/*
   * sound/oss/uart401.c
   *
   * MPU-401 UART driver (formerly uart401_midi.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.
   *
   * Changes:
   *	Alan Cox		Reformatted, removed sound_mem usage, use normal Linux
   *				interrupt allocation. Protect against bogus unload
   *				Fixed to allow IRQ > 15
   *	Christoph Hellwig	Adapted to module_init/module_exit
   *	Arnaldo C. de Melo	got rid of check_region
   *
   * Status:
   *		Untested
   */
  
  #include <linux/init.h>
  #include <linux/interrupt.h>
  #include <linux/module.h>
  #include <linux/slab.h>
  #include <linux/spinlock.h>
  #include "sound_config.h"
  
  #include "mpu401.h"
  
  struct uart401_devc
  {
  	int             base;
  	int             irq;
  	int            *osp;
  	void            (*midi_input_intr) (int dev, unsigned char data);
  	int             opened, disabled;
  	volatile unsigned char input_byte;
  	int             my_dev;
  	int             share_irq;
  	spinlock_t	lock;
  };
  
  #define	DATAPORT   (devc->base)
  #define	COMDPORT   (devc->base+1)
  #define	STATPORT   (devc->base+1)
  
  static int uart401_status(struct uart401_devc *devc)
  {
  	return inb(STATPORT);
  }
  
  #define input_avail(devc) (!(uart401_status(devc)&INPUT_AVAIL))
  #define output_ready(devc)	(!(uart401_status(devc)&OUTPUT_READY))
  
  static void uart401_cmd(struct uart401_devc *devc, unsigned char cmd)
  {
  	outb((cmd), COMDPORT);
  }
  
  static int uart401_read(struct uart401_devc *devc)
  {
  	return inb(DATAPORT);
  }
  
  static void uart401_write(struct uart401_devc *devc, unsigned char byte)
  {
  	outb((byte), DATAPORT);
  }
  
  #define	OUTPUT_READY	0x40
  #define	INPUT_AVAIL	0x80
  #define	MPU_ACK		0xFE
  #define	MPU_RESET	0xFF
  #define	UART_MODE_ON	0x3F
  
  static int      reset_uart401(struct uart401_devc *devc);
  static void     enter_uart_mode(struct uart401_devc *devc);
  
  static void uart401_input_loop(struct uart401_devc *devc)
  {
  	int work_limit=30000;
  	
  	while (input_avail(devc) && --work_limit)
  	{
  		unsigned char   c = uart401_read(devc);
  
  		if (c == MPU_ACK)
  			devc->input_byte = c;
  		else if (devc->opened & OPEN_READ && devc->midi_input_intr)
  			devc->midi_input_intr(devc->my_dev, c);
  	}
  	if(work_limit==0)
  		printk(KERN_WARNING "Too much work in interrupt on uart401 (0x%X). UART jabbering ??
  ", devc->base);
  }
  
  irqreturn_t uart401intr(int irq, void *dev_id)
  {
  	struct uart401_devc *devc = dev_id;
  
  	if (devc == NULL)
  	{
  		printk(KERN_ERR "uart401: bad devc
  ");
  		return IRQ_NONE;
  	}
  
  	if (input_avail(devc))
  		uart401_input_loop(devc);
  	return IRQ_HANDLED;
  }
  
  static int
  uart401_open(int dev, int mode,
  	     void            (*input) (int dev, unsigned char data),
  	     void            (*output) (int dev)
  )
  {
  	struct uart401_devc *devc = (struct uart401_devc *)
  				    midi_devs[dev]->devc;
  
  	if (devc->opened)
  		return -EBUSY;
  
  	/* Flush the UART */
  	
  	while (input_avail(devc))
  		uart401_read(devc);
  
  	devc->midi_input_intr = input;
  	devc->opened = mode;
  	enter_uart_mode(devc);
  	devc->disabled = 0;
  
  	return 0;
  }
  
  static void uart401_close(int dev)
  {
  	struct uart401_devc *devc = (struct uart401_devc *)
  				    midi_devs[dev]->devc;
  
  	reset_uart401(devc);
  	devc->opened = 0;
  }
  
  static int uart401_out(int dev, unsigned char midi_byte)
  {
  	int timeout;
  	unsigned long flags;
  	struct uart401_devc *devc = (struct uart401_devc *)
  				    midi_devs[dev]->devc;
  
  	if (devc->disabled)
  		return 1;
  	/*
  	 * Test for input since pending input seems to block the output.
  	 */
  
  	spin_lock_irqsave(&devc->lock,flags);	
  	if (input_avail(devc))
  		uart401_input_loop(devc);
  
  	spin_unlock_irqrestore(&devc->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(devc); timeout--);
  
  	if (!output_ready(devc))
  	{
  		  printk(KERN_WARNING "uart401: Timeout - Device not responding
  ");
  		  devc->disabled = 1;
  		  reset_uart401(devc);
  		  enter_uart_mode(devc);
  		  return 1;
  	}
  	uart401_write(devc, midi_byte);
  	return 1;
  }
  
  static inline int uart401_start_read(int dev)
  {
  	return 0;
  }
  
  static inline int uart401_end_read(int dev)
  {
  	return 0;
  }
  
  static inline void uart401_kick(int dev)
  {
  }
  
  static inline int uart401_buffer_status(int dev)
  {
  	return 0;
  }
  
  #define MIDI_SYNTH_NAME	"MPU-401 UART"
  #define MIDI_SYNTH_CAPS	SYNTH_CAP_INPUT
  #include "midi_synth.h"
  
  static const struct midi_operations uart401_operations =
  {
  	.owner		= THIS_MODULE,
  	.info		= {"MPU-401 (UART) MIDI", 0, 0, SNDCARD_MPU401},
  	.converter	= &std_midi_synth,
  	.in_info	= {0},
  	.open		= uart401_open,
  	.close		= uart401_close,
  	.outputc	= uart401_out,
  	.start_read	= uart401_start_read,
  	.end_read	= uart401_end_read,
  	.kick		= uart401_kick,
  	.buffer_status	= uart401_buffer_status,
  };
  
  static void enter_uart_mode(struct uart401_devc *devc)
  {
  	int ok, timeout;
  	unsigned long flags;
  
  	spin_lock_irqsave(&devc->lock,flags);	
  	for (timeout = 30000; timeout > 0 && !output_ready(devc); timeout--);
  
  	devc->input_byte = 0;
  	uart401_cmd(devc, UART_MODE_ON);
  
  	ok = 0;
  	for (timeout = 50000; timeout > 0 && !ok; timeout--)
  		if (devc->input_byte == MPU_ACK)
  			ok = 1;
  		else if (input_avail(devc))
  			if (uart401_read(devc) == MPU_ACK)
  				ok = 1;
  
  	spin_unlock_irqrestore(&devc->lock,flags);
  }
  
  static int reset_uart401(struct uart401_devc *devc)
  {
  	int ok, timeout, n;
  
  	/*
  	 * Send the RESET command. Try again if no success at the first time.
  	 */
  
  	ok = 0;
  
  	for (n = 0; n < 2 && !ok; n++)
  	{
  		for (timeout = 30000; timeout > 0 && !output_ready(devc); timeout--);
  		devc->input_byte = 0;
  		uart401_cmd(devc, MPU_RESET);
  
  		/*
  		 * Wait at least 25 msec. This method is not accurate so let's make the
  		 * loop bit longer. Cannot sleep since this is called during boot.
  		 */
  
  		for (timeout = 50000; timeout > 0 && !ok; timeout--)
  		{
  			if (devc->input_byte == MPU_ACK)	/* Interrupt */
  				ok = 1;
  			else if (input_avail(devc))
  			{
  				if (uart401_read(devc) == MPU_ACK)
  					ok = 1;
  			}
  		}
  	}
  
  	/* Flush input before enabling interrupts */
  	if (ok)
  		uart401_input_loop(devc);
  	else
  		DDB(printk("Reset UART401 failed - No hardware detected.
  "));
  
  	return ok;
  }
  
  int probe_uart401(struct address_info *hw_config, struct module *owner)
  {
  	struct uart401_devc *devc;
  	char *name = "MPU-401 (UART) MIDI";
  	int ok = 0;
  	unsigned long flags;
  
  	DDB(printk("Entered probe_uart401()
  "));
  
  	/* Default to "not found" */
  	hw_config->slots[4] = -1;
  
  	if (!request_region(hw_config->io_base, 4, "MPU-401 UART")) {
  		printk(KERN_INFO "uart401: could not request_region(%d, 4)
  ", hw_config->io_base);
  		return 0;
  	}
  
  	devc = kmalloc(sizeof(struct uart401_devc), GFP_KERNEL);
  	if (!devc) {
  		printk(KERN_WARNING "uart401: Can't allocate memory
  ");
  		goto cleanup_region;
  	}
  
  	devc->base = hw_config->io_base;
  	devc->irq = hw_config->irq;
  	devc->osp = hw_config->osp;
  	devc->midi_input_intr = NULL;
  	devc->opened = 0;
  	devc->input_byte = 0;
  	devc->my_dev = 0;
  	devc->share_irq = 0;
  	spin_lock_init(&devc->lock);
  
  	spin_lock_irqsave(&devc->lock,flags);	
  	ok = reset_uart401(devc);
  	spin_unlock_irqrestore(&devc->lock,flags);
  
  	if (!ok)
  		goto cleanup_devc;
  
  	if (hw_config->name)
  		name = hw_config->name;
  
  	if (devc->irq < 0) {
  		devc->share_irq = 1;
  		devc->irq *= -1;
  	} else
  		devc->share_irq = 0;
  
  	if (!devc->share_irq)
  		if (request_irq(devc->irq, uart401intr, 0, "MPU-401 UART", devc) < 0) {
  			printk(KERN_WARNING "uart401: Failed to allocate IRQ%d
  ", devc->irq);
  			devc->share_irq = 1;
  		}
  	devc->my_dev = sound_alloc_mididev();
  	enter_uart_mode(devc);
  
  	if (devc->my_dev == -1) {
  		printk(KERN_INFO "uart401: Too many midi devices detected
  ");
  		goto cleanup_irq;
  	}
  	conf_printf(name, hw_config);
  	midi_devs[devc->my_dev] = kmemdup(&uart401_operations,
  					  sizeof(struct midi_operations),
  					  GFP_KERNEL);
  	if (!midi_devs[devc->my_dev]) {
  		printk(KERN_ERR "uart401: Failed to allocate memory
  ");
  		goto cleanup_unload_mididev;
  	}
  
  	if (owner)
  		midi_devs[devc->my_dev]->owner = owner;
  	
  	midi_devs[devc->my_dev]->devc = devc;
  	midi_devs[devc->my_dev]->converter = kmemdup(&std_midi_synth,
  						     sizeof(struct synth_operations),
  						     GFP_KERNEL);
  
  	if (!midi_devs[devc->my_dev]->converter) {
  		printk(KERN_WARNING "uart401: Failed to allocate memory
  ");
  		goto cleanup_midi_devs;
  	}
  	strcpy(midi_devs[devc->my_dev]->info.name, name);
  	midi_devs[devc->my_dev]->converter->id = "UART401";
  	midi_devs[devc->my_dev]->converter->midi_dev = devc->my_dev;
  
  	if (owner)
  		midi_devs[devc->my_dev]->converter->owner = owner;
  
  	hw_config->slots[4] = devc->my_dev;
  	sequencer_init();
  	devc->opened = 0;
  	return 1;
  cleanup_midi_devs:
  	kfree(midi_devs[devc->my_dev]);
  cleanup_unload_mididev:
  	sound_unload_mididev(devc->my_dev);
  cleanup_irq:
  	if (!devc->share_irq)
  		free_irq(devc->irq, devc);
  cleanup_devc:
  	kfree(devc);
  cleanup_region:
  	release_region(hw_config->io_base, 4);
  	return 0;
  }
  
  void unload_uart401(struct address_info *hw_config)
  {
  	struct uart401_devc *devc;
  	int n=hw_config->slots[4];
  	
  	/* Not set up */
  	if(n==-1 || midi_devs[n]==NULL)
  		return;
  		
  	/* Not allocated (erm ??) */
  	
  	devc = midi_devs[hw_config->slots[4]]->devc;
  	if (devc == NULL)
  		return;
  
  	reset_uart401(devc);
  	release_region(hw_config->io_base, 4);
  
  	if (!devc->share_irq)
  		free_irq(devc->irq, devc);
  	kfree(midi_devs[devc->my_dev]->converter);
  	kfree(midi_devs[devc->my_dev]);
  	kfree(devc);
  
  	/* This kills midi_devs[x] */
  	sound_unload_mididev(hw_config->slots[4]);
  }
  
  EXPORT_SYMBOL(probe_uart401);
  EXPORT_SYMBOL(unload_uart401);
  EXPORT_SYMBOL(uart401intr);
  
  static struct address_info cfg_mpu;
  
  static int io = -1;
  static int irq = -1;
  
  module_param(io, int, 0444);
  module_param(irq, int, 0444);
  
  
  static int __init init_uart401(void)
  {
  	cfg_mpu.irq = irq;
  	cfg_mpu.io_base = io;
  
  	/* Can be loaded either for module use or to provide functions
  	   to others */
  	if (cfg_mpu.io_base != -1 && cfg_mpu.irq != -1) {
  		printk(KERN_INFO "MPU-401 UART driver Copyright (C) Hannu Savolainen 1993-1997");
  		if (!probe_uart401(&cfg_mpu, THIS_MODULE))
  			return -ENODEV;
  	}
  
  	return 0;
  }
  
  static void __exit cleanup_uart401(void)
  {
  	if (cfg_mpu.io_base != -1 && cfg_mpu.irq != -1)
  		unload_uart401(&cfg_mpu);
  }
  
  module_init(init_uart401);
  module_exit(cleanup_uart401);
  
  #ifndef MODULE
  static int __init setup_uart401(char *str)
  {
  	/* io, irq */
  	int ints[3];
  	
  	str = get_options(str, ARRAY_SIZE(ints), ints);
  
  	io = ints[1];
  	irq = ints[2];
  	
  	return 1;
  }
  
  __setup("uart401=", setup_uart401);
  #endif
  MODULE_LICENSE("GPL");