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 slot *slot)
 199 {
 200         kfree(slot->hotplug_slot->info);
 201         kfree(slot->hotplug_slot);
 202         pci_dev_put(slot->dev);
 203         kfree(slot);
 204 }
 205
 206 #define SLOT_NAME_SIZE  6
 207
 208 int
 209 cpci_hp_register_bus(struct pci_bus *bus, u8 first, u8 last)
 210 {
 211         struct slot *slot;
 212         struct hotplug_slot *hotplug_slot;
 213         struct hotplug_slot_info *info;
 214         char name[SLOT_NAME_SIZE];
 215         int status;
 216         int i;
 217
 218         if (!(controller && bus))
 219                 return -ENODEV;
 220
 221         /*
 222          * Create a structure for each slot, and register that slot
 223          * with the pci_hotplug subsystem.
 224          */
 225         for (i = first; i <= last; ++i) {
 226                 slot = kzalloc(sizeof(struct slot), GFP_KERNEL);
 227                 if (!slot) {
 228                         status = -ENOMEM;
 229                         goto error;
 230                 }
 231
 232                 hotplug_slot =
 233                         kzalloc(sizeof(struct hotplug_slot), GFP_KERNEL);
 234                 if (!hotplug_slot) {
 235                         status = -ENOMEM;
 236                         goto error_slot;
 237                 }
 238                 slot->hotplug_slot = hotplug_slot;
 239
 240                 info = kzalloc(sizeof(struct hotplug_slot_info), GFP_KERNEL);
 241                 if (!info) {
 242                         status = -ENOMEM;
 243                         goto error_hpslot;
 244                 }
 245                 hotplug_slot->info = info;
 246
 247                 slot->bus = bus;
 248                 slot->number = i;
 249                 slot->devfn = PCI_DEVFN(i, 0);
 250
 251                 snprintf(name, SLOT_NAME_SIZE, "%02x:%02x", bus->number, i);
 252
 253                 hotplug_slot->private = slot;
 254                 hotplug_slot->ops = &cpci_hotplug_slot_ops;
 255
 256                 /*
 257                  * Initialize the slot info structure with some known
 258                  * good values.
 259                  */
 260                 dbg("initializing slot %s", name);
 261                 info->power_status = cpci_get_power_status(slot);
 262                 info->attention_status = cpci_get_attention_status(slot);
 263
 264                 dbg("registering slot %s", name);
 265                 status = pci_hp_register(slot->hotplug_slot, bus, i, name);
 266                 if (status) {
 267                         err("pci_hp_register failed with error %d", status);
 268                         goto error_info;
 269                 }
 270                 dbg("slot registered with name: %s", slot_name(slot));
 271
 272                 /* Add slot to our internal list */
 273                 down_write(&list_rwsem);
 274                 list_add(&slot->slot_list, &slot_list);
 275                 slots++;
 276                 up_write(&list_rwsem);
 277         }
 278         return 0;
 279 error_info:
 280         kfree(info);
 281 error_hpslot:
 282         kfree(hotplug_slot);
 283 error_slot:
 284         kfree(slot);
 285 error:
 286         return status;
 287 }
 288 EXPORT_SYMBOL_GPL(cpci_hp_register_bus);
 289
 290 int
 291 cpci_hp_unregister_bus(struct pci_bus *bus)
 292 {
 293         struct slot *slot;
 294         struct slot *tmp;
 295         int status = 0;
 296
 297         down_write(&list_rwsem);
 298         if (!slots) {
 299                 up_write(&list_rwsem);
 300                 return -1;
 301         }
 302         list_for_each_entry_safe(slot, tmp, &slot_list, slot_list) {
 303                 if (slot->bus == bus) {
 304                         list_del(&slot->slot_list);
 305                         slots--;
 306
 307                         dbg("deregistering slot %s", slot_name(slot));
 308                         pci_hp_deregister(slot->hotplug_slot);
 309                         release_slot(slot);
 310                 }
 311         }
 312         up_write(&list_rwsem);
 313         return status;
 314 }
 315 EXPORT_SYMBOL_GPL(cpci_hp_unregister_bus);
 316
 317 /* This is the interrupt mode interrupt handler */
 318 static irqreturn_t
 319 cpci_hp_intr(int irq, void *data)
 320 {
 321         dbg("entered cpci_hp_intr");
 322
 323         /* Check to see if it was our interrupt */
 324         if ((controller->irq_flags & IRQF_SHARED) &&
 325             !controller->ops->check_irq(controller->dev_id)) {
 326                 dbg("exited cpci_hp_intr, not our interrupt");
 327                 return IRQ_NONE;
 328         }
 329
 330         /* Disable ENUM interrupt */
 331         controller->ops->disable_irq();
 332
 333         /* Trigger processing by the event thread */
 334         wake_up_process(cpci_thread);
 335         return IRQ_HANDLED;
 336 }
 337
 338 /*
 339  * According to PICMG 2.1 R2.0, section 6.3.2, upon
 340  * initialization, the system driver shall clear the
 341  * INS bits of the cold-inserted devices.
 342  */
 343 static int
 344 init_slots(int clear_ins)
 345 {
 346         struct slot *slot;
 347         struct pci_dev *dev;
 348
 349         dbg("%s - enter", __func__);
 350         down_read(&list_rwsem);
 351         if (!slots) {
 352                 up_read(&list_rwsem);
 353                 return -1;
 354         }
 355         list_for_each_entry(slot, &slot_list, slot_list) {
 356                 dbg("%s - looking at slot %s", __func__, slot_name(slot));
 357                 if (clear_ins && cpci_check_and_clear_ins(slot))
 358                         dbg("%s - cleared INS for slot %s",
 359                             __func__, slot_name(slot));
 360                 dev = pci_get_slot(slot->bus, PCI_DEVFN(slot->number, 0));
 361                 if (dev) {
 362                         if (update_adapter_status(slot->hotplug_slot, 1))
 363                                 warn("failure to update adapter file");
 364                         if (update_latch_status(slot->hotplug_slot, 1))
 365                                 warn("failure to update latch file");
 366                         slot->dev = dev;
 367                 }
 368         }
 369         up_read(&list_rwsem);
 370         dbg("%s - exit", __func__);
 371         return 0;
 372 }
 373
 374 static int
 375 check_slots(void)
 376 {
 377         struct slot *slot;
 378         int extracted;
 379         int inserted;
 380         u16 hs_csr;
 381
 382         down_read(&list_rwsem);
 383         if (!slots) {
 384                 up_read(&list_rwsem);
 385                 err("no slots registered, shutting down");
 386                 return -1;
 387         }
 388         extracted = inserted = 0;
 389         list_for_each_entry(slot, &slot_list, slot_list) {
 390                 dbg("%s - looking at slot %s", __func__, slot_name(slot));
 391                 if (cpci_check_and_clear_ins(slot)) {
 392                         /*
 393                          * Some broken hardware (e.g. PLX 9054AB) asserts
 394                          * ENUM# twice...
 395                          */
 396                         if (slot->dev) {
 397                                 warn("slot %s already inserted",
 398                                      slot_name(slot));
 399                                 inserted++;
 400                                 continue;
 401                         }
 402
 403                         /* Process insertion */
 404                         dbg("%s - slot %s inserted", __func__, slot_name(slot));
 405
 406                         /* GSM, debug */
 407                         hs_csr = cpci_get_hs_csr(slot);
 408                         dbg("%s - slot %s HS_CSR (1) = %04x",
 409                             __func__, slot_name(slot), hs_csr);
 410
 411                         /* Configure device */
 412                         dbg("%s - configuring slot %s",
 413                             __func__, slot_name(slot));
 414                         if (cpci_configure_slot(slot)) {
 415                                 err("%s - could not configure slot %s",
 416                                     __func__, slot_name(slot));
 417                                 continue;
 418                         }
 419                         dbg("%s - finished configuring slot %s",
 420                             __func__, slot_name(slot));
 421
 422                         /* GSM, debug */
 423                         hs_csr = cpci_get_hs_csr(slot);
 424                         dbg("%s - slot %s HS_CSR (2) = %04x",
 425                             __func__, slot_name(slot), hs_csr);
 426
 427                         if (update_latch_status(slot->hotplug_slot, 1))
 428                                 warn("failure to update latch file");
 429
 430                         if (update_adapter_status(slot->hotplug_slot, 1))
 431                                 warn("failure to update adapter file");
 432
 433                         cpci_led_off(slot);
 434
 435                         /* GSM, debug */
 436                         hs_csr = cpci_get_hs_csr(slot);
 437                         dbg("%s - slot %s HS_CSR (3) = %04x",
 438                             __func__, slot_name(slot), hs_csr);
 439
 440                         inserted++;
 441                 } else if (cpci_check_ext(slot)) {
 442                         /* Process extraction request */
 443                         dbg("%s - slot %s extracted",
 444                             __func__, slot_name(slot));
 445
 446                         /* GSM, debug */
 447                         hs_csr = cpci_get_hs_csr(slot);
 448                         dbg("%s - slot %s HS_CSR = %04x",
 449                             __func__, slot_name(slot), hs_csr);
 450
 451                         if (!slot->extracting) {
 452                                 if (update_latch_status(slot->hotplug_slot, 0))
 453                                         warn("failure to update latch file");
 454
 455                                 slot->extracting = 1;
 456                                 atomic_inc(&extracting);
 457                         }
 458                         extracted++;
 459                 } else if (slot->extracting) {
 460                         hs_csr = cpci_get_hs_csr(slot);
 461                         if (hs_csr == 0xffff) {
 462                                 /*
 463                                  * Hmmm, we're likely hosed at this point, should we
 464                                  * bother trying to tell the driver or not?
 465                                  */
 466                                 err("card in slot %s was improperly removed",
 467                                     slot_name(slot));
 468                                 if (update_adapter_status(slot->hotplug_slot, 0))
 469                                         warn("failure to update adapter file");
 470                                 slot->extracting = 0;
 471                                 atomic_dec(&extracting);
 472                         }
 473                 }
 474         }
 475         up_read(&list_rwsem);
 476         dbg("inserted=%d, extracted=%d, extracting=%d",
 477             inserted, extracted, atomic_read(&extracting));
 478         if (inserted || extracted)
 479                 return extracted;
 480         else if (!atomic_read(&extracting)) {
 481                 err("cannot find ENUM# source, shutting down");
 482                 return -1;
 483         }
 484         return 0;
 485 }
 486
 487 /* This is the interrupt mode worker thread body */
 488 static int
 489 event_thread(void *data)
 490 {
 491         int rc;
 492
 493         dbg("%s - event thread started", __func__);
 494         while (1) {
 495                 dbg("event thread sleeping");
 496                 set_current_state(TASK_INTERRUPTIBLE);
 497                 schedule();
 498                 if (kthread_should_stop())
 499                         break;
 500                 do {
 501                         rc = check_slots();
 502                         if (rc > 0) {
 503                                 /* Give userspace a chance to handle extraction */
 504                                 msleep(500);
 505                         } else if (rc < 0) {
 506                                 dbg("%s - error checking slots", __func__);
 507                                 thread_finished = 1;
 508                                 goto out;
 509                         }
 510                 } while (atomic_read(&extracting) && !kthread_should_stop());
 511                 if (kthread_should_stop())
 512                         break;
 513
 514                 /* Re-enable ENUM# interrupt */
 515                 dbg("%s - re-enabling irq", __func__);
 516                 controller->ops->enable_irq();
 517         }
 518  out:
 519         return 0;
 520 }
 521
 522 /* This is the polling mode worker thread body */
 523 static int
 524 poll_thread(void *data)
 525 {
 526         int rc;
 527
 528         while (1) {
 529                 if (kthread_should_stop() || signal_pending(current))
 530                         break;
 531                 if (controller->ops->query_enum()) {
 532                         do {
 533                                 rc = check_slots();
 534                                 if (rc > 0) {
 535                                         /* Give userspace a chance to handle extraction */
 536                                         msleep(500);
 537                                 } else if (rc < 0) {
 538                                         dbg("%s - error checking slots", __func__);
 539                                         thread_finished = 1;
 540                                         goto out;
 541                                 }
 542                         } while (atomic_read(&extracting) && !kthread_should_stop());
 543                 }
 544                 msleep(100);
 545         }
 546  out:
 547         return 0;
 548 }
 549
 550 static int
 551 cpci_start_thread(void)
 552 {
 553         if (controller->irq)
 554                 cpci_thread = kthread_run(event_thread, NULL, "cpci_hp_eventd");
 555         else
 556                 cpci_thread = kthread_run(poll_thread, NULL, "cpci_hp_polld");
 557         if (IS_ERR(cpci_thread)) {
 558                 err("Can't start up our thread");
 559                 return PTR_ERR(cpci_thread);
 560         }
 561         thread_finished = 0;
 562         return 0;
 563 }
 564
 565 static void
 566 cpci_stop_thread(void)
 567 {
 568         kthread_stop(cpci_thread);
 569         thread_finished = 1;
 570 }
 571
 572 int
 573 cpci_hp_register_controller(struct cpci_hp_controller *new_controller)
 574 {
 575         int status = 0;
 576
 577         if (controller)
 578                 return -1;
 579         if (!(new_controller && new_controller->ops))
 580                 return -EINVAL;
 581         if (new_controller->irq) {
 582                 if (!(new_controller->ops->enable_irq &&
 583                      new_controller->ops->disable_irq))
 584                         status = -EINVAL;
 585                 if (request_irq(new_controller->irq,
 586                                cpci_hp_intr,
 587                                new_controller->irq_flags,
 588                                MY_NAME,
 589                                new_controller->dev_id)) {
 590                         err("Can't get irq %d for the hotplug cPCI controller",
 591                             new_controller->irq);
 592                         status = -ENODEV;
 593                 }
 594                 dbg("%s - acquired controller irq %d",
 595                     __func__, new_controller->irq);
 596         }
 597         if (!status)
 598                 controller = new_controller;
 599         return status;
 600 }
 601 EXPORT_SYMBOL_GPL(cpci_hp_register_controller);
 602
 603 static void
 604 cleanup_slots(void)
 605 {
 606         struct slot *slot;
 607         struct slot *tmp;
 608
 609         /*
 610          * Unregister all of our slots with the pci_hotplug subsystem,
 611          * and free up all memory that we had allocated.
 612          */
 613         down_write(&list_rwsem);
 614         if (!slots)
 615                 goto cleanup_null;
 616         list_for_each_entry_safe(slot, tmp, &slot_list, slot_list) {
 617                 list_del(&slot->slot_list);
 618                 pci_hp_deregister(slot->hotplug_slot);
 619                 release_slot(slot);
 620         }
 621 cleanup_null:
 622         up_write(&list_rwsem);
 623         return;
 624 }
 625
 626 int
 627 cpci_hp_unregister_controller(struct cpci_hp_controller *old_controller)
 628 {
 629         int status = 0;
 630
 631         if (controller) {
 632                 if (!thread_finished)
 633                         cpci_stop_thread();
 634                 if (controller->irq)
 635                         free_irq(controller->irq, controller->dev_id);
 636                 controller = NULL;
 637                 cleanup_slots();
 638         } else
 639                 status = -ENODEV;
 640         return status;
 641 }
 642 EXPORT_SYMBOL_GPL(cpci_hp_unregister_controller);
 643
 644 int
 645 cpci_hp_start(void)
 646 {
 647         static int first = 1;
 648         int status;
 649
 650         dbg("%s - enter", __func__);
 651         if (!controller)
 652                 return -ENODEV;
 653
 654         down_read(&list_rwsem);
 655         if (list_empty(&slot_list)) {
 656                 up_read(&list_rwsem);
 657                 return -ENODEV;
 658         }
 659         up_read(&list_rwsem);
 660
 661         status = init_slots(first);
 662         if (first)
 663                 first = 0;
 664         if (status)
 665                 return status;
 666
 667         status = cpci_start_thread();
 668         if (status)
 669                 return status;
 670         dbg("%s - thread started", __func__);
 671
 672         if (controller->irq) {
 673                 /* Start enum interrupt processing */
 674                 dbg("%s - enabling irq", __func__);
 675                 controller->ops->enable_irq();
 676         }
 677         dbg("%s - exit", __func__);
 678         return 0;
 679 }
 680 EXPORT_SYMBOL_GPL(cpci_hp_start);
 681
 682 int
 683 cpci_hp_stop(void)
 684 {
 685         if (!controller)
 686                 return -ENODEV;
 687         if (controller->irq) {
 688                 /* Stop enum interrupt processing */
 689                 dbg("%s - disabling irq", __func__);
 690                 controller->ops->disable_irq();
 691         }
 692         cpci_stop_thread();
 693         return 0;
 694 }
 695 EXPORT_SYMBOL_GPL(cpci_hp_stop);
 696
 697 int __init
 698 cpci_hotplug_init(int debug)
 699 {
 700         cpci_debug = debug;
 701         return 0;
 702 }