/*
   *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
   *                   Creative Labs, Inc.
   *                   Lee Revell <rlrevell@joe-job.com>
   *  Routines for control of EMU10K1 chips - voice manager
   *
   *  Rewrote voice allocator for multichannel support - rlrevell 12/2004
   * 
   *  BUGS:
   *    --
   *
   *  TODO:
   *    --
   *
   *   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 <linux/time.h>
  #include <linux/export.h>
  #include <sound/core.h>
  #include <sound/emu10k1.h>
  
  /* Previously the voice allocator started at 0 every time.  The new voice 
   * allocator uses a round robin scheme.  The next free voice is tracked in 
   * the card record and each allocation begins where the last left off.  The 
   * hardware requires stereo interleaved voices be aligned to an even/odd 
   * boundary.  For multichannel voice allocation we ensure than the block of 
   * voices does not cross the 32 voice boundary.  This simplifies the 
   * multichannel support and ensures we can use a single write to the 
   * (set|clear)_loop_stop registers.  Otherwise (for example) the voices would 
   * get out of sync when pausing/resuming a stream.
   *							--rlrevell
   */
  
  static int voice_alloc(struct snd_emu10k1 *emu, int type, int number,
  		       struct snd_emu10k1_voice **rvoice)
  {
  	struct snd_emu10k1_voice *voice;
  	int i, j, k, first_voice, last_voice, skip;
  
  	*rvoice = NULL;
  	first_voice = last_voice = 0;
  	for (i = emu->next_free_voice, j = 0; j < NUM_G ; i += number, j += number) {
  		/*
  		printk(KERN_DEBUG "i %d j %d next free %d!
  ",
  		       i, j, emu->next_free_voice);
  		*/
  		i %= NUM_G;
  
  		/* stereo voices must be even/odd */
  		if ((number == 2) && (i % 2)) {
  			i++;
  			continue;
  		}
  			
  		skip = 0;
  		for (k = 0; k < number; k++) {
  			voice = &emu->voices[(i+k) % NUM_G];
  			if (voice->use) {
  				skip = 1;
  				break;
  			}
  		}
  		if (!skip) {
  			/* printk(KERN_DEBUG "allocated voice %d
  ", i); */
  			first_voice = i;
  			last_voice = (i + number) % NUM_G;
  			emu->next_free_voice = last_voice;
  			break;
  		}
  	}
  	
  	if (first_voice == last_voice)
  		return -ENOMEM;
  	
  	for (i = 0; i < number; i++) {
  		voice = &emu->voices[(first_voice + i) % NUM_G];
  		/*
  		printk(kERN_DEBUG "voice alloc - %i, %i of %i
  ",
  		       voice->number, idx-first_voice+1, number);
  		*/
  		voice->use = 1;
  		switch (type) {
  		case EMU10K1_PCM:
  			voice->pcm = 1;
  			break;
  		case EMU10K1_SYNTH:
  			voice->synth = 1;
  			break;
  		case EMU10K1_MIDI:
  			voice->midi = 1;
  			break;
  		case EMU10K1_EFX:
  			voice->efx = 1;
  			break;
  		}
  	}
  	*rvoice = &emu->voices[first_voice];
  	return 0;
  }
  
  int snd_emu10k1_voice_alloc(struct snd_emu10k1 *emu, int type, int number,
  			    struct snd_emu10k1_voice **rvoice)
  {
  	unsigned long flags;
  	int result;
  
  	if (snd_BUG_ON(!rvoice))
  		return -EINVAL;
  	if (snd_BUG_ON(!number))
  		return -EINVAL;
  
  	spin_lock_irqsave(&emu->voice_lock, flags);
  	for (;;) {
  		result = voice_alloc(emu, type, number, rvoice);
  		if (result == 0 || type == EMU10K1_SYNTH || type == EMU10K1_MIDI)
  			break;
  
  		/* free a voice from synth */
  		if (emu->get_synth_voice) {
  			result = emu->get_synth_voice(emu);
  			if (result >= 0) {
  				struct snd_emu10k1_voice *pvoice = &emu->voices[result];
  				pvoice->interrupt = NULL;
  				pvoice->use = pvoice->pcm = pvoice->synth = pvoice->midi = pvoice->efx = 0;
  				pvoice->epcm = NULL;
  			}
  		}
  		if (result < 0)
  			break;
  	}
  	spin_unlock_irqrestore(&emu->voice_lock, flags);
  
  	return result;
  }
  
  EXPORT_SYMBOL(snd_emu10k1_voice_alloc);
  
  int snd_emu10k1_voice_free(struct snd_emu10k1 *emu,
  			   struct snd_emu10k1_voice *pvoice)
  {
  	unsigned long flags;
  
  	if (snd_BUG_ON(!pvoice))
  		return -EINVAL;
  	spin_lock_irqsave(&emu->voice_lock, flags);
  	pvoice->interrupt = NULL;
  	pvoice->use = pvoice->pcm = pvoice->synth = pvoice->midi = pvoice->efx = 0;
  	pvoice->epcm = NULL;
  	snd_emu10k1_voice_init(emu, pvoice->number);
  	spin_unlock_irqrestore(&emu->voice_lock, flags);
  	return 0;
  }
  
  EXPORT_SYMBOL(snd_emu10k1_voice_free);