drivers/misc/mei/init.c

   1 /*
   2  *
   3  * Intel Management Engine Interface (Intel MEI) Linux driver
   4  * Copyright (c) 2003-2012, Intel Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms and conditions of the GNU General Public License,
   8  * version 2, as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  */
  16
  17 #include <linux/export.h>
  18 #include <linux/sched.h>
  19 #include <linux/wait.h>
  20 #include <linux/delay.h>
  21
  22 #include <linux/mei.h>
  23
  24 #include "mei_dev.h"
  25 #include "hbm.h"
  26 #include "client.h"
  27
  28 const char *mei_dev_state_str(int state)
  29 {
  30 #define MEI_DEV_STATE(state) case MEI_DEV_##state: return #state
  31         switch (state) {
  32         MEI_DEV_STATE(INITIALIZING);
  33         MEI_DEV_STATE(INIT_CLIENTS);
  34         MEI_DEV_STATE(ENABLED);
  35         MEI_DEV_STATE(RESETTING);
  36         MEI_DEV_STATE(DISABLED);
  37         MEI_DEV_STATE(POWER_DOWN);
  38         MEI_DEV_STATE(POWER_UP);
  39         default:
  40                 return "unknown";
  41         }
  42 #undef MEI_DEV_STATE
  43 }
  44
  45 const char *mei_pg_state_str(enum mei_pg_state state)
  46 {
  47 #define MEI_PG_STATE(state) case MEI_PG_##state: return #state
  48         switch (state) {
  49         MEI_PG_STATE(OFF);
  50         MEI_PG_STATE(ON);
  51         default:
  52                 return "unknown";
  53         }
  54 #undef MEI_PG_STATE
  55 }
  56
  57 /**
  58  * mei_fw_status2str - convert fw status registers to printable string
  59  *
  60  * @fw_status:  firmware status
  61  * @buf: string buffer at minimal size MEI_FW_STATUS_STR_SZ
  62  * @len: buffer len must be >= MEI_FW_STATUS_STR_SZ
  63  *
  64  * Return: number of bytes written or -EINVAL if buffer is to small
  65  */
  66 ssize_t mei_fw_status2str(struct mei_fw_status *fw_status,
  67                           char *buf, size_t len)
  68 {
  69         ssize_t cnt = 0;
  70         int i;
  71
  72         buf[0] = '\0';
  73
  74         if (len < MEI_FW_STATUS_STR_SZ)
  75                 return -EINVAL;
  76
  77         for (i = 0; i < fw_status->count; i++)
  78                 cnt += scnprintf(buf + cnt, len - cnt, "%08X ",
  79                                 fw_status->status[i]);
  80
  81         /* drop last space */
  82         buf[cnt] = '\0';
  83         return cnt;
  84 }
  85 EXPORT_SYMBOL_GPL(mei_fw_status2str);
  86
  87 /**
  88  * mei_cancel_work - Cancel mei background jobs
  89  *
  90  * @dev: the device structure
  91  */
  92 void mei_cancel_work(struct mei_device *dev)
  93 {
  94         cancel_work_sync(&dev->init_work);
  95         cancel_work_sync(&dev->reset_work);
  96
  97         cancel_delayed_work(&dev->timer_work);
  98 }
  99 EXPORT_SYMBOL_GPL(mei_cancel_work);
 100
 101 /**
 102  * mei_reset - resets host and fw.
 103  *
 104  * @dev: the device structure
 105  *
 106  * Return: 0 on success or < 0 if the reset hasn't succeeded
 107  */
 108 int mei_reset(struct mei_device *dev)
 109 {
 110         enum mei_dev_state state = dev->dev_state;
 111         bool interrupts_enabled;
 112         int ret;
 113
 114         if (state != MEI_DEV_INITIALIZING &&
 115             state != MEI_DEV_DISABLED &&
 116             state != MEI_DEV_POWER_DOWN &&
 117             state != MEI_DEV_POWER_UP) {
 118                 char fw_sts_str[MEI_FW_STATUS_STR_SZ];
 119
 120                 mei_fw_status_str(dev, fw_sts_str, MEI_FW_STATUS_STR_SZ);
 121                 dev_warn(dev->dev, "unexpected reset: dev_state = %s fw status = %s\n",
 122                          mei_dev_state_str(state), fw_sts_str);
 123         }
 124
 125         /* we're already in reset, cancel the init timer
 126          * if the reset was called due the hbm protocol error
 127          * we need to call it before hw start
 128          * so the hbm watchdog won't kick in
 129          */
 130         mei_hbm_idle(dev);
 131
 132         /* enter reset flow */
 133         interrupts_enabled = state != MEI_DEV_POWER_DOWN;
 134         dev->dev_state = MEI_DEV_RESETTING;
 135
 136         dev->reset_count++;
 137         if (dev->reset_count > MEI_MAX_CONSEC_RESET) {
 138                 dev_err(dev->dev, "reset: reached maximal consecutive resets: disabling the device\n");
 139                 dev->dev_state = MEI_DEV_DISABLED;
 140                 return -ENODEV;
 141         }
 142
 143         ret = mei_hw_reset(dev, interrupts_enabled);
 144         /* fall through and remove the sw state even if hw reset has failed */
 145
 146         /* no need to clean up software state in case of power up */
 147         if (state != MEI_DEV_INITIALIZING &&
 148             state != MEI_DEV_POWER_UP) {
 149
 150                 /* remove all waiting requests */
 151                 mei_cl_all_write_clear(dev);
 152
 153                 mei_cl_all_disconnect(dev);
 154
 155                 /* wake up all readers and writers so they can be interrupted */
 156                 mei_cl_all_wakeup(dev);
 157
 158                 /* remove entry if already in list */
 159                 dev_dbg(dev->dev, "remove iamthif and wd from the file list.\n");
 160                 mei_cl_unlink(&dev->wd_cl);
 161                 mei_cl_unlink(&dev->iamthif_cl);
 162                 mei_amthif_reset_params(dev);
 163         }
 164
 165         mei_hbm_reset(dev);
 166
 167         dev->rd_msg_hdr = 0;
 168         dev->wd_pending = false;
 169
 170         if (ret) {
 171                 dev_err(dev->dev, "hw_reset failed ret = %d\n", ret);
 172                 return ret;
 173         }
 174
 175         if (state == MEI_DEV_POWER_DOWN) {
 176                 dev_dbg(dev->dev, "powering down: end of reset\n");
 177                 dev->dev_state = MEI_DEV_DISABLED;
 178                 return 0;
 179         }
 180
 181         ret = mei_hw_start(dev);
 182         if (ret) {
 183                 dev_err(dev->dev, "hw_start failed ret = %d\n", ret);
 184                 return ret;
 185         }
 186
 187         dev_dbg(dev->dev, "link is established start sending messages.\n");
 188
 189         dev->dev_state = MEI_DEV_INIT_CLIENTS;
 190         ret = mei_hbm_start_req(dev);
 191         if (ret) {
 192                 dev_err(dev->dev, "hbm_start failed ret = %d\n", ret);
 193                 dev->dev_state = MEI_DEV_RESETTING;
 194                 return ret;
 195         }
 196
 197         return 0;
 198 }
 199 EXPORT_SYMBOL_GPL(mei_reset);
 200
 201 /**
 202  * mei_start - initializes host and fw to start work.
 203  *
 204  * @dev: the device structure
 205  *
 206  * Return: 0 on success, <0 on failure.
 207  */
 208 int mei_start(struct mei_device *dev)
 209 {
 210         int ret;
 211
 212         mutex_lock(&dev->device_lock);
 213
 214         /* acknowledge interrupt and stop interrupts */
 215         mei_clear_interrupts(dev);
 216
 217         mei_hw_config(dev);
 218
 219         dev_dbg(dev->dev, "reset in start the mei device.\n");
 220
 221         dev->reset_count = 0;
 222         do {
 223                 dev->dev_state = MEI_DEV_INITIALIZING;
 224                 ret = mei_reset(dev);
 225
 226                 if (ret == -ENODEV || dev->dev_state == MEI_DEV_DISABLED) {
 227                         dev_err(dev->dev, "reset failed ret = %d", ret);
 228                         goto err;
 229                 }
 230         } while (ret);
 231
 232         /* we cannot start the device w/o hbm start message completed */
 233         if (dev->dev_state == MEI_DEV_DISABLED) {
 234                 dev_err(dev->dev, "reset failed");
 235                 goto err;
 236         }
 237
 238         if (mei_hbm_start_wait(dev)) {
 239                 dev_err(dev->dev, "HBM haven't started");
 240                 goto err;
 241         }
 242
 243         if (!mei_host_is_ready(dev)) {
 244                 dev_err(dev->dev, "host is not ready.\n");
 245                 goto err;
 246         }
 247
 248         if (!mei_hw_is_ready(dev)) {
 249                 dev_err(dev->dev, "ME is not ready.\n");
 250                 goto err;
 251         }
 252
 253         if (!mei_hbm_version_is_supported(dev)) {
 254                 dev_dbg(dev->dev, "MEI start failed.\n");
 255                 goto err;
 256         }
 257
 258         dev_dbg(dev->dev, "link layer has been established.\n");
 259
 260         mutex_unlock(&dev->device_lock);
 261         return 0;
 262 err:
 263         dev_err(dev->dev, "link layer initialization failed.\n");
 264         dev->dev_state = MEI_DEV_DISABLED;
 265         mutex_unlock(&dev->device_lock);
 266         return -ENODEV;
 267 }
 268 EXPORT_SYMBOL_GPL(mei_start);
 269
 270 /**
 271  * mei_restart - restart device after suspend
 272  *
 273  * @dev: the device structure
 274  *
 275  * Return: 0 on success or -ENODEV if the restart hasn't succeeded
 276  */
 277 int mei_restart(struct mei_device *dev)
 278 {
 279         int err;
 280
 281         mutex_lock(&dev->device_lock);
 282
 283         mei_clear_interrupts(dev);
 284
 285         dev->dev_state = MEI_DEV_POWER_UP;
 286         dev->reset_count = 0;
 287
 288         err = mei_reset(dev);
 289
 290         mutex_unlock(&dev->device_lock);
 291
 292         if (err == -ENODEV || dev->dev_state == MEI_DEV_DISABLED) {
 293                 dev_err(dev->dev, "device disabled = %d\n", err);
 294                 return -ENODEV;
 295         }
 296
 297         /* try to start again */
 298         if (err)
 299                 schedule_work(&dev->reset_work);
 300
 301
 302         return 0;
 303 }
 304 EXPORT_SYMBOL_GPL(mei_restart);
 305
 306 static void mei_reset_work(struct work_struct *work)
 307 {
 308         struct mei_device *dev =
 309                 container_of(work, struct mei_device,  reset_work);
 310         int ret;
 311
 312         mutex_lock(&dev->device_lock);
 313
 314         ret = mei_reset(dev);
 315
 316         mutex_unlock(&dev->device_lock);
 317
 318         if (dev->dev_state == MEI_DEV_DISABLED) {
 319                 dev_err(dev->dev, "device disabled = %d\n", ret);
 320                 return;
 321         }
 322
 323         /* retry reset in case of failure */
 324         if (ret)
 325                 schedule_work(&dev->reset_work);
 326 }
 327
 328 void mei_stop(struct mei_device *dev)
 329 {
 330         dev_dbg(dev->dev, "stopping the device.\n");
 331
 332         mei_cl_bus_remove_devices(dev);
 333
 334         mei_cancel_work(dev);
 335
 336         mutex_lock(&dev->device_lock);
 337
 338         mei_wd_stop(dev);
 339
 340         dev->dev_state = MEI_DEV_POWER_DOWN;
 341         mei_reset(dev);
 342         /* move device to disabled state unconditionally */
 343         dev->dev_state = MEI_DEV_DISABLED;
 344
 345         mutex_unlock(&dev->device_lock);
 346
 347         mei_watchdog_unregister(dev);
 348 }
 349 EXPORT_SYMBOL_GPL(mei_stop);
 350
 351 /**
 352  * mei_write_is_idle - check if the write queues are idle
 353  *
 354  * @dev: the device structure
 355  *
 356  * Return: true of there is no pending write
 357  */
 358 bool mei_write_is_idle(struct mei_device *dev)
 359 {
 360         bool idle = (dev->dev_state == MEI_DEV_ENABLED &&
 361                 list_empty(&dev->ctrl_wr_list.list) &&
 362                 list_empty(&dev->write_list.list)   &&
 363                 list_empty(&dev->write_waiting_list.list));
 364
 365         dev_dbg(dev->dev, "write pg: is idle[%d] state=%s ctrl=%01d write=%01d wwait=%01d\n",
 366                 idle,
 367                 mei_dev_state_str(dev->dev_state),
 368                 list_empty(&dev->ctrl_wr_list.list),
 369                 list_empty(&dev->write_list.list),
 370                 list_empty(&dev->write_waiting_list.list));
 371
 372         return idle;
 373 }
 374 EXPORT_SYMBOL_GPL(mei_write_is_idle);
 375
 376 /**
 377  * mei_device_init  -- initialize mei_device structure
 378  *
 379  * @dev: the mei device
 380  * @device: the device structure
 381  * @hw_ops: hw operations
 382  */
 383 void mei_device_init(struct mei_device *dev,
 384                      struct device *device,
 385                      const struct mei_hw_ops *hw_ops)
 386 {
 387         /* setup our list array */
 388         INIT_LIST_HEAD(&dev->file_list);
 389         INIT_LIST_HEAD(&dev->device_list);
 390         INIT_LIST_HEAD(&dev->me_clients);
 391         mutex_init(&dev->device_lock);
 392         init_rwsem(&dev->me_clients_rwsem);
 393         mutex_init(&dev->cl_bus_lock);
 394         init_waitqueue_head(&dev->wait_hw_ready);
 395         init_waitqueue_head(&dev->wait_pg);
 396         init_waitqueue_head(&dev->wait_hbm_start);
 397         init_waitqueue_head(&dev->wait_stop_wd);
 398         dev->dev_state = MEI_DEV_INITIALIZING;
 399         dev->reset_count = 0;
 400
 401         mei_io_list_init(&dev->write_list);
 402         mei_io_list_init(&dev->write_waiting_list);
 403         mei_io_list_init(&dev->ctrl_wr_list);
 404         mei_io_list_init(&dev->ctrl_rd_list);
 405
 406         INIT_DELAYED_WORK(&dev->timer_work, mei_timer);
 407         INIT_WORK(&dev->init_work, mei_host_client_init);
 408         INIT_WORK(&dev->reset_work, mei_reset_work);
 409
 410         INIT_LIST_HEAD(&dev->wd_cl.link);
 411         INIT_LIST_HEAD(&dev->iamthif_cl.link);
 412         mei_io_list_init(&dev->amthif_cmd_list);
 413         mei_io_list_init(&dev->amthif_rd_complete_list);
 414
 415         bitmap_zero(dev->host_clients_map, MEI_CLIENTS_MAX);
 416         dev->open_handle_count = 0;
 417
 418         /*
 419          * Reserving the first client ID
 420          * 0: Reserved for MEI Bus Message communications
 421          */
 422         bitmap_set(dev->host_clients_map, 0, 1);
 423
 424         dev->pg_event = MEI_PG_EVENT_IDLE;
 425         dev->ops      = hw_ops;
 426         dev->dev      = device;
 427 }
 428 EXPORT_SYMBOL_GPL(mei_device_init);
 429