 | release_dma_lock(flags); |
| 95 | #ifdef CONFIG_SND_DEBUG |
| 96 | if (result > size) |
| 97 | snd_printk(KERN_ERR "pointer (0x%x) for DMA #%ld is greater than transfer size (0x%x)\n", result, dma, size); |
| 98 | #endif |
| 99 | if (result >= size || result == 0) |
| 100 | return 0; |
| 101 | else |
| 102 | return size - result; |
| 103 | } |