/*
   *      Low-level parallel-support for PC-style hardware integrated in the 
   *	LASI-Controller (on GSC-Bus) for HP-PARISC Workstations
   *
   *	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.
   *
   *	(C) 1999-2001 by Helge Deller <deller@gmx.de>
   *
   * 
   * based on parport_pc.c by 
   * 	    Grant Guenther <grant@torque.net>
   * 	    Phil Blundell <philb@gnu.org>
   *          Tim Waugh <tim@cyberelk.demon.co.uk>
   *	    Jose Renau <renau@acm.org>

   *          David Campbell

   *          Andrea Arcangeli
   */
  
  #undef DEBUG	/* undef for production */
  
  #include <linux/module.h>
  #include <linux/init.h>

  #include <linux/delay.h>
  #include <linux/errno.h>
  #include <linux/interrupt.h>
  #include <linux/ioport.h>
  #include <linux/kernel.h>
  #include <linux/slab.h>
  #include <linux/pci.h>
  #include <linux/sysctl.h>
  
  #include <asm/io.h>
  #include <asm/dma.h>
  #include <asm/uaccess.h>
  #include <asm/superio.h>
  
  #include <linux/parport.h>
  #include <asm/pdc.h>
  #include <asm/parisc-device.h>
  #include <asm/hardware.h>
  #include "parport_gsc.h"
  
  
  MODULE_AUTHOR("Helge Deller <deller@gmx.de>");
  MODULE_DESCRIPTION("HP-PARISC PC-style parallel port driver");
  MODULE_SUPPORTED_DEVICE("integrated PC-style parallel port");
  MODULE_LICENSE("GPL");
  
  
  /*
   * Clear TIMEOUT BIT in EPP MODE
   *
   * This is also used in SPP detection.
   */
  static int clear_epp_timeout(struct parport *pb)
  {
  	unsigned char r;
  
  	if (!(parport_gsc_read_status(pb) & 0x01))
  		return 1;
  
  	/* To clear timeout some chips require double read */
  	parport_gsc_read_status(pb);
  	r = parport_gsc_read_status(pb);
  	parport_writeb (r | 0x01, STATUS (pb)); /* Some reset by writing 1 */
  	parport_writeb (r & 0xfe, STATUS (pb)); /* Others by writing 0 */
  	r = parport_gsc_read_status(pb);
  
  	return !(r & 0x01);
  }
  
  /*
   * Access functions.
   *
   * Most of these aren't static because they may be used by the
   * parport_xxx_yyy macros.  extern __inline__ versions of several
   * of these are in parport_gsc.h.
   */

  void parport_gsc_init_state(struct pardevice *dev, struct parport_state *s)
  {
  	s->u.pc.ctr = 0xc | (dev->irq_func ? 0x10 : 0x0);
  }
  
  void parport_gsc_save_state(struct parport *p, struct parport_state *s)
  {
  	s->u.pc.ctr = parport_readb (CONTROL (p));
  }
  
  void parport_gsc_restore_state(struct parport *p, struct parport_state *s)
  {
  	parport_writeb (s->u.pc.ctr, CONTROL (p));
  }
  
  struct parport_operations parport_gsc_ops = 
  {
  	.write_data	= parport_gsc_write_data,
  	.read_data	= parport_gsc_read_data,
  
  	.write_control	= parport_gsc_write_control,
  	.read_control	= parport_gsc_read_control,
  	.frob_control	= parport_gsc_frob_control,
  
  	.read_status	= parport_gsc_read_status,
  
  	.enable_irq	= parport_gsc_enable_irq,
  	.disable_irq	= parport_gsc_disable_irq,
  
  	.data_forward	= parport_gsc_data_forward,
  	.data_reverse	= parport_gsc_data_reverse,
  
  	.init_state	= parport_gsc_init_state,
  	.save_state	= parport_gsc_save_state,
  	.restore_state	= parport_gsc_restore_state,
  
  	.epp_write_data	= parport_ieee1284_epp_write_data,
  	.epp_read_data	= parport_ieee1284_epp_read_data,
  	.epp_write_addr	= parport_ieee1284_epp_write_addr,
  	.epp_read_addr	= parport_ieee1284_epp_read_addr,
  
  	.ecp_write_data	= parport_ieee1284_ecp_write_data,
  	.ecp_read_data	= parport_ieee1284_ecp_read_data,
  	.ecp_write_addr	= parport_ieee1284_ecp_write_addr,
  
  	.compat_write_data 	= parport_ieee1284_write_compat,
  	.nibble_read_data	= parport_ieee1284_read_nibble,
  	.byte_read_data		= parport_ieee1284_read_byte,
  
  	.owner		= THIS_MODULE,
  };
  
  /* --- Mode detection ------------------------------------- */
  
  /*
   * Checks for port existence, all ports support SPP MODE
   */

  static int parport_SPP_supported(struct parport *pb)

  {
  	unsigned char r, w;
  
  	/*
  	 * first clear an eventually pending EPP timeout 
  	 * I (sailer@ife.ee.ethz.ch) have an SMSC chipset
  	 * that does not even respond to SPP cycles if an EPP
  	 * timeout is pending
  	 */
  	clear_epp_timeout(pb);
  
  	/* Do a simple read-write test to make sure the port exists. */
  	w = 0xc;
  	parport_writeb (w, CONTROL (pb));
  
  	/* Is there a control register that we can read from?  Some
  	 * ports don't allow reads, so read_control just returns a
  	 * software copy. Some ports _do_ allow reads, so bypass the
  	 * software copy here.  In addition, some bits aren't
  	 * writable. */
  	r = parport_readb (CONTROL (pb));
  	if ((r & 0xf) == w) {
  		w = 0xe;
  		parport_writeb (w, CONTROL (pb));
  		r = parport_readb (CONTROL (pb));
  		parport_writeb (0xc, CONTROL (pb));
  		if ((r & 0xf) == w)
  			return PARPORT_MODE_PCSPP;
  	}
  
  	/* Try the data register.  The data lines aren't tri-stated at
  	 * this stage, so we expect back what we wrote. */
  	w = 0xaa;
  	parport_gsc_write_data (pb, w);
  	r = parport_gsc_read_data (pb);
  	if (r == w) {
  		w = 0x55;
  		parport_gsc_write_data (pb, w);
  		r = parport_gsc_read_data (pb);
  		if (r == w)
  			return PARPORT_MODE_PCSPP;
  	}
  
  	return 0;
  }
  
  /* Detect PS/2 support.
   *
   * Bit 5 (0x20) sets the PS/2 data direction; setting this high
   * allows us to read data from the data lines.  In theory we would get back
   * 0xff but any peripheral attached to the port may drag some or all of the
   * lines down to zero.  So if we get back anything that isn't the contents
   * of the data register we deem PS/2 support to be present. 
   *
   * Some SPP ports have "half PS/2" ability - you can't turn off the line
   * drivers, but an external peripheral with sufficiently beefy drivers of
   * its own can overpower them and assert its own levels onto the bus, from
   * where they can then be read back as normal.  Ports with this property
   * and the right type of device attached are likely to fail the SPP test,
   * (as they will appear to have stuck bits) and so the fact that they might
   * be misdetected here is rather academic. 
   */

  static int parport_PS2_supported(struct parport *pb)

  {
  	int ok = 0;
    
  	clear_epp_timeout(pb);
  
  	/* try to tri-state the buffer */
  	parport_gsc_data_reverse (pb);
  	
  	parport_gsc_write_data(pb, 0x55);
  	if (parport_gsc_read_data(pb) != 0x55) ok++;
  
  	parport_gsc_write_data(pb, 0xaa);
  	if (parport_gsc_read_data(pb) != 0xaa) ok++;
  
  	/* cancel input mode */
  	parport_gsc_data_forward (pb);
  
  	if (ok) {
  		pb->modes |= PARPORT_MODE_TRISTATE;
  	} else {
  		struct parport_gsc_private *priv = pb->private_data;
  		priv->ctr_writable &= ~0x20;
  	}
  
  	return ok;
  }
  
  
  /* --- Initialisation code -------------------------------- */

  struct parport *parport_gsc_probe_port(unsigned long base,
  				       unsigned long base_hi, int irq,

  				       int dma, struct parisc_device *padev)

  {
  	struct parport_gsc_private *priv;
  	struct parport_operations *ops;
  	struct parport tmp;
  	struct parport *p = &tmp;

  	priv = kzalloc (sizeof (struct parport_gsc_private), GFP_KERNEL);

  	if (!priv) {
  		printk (KERN_DEBUG "parport (0x%lx): no memory!
  ", base);
  		return NULL;
  	}

  	ops = kmemdup(&parport_gsc_ops, sizeof(struct parport_operations),
  		      GFP_KERNEL);

  	if (!ops) {
  		printk (KERN_DEBUG "parport (0x%lx): no memory for ops!
  ",
  			base);
  		kfree (priv);
  		return NULL;
  	}

  	priv->ctr = 0xc;
  	priv->ctr_writable = 0xff;
  	priv->dma_buf = 0;
  	priv->dma_handle = 0;

  	p->base = base;
  	p->base_hi = base_hi;
  	p->irq = irq;
  	p->dma = dma;
  	p->modes = PARPORT_MODE_PCSPP | PARPORT_MODE_SAFEININT;
  	p->ops = ops;
  	p->private_data = priv;
  	p->physport = p;
  	if (!parport_SPP_supported (p)) {
  		/* No port. */
  		kfree (priv);

  		kfree(ops);

  		return NULL;
  	}
  	parport_PS2_supported (p);
  
  	if (!(p = parport_register_port(base, PARPORT_IRQ_NONE,
  					PARPORT_DMA_NONE, ops))) {
  		kfree (priv);
  		kfree (ops);
  		return NULL;
  	}

  	p->dev = &padev->dev;

  	p->base_hi = base_hi;
  	p->modes = tmp.modes;
  	p->size = (p->modes & PARPORT_MODE_EPP)?8:3;
  	p->private_data = priv;
  
  	printk(KERN_INFO "%s: PC-style at 0x%lx", p->name, p->base);
  	p->irq = irq;
  	if (p->irq == PARPORT_IRQ_AUTO) {
  		p->irq = PARPORT_IRQ_NONE;
  	}
  	if (p->irq != PARPORT_IRQ_NONE) {
  		printk(", irq %d", p->irq);
  
  		if (p->dma == PARPORT_DMA_AUTO) {
  			p->dma = PARPORT_DMA_NONE;
  		}
  	}
  	if (p->dma == PARPORT_DMA_AUTO) /* To use DMA, giving the irq
                                             is mandatory (see above) */
  		p->dma = PARPORT_DMA_NONE;
  
  	printk(" [");
  #define printmode(x) {if(p->modes&PARPORT_MODE_##x){printk("%s%s",f?",":"",#x);f++;}}
  	{
  		int f = 0;
  		printmode(PCSPP);
  		printmode(TRISTATE);
  		printmode(COMPAT)
  		printmode(EPP);
  //		printmode(ECP);
  //		printmode(DMA);
  	}
  #undef printmode
  	printk("]
  ");
  
  	if (p->irq != PARPORT_IRQ_NONE) {

  		if (request_irq (p->irq, parport_irq_handler,

  				 0, p->name, p)) {
  			printk (KERN_WARNING "%s: irq %d in use, "
  				"resorting to polled operation
  ",
  				p->name, p->irq);
  			p->irq = PARPORT_IRQ_NONE;
  			p->dma = PARPORT_DMA_NONE;
  		}
  	}
  
  	/* Done probing.  Now put the port into a sensible start-up state. */
  
  	parport_gsc_write_data(p, 0);
  	parport_gsc_data_forward (p);
  
  	/* Now that we've told the sharing engine about the port, and
  	   found out its characteristics, let the high-level drivers
  	   know about it. */
  	parport_announce_port (p);
  
  	return p;
  }
  
  
  #define PARPORT_GSC_OFFSET 0x800

  static int parport_count;

  static int parport_init_chip(struct parisc_device *dev)

  {
  	struct parport *p;
  	unsigned long port;
  
  	if (!dev->irq) {

  		printk(KERN_WARNING "IRQ not found for parallel device at 0x%llx
  ",
  			(unsigned long long)dev->hpa.start);

  		return -ENODEV;
  	}

  	port = dev->hpa.start + PARPORT_GSC_OFFSET;

  	
  	/* some older machines with ASP-chip don't support
  	 * the enhanced parport modes.
  	 */
  	if (boot_cpu_data.cpu_type > pcxt && !pdc_add_valid(port+4)) {
  
  		/* Initialize bidirectional-mode (0x10) & data-tranfer-mode #1 (0x20) */

  		printk("%s: initialize bidirectional-mode.
  ", __func__);

  		parport_writeb ( (0x10 + 0x20), port + 4);
  
  	} else {

  		printk("%s: enhanced parport-modes not supported.
  ", __func__);

  	}
  	
  	p = parport_gsc_probe_port(port, 0, dev->irq,

  			/* PARPORT_IRQ_NONE */ PARPORT_DMA_NONE, dev);

  	if (p)
  		parport_count++;

  	dev_set_drvdata(&dev->dev, p);

  
  	return 0;
  }

  static int parport_remove_chip(struct parisc_device *dev)

  {

  	struct parport *p = dev_get_drvdata(&dev->dev);

  	if (p) {
  		struct parport_gsc_private *priv = p->private_data;
  		struct parport_operations *ops = p->ops;
  		parport_remove_port(p);
  		if (p->dma != PARPORT_DMA_NONE)
  			free_dma(p->dma);
  		if (p->irq != PARPORT_IRQ_NONE)
  			free_irq(p->irq, p);
  		if (priv->dma_buf)
  			pci_free_consistent(priv->dev, PAGE_SIZE,
  					    priv->dma_buf,
  					    priv->dma_handle);
  		kfree (p->private_data);
  		parport_put_port(p);
  		kfree (ops); /* hope no-one cached it */
  	}
  	return 0;
  }
  
  static struct parisc_device_id parport_tbl[] = {
  	{ HPHW_FIO, HVERSION_REV_ANY_ID, HVERSION_ANY_ID, 0x74 },
  	{ 0, }
  };
  
  MODULE_DEVICE_TABLE(parisc, parport_tbl);
  
  static struct parisc_driver parport_driver = {
  	.name		= "Parallel",
  	.id_table	= parport_tbl,
  	.probe		= parport_init_chip,

  	.remove		= parport_remove_chip,

  };

  int parport_gsc_init(void)

  {
  	return register_parisc_driver(&parport_driver);
  }

  static void parport_gsc_exit(void)

  {
  	unregister_parisc_driver(&parport_driver);
  }
  
  module_init(parport_gsc_init);
  module_exit(parport_gsc_exit);