/*
 *      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.
 *
 *	by Helge Deller <deller@gmx.de>
 *
 * 
 * based on parport_pc.c by 
 * 	    Grant Guenther <grant@torque.net>
 * 	    Phil Blundell <Philip.Blundell@pobox.com>
 *          Tim Waugh <tim@cyberelk.demon.co.uk>
 *	    Jose Renau <renau@acm.org>
 *          David Campbell <campbell@torque.net>
 *          Andrea Arcangeli
 */

#undef DEBUG	/* undef for production */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.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 <linux/parport.h>
#include <asm/gsc.h>
#include <asm/pdc.h>
#include <asm/hardware.h>
#include <asm/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");


/*
 * 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.
 */

static void parport_gsc_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
	parport_generic_irq(irq, (struct parport *) dev_id, regs);
}

void parport_gsc_write_data(struct parport *p, unsigned char d)
{
	parport_writeb (d, DATA (p));
}

unsigned char parport_gsc_read_data(struct parport *p)
{
	unsigned char c = parport_readb (DATA (p));
	return c;
}

void parport_gsc_write_control(struct parport *p, unsigned char d)
{
	const unsigned char wm = (PARPORT_CONTROL_STROBE |
				  PARPORT_CONTROL_AUTOFD |
				  PARPORT_CONTROL_INIT |
				  PARPORT_CONTROL_SELECT);

	/* Take this out when drivers have adapted to the newer interface. */
	if (d & 0x20) {
		pr_debug("%s (%s): use data_reverse for this!\n",
			    p->name, p->cad->name);
		parport_gsc_data_reverse (p);
	}

	__parport_gsc_frob_control (p, wm, d & wm);
}

unsigned char parport_gsc_read_control(struct parport *p)
{
	const unsigned char wm = (PARPORT_CONTROL_STROBE |
				  PARPORT_CONTROL_AUTOFD |
				  PARPORT_CONTROL_INIT |
				  PARPORT_CONTROL_SELECT);
	const struct parport_gsc_private *priv = p->physport->private_data;
	return priv->ctr & wm; /* Use soft copy */
}

unsigned char parport_gsc_frob_control (struct parport *p, unsigned char mask,
				       unsigned char val)
{
	const unsigned char wm = (PARPORT_CONTROL_STROBE |
				  PARPORT_CONTROL_AUTOFD |
				  PARPORT_CONTROL_INIT |
				  PARPORT_CONTROL_SELECT);

	/* Take this out when drivers have adapted to the newer interface. */
	if (mask & 0x20) {
		pr_debug("%s (%s): use data_%s for this!\n",
			p->name, p->cad->name,
			(val & 0x20) ? "reverse" : "forward");
		if (val & 0x20)
			parport_gsc_data_reverse (p);
		else
			parport_gsc_data_forward (p);
	}

	/* Restrict mask and val to control lines. */
	mask &= wm;
	val &= wm;

	return __parport_gsc_frob_control (p, mask, val);
}

unsigned char parport_gsc_read_status(struct parport *p)
{
	return parport_readb (STATUS (p));
}

void parport_gsc_disable_irq(struct parport *p)
{
	__parport_gsc_frob_control (p, 0x10, 0);
}

void parport_gsc_enable_irq(struct parport *p)
{
	__parport_gsc_frob_control (p, 0x10, 0x10);
}

void parport_gsc_data_forward (struct parport *p)
{
	__parport_gsc_frob_control (p, 0x20, 0);
}

void parport_gsc_data_reverse (struct parport *p)
{
	__parport_gsc_frob_control (p, 0x20, 0x20);
}

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));
}

void parport_gsc_inc_use_count(void)
{
	MOD_INC_USE_COUNT;
}

void parport_gsc_dec_use_count(void)
{
	MOD_DEC_USE_COUNT;
}


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,

	inc_use_count:	parport_gsc_inc_use_count,
	dec_use_count:	parport_gsc_dec_use_count,

	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,
};

/* --- Mode detection ------------------------------------- */

/*
 * Checks for port existence, all ports support SPP MODE
 */
static int __devinit 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 __devinit 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 *__devinit parport_gsc_probe_port (unsigned long base,
						 unsigned long base_hi,
						 int irq, int dma,
						 struct pci_dev *dev)
{
	struct parport_gsc_private *priv;
	struct parport_operations *ops;
	struct parport tmp;
	struct parport *p = &tmp;

#if 1
#warning Take this out when region handling works again, <deller@gmx,de>
#else
	if (check_region(base, 3)) 
	    return NULL;
#endif
	    
	priv = kmalloc (sizeof (struct parport_gsc_private), GFP_KERNEL);
	if (!priv) {
		printk (KERN_DEBUG "parport (0x%lx): no memory!\n", base);
		return NULL;
	}
	ops = kmalloc (sizeof (struct parport_operations), GFP_KERNEL);
	if (!ops) {
		printk (KERN_DEBUG "parport (0x%lx): no memory for ops!\n",
			base);
		kfree (priv);
		return NULL;
	}
	memcpy (ops, &parport_gsc_ops, sizeof (struct parport_operations));
	priv->ctr = 0xc;
	priv->ctr_writable = 0xff;
	priv->dma_buf = 0;
	priv->dma_handle = 0;
	priv->dev = dev;
	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);
		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->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("]\n");
	parport_proc_register(p);

	request_region (p->base, 3, p->name);
	if (p->size > 3)
		request_region (p->base + 3, p->size - 3, p->name);
	if (p->modes & PARPORT_MODE_ECP)
		request_region (p->base_hi, 3, p->name);

	if (p->irq != PARPORT_IRQ_NONE) {
		if (request_irq (p->irq, parport_gsc_interrupt,
				 0, p->name, p)) {
			printk (KERN_WARNING "%s: irq %d in use, "
				"resorting to polled operation\n",
				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 __initdata parport_count;

static int __init parport_init_chip(struct hp_device *d, struct pa_iodc_driver *dri)
{
	unsigned long port;
	int irq;

	irq = busdevice_alloc_irq(d); 

	if (!irq) {
	    printk("IRQ not found for parallel device at 0x%p\n", d->hpa);
	    return -ENODEV;
	}

	port = ((unsigned long) d->hpa) + PARPORT_GSC_OFFSET;
	
	/* 
	    some older machines with ASP-chip don't support the enhanced parport modes 
	*/
	if (!pdc_add_valid( (void *)(port+4))) {
	    /* Initialize bidirectional-mode (0x10) & data-tranfer-mode #1 (0x20) */
	    printk("%s: initialize bidirectional-mode.\n", __FUNCTION__);
	    parport_writeb ( (0x10 + 0x20), port + 4);
	} else {
	    printk("%s: enhanced parport-modes not supported.\n", __FUNCTION__);
	}
	
	if (parport_gsc_probe_port(port, 0, 
		    irq, /* PARPORT_IRQ_NONE */
		    PARPORT_DMA_NONE, NULL))
	    parport_count++;

	return 0;
}

static struct pa_iodc_driver parport_drivers_for[] __initdata = {
  {HPHW_FIO, 0x0, 0x0, 0x74, 0x0, 0,			/* 715/64 */
	DRIVER_CHECK_SVERSION + DRIVER_CHECK_HWTYPE,
	"parallel device", "HP 7xx - Series", (void *) parport_init_chip},
  { 0 }
};

int __init parport_gsc_init(void)
{
	parport_count = 0;
	
	register_driver(parport_drivers_for);

	return 0;
}


static int __init parport_gsc_init_module(void)
{	
	return !parport_gsc_init();
}

static void __exit parport_gsc_exit_module(void)
{
	struct parport *p = parport_enumerate(), *tmp;
	while (p) {
		tmp = p->next;
		if (p->modes & PARPORT_MODE_PCSPP) { 
			struct parport_gsc_private *priv = p->private_data;
			struct parport_operations *ops = p->ops;
			if (p->dma != PARPORT_DMA_NONE)
				free_dma(p->dma);
			if (p->irq != PARPORT_IRQ_NONE)
				free_irq(p->irq, p);
			release_region(p->base, 3);
			if (p->size > 3)
				release_region(p->base + 3, p->size - 3);
			if (p->modes & PARPORT_MODE_ECP)
				release_region(p->base_hi, 3);
			parport_proc_unregister(p);
			if (priv->dma_buf)
				pci_free_consistent(priv->dev, PAGE_SIZE,
						    priv->dma_buf,
						    priv->dma_handle);
			kfree (p->private_data);
			parport_unregister_port(p);
			kfree (ops); /* hope no-one cached it */
		}
		p = tmp;
	}
}

EXPORT_NO_SYMBOLS;

module_init(parport_gsc_init_module);
module_exit(parport_gsc_exit_module);
