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->reset_work);
  95         cancel_work_sync(&dev->bus_rescan_work);
  96
  97         cancel_delayed_work_sync(&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         mei_clear_interrupts(dev);
 126
 127         /* we're already in reset, cancel the init timer
 128          * if the reset was called due the hbm protocol error
 129          * we need to call it before hw start
 130          * so the hbm watchdog won't kick in
 131          */
 132         mei_hbm_idle(dev);
 133
 134         /* enter reset flow */
 135         interrupts_enabled = state != MEI_DEV_POWER_DOWN;
 136         dev->dev_state = MEI_DEV_RESETTING;
 137
 138         dev->reset_count++;
 139         if (dev->reset_count > MEI_MAX_CONSEC_RESET) {
 140                 dev_err(dev->dev, "reset: reached maximal consecutive resets: disabling the device\n");
 141                 dev->dev_state = MEI_DEV_DISABLED;
 142                 return -ENODEV;
 143         }
 144
 145         ret = mei_hw_reset(dev, interrupts_enabled);
 146         /* fall through and remove the sw state even if hw reset has failed */
 147
 148         /* no need to clean up software state in case of power up */
 149         if (state != MEI_DEV_INITIALIZING && state != MEI_DEV_POWER_UP)
 150                 mei_cl_all_disconnect(dev);
 151
 152         mei_hbm_reset(dev);
 153
 154         dev->rd_msg_hdr = 0;
 155
 156         if (ret) {
 157                 dev_err(dev->dev, "hw_reset failed ret = %d\n", ret);
 158                 return ret;
 159         }
 160
 161         if (state == MEI_DEV_POWER_DOWN) {
 162                 dev_dbg(dev->dev, "powering down: end of reset\n");
 163                 dev->dev_state = MEI_DEV_DISABLED;
 164                 return 0;
 165         }
 166
 167         ret = mei_hw_start(dev);
 168         if (ret) {
 169                 dev_err(dev->dev, "hw_start failed ret = %d\n", ret);
 170                 return ret;
 171         }
 172
 173         dev_dbg(dev->dev, "link is established start sending messages.\n");
 174
 175         dev->dev_state = MEI_DEV_INIT_CLIENTS;
 176         ret = mei_hbm_start_req(dev);
 177         if (ret) {
 178                 dev_err(dev->dev, "hbm_start failed ret = %d\n", ret);
 179                 dev->dev_state = MEI_DEV_RESETTING;
 180                 return ret;
 181         }
 182
 183         return 0;
 184 }
 185 EXPORT_SYMBOL_GPL(mei_reset);
 186
 187 /**
 188  * mei_start - initializes host and fw to start work.
 189  *
 190  * @dev: the device structure
 191  *
 192  * Return: 0 on success, <0 on failure.
 193  */
 194 int mei_start(struct mei_device *dev)
 195 {
 196         int ret;
 197
 198         mutex_lock(&dev->device_lock);
 199
 200         /* acknowledge interrupt and stop interrupts */
 201         mei_clear_interrupts(dev);
 202
 203         mei_hw_config(dev);
 204
 205         dev_dbg(dev->dev, "reset in start the mei device.\n");
 206
 207         dev->reset_count = 0;
 208         do {
 209                 dev->dev_state = MEI_DEV_INITIALIZING;
 210                 ret = mei_reset(dev);
 211
 212                 if (ret == -ENODEV || dev->dev_state == MEI_DEV_DISABLED) {
 213                         dev_err(dev->dev, "reset failed ret = %d", ret);
 214                         goto err;
 215                 }
 216         } while (ret);
 217
 218         /* we cannot start the device w/o hbm start message completed */
 219         if (dev->dev_state == MEI_DEV_DISABLED) {
 220                 dev_err(dev->dev, "reset failed");
 221                 goto err;
 222         }
 223
 224         if (mei_hbm_start_wait(dev)) {
 225                 dev_err(dev->dev, "HBM haven't started");
 226                 goto err;
 227         }
 228
 229         if (!mei_host_is_ready(dev)) {
 230                 dev_err(dev->dev, "host is not ready.\n");
 231                 goto err;
 232         }
 233
 234         if (!mei_hw_is_ready(dev)) {
 235                 dev_err(dev->dev, "ME is not ready.\n");
 236                 goto err;
 237         }
 238
 239         if (!mei_hbm_version_is_supported(dev)) {
 240                 dev_dbg(dev->dev, "MEI start failed.\n");
 241                 goto err;
 242         }
 243
 244         dev_dbg(dev->dev, "link layer has been established.\n");
 245
 246         mutex_unlock(&dev->device_lock);
 247         return 0;
 248 err:
 249         dev_err(dev->dev, "link layer initialization failed.\n");
 250         dev->dev_state = MEI_DEV_DISABLED;
 251         mutex_unlock(&dev->device_lock);
 252         return -ENODEV;
 253 }
 254 EXPORT_SYMBOL_GPL(mei_start);
 255
 256 /**
 257  * mei_restart - restart device after suspend
 258  *
 259  * @dev: the device structure
 260  *
 261  * Return: 0 on success or -ENODEV if the restart hasn't succeeded
 262  */
 263 int mei_restart(struct mei_device *dev)
 264 {
 265         int err;
 266
 267         mutex_lock(&dev->device_lock);
 268
 269         dev->dev_state = MEI_DEV_POWER_UP;
 270         dev->reset_count = 0;
 271
 272         err = mei_reset(dev);
 273
 274         mutex_unlock(&dev->device_lock);
 275
 276         if (err == -ENODEV || dev->dev_state == MEI_DEV_DISABLED) {
 277                 dev_err(dev->dev, "device disabled = %d\n", err);
 278                 return -ENODEV;
 279         }
 280
 281         /* try to start again */
 282         if (err)
 283                 schedule_work(&dev->reset_work);
 284
 285
 286         return 0;
 287 }
 288 EXPORT_SYMBOL_GPL(mei_restart);
 289
 290 static void mei_reset_work(struct work_struct *work)
 291 {
 292         struct mei_device *dev =
 293                 container_of(work, struct mei_device,  reset_work);
 294         int ret;
 295
 296         mei_clear_interrupts(dev);
 297         mei_synchronize_irq(dev);
 298
 299         mutex_lock(&dev->device_lock);
 300
 301         ret = mei_reset(dev);
 302
 303         mutex_unlock(&dev->device_lock);
 304
 305         if (dev->dev_state == MEI_DEV_DISABLED) {
 306                 dev_err(dev->dev, "device disabled = %d\n", ret);
 307                 return;
 308         }
 309
 310         /* retry reset in case of failure */
 311         if (ret)
 312                 schedule_work(&dev->reset_work);
 313 }
 314
 315 void mei_stop(struct mei_device *dev)
 316 {
 317         dev_dbg(dev->dev, "stopping the device.\n");
 318
 319         mei_cl_bus_remove_devices(dev);
 320
 321         mei_cancel_work(dev);
 322
 323         mei_clear_interrupts(dev);
 324         mei_synchronize_irq(dev);
 325
 326         mutex_lock(&dev->device_lock);
 327
 328         dev->dev_state = MEI_DEV_POWER_DOWN;
 329         mei_reset(dev);
 330         /* move device to disabled state unconditionally */
 331         dev->dev_state = MEI_DEV_DISABLED;
 332
 333         mutex_unlock(&dev->device_lock);
 334 }
 335 EXPORT_SYMBOL_GPL(mei_stop);
 336
 337 /**
 338  * mei_write_is_idle - check if the write queues are idle
 339  *
 340  * @dev: the device structure
 341  *
 342  * Return: true of there is no pending write
 343  */
 344 bool mei_write_is_idle(struct mei_device *dev)
 345 {
 346         bool idle = (dev->dev_state == MEI_DEV_ENABLED &&
 347                 list_empty(&dev->ctrl_wr_list) &&
 348                 list_empty(&dev->write_list)   &&
 349                 list_empty(&dev->write_waiting_list));
 350
 351         dev_dbg(dev->dev, "write pg: is idle[%d] state=%s ctrl=%01d write=%01d wwait=%01d\n",
 352                 idle,
 353                 mei_dev_state_str(dev->dev_state),
 354                 list_empty(&dev->ctrl_wr_list),
 355                 list_empty(&dev->write_list),
 356                 list_empty(&dev->write_waiting_list));
 357
 358         return idle;
 359 }
 360 EXPORT_SYMBOL_GPL(mei_write_is_idle);
 361
 362 /**
 363  * mei_device_init  -- initialize mei_device structure
 364  *
 365  * @dev: the mei device
 366  * @device: the device structure
 367  * @hw_ops: hw operations
 368  */
 369 void mei_device_init(struct mei_device *dev,
 370                      struct device *device,
 371                      const struct mei_hw_ops *hw_ops)
 372 {
 373         /* setup our list array */
 374         INIT_LIST_HEAD(&dev->file_list);
 375         INIT_LIST_HEAD(&dev->device_list);
 376         INIT_LIST_HEAD(&dev->me_clients);
 377         mutex_init(&dev->device_lock);
 378         init_rwsem(&dev->me_clients_rwsem);
 379         mutex_init(&dev->cl_bus_lock);
 380         init_waitqueue_head(&dev->wait_hw_ready);
 381         init_waitqueue_head(&dev->wait_pg);
 382         init_waitqueue_head(&dev->wait_hbm_start);
 383         dev->dev_state = MEI_DEV_INITIALIZING;
 384         dev->reset_count = 0;
 385
 386         INIT_LIST_HEAD(&dev->write_list);
 387         INIT_LIST_HEAD(&dev->write_waiting_list);
 388         INIT_LIST_HEAD(&dev->ctrl_wr_list);
 389         INIT_LIST_HEAD(&dev->ctrl_rd_list);
 390
 391         INIT_DELAYED_WORK(&dev->timer_work, mei_timer);
 392         INIT_WORK(&dev->reset_work, mei_reset_work);
 393         INIT_WORK(&dev->bus_rescan_work, mei_cl_bus_rescan_work);
 394
 395         bitmap_zero(dev->host_clients_map, MEI_CLIENTS_MAX);
 396         dev->open_handle_count = 0;
 397
 398         /*
 399          * Reserving the first client ID
 400          * 0: Reserved for MEI Bus Message communications
 401          */
 402         bitmap_set(dev->host_clients_map, 0, 1);
 403
 404         dev->pg_event = MEI_PG_EVENT_IDLE;
 405         dev->ops      = hw_ops;
 406         dev->dev      = device;
 407 }
 408 EXPORT_SYMBOL_GPL(mei_device_init);
 409