linux/sound/core/isadma.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  ISA DMA support functions
 *  Copyright (c) by Jaroslav Kysela <[email protected]>
 */

/*
 * Defining following add some delay. Maybe this helps for some broken
 * ISA DMA controllers.
 */

#undef HAVE_REALLY_SLOW_DMA_CONTROLLER

#include <linux/export.h>
#include <linux/isa-dma.h>
#include <sound/core.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)
{ … }
EXPORT_SYMBOL(…);

/**
 * snd_dma_disable - stop the ISA DMA transfer
 * @dma: the dma number
 *
 * Stops the ISA DMA transfer.
 */
void snd_dma_disable(unsigned long dma)
{ … }
EXPORT_SYMBOL(…);

/**
 * snd_dma_pointer - return the current pointer to DMA transfer buffer in bytes
 * @dma: the dma number
 * @size: the dma transfer size
 *
 * Return: The current pointer in DMA transfer buffer in bytes.
 */
unsigned int snd_dma_pointer(unsigned long dma, unsigned int size)
{ … }
EXPORT_SYMBOL(…);

struct snd_dma_data { … };

static void __snd_release_dma(struct device *dev, void *data)
{ … }

/**
 * snd_devm_request_dma - the managed version of request_dma()
 * @dev: the device pointer
 * @dma: the dma number
 * @name: the name string of the requester
 *
 * The requested DMA will be automatically released at unbinding via devres.
 *
 * Return: zero on success, or a negative error code
 */
int snd_devm_request_dma(struct device *dev, int dma, const char *name)
{ … }
EXPORT_SYMBOL_GPL(…);