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 "pci_hotplug.h"
  41 #include "../pci.h"
  42
  43 #if !defined(MODULE)
  44         #define MY_NAME "fakephp"
  45 #else
  46         #define MY_NAME THIS_MODULE->name
  47 #endif
  48
  49 #define dbg(format, arg...)                                     \
  50         do {                                                    \
  51                 if (debug)                                      \
  52                         printk(KERN_DEBUG "%s: " format,        \
  53                                 MY_NAME , ## arg);              \
  54         } while (0)
  55 #define err(format, arg...) printk(KERN_ERR "%s: " format, MY_NAME , ## arg)
  56 #define info(format, arg...) printk(KERN_INFO "%s: " format, MY_NAME , ## arg)
  57
  58 #define DRIVER_AUTHOR   "Greg Kroah-Hartman <greg@kroah.com>"
  59 #define DRIVER_DESC     "Fake PCI Hot Plug Controller Driver"
  60
  61 struct dummy_slot {
  62         struct list_head node;
  63         struct hotplug_slot *slot;
  64         struct pci_dev *dev;
  65 };
  66
  67 static int debug;
  68 static LIST_HEAD(slot_list);
  69
  70 static int enable_slot (struct hotplug_slot *slot);
  71 static int disable_slot (struct hotplug_slot *slot);
  72
  73 static struct hotplug_slot_ops dummy_hotplug_slot_ops = {
  74         .owner                  = THIS_MODULE,
  75         .enable_slot            = enable_slot,
  76         .disable_slot           = disable_slot,
  77 };
  78
  79 static void dummy_release(struct hotplug_slot *slot)
  80 {
  81         struct dummy_slot *dslot = slot->private;
  82
  83         list_del(&dslot->node);
  84         kfree(dslot->slot->info);
  85         kfree(dslot->slot);
  86         pci_dev_put(dslot->dev);
  87         kfree(dslot);
  88 }
  89
  90 static int add_slot(struct pci_dev *dev)
  91 {
  92         struct dummy_slot *dslot;
  93         struct hotplug_slot *slot;
  94         int retval = -ENOMEM;
  95
  96         slot = kmalloc(sizeof(struct hotplug_slot), GFP_KERNEL);
  97         if (!slot)
  98                 goto error;
  99         memset(slot, 0, sizeof(*slot));
 100
 101         slot->info = kmalloc(sizeof(struct hotplug_slot_info), GFP_KERNEL);
 102         if (!slot->info)
 103                 goto error_slot;
 104         memset(slot->info, 0, sizeof(struct hotplug_slot_info));
 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 = kmalloc(sizeof(struct pci_dev), GFP_KERNEL);
 229         if (!dev)
 230                 return;
 231
 232         memset(dev, 0, sizeof(dev));
 233         dev->bus = (struct pci_bus*)bus;
 234         dev->sysdata = bus->sysdata;
 235         for (devfn = 0; devfn < 0x100; devfn += 8) {
 236                 dev->devfn = devfn;
 237                 pci_rescan_slot(dev);
 238         }
 239         kfree(dev);
 240 }
 241
 242 /* recursively scan all buses */
 243 static void pci_rescan_buses(const struct list_head *list)
 244 {
 245         const struct list_head *l;
 246         list_for_each(l,list) {
 247                 const struct pci_bus *b = pci_bus_b(l);
 248                 pci_rescan_bus(b);
 249                 pci_rescan_buses(&b->children);
 250         }
 251 }
 252
 253 /* initiate rescan of all pci buses */
 254 static inline void pci_rescan(void) {
 255         pci_rescan_buses(&pci_root_buses);
 256 }
 257
 258
 259 static int enable_slot(struct hotplug_slot *hotplug_slot)
 260 {
 261         /* mis-use enable_slot for rescanning of the pci bus */
 262         pci_rescan();
 263         return -ENODEV;
 264 }
 265
 266 /* find the hotplug_slot for the pci_dev */
 267 static struct hotplug_slot *get_slot_from_dev(struct pci_dev *dev)
 268 {
 269         struct dummy_slot *dslot;
 270
 271         list_for_each_entry(dslot, &slot_list, node) {
 272                 if (dslot->dev == dev)
 273                         return dslot->slot;
 274         }
 275         return NULL;
 276 }
 277
 278
 279 static int disable_slot(struct hotplug_slot *slot)
 280 {
 281         struct dummy_slot *dslot;
 282         struct hotplug_slot *hslot;
 283         struct pci_dev *dev;
 284         int func;
 285
 286         if (!slot)
 287                 return -ENODEV;
 288         dslot = slot->private;
 289
 290         dbg("%s - physical_slot = %s\n", __FUNCTION__, slot->name);
 291
 292         /* don't disable bridged devices just yet, we can't handle them easily... */
 293         if (dslot->dev->subordinate) {
 294                 err("Can't remove PCI devices with other PCI devices behind it yet.\n");
 295                 return -ENODEV;
 296         }
 297         /* search for subfunctions and disable them first */
 298         if (!(dslot->dev->devfn & 7)) {
 299                 for (func = 1; func < 8; func++) {
 300                         dev = pci_find_slot(dslot->dev->bus->number,
 301                                         dslot->dev->devfn + func);
 302                         if (dev) {
 303                                 hslot = get_slot_from_dev(dev);
 304                                 if (hslot)
 305                                         disable_slot(hslot);
 306                                 else {
 307                                         err("Hotplug slot not found for subfunction of PCI device\n");
 308                                         return -ENODEV;
 309                                 }
 310                         } else
 311                                 dbg("No device in slot found\n");
 312                 }
 313         }
 314
 315         /* remove the device from the pci core */
 316         pci_remove_bus_device(dslot->dev);
 317
 318         /* blow away this sysfs entry and other parts. */
 319         remove_slot(dslot);
 320
 321         return 0;
 322 }
 323
 324 static void cleanup_slots (void)
 325 {
 326         struct list_head *tmp;
 327         struct list_head *next;
 328         struct dummy_slot *dslot;
 329
 330         list_for_each_safe (tmp, next, &slot_list) {
 331                 dslot = list_entry (tmp, struct dummy_slot, node);
 332                 remove_slot(dslot);
 333         }
 334
 335 }
 336
 337 static int __init dummyphp_init(void)
 338 {
 339         info(DRIVER_DESC "\n");
 340
 341         return pci_scan_buses();
 342 }
 343
 344
 345 static void __exit dummyphp_exit(void)
 346 {
 347         cleanup_slots();
 348 }
 349
 350 module_init(dummyphp_init);
 351 module_exit(dummyphp_exit);
 352
 353 MODULE_AUTHOR(DRIVER_AUTHOR);
 354 MODULE_DESCRIPTION(DRIVER_DESC);
 355 MODULE_LICENSE("GPL");
 356 module_param(debug, bool, S_IRUGO | S_IWUSR);
 357 MODULE_PARM_DESC(debug, "Debugging mode enabled or not");
 358