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