sound/isa/sb/emu8000_pcm.c - kernel/msm-4.9 - Gitiles

 /*
  * pcm emulation on emu8000 wavetable
  *
  *  Copyright (C) 2002 Takashi Iwai <tiwai@suse.de>
  *
  *   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
  */

 #include "emu8000_local.h"
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <sound/initval.h>
 #include <sound/pcm.h>

 /*
  * define the following if you want to use this pcm with non-interleaved mode
  */
 /* #define USE_NONINTERLEAVE */

 /* NOTE: for using the non-interleaved mode with alsa-lib, you have to set
  * mmap_emulation flag to 1 in your .asoundrc, such like
  *
  *	pcm.emu8k {
  *		type plug
  *		slave.pcm {
  *			type hw
  *			card 0
  *			device 1
  *			mmap_emulation 1
  *		}
  *	}
  *
  * besides, for the time being, the non-interleaved mode doesn't work well on
  * alsa-lib...
  */


 struct snd_emu8k_pcm {
 	struct snd_emu8000 *emu;
 	struct snd_pcm_substream *substream;

 	unsigned int allocated_bytes;
 	struct snd_util_memblk *block;
 	unsigned int offset;
 	unsigned int buf_size;
 	unsigned int period_size;
 	unsigned int loop_start[2];
 	unsigned int pitch;
 	int panning[2];
 	int last_ptr;
 	int period_pos;
 	int voices;
 	unsigned int dram_opened: 1;
 	unsigned int running: 1;
 	unsigned int timer_running: 1;
 	struct timer_list timer;
 	spinlock_t timer_lock;
 };

 #define LOOP_BLANK_SIZE		8


 /*
  * open up channels for the simultaneous data transfer and playback
  */
 static int
 emu8k_open_dram_for_pcm(struct snd_emu8000 *emu, int channels)
 {
 	int i;

 	/* reserve up to 2 voices for playback */
 	snd_emux_lock_voice(emu->emu, 0);
 	if (channels > 1)
 		snd_emux_lock_voice(emu->emu, 1);

 	/* reserve 28 voices for loading */
 	for (i = channels + 1; i < EMU8000_DRAM_VOICES; i++) {
 		unsigned int mode = EMU8000_RAM_WRITE;
 		snd_emux_lock_voice(emu->emu, i);
 #ifndef USE_NONINTERLEAVE
 		if (channels > 1 && (i & 1) != 0)
 			mode |= EMU8000_RAM_RIGHT;
 #endif
 		snd_emu8000_dma_chan(emu, i, mode);
 	}

 	/* assign voice 31 and 32 to ROM */
 	EMU8000_VTFT_WRITE(emu, 30, 0);
 	EMU8000_PSST_WRITE(emu, 30, 0x1d8);
 	EMU8000_CSL_WRITE(emu, 30, 0x1e0);
 	EMU8000_CCCA_WRITE(emu, 30, 0x1d8);
 	EMU8000_VTFT_WRITE(emu, 31, 0);
 	EMU8000_PSST_WRITE(emu, 31, 0x1d8);
 	EMU8000_CSL_WRITE(emu, 31, 0x1e0);
 	EMU8000_CCCA_WRITE(emu, 31, 0x1d8);

 	return 0;
 }

 /*
  */
 static void
 snd_emu8000_write_wait(struct snd_emu8000 *emu, int can_schedule)
 {
 	while ((EMU8000_SMALW_READ(emu) & 0x80000000) != 0) {
 		if (can_schedule) {
 			schedule_timeout_interruptible(1);
 			if (signal_pending(current))
 				break;
 		}
 	}
 }

 /*
  * close all channels
  */
 static void
 emu8k_close_dram(struct snd_emu8000 *emu)
 {
 	int i;

 	for (i = 0; i < 2; i++)
 		snd_emux_unlock_voice(emu->emu, i);
 	for (; i < EMU8000_DRAM_VOICES; i++) {
 		snd_emu8000_dma_chan(emu, i, EMU8000_RAM_CLOSE);
 		snd_emux_unlock_voice(emu->emu, i);
 	}
 }

 /*
  * convert Hz to AWE32 rate offset (see emux/soundfont.c)
  */

 #define OFFSET_SAMPLERATE	1011119		/* base = 44100 */
 #define SAMPLERATE_RATIO	4096

 static int calc_rate_offset(int hz)
 {
 	return snd_sf_linear_to_log(hz, OFFSET_SAMPLERATE, SAMPLERATE_RATIO);
 }


 /*
  */

 static struct snd_pcm_hardware emu8k_pcm_hw = {
 #ifdef USE_NONINTERLEAVE
 	.info =			SNDRV_PCM_INFO_NONINTERLEAVED,
 #else
 	.info =			SNDRV_PCM_INFO_INTERLEAVED,
 #endif
 	.formats =		SNDRV_PCM_FMTBIT_S16_LE,
 	.rates =		SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_48000,
 	.rate_min =		4000,
 	.rate_max =		48000,
 	.channels_min =		1,
 	.channels_max =		2,
 	.buffer_bytes_max =	(128*1024),
 	.period_bytes_min =	1024,
 	.period_bytes_max =	(128*1024),
 	.periods_min =		2,
 	.periods_max =		1024,
 	.fifo_size =		0,

 };

 /*
  * get the current position at the given channel from CCCA register
  */
 static inline int emu8k_get_curpos(struct snd_emu8k_pcm *rec, int ch)
 {
 	int val = EMU8000_CCCA_READ(rec->emu, ch) & 0xfffffff;
 	val -= rec->loop_start[ch] - 1;
 	return val;
 }


 /*
  * timer interrupt handler
  * check the current position and update the period if necessary.
  */
 static void emu8k_pcm_timer_func(unsigned long data)
 {
 	struct snd_emu8k_pcm *rec = (struct snd_emu8k_pcm *)data;
 	int ptr, delta;

 	spin_lock(&rec->timer_lock);
 	/* update the current pointer */
 	ptr = emu8k_get_curpos(rec, 0);
 	if (ptr < rec->last_ptr)
 		delta = ptr + rec->buf_size - rec->last_ptr;
 	else
 		delta = ptr - rec->last_ptr;
 	rec->period_pos += delta;
 	rec->last_ptr = ptr;

 	/* reprogram timer */
 	rec->timer.expires = jiffies + 1;
 	add_timer(&rec->timer);

 	/* update period */
 	if (rec->period_pos >= (int)rec->period_size) {
 		rec->period_pos %= rec->period_size;
 		spin_unlock(&rec->timer_lock);
 		snd_pcm_period_elapsed(rec->substream);
 		return;
 	}
 	spin_unlock(&rec->timer_lock);
 }


 /*
  * open pcm
  * creating an instance here
  */
 static int emu8k_pcm_open(struct snd_pcm_substream *subs)
 {
 	struct snd_emu8000 *emu = snd_pcm_substream_chip(subs);
 	struct snd_emu8k_pcm *rec;
 	struct snd_pcm_runtime *runtime = subs->runtime;

 	rec = kzalloc(sizeof(*rec), GFP_KERNEL);
 	if (! rec)
 		return -ENOMEM;

 	rec->emu = emu;
 	rec->substream = subs;
 	runtime->private_data = rec;

 	spin_lock_init(&rec->timer_lock);
 	init_timer(&rec->timer);
 	rec->timer.function = emu8k_pcm_timer_func;
 	rec->timer.data = (unsigned long)rec;

 	runtime->hw = emu8k_pcm_hw;
 	runtime->hw.buffer_bytes_max = emu->mem_size - LOOP_BLANK_SIZE * 3;
 	runtime->hw.period_bytes_max = runtime->hw.buffer_bytes_max / 2;

 	/* use timer to update periods.. (specified in msec) */
 	snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_PERIOD_TIME,
 				     (1000000 + HZ - 1) / HZ, UINT_MAX);

 	return 0;
 }

 static int emu8k_pcm_close(struct snd_pcm_substream *subs)
 {
 	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
 	kfree(rec);
 	subs->runtime->private_data = NULL;
 	return 0;
 }

 /*
  * calculate pitch target
  */
 static int calc_pitch_target(int pitch)
 {
 	int ptarget = 1 << (pitch >> 12);
 	if (pitch & 0x800) ptarget += (ptarget * 0x102e) / 0x2710;
 	if (pitch & 0x400) ptarget += (ptarget * 0x764) / 0x2710;
 	if (pitch & 0x200) ptarget += (ptarget * 0x389) / 0x2710;
 	ptarget += (ptarget >> 1);
 	if (ptarget > 0xffff) ptarget = 0xffff;
 	return ptarget;
 }

 /*
  * set up the voice
  */
 static void setup_voice(struct snd_emu8k_pcm *rec, int ch)
 {
 	struct snd_emu8000 *hw = rec->emu;
 	unsigned int temp;

 	/* channel to be silent and idle */
 	EMU8000_DCYSUSV_WRITE(hw, ch, 0x0080);
 	EMU8000_VTFT_WRITE(hw, ch, 0x0000FFFF);
 	EMU8000_CVCF_WRITE(hw, ch, 0x0000FFFF);
 	EMU8000_PTRX_WRITE(hw, ch, 0);
 	EMU8000_CPF_WRITE(hw, ch, 0);

 	/* pitch offset */
 	EMU8000_IP_WRITE(hw, ch, rec->pitch);
 	/* set envelope parameters */
 	EMU8000_ENVVAL_WRITE(hw, ch, 0x8000);
 	EMU8000_ATKHLD_WRITE(hw, ch, 0x7f7f);
 	EMU8000_DCYSUS_WRITE(hw, ch, 0x7f7f);
 	EMU8000_ENVVOL_WRITE(hw, ch, 0x8000);
 	EMU8000_ATKHLDV_WRITE(hw, ch, 0x7f7f);
 	/* decay/sustain parameter for volume envelope is used
 	   for triggerg the voice */
 	/* modulation envelope heights */
 	EMU8000_PEFE_WRITE(hw, ch, 0x0);
 	/* lfo1/2 delay */
 	EMU8000_LFO1VAL_WRITE(hw, ch, 0x8000);
 	EMU8000_LFO2VAL_WRITE(hw, ch, 0x8000);
 	/* lfo1 pitch & cutoff shift */
 	EMU8000_FMMOD_WRITE(hw, ch, 0);
 	/* lfo1 volume & freq */
 	EMU8000_TREMFRQ_WRITE(hw, ch, 0);
 	/* lfo2 pitch & freq */
 	EMU8000_FM2FRQ2_WRITE(hw, ch, 0);
 	/* pan & loop start */
 	temp = rec->panning[ch];
 	temp = (temp <<24) | ((unsigned int)rec->loop_start[ch] - 1);
 	EMU8000_PSST_WRITE(hw, ch, temp);
 	/* chorus & loop end (chorus 8bit, MSB) */
 	temp = 0; // chorus
 	temp = (temp << 24) | ((unsigned int)rec->loop_start[ch] + rec->buf_size - 1);
 	EMU8000_CSL_WRITE(hw, ch, temp);
 	/* Q & current address (Q 4bit value, MSB) */
 	temp = 0; // filterQ
 	temp = (temp << 28) | ((unsigned int)rec->loop_start[ch] - 1);
 	EMU8000_CCCA_WRITE(hw, ch, temp);
 	/* clear unknown registers */
 	EMU8000_00A0_WRITE(hw, ch, 0);
 	EMU8000_0080_WRITE(hw, ch, 0);
 }

 /*
  * trigger the voice
  */
 static void start_voice(struct snd_emu8k_pcm *rec, int ch)
 {
 	unsigned long flags;
 	struct snd_emu8000 *hw = rec->emu;
 	unsigned int temp, aux;
 	int pt = calc_pitch_target(rec->pitch);

 	/* cutoff and volume */
 	EMU8000_IFATN_WRITE(hw, ch, 0xff00);
 	EMU8000_VTFT_WRITE(hw, ch, 0xffff);
 	EMU8000_CVCF_WRITE(hw, ch, 0xffff);
 	/* trigger envelope */
 	EMU8000_DCYSUSV_WRITE(hw, ch, 0x7f7f);
 	/* set reverb and pitch target */
 	temp = 0; // reverb
 	if (rec->panning[ch] == 0)
 		aux = 0xff;
 	else
 		aux = (-rec->panning[ch]) & 0xff;
 	temp = (temp << 8) | (pt << 16) | aux;
 	EMU8000_PTRX_WRITE(hw, ch, temp);
 	EMU8000_CPF_WRITE(hw, ch, pt << 16);

 	/* start timer */
 	spin_lock_irqsave(&rec->timer_lock, flags);
 	if (! rec->timer_running) {
 		rec->timer.expires = jiffies + 1;
 		add_timer(&rec->timer);
 		rec->timer_running = 1;
 	}
 	spin_unlock_irqrestore(&rec->timer_lock, flags);
 }

 /*
  * stop the voice immediately
  */
 static void stop_voice(struct snd_emu8k_pcm *rec, int ch)
 {
 	unsigned long flags;
 	struct snd_emu8000 *hw = rec->emu;

 	EMU8000_DCYSUSV_WRITE(hw, ch, 0x807F);

 	/* stop timer */
 	spin_lock_irqsave(&rec->timer_lock, flags);
 	if (rec->timer_running) {
 		del_timer(&rec->timer);
 		rec->timer_running = 0;
 	}
 	spin_unlock_irqrestore(&rec->timer_lock, flags);
 }

 static int emu8k_pcm_trigger(struct snd_pcm_substream *subs, int cmd)
 {
 	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
 	int ch;

 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_START:
 		for (ch = 0; ch < rec->voices; ch++)
 			start_voice(rec, ch);
 		rec->running = 1;
 		break;
 	case SNDRV_PCM_TRIGGER_STOP:
 		rec->running = 0;
 		for (ch = 0; ch < rec->voices; ch++)
 			stop_voice(rec, ch);
 		break;
 	default:
 		return -EINVAL;
 	}
 	return 0;
 }


 /*
  * copy / silence ops
  */

 /*
  * this macro should be inserted in the copy/silence loops
  * to reduce the latency.  without this, the system will hang up
  * during the whole loop.
  */
 #define CHECK_SCHEDULER() \
 do { \
 	cond_resched();\
 	if (signal_pending(current))\
 		return -EAGAIN;\
 } while (0)


 #ifdef USE_NONINTERLEAVE
 /* copy one channel block */
 static int emu8k_transfer_block(struct snd_emu8000 *emu, int offset, unsigned short *buf, int count)
 {
 	EMU8000_SMALW_WRITE(emu, offset);
 	while (count > 0) {
 		unsigned short sval;
 		CHECK_SCHEDULER();
 		get_user(sval, buf);
 		EMU8000_SMLD_WRITE(emu, sval);
 		buf++;
 		count--;
 	}
 	return 0;
 }

 static int emu8k_pcm_copy(struct snd_pcm_substream *subs,
 			  int voice,
 			  snd_pcm_uframes_t pos,
 			  void *src,
 			  snd_pcm_uframes_t count)
 {
 	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
 	struct snd_emu8000 *emu = rec->emu;

 	snd_emu8000_write_wait(emu, 1);
 	if (voice == -1) {
 		unsigned short *buf = src;
 		int i, err;
 		count /= rec->voices;
 		for (i = 0; i < rec->voices; i++) {
 			err = emu8k_transfer_block(emu, pos + rec->loop_start[i], buf, count);
 			if (err < 0)
 				return err;
 			buf += count;
 		}
 		return 0;
 	} else {
 		return emu8k_transfer_block(emu, pos + rec->loop_start[voice], src, count);
 	}
 }

 /* make a channel block silence */
 static int emu8k_silence_block(struct snd_emu8000 *emu, int offset, int count)
 {
 	EMU8000_SMALW_WRITE(emu, offset);
 	while (count > 0) {
 		CHECK_SCHEDULER();
 		EMU8000_SMLD_WRITE(emu, 0);
 		count--;
 	}
 	return 0;
 }

 static int emu8k_pcm_silence(struct snd_pcm_substream *subs,
 			     int voice,
 			     snd_pcm_uframes_t pos,
 			     snd_pcm_uframes_t count)
 {
 	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
 	struct snd_emu8000 *emu = rec->emu;

 	snd_emu8000_write_wait(emu, 1);
 	if (voice == -1 && rec->voices == 1)
 		voice = 0;
 	if (voice == -1) {
 		int err;
 		err = emu8k_silence_block(emu, pos + rec->loop_start[0], count / 2);
 		if (err < 0)
 			return err;
 		return emu8k_silence_block(emu, pos + rec->loop_start[1], count / 2);
 	} else {
 		return emu8k_silence_block(emu, pos + rec->loop_start[voice], count);
 	}
 }

 #else /* interleave */

 /*
  * copy the interleaved data can be done easily by using
  * DMA "left" and "right" channels on emu8k engine.
  */
 static int emu8k_pcm_copy(struct snd_pcm_substream *subs,
 			  int voice,
 			  snd_pcm_uframes_t pos,
 			  void __user *src,
 			  snd_pcm_uframes_t count)
 {
 	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
 	struct snd_emu8000 *emu = rec->emu;
 	unsigned short __user *buf = src;

 	snd_emu8000_write_wait(emu, 1);
 	EMU8000_SMALW_WRITE(emu, pos + rec->loop_start[0]);
 	if (rec->voices > 1)
 		EMU8000_SMARW_WRITE(emu, pos + rec->loop_start[1]);

 	while (count-- > 0) {
 		unsigned short sval;
 		CHECK_SCHEDULER();
 		get_user(sval, buf);
 		EMU8000_SMLD_WRITE(emu, sval);
 		buf++;
 		if (rec->voices > 1) {
 			CHECK_SCHEDULER();
 			get_user(sval, buf);
 			EMU8000_SMRD_WRITE(emu, sval);
 			buf++;
 		}
 	}
 	return 0;
 }

 static int emu8k_pcm_silence(struct snd_pcm_substream *subs,
 			     int voice,
 			     snd_pcm_uframes_t pos,
 			     snd_pcm_uframes_t count)
 {
 	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
 	struct snd_emu8000 *emu = rec->emu;

 	snd_emu8000_write_wait(emu, 1);
 	EMU8000_SMALW_WRITE(emu, rec->loop_start[0] + pos);
 	if (rec->voices > 1)
 		EMU8000_SMARW_WRITE(emu, rec->loop_start[1] + pos);
 	while (count-- > 0) {
 		CHECK_SCHEDULER();
 		EMU8000_SMLD_WRITE(emu, 0);
 		if (rec->voices > 1) {
 			CHECK_SCHEDULER();
 			EMU8000_SMRD_WRITE(emu, 0);
 		}
 	}
 	return 0;
 }
 #endif


 /*
  * allocate a memory block
  */
 static int emu8k_pcm_hw_params(struct snd_pcm_substream *subs,
 			       struct snd_pcm_hw_params *hw_params)
 {
 	struct snd_emu8k_pcm *rec = subs->runtime->private_data;

 	if (rec->block) {
 		/* reallocation - release the old block */
 		snd_util_mem_free(rec->emu->memhdr, rec->block);
 		rec->block = NULL;
 	}

 	rec->allocated_bytes = params_buffer_bytes(hw_params) + LOOP_BLANK_SIZE * 4;
 	rec->block = snd_util_mem_alloc(rec->emu->memhdr, rec->allocated_bytes);
 	if (! rec->block)
 		return -ENOMEM;
 	rec->offset = EMU8000_DRAM_OFFSET + (rec->block->offset >> 1); /* in word */
 	/* at least dma_bytes must be set for non-interleaved mode */
 	subs->dma_buffer.bytes = params_buffer_bytes(hw_params);

 	return 0;
 }

 /*
  * free the memory block
  */
 static int emu8k_pcm_hw_free(struct snd_pcm_substream *subs)
 {
 	struct snd_emu8k_pcm *rec = subs->runtime->private_data;

 	if (rec->block) {
 		int ch;
 		for (ch = 0; ch < rec->voices; ch++)
 			stop_voice(rec, ch); // to be sure
 		if (rec->dram_opened)
 			emu8k_close_dram(rec->emu);
 		snd_util_mem_free(rec->emu->memhdr, rec->block);
 		rec->block = NULL;
 	}
 	return 0;
 }

 /*
  */
 static int emu8k_pcm_prepare(struct snd_pcm_substream *subs)
 {
 	struct snd_emu8k_pcm *rec = subs->runtime->private_data;

 	rec->pitch = 0xe000 + calc_rate_offset(subs->runtime->rate);
 	rec->last_ptr = 0;
 	rec->period_pos = 0;

 	rec->buf_size = subs->runtime->buffer_size;
 	rec->period_size = subs->runtime->period_size;
 	rec->voices = subs->runtime->channels;
 	rec->loop_start[0] = rec->offset + LOOP_BLANK_SIZE;
 	if (rec->voices > 1)
 		rec->loop_start[1] = rec->loop_start[0] + rec->buf_size + LOOP_BLANK_SIZE;
 	if (rec->voices > 1) {
 		rec->panning[0] = 0xff;
 		rec->panning[1] = 0x00;
 	} else
 		rec->panning[0] = 0x80;

 	if (! rec->dram_opened) {
 		int err, i, ch;

 		snd_emux_terminate_all(rec->emu->emu);
 		if ((err = emu8k_open_dram_for_pcm(rec->emu, rec->voices)) != 0)
 			return err;
 		rec->dram_opened = 1;

 		/* clear loop blanks */
 		snd_emu8000_write_wait(rec->emu, 0);
 		EMU8000_SMALW_WRITE(rec->emu, rec->offset);
 		for (i = 0; i < LOOP_BLANK_SIZE; i++)
 			EMU8000_SMLD_WRITE(rec->emu, 0);
 		for (ch = 0; ch < rec->voices; ch++) {
 			EMU8000_SMALW_WRITE(rec->emu, rec->loop_start[ch] + rec->buf_size);
 			for (i = 0; i < LOOP_BLANK_SIZE; i++)
 				EMU8000_SMLD_WRITE(rec->emu, 0);
 		}
 	}

 	setup_voice(rec, 0);
 	if (rec->voices > 1)
 		setup_voice(rec, 1);
 	return 0;
 }

 static snd_pcm_uframes_t emu8k_pcm_pointer(struct snd_pcm_substream *subs)
 {
 	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
 	if (rec->running)
 		return emu8k_get_curpos(rec, 0);
 	return 0;
 }


 static struct snd_pcm_ops emu8k_pcm_ops = {
 	.open =		emu8k_pcm_open,
 	.close =	emu8k_pcm_close,
 	.ioctl =	snd_pcm_lib_ioctl,
 	.hw_params =	emu8k_pcm_hw_params,
 	.hw_free =	emu8k_pcm_hw_free,
 	.prepare =	emu8k_pcm_prepare,
 	.trigger =	emu8k_pcm_trigger,
 	.pointer =	emu8k_pcm_pointer,
 	.copy =		emu8k_pcm_copy,
 	.silence =	emu8k_pcm_silence,
 };


 static void snd_emu8000_pcm_free(struct snd_pcm *pcm)
 {
 	struct snd_emu8000 *emu = pcm->private_data;
 	emu->pcm = NULL;
 }

 int snd_emu8000_pcm_new(struct snd_card *card, struct snd_emu8000 *emu, int index)
 {
 	struct snd_pcm *pcm;
 	int err;

 	if ((err = snd_pcm_new(card, "Emu8000 PCM", index, 1, 0, &pcm)) < 0)
 		return err;
 	pcm->private_data = emu;
 	pcm->private_free = snd_emu8000_pcm_free;
 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &emu8k_pcm_ops);
 	emu->pcm = pcm;

 	snd_device_register(card, pcm);

 	return 0;
 }
	/*
	* pcm emulation on emu8000 wavetable
	*
	* Copyright (C) 2002 Takashi Iwai <tiwai@suse.de>
	*
	* 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
	*/

	#include "emu8000_local.h"
	#include <linux/init.h>
	#include <linux/slab.h>
	#include <sound/initval.h>
	#include <sound/pcm.h>

	/*
	* define the following if you want to use this pcm with non-interleaved mode
	*/
	/* #define USE_NONINTERLEAVE */

	/* NOTE: for using the non-interleaved mode with alsa-lib, you have to set
	* mmap_emulation flag to 1 in your .asoundrc, such like
	*
	* pcm.emu8k {
	* type plug
	* slave.pcm {
	* type hw
	* card 0
	* device 1
	* mmap_emulation 1
	* }
	* }
	*
	* besides, for the time being, the non-interleaved mode doesn't work well on
	* alsa-lib...
	*/


	struct snd_emu8k_pcm {
	struct snd_emu8000 *emu;
	struct snd_pcm_substream *substream;

	unsigned int allocated_bytes;
	struct snd_util_memblk *block;
	unsigned int offset;
	unsigned int buf_size;
	unsigned int period_size;
	unsigned int loop_start[2];
	unsigned int pitch;
	int panning[2];
	int last_ptr;
	int period_pos;
	int voices;
	unsigned int dram_opened: 1;
	unsigned int running: 1;
	unsigned int timer_running: 1;
	struct timer_list timer;
	spinlock_t timer_lock;
	};

	#define LOOP_BLANK_SIZE 8


	/*
	* open up channels for the simultaneous data transfer and playback
	*/
	static int
	emu8k_open_dram_for_pcm(struct snd_emu8000 *emu, int channels)
	{
	int i;

	/* reserve up to 2 voices for playback */
	snd_emux_lock_voice(emu->emu, 0);
	if (channels > 1)
	snd_emux_lock_voice(emu->emu, 1);

	/* reserve 28 voices for loading */
	for (i = channels + 1; i < EMU8000_DRAM_VOICES; i++) {
	unsigned int mode = EMU8000_RAM_WRITE;
	snd_emux_lock_voice(emu->emu, i);
	#ifndef USE_NONINTERLEAVE
	if (channels > 1 && (i & 1) != 0)
	mode \|= EMU8000_RAM_RIGHT;
	#endif
	snd_emu8000_dma_chan(emu, i, mode);
	}

	/* assign voice 31 and 32 to ROM */
	EMU8000_VTFT_WRITE(emu, 30, 0);
	EMU8000_PSST_WRITE(emu, 30, 0x1d8);
	EMU8000_CSL_WRITE(emu, 30, 0x1e0);
	EMU8000_CCCA_WRITE(emu, 30, 0x1d8);
	EMU8000_VTFT_WRITE(emu, 31, 0);
	EMU8000_PSST_WRITE(emu, 31, 0x1d8);
	EMU8000_CSL_WRITE(emu, 31, 0x1e0);
	EMU8000_CCCA_WRITE(emu, 31, 0x1d8);

	return 0;
	}

	/*
	*/
	static void
	snd_emu8000_write_wait(struct snd_emu8000 *emu, int can_schedule)
	{
	while ((EMU8000_SMALW_READ(emu) & 0x80000000) != 0) {
	if (can_schedule) {
	schedule_timeout_interruptible(1);
	if (signal_pending(current))
	break;
	}
	}
	}

	/*
	* close all channels
	*/
	static void
	emu8k_close_dram(struct snd_emu8000 *emu)
	{
	int i;

	for (i = 0; i < 2; i++)
	snd_emux_unlock_voice(emu->emu, i);
	for (; i < EMU8000_DRAM_VOICES; i++) {
	snd_emu8000_dma_chan(emu, i, EMU8000_RAM_CLOSE);
	snd_emux_unlock_voice(emu->emu, i);
	}
	}

	/*
	* convert Hz to AWE32 rate offset (see emux/soundfont.c)
	*/

	#define OFFSET_SAMPLERATE 1011119 /* base = 44100 */
	#define SAMPLERATE_RATIO 4096

	static int calc_rate_offset(int hz)
	{
	return snd_sf_linear_to_log(hz, OFFSET_SAMPLERATE, SAMPLERATE_RATIO);
	}


	/*
	*/

	static struct snd_pcm_hardware emu8k_pcm_hw = {
	#ifdef USE_NONINTERLEAVE
	.info = SNDRV_PCM_INFO_NONINTERLEAVED,
	#else
	.info = SNDRV_PCM_INFO_INTERLEAVED,
	#endif
	.formats = SNDRV_PCM_FMTBIT_S16_LE,
	.rates = SNDRV_PCM_RATE_CONTINUOUS \| SNDRV_PCM_RATE_8000_48000,
	.rate_min = 4000,
	.rate_max = 48000,
	.channels_min = 1,
	.channels_max = 2,
	.buffer_bytes_max = (128*1024),
	.period_bytes_min = 1024,
	.period_bytes_max = (128*1024),
	.periods_min = 2,
	.periods_max = 1024,
	.fifo_size = 0,

	};

	/*
	* get the current position at the given channel from CCCA register
	*/
	static inline int emu8k_get_curpos(struct snd_emu8k_pcm *rec, int ch)
	{
	int val = EMU8000_CCCA_READ(rec->emu, ch) & 0xfffffff;
	val -= rec->loop_start[ch] - 1;
	return val;
	}


	/*
	* timer interrupt handler
	* check the current position and update the period if necessary.
	*/
	static void emu8k_pcm_timer_func(unsigned long data)
	{
	struct snd_emu8k_pcm rec = (struct snd_emu8k_pcm )data;
	int ptr, delta;

	spin_lock(&rec->timer_lock);
	/* update the current pointer */
	ptr = emu8k_get_curpos(rec, 0);
	if (ptr < rec->last_ptr)
	delta = ptr + rec->buf_size - rec->last_ptr;
	else
	delta = ptr - rec->last_ptr;
	rec->period_pos += delta;
	rec->last_ptr = ptr;

	/* reprogram timer */
	rec->timer.expires = jiffies + 1;
	add_timer(&rec->timer);

	/* update period */
	if (rec->period_pos >= (int)rec->period_size) {
	rec->period_pos %= rec->period_size;
	spin_unlock(&rec->timer_lock);
	snd_pcm_period_elapsed(rec->substream);
	return;
	}
	spin_unlock(&rec->timer_lock);
	}


	/*
	* open pcm
	* creating an instance here
	*/
	static int emu8k_pcm_open(struct snd_pcm_substream *subs)
	{
	struct snd_emu8000 *emu = snd_pcm_substream_chip(subs);
	struct snd_emu8k_pcm *rec;
	struct snd_pcm_runtime *runtime = subs->runtime;

	rec = kzalloc(sizeof(*rec), GFP_KERNEL);
	if (! rec)
	return -ENOMEM;

	rec->emu = emu;
	rec->substream = subs;
	runtime->private_data = rec;

	spin_lock_init(&rec->timer_lock);
	init_timer(&rec->timer);
	rec->timer.function = emu8k_pcm_timer_func;
	rec->timer.data = (unsigned long)rec;

	runtime->hw = emu8k_pcm_hw;
	runtime->hw.buffer_bytes_max = emu->mem_size - LOOP_BLANK_SIZE * 3;
	runtime->hw.period_bytes_max = runtime->hw.buffer_bytes_max / 2;

	/* use timer to update periods.. (specified in msec) */
	snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_PERIOD_TIME,
	(1000000 + HZ - 1) / HZ, UINT_MAX);

	return 0;
	}

	static int emu8k_pcm_close(struct snd_pcm_substream *subs)
	{
	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
	kfree(rec);
	subs->runtime->private_data = NULL;
	return 0;
	}

	/*
	* calculate pitch target
	*/
	static int calc_pitch_target(int pitch)
	{
	int ptarget = 1 << (pitch >> 12);
	if (pitch & 0x800) ptarget += (ptarget * 0x102e) / 0x2710;
	if (pitch & 0x400) ptarget += (ptarget * 0x764) / 0x2710;
	if (pitch & 0x200) ptarget += (ptarget * 0x389) / 0x2710;
	ptarget += (ptarget >> 1);
	if (ptarget > 0xffff) ptarget = 0xffff;
	return ptarget;
	}

	/*
	* set up the voice
	*/
	static void setup_voice(struct snd_emu8k_pcm *rec, int ch)
	{
	struct snd_emu8000 *hw = rec->emu;
	unsigned int temp;

	/* channel to be silent and idle */
	EMU8000_DCYSUSV_WRITE(hw, ch, 0x0080);
	EMU8000_VTFT_WRITE(hw, ch, 0x0000FFFF);
	EMU8000_CVCF_WRITE(hw, ch, 0x0000FFFF);
	EMU8000_PTRX_WRITE(hw, ch, 0);
	EMU8000_CPF_WRITE(hw, ch, 0);

	/* pitch offset */
	EMU8000_IP_WRITE(hw, ch, rec->pitch);
	/* set envelope parameters */
	EMU8000_ENVVAL_WRITE(hw, ch, 0x8000);
	EMU8000_ATKHLD_WRITE(hw, ch, 0x7f7f);
	EMU8000_DCYSUS_WRITE(hw, ch, 0x7f7f);
	EMU8000_ENVVOL_WRITE(hw, ch, 0x8000);
	EMU8000_ATKHLDV_WRITE(hw, ch, 0x7f7f);
	/* decay/sustain parameter for volume envelope is used
	for triggerg the voice */
	/* modulation envelope heights */
	EMU8000_PEFE_WRITE(hw, ch, 0x0);
	/* lfo1/2 delay */
	EMU8000_LFO1VAL_WRITE(hw, ch, 0x8000);
	EMU8000_LFO2VAL_WRITE(hw, ch, 0x8000);
	/* lfo1 pitch & cutoff shift */
	EMU8000_FMMOD_WRITE(hw, ch, 0);
	/* lfo1 volume & freq */
	EMU8000_TREMFRQ_WRITE(hw, ch, 0);
	/* lfo2 pitch & freq */
	EMU8000_FM2FRQ2_WRITE(hw, ch, 0);
	/* pan & loop start */
	temp = rec->panning[ch];
	temp = (temp <<24) \| ((unsigned int)rec->loop_start[ch] - 1);
	EMU8000_PSST_WRITE(hw, ch, temp);
	/* chorus & loop end (chorus 8bit, MSB) */
	temp = 0; // chorus
	temp = (temp << 24) \| ((unsigned int)rec->loop_start[ch] + rec->buf_size - 1);
	EMU8000_CSL_WRITE(hw, ch, temp);
	/* Q & current address (Q 4bit value, MSB) */
	temp = 0; // filterQ
	temp = (temp << 28) \| ((unsigned int)rec->loop_start[ch] - 1);
	EMU8000_CCCA_WRITE(hw, ch, temp);
	/* clear unknown registers */
	EMU8000_00A0_WRITE(hw, ch, 0);
	EMU8000_0080_WRITE(hw, ch, 0);
	}

	/*
	* trigger the voice
	*/
	static void start_voice(struct snd_emu8k_pcm *rec, int ch)
	{
	unsigned long flags;
	struct snd_emu8000 *hw = rec->emu;
	unsigned int temp, aux;
	int pt = calc_pitch_target(rec->pitch);

	/* cutoff and volume */
	EMU8000_IFATN_WRITE(hw, ch, 0xff00);
	EMU8000_VTFT_WRITE(hw, ch, 0xffff);
	EMU8000_CVCF_WRITE(hw, ch, 0xffff);
	/* trigger envelope */
	EMU8000_DCYSUSV_WRITE(hw, ch, 0x7f7f);
	/* set reverb and pitch target */
	temp = 0; // reverb
	if (rec->panning[ch] == 0)
	aux = 0xff;
	else
	aux = (-rec->panning[ch]) & 0xff;
	temp = (temp << 8) \| (pt << 16) \| aux;
	EMU8000_PTRX_WRITE(hw, ch, temp);
	EMU8000_CPF_WRITE(hw, ch, pt << 16);

	/* start timer */
	spin_lock_irqsave(&rec->timer_lock, flags);
	if (! rec->timer_running) {
	rec->timer.expires = jiffies + 1;
	add_timer(&rec->timer);
	rec->timer_running = 1;
	}
	spin_unlock_irqrestore(&rec->timer_lock, flags);
	}

	/*
	* stop the voice immediately
	*/
	static void stop_voice(struct snd_emu8k_pcm *rec, int ch)
	{
	unsigned long flags;
	struct snd_emu8000 *hw = rec->emu;

	EMU8000_DCYSUSV_WRITE(hw, ch, 0x807F);

	/* stop timer */
	spin_lock_irqsave(&rec->timer_lock, flags);
	if (rec->timer_running) {
	del_timer(&rec->timer);
	rec->timer_running = 0;
	}
	spin_unlock_irqrestore(&rec->timer_lock, flags);
	}

	static int emu8k_pcm_trigger(struct snd_pcm_substream *subs, int cmd)
	{
	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
	int ch;

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
	for (ch = 0; ch < rec->voices; ch++)
	start_voice(rec, ch);
	rec->running = 1;
	break;
	case SNDRV_PCM_TRIGGER_STOP:
	rec->running = 0;
	for (ch = 0; ch < rec->voices; ch++)
	stop_voice(rec, ch);
	break;
	default:
	return -EINVAL;
	}
	return 0;
	}


	/*
	* copy / silence ops
	*/

	/*
	* this macro should be inserted in the copy/silence loops
	* to reduce the latency. without this, the system will hang up
	* during the whole loop.
	*/
	#define CHECK_SCHEDULER() \
	do { \
	cond_resched();\
	if (signal_pending(current))\
	return -EAGAIN;\
	} while (0)


	#ifdef USE_NONINTERLEAVE
	/* copy one channel block */
	static int emu8k_transfer_block(struct snd_emu8000 emu, int offset, unsigned short buf, int count)
	{
	EMU8000_SMALW_WRITE(emu, offset);
	while (count > 0) {
	unsigned short sval;
	CHECK_SCHEDULER();
	get_user(sval, buf);
	EMU8000_SMLD_WRITE(emu, sval);
	buf++;
	count--;
	}
	return 0;
	}

	static int emu8k_pcm_copy(struct snd_pcm_substream *subs,
	int voice,
	snd_pcm_uframes_t pos,
	void *src,
	snd_pcm_uframes_t count)
	{
	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
	struct snd_emu8000 *emu = rec->emu;

	snd_emu8000_write_wait(emu, 1);
	if (voice == -1) {
	unsigned short *buf = src;
	int i, err;
	count /= rec->voices;
	for (i = 0; i < rec->voices; i++) {
	err = emu8k_transfer_block(emu, pos + rec->loop_start[i], buf, count);
	if (err < 0)
	return err;
	buf += count;
	}
	return 0;
	} else {
	return emu8k_transfer_block(emu, pos + rec->loop_start[voice], src, count);
	}
	}

	/* make a channel block silence */
	static int emu8k_silence_block(struct snd_emu8000 *emu, int offset, int count)
	{
	EMU8000_SMALW_WRITE(emu, offset);
	while (count > 0) {
	CHECK_SCHEDULER();
	EMU8000_SMLD_WRITE(emu, 0);
	count--;
	}
	return 0;
	}

	static int emu8k_pcm_silence(struct snd_pcm_substream *subs,
	int voice,
	snd_pcm_uframes_t pos,
	snd_pcm_uframes_t count)
	{
	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
	struct snd_emu8000 *emu = rec->emu;

	snd_emu8000_write_wait(emu, 1);
	if (voice == -1 && rec->voices == 1)
	voice = 0;
	if (voice == -1) {
	int err;
	err = emu8k_silence_block(emu, pos + rec->loop_start[0], count / 2);
	if (err < 0)
	return err;
	return emu8k_silence_block(emu, pos + rec->loop_start[1], count / 2);
	} else {
	return emu8k_silence_block(emu, pos + rec->loop_start[voice], count);
	}
	}

	#else /* interleave */

	/*
	* copy the interleaved data can be done easily by using
	* DMA "left" and "right" channels on emu8k engine.
	*/
	static int emu8k_pcm_copy(struct snd_pcm_substream *subs,
	int voice,
	snd_pcm_uframes_t pos,
	void __user *src,
	snd_pcm_uframes_t count)
	{
	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
	struct snd_emu8000 *emu = rec->emu;
	unsigned short __user *buf = src;

	snd_emu8000_write_wait(emu, 1);
	EMU8000_SMALW_WRITE(emu, pos + rec->loop_start[0]);
	if (rec->voices > 1)
	EMU8000_SMARW_WRITE(emu, pos + rec->loop_start[1]);

	while (count-- > 0) {
	unsigned short sval;
	CHECK_SCHEDULER();
	get_user(sval, buf);
	EMU8000_SMLD_WRITE(emu, sval);
	buf++;
	if (rec->voices > 1) {
	CHECK_SCHEDULER();
	get_user(sval, buf);
	EMU8000_SMRD_WRITE(emu, sval);
	buf++;
	}
	}
	return 0;
	}

	static int emu8k_pcm_silence(struct snd_pcm_substream *subs,
	int voice,
	snd_pcm_uframes_t pos,
	snd_pcm_uframes_t count)
	{
	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
	struct snd_emu8000 *emu = rec->emu;

	snd_emu8000_write_wait(emu, 1);
	EMU8000_SMALW_WRITE(emu, rec->loop_start[0] + pos);
	if (rec->voices > 1)
	EMU8000_SMARW_WRITE(emu, rec->loop_start[1] + pos);
	while (count-- > 0) {
	CHECK_SCHEDULER();
	EMU8000_SMLD_WRITE(emu, 0);
	if (rec->voices > 1) {
	CHECK_SCHEDULER();
	EMU8000_SMRD_WRITE(emu, 0);
	}
	}
	return 0;
	}
	#endif


	/*
	* allocate a memory block
	*/
	static int emu8k_pcm_hw_params(struct snd_pcm_substream *subs,
	struct snd_pcm_hw_params *hw_params)
	{
	struct snd_emu8k_pcm *rec = subs->runtime->private_data;

	if (rec->block) {
	/* reallocation - release the old block */
	snd_util_mem_free(rec->emu->memhdr, rec->block);
	rec->block = NULL;
	}

	rec->allocated_bytes = params_buffer_bytes(hw_params) + LOOP_BLANK_SIZE * 4;
	rec->block = snd_util_mem_alloc(rec->emu->memhdr, rec->allocated_bytes);
	if (! rec->block)
	return -ENOMEM;
	rec->offset = EMU8000_DRAM_OFFSET + (rec->block->offset >> 1); /* in word */
	/* at least dma_bytes must be set for non-interleaved mode */
	subs->dma_buffer.bytes = params_buffer_bytes(hw_params);

	return 0;
	}

	/*
	* free the memory block
	*/
	static int emu8k_pcm_hw_free(struct snd_pcm_substream *subs)
	{
	struct snd_emu8k_pcm *rec = subs->runtime->private_data;

	if (rec->block) {
	int ch;
	for (ch = 0; ch < rec->voices; ch++)
	stop_voice(rec, ch); // to be sure
	if (rec->dram_opened)
	emu8k_close_dram(rec->emu);
	snd_util_mem_free(rec->emu->memhdr, rec->block);
	rec->block = NULL;
	}
	return 0;
	}

	/*
	*/
	static int emu8k_pcm_prepare(struct snd_pcm_substream *subs)
	{
	struct snd_emu8k_pcm *rec = subs->runtime->private_data;

	rec->pitch = 0xe000 + calc_rate_offset(subs->runtime->rate);
	rec->last_ptr = 0;
	rec->period_pos = 0;

	rec->buf_size = subs->runtime->buffer_size;
	rec->period_size = subs->runtime->period_size;
	rec->voices = subs->runtime->channels;
	rec->loop_start[0] = rec->offset + LOOP_BLANK_SIZE;
	if (rec->voices > 1)
	rec->loop_start[1] = rec->loop_start[0] + rec->buf_size + LOOP_BLANK_SIZE;
	if (rec->voices > 1) {
	rec->panning[0] = 0xff;
	rec->panning[1] = 0x00;
	} else
	rec->panning[0] = 0x80;

	if (! rec->dram_opened) {
	int err, i, ch;

	snd_emux_terminate_all(rec->emu->emu);
	if ((err = emu8k_open_dram_for_pcm(rec->emu, rec->voices)) != 0)
	return err;
	rec->dram_opened = 1;

	/* clear loop blanks */
	snd_emu8000_write_wait(rec->emu, 0);
	EMU8000_SMALW_WRITE(rec->emu, rec->offset);
	for (i = 0; i < LOOP_BLANK_SIZE; i++)
	EMU8000_SMLD_WRITE(rec->emu, 0);
	for (ch = 0; ch < rec->voices; ch++) {
	EMU8000_SMALW_WRITE(rec->emu, rec->loop_start[ch] + rec->buf_size);
	for (i = 0; i < LOOP_BLANK_SIZE; i++)
	EMU8000_SMLD_WRITE(rec->emu, 0);
	}
	}

	setup_voice(rec, 0);
	if (rec->voices > 1)
	setup_voice(rec, 1);
	return 0;
	}

	static snd_pcm_uframes_t emu8k_pcm_pointer(struct snd_pcm_substream *subs)
	{
	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
	if (rec->running)
	return emu8k_get_curpos(rec, 0);
	return 0;
	}


	static struct snd_pcm_ops emu8k_pcm_ops = {
	.open = emu8k_pcm_open,
	.close = emu8k_pcm_close,
	.ioctl = snd_pcm_lib_ioctl,
	.hw_params = emu8k_pcm_hw_params,
	.hw_free = emu8k_pcm_hw_free,
	.prepare = emu8k_pcm_prepare,
	.trigger = emu8k_pcm_trigger,
	.pointer = emu8k_pcm_pointer,
	.copy = emu8k_pcm_copy,
	.silence = emu8k_pcm_silence,
	};


	static void snd_emu8000_pcm_free(struct snd_pcm *pcm)
	{
	struct snd_emu8000 *emu = pcm->private_data;
	emu->pcm = NULL;
	}

	int snd_emu8000_pcm_new(struct snd_card card, struct snd_emu8000 emu, int index)
	{
	struct snd_pcm *pcm;
	int err;

	if ((err = snd_pcm_new(card, "Emu8000 PCM", index, 1, 0, &pcm)) < 0)
	return err;
	pcm->private_data = emu;
	pcm->private_free = snd_emu8000_pcm_free;
	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &emu8k_pcm_ops);
	emu->pcm = pcm;

	snd_device_register(card, pcm);

	return 0;
	}