/*
   * sound/oss/uart6850.c
   *
   *
   * Copyright (C) by Hannu Savolainen 1993-1997
   *
   * OSS/Free for Linux is distributed under the GNU GENERAL PUBLIC LICENSE (GPL)
   * Version 2 (June 1991). See the "COPYING" file distributed with this software
   * for more info.
   * Extended by Alan Cox for Red Hat Software. Now a loadable MIDI driver.
   * 28/4/97 - (C) Copyright Alan Cox. Released under the GPL version 2.
   *
   * Alan Cox:		Updated for new modular code. Removed snd_* irq handling. Now
   *			uses native linux resources
   * Christoph Hellwig:	Adapted to module_init/module_exit
   * Jeff Garzik:		Made it work again, in theory
   *			FIXME: If the request_irq() succeeds, the probe succeeds. Ug.
   *
   *	Status: Testing required (no shit -jgarzik)
   *
   *
   */
  
  #include <linux/init.h>
  #include <linux/interrupt.h>
  #include <linux/module.h>
  #include <linux/spinlock.h>
  /* Mon Nov 22 22:38:35 MET 1993 marco@driq.home.usn.nl:
   *      added 6850 support, used with COVOX SoundMaster II and custom cards.
   */
  
  #include "sound_config.h"
  
  static int uart6850_base = 0x330;
  
  static int *uart6850_osp;
  
  #define	DATAPORT   (uart6850_base)
  #define	COMDPORT   (uart6850_base+1)
  #define	STATPORT   (uart6850_base+1)
  
  static int uart6850_status(void)
  {
  	return inb(STATPORT);
  }
  
  #define input_avail()		(uart6850_status()&INPUT_AVAIL)
  #define output_ready()		(uart6850_status()&OUTPUT_READY)
  
  static void uart6850_cmd(unsigned char cmd)
  {
  	outb(cmd, COMDPORT);
  }
  
  static int uart6850_read(void)
  {
  	return inb(DATAPORT);
  }
  
  static void uart6850_write(unsigned char byte)
  {
  	outb(byte, DATAPORT);
  }
  
  #define	OUTPUT_READY	0x02	/* Mask for data ready Bit */
  #define	INPUT_AVAIL	0x01	/* Mask for Data Send Ready Bit */
  
  #define	UART_RESET	0x95
  #define	UART_MODE_ON	0x03
  
  static int uart6850_opened;
  static int uart6850_irq;
  static int uart6850_detected;
  static int my_dev;
  static DEFINE_SPINLOCK(lock);
  
  static void (*midi_input_intr) (int dev, unsigned char data);
  static void poll_uart6850(unsigned long dummy);
  
  
  static DEFINE_TIMER(uart6850_timer, poll_uart6850, 0, 0);
  
  static void uart6850_input_loop(void)
  {
  	int count = 10;
  
  	while (count)
  	{
  		/*
  		 * Not timed out
  		 */
  		if (input_avail())
  		{
  			unsigned char c = uart6850_read();
  			count = 100;
  			if (uart6850_opened & OPEN_READ)
  				midi_input_intr(my_dev, c);
  		}
  		else
  		{
  			while (!input_avail() && count)
  				count--;
  		}
  	}
  }
  
  static irqreturn_t m6850intr(int irq, void *dev_id)
  {
  	if (input_avail())
  		uart6850_input_loop();
  	return IRQ_HANDLED;
  }
  
  /*
   *	It looks like there is no input interrupts in the UART mode. Let's try
   *	polling.
   */
  
  static void poll_uart6850(unsigned long dummy)
  {
  	unsigned long flags;
  
  	if (!(uart6850_opened & OPEN_READ))
  		return;		/* Device has been closed */
  
  	spin_lock_irqsave(&lock,flags);
  	if (input_avail())
  		uart6850_input_loop();
  
  	uart6850_timer.expires = 1 + jiffies;
  	add_timer(&uart6850_timer);
  	
  	/*
  	 *	Come back later
  	 */
  
  	spin_unlock_irqrestore(&lock,flags);
  }
  
  static int uart6850_open(int dev, int mode,
  	      void            (*input) (int dev, unsigned char data),
  	      void            (*output) (int dev)
  )
  {
  	if (uart6850_opened)
  	{
  /*		  printk("Midi6850: Midi busy
  ");*/
  		  return -EBUSY;
  	}
  
  	uart6850_cmd(UART_RESET);
  	uart6850_input_loop();
  	midi_input_intr = input;
  	uart6850_opened = mode;
  	poll_uart6850(0);	/*
  				 * Enable input polling
  				 */
  
  	return 0;
  }
  
  static void uart6850_close(int dev)
  {
  	uart6850_cmd(UART_MODE_ON);
  	del_timer(&uart6850_timer);
  	uart6850_opened = 0;
  }
  
  static int uart6850_out(int dev, unsigned char midi_byte)
  {
  	int timeout;
  	unsigned long flags;
  
  	/*
  	 * Test for input since pending input seems to block the output.
  	 */
  
  	spin_lock_irqsave(&lock,flags);
  
  	if (input_avail())
  		uart6850_input_loop();
  
  	spin_unlock_irqrestore(&lock,flags);
  
  	/*
  	 * Sometimes it takes about 13000 loops before the output becomes ready
  	 * (After reset). Normally it takes just about 10 loops.
  	 */
  
  	for (timeout = 30000; timeout > 0 && !output_ready(); timeout--);	/*
  										 * Wait
  										 */
  	if (!output_ready())
  	{
  		printk(KERN_WARNING "Midi6850: Timeout
  ");
  		return 0;
  	}
  	uart6850_write(midi_byte);
  	return 1;
  }
  
  static inline int uart6850_command(int dev, unsigned char *midi_byte)
  {
  	return 1;
  }
  
  static inline int uart6850_start_read(int dev)
  {
  	return 0;
  }
  
  static inline int uart6850_end_read(int dev)
  {
  	return 0;
  }
  
  static inline void uart6850_kick(int dev)
  {
  }
  
  static inline int uart6850_buffer_status(int dev)
  {
  	return 0;		/*
  				 * No data in buffers
  				 */
  }
  
  #define MIDI_SYNTH_NAME	"6850 UART Midi"
  #define MIDI_SYNTH_CAPS	SYNTH_CAP_INPUT
  #include "midi_synth.h"
  
  static struct midi_operations uart6850_operations =
  {
  	.owner		= THIS_MODULE,
  	.info		= {"6850 UART", 0, 0, SNDCARD_UART6850},
  	.converter	= &std_midi_synth,
  	.in_info	= {0},
  	.open		= uart6850_open,
  	.close		= uart6850_close,
  	.outputc	= uart6850_out,
  	.start_read	= uart6850_start_read,
  	.end_read	= uart6850_end_read,
  	.kick		= uart6850_kick,
  	.command	= uart6850_command,
  	.buffer_status	= uart6850_buffer_status
  };
  
  
  static void __init attach_uart6850(struct address_info *hw_config)
  {
  	int ok, timeout;
  	unsigned long   flags;
  
  	if (!uart6850_detected)
  		return;
  
  	if ((my_dev = sound_alloc_mididev()) == -1)
  	{
  		printk(KERN_INFO "uart6850: Too many midi devices detected
  ");
  		return;
  	}
  	uart6850_base = hw_config->io_base;
  	uart6850_osp = hw_config->osp;
  	uart6850_irq = hw_config->irq;
  
  	spin_lock_irqsave(&lock,flags);
  
  	for (timeout = 30000; timeout > 0 && !output_ready(); timeout--);	/*
  										 * Wait
  										 */
  	uart6850_cmd(UART_MODE_ON);
  	ok = 1;
  	spin_unlock_irqrestore(&lock,flags);
  
  	conf_printf("6850 Midi Interface", hw_config);
  
  	std_midi_synth.midi_dev = my_dev;
  	hw_config->slots[4] = my_dev;
  	midi_devs[my_dev] = &uart6850_operations;
  	sequencer_init();
  }
  
  static inline int reset_uart6850(void)
  {
  	uart6850_read();
  	return 1;		/*
  				 * OK
  				 */
  }
  
  static int __init probe_uart6850(struct address_info *hw_config)
  {
  	int ok;
  
  	uart6850_osp = hw_config->osp;
  	uart6850_base = hw_config->io_base;
  	uart6850_irq = hw_config->irq;
  
  	if (request_irq(uart6850_irq, m6850intr, 0, "MIDI6850", NULL) < 0)
  		return 0;
  
  	ok = reset_uart6850();
  	uart6850_detected = ok;
  	return ok;
  }
  
  static void __exit unload_uart6850(struct address_info *hw_config)
  {
  	free_irq(hw_config->irq, NULL);
  	sound_unload_mididev(hw_config->slots[4]);
  }
  
  static struct address_info cfg_mpu;
  
  static int __initdata io = -1;
  static int __initdata irq = -1;
  
  module_param(io, int, 0);
  module_param(irq, int, 0);
  
  static int __init init_uart6850(void)
  {
  	cfg_mpu.io_base = io;
  	cfg_mpu.irq = irq;
  
  	if (cfg_mpu.io_base == -1 || cfg_mpu.irq == -1) {
  		printk(KERN_INFO "uart6850: irq and io must be set.
  ");
  		return -EINVAL;
  	}
  
  	if (probe_uart6850(&cfg_mpu))
  		return -ENODEV;
  	attach_uart6850(&cfg_mpu);
  
  	return 0;
  }
  
  static void __exit cleanup_uart6850(void)
  {
  	unload_uart6850(&cfg_mpu);
  }
  
  module_init(init_uart6850);
  module_exit(cleanup_uart6850);
  
  #ifndef MODULE
  static int __init setup_uart6850(char *str)
  {
  	/* io, irq */
  	int ints[3];
  	
  	str = get_options(str, ARRAY_SIZE(ints), ints);
  	
  	io = ints[1];
  	irq = ints[2];
  
  	return 1;
  }
  __setup("uart6850=", setup_uart6850);
  #endif
  MODULE_LICENSE("GPL");