/*
* 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 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);
}
static int add_slot(struct pci_dev *dev)
{
struct dummy_slot *dslot;
struct hotplug_slot *slot;
int retval = -ENOMEM;
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;
slot->name = &dev->dev.bus_id[0];
dbg("slot->name = %s\n", slot->name);
dslot = kzalloc(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);
}
/* 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 void pci_rescan_slot(struct pci_dev *temp)
{
struct pci_bus *bus = temp->bus;
struct pci_dev *dev;
int func;
int retval;
u8 hdr_type;
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);
retval = pci_bus_add_device(dev);
if (retval)
dev_err(&dev->dev, "error adding "
"device, continuing.\n");
else
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 ((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);
retval = pci_bus_add_device(dev);
if (retval)
dev_err(&dev->dev, "error adding "
"device, continuing.\n");
else
add_slot(dev);
}
}
}
}
}
/**
* 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;
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;
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);
}
/* 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;
}
/* 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", __func__, 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;
}
if (test_and_set_bit(0, &dslot->removed)) {
dbg("Slot already scheduled for removal\n");
return -ENODEV;
}
/* search for subfunctions and disable them first */
if (!(dslot->dev->devfn & 7)) {
for (func = 1; func < 8; func++) {
dev = pci_get_slot(dslot->dev->bus,
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;
}
pci_dev_put(dev);
} else
dbg("No device in slot found\n");
}
}
/* remove the device from the pci core */
pci_remove_bus_device(dslot->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);
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");
