text: /*
   * Fake PCI Hot Plug Controller Driver
   *
   * Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
   * Copyright (C) 2003 IBM Corp.
   * Copyright (C) 2003 Rolf Eike Beer <eike-kernel@sf-tec.de>
   *
   * Based on ideas and code from:
   * 	Vladimir Kondratiev <vladimir.kondratiev@intel.com>
   *	Rolf Eike Beer <eike-kernel@sf-tec.de>
   *
   * All rights reserved.
   *
   * 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, version 2 of the License.
   *
   * Send feedback to <greg@kroah.com>
   */
  
  /*
   *
   * This driver will "emulate" removing PCI devices from the system.  If
   * the "power" file is written to with "0" then the specified PCI device
   * will be completely removed from the kernel.
   *
   * WARNING, this does NOT turn off the power to the PCI device.  This is
   * a "logical" removal, not a physical or electrical removal.
   *
   * Use this module at your own risk, you have been warned!
   *
   * Enabling PCI devices is left as an exercise for the reader...
   *
   */
  #include <linux/config.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/pci.h>
  #include <linux/init.h>
  #include <linux/string.h>
  #include <linux/slab.h>
  #include "pci_hotplug.h"
  #include "../pci.h"
  
  #if !defined(MODULE)
  	#define MY_NAME	"fakephp"
  #else
  	#define MY_NAME	THIS_MODULE->name
  #endif
  
  #define dbg(format, arg...)					\
  	do {							\
  		if (debug)					\
  			printk(KERN_DEBUG "%s: " format,	\
  				MY_NAME , ## arg); 		\
  	} while (0)
  #define err(format, arg...) printk(KERN_ERR "%s: " format, MY_NAME , ## arg)
  #define info(format, arg...) printk(KERN_INFO "%s: " format, MY_NAME , ## arg)
  
  #define DRIVER_AUTHOR	"Greg Kroah-Hartman <greg@kroah.com>"
  #define DRIVER_DESC	"Fake PCI Hot Plug Controller Driver"
  
  struct dummy_slot {
  	struct list_head node;
  	struct hotplug_slot *slot;
  	struct pci_dev *dev;
  };
  
  static int debug;
  static LIST_HEAD(slot_list);
  
  static int enable_slot (struct hotplug_slot *slot);
  static int disable_slot (struct hotplug_slot *slot);
  
  static struct hotplug_slot_ops dummy_hotplug_slot_ops = {
  	.owner			= THIS_MODULE,
  	.enable_slot		= enable_slot,
  	.disable_slot		= disable_slot,
  };
  
  static void dummy_release(struct hotplug_slot *slot)
  {
  	struct dummy_slot *dslot = slot->private;
  
  	list_del(&dslot->node);
  	kfree(dslot->slot->info);
  	kfree(dslot->slot);
  	pci_dev_put(dslot->dev);
  	kfree(dslot);
  }
  
  static int add_slot(struct pci_dev *dev)
  {
  	struct dummy_slot *dslot;
  	struct hotplug_slot *slot;
  	int retval = -ENOMEM;
  
  	slot = kmalloc(sizeof(struct hotplug_slot), GFP_KERNEL);
  	if (!slot)
  		goto error;
  	memset(slot, 0, sizeof(*slot));
  
  	slot->info = kmalloc(sizeof(struct hotplug_slot_info), GFP_KERNEL);
  	if (!slot->info)
  		goto error_slot;
  	memset(slot->info, 0, sizeof(struct hotplug_slot_info));
  
  	slot->info->power_status = 1;
  	slot->info->max_bus_speed = PCI_SPEED_UNKNOWN;
  	slot->info->cur_bus_speed = PCI_SPEED_UNKNOWN;
  
  	slot->name = &dev->dev.bus_id[0];
  	dbg("slot->name = %s\n", slot->name);
  
  	dslot = kmalloc(sizeof(struct dummy_slot), GFP_KERNEL);
  	if (!dslot)
  		goto error_info;
  
  	slot->ops = &dummy_hotplug_slot_ops;
  	slot->release = &dummy_release;
  	slot->private = dslot;
  
  	retval = pci_hp_register(slot);
  	if (retval) {
  		err("pci_hp_register failed with error %d\n", retval);
  		goto error_dslot;
  	}
  
  	dslot->slot = slot;
  	dslot->dev = pci_dev_get(dev);
  	list_add (&dslot->node, &slot_list);
  	return retval;
  
  error_dslot:
  	kfree(dslot);
  error_info:
  	kfree(slot->info);
  error_slot:
  	kfree(slot);
  error:
  	return retval;
  }
  
  static int __init pci_scan_buses(void)
  {
  	struct pci_dev *dev = NULL;
  	int retval = 0;
  
  	while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
  		retval = add_slot(dev);
  		if (retval) {
  			pci_dev_put(dev);
  			break;
  		}
  	}
  
  	return retval;
  }
  
  static void remove_slot(struct dummy_slot *dslot)
  {
  	int retval;
  
  	dbg("removing slot %s\n", dslot->slot->name);
  	retval = pci_hp_deregister(dslot->slot);
  	if (retval)
  		err("Problem unregistering a slot %s\n", dslot->slot->name);
  }
  
  /**
   * Rescan slot.
   * Tries hard not to re-enable already existing devices
   * also handles scanning of subfunctions
   *
   * @param temp   Device template. Should be set: bus and devfn.
   */
  static void pci_rescan_slot(struct pci_dev *temp)
  {
  	struct pci_bus *bus = temp->bus;
  	struct pci_dev *dev;
  	int func;
  	u8 hdr_type;
  	if (!pci_read_config_byte(temp, PCI_HEADER_TYPE, &hdr_type)) {
  		temp->hdr_type = hdr_type & 0x7f;
  		if (!pci_find_slot(bus->number, temp->devfn)) {
  			dev = pci_scan_single_device(bus, temp->devfn);
  			if (dev) {
  				dbg("New device on %s function %x:%x\n",
  					bus->name, temp->devfn >> 3,
  					temp->devfn & 7);
  				pci_bus_add_device(dev);
  				add_slot(dev);
  			}
  		}
  		/* multifunction device? */
  		if (!(hdr_type & 0x80))
  			return;
  
  		/* continue scanning for other functions */
  		for (func = 1, temp->devfn++; func < 8; func++, temp->devfn++) {
  			if (pci_read_config_byte(temp, PCI_HEADER_TYPE, &hdr_type))
  				continue;
  			temp->hdr_type = hdr_type & 0x7f;
  
  			if (!pci_find_slot(bus->number, temp->devfn)) {
  				dev = pci_scan_single_device(bus, temp->devfn);
  				if (dev) {
  					dbg("New device on %s function %x:%x\n",
  						bus->name, temp->devfn >> 3,
  						temp->devfn & 7);
  					pci_bus_add_device(dev);
  					add_slot(dev);
  				}
  			}
  		}
  	}
  }
  
  
  /**
   * Rescan PCI bus.
   * call pci_rescan_slot for each possible function of the bus
   *
   * @param bus
   */
  static void pci_rescan_bus(const struct pci_bus *bus)
  {
  	unsigned int devfn;
  	struct pci_dev *dev;
  	dev = kmalloc(sizeof(struct pci_dev), GFP_KERNEL);
  	if (!dev)
  		return;
  
  	memset(dev, 0, sizeof(dev));
  	dev->bus = (struct pci_bus*)bus;
  	dev->sysdata = bus->sysdata;
  	for (devfn = 0; devfn < 0x100; devfn += 8) {
  		dev->devfn = devfn;
  		pci_rescan_slot(dev);
  	}
  	kfree(dev);
  }
  
  /* recursively scan all buses */
  static void pci_rescan_buses(const struct list_head *list)
  {
  	const struct list_head *l;
  	list_for_each(l,list) {
  		const struct pci_bus *b = pci_bus_b(l);
  		pci_rescan_bus(b);
  		pci_rescan_buses(&b->children);
  	}
  }
  
  /* initiate rescan of all pci buses */
  static inline void pci_rescan(void) {
  	pci_rescan_buses(&pci_root_buses);
  }
  
  
  static int enable_slot(struct hotplug_slot *hotplug_slot)
  {
  	/* mis-use enable_slot for rescanning of the pci bus */
  	pci_rescan();
  	return -ENODEV;
  }
  
  /* find the hotplug_slot for the pci_dev */
  static struct hotplug_slot *get_slot_from_dev(struct pci_dev *dev)
  {
  	struct dummy_slot *dslot;
  
  	list_for_each_entry(dslot, &slot_list, node) {
  		if (dslot->dev == dev)
  			return dslot->slot;
  	}
  	return NULL;
  }
  
  
  static int disable_slot(struct hotplug_slot *slot)
  {
  	struct dummy_slot *dslot;
  	struct hotplug_slot *hslot;
  	struct pci_dev *dev;
  	int func;
  
  	if (!slot)
  		return -ENODEV;
  	dslot = slot->private;
  
  	dbg("%s - physical_slot = %s\n", __FUNCTION__, slot->name);
  
  	/* don't disable bridged devices just yet, we can't handle them easily... */
  	if (dslot->dev->subordinate) {
  		err("Can't remove PCI devices with other PCI devices behind it yet.\n");
  		return -ENODEV;
  	}
  	/* search for subfunctions and disable them first */
  	if (!(dslot->dev->devfn & 7)) {
  		for (func = 1; func < 8; func++) {
  			dev = pci_find_slot(dslot->dev->bus->number,
  					dslot->dev->devfn + func);
  			if (dev) {
  				hslot = get_slot_from_dev(dev);
  				if (hslot)
  					disable_slot(hslot);
  				else {
  					err("Hotplug slot not found for subfunction of PCI device\n");
  					return -ENODEV;
  				}
  			} else
  				dbg("No device in slot found\n");
  		}
  	}
  
  	/* remove the device from the pci core */
  	pci_remove_bus_device(dslot->dev);
  
  	/* blow away this sysfs entry and other parts. */
  	remove_slot(dslot);
  
  	return 0;
  }
  
  static void cleanup_slots (void)
  {
  	struct list_head *tmp;
  	struct list_head *next;
  	struct dummy_slot *dslot;
  
  	list_for_each_safe (tmp, next, &slot_list) {
  		dslot = list_entry (tmp, struct dummy_slot, node);
  		remove_slot(dslot);
  	}
  	
  }
  
  static int __init dummyphp_init(void)
  {
  	info(DRIVER_DESC "\n");
  
  	return pci_scan_buses();
  }
  
  
  static void __exit dummyphp_exit(void)
  {
  	cleanup_slots();
  }
  
  module_init(dummyphp_init);
  module_exit(dummyphp_exit);
  
  MODULE_AUTHOR(DRIVER_AUTHOR);
  MODULE_DESCRIPTION(DRIVER_DESC);
  MODULE_LICENSE("GPL");
  module_param(debug, bool, S_IRUGO | S_IWUSR);
  MODULE_PARM_DESC(debug, "Debugging mode enabled or not");
  
  