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 } 104