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/pci_hotplug.h>
  39 #include <linux/init.h>
  40 #include <linux/string.h>
  41 #include <linux/slab.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 ((dev = pci_get_slot(bus, temp->devfn)) != NULL)
 185                         pci_dev_put(dev);
 186                 else {
 187                         dev = pci_scan_single_device(bus, temp->devfn);
 188                         if (dev) {
 189                                 dbg("New device on %s function %x:%x\n",
 190                                         bus->name, temp->devfn >> 3,
 191                                         temp->devfn & 7);
 192                                 retval = pci_bus_add_device(dev);
 193                                 if (retval)
 194                                         dev_err(&dev->dev, "error adding "
 195                                                 "device, continuing.\n");
 196                                 else
 197                                         add_slot(dev);
 198                         }
 199                 }
 200                 /* multifunction device? */
 201                 if (!(hdr_type & 0x80))
 202                         return;
 203
 204                 /* continue scanning for other functions */
 205                 for (func = 1, temp->devfn++; func < 8; func++, temp->devfn++) {
 206                         if (pci_read_config_byte(temp, PCI_HEADER_TYPE, &hdr_type))
 207                                 continue;
 208                         temp->hdr_type = hdr_type & 0x7f;
 209
 210                         if ((dev = pci_get_slot(bus, temp->devfn)) != NULL)
 211                                 pci_dev_put(dev);
 212                         else {
 213                                 dev = pci_scan_single_device(bus, temp->devfn);
 214                                 if (dev) {
 215                                         dbg("New device on %s function %x:%x\n",
 216                                                 bus->name, temp->devfn >> 3,
 217                                                 temp->devfn & 7);
 218                                         retval = pci_bus_add_device(dev);
 219                                         if (retval)
 220                                                 dev_err(&dev->dev, "error adding "
 221                                                         "device, continuing.\n");
 222                                         else
 223                                                 add_slot(dev);
 224                                 }
 225                         }
 226                 }
 227         }
 228 }
 229
 230
 231 /**
 232  * Rescan PCI bus.
 233  * call pci_rescan_slot for each possible function of the bus
 234  *
 235  * @param bus
 236  */
 237 static void pci_rescan_bus(const struct pci_bus *bus)
 238 {
 239         unsigned int devfn;
 240         struct pci_dev *dev;
 241         dev = alloc_pci_dev();
 242         if (!dev)
 243                 return;
 244
 245         dev->bus = (struct pci_bus*)bus;
 246         dev->sysdata = bus->sysdata;
 247         for (devfn = 0; devfn < 0x100; devfn += 8) {
 248                 dev->devfn = devfn;
 249                 pci_rescan_slot(dev);
 250         }
 251         kfree(dev);
 252 }
 253
 254 /* recursively scan all buses */
 255 static void pci_rescan_buses(const struct list_head *list)
 256 {
 257         const struct list_head *l;
 258         list_for_each(l,list) {
 259                 const struct pci_bus *b = pci_bus_b(l);
 260                 pci_rescan_bus(b);
 261                 pci_rescan_buses(&b->children);
 262         }
 263 }
 264
 265 /* initiate rescan of all pci buses */
 266 static inline void pci_rescan(void) {
 267         pci_rescan_buses(&pci_root_buses);
 268 }
 269
 270
 271 static int enable_slot(struct hotplug_slot *hotplug_slot)
 272 {
 273         /* mis-use enable_slot for rescanning of the pci bus */
 274         pci_rescan();
 275         return -ENODEV;
 276 }
 277
 278 /* find the hotplug_slot for the pci_dev */
 279 static struct hotplug_slot *get_slot_from_dev(struct pci_dev *dev)
 280 {
 281         struct dummy_slot *dslot;
 282
 283         list_for_each_entry(dslot, &slot_list, node) {
 284                 if (dslot->dev == dev)
 285                         return dslot->slot;
 286         }
 287         return NULL;
 288 }
 289
 290
 291 static int disable_slot(struct hotplug_slot *slot)
 292 {
 293         struct dummy_slot *dslot;
 294         struct hotplug_slot *hslot;
 295         struct pci_dev *dev;
 296         int func;
 297
 298         if (!slot)
 299                 return -ENODEV;
 300         dslot = slot->private;
 301
 302         dbg("%s - physical_slot = %s\n", __FUNCTION__, slot->name);
 303
 304         /* don't disable bridged devices just yet, we can't handle them easily... */
 305         if (dslot->dev->subordinate) {
 306                 err("Can't remove PCI devices with other PCI devices behind it yet.\n");
 307                 return -ENODEV;
 308         }
 309         /* search for subfunctions and disable them first */
 310         if (!(dslot->dev->devfn & 7)) {
 311                 for (func = 1; func < 8; func++) {
 312                         dev = pci_get_slot(dslot->dev->bus,
 313                                         dslot->dev->devfn + func);
 314                         if (dev) {
 315                                 hslot = get_slot_from_dev(dev);
 316                                 if (hslot)
 317                                         disable_slot(hslot);
 318                                 else {
 319                                         err("Hotplug slot not found for subfunction of PCI device\n");
 320                                         return -ENODEV;
 321                                 }
 322                                 pci_dev_put(dev);
 323                         } else
 324                                 dbg("No device in slot found\n");
 325                 }
 326         }
 327
 328         /* remove the device from the pci core */
 329         pci_remove_bus_device(dslot->dev);
 330
 331         /* blow away this sysfs entry and other parts. */
 332         remove_slot(dslot);
 333
 334         return 0;
 335 }
 336
 337 static void cleanup_slots (void)
 338 {
 339         struct list_head *tmp;
 340         struct list_head *next;
 341         struct dummy_slot *dslot;
 342
 343         list_for_each_safe (tmp, next, &slot_list) {
 344                 dslot = list_entry (tmp, struct dummy_slot, node);
 345                 remove_slot(dslot);
 346         }
 347
 348 }
 349
 350 static int __init dummyphp_init(void)
 351 {
 352         info(DRIVER_DESC "\n");
 353
 354         return pci_scan_buses();
 355 }
 356
 357
 358 static void __exit dummyphp_exit(void)
 359 {
 360         cleanup_slots();
 361 }
 362
 363 module_init(dummyphp_init);
 364 module_exit(dummyphp_exit);
 365
 366 MODULE_AUTHOR(DRIVER_AUTHOR);
 367 MODULE_DESCRIPTION(DRIVER_DESC);
 368 MODULE_LICENSE("GPL");
 369 module_param(debug, bool, S_IRUGO | S_IWUSR);
 370 MODULE_PARM_DESC(debug, "Debugging mode enabled or not");
 371