Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 *  ISA DMA support functions

 *  Copyright (c) by Jaroslav Kysela <perex@perex.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);

}

EXPORT_SYMBOL(snd_dma_program);

/**

 * 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);

}

EXPORT_SYMBOL(snd_dma_disable);

/**

 * 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;

}

EXPORT_SYMBOL(snd_dma_pointer);