/*
   * Interrupt management for most GSC and related devices.
   *
   * (c) Copyright 1999 Alex deVries for The Puffin Group
   * (c) Copyright 1999 Grant Grundler for Hewlett-Packard
   * (c) Copyright 1999 Matthew Wilcox
   * (c) Copyright 2000 Helge Deller
   * (c) Copyright 2001 Matthew Wilcox for Hewlett-Packard
   *
   *	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.
   */
  
  #include <linux/bitops.h>
  #include <linux/errno.h>
  #include <linux/init.h>
  #include <linux/interrupt.h>
  #include <linux/ioport.h>
  #include <linux/module.h>
  #include <linux/types.h>
  
  #include <asm/hardware.h>
  #include <asm/io.h>
  
  #include "gsc.h"
  
  #undef DEBUG
  
  #ifdef DEBUG
  #define DEBPRINTK printk
  #else
  #define DEBPRINTK(x,...)
  #endif
  
  int gsc_alloc_irq(struct gsc_irq *i)
  {
  	int irq = txn_alloc_irq(GSC_EIM_WIDTH);
  	if (irq < 0) {
  		printk("cannot get irq
  ");
  		return irq;
  	}
  
  	i->txn_addr = txn_alloc_addr(irq);
  	i->txn_data = txn_alloc_data(irq);
  	i->irq = irq;
  
  	return irq;
  }
  
  int gsc_claim_irq(struct gsc_irq *i, int irq)
  {
  	int c = irq;
  
  	irq += CPU_IRQ_BASE; /* virtualize the IRQ first */
  
  	irq = txn_claim_irq(irq);
  	if (irq < 0) {
  		printk("cannot claim irq %d
  ", c);
  		return irq;
  	}
  
  	i->txn_addr = txn_alloc_addr(irq);
  	i->txn_data = txn_alloc_data(irq);
  	i->irq = irq;
  
  	return irq;
  }
  
  EXPORT_SYMBOL(gsc_alloc_irq);
  EXPORT_SYMBOL(gsc_claim_irq);
  
  /* Common interrupt demultiplexer used by Asp, Lasi & Wax.  */
  irqreturn_t gsc_asic_intr(int gsc_asic_irq, void *dev)
  {
  	unsigned long irr;
  	struct gsc_asic *gsc_asic = dev;
  
  	irr = gsc_readl(gsc_asic->hpa + OFFSET_IRR);
  	if (irr == 0)
  		return IRQ_NONE;
  
  	DEBPRINTK("%s intr, mask=0x%x
  ", gsc_asic->name, irr);
  
  	do {
  		int local_irq = __ffs(irr);
  		unsigned int irq = gsc_asic->global_irq[local_irq];
  		generic_handle_irq(irq);
  		irr &= ~(1 << local_irq);
  	} while (irr);
  
  	return IRQ_HANDLED;
  }
  
  int gsc_find_local_irq(unsigned int irq, int *global_irqs, int limit)
  {
  	int local_irq;
  
  	for (local_irq = 0; local_irq < limit; local_irq++) {
  		if (global_irqs[local_irq] == irq)
  			return local_irq;
  	}
  
  	return NO_IRQ;
  }
  
  static void gsc_asic_mask_irq(struct irq_data *d)
  {
  	struct gsc_asic *irq_dev = irq_data_get_irq_chip_data(d);
  	int local_irq = gsc_find_local_irq(d->irq, irq_dev->global_irq, 32);
  	u32 imr;
  
  	DEBPRINTK(KERN_DEBUG "%s(%d) %s: IMR 0x%x
  ", __func__, d->irq,
  			irq_dev->name, imr);
  
  	/* Disable the IRQ line by clearing the bit in the IMR */
  	imr = gsc_readl(irq_dev->hpa + OFFSET_IMR);
  	imr &= ~(1 << local_irq);
  	gsc_writel(imr, irq_dev->hpa + OFFSET_IMR);
  }
  
  static void gsc_asic_unmask_irq(struct irq_data *d)
  {
  	struct gsc_asic *irq_dev = irq_data_get_irq_chip_data(d);
  	int local_irq = gsc_find_local_irq(d->irq, irq_dev->global_irq, 32);
  	u32 imr;
  
  	DEBPRINTK(KERN_DEBUG "%s(%d) %s: IMR 0x%x
  ", __func__, d->irq,
  			irq_dev->name, imr);
  
  	/* Enable the IRQ line by setting the bit in the IMR */
  	imr = gsc_readl(irq_dev->hpa + OFFSET_IMR);
  	imr |= 1 << local_irq;
  	gsc_writel(imr, irq_dev->hpa + OFFSET_IMR);
  	/*
  	 * FIXME: read IPR to make sure the IRQ isn't already pending.
  	 *   If so, we need to read IRR and manually call do_irq().
  	 */
  }
  
  static struct irq_chip gsc_asic_interrupt_type = {
  	.name		=	"GSC-ASIC",
  	.irq_unmask	=	gsc_asic_unmask_irq,
  	.irq_mask	=	gsc_asic_mask_irq,
  };
  
  int gsc_assign_irq(struct irq_chip *type, void *data)
  {
  	static int irq = GSC_IRQ_BASE;
  
  	if (irq > GSC_IRQ_MAX)
  		return NO_IRQ;
  
  	irq_set_chip_and_handler(irq, type, handle_simple_irq);
  	irq_set_chip_data(irq, data);
  
  	return irq++;
  }
  
  void gsc_asic_assign_irq(struct gsc_asic *asic, int local_irq, int *irqp)
  {
  	int irq = asic->global_irq[local_irq];
  	
  	if (irq <= 0) {
  		irq = gsc_assign_irq(&gsc_asic_interrupt_type, asic);
  		if (irq == NO_IRQ)
  			return;
  
  		asic->global_irq[local_irq] = irq;
  	}
  	*irqp = irq;
  }
  
  struct gsc_fixup_struct {
  	void (*choose_irq)(struct parisc_device *, void *);
  	void *ctrl;
  };
  
  static int gsc_fixup_irqs_callback(struct device *dev, void *data)
  {
  	struct parisc_device *padev = to_parisc_device(dev);
  	struct gsc_fixup_struct *gf = data;
  
  	/* work-around for 715/64 and others which have parent
  	   at path [5] and children at path [5/0/x] */
  	if (padev->id.hw_type == HPHW_FAULTY)
  		gsc_fixup_irqs(padev, gf->ctrl, gf->choose_irq);
  	gf->choose_irq(padev, gf->ctrl);
  
  	return 0;
  }
  
  void gsc_fixup_irqs(struct parisc_device *parent, void *ctrl,
  			void (*choose_irq)(struct parisc_device *, void *))
  {
  	struct gsc_fixup_struct data = {
  		.choose_irq	= choose_irq,
  		.ctrl		= ctrl,
  	};
  
  	device_for_each_child(&parent->dev, &data, gsc_fixup_irqs_callback);
  }
  
  int gsc_common_setup(struct parisc_device *parent, struct gsc_asic *gsc_asic)
  {
  	struct resource *res;
  	int i;
  
  	gsc_asic->gsc = parent;
  
  	/* Initialise local irq -> global irq mapping */
  	for (i = 0; i < 32; i++) {
  		gsc_asic->global_irq[i] = NO_IRQ;
  	}
  
  	/* allocate resource region */
  	res = request_mem_region(gsc_asic->hpa, 0x100000, gsc_asic->name);
  	if (res) {
  		res->flags = IORESOURCE_MEM; 	/* do not mark it busy ! */
  	}
  
  #if 0
  	printk(KERN_WARNING "%s IRQ %d EIM 0x%x", gsc_asic->name,
  			parent->irq, gsc_asic->eim);
  	if (gsc_readl(gsc_asic->hpa + OFFSET_IMR))
  		printk("  IMR is non-zero! (0x%x)",
  				gsc_readl(gsc_asic->hpa + OFFSET_IMR));
  	printk("
  ");
  #endif
  
  	return 0;
  }
  
  extern struct parisc_driver lasi_driver;
  extern struct parisc_driver asp_driver;
  extern struct parisc_driver wax_driver;
  
  void __init gsc_init(void)
  {
  #ifdef CONFIG_GSC_LASI
  	register_parisc_driver(&lasi_driver);
  	register_parisc_driver(&asp_driver);
  #endif
  #ifdef CONFIG_GSC_WAX
  	register_parisc_driver(&wax_driver);
  #endif
  }