drivers/pci/hotplug/sgi_hotplug.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 2005-2006 Silicon Graphics, Inc. All rights reserved.
   7  *
   8  * This work was based on the 2.4/2.6 kernel development by Dick Reigner.
   9  * Work to add BIOS PROM support was completed by Mike Habeck.
  10  */
  11
  12 #include <linux/init.h>
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/pci.h>
  16 #include <linux/pci_hotplug.h>
  17 #include <linux/proc_fs.h>
  18 #include <linux/types.h>
  19 #include <linux/mutex.h>
  20
  21 #include <asm/sn/addrs.h>
  22 #include <asm/sn/geo.h>
  23 #include <asm/sn/l1.h>
  24 #include <asm/sn/module.h>
  25 #include <asm/sn/pcibr_provider.h>
  26 #include <asm/sn/pcibus_provider_defs.h>
  27 #include <asm/sn/pcidev.h>
  28 #include <asm/sn/sn_feature_sets.h>
  29 #include <asm/sn/sn_sal.h>
  30 #include <asm/sn/types.h>
  31 #include <linux/acpi.h>
  32 #include <asm/sn/acpi.h>
  33
  34 #include "../pci.h"
  35
  36 MODULE_LICENSE("GPL");
  37 MODULE_AUTHOR("SGI (prarit@sgi.com, dickie@sgi.com, habeck@sgi.com)");
  38 MODULE_DESCRIPTION("SGI Altix Hot Plug PCI Controller Driver");
  39
  40
  41 /* SAL call error codes. Keep in sync with prom header io/include/pcibr.h */
  42 #define PCI_SLOT_ALREADY_UP             2       /* slot already up */
  43 #define PCI_SLOT_ALREADY_DOWN           3       /* slot already down */
  44 #define PCI_L1_ERR                      7       /* L1 console command error */
  45 #define PCI_EMPTY_33MHZ                 15      /* empty 33 MHz bus */
  46
  47
  48 #define PCIIO_ASIC_TYPE_TIOCA           4
  49 #define PCI_L1_QSIZE                    128     /* our L1 message buffer size */
  50 #define SN_MAX_HP_SLOTS                 32      /* max hotplug slots */
  51 #define SN_SLOT_NAME_SIZE               33      /* size of name string */
  52
  53 /* internal list head */
  54 static struct list_head sn_hp_list;
  55
  56 /* hotplug_slot struct's private pointer */
  57 struct slot {
  58         int device_num;
  59         struct pci_bus *pci_bus;
  60         /* this struct for glue internal only */
  61         struct hotplug_slot *hotplug_slot;
  62         struct list_head hp_list;
  63         char physical_path[SN_SLOT_NAME_SIZE];
  64 };
  65
  66 struct pcibr_slot_enable_resp {
  67         int resp_sub_errno;
  68         char resp_l1_msg[PCI_L1_QSIZE + 1];
  69 };
  70
  71 struct pcibr_slot_disable_resp {
  72         int resp_sub_errno;
  73         char resp_l1_msg[PCI_L1_QSIZE + 1];
  74 };
  75
  76 enum sn_pci_req_e {
  77         PCI_REQ_SLOT_ELIGIBLE,
  78         PCI_REQ_SLOT_DISABLE
  79 };
  80
  81 static int enable_slot(struct hotplug_slot *slot);
  82 static int disable_slot(struct hotplug_slot *slot);
  83 static inline int get_power_status(struct hotplug_slot *slot, u8 *value);
  84
  85 static struct hotplug_slot_ops sn_hotplug_slot_ops = {
  86         .enable_slot            = enable_slot,
  87         .disable_slot           = disable_slot,
  88         .get_power_status       = get_power_status,
  89 };
  90
  91 static DEFINE_MUTEX(sn_hotplug_mutex);
  92
  93 static ssize_t path_show(struct pci_slot *pci_slot, char *buf)
  94 {
  95         int retval = -ENOENT;
  96         struct slot *slot = pci_slot->hotplug->private;
  97
  98         if (!slot)
  99                 return retval;
 100
 101         retval = sprintf (buf, "%s\n", slot->physical_path);
 102         return retval;
 103 }
 104
 105 static struct pci_slot_attribute sn_slot_path_attr = __ATTR_RO(path);
 106
 107 static int sn_pci_slot_valid(struct pci_bus *pci_bus, int device)
 108 {
 109         struct pcibus_info *pcibus_info;
 110         u16 busnum, segment, ioboard_type;
 111
 112         pcibus_info = SN_PCIBUS_BUSSOFT_INFO(pci_bus);
 113
 114         /* Check to see if this is a valid slot on 'pci_bus' */
 115         if (!(pcibus_info->pbi_valid_devices & (1 << device)))
 116                 return -EPERM;
 117
 118         ioboard_type = sn_ioboard_to_pci_bus(pci_bus);
 119         busnum = pcibus_info->pbi_buscommon.bs_persist_busnum;
 120         segment = pci_domain_nr(pci_bus) & 0xf;
 121
 122         /* Do not allow hotplug operations on base I/O cards */
 123         if ((ioboard_type == L1_BRICKTYPE_IX ||
 124              ioboard_type == L1_BRICKTYPE_IA) &&
 125             (segment == 1 && busnum == 0 && device != 1))
 126                 return -EPERM;
 127
 128         return 1;
 129 }
 130
 131 static int sn_pci_bus_valid(struct pci_bus *pci_bus)
 132 {
 133         struct pcibus_info *pcibus_info;
 134         u32 asic_type;
 135         u16 ioboard_type;
 136
 137         /* Don't register slots hanging off the TIOCA bus */
 138         pcibus_info = SN_PCIBUS_BUSSOFT_INFO(pci_bus);
 139         asic_type = pcibus_info->pbi_buscommon.bs_asic_type;
 140         if (asic_type == PCIIO_ASIC_TYPE_TIOCA)
 141                 return -EPERM;
 142
 143         /* Only register slots in I/O Bricks that support hotplug */
 144         ioboard_type = sn_ioboard_to_pci_bus(pci_bus);
 145         switch (ioboard_type) {
 146                 case L1_BRICKTYPE_IX:
 147                 case L1_BRICKTYPE_PX:
 148                 case L1_BRICKTYPE_IA:
 149                 case L1_BRICKTYPE_PA:
 150                 case L1_BOARDTYPE_PCIX3SLOT:
 151                         return 1;
 152                         break;
 153                 default:
 154                         return -EPERM;
 155                         break;
 156         }
 157
 158         return -EIO;
 159 }
 160
 161 static int sn_hp_slot_private_alloc(struct hotplug_slot *bss_hotplug_slot,
 162                                     struct pci_bus *pci_bus, int device,
 163                                     char *name)
 164 {
 165         struct pcibus_info *pcibus_info;
 166         struct slot *slot;
 167
 168         pcibus_info = SN_PCIBUS_BUSSOFT_INFO(pci_bus);
 169
 170         slot = kzalloc(sizeof(*slot), GFP_KERNEL);
 171         if (!slot)
 172                 return -ENOMEM;
 173         bss_hotplug_slot->private = slot;
 174
 175         slot->device_num = device;
 176         slot->pci_bus = pci_bus;
 177         sprintf(name, "%04x:%02x:%02x",
 178                 pci_domain_nr(pci_bus),
 179                 ((u16)pcibus_info->pbi_buscommon.bs_persist_busnum),
 180                 device + 1);
 181
 182         sn_generate_path(pci_bus, slot->physical_path);
 183
 184         slot->hotplug_slot = bss_hotplug_slot;
 185         list_add(&slot->hp_list, &sn_hp_list);
 186
 187         return 0;
 188 }
 189
 190 static struct hotplug_slot * sn_hp_destroy(void)
 191 {
 192         struct slot *slot;
 193         struct pci_slot *pci_slot;
 194         struct hotplug_slot *bss_hotplug_slot = NULL;
 195
 196         list_for_each_entry(slot, &sn_hp_list, hp_list) {
 197                 bss_hotplug_slot = slot->hotplug_slot;
 198                 pci_slot = bss_hotplug_slot->pci_slot;
 199                 list_del(&((struct slot *)bss_hotplug_slot->private)->
 200                          hp_list);
 201                 sysfs_remove_file(&pci_slot->kobj,
 202                                   &sn_slot_path_attr.attr);
 203                 break;
 204         }
 205         return bss_hotplug_slot;
 206 }
 207
 208 static void sn_bus_free_data(struct pci_dev *dev)
 209 {
 210         struct pci_bus *subordinate_bus;
 211         struct pci_dev *child;
 212
 213         /* Recursively clean up sn_irq_info structs */
 214         if (dev->subordinate) {
 215                 subordinate_bus = dev->subordinate;
 216                 list_for_each_entry(child, &subordinate_bus->devices, bus_list)
 217                         sn_bus_free_data(child);
 218         }
 219         /*
 220          * Some drivers may use dma accesses during the
 221          * driver remove function. We release the sysdata
 222          * areas after the driver remove functions have
 223          * been called.
 224          */
 225         sn_bus_store_sysdata(dev);
 226         sn_pci_unfixup_slot(dev);
 227 }
 228
 229 static int sn_slot_enable(struct hotplug_slot *bss_hotplug_slot,
 230                           int device_num, char **ssdt)
 231 {
 232         struct slot *slot = bss_hotplug_slot->private;
 233         struct pcibus_info *pcibus_info;
 234         struct pcibr_slot_enable_resp resp;
 235         int rc;
 236
 237         pcibus_info = SN_PCIBUS_BUSSOFT_INFO(slot->pci_bus);
 238
 239         /*
 240          * Power-on and initialize the slot in the SN
 241          * PCI infrastructure.
 242          */
 243         rc = sal_pcibr_slot_enable(pcibus_info, device_num, &resp, ssdt);
 244
 245
 246         if (rc == PCI_SLOT_ALREADY_UP) {
 247                 dev_dbg(&slot->pci_bus->self->dev, "is already active\n");
 248                 return 1; /* return 1 to user */
 249         }
 250
 251         if (rc == PCI_L1_ERR) {
 252                 dev_dbg(&slot->pci_bus->self->dev,
 253                         "L1 failure %d with message: %s",
 254                         resp.resp_sub_errno, resp.resp_l1_msg);
 255                 return -EPERM;
 256         }
 257
 258         if (rc) {
 259                 dev_dbg(&slot->pci_bus->self->dev,
 260                         "insert failed with error %d sub-error %d\n",
 261                         rc, resp.resp_sub_errno);
 262                 return -EIO;
 263         }
 264
 265         pcibus_info = SN_PCIBUS_BUSSOFT_INFO(slot->pci_bus);
 266         pcibus_info->pbi_enabled_devices |= (1 << device_num);
 267
 268         return 0;
 269 }
 270
 271 static int sn_slot_disable(struct hotplug_slot *bss_hotplug_slot,
 272                            int device_num, int action)
 273 {
 274         struct slot *slot = bss_hotplug_slot->private;
 275         struct pcibus_info *pcibus_info;
 276         struct pcibr_slot_disable_resp resp;
 277         int rc;
 278
 279         pcibus_info = SN_PCIBUS_BUSSOFT_INFO(slot->pci_bus);
 280
 281         rc = sal_pcibr_slot_disable(pcibus_info, device_num, action, &resp);
 282
 283         if ((action == PCI_REQ_SLOT_ELIGIBLE) &&
 284             (rc == PCI_SLOT_ALREADY_DOWN)) {
 285                 dev_dbg(&slot->pci_bus->self->dev, "Slot %s already inactive\n", slot->physical_path);
 286                 return 1; /* return 1 to user */
 287         }
 288
 289         if ((action == PCI_REQ_SLOT_ELIGIBLE) && (rc == PCI_EMPTY_33MHZ)) {
 290                 dev_dbg(&slot->pci_bus->self->dev,
 291                         "Cannot remove last 33MHz card\n");
 292                 return -EPERM;
 293         }
 294
 295         if ((action == PCI_REQ_SLOT_ELIGIBLE) && (rc == PCI_L1_ERR)) {
 296                 dev_dbg(&slot->pci_bus->self->dev,
 297                         "L1 failure %d with message \n%s\n",
 298                         resp.resp_sub_errno, resp.resp_l1_msg);
 299                 return -EPERM;
 300         }
 301
 302         if ((action == PCI_REQ_SLOT_ELIGIBLE) && rc) {
 303                 dev_dbg(&slot->pci_bus->self->dev,
 304                         "remove failed with error %d sub-error %d\n",
 305                         rc, resp.resp_sub_errno);
 306                 return -EIO;
 307         }
 308
 309         if ((action == PCI_REQ_SLOT_ELIGIBLE) && !rc)
 310                 return 0;
 311
 312         if ((action == PCI_REQ_SLOT_DISABLE) && !rc) {
 313                 pcibus_info = SN_PCIBUS_BUSSOFT_INFO(slot->pci_bus);
 314                 pcibus_info->pbi_enabled_devices &= ~(1 << device_num);
 315                 dev_dbg(&slot->pci_bus->self->dev, "remove successful\n");
 316                 return 0;
 317         }
 318
 319         if ((action == PCI_REQ_SLOT_DISABLE) && rc) {
 320                 dev_dbg(&slot->pci_bus->self->dev,"remove failed rc = %d\n", rc);
 321         }
 322
 323         return rc;
 324 }
 325
 326 /*
 327  * Power up and configure the slot via a SAL call to PROM.
 328  * Scan slot (and any children), do any platform specific fixup,
 329  * and find device driver.
 330  */
 331 static int enable_slot(struct hotplug_slot *bss_hotplug_slot)
 332 {
 333         struct slot *slot = bss_hotplug_slot->private;
 334         struct pci_bus *new_bus = NULL;
 335         struct pci_dev *dev;
 336         int func, num_funcs;
 337         int new_ppb = 0;
 338         int rc;
 339         char *ssdt = NULL;
 340         void pcibios_fixup_device_resources(struct pci_dev *);
 341
 342         /* Serialize the Linux PCI infrastructure */
 343         mutex_lock(&sn_hotplug_mutex);
 344
 345         /*
 346          * Power-on and initialize the slot in the SN
 347          * PCI infrastructure. Also, retrieve the ACPI SSDT
 348          * table for the slot (if ACPI capable PROM).
 349          */
 350         rc = sn_slot_enable(bss_hotplug_slot, slot->device_num, &ssdt);
 351         if (rc) {
 352                 mutex_unlock(&sn_hotplug_mutex);
 353                 return rc;
 354         }
 355
 356         if (ssdt)
 357                 ssdt = __va(ssdt);
 358         /* Add the new SSDT for the slot to the ACPI namespace */
 359         if (SN_ACPI_BASE_SUPPORT() && ssdt) {
 360                 acpi_status ret;
 361
 362                 ret = acpi_load_table((struct acpi_table_header *)ssdt);
 363                 if (ACPI_FAILURE(ret)) {
 364                         printk(KERN_ERR "%s: acpi_load_table failed (0x%x)\n",
 365                                __func__, ret);
 366                         /* try to continue on */
 367                 }
 368         }
 369
 370         num_funcs = pci_scan_slot(slot->pci_bus,
 371                                   PCI_DEVFN(slot->device_num + 1, 0));
 372         if (!num_funcs) {
 373                 dev_dbg(&slot->pci_bus->self->dev, "no device in slot\n");
 374                 mutex_unlock(&sn_hotplug_mutex);
 375                 return -ENODEV;
 376         }
 377
 378         /*
 379          * Map SN resources for all functions on the card
 380          * to the Linux PCI interface and tell the drivers
 381          * about them.
 382          */
 383         for (func = 0; func < num_funcs;  func++) {
 384                 dev = pci_get_slot(slot->pci_bus,
 385                                    PCI_DEVFN(slot->device_num + 1,
 386                                              PCI_FUNC(func)));
 387                 if (dev) {
 388                         /* Need to do slot fixup on PPB before fixup of children
 389                          * (PPB's pcidev_info needs to be in pcidev_info list
 390                          * before child's SN_PCIDEV_INFO() call to setup
 391                          * pdi_host_pcidev_info).
 392                          */
 393                         pcibios_fixup_device_resources(dev);
 394                         if (SN_ACPI_BASE_SUPPORT())
 395                                 sn_acpi_slot_fixup(dev);
 396                         else
 397                                 sn_io_slot_fixup(dev);
 398                         if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
 399                                 unsigned char sec_bus;
 400                                 pci_read_config_byte(dev, PCI_SECONDARY_BUS,
 401                                                      &sec_bus);
 402                                 new_bus = pci_add_new_bus(dev->bus, dev,
 403                                                           sec_bus);
 404                                 pci_scan_child_bus(new_bus);
 405                                 new_ppb = 1;
 406                         }
 407                         pci_dev_put(dev);
 408                 }
 409         }
 410
 411         /*
 412          * Add the slot's devices to the ACPI infrastructure */
 413         if (SN_ACPI_BASE_SUPPORT() && ssdt) {
 414                 unsigned long long adr;
 415                 struct acpi_device *pdevice;
 416                 struct acpi_device *device;
 417                 acpi_handle phandle;
 418                 acpi_handle chandle = NULL;
 419                 acpi_handle rethandle;
 420                 acpi_status ret;
 421
 422                 phandle = PCI_CONTROLLER(slot->pci_bus)->acpi_handle;
 423
 424                 if (acpi_bus_get_device(phandle, &pdevice)) {
 425                         dev_dbg(&slot->pci_bus->self->dev,
 426                                 "no parent device, assuming NULL\n");
 427                         pdevice = NULL;
 428                 }
 429
 430                 /*
 431                  * Walk the rootbus node's immediate children looking for
 432                  * the slot's device node(s). There can be more than
 433                  * one for multifunction devices.
 434                  */
 435                 for (;;) {
 436                         rethandle = NULL;
 437                         ret = acpi_get_next_object(ACPI_TYPE_DEVICE,
 438                                                    phandle, chandle,
 439                                                    &rethandle);
 440
 441                         if (ret == AE_NOT_FOUND || rethandle == NULL)
 442                                 break;
 443
 444                         chandle = rethandle;
 445
 446                         ret = acpi_evaluate_integer(chandle, METHOD_NAME__ADR,
 447                                                     NULL, &adr);
 448
 449                         if (ACPI_SUCCESS(ret) &&
 450                             (adr>>16) == (slot->device_num + 1)) {
 451
 452                                 ret = acpi_bus_add(&device, pdevice, chandle,
 453                                                    ACPI_BUS_TYPE_DEVICE);
 454                                 if (ACPI_FAILURE(ret)) {
 455                                         printk(KERN_ERR "%s: acpi_bus_add "
 456                                                "failed (0x%x) for slot %d "
 457                                                "func %d\n", __func__,
 458                                                ret, (int)(adr>>16),
 459                                                (int)(adr&0xffff));
 460                                         /* try to continue on */
 461                                 } else {
 462                                         acpi_bus_start(device);
 463                                 }
 464                         }
 465                 }
 466         }
 467
 468         /* Call the driver for the new device */
 469         pci_bus_add_devices(slot->pci_bus);
 470         /* Call the drivers for the new devices subordinate to PPB */
 471         if (new_ppb)
 472                 pci_bus_add_devices(new_bus);
 473
 474         mutex_unlock(&sn_hotplug_mutex);
 475
 476         if (rc == 0)
 477                 dev_dbg(&slot->pci_bus->self->dev,
 478                         "insert operation successful\n");
 479         else
 480                 dev_dbg(&slot->pci_bus->self->dev,
 481                         "insert operation failed rc = %d\n", rc);
 482
 483         return rc;
 484 }
 485
 486 static int disable_slot(struct hotplug_slot *bss_hotplug_slot)
 487 {
 488         struct slot *slot = bss_hotplug_slot->private;
 489         struct pci_dev *dev;
 490         int func;
 491         int rc;
 492         acpi_owner_id ssdt_id = 0;
 493
 494         /* Acquire update access to the bus */
 495         mutex_lock(&sn_hotplug_mutex);
 496
 497         /* is it okay to bring this slot down? */
 498         rc = sn_slot_disable(bss_hotplug_slot, slot->device_num,
 499                              PCI_REQ_SLOT_ELIGIBLE);
 500         if (rc)
 501                 goto leaving;
 502
 503         /* free the ACPI resources for the slot */
 504         if (SN_ACPI_BASE_SUPPORT() &&
 505             PCI_CONTROLLER(slot->pci_bus)->acpi_handle) {
 506                 unsigned long long adr;
 507                 struct acpi_device *device;
 508                 acpi_handle phandle;
 509                 acpi_handle chandle = NULL;
 510                 acpi_handle rethandle;
 511                 acpi_status ret;
 512
 513                 /* Get the rootbus node pointer */
 514                 phandle = PCI_CONTROLLER(slot->pci_bus)->acpi_handle;
 515
 516                 /*
 517                  * Walk the rootbus node's immediate children looking for
 518                  * the slot's device node(s). There can be more than
 519                  * one for multifunction devices.
 520                  */
 521                 for (;;) {
 522                         rethandle = NULL;
 523                         ret = acpi_get_next_object(ACPI_TYPE_DEVICE,
 524                                                    phandle, chandle,
 525                                                    &rethandle);
 526
 527                         if (ret == AE_NOT_FOUND || rethandle == NULL)
 528                                 break;
 529
 530                         chandle = rethandle;
 531
 532                         ret = acpi_evaluate_integer(chandle,
 533                                                     METHOD_NAME__ADR,
 534                                                     NULL, &adr);
 535                         if (ACPI_SUCCESS(ret) &&
 536                             (adr>>16) == (slot->device_num + 1)) {
 537                                 /* retain the owner id */
 538                                 acpi_get_id(chandle, &ssdt_id);
 539
 540                                 ret = acpi_bus_get_device(chandle,
 541                                                           &device);
 542                                 if (ACPI_SUCCESS(ret))
 543                                         acpi_bus_trim(device, 1);
 544                         }
 545                 }
 546
 547         }
 548
 549         /* Free the SN resources assigned to the Linux device.*/
 550         for (func = 0; func < 8;  func++) {
 551                 dev = pci_get_slot(slot->pci_bus,
 552                                    PCI_DEVFN(slot->device_num + 1,
 553                                              PCI_FUNC(func)));
 554                 if (dev) {
 555                         sn_bus_free_data(dev);
 556                         pci_remove_bus_device(dev);
 557                         pci_dev_put(dev);
 558                 }
 559         }
 560
 561         /* Remove the SSDT for the slot from the ACPI namespace */
 562         if (SN_ACPI_BASE_SUPPORT() && ssdt_id) {
 563                 acpi_status ret;
 564                 ret = acpi_unload_table_id(ssdt_id);
 565                 if (ACPI_FAILURE(ret)) {
 566                         printk(KERN_ERR "%s: acpi_unload_table_id "
 567                                "failed (0x%x) for id %d\n",
 568                                __func__, ret, ssdt_id);
 569                         /* try to continue on */
 570                 }
 571         }
 572
 573         /* free the collected sysdata pointers */
 574         sn_bus_free_sysdata();
 575
 576         /* Deactivate slot */
 577         rc = sn_slot_disable(bss_hotplug_slot, slot->device_num,
 578                              PCI_REQ_SLOT_DISABLE);
 579  leaving:
 580         /* Release the bus lock */
 581         mutex_unlock(&sn_hotplug_mutex);
 582
 583         return rc;
 584 }
 585
 586 static inline int get_power_status(struct hotplug_slot *bss_hotplug_slot,
 587                                    u8 *value)
 588 {
 589         struct slot *slot = bss_hotplug_slot->private;
 590         struct pcibus_info *pcibus_info;
 591         u32 power;
 592
 593         pcibus_info = SN_PCIBUS_BUSSOFT_INFO(slot->pci_bus);
 594         mutex_lock(&sn_hotplug_mutex);
 595         power = pcibus_info->pbi_enabled_devices & (1 << slot->device_num);
 596         *value = power ? 1 : 0;
 597         mutex_unlock(&sn_hotplug_mutex);
 598         return 0;
 599 }
 600
 601 static void sn_release_slot(struct hotplug_slot *bss_hotplug_slot)
 602 {
 603         kfree(bss_hotplug_slot->info);
 604         kfree(bss_hotplug_slot->private);
 605         kfree(bss_hotplug_slot);
 606 }
 607
 608 static int sn_hotplug_slot_register(struct pci_bus *pci_bus)
 609 {
 610         int device;
 611         struct pci_slot *pci_slot;
 612         struct hotplug_slot *bss_hotplug_slot;
 613         char name[SN_SLOT_NAME_SIZE];
 614         int rc = 0;
 615
 616         /*
 617          * Currently only four devices are supported,
 618          * in the future there maybe more -- up to 32.
 619          */
 620
 621         for (device = 0; device < SN_MAX_HP_SLOTS ; device++) {
 622                 if (sn_pci_slot_valid(pci_bus, device) != 1)
 623                         continue;
 624
 625                 bss_hotplug_slot = kzalloc(sizeof(*bss_hotplug_slot),
 626                                            GFP_KERNEL);
 627                 if (!bss_hotplug_slot) {
 628                         rc = -ENOMEM;
 629                         goto alloc_err;
 630                 }
 631
 632                 bss_hotplug_slot->info =
 633                         kzalloc(sizeof(struct hotplug_slot_info),
 634                                 GFP_KERNEL);
 635                 if (!bss_hotplug_slot->info) {
 636                         rc = -ENOMEM;
 637                         goto alloc_err;
 638                 }
 639
 640                 if (sn_hp_slot_private_alloc(bss_hotplug_slot,
 641                                              pci_bus, device, name)) {
 642                         rc = -ENOMEM;
 643                         goto alloc_err;
 644                 }
 645                 bss_hotplug_slot->ops = &sn_hotplug_slot_ops;
 646                 bss_hotplug_slot->release = &sn_release_slot;
 647
 648                 rc = pci_hp_register(bss_hotplug_slot, pci_bus, device, name);
 649                 if (rc)
 650                         goto register_err;
 651
 652                 pci_slot = bss_hotplug_slot->pci_slot;
 653                 rc = sysfs_create_file(&pci_slot->kobj,
 654                                        &sn_slot_path_attr.attr);
 655                 if (rc)
 656                         goto register_err;
 657         }
 658         dev_dbg(&pci_bus->self->dev, "Registered bus with hotplug\n");
 659         return rc;
 660
 661 register_err:
 662         dev_dbg(&pci_bus->self->dev, "bus failed to register with err = %d\n",
 663                 rc);
 664
 665 alloc_err:
 666         if (rc == -ENOMEM)
 667                 dev_dbg(&pci_bus->self->dev, "Memory allocation error\n");
 668
 669         /* destroy THIS element */
 670         if (bss_hotplug_slot)
 671                 sn_release_slot(bss_hotplug_slot);
 672
 673         /* destroy anything else on the list */
 674         while ((bss_hotplug_slot = sn_hp_destroy()))
 675                 pci_hp_deregister(bss_hotplug_slot);
 676
 677         return rc;
 678 }
 679
 680 static int __init sn_pci_hotplug_init(void)
 681 {
 682         struct pci_bus *pci_bus = NULL;
 683         int rc;
 684         int registered = 0;
 685
 686         if (!sn_prom_feature_available(PRF_HOTPLUG_SUPPORT)) {
 687                 printk(KERN_ERR "%s: PROM version does not support hotplug.\n",
 688                        __func__);
 689                 return -EPERM;
 690         }
 691
 692         INIT_LIST_HEAD(&sn_hp_list);
 693
 694         while ((pci_bus = pci_find_next_bus(pci_bus))) {
 695                 if (!pci_bus->sysdata)
 696                         continue;
 697
 698                 rc = sn_pci_bus_valid(pci_bus);
 699                 if (rc != 1) {
 700                         dev_dbg(&pci_bus->self->dev, "not a valid hotplug bus\n");
 701                         continue;
 702                 }
 703                 dev_dbg(&pci_bus->self->dev, "valid hotplug bus\n");
 704
 705                 rc = sn_hotplug_slot_register(pci_bus);
 706                 if (!rc) {
 707                         registered = 1;
 708                 } else {
 709                         registered = 0;
 710                         break;
 711                 }
 712         }
 713
 714         return registered == 1 ? 0 : -ENODEV;
 715 }
 716
 717 static void __exit sn_pci_hotplug_exit(void)
 718 {
 719         struct hotplug_slot *bss_hotplug_slot;
 720
 721         while ((bss_hotplug_slot = sn_hp_destroy()))
 722                 pci_hp_deregister(bss_hotplug_slot);
 723
 724         if (!list_empty(&sn_hp_list))
 725                 printk(KERN_ERR "%s: internal list is not empty\n", __FILE__);
 726 }
 727
 728 module_init(sn_pci_hotplug_init);
 729 module_exit(sn_pci_hotplug_exit);