drivers/pci/hotplug/cpci_hotplug_core.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * CompactPCI Hot Plug Driver
   4  *
   5  * Copyright (C) 2002,2005 SOMA Networks, Inc.
   6  * Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
   7  * Copyright (C) 2001 IBM Corp.
   8  *
   9  * All rights reserved.
  10  *
  11  * Send feedback to <scottm@somanetworks.com>
  12  */
  13
  14 #include <linux/module.h>
  15 #include <linux/kernel.h>
  16 #include <linux/sched/signal.h>
  17 #include <linux/slab.h>
  18 #include <linux/pci.h>
  19 #include <linux/pci_hotplug.h>
  20 #include <linux/init.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/atomic.h>
  23 #include <linux/delay.h>
  24 #include <linux/kthread.h>
  25 #include "cpci_hotplug.h"
  26
  27 #define DRIVER_AUTHOR   "Scott Murray <scottm@somanetworks.com>"
  28 #define DRIVER_DESC     "CompactPCI Hot Plug Core"
  29
  30 #define MY_NAME "cpci_hotplug"
  31
  32 #define dbg(format, arg...)                                     \
  33         do {                                                    \
  34                 if (cpci_debug)                                 \
  35                         printk(KERN_DEBUG "%s: " format "\n",   \
  36                                 MY_NAME, ## arg);               \
  37         } while (0)
  38 #define err(format, arg...) printk(KERN_ERR "%s: " format "\n", MY_NAME, ## arg)
  39 #define info(format, arg...) printk(KERN_INFO "%s: " format "\n", MY_NAME, ## arg)
  40 #define warn(format, arg...) printk(KERN_WARNING "%s: " format "\n", MY_NAME, ## arg)
  41
  42 /* local variables */
  43 static DECLARE_RWSEM(list_rwsem);
  44 static LIST_HEAD(slot_list);
  45 static int slots;
  46 static atomic_t extracting;
  47 int cpci_debug;
  48 static struct cpci_hp_controller *controller;
  49 static struct task_struct *cpci_thread;
  50 static int thread_finished;
  51
  52 static int enable_slot(struct hotplug_slot *slot);
  53 static int disable_slot(struct hotplug_slot *slot);
  54 static int set_attention_status(struct hotplug_slot *slot, u8 value);
  55 static int get_power_status(struct hotplug_slot *slot, u8 *value);
  56 static int get_attention_status(struct hotplug_slot *slot, u8 *value);
  57 static int get_adapter_status(struct hotplug_slot *slot, u8 *value);
  58 static int get_latch_status(struct hotplug_slot *slot, u8 *value);
  59
  60 static struct hotplug_slot_ops cpci_hotplug_slot_ops = {
  61         .enable_slot = enable_slot,
  62         .disable_slot = disable_slot,
  63         .set_attention_status = set_attention_status,
  64         .get_power_status = get_power_status,
  65         .get_attention_status = get_attention_status,
  66         .get_adapter_status = get_adapter_status,
  67         .get_latch_status = get_latch_status,
  68 };
  69
  70 static int
  71 update_latch_status(struct hotplug_slot *hotplug_slot, u8 value)
  72 {
  73         struct hotplug_slot_info info;
  74
  75         memcpy(&info, hotplug_slot->info, sizeof(struct hotplug_slot_info));
  76         info.latch_status = value;
  77         return pci_hp_change_slot_info(hotplug_slot, &info);
  78 }
  79
  80 static int
  81 update_adapter_status(struct hotplug_slot *hotplug_slot, u8 value)
  82 {
  83         struct hotplug_slot_info info;
  84
  85         memcpy(&info, hotplug_slot->info, sizeof(struct hotplug_slot_info));
  86         info.adapter_status = value;
  87         return pci_hp_change_slot_info(hotplug_slot, &info);
  88 }
  89
  90 static int
  91 enable_slot(struct hotplug_slot *hotplug_slot)
  92 {
  93         struct slot *slot = hotplug_slot->private;
  94         int retval = 0;
  95
  96         dbg("%s - physical_slot = %s", __func__, slot_name(slot));
  97
  98         if (controller->ops->set_power)
  99                 retval = controller->ops->set_power(slot, 1);
 100         return retval;
 101 }
 102
 103 static int
 104 disable_slot(struct hotplug_slot *hotplug_slot)
 105 {
 106         struct slot *slot = hotplug_slot->private;
 107         int retval = 0;
 108
 109         dbg("%s - physical_slot = %s", __func__, slot_name(slot));
 110
 111         down_write(&list_rwsem);
 112
 113         /* Unconfigure device */
 114         dbg("%s - unconfiguring slot %s", __func__, slot_name(slot));
 115         retval = cpci_unconfigure_slot(slot);
 116         if (retval) {
 117                 err("%s - could not unconfigure slot %s",
 118                     __func__, slot_name(slot));
 119                 goto disable_error;
 120         }
 121         dbg("%s - finished unconfiguring slot %s", __func__, slot_name(slot));
 122
 123         /* Clear EXT (by setting it) */
 124         if (cpci_clear_ext(slot)) {
 125                 err("%s - could not clear EXT for slot %s",
 126                     __func__, slot_name(slot));
 127                 retval = -ENODEV;
 128                 goto disable_error;
 129         }
 130         cpci_led_on(slot);
 131
 132         if (controller->ops->set_power) {
 133                 retval = controller->ops->set_power(slot, 0);
 134                 if (retval)
 135                         goto disable_error;
 136         }
 137
 138         if (update_adapter_status(slot->hotplug_slot, 0))
 139                 warn("failure to update adapter file");
 140
 141         if (slot->extracting) {
 142                 slot->extracting = 0;
 143                 atomic_dec(&extracting);
 144         }
 145 disable_error:
 146         up_write(&list_rwsem);
 147         return retval;
 148 }
 149
 150 static u8
 151 cpci_get_power_status(struct slot *slot)
 152 {
 153         u8 power = 1;
 154
 155         if (controller->ops->get_power)
 156                 power = controller->ops->get_power(slot);
 157         return power;
 158 }
 159
 160 static int
 161 get_power_status(struct hotplug_slot *hotplug_slot, u8 *value)
 162 {
 163         struct slot *slot = hotplug_slot->private;
 164
 165         *value = cpci_get_power_status(slot);
 166         return 0;
 167 }
 168
 169 static int
 170 get_attention_status(struct hotplug_slot *hotplug_slot, u8 *value)
 171 {
 172         struct slot *slot = hotplug_slot->private;
 173
 174         *value = cpci_get_attention_status(slot);
 175         return 0;
 176 }
 177
 178 static int
 179 set_attention_status(struct hotplug_slot *hotplug_slot, u8 status)
 180 {
 181         return cpci_set_attention_status(hotplug_slot->private, status);
 182 }
 183
 184 static int
 185 get_adapter_status(struct hotplug_slot *hotplug_slot, u8 *value)
 186 {
 187         *value = hotplug_slot->info->adapter_status;
 188         return 0;
 189 }
 190
 191 static int
 192 get_latch_status(struct hotplug_slot *hotplug_slot, u8 *value)
 193 {
 194         *value = hotplug_slot->info->latch_status;
 195         return 0;
 196 }
 197
 198 static void release_slot(struct hotplug_slot *hotplug_slot)
 199 {
 200         struct slot *slot = hotplug_slot->private;
 201
 202         kfree(slot->hotplug_slot->info);
 203         kfree(slot->hotplug_slot);
 204         pci_dev_put(slot->dev);
 205         kfree(slot);
 206 }
 207
 208 #define SLOT_NAME_SIZE  6
 209
 210 int
 211 cpci_hp_register_bus(struct pci_bus *bus, u8 first, u8 last)
 212 {
 213         struct slot *slot;
 214         struct hotplug_slot *hotplug_slot;
 215         struct hotplug_slot_info *info;
 216         char name[SLOT_NAME_SIZE];
 217         int status;
 218         int i;
 219
 220         if (!(controller && bus))
 221                 return -ENODEV;
 222
 223         /*
 224          * Create a structure for each slot, and register that slot
 225          * with the pci_hotplug subsystem.
 226          */
 227         for (i = first; i <= last; ++i) {
 228                 slot = kzalloc(sizeof(struct slot), GFP_KERNEL);
 229                 if (!slot) {
 230                         status = -ENOMEM;
 231                         goto error;
 232                 }
 233
 234                 hotplug_slot =
 235                         kzalloc(sizeof(struct hotplug_slot), GFP_KERNEL);
 236                 if (!hotplug_slot) {
 237                         status = -ENOMEM;
 238                         goto error_slot;
 239                 }
 240                 slot->hotplug_slot = hotplug_slot;
 241
 242                 info = kzalloc(sizeof(struct hotplug_slot_info), GFP_KERNEL);
 243                 if (!info) {
 244                         status = -ENOMEM;
 245                         goto error_hpslot;
 246                 }
 247                 hotplug_slot->info = info;
 248
 249                 slot->bus = bus;
 250                 slot->number = i;
 251                 slot->devfn = PCI_DEVFN(i, 0);
 252
 253                 snprintf(name, SLOT_NAME_SIZE, "%02x:%02x", bus->number, i);
 254
 255                 hotplug_slot->private = slot;
 256                 hotplug_slot->release = &release_slot;
 257                 hotplug_slot->ops = &cpci_hotplug_slot_ops;
 258
 259                 /*
 260                  * Initialize the slot info structure with some known
 261                  * good values.
 262                  */
 263                 dbg("initializing slot %s", name);
 264                 info->power_status = cpci_get_power_status(slot);
 265                 info->attention_status = cpci_get_attention_status(slot);
 266
 267                 dbg("registering slot %s", name);
 268                 status = pci_hp_register(slot->hotplug_slot, bus, i, name);
 269                 if (status) {
 270                         err("pci_hp_register failed with error %d", status);
 271                         goto error_info;
 272                 }
 273                 dbg("slot registered with name: %s", slot_name(slot));
 274
 275                 /* Add slot to our internal list */
 276                 down_write(&list_rwsem);
 277                 list_add(&slot->slot_list, &slot_list);
 278                 slots++;
 279                 up_write(&list_rwsem);
 280         }
 281         return 0;
 282 error_info:
 283         kfree(info);
 284 error_hpslot:
 285         kfree(hotplug_slot);
 286 error_slot:
 287         kfree(slot);
 288 error:
 289         return status;
 290 }
 291 EXPORT_SYMBOL_GPL(cpci_hp_register_bus);
 292
 293 int
 294 cpci_hp_unregister_bus(struct pci_bus *bus)
 295 {
 296         struct slot *slot;
 297         struct slot *tmp;
 298         int status = 0;
 299
 300         down_write(&list_rwsem);
 301         if (!slots) {
 302                 up_write(&list_rwsem);
 303                 return -1;
 304         }
 305         list_for_each_entry_safe(slot, tmp, &slot_list, slot_list) {
 306                 if (slot->bus == bus) {
 307                         list_del(&slot->slot_list);
 308                         slots--;
 309
 310                         dbg("deregistering slot %s", slot_name(slot));
 311                         status = pci_hp_deregister(slot->hotplug_slot);
 312                         if (status) {
 313                                 err("pci_hp_deregister failed with error %d",
 314                                     status);
 315                                 break;
 316                         }
 317                 }
 318         }
 319         up_write(&list_rwsem);
 320         return status;
 321 }
 322 EXPORT_SYMBOL_GPL(cpci_hp_unregister_bus);
 323
 324 /* This is the interrupt mode interrupt handler */
 325 static irqreturn_t
 326 cpci_hp_intr(int irq, void *data)
 327 {
 328         dbg("entered cpci_hp_intr");
 329
 330         /* Check to see if it was our interrupt */
 331         if ((controller->irq_flags & IRQF_SHARED) &&
 332             !controller->ops->check_irq(controller->dev_id)) {
 333                 dbg("exited cpci_hp_intr, not our interrupt");
 334                 return IRQ_NONE;
 335         }
 336
 337         /* Disable ENUM interrupt */
 338         controller->ops->disable_irq();
 339
 340         /* Trigger processing by the event thread */
 341         wake_up_process(cpci_thread);
 342         return IRQ_HANDLED;
 343 }
 344
 345 /*
 346  * According to PICMG 2.1 R2.0, section 6.3.2, upon
 347  * initialization, the system driver shall clear the
 348  * INS bits of the cold-inserted devices.
 349  */
 350 static int
 351 init_slots(int clear_ins)
 352 {
 353         struct slot *slot;
 354         struct pci_dev *dev;
 355
 356         dbg("%s - enter", __func__);
 357         down_read(&list_rwsem);
 358         if (!slots) {
 359                 up_read(&list_rwsem);
 360                 return -1;
 361         }
 362         list_for_each_entry(slot, &slot_list, slot_list) {
 363                 dbg("%s - looking at slot %s", __func__, slot_name(slot));
 364                 if (clear_ins && cpci_check_and_clear_ins(slot))
 365                         dbg("%s - cleared INS for slot %s",
 366                             __func__, slot_name(slot));
 367                 dev = pci_get_slot(slot->bus, PCI_DEVFN(slot->number, 0));
 368                 if (dev) {
 369                         if (update_adapter_status(slot->hotplug_slot, 1))
 370                                 warn("failure to update adapter file");
 371                         if (update_latch_status(slot->hotplug_slot, 1))
 372                                 warn("failure to update latch file");
 373                         slot->dev = dev;
 374                 }
 375         }
 376         up_read(&list_rwsem);
 377         dbg("%s - exit", __func__);
 378         return 0;
 379 }
 380
 381 static int
 382 check_slots(void)
 383 {
 384         struct slot *slot;
 385         int extracted;
 386         int inserted;
 387         u16 hs_csr;
 388
 389         down_read(&list_rwsem);
 390         if (!slots) {
 391                 up_read(&list_rwsem);
 392                 err("no slots registered, shutting down");
 393                 return -1;
 394         }
 395         extracted = inserted = 0;
 396         list_for_each_entry(slot, &slot_list, slot_list) {
 397                 dbg("%s - looking at slot %s", __func__, slot_name(slot));
 398                 if (cpci_check_and_clear_ins(slot)) {
 399                         /*
 400                          * Some broken hardware (e.g. PLX 9054AB) asserts
 401                          * ENUM# twice...
 402                          */
 403                         if (slot->dev) {
 404                                 warn("slot %s already inserted",
 405                                      slot_name(slot));
 406                                 inserted++;
 407                                 continue;
 408                         }
 409
 410                         /* Process insertion */
 411                         dbg("%s - slot %s inserted", __func__, slot_name(slot));
 412
 413                         /* GSM, debug */
 414                         hs_csr = cpci_get_hs_csr(slot);
 415                         dbg("%s - slot %s HS_CSR (1) = %04x",
 416                             __func__, slot_name(slot), hs_csr);
 417
 418                         /* Configure device */
 419                         dbg("%s - configuring slot %s",
 420                             __func__, slot_name(slot));
 421                         if (cpci_configure_slot(slot)) {
 422                                 err("%s - could not configure slot %s",
 423                                     __func__, slot_name(slot));
 424                                 continue;
 425                         }
 426                         dbg("%s - finished configuring slot %s",
 427                             __func__, slot_name(slot));
 428
 429                         /* GSM, debug */
 430                         hs_csr = cpci_get_hs_csr(slot);
 431                         dbg("%s - slot %s HS_CSR (2) = %04x",
 432                             __func__, slot_name(slot), hs_csr);
 433
 434                         if (update_latch_status(slot->hotplug_slot, 1))
 435                                 warn("failure to update latch file");
 436
 437                         if (update_adapter_status(slot->hotplug_slot, 1))
 438                                 warn("failure to update adapter file");
 439
 440                         cpci_led_off(slot);
 441
 442                         /* GSM, debug */
 443                         hs_csr = cpci_get_hs_csr(slot);
 444                         dbg("%s - slot %s HS_CSR (3) = %04x",
 445                             __func__, slot_name(slot), hs_csr);
 446
 447                         inserted++;
 448                 } else if (cpci_check_ext(slot)) {
 449                         /* Process extraction request */
 450                         dbg("%s - slot %s extracted",
 451                             __func__, slot_name(slot));
 452
 453                         /* GSM, debug */
 454                         hs_csr = cpci_get_hs_csr(slot);
 455                         dbg("%s - slot %s HS_CSR = %04x",
 456                             __func__, slot_name(slot), hs_csr);
 457
 458                         if (!slot->extracting) {
 459                                 if (update_latch_status(slot->hotplug_slot, 0))
 460                                         warn("failure to update latch file");
 461
 462                                 slot->extracting = 1;
 463                                 atomic_inc(&extracting);
 464                         }
 465                         extracted++;
 466                 } else if (slot->extracting) {
 467                         hs_csr = cpci_get_hs_csr(slot);
 468                         if (hs_csr == 0xffff) {
 469                                 /*
 470                                  * Hmmm, we're likely hosed at this point, should we
 471                                  * bother trying to tell the driver or not?
 472                                  */
 473                                 err("card in slot %s was improperly removed",
 474                                     slot_name(slot));
 475                                 if (update_adapter_status(slot->hotplug_slot, 0))
 476                                         warn("failure to update adapter file");
 477                                 slot->extracting = 0;
 478                                 atomic_dec(&extracting);
 479                         }
 480                 }
 481         }
 482         up_read(&list_rwsem);
 483         dbg("inserted=%d, extracted=%d, extracting=%d",
 484             inserted, extracted, atomic_read(&extracting));
 485         if (inserted || extracted)
 486                 return extracted;
 487         else if (!atomic_read(&extracting)) {
 488                 err("cannot find ENUM# source, shutting down");
 489                 return -1;
 490         }
 491         return 0;
 492 }
 493
 494 /* This is the interrupt mode worker thread body */
 495 static int
 496 event_thread(void *data)
 497 {
 498         int rc;
 499
 500         dbg("%s - event thread started", __func__);
 501         while (1) {
 502                 dbg("event thread sleeping");
 503                 set_current_state(TASK_INTERRUPTIBLE);
 504                 schedule();
 505                 if (kthread_should_stop())
 506                         break;
 507                 do {
 508                         rc = check_slots();
 509                         if (rc > 0) {
 510                                 /* Give userspace a chance to handle extraction */
 511                                 msleep(500);
 512                         } else if (rc < 0) {
 513                                 dbg("%s - error checking slots", __func__);
 514                                 thread_finished = 1;
 515                                 goto out;
 516                         }
 517                 } while (atomic_read(&extracting) && !kthread_should_stop());
 518                 if (kthread_should_stop())
 519                         break;
 520
 521                 /* Re-enable ENUM# interrupt */
 522                 dbg("%s - re-enabling irq", __func__);
 523                 controller->ops->enable_irq();
 524         }
 525  out:
 526         return 0;
 527 }
 528
 529 /* This is the polling mode worker thread body */
 530 static int
 531 poll_thread(void *data)
 532 {
 533         int rc;
 534
 535         while (1) {
 536                 if (kthread_should_stop() || signal_pending(current))
 537                         break;
 538                 if (controller->ops->query_enum()) {
 539                         do {
 540                                 rc = check_slots();
 541                                 if (rc > 0) {
 542                                         /* Give userspace a chance to handle extraction */
 543                                         msleep(500);
 544                                 } else if (rc < 0) {
 545                                         dbg("%s - error checking slots", __func__);
 546                                         thread_finished = 1;
 547                                         goto out;
 548                                 }
 549                         } while (atomic_read(&extracting) && !kthread_should_stop());
 550                 }
 551                 msleep(100);
 552         }
 553  out:
 554         return 0;
 555 }
 556
 557 static int
 558 cpci_start_thread(void)
 559 {
 560         if (controller->irq)
 561                 cpci_thread = kthread_run(event_thread, NULL, "cpci_hp_eventd");
 562         else
 563                 cpci_thread = kthread_run(poll_thread, NULL, "cpci_hp_polld");
 564         if (IS_ERR(cpci_thread)) {
 565                 err("Can't start up our thread");
 566                 return PTR_ERR(cpci_thread);
 567         }
 568         thread_finished = 0;
 569         return 0;
 570 }
 571
 572 static void
 573 cpci_stop_thread(void)
 574 {
 575         kthread_stop(cpci_thread);
 576         thread_finished = 1;
 577 }
 578
 579 int
 580 cpci_hp_register_controller(struct cpci_hp_controller *new_controller)
 581 {
 582         int status = 0;
 583
 584         if (controller)
 585                 return -1;
 586         if (!(new_controller && new_controller->ops))
 587                 return -EINVAL;
 588         if (new_controller->irq) {
 589                 if (!(new_controller->ops->enable_irq &&
 590                      new_controller->ops->disable_irq))
 591                         status = -EINVAL;
 592                 if (request_irq(new_controller->irq,
 593                                cpci_hp_intr,
 594                                new_controller->irq_flags,
 595                                MY_NAME,
 596                                new_controller->dev_id)) {
 597                         err("Can't get irq %d for the hotplug cPCI controller",
 598                             new_controller->irq);
 599                         status = -ENODEV;
 600                 }
 601                 dbg("%s - acquired controller irq %d",
 602                     __func__, new_controller->irq);
 603         }
 604         if (!status)
 605                 controller = new_controller;
 606         return status;
 607 }
 608 EXPORT_SYMBOL_GPL(cpci_hp_register_controller);
 609
 610 static void
 611 cleanup_slots(void)
 612 {
 613         struct slot *slot;
 614         struct slot *tmp;
 615
 616         /*
 617          * Unregister all of our slots with the pci_hotplug subsystem,
 618          * and free up all memory that we had allocated.
 619          */
 620         down_write(&list_rwsem);
 621         if (!slots)
 622                 goto cleanup_null;
 623         list_for_each_entry_safe(slot, tmp, &slot_list, slot_list) {
 624                 list_del(&slot->slot_list);
 625                 pci_hp_deregister(slot->hotplug_slot);
 626         }
 627 cleanup_null:
 628         up_write(&list_rwsem);
 629         return;
 630 }
 631
 632 int
 633 cpci_hp_unregister_controller(struct cpci_hp_controller *old_controller)
 634 {
 635         int status = 0;
 636
 637         if (controller) {
 638                 if (!thread_finished)
 639                         cpci_stop_thread();
 640                 if (controller->irq)
 641                         free_irq(controller->irq, controller->dev_id);
 642                 controller = NULL;
 643                 cleanup_slots();
 644         } else
 645                 status = -ENODEV;
 646         return status;
 647 }
 648 EXPORT_SYMBOL_GPL(cpci_hp_unregister_controller);
 649
 650 int
 651 cpci_hp_start(void)
 652 {
 653         static int first = 1;
 654         int status;
 655
 656         dbg("%s - enter", __func__);
 657         if (!controller)
 658                 return -ENODEV;
 659
 660         down_read(&list_rwsem);
 661         if (list_empty(&slot_list)) {
 662                 up_read(&list_rwsem);
 663                 return -ENODEV;
 664         }
 665         up_read(&list_rwsem);
 666
 667         status = init_slots(first);
 668         if (first)
 669                 first = 0;
 670         if (status)
 671                 return status;
 672
 673         status = cpci_start_thread();
 674         if (status)
 675                 return status;
 676         dbg("%s - thread started", __func__);
 677
 678         if (controller->irq) {
 679                 /* Start enum interrupt processing */
 680                 dbg("%s - enabling irq", __func__);
 681                 controller->ops->enable_irq();
 682         }
 683         dbg("%s - exit", __func__);
 684         return 0;
 685 }
 686 EXPORT_SYMBOL_GPL(cpci_hp_start);
 687
 688 int
 689 cpci_hp_stop(void)
 690 {
 691         if (!controller)
 692                 return -ENODEV;
 693         if (controller->irq) {
 694                 /* Stop enum interrupt processing */
 695                 dbg("%s - disabling irq", __func__);
 696                 controller->ops->disable_irq();
 697         }
 698         cpci_stop_thread();
 699         return 0;
 700 }
 701 EXPORT_SYMBOL_GPL(cpci_hp_stop);
 702
 703 int __init
 704 cpci_hotplug_init(int debug)
 705 {
 706         cpci_debug = debug;
 707         return 0;
 708 }