LXR linux/drivers/pci/hotplug/pciehp

   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
  31static 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 */
  59static 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
  99err_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 */
 109static 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
 132static int pciehp_enable_slot(struct controller *ctrl);
 133static int pciehp_disable_slot(struct controller *ctrl, bool safe_removal);
 134
 135void 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
 142void 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
 161void 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
 210void 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
 225void 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
 284static 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
 309static 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
 328static 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
 345static 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
 360int 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
 399int 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}
 432