path: root/sound/oss/dmasound/dmasound_atari.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 *  linux/sound/oss/dmasound/dmasound_atari.c
 *
 *  Atari TT and Falcon DMA Sound Driver
 *
 *  See linux/sound/oss/dmasound/dmasound_core.c for copyright and credits
 *  prior to 28/01/2001
 *
 *  28/01/2001 [0.1] Iain Sandoe
 *		     - added versioning
 *		     - put in and populated the hardware_afmts field.
 *             [0.2] - put in SNDCTL_DSP_GETCAPS value.
 *  01/02/2001 [0.3] - put in default hard/soft settings.
 */


#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/soundcard.h>
#include <linux/mm.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>

#include <linux/uaccess.h>
#include <asm/atariints.h>
#include <asm/atari_stram.h>

#include "dmasound.h"

#define DMASOUND_ATARI_REVISION 0
#define DMASOUND_ATARI_EDITION 3

extern void atari_microwire_cmd(int cmd);

static int is_falcon;
static int write_sq_ignore_int;	/* ++TeSche: used for Falcon */

static int expand_bal;	/* Balance factor for expanding (not volume!) */
static int expand_data;	/* Data for expanding */


/*** Translations ************************************************************/


/* ++TeSche: radically changed for new expanding purposes...
 *
 * These two routines now deal with copying/expanding/translating the samples
 * from user space into our buffer at the right frequency. They take care about
 * how much data there's actually to read, how much buffer space there is and
 * to convert samples into the right frequency/encoding. They will only work on
 * complete samples so it may happen they leave some bytes in the input stream
 * if the user didn't write a multiple of the current sample size. They both
 * return the number of bytes they've used from both streams so you may detect
 * such a situation. Luckily all programs should be able to cope with that.
 *
 * I think I've optimized anything as far as one can do in plain C, all
 * variables should fit in registers and the loops are really short. There's
 * one loop for every possible situation. Writing a more generalized and thus
 * parameterized loop would only produce slower code. Feel free to optimize
 * this in assembler if you like. :)
 *
 * I think these routines belong here because they're not yet really hardware
 * independent, especially the fact that the Falcon can play 16bit samples
 * only in stereo is hardcoded in both of them!
 *
 * ++geert: split in even more functions (one per format)
 */

static ssize_t ata_ct_law(const u_char __user *userPtr, size_t userCount,
			  u_char frame[], ssize_t *frameUsed,
			  ssize_t frameLeft);
static ssize_t ata_ct_s8(const u_char __user *userPtr, size_t userCount,
			 u_char frame[], ssize_t *frameUsed,
			 ssize_t frameLeft);
static ssize_t ata_ct_u8(const u_char __user *userPtr, size_t userCount,
			 u_char frame[], ssize_t *frameUsed,
			 ssize_t frameLeft);
static ssize_t ata_ct_s16be(const u_char __user *userPtr, size_t userCount,
			    u_char frame[], ssize_t *frameUsed,
			    ssize_t frameLeft);
static ssize_t ata_ct_u16be(const u_char __user *userPtr, size_t userCount,
			    u_char frame[], ssize_t *frameUsed,
			    ssize_t frameLeft);
static ssize_t ata_ct_s16le(const u_char __user *userPtr, size_t userCount,
			    u_char frame[], ssize_t *frameUsed,
			    ssize_t frameLeft);
static ssize_t ata_ct_u16le(const u_char __user *userPtr, size_t userCount,
			    u_char frame[], ssize_t *frameUsed,
			    ssize_t frameLeft);
static ssize_t ata_ctx_law(const u_char __user *userPtr, size_t userCount,
			   u_char frame[], ssize_t *frameUsed,
			   ssize_t frameLeft);
static ssize_t ata_ctx_s8(const u_char __user *userPtr, size_t userCount,
			  u_char frame[], ssize_t *frameUsed,
			  ssize_t frameLeft);
static ssize_t ata_ctx_u8(const u_char __user *userPtr, size_t userCount,
			  u_char frame[], ssize_t *frameUsed,
			  ssize_t frameLeft);
static ssize_t ata_ctx_s16be(const u_char __user *userPtr, size_t userCount,