drivers/pci/hotplug/fakephp.c

   1 /*
   2  * Fake PCI Hot Plug Controller Driver
   3  *
   4  * Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
   5  * Copyright (C) 2003 IBM Corp.
   6  * Copyright (C) 2003 Rolf Eike Beer <eike-kernel@sf-tec.de>
   7  *
   8  * Based on ideas and code from:
   9  *      Vladimir Kondratiev <vladimir.kondratiev@intel.com>
  10  *      Rolf Eike Beer <eike-kernel@sf-tec.de>
  11  *
  12  * All rights reserved.
  13  *
  14  * This program is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation, version 2 of the License.
  17  *
  18  * Send feedback to <greg@kroah.com>
  19  */
  20
  21 /*
  22  *
  23  * This driver will "emulate" removing PCI devices from the system.  If
  24  * the "power" file is written to with "0" then the specified PCI device
  25  * will be completely removed from the kernel.
  26  *
  27  * WARNING, this does NOT turn off the power to the PCI device.  This is
  28  * a "logical" removal, not a physical or electrical removal.
  29  *
  30  * Use this module at your own risk, you have been warned!
  31  *
  32  * Enabling PCI devices is left as an exercise for the reader...
  33  *
  34  */
  35 #include <linux/kernel.h>
  36 #include <linux/module.h>
  37 #include <linux/pci.h>
  38 #include <linux/init.h>
  39 #include <linux/string.h>
  40 #include <linux/slab.h>
  41 #include "pci_hotplug.h"
  42 #include "../pci.h"
  43
  44 #if !defined(MODULE)
  45         #define MY_NAME "fakephp"
  46 #else
  47         #define MY_NAME THIS_MODULE->name
  48 #endif
  49
  50 #define dbg(format, arg...)                                     \
  51         do {                                                    \
  52                 if (debug)                                      \
  53                         printk(KERN_DEBUG "%s: " format,        \
  54                                 MY_NAME , ## arg);              \
  55         } while (0)
  56 #define err(format, arg...) printk(KERN_ERR "%s: " format, MY_NAME , ## arg)
  57 #define info(format, arg...) printk(KERN_INFO "%s: " format, MY_NAME , ## arg)
  58
  59 #define DRIVER_AUTHOR   "Greg Kroah-Hartman <greg@kroah.com>"
  60 #define DRIVER_DESC     "Fake PCI Hot Plug Controller Driver"
  61
  62 struct dummy_slot {
  63         struct list_head node;
  64         struct hotplug_slot *slot;
  65         struct pci_dev *dev;
  66 };
  67
  68 static int debug;
  69 static LIST_HEAD(slot_list);
  70
  71 static int enable_slot (struct hotplug_slot *slot);
  72 static int disable_slot (struct hotplug_slot *slot);
  73
  74 static struct hotplug_slot_ops dummy_hotplug_slot_ops = {
  75         .owner                  = THIS_MODULE,
  76         .enable_slot            = enable_slot,
  77         .disable_slot           = disable_slot,
  78 };
  79
  80 static void dummy_release(struct hotplug_slot *slot)
  81 {
  82         struct dummy_slot *dslot = slot->private;
  83
  84         list_del(&dslot->node);
  85         kfree(dslot->slot->info);
  86         kfree(dslot->slot);
  87         pci_dev_put(dslot->dev);
  88         kfree(dslot);
  89 }
  90
  91 static int add_slot(struct pci_dev *dev)
  92 {
  93         struct dummy_slot *dslot;
  94         struct hotplug_slot *slot;
  95         int retval = -ENOMEM;
  96
  97         slot = kzalloc(sizeof(struct hotplug_slot), GFP_KERNEL);
  98         if (!slot)
  99                 goto error;
 100
 101         slot->info = kzalloc(sizeof(struct hotplug_slot_info), GFP_KERNEL);
 102         if (!slot->info)
 103                 goto error_slot;
 104
 105         slot->info->power_status = 1;
 106         slot->info->max_bus_speed = PCI_SPEED_UNKNOWN;
 107         slot->info->cur_bus_speed = PCI_SPEED_UNKNOWN;
 108
 109         slot->name = &dev->dev.bus_id[0];
 110         dbg("slot->name = %s\n", slot->name);
 111
 112         dslot = kmalloc(sizeof(struct dummy_slot), GFP_KERNEL);
 113         if (!dslot)
 114                 goto error_info;
 115
 116         slot->ops = &dummy_hotplug_slot_ops;
 117         slot->release = &dummy_release;
 118         slot->private = dslot;
 119
 120         retval = pci_hp_register(slot);
 121         if (retval) {
 122                 err("pci_hp_register failed with error %d\n", retval);
 123                 goto error_dslot;
 124         }
 125
 126         dslot->slot = slot;
 127         dslot->dev = pci_dev_get(dev);
 128         list_add (&dslot->node, &slot_list);
 129         return retval;
 130
 131 error_dslot:
 132         kfree(dslot);
 133 error_info:
 134         kfree(slot->info);
 135 error_slot:
 136         kfree(slot);
 137 error:
 138         return retval;
 139 }
 140
 141 static int __init pci_scan_buses(void)
 142 {
 143         struct pci_dev *dev = NULL;
 144         int retval = 0;
 145
 146         while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
 147                 retval = add_slot(dev);
 148                 if (retval) {
 149                         pci_dev_put(dev);
 150                         break;
 151                 }
 152         }
 153
 154         return retval;
 155 }
 156
 157 static void remove_slot(struct dummy_slot *dslot)
 158 {
 159         int retval;
 160
 161         dbg("removing slot %s\n", dslot->slot->name);
 162         retval = pci_hp_deregister(dslot->slot);
 163         if (retval)
 164                 err("Problem unregistering a slot %s\n", dslot->slot->name);
 165 }
 166
 167 /**
 168  * Rescan slot.
 169  * Tries hard not to re-enable already existing devices
 170  * also handles scanning of subfunctions
 171  *
 172  * @param temp   Device template. Should be set: bus and devfn.
 173  */
 174 static void pci_rescan_slot(struct pci_dev *temp)
 175 {
 176         struct pci_bus *bus = temp->bus;
 177         struct pci_dev *dev;
 178         int func;
 179         int retval;
 180         u8 hdr_type;
 181
 182         if (!pci_read_config_byte(temp, PCI_HEADER_TYPE, &hdr_type)) {
 183                 temp->hdr_type = hdr_type & 0x7f;
 184                 if (!pci_find_slot(bus->number, temp->devfn)) {
 185                         dev = pci_scan_single_device(bus, temp->devfn);
 186                         if (dev) {
 187                                 dbg("New device on %s function %x:%x\n",
 188                                         bus->name, temp->devfn >> 3,
 189                                         temp->devfn & 7);
 190                                 retval = pci_bus_add_device(dev);
 191                                 if (retval)
 192                                         dev_err(&dev->dev, "error adding "
 193                                                 "device, continuing.\n");
 194                                 else
 195                                         add_slot(dev);
 196                         }
 197                 }
 198                 /* multifunction device? */
 199                 if (!(hdr_type & 0x80))
 200                         return;
 201
 202                 /* continue scanning for other functions */
 203                 for (func = 1, temp->devfn++; func < 8; func++, temp->devfn++) {
 204                         if (pci_read_config_byte(temp, PCI_HEADER_TYPE, &hdr_type))
 205                                 continue;
 206                         temp->hdr_type = hdr_type & 0x7f;
 207
 208                         if (!pci_find_slot(bus->number, temp->devfn)) {
 209                                 dev = pci_scan_single_device(bus, temp->devfn);
 210                                 if (dev) {
 211                                         dbg("New device on %s function %x:%x\n",
 212                                                 bus->name, temp->devfn >> 3,
 213                                                 temp->devfn & 7);
 214                                         retval = pci_bus_add_device(dev);
 215                                         if (retval)
 216                                                 dev_err(&dev->dev, "error adding "
 217                                                         "device, continuing.\n");
 218                                         else
 219                                                 add_slot(dev);
 220                                 }
 221                         }
 222                 }
 223         }
 224 }
 225
 226
 227 /**
 228  * Rescan PCI bus.
 229  * call pci_rescan_slot for each possible function of the bus
 230  *
 231  * @param bus
 232  */
 233 static void pci_rescan_bus(const struct pci_bus *bus)
 234 {
 235         unsigned int devfn;
 236         struct pci_dev *dev;
 237         dev = kzalloc(sizeof(struct pci_dev), GFP_KERNEL);
 238         if (!dev)
 239                 return;
 240
 241         dev->bus = (struct pci_bus*)bus;
 242         dev->sysdata = bus->sysdata;
 243         for (devfn = 0; devfn < 0x100; devfn += 8) {
 244                 dev->devfn = devfn;
 245                 pci_rescan_slot(dev);
 246         }
 247         kfree(dev);
 248 }
 249
 250 /* recursively scan all buses */
 251 static void pci_rescan_buses(const struct list_head *list)
 252 {
 253         const struct list_head *l;
 254         list_for_each(l,list) {
 255                 const struct pci_bus *b = pci_bus_b(l);
 256                 pci_rescan_bus(b);
 257                 pci_rescan_buses(&b->children);
 258         }
 259 }
 260
 261 /* initiate rescan of all pci buses */
 262 static inline void pci_rescan(void) {
 263         pci_rescan_buses(&pci_root_buses);
 264 }
 265
 266
 267 static int enable_slot(struct hotplug_slot *hotplug_slot)
 268 {
 269         /* mis-use enable_slot for rescanning of the pci bus */
 270         pci_rescan();
 271         return -ENODEV;
 272 }
 273
 274 /* find the hotplug_slot for the pci_dev */
 275 static struct hotplug_slot *get_slot_from_dev(struct pci_dev *dev)
 276 {
 277         struct dummy_slot *dslot;
 278
 279         list_for_each_entry(dslot, &slot_list, node) {
 280                 if (dslot->dev == dev)
 281                         return dslot->slot;
 282         }
 283         return NULL;
 284 }
 285
 286
 287 static int disable_slot(struct hotplug_slot *slot)
 288 {
 289         struct dummy_slot *dslot;
 290         struct hotplug_slot *hslot;
 291         struct pci_dev *dev;
 292         int func;
 293
 294         if (!slot)
 295                 return -ENODEV;
 296         dslot = slot->private;
 297
 298         dbg("%s - physical_slot = %s\n", __FUNCTION__, slot->name);
 299
 300         /* don't disable bridged devices just yet, we can't handle them easily... */
 301         if (dslot->dev->subordinate) {
 302                 err("Can't remove PCI devices with other PCI devices behind it yet.\n");
 303                 return -ENODEV;
 304         }
 305         /* search for subfunctions and disable them first */
 306         if (!(dslot->dev->devfn & 7)) {
 307                 for (func = 1; func < 8; func++) {
 308                         dev = pci_find_slot(dslot->dev->bus->number,
 309                                         dslot->dev->devfn + func);
 310                         if (dev) {
 311                                 hslot = get_slot_from_dev(dev);
 312                                 if (hslot)
 313                                         disable_slot(hslot);
 314                                 else {
 315                                         err("Hotplug slot not found for subfunction of PCI device\n");
 316                                         return -ENODEV;
 317                                 }
 318                         } else
 319                                 dbg("No device in slot found\n");
 320                 }
 321         }
 322
 323         /* remove the device from the pci core */
 324         pci_remove_bus_device(dslot->dev);
 325
 326         /* blow away this sysfs entry and other parts. */
 327         remove_slot(dslot);
 328
 329         return 0;
 330 }
 331
 332 static void cleanup_slots (void)
 333 {
 334         struct list_head *tmp;
 335         struct list_head *next;
 336         struct dummy_slot *dslot;
 337
 338         list_for_each_safe (tmp, next, &slot_list) {
 339                 dslot = list_entry (tmp, struct dummy_slot, node);
 340                 remove_slot(dslot);
 341         }
 342
 343 }
 344
 345 static int __init dummyphp_init(void)
 346 {
 347         info(DRIVER_DESC "\n");
 348
 349         return pci_scan_buses();
 350 }
 351
 352
 353 static void __exit dummyphp_exit(void)
 354 {
 355         cleanup_slots();
 356 }
 357
 358 module_init(dummyphp_init);
 359 module_exit(dummyphp_exit);
 360
 361 MODULE_AUTHOR(DRIVER_AUTHOR);
 362 MODULE_DESCRIPTION(DRIVER_DESC);
 363 MODULE_LICENSE("GPL");
 364 module_param(debug, bool, S_IRUGO | S_IWUSR);
 365 MODULE_PARM_DESC(debug, "Debugging mode enabled or not");
 366