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/*

 * 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 "../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 = 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 = 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);

}

/**

 * 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);

}

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_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);

        /* 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");