drivers/pci/hotplug/fakephp.c - linux - Git at Google

 /*
  * 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/kernel.h>
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/pci_hotplug.h>
 #include <linux/init.h>
 #include <linux/string.h>
 #include <linux/slab.h>
 #include <linux/workqueue.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;
 	struct work_struct remove_work;
 	unsigned long removed;
 };

 static int debug;
 static int dup_slots;
 static LIST_HEAD(slot_list);
 static struct workqueue_struct *dummyphp_wq;

 static void pci_rescan_worker(struct work_struct *work);
 static DECLARE_WORK(pci_rescan_work, pci_rescan_worker);

 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);
 }

 #define SLOT_NAME_SIZE	8

 static int add_slot(struct pci_dev *dev)
 {
 	struct dummy_slot *dslot;
 	struct hotplug_slot *slot;
 	char name[SLOT_NAME_SIZE];
 	int retval = -ENOMEM;
 	static int count = 1;

 	slot = kzalloc(sizeof(struct hotplug_slot), GFP_KERNEL);
 	if (!slot)
 		goto error;

 	slot->info = kzalloc(sizeof(struct hotplug_slot_info), GFP_KERNEL);
 	if (!slot->info)
 		goto error_slot;

 	slot->info->power_status = 1;
 	slot->info->max_bus_speed = PCI_SPEED_UNKNOWN;
 	slot->info->cur_bus_speed = PCI_SPEED_UNKNOWN;

 	dslot = kzalloc(sizeof(struct dummy_slot), GFP_KERNEL);
 	if (!dslot)
 		goto error_info;

 	if (dup_slots)
 		snprintf(name, SLOT_NAME_SIZE, "fake");
 	else
 		snprintf(name, SLOT_NAME_SIZE, "fake%d", count++);
 	dbg("slot->name = %s\n", name);
 	slot->ops = &dummy_hotplug_slot_ops;
 	slot->release = &dummy_release;
 	slot->private = dslot;

 	retval = pci_hp_register(slot, dev->bus, PCI_SLOT(dev->devfn), name);
 	if (retval) {
 		err("pci_hp_register failed with error %d\n", retval);
 		goto error_dslot;
 	}

 	dbg("slot->name = %s\n", hotplug_slot_name(slot));
 	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 lastslot = 0;

 	while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
 		if (PCI_FUNC(dev->devfn) > 0 &&
 				lastslot == PCI_SLOT(dev->devfn))
 			continue;
 		lastslot = PCI_SLOT(dev->devfn);
 		add_slot(dev);
 	}

 	return 0;
 }

 static void remove_slot(struct dummy_slot *dslot)
 {
 	int retval;

 	dbg("removing slot %s\n", hotplug_slot_name(dslot->slot));
 	retval = pci_hp_deregister(dslot->slot);
 	if (retval)
 		err("Problem unregistering a slot %s\n",
 			hotplug_slot_name(dslot->slot));
 }

 /* called from the single-threaded workqueue handler to remove a slot */
 static void remove_slot_worker(struct work_struct *work)
 {
 	struct dummy_slot *dslot =
 		container_of(work, struct dummy_slot, remove_work);
 	remove_slot(dslot);
 }

 /**
  * pci_rescan_slot - Rescan slot
  * @temp: Device template. Should be set: bus and devfn.
  *
  * Tries hard not to re-enable already existing devices;
  * also handles scanning of subfunctions.
  */
 static int pci_rescan_slot(struct pci_dev *temp)
 {
 	struct pci_bus *bus = temp->bus;
 	struct pci_dev *dev;
 	int func;
 	u8 hdr_type;
 	int count = 0;

 	if (!pci_read_config_byte(temp, PCI_HEADER_TYPE, &hdr_type)) {
 		temp->hdr_type = hdr_type & 0x7f;
 		if ((dev = pci_get_slot(bus, temp->devfn)) != NULL)
 			pci_dev_put(dev);
 		else {
 			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);
 				count++;
 			}
 		}
 		/* multifunction device? */
 		if (!(hdr_type & 0x80))
 			return count;

 		/* 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 ((dev = pci_get_slot(bus, temp->devfn)) != NULL)
 				pci_dev_put(dev);
 			else {
 				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);
 					count++;
 				}
 			}
 		}
 	}

 	return count;
 }


 /**
  * pci_rescan_bus - Rescan PCI bus
  * @bus: the PCI bus to rescan
  *
  * Call pci_rescan_slot for each possible function of the bus.
  */
 static void pci_rescan_bus(const struct pci_bus *bus)
 {
 	unsigned int devfn;
 	struct pci_dev *dev;
 	int retval;
 	int found = 0;
 	dev = alloc_pci_dev();
 	if (!dev)
 		return;

 	dev->bus = (struct pci_bus*)bus;
 	dev->sysdata = bus->sysdata;
 	for (devfn = 0; devfn < 0x100; devfn += 8) {
 		dev->devfn = devfn;
 		found += pci_rescan_slot(dev);
 	}

 	if (found) {
 		pci_bus_assign_resources(bus);
 		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");
 			else
 				add_slot(dev);
 		}
 		pci_bus_add_devices(bus);
 	}
 	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);
 }

 /* called from the single-threaded workqueue handler to rescan all pci buses */
 static void pci_rescan_worker(struct work_struct *work)
 {
 	pci_rescan();
 }

 static int enable_slot(struct hotplug_slot *hotplug_slot)
 {
 	/* mis-use enable_slot for rescanning of the pci bus */
 	cancel_work_sync(&pci_rescan_work);
 	queue_work(dummyphp_wq, &pci_rescan_work);
 	return 0;
 }

 static int disable_slot(struct hotplug_slot *slot)
 {
 	struct dummy_slot *dslot;
 	struct pci_dev *dev;
 	int func;

 	if (!slot)
 		return -ENODEV;
 	dslot = slot->private;

 	dbg("%s - physical_slot = %s\n", __func__, hotplug_slot_name(slot));

 	for (func = 7; func >= 0; func--) {
 		dev = pci_get_slot(dslot->dev->bus, dslot->dev->devfn + func);
 		if (!dev)
 			continue;

 		if (test_and_set_bit(0, &dslot->removed)) {
 			dbg("Slot already scheduled for removal\n");
 			pci_dev_put(dev);
 			return -ENODEV;
 		}

 		/* remove the device from the pci core */
 		pci_remove_bus_device(dev);

 		/* queue work item to blow away this sysfs entry and other
 		 * parts.
 		 */
 		INIT_WORK(&dslot->remove_work, remove_slot_worker);
 		queue_work(dummyphp_wq, &dslot->remove_work);

 		pci_dev_put(dev);
 	}
 	return 0;
 }

 static void cleanup_slots (void)
 {
 	struct list_head *tmp;
 	struct list_head *next;
 	struct dummy_slot *dslot;

 	destroy_workqueue(dummyphp_wq);
 	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");

 	dummyphp_wq = create_singlethread_workqueue(MY_NAME);
 	if (!dummyphp_wq)
 		return -ENOMEM;

 	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");
 module_param(dup_slots, bool, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(dup_slots, "Force duplicate slot names for debugging");
	/*
	* 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/kernel.h>
	#include <linux/module.h>
	#include <linux/pci.h>
	#include <linux/pci_hotplug.h>
	#include <linux/init.h>
	#include <linux/string.h>
	#include <linux/slab.h>
	#include <linux/workqueue.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;
	struct work_struct remove_work;
	unsigned long removed;
	};

	static int debug;
	static int dup_slots;
	static LIST_HEAD(slot_list);
	static struct workqueue_struct *dummyphp_wq;

	static void pci_rescan_worker(struct work_struct *work);
	static DECLARE_WORK(pci_rescan_work, pci_rescan_worker);

	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);
	}

	#define SLOT_NAME_SIZE 8

	static int add_slot(struct pci_dev *dev)
	{
	struct dummy_slot *dslot;
	struct hotplug_slot *slot;
	char name[SLOT_NAME_SIZE];
	int retval = -ENOMEM;
	static int count = 1;

	slot = kzalloc(sizeof(struct hotplug_slot), GFP_KERNEL);
	if (!slot)
	goto error;

	slot->info = kzalloc(sizeof(struct hotplug_slot_info), GFP_KERNEL);
	if (!slot->info)
	goto error_slot;

	slot->info->power_status = 1;
	slot->info->max_bus_speed = PCI_SPEED_UNKNOWN;
	slot->info->cur_bus_speed = PCI_SPEED_UNKNOWN;

	dslot = kzalloc(sizeof(struct dummy_slot), GFP_KERNEL);
	if (!dslot)
	goto error_info;

	if (dup_slots)
	snprintf(name, SLOT_NAME_SIZE, "fake");
	else
	snprintf(name, SLOT_NAME_SIZE, "fake%d", count++);
	dbg("slot->name = %s\n", name);
	slot->ops = &dummy_hotplug_slot_ops;
	slot->release = &dummy_release;
	slot->private = dslot;

	retval = pci_hp_register(slot, dev->bus, PCI_SLOT(dev->devfn), name);
	if (retval) {
	err("pci_hp_register failed with error %d\n", retval);
	goto error_dslot;
	}

	dbg("slot->name = %s\n", hotplug_slot_name(slot));
	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 lastslot = 0;

	while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
	if (PCI_FUNC(dev->devfn) > 0 &&
	lastslot == PCI_SLOT(dev->devfn))
	continue;
	lastslot = PCI_SLOT(dev->devfn);
	add_slot(dev);
	}

	return 0;
	}

	static void remove_slot(struct dummy_slot *dslot)
	{
	int retval;

	dbg("removing slot %s\n", hotplug_slot_name(dslot->slot));
	retval = pci_hp_deregister(dslot->slot);
	if (retval)
	err("Problem unregistering a slot %s\n",
	hotplug_slot_name(dslot->slot));
	}

	/* called from the single-threaded workqueue handler to remove a slot */
	static void remove_slot_worker(struct work_struct *work)
	{
	struct dummy_slot *dslot =
	container_of(work, struct dummy_slot, remove_work);
	remove_slot(dslot);
	}

	/**
	* pci_rescan_slot - Rescan slot
	* @temp: Device template. Should be set: bus and devfn.
	*
	* Tries hard not to re-enable already existing devices;
	* also handles scanning of subfunctions.
	*/
	static int pci_rescan_slot(struct pci_dev *temp)
	{
	struct pci_bus *bus = temp->bus;
	struct pci_dev *dev;
	int func;
	u8 hdr_type;
	int count = 0;

	if (!pci_read_config_byte(temp, PCI_HEADER_TYPE, &hdr_type)) {
	temp->hdr_type = hdr_type & 0x7f;
	if ((dev = pci_get_slot(bus, temp->devfn)) != NULL)
	pci_dev_put(dev);
	else {
	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);
	count++;
	}
	}
	/* multifunction device? */
	if (!(hdr_type & 0x80))
	return count;

	/* 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 ((dev = pci_get_slot(bus, temp->devfn)) != NULL)
	pci_dev_put(dev);
	else {
	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);
	count++;
	}
	}
	}
	}

	return count;
	}


	/**
	* pci_rescan_bus - Rescan PCI bus
	* @bus: the PCI bus to rescan
	*
	* Call pci_rescan_slot for each possible function of the bus.
	*/
	static void pci_rescan_bus(const struct pci_bus *bus)
	{
	unsigned int devfn;
	struct pci_dev *dev;
	int retval;
	int found = 0;
	dev = alloc_pci_dev();
	if (!dev)
	return;

	dev->bus = (struct pci_bus*)bus;
	dev->sysdata = bus->sysdata;
	for (devfn = 0; devfn < 0x100; devfn += 8) {
	dev->devfn = devfn;
	found += pci_rescan_slot(dev);
	}

	if (found) {
	pci_bus_assign_resources(bus);
	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");
	else
	add_slot(dev);
	}
	pci_bus_add_devices(bus);
	}
	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);
	}

	/* called from the single-threaded workqueue handler to rescan all pci buses */
	static void pci_rescan_worker(struct work_struct *work)
	{
	pci_rescan();
	}

	static int enable_slot(struct hotplug_slot *hotplug_slot)
	{
	/* mis-use enable_slot for rescanning of the pci bus */
	cancel_work_sync(&pci_rescan_work);
	queue_work(dummyphp_wq, &pci_rescan_work);
	return 0;
	}

	static int disable_slot(struct hotplug_slot *slot)
	{
	struct dummy_slot *dslot;
	struct pci_dev *dev;
	int func;

	if (!slot)
	return -ENODEV;
	dslot = slot->private;

	dbg("%s - physical_slot = %s\n", __func__, hotplug_slot_name(slot));

	for (func = 7; func >= 0; func--) {
	dev = pci_get_slot(dslot->dev->bus, dslot->dev->devfn + func);
	if (!dev)
	continue;

	if (test_and_set_bit(0, &dslot->removed)) {
	dbg("Slot already scheduled for removal\n");
	pci_dev_put(dev);
	return -ENODEV;
	}

	/* remove the device from the pci core */
	pci_remove_bus_device(dev);

	/* queue work item to blow away this sysfs entry and other
	* parts.
	*/
	INIT_WORK(&dslot->remove_work, remove_slot_worker);
	queue_work(dummyphp_wq, &dslot->remove_work);

	pci_dev_put(dev);
	}
	return 0;
	}

	static void cleanup_slots (void)
	{
	struct list_head *tmp;
	struct list_head *next;
	struct dummy_slot *dslot;

	destroy_workqueue(dummyphp_wq);
	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");

	dummyphp_wq = create_singlethread_workqueue(MY_NAME);
	if (!dummyphp_wq)
	return -ENOMEM;

	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");
	module_param(dup_slots, bool, S_IRUGO \| S_IWUSR);
	MODULE_PARM_DESC(dup_slots, "Force duplicate slot names for debugging");