text: /*
   *	drivers/pci/bus.c
   *
   * From setup-res.c, by:
   *	Dave Rusling (david.rusling@reo.mts.dec.com)
   *	David Mosberger (davidm@cs.arizona.edu)
   *	David Miller (davem@redhat.com)
   *	Ivan Kokshaysky (ink@jurassic.park.msu.ru)
   */
  #include <linux/module.h>
  #include <linux/kernel.h>
  #include <linux/pci.h>
  #include <linux/errno.h>
  #include <linux/ioport.h>
  #include <linux/proc_fs.h>
  #include <linux/init.h>
  
  #include "pci.h"
  
  /**
   * pci_bus_alloc_resource - allocate a resource from a parent bus
   * @bus: PCI bus
   * @res: resource to allocate
   * @size: size of resource to allocate
   * @align: alignment of resource to allocate
   * @min: minimum /proc/iomem address to allocate
   * @type_mask: IORESOURCE_* type flags
   * @alignf: resource alignment function
   * @alignf_data: data argument for resource alignment function
   *
   * Given the PCI bus a device resides on, the size, minimum address,
   * alignment and type, try to find an acceptable resource allocation
   * for a specific device resource.
   */
  int
  pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res,
  		resource_size_t size, resource_size_t align,
  		resource_size_t min, unsigned int type_mask,
  		void (*alignf)(void *, struct resource *, resource_size_t,
  				resource_size_t),
  		void *alignf_data)
  {
  	int i, ret = -ENOMEM;
  	resource_size_t max = -1;
  
  	type_mask |= IORESOURCE_IO | IORESOURCE_MEM;
  
  	/* don't allocate too high if the pref mem doesn't support 64bit*/
  	if (!(res->flags & IORESOURCE_MEM_64))
  		max = PCIBIOS_MAX_MEM_32;
  
  	for (i = 0; i < PCI_BUS_NUM_RESOURCES; i++) {
  		struct resource *r = bus->resource[i];
  		if (!r)
  			continue;
  
  		/* type_mask must match */
  		if ((res->flags ^ r->flags) & type_mask)
  			continue;
  
  		/* We cannot allocate a non-prefetching resource
  		   from a pre-fetching area */
  		if ((r->flags & IORESOURCE_PREFETCH) &&
  		    !(res->flags & IORESOURCE_PREFETCH))
  			continue;
  
  		/* Ok, try it out.. */
  		ret = allocate_resource(r, res, size,
  					r->start ? : min,
  					max, align,
  					alignf, alignf_data);
  		if (ret == 0)
  			break;
  	}
  	return ret;
  }
  
  /**
   * pci_bus_add_device - add a single device
   * @dev: device to add
   *
   * This adds a single pci device to the global
   * device list and adds sysfs and procfs entries
   */
  int pci_bus_add_device(struct pci_dev *dev)
  {
  	int retval;
  	retval = device_add(&dev->dev);
  	if (retval)
  		return retval;
  
  	dev->is_added = 1;
  	pci_proc_attach_device(dev);
  	pci_create_sysfs_dev_files(dev);
  	return 0;
  }
  
  /**
   * pci_bus_add_child - add a child bus
   * @bus: bus to add
   *
   * This adds sysfs entries for a single bus
   */
  int pci_bus_add_child(struct pci_bus *bus)
  {
  	int retval;
  
  	if (bus->bridge)
  		bus->dev.parent = bus->bridge;
  
  	retval = device_register(&bus->dev);
  	if (retval)
  		return retval;
  
  	bus->is_added = 1;
  
  	retval = device_create_file(&bus->dev, &dev_attr_cpuaffinity);
  	if (retval)
  		return retval;
  
  	retval = device_create_file(&bus->dev, &dev_attr_cpulistaffinity);
  
  	/* Create legacy_io and legacy_mem files for this bus */
  	pci_create_legacy_files(bus);
  
  	return retval;
  }
  
  /**
   * pci_bus_add_devices - insert newly discovered PCI devices
   * @bus: bus to check for new devices
   *
   * Add newly discovered PCI devices (which are on the bus->devices
   * list) to the global PCI device list, add the sysfs and procfs
   * entries.  Where a bridge is found, add the discovered bus to
   * the parents list of child buses, and recurse (breadth-first
   * to be compatible with 2.4)
   *
   * Call hotplug for each new devices.
   */
  void pci_bus_add_devices(const struct pci_bus *bus)
  {
  	struct pci_dev *dev;
  	struct pci_bus *child;
  	int retval;
  
  	list_for_each_entry(dev, &bus->devices, bus_list) {
  		/* Skip already-added devices */
  		if (dev->is_added)
  			continue;
  		retval = pci_bus_add_device(dev);
  		if (retval)
  			dev_err(&dev->dev, "Error adding device, continuing\n");
  	}
  
  	list_for_each_entry(dev, &bus->devices, bus_list) {
  		BUG_ON(!dev->is_added);
  
  		child = dev->subordinate;
  		/*
  		 * If there is an unattached subordinate bus, attach
  		 * it and then scan for unattached PCI devices.
  		 */
  		if (!child)
  			continue;
  		if (list_empty(&child->node)) {
  			down_write(&pci_bus_sem);
  			list_add_tail(&child->node, &dev->bus->children);
  			up_write(&pci_bus_sem);
  		}
  		pci_bus_add_devices(child);
  
  		/*
  		 * register the bus with sysfs as the parent is now
  		 * properly registered.
  		 */
  		if (child->is_added)
  			continue;
  		retval = pci_bus_add_child(child);
  		if (retval)
  			dev_err(&dev->dev, "Error adding bus, continuing\n");
  	}
  }
  
  void pci_enable_bridges(struct pci_bus *bus)
  {
  	struct pci_dev *dev;
  	int retval;
  
  	list_for_each_entry(dev, &bus->devices, bus_list) {
  		if (dev->subordinate) {
  			if (!pci_is_enabled(dev)) {
  				retval = pci_enable_device(dev);
  				pci_set_master(dev);
  			}
  			pci_enable_bridges(dev->subordinate);
  		}
  	}
  }
  
  /** pci_walk_bus - walk devices on/under bus, calling callback.
   *  @top      bus whose devices should be walked
   *  @cb       callback to be called for each device found
   *  @userdata arbitrary pointer to be passed to callback.
   *
   *  Walk the given bus, including any bridged devices
   *  on buses under this bus.  Call the provided callback
   *  on each device found.
   *
   *  We check the return of @cb each time. If it returns anything
   *  other than 0, we break out.
   *
   */
  void pci_walk_bus(struct pci_bus *top, int (*cb)(struct pci_dev *, void *),
  		  void *userdata)
  {
  	struct pci_dev *dev;
  	struct pci_bus *bus;
  	struct list_head *next;
  	int retval;
  
  	bus = top;
  	down_read(&pci_bus_sem);
  	next = top->devices.next;
  	for (;;) {
  		if (next == &bus->devices) {
  			/* end of this bus, go up or finish */
  			if (bus == top)
  				break;
  			next = bus->self->bus_list.next;
  			bus = bus->self->bus;
  			continue;
  		}
  		dev = list_entry(next, struct pci_dev, bus_list);
  		if (dev->subordinate) {
  			/* this is a pci-pci bridge, do its devices next */
  			next = dev->subordinate->devices.next;
  			bus = dev->subordinate;
  		} else
  			next = dev->bus_list.next;
  
  		/* Run device routines with the device locked */
  		down(&dev->dev.sem);
  		retval = cb(dev, userdata);
  		up(&dev->dev.sem);
  		if (retval)
  			break;
  	}
  	up_read(&pci_bus_sem);
  }
  
  EXPORT_SYMBOL(pci_bus_alloc_resource);
  EXPORT_SYMBOL_GPL(pci_bus_add_device);
  EXPORT_SYMBOL(pci_bus_add_devices);
  EXPORT_SYMBOL(pci_enable_bridges);
  