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