drivers/pci/hotplug/pciehp_ctrl.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * PCI Express Hot Plug Controller Driver
   4  *
   5  * Copyright (C) 1995,2001 Compaq Computer Corporation
   6  * Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
   7  * Copyright (C) 2001 IBM Corp.
   8  * Copyright (C) 2003-2004 Intel Corporation
   9  *
  10  * All rights reserved.
  11  *
  12  * Send feedback to <greg@kroah.com>, <kristen.c.accardi@intel.com>
  13  *
  14  */
  15
  16 #define dev_fmt(fmt) "pciehp: " fmt
  17
  18 #include <linux/kernel.h>
  19 #include <linux/types.h>
  20 #include <linux/pm_runtime.h>
  21 #include <linux/pci.h>
  22 #include "pciehp.h"
  23
  24 /* The following routines constitute the bulk of the
  25    hotplug controller logic
  26  */
  27
  28 #define SAFE_REMOVAL     true
  29 #define SURPRISE_REMOVAL false
  30
  31 static void set_slot_off(struct controller *ctrl)
  32 {
  33         /*
  34          * Turn off slot, turn on attention indicator, turn off power
  35          * indicator
  36          */
  37         if (POWER_CTRL(ctrl)) {
  38                 pciehp_power_off_slot(ctrl);
  39
  40                 /*
  41                  * After turning power off, we must wait for at least 1 second
  42                  * before taking any action that relies on power having been
  43                  * removed from the slot/adapter.
  44                  */
  45                 msleep(1000);
  46         }
  47
  48         pciehp_set_indicators(ctrl, PCI_EXP_SLTCTL_PWR_IND_OFF,
  49                               PCI_EXP_SLTCTL_ATTN_IND_ON);
  50 }
  51
  52 /**
  53  * board_added - Called after a board has been added to the system.
  54  * @ctrl: PCIe hotplug controller where board is added
  55  *
  56  * Turns power on for the board.
  57  * Configures board.
  58  */
  59 static int board_added(struct controller *ctrl)
  60 {
  61         int retval = 0;
  62         struct pci_bus *parent = ctrl->pcie->port->subordinate;
  63
  64         if (POWER_CTRL(ctrl)) {
  65                 /* Power on slot */
  66                 retval = pciehp_power_on_slot(ctrl);
  67                 if (retval)
  68                         return retval;
  69         }
  70
  71         pciehp_set_indicators(ctrl, PCI_EXP_SLTCTL_PWR_IND_BLINK,
  72                               INDICATOR_NOOP);
  73
  74         /* Check link training status */
  75         retval = pciehp_check_link_status(ctrl);
  76         if (retval)
  77                 goto err_exit;
  78
  79         /* Check for a power fault */
  80         if (ctrl->power_fault_detected || pciehp_query_power_fault(ctrl)) {
  81                 ctrl_err(ctrl, "Slot(%s): Power fault\n", slot_name(ctrl));
  82                 retval = -EIO;
  83                 goto err_exit;
  84         }
  85
  86         retval = pciehp_configure_device(ctrl);
  87         if (retval) {
  88                 if (retval != -EEXIST) {
  89                         ctrl_err(ctrl, "Cannot add device at %04x:%02x:00\n",
  90                                  pci_domain_nr(parent), parent->number);
  91                         goto err_exit;
  92                 }
  93         }
  94
  95         pciehp_set_indicators(ctrl, PCI_EXP_SLTCTL_PWR_IND_ON,
  96                               PCI_EXP_SLTCTL_ATTN_IND_OFF);
  97         return 0;
  98
  99 err_exit:
 100         set_slot_off(ctrl);
 101         return retval;
 102 }
 103
 104 /**
 105  * remove_board - Turn off slot and Power Indicator
 106  * @ctrl: PCIe hotplug controller where board is being removed
 107  * @safe_removal: whether the board is safely removed (versus surprise removed)
 108  */
 109 static void remove_board(struct controller *ctrl, bool safe_removal)
 110 {
 111         pciehp_unconfigure_device(ctrl, safe_removal);
 112
 113         if (POWER_CTRL(ctrl)) {
 114                 pciehp_power_off_slot(ctrl);
 115
 116                 /*
 117                  * After turning power off, we must wait for at least 1 second
 118                  * before taking any action that relies on power having been
 119                  * removed from the slot/adapter.
 120                  */
 121                 msleep(1000);
 122
 123                 /* Ignore link or presence changes caused by power off */
 124                 atomic_and(~(PCI_EXP_SLTSTA_DLLSC | PCI_EXP_SLTSTA_PDC),
 125                            &ctrl->pending_events);
 126         }
 127
 128         pciehp_set_indicators(ctrl, PCI_EXP_SLTCTL_PWR_IND_OFF,
 129                               INDICATOR_NOOP);
 130 }
 131
 132 static int pciehp_enable_slot(struct controller *ctrl);
 133 static int pciehp_disable_slot(struct controller *ctrl, bool safe_removal);
 134
 135 void pciehp_request(struct controller *ctrl, int action)
 136 {
 137         atomic_or(action, &ctrl->pending_events);
 138         if (!pciehp_poll_mode)
 139                 irq_wake_thread(ctrl->pcie->irq, ctrl);
 140 }
 141
 142 void pciehp_queue_pushbutton_work(struct work_struct *work)
 143 {
 144         struct controller *ctrl = container_of(work, struct controller,
 145                                                button_work.work);
 146
 147         mutex_lock(&ctrl->state_lock);
 148         switch (ctrl->state) {
 149         case BLINKINGOFF_STATE:
 150                 pciehp_request(ctrl, DISABLE_SLOT);
 151                 break;
 152         case BLINKINGON_STATE:
 153                 pciehp_request(ctrl, PCI_EXP_SLTSTA_PDC);
 154                 break;
 155         default:
 156                 break;
 157         }
 158         mutex_unlock(&ctrl->state_lock);
 159 }
 160
 161 void pciehp_handle_button_press(struct controller *ctrl)
 162 {
 163         mutex_lock(&ctrl->state_lock);
 164         switch (ctrl->state) {
 165         case OFF_STATE:
 166         case ON_STATE:
 167                 if (ctrl->state == ON_STATE) {
 168                         ctrl->state = BLINKINGOFF_STATE;
 169                         ctrl_info(ctrl, "Slot(%s): Powering off due to button press\n",
 170                                   slot_name(ctrl));
 171                 } else {
 172                         ctrl->state = BLINKINGON_STATE;
 173                         ctrl_info(ctrl, "Slot(%s) Powering on due to button press\n",
 174                                   slot_name(ctrl));
 175                 }
 176                 /* blink power indicator and turn off attention */
 177                 pciehp_set_indicators(ctrl, PCI_EXP_SLTCTL_PWR_IND_BLINK,
 178                                       PCI_EXP_SLTCTL_ATTN_IND_OFF);
 179                 schedule_delayed_work(&ctrl->button_work, 5 * HZ);
 180                 break;
 181         case BLINKINGOFF_STATE:
 182         case BLINKINGON_STATE:
 183                 /*
 184                  * Cancel if we are still blinking; this means that we
 185                  * press the attention again before the 5 sec. limit
 186                  * expires to cancel hot-add or hot-remove
 187                  */
 188                 ctrl_info(ctrl, "Slot(%s): Button cancel\n", slot_name(ctrl));
 189                 cancel_delayed_work(&ctrl->button_work);
 190                 if (ctrl->state == BLINKINGOFF_STATE) {
 191                         ctrl->state = ON_STATE;
 192                         pciehp_set_indicators(ctrl, PCI_EXP_SLTCTL_PWR_IND_ON,
 193                                               PCI_EXP_SLTCTL_ATTN_IND_OFF);
 194                 } else {
 195                         ctrl->state = OFF_STATE;
 196                         pciehp_set_indicators(ctrl, PCI_EXP_SLTCTL_PWR_IND_OFF,
 197                                               PCI_EXP_SLTCTL_ATTN_IND_OFF);
 198                 }
 199                 ctrl_info(ctrl, "Slot(%s): Action canceled due to button press\n",
 200                           slot_name(ctrl));
 201                 break;
 202         default:
 203                 ctrl_err(ctrl, "Slot(%s): Ignoring invalid state %#x\n",
 204                          slot_name(ctrl), ctrl->state);
 205                 break;
 206         }
 207         mutex_unlock(&ctrl->state_lock);
 208 }
 209
 210 void pciehp_handle_disable_request(struct controller *ctrl)
 211 {
 212         mutex_lock(&ctrl->state_lock);
 213         switch (ctrl->state) {
 214         case BLINKINGON_STATE:
 215         case BLINKINGOFF_STATE:
 216                 cancel_delayed_work(&ctrl->button_work);
 217                 break;
 218         }
 219         ctrl->state = POWEROFF_STATE;
 220         mutex_unlock(&ctrl->state_lock);
 221
 222         ctrl->request_result = pciehp_disable_slot(ctrl, SAFE_REMOVAL);
 223 }
 224
 225 void pciehp_handle_presence_or_link_change(struct controller *ctrl, u32 events)
 226 {
 227         int present, link_active;
 228
 229         /*
 230          * If the slot is on and presence or link has changed, turn it off.
 231          * Even if it's occupied again, we cannot assume the card is the same.
 232          */
 233         mutex_lock(&ctrl->state_lock);
 234         switch (ctrl->state) {
 235         case BLINKINGOFF_STATE:
 236                 cancel_delayed_work(&ctrl->button_work);
 237                 fallthrough;
 238         case ON_STATE:
 239                 ctrl->state = POWEROFF_STATE;
 240                 mutex_unlock(&ctrl->state_lock);
 241                 if (events & PCI_EXP_SLTSTA_DLLSC)
 242                         ctrl_info(ctrl, "Slot(%s): Link Down\n",
 243                                   slot_name(ctrl));
 244                 if (events & PCI_EXP_SLTSTA_PDC)
 245                         ctrl_info(ctrl, "Slot(%s): Card not present\n",
 246                                   slot_name(ctrl));
 247                 pciehp_disable_slot(ctrl, SURPRISE_REMOVAL);
 248                 break;
 249         default:
 250                 mutex_unlock(&ctrl->state_lock);
 251                 break;
 252         }
 253
 254         /* Turn the slot on if it's occupied or link is up */
 255         mutex_lock(&ctrl->state_lock);
 256         present = pciehp_card_present(ctrl);
 257         link_active = pciehp_check_link_active(ctrl);
 258         if (present <= 0 && link_active <= 0) {
 259                 mutex_unlock(&ctrl->state_lock);
 260                 return;
 261         }
 262
 263         switch (ctrl->state) {
 264         case BLINKINGON_STATE:
 265                 cancel_delayed_work(&ctrl->button_work);
 266                 fallthrough;
 267         case OFF_STATE:
 268                 ctrl->state = POWERON_STATE;
 269                 mutex_unlock(&ctrl->state_lock);
 270                 if (present)
 271                         ctrl_info(ctrl, "Slot(%s): Card present\n",
 272                                   slot_name(ctrl));
 273                 if (link_active)
 274                         ctrl_info(ctrl, "Slot(%s): Link Up\n",
 275                                   slot_name(ctrl));
 276                 ctrl->request_result = pciehp_enable_slot(ctrl);
 277                 break;
 278         default:
 279                 mutex_unlock(&ctrl->state_lock);
 280                 break;
 281         }
 282 }
 283
 284 static int __pciehp_enable_slot(struct controller *ctrl)
 285 {
 286         u8 getstatus = 0;
 287
 288         if (MRL_SENS(ctrl)) {
 289                 pciehp_get_latch_status(ctrl, &getstatus);
 290                 if (getstatus) {
 291                         ctrl_info(ctrl, "Slot(%s): Latch open\n",
 292                                   slot_name(ctrl));
 293                         return -ENODEV;
 294                 }
 295         }
 296
 297         if (POWER_CTRL(ctrl)) {
 298                 pciehp_get_power_status(ctrl, &getstatus);
 299                 if (getstatus) {
 300                         ctrl_info(ctrl, "Slot(%s): Already enabled\n",
 301                                   slot_name(ctrl));
 302                         return 0;
 303                 }
 304         }
 305
 306         return board_added(ctrl);
 307 }
 308
 309 static int pciehp_enable_slot(struct controller *ctrl)
 310 {
 311         int ret;
 312
 313         pm_runtime_get_sync(&ctrl->pcie->port->dev);
 314         ret = __pciehp_enable_slot(ctrl);
 315         if (ret && ATTN_BUTTN(ctrl))
 316                 /* may be blinking */
 317                 pciehp_set_indicators(ctrl, PCI_EXP_SLTCTL_PWR_IND_OFF,
 318                                       INDICATOR_NOOP);
 319         pm_runtime_put(&ctrl->pcie->port->dev);
 320
 321         mutex_lock(&ctrl->state_lock);
 322         ctrl->state = ret ? OFF_STATE : ON_STATE;
 323         mutex_unlock(&ctrl->state_lock);
 324
 325         return ret;
 326 }
 327
 328 static int __pciehp_disable_slot(struct controller *ctrl, bool safe_removal)
 329 {
 330         u8 getstatus = 0;
 331
 332         if (POWER_CTRL(ctrl)) {
 333                 pciehp_get_power_status(ctrl, &getstatus);
 334                 if (!getstatus) {
 335                         ctrl_info(ctrl, "Slot(%s): Already disabled\n",
 336                                   slot_name(ctrl));
 337                         return -EINVAL;
 338                 }
 339         }
 340
 341         remove_board(ctrl, safe_removal);
 342         return 0;
 343 }
 344
 345 static int pciehp_disable_slot(struct controller *ctrl, bool safe_removal)
 346 {
 347         int ret;
 348
 349         pm_runtime_get_sync(&ctrl->pcie->port->dev);
 350         ret = __pciehp_disable_slot(ctrl, safe_removal);
 351         pm_runtime_put(&ctrl->pcie->port->dev);
 352
 353         mutex_lock(&ctrl->state_lock);
 354         ctrl->state = OFF_STATE;
 355         mutex_unlock(&ctrl->state_lock);
 356
 357         return ret;
 358 }
 359
 360 int pciehp_sysfs_enable_slot(struct hotplug_slot *hotplug_slot)
 361 {
 362         struct controller *ctrl = to_ctrl(hotplug_slot);
 363
 364         mutex_lock(&ctrl->state_lock);
 365         switch (ctrl->state) {
 366         case BLINKINGON_STATE:
 367         case OFF_STATE:
 368                 mutex_unlock(&ctrl->state_lock);
 369                 /*
 370                  * The IRQ thread becomes a no-op if the user pulls out the
 371                  * card before the thread wakes up, so initialize to -ENODEV.
 372                  */
 373                 ctrl->request_result = -ENODEV;
 374                 pciehp_request(ctrl, PCI_EXP_SLTSTA_PDC);
 375                 wait_event(ctrl->requester,
 376                            !atomic_read(&ctrl->pending_events) &&
 377                            !ctrl->ist_running);
 378                 return ctrl->request_result;
 379         case POWERON_STATE:
 380                 ctrl_info(ctrl, "Slot(%s): Already in powering on state\n",
 381                           slot_name(ctrl));
 382                 break;
 383         case BLINKINGOFF_STATE:
 384         case ON_STATE:
 385         case POWEROFF_STATE:
 386                 ctrl_info(ctrl, "Slot(%s): Already enabled\n",
 387                           slot_name(ctrl));
 388                 break;
 389         default:
 390                 ctrl_err(ctrl, "Slot(%s): Invalid state %#x\n",
 391                          slot_name(ctrl), ctrl->state);
 392                 break;
 393         }
 394         mutex_unlock(&ctrl->state_lock);
 395
 396         return -ENODEV;
 397 }
 398
 399 int pciehp_sysfs_disable_slot(struct hotplug_slot *hotplug_slot)
 400 {
 401         struct controller *ctrl = to_ctrl(hotplug_slot);
 402
 403         mutex_lock(&ctrl->state_lock);
 404         switch (ctrl->state) {
 405         case BLINKINGOFF_STATE:
 406         case ON_STATE:
 407                 mutex_unlock(&ctrl->state_lock);
 408                 pciehp_request(ctrl, DISABLE_SLOT);
 409                 wait_event(ctrl->requester,
 410                            !atomic_read(&ctrl->pending_events) &&
 411                            !ctrl->ist_running);
 412                 return ctrl->request_result;
 413         case POWEROFF_STATE:
 414                 ctrl_info(ctrl, "Slot(%s): Already in powering off state\n",
 415                           slot_name(ctrl));
 416                 break;
 417         case BLINKINGON_STATE:
 418         case OFF_STATE:
 419         case POWERON_STATE:
 420                 ctrl_info(ctrl, "Slot(%s): Already disabled\n",
 421                           slot_name(ctrl));
 422                 break;
 423         default:
 424                 ctrl_err(ctrl, "Slot(%s): Invalid state %#x\n",
 425                          slot_name(ctrl), ctrl->state);
 426                 break;
 427         }
 428         mutex_unlock(&ctrl->state_lock);
 429
 430         return -ENODEV;
 431 }