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