/*
   * IRQ domain support for SH INTC subsystem
   *
   * Copyright (C) 2012  Paul Mundt
   *
   * This file is subject to the terms and conditions of the GNU General Public
   * License.  See the file "COPYING" in the main directory of this archive
   * for more details.
   */
  #define pr_fmt(fmt) "intc: " fmt
  
  #include <linux/irqdomain.h>
  #include <linux/sh_intc.h>
  #include <linux/export.h>
  #include "internals.h"
  
  /**
   * intc_irq_domain_evt_xlate() - Generic xlate for vectored IRQs.
   *
   * This takes care of exception vector to hwirq translation through
   * by way of evt2irq() translation.
   *
   * Note: For platforms that use a flat vector space without INTEVT this
   * basically just mimics irq_domain_xlate_onecell() by way of a nopped
   * out evt2irq() implementation.
   */
  static int intc_evt_xlate(struct irq_domain *d, struct device_node *ctrlr,
  			  const u32 *intspec, unsigned int intsize,
  			  unsigned long *out_hwirq, unsigned int *out_type)
  {
  	if (WARN_ON(intsize < 1))
  		return -EINVAL;
  
  	*out_hwirq = evt2irq(intspec[0]);
  	*out_type = IRQ_TYPE_NONE;
  
  	return 0;
  }
  
  static const struct irq_domain_ops intc_evt_ops = {
  	.xlate		= intc_evt_xlate,
  };
  
  void __init intc_irq_domain_init(struct intc_desc_int *d,
  				 struct intc_hw_desc *hw)
  {
  	unsigned int irq_base, irq_end;
  
  	/*
  	 * Quick linear revmap check
  	 */
  	irq_base = evt2irq(hw->vectors[0].vect);
  	irq_end = evt2irq(hw->vectors[hw->nr_vectors - 1].vect);
  
  	/*
  	 * Linear domains have a hard-wired assertion that IRQs start at
  	 * 0 in order to make some performance optimizations. Lamely
  	 * restrict the linear case to these conditions here, taking the
  	 * tree penalty for linear cases with non-zero hwirq bases.
  	 */
  	if (irq_base == 0 && irq_end == (irq_base + hw->nr_vectors - 1))
  		d->domain = irq_domain_add_linear(NULL, hw->nr_vectors,
  						  &intc_evt_ops, NULL);
  	else
  		d->domain = irq_domain_add_tree(NULL, &intc_evt_ops, NULL);
  
  	BUG_ON(!d->domain);
  }