[mirror_ubuntu-jammy-kernel.git] / sound / core / isadma.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  ISA DMA support functions
 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
 */

/*
 * 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 <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
 *
 * Return: The current pointer in DMA transfer buffer in bytes.
 */
unsigned int snd_dma_pointer(unsigned long dma, unsigned int size)
{
	unsigned long flags;
	unsigned int result, result1;

	flags = claim_dma_lock();
	clear_dma_ff(dma);
	if (!isa_dma_bridge_buggy)
		disable_dma(dma);
	result = get_dma_residue(dma);
	/*
	 * HACK - read the counter again and choose higher value in order to
	 * avoid reading during counter lower byte roll over if the
	 * isa_dma_bridge_buggy is set.
	 */
	result1 = get_dma_residue(dma);
	if (!isa_dma_bridge_buggy)
		enable_dma(dma);
	release_dma_lock(flags);
	if (unlikely(result < result1))
		result = result1;
#ifdef CONFIG_SND_DEBUG
	if (result > size)
		pr_err("ALSA: 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);
Commit	Line	Data
1a59d1b8	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4 LT	2	/*
1da177e4 LT	3	* ISA DMA support functions
c1017a4c	4	* Copyright (c) by Jaroslav Kysela <perex@perex.cz>
1da177e4 LT	5	*/
	6
	7	/*
	8	* Defining following add some delay. Maybe this helps for some broken
	9	* ISA DMA controllers.
	10	*/
	11
	12	#undef HAVE_REALLY_SLOW_DMA_CONTROLLER
	13
d81a6d71	14	#include <linux/export.h>
1da177e4 LT	15	#include <sound/core.h>
	16	#include <asm/dma.h>
	17
	18	/**
	19	* snd_dma_program - program an ISA DMA transfer
	20	* @dma: the dma number
	21	* @addr: the physical address of the buffer
	22	* @size: the DMA transfer size
	23	* @mode: the DMA transfer mode, DMA_MODE_XXX
	24	*
	25	* Programs an ISA DMA transfer for the given buffer.
	26	*/
	27	void snd_dma_program(unsigned long dma,
	28	unsigned long addr, unsigned int size,
	29	unsigned short mode)
	30	{
	31	unsigned long flags;
	32
	33	flags = claim_dma_lock();
	34	disable_dma(dma);
	35	clear_dma_ff(dma);
	36	set_dma_mode(dma, mode);
	37	set_dma_addr(dma, addr);
	38	set_dma_count(dma, size);
	39	if (!(mode & DMA_MODE_NO_ENABLE))
	40	enable_dma(dma);
	41	release_dma_lock(flags);
	42	}
c0d3fb39 TI	43	EXPORT_SYMBOL(snd_dma_program);
c0d3fb39 TI	44
1da177e4 LT	45	/**
	46	* snd_dma_disable - stop the ISA DMA transfer
	47	* @dma: the dma number
	48	*
	49	* Stops the ISA DMA transfer.
	50	*/
	51	void snd_dma_disable(unsigned long dma)
	52	{
	53	unsigned long flags;
	54
	55	flags = claim_dma_lock();
	56	clear_dma_ff(dma);
	57	disable_dma(dma);
	58	release_dma_lock(flags);
	59	}
c0d3fb39 TI	60	EXPORT_SYMBOL(snd_dma_disable);
c0d3fb39 TI	61
1da177e4 LT	62	/**
	63	* snd_dma_pointer - return the current pointer to DMA transfer buffer in bytes
	64	* @dma: the dma number
	65	* @size: the dma transfer size
	66	*
eb7c06e8	67	* Return: The current pointer in DMA transfer buffer in bytes.
1da177e4 LT	68	*/
	69	unsigned int snd_dma_pointer(unsigned long dma, unsigned int size)
	70	{
	71	unsigned long flags;
8066e51a	72	unsigned int result, result1;
1da177e4 LT	73
	74	flags = claim_dma_lock();
	75	clear_dma_ff(dma);
	76	if (!isa_dma_bridge_buggy)
	77	disable_dma(dma);
	78	result = get_dma_residue(dma);
8066e51a KH	79	/*
	80	* HACK - read the counter again and choose higher value in order to
	81	* avoid reading during counter lower byte roll over if the
	82	* isa_dma_bridge_buggy is set.
	83	*/
	84	result1 = get_dma_residue(dma);
1da177e4 LT	85	if (!isa_dma_bridge_buggy)
	86	enable_dma(dma);
	87	release_dma_lock(flags);
8066e51a KH	88	if (unlikely(result < result1))
8066e51a KH	89	result = result1;
1da177e4 LT	90	#ifdef CONFIG_SND_DEBUG
1da177e4 LT	91	if (result > size)
f2f9307a	92	pr_err("ALSA: pointer (0x%x) for DMA #%ld is greater than transfer size (0x%x)\n", result, dma, size);
1da177e4 LT	93	#endif
	94	if (result >= size \|\| result == 0)
	95	return 0;
	96	else
	97	return size - result;
	98	}
c0d3fb39	99	EXPORT_SYMBOL(snd_dma_pointer);