/*
   * sound/oss/sh_dac_audio.c
   *
   * SH DAC based sound :(
   *
   *  Copyright (C) 2004,2005  Andriy Skulysh
   *
   * This file is subject to the terms and conditions of the GNU General Public
   * License.  See the file "COPYING" in the main directory of this archive
   * for more details.
   */

  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/sched.h>

  #include <linux/linkage.h>
  #include <linux/slab.h>
  #include <linux/fs.h>
  #include <linux/sound.h>
  #include <linux/soundcard.h>

  #include <linux/interrupt.h>

  #include <asm/io.h>
  #include <asm/uaccess.h>
  #include <asm/irq.h>
  #include <asm/delay.h>

  #include <asm/clock.h>

  #include <asm/cpu/dac.h>

  #include <asm/cpu/timer.h>

  #include <asm/machvec.h>

  #include <asm/hp6xx.h>

  #include <asm/hd64461.h>

  
  #define MODNAME "sh_dac_audio"
  
  #define TMU_TOCR_INIT	0x00
  
  #define TMU1_TCR_INIT	0x0020	/* Clock/4, rising edge; interrupt on */
  #define TMU1_TSTR_INIT  0x02	/* Bit to turn on TMU1 */

  #define BUFFER_SIZE 48000
  
  static int rate;
  static int empty;
  static char *data_buffer, *buffer_begin, *buffer_end;
  static int in_use, device_major;
  
  static void dac_audio_start_timer(void)
  {
  	u8 tstr;
  
  	tstr = ctrl_inb(TMU_TSTR);
  	tstr |= TMU1_TSTR_INIT;
  	ctrl_outb(tstr, TMU_TSTR);
  }
  
  static void dac_audio_stop_timer(void)
  {
  	u8 tstr;
  
  	tstr = ctrl_inb(TMU_TSTR);
  	tstr &= ~TMU1_TSTR_INIT;
  	ctrl_outb(tstr, TMU_TSTR);
  }
  
  static void dac_audio_reset(void)
  {
  	dac_audio_stop_timer();
  	buffer_begin = buffer_end = data_buffer;
  	empty = 1;
  }
  
  static void dac_audio_sync(void)
  {
  	while (!empty)
  		schedule();
  }
  
  static void dac_audio_start(void)
  {

  	if (mach_is_hp6xx()) {
  		u16 v = inw(HD64461_GPADR);
  		v &= ~HD64461_GPADR_SPEAKER;
  		outw(v, HD64461_GPADR);
  	}

  	sh_dac_enable(CONFIG_SOUND_SH_DAC_AUDIO_CHANNEL);
  	ctrl_outw(TMU1_TCR_INIT, TMU1_TCR);
  }
  static void dac_audio_stop(void)
  {

  	dac_audio_stop_timer();

  
  	if (mach_is_hp6xx()) {
  		u16 v = inw(HD64461_GPADR);
  		v |= HD64461_GPADR_SPEAKER;
  		outw(v, HD64461_GPADR);
  	}

   	sh_dac_output(0, CONFIG_SOUND_SH_DAC_AUDIO_CHANNEL);

  	sh_dac_disable(CONFIG_SOUND_SH_DAC_AUDIO_CHANNEL);
  }
  
  static void dac_audio_set_rate(void)
  {
  	unsigned long interval;

   	struct clk *clk;

   	clk = clk_get(NULL, "module_clk");

   	interval = (clk_get_rate(clk) / 4) / rate;
   	clk_put(clk);

  	ctrl_outl(interval, TMU1_TCOR);
  	ctrl_outl(interval, TMU1_TCNT);
  }
  
  static int dac_audio_ioctl(struct inode *inode, struct file *file,
  			   unsigned int cmd, unsigned long arg)
  {
  	int val;
  
  	switch (cmd) {
  	case OSS_GETVERSION:
  		return put_user(SOUND_VERSION, (int *)arg);
  
  	case SNDCTL_DSP_SYNC:
  		dac_audio_sync();
  		return 0;
  
  	case SNDCTL_DSP_RESET:
  		dac_audio_reset();
  		return 0;
  
  	case SNDCTL_DSP_GETFMTS:
  		return put_user(AFMT_U8, (int *)arg);
  
  	case SNDCTL_DSP_SETFMT:
  		return put_user(AFMT_U8, (int *)arg);
  
  	case SNDCTL_DSP_NONBLOCK:
  		file->f_flags |= O_NONBLOCK;
  		return 0;
  
  	case SNDCTL_DSP_GETCAPS:
  		return 0;
  
  	case SOUND_PCM_WRITE_RATE:
  		val = *(int *)arg;
  		if (val > 0) {
  			rate = val;
  			dac_audio_set_rate();
  		}
  		return put_user(rate, (int *)arg);
  
  	case SNDCTL_DSP_STEREO:
  		return put_user(0, (int *)arg);
  
  	case SOUND_PCM_WRITE_CHANNELS:
  		return put_user(1, (int *)arg);
  
  	case SNDCTL_DSP_SETDUPLEX:
  		return -EINVAL;
  
  	case SNDCTL_DSP_PROFILE:
  		return -EINVAL;
  
  	case SNDCTL_DSP_GETBLKSIZE:
  		return put_user(BUFFER_SIZE, (int *)arg);
  
  	case SNDCTL_DSP_SETFRAGMENT:
  		return 0;
  
  	default:
  		printk(KERN_ERR "sh_dac_audio: unimplemented ioctl=0x%x
  ",
  		       cmd);
  		return -EINVAL;
  	}
  	return -EINVAL;
  }
  
  static ssize_t dac_audio_write(struct file *file, const char *buf, size_t count,
  			       loff_t * ppos)
  {
  	int free;
  	int nbytes;
  
  	if (count < 0)
  		return -EINVAL;
  
  	if (!count) {
  		dac_audio_sync();
  		return 0;
  	}
  
  	free = buffer_begin - buffer_end;
  
  	if (free < 0)
  		free += BUFFER_SIZE;
  	if ((free == 0) && (empty))
  		free = BUFFER_SIZE;
  	if (count > free)
  		count = free;
  	if (buffer_begin > buffer_end) {
  		if (copy_from_user((void *)buffer_end, buf, count))
  			return -EFAULT;
  
  		buffer_end += count;
  	} else {
  		nbytes = data_buffer + BUFFER_SIZE - buffer_end;
  		if (nbytes > count) {
  			if (copy_from_user((void *)buffer_end, buf, count))
  				return -EFAULT;
  			buffer_end += count;
  		} else {
  			if (copy_from_user((void *)buffer_end, buf, nbytes))
  				return -EFAULT;
  			if (copy_from_user
  			    ((void *)data_buffer, buf + nbytes, count - nbytes))
  				return -EFAULT;
  			buffer_end = data_buffer + count - nbytes;
  		}
  	}
  
  	if (empty) {
  		empty = 0;
  		dac_audio_start_timer();
  	}
  
  	return count;
  }
  
  static ssize_t dac_audio_read(struct file *file, char *buf, size_t count,
  			      loff_t * ppos)
  {
  	return -EINVAL;
  }
  
  static int dac_audio_open(struct inode *inode, struct file *file)
  {
  	if (file->f_mode & FMODE_READ)
  		return -ENODEV;
  	if (in_use)
  		return -EBUSY;
  
  	in_use = 1;
  
  	dac_audio_start();
  
  	return 0;
  }
  
  static int dac_audio_release(struct inode *inode, struct file *file)
  {
  	dac_audio_sync();
  	dac_audio_stop();
  	in_use = 0;
  
  	return 0;
  }

  const struct file_operations dac_audio_fops = {

        .read =		dac_audio_read,
        .write =	dac_audio_write,
        .ioctl =	dac_audio_ioctl,
        .open =		dac_audio_open,
        .release =	dac_audio_release,
  };

  static irqreturn_t timer1_interrupt(int irq, void *dev)

  {
  	unsigned long timer_status;
  
  	timer_status = ctrl_inw(TMU1_TCR);
  	timer_status &= ~0x100;
  	ctrl_outw(timer_status, TMU1_TCR);
  
  	if (!empty) {
  		sh_dac_output(*buffer_begin, CONFIG_SOUND_SH_DAC_AUDIO_CHANNEL);
  		buffer_begin++;
  
  		if (buffer_begin == data_buffer + BUFFER_SIZE)
  			buffer_begin = data_buffer;
  		if (buffer_begin == buffer_end) {
  			empty = 1;
  			dac_audio_stop_timer();
  		}
  	}
  	return IRQ_HANDLED;
  }
  
  static int __init dac_audio_init(void)
  {
  	int retval;
  
  	if ((device_major = register_sound_dsp(&dac_audio_fops, -1)) < 0) {
  		printk(KERN_ERR "Cannot register dsp device");
  		return device_major;
  	}
  
  	in_use = 0;

  	data_buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL);

  	if (data_buffer == NULL)
  		return -ENOMEM;
  
  	dac_audio_reset();
  	rate = 8000;
  	dac_audio_set_rate();
  
  	retval =

  	    request_irq(TIMER1_IRQ, timer1_interrupt, IRQF_DISABLED, MODNAME, 0);

  	if (retval < 0) {
  		printk(KERN_ERR "sh_dac_audio: IRQ %d request failed
  ",
  		       TIMER1_IRQ);
  		return retval;
  	}
  
  	return 0;
  }
  
  static void __exit dac_audio_exit(void)
  {
  	free_irq(TIMER1_IRQ, 0);
  
  	unregister_sound_dsp(device_major);
  	kfree((void *)data_buffer);
  }
  
  module_init(dac_audio_init);
  module_exit(dac_audio_exit);
  
  MODULE_AUTHOR("Andriy Skulysh, askulysh@image.kiev.ua");
  MODULE_DESCRIPTION("SH DAC sound driver");
  MODULE_LICENSE("GPL");