diff options
Diffstat (limited to 'sound/core/isadma.c')
-rw-r--r-- | sound/core/isadma.c | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/sound/core/isadma.c b/sound/core/isadma.c new file mode 100644 index 00000000000..1a378951da5 --- /dev/null +++ b/sound/core/isadma.c @@ -0,0 +1,103 @@ +/* + * ISA DMA support functions + * Copyright (c) by Jaroslav Kysela <perex@suse.cz> + * + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + */ + +/* + * Defining following add some delay. Maybe this helps for some broken + * ISA DMA controllers. + */ + +#undef HAVE_REALLY_SLOW_DMA_CONTROLLER + +#include <sound/driver.h> +#include <sound/core.h> +#include <asm/dma.h> + +/** + * snd_dma_program - program an ISA DMA transfer + * @dma: the dma number + * @addr: the physical address of the buffer + * @size: the DMA transfer size + * @mode: the DMA transfer mode, DMA_MODE_XXX + * + * Programs an ISA DMA transfer for the given buffer. + */ +void snd_dma_program(unsigned long dma, + unsigned long addr, unsigned int size, + unsigned short mode) +{ + unsigned long flags; + + flags = claim_dma_lock(); + disable_dma(dma); + clear_dma_ff(dma); + set_dma_mode(dma, mode); + set_dma_addr(dma, addr); + set_dma_count(dma, size); + if (!(mode & DMA_MODE_NO_ENABLE)) + enable_dma(dma); + release_dma_lock(flags); +} + +/** + * snd_dma_disable - stop the ISA DMA transfer + * @dma: the dma number + * + * Stops the ISA DMA transfer. + */ +void snd_dma_disable(unsigned long dma) +{ + unsigned long flags; + + flags = claim_dma_lock(); + clear_dma_ff(dma); + disable_dma(dma); + release_dma_lock(flags); +} + +/** + * snd_dma_pointer - return the current pointer to DMA transfer buffer in bytes + * @dma: the dma number + * @size: the dma transfer size + * + * Returns the current pointer in DMA tranfer buffer in bytes + */ +unsigned int snd_dma_pointer(unsigned long dma, unsigned int size) +{ + unsigned long flags; + unsigned int result; + + flags = claim_dma_lock(); + clear_dma_ff(dma); + if (!isa_dma_bridge_buggy) + disable_dma(dma); + result = get_dma_residue(dma); + if (!isa_dma_bridge_buggy) + enable_dma(dma); + release_dma_lock(flags); +#ifdef CONFIG_SND_DEBUG + if (result > size) + snd_printk(KERN_ERR "pointer (0x%x) for DMA #%ld is greater than transfer size (0x%x)\n", result, dma, size); +#endif + if (result >= size || result == 0) + return 0; + else + return size - result; +} |