text: /*
   * Routines for tracking a legacy ISA bridge
   *
   * Copyrigh 2007 Benjamin Herrenschmidt <benh@kernel.crashing.org>, IBM Corp.
   *
   * Some bits and pieces moved over from pci_64.c
   *
   * Copyrigh 2003 Anton Blanchard <anton@au.ibm.com>, IBM Corp.
   *
   *      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.
   */
  
  #define DEBUG
  
  #include <linux/kernel.h>
  #include <linux/pci.h>
  #include <linux/string.h>
  #include <linux/export.h>
  #include <linux/init.h>
  #include <linux/mm.h>
  #include <linux/notifier.h>
  
  #include <asm/processor.h>
  #include <asm/io.h>
  #include <asm/prom.h>
  #include <asm/pci-bridge.h>
  #include <asm/machdep.h>
  #include <asm/ppc-pci.h>
  
  unsigned long isa_io_base;	/* NULL if no ISA bus */
  EXPORT_SYMBOL(isa_io_base);
  
  /* Cached ISA bridge dev. */
  static struct device_node *isa_bridge_devnode;
  struct pci_dev *isa_bridge_pcidev;
  EXPORT_SYMBOL_GPL(isa_bridge_pcidev);
  
  #define ISA_SPACE_MASK 0x1
  #define ISA_SPACE_IO 0x1
  
  static void pci_process_ISA_OF_ranges(struct device_node *isa_node,
  				      unsigned long phb_io_base_phys)
  {
  	/* We should get some saner parsing here and remove these structs */
  	struct pci_address {
  		u32 a_hi;
  		u32 a_mid;
  		u32 a_lo;
  	};
  
  	struct isa_address {
  		u32 a_hi;
  		u32 a_lo;
  	};
  
  	struct isa_range {
  		struct isa_address isa_addr;
  		struct pci_address pci_addr;
  		unsigned int size;
  	};
  
  	const struct isa_range *range;
  	unsigned long pci_addr;
  	unsigned int isa_addr;
  	unsigned int size;
  	int rlen = 0;
  
  	range = of_get_property(isa_node, "ranges", &rlen);
  	if (range == NULL || (rlen < sizeof(struct isa_range)))
  		goto inval_range;
  
  	/* From "ISA Binding to 1275"
  	 * The ranges property is laid out as an array of elements,
  	 * each of which comprises:
  	 *   cells 0 - 1:	an ISA address
  	 *   cells 2 - 4:	a PCI address
  	 *			(size depending on dev->n_addr_cells)
  	 *   cell 5:		the size of the range
  	 */
  	if ((range->isa_addr.a_hi & ISA_SPACE_MASK) != ISA_SPACE_IO) {
  		range++;
  		rlen -= sizeof(struct isa_range);
  		if (rlen < sizeof(struct isa_range))
  			goto inval_range;
  	}
  	if ((range->isa_addr.a_hi & ISA_SPACE_MASK) != ISA_SPACE_IO)
  		goto inval_range;
  
  	isa_addr = range->isa_addr.a_lo;
  	pci_addr = (unsigned long) range->pci_addr.a_mid << 32 |
  		range->pci_addr.a_lo;
  
  	/* Assume these are both zero. Note: We could fix that and
  	 * do a proper parsing instead ... oh well, that will do for
  	 * now as nobody uses fancy mappings for ISA bridges
  	 */
  	if ((pci_addr != 0) || (isa_addr != 0)) {
  		printk(KERN_ERR "unexpected isa to pci mapping: %s\n",
  		       __func__);
  		return;
  	}
  
  	/* Align size and make sure it's cropped to 64K */
  	size = PAGE_ALIGN(range->size);
  	if (size > 0x10000)
  		size = 0x10000;
  
  	__ioremap_at(phb_io_base_phys, (void *)ISA_IO_BASE,
  		     size, _PAGE_NO_CACHE|_PAGE_GUARDED);
  	return;
  
  inval_range:
  	printk(KERN_ERR "no ISA IO ranges or unexpected isa range, "
  	       "mapping 64k\n");
  	__ioremap_at(phb_io_base_phys, (void *)ISA_IO_BASE,
  		     0x10000, _PAGE_NO_CACHE|_PAGE_GUARDED);
  }
  
  
  /**
   * isa_bridge_find_early - Find and map the ISA IO space early before
   *                         main PCI discovery. This is optionally called by
   *                         the arch code when adding PCI PHBs to get early
   *                         access to ISA IO ports
   */
  void __init isa_bridge_find_early(struct pci_controller *hose)
  {
  	struct device_node *np, *parent = NULL, *tmp;
  
  	/* If we already have an ISA bridge, bail off */
  	if (isa_bridge_devnode != NULL)
  		return;
  
  	/* For each "isa" node in the system. Note : we do a search by
  	 * type and not by name. It might be better to do by name but that's
  	 * what the code used to do and I don't want to break too much at
  	 * once. We can look into changing that separately
  	 */
  	for_each_node_by_type(np, "isa") {
  		/* Look for our hose being a parent */
  		for (parent = of_get_parent(np); parent;) {
  			if (parent == hose->dn) {
  				of_node_put(parent);
  				break;
  			}
  			tmp = parent;
  			parent = of_get_parent(parent);
  			of_node_put(tmp);
  		}
  		if (parent != NULL)
  			break;
  	}
  	if (np == NULL)
  		return;
  	isa_bridge_devnode = np;
  
  	/* Now parse the "ranges" property and setup the ISA mapping */
  	pci_process_ISA_OF_ranges(np, hose->io_base_phys);
  
  	/* Set the global ISA io base to indicate we have an ISA bridge */
  	isa_io_base = ISA_IO_BASE;
  
  	pr_debug("ISA bridge (early) is %s\n", np->full_name);
  }
  
  /**
   * isa_bridge_find_late - Find and map the ISA IO space upon discovery of
   *                        a new ISA bridge
   */
  static void isa_bridge_find_late(struct pci_dev *pdev,
  				 struct device_node *devnode)
  {
  	struct pci_controller *hose = pci_bus_to_host(pdev->bus);
  
  	/* Store ISA device node and PCI device */
  	isa_bridge_devnode = of_node_get(devnode);
  	isa_bridge_pcidev = pdev;
  
  	/* Now parse the "ranges" property and setup the ISA mapping */
  	pci_process_ISA_OF_ranges(devnode, hose->io_base_phys);
  
  	/* Set the global ISA io base to indicate we have an ISA bridge */
  	isa_io_base = ISA_IO_BASE;
  
  	pr_debug("ISA bridge (late) is %s on %s\n",
  		 devnode->full_name, pci_name(pdev));
  }
  
  /**
   * isa_bridge_remove - Remove/unmap an ISA bridge
   */
  static void isa_bridge_remove(void)
  {
  	pr_debug("ISA bridge removed !\n");
  
  	/* Clear the global ISA io base to indicate that we have no more
  	 * ISA bridge. Note that drivers don't quite handle that, though
  	 * we should probably do something about it. But do we ever really
  	 * have ISA bridges being removed on machines using legacy devices ?
  	 */
  	isa_io_base = ISA_IO_BASE;
  
  	/* Clear references to the bridge */
  	of_node_put(isa_bridge_devnode);
  	isa_bridge_devnode = NULL;
  	isa_bridge_pcidev = NULL;
  
  	/* Unmap the ISA area */
  	__iounmap_at((void *)ISA_IO_BASE, 0x10000);
  }
  
  /**
   * isa_bridge_notify - Get notified of PCI devices addition/removal
   */
  static int isa_bridge_notify(struct notifier_block *nb, unsigned long action,
  			     void *data)
  {
  	struct device *dev = data;
  	struct pci_dev *pdev = to_pci_dev(dev);
  	struct device_node *devnode = pci_device_to_OF_node(pdev);
  
  	switch(action) {
  	case BUS_NOTIFY_ADD_DEVICE:
  		/* Check if we have an early ISA device, without PCI dev */
  		if (isa_bridge_devnode && isa_bridge_devnode == devnode &&
  		    !isa_bridge_pcidev) {
  			pr_debug("ISA bridge PCI attached: %s\n",
  				 pci_name(pdev));
  			isa_bridge_pcidev = pdev;
  		}
  
  		/* Check if we have no ISA device, and this happens to be one,
  		 * register it as such if it has an OF device
  		 */
  		if (!isa_bridge_devnode && devnode && devnode->type &&
  		    !strcmp(devnode->type, "isa"))
  			isa_bridge_find_late(pdev, devnode);
  
  		return 0;
  	case BUS_NOTIFY_DEL_DEVICE:
  		/* Check if this our existing ISA device */
  		if (pdev == isa_bridge_pcidev ||
  		    (devnode && devnode == isa_bridge_devnode))
  			isa_bridge_remove();
  		return 0;
  	}
  	return 0;
  }
  
  static struct notifier_block isa_bridge_notifier = {
  	.notifier_call = isa_bridge_notify
  };
  
  /**
   * isa_bridge_init - register to be notified of ISA bridge addition/removal
   *
   */
  static int __init isa_bridge_init(void)
  {
  	bus_register_notifier(&pci_bus_type, &isa_bridge_notifier);
  	return 0;
  }
  arch_initcall(isa_bridge_init);
  