drivers/misc/mei/wd.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 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/moduleparam.h>
  19 #include <linux/device.h>
  20 #include <linux/pci.h>
  21 #include <linux/sched.h>
  22 #include <linux/watchdog.h>
  23
  24 #include <linux/mei.h>
  25
  26 #include "mei_dev.h"
  27 #include "hbm.h"
  28 #include "client.h"
  29
  30 static const u8 mei_start_wd_params[] = { 0x02, 0x12, 0x13, 0x10 };
  31 static const u8 mei_stop_wd_params[] = { 0x02, 0x02, 0x14, 0x10 };
  32
  33 /*
  34  * AMT Watchdog Device
  35  */
  36 #define INTEL_AMT_WATCHDOG_ID "INTCAMT"
  37
  38 /* UUIDs for AMT F/W clients */
  39 const uuid_le mei_wd_guid = UUID_LE(0x05B79A6F, 0x4628, 0x4D7F, 0x89,
  40                                                 0x9D, 0xA9, 0x15, 0x14, 0xCB,
  41                                                 0x32, 0xAB);
  42
  43 static void mei_wd_set_start_timeout(struct mei_device *dev, u16 timeout)
  44 {
  45         dev_dbg(&dev->pdev->dev, "wd: set timeout=%d.\n", timeout);
  46         memcpy(dev->wd_data, mei_start_wd_params, MEI_WD_HDR_SIZE);
  47         memcpy(dev->wd_data + MEI_WD_HDR_SIZE, &timeout, sizeof(u16));
  48 }
  49
  50 /**
  51  * mei_wd_host_init - connect to the watchdog client
  52  *
  53  * @dev: the device structure
  54  *
  55  * returns -ENOTTY if wd client cannot be found
  56  *         -EIO if write has failed
  57  *         0 on success
  58  */
  59 int mei_wd_host_init(struct mei_device *dev)
  60 {
  61         struct mei_cl *cl = &dev->wd_cl;
  62         int id;
  63         int ret;
  64
  65         mei_cl_init(cl, dev);
  66
  67         dev->wd_timeout = MEI_WD_DEFAULT_TIMEOUT;
  68         dev->wd_state = MEI_WD_IDLE;
  69
  70
  71         /* check for valid client id */
  72         id = mei_me_cl_by_uuid(dev, &mei_wd_guid);
  73         if (id < 0) {
  74                 dev_info(&dev->pdev->dev, "wd: failed to find the client\n");
  75                 return -ENOTTY;
  76         }
  77
  78         cl->me_client_id = dev->me_clients[id].client_id;
  79
  80         ret = mei_cl_link(cl, MEI_WD_HOST_CLIENT_ID);
  81
  82         if (ret < 0) {
  83                 dev_info(&dev->pdev->dev, "wd: failed link client\n");
  84                 return ret;
  85         }
  86
  87         cl->state = MEI_FILE_CONNECTING;
  88
  89         ret = mei_cl_connect(cl, NULL);
  90
  91         if (ret) {
  92                 dev_err(&dev->pdev->dev, "wd: failed to connect = %d\n", ret);
  93                 mei_cl_unlink(cl);
  94                 return ret;
  95         }
  96
  97         ret = mei_watchdog_register(dev);
  98         if (ret) {
  99                 mei_cl_disconnect(cl);
 100                 mei_cl_unlink(cl);
 101         }
 102         return ret;
 103 }
 104
 105 /**
 106  * mei_wd_send - sends watch dog message to fw.
 107  *
 108  * @dev: the device structure
 109  *
 110  * returns 0 if success,
 111  *      -EIO when message send fails
 112  *      -EINVAL when invalid message is to be sent
 113  *      -ENODEV on flow control failure
 114  */
 115 int mei_wd_send(struct mei_device *dev)
 116 {
 117         struct mei_cl *cl = &dev->wd_cl;
 118         struct mei_msg_hdr hdr;
 119         int ret;
 120
 121         hdr.host_addr = cl->host_client_id;
 122         hdr.me_addr = cl->me_client_id;
 123         hdr.msg_complete = 1;
 124         hdr.reserved = 0;
 125         hdr.internal = 0;
 126
 127         if (!memcmp(dev->wd_data, mei_start_wd_params, MEI_WD_HDR_SIZE))
 128                 hdr.length = MEI_WD_START_MSG_SIZE;
 129         else if (!memcmp(dev->wd_data, mei_stop_wd_params, MEI_WD_HDR_SIZE))
 130                 hdr.length = MEI_WD_STOP_MSG_SIZE;
 131         else {
 132                 dev_err(&dev->pdev->dev, "wd: invalid message is to be sent, aborting\n");
 133                 return -EINVAL;
 134         }
 135
 136         ret = mei_write_message(dev, &hdr, dev->wd_data);
 137         if (ret) {
 138                 dev_err(&dev->pdev->dev, "wd: write message failed\n");
 139                 return ret;
 140         }
 141
 142         ret = mei_cl_flow_ctrl_reduce(cl);
 143         if (ret) {
 144                 dev_err(&dev->pdev->dev, "wd: flow_ctrl_reduce failed.\n");
 145                 return ret;
 146         }
 147
 148         return 0;
 149 }
 150
 151 /**
 152  * mei_wd_stop - sends watchdog stop message to fw.
 153  *
 154  * @dev: the device structure
 155  * @preserve: indicate if to keep the timeout value
 156  *
 157  * returns 0 if success
 158  * on error:
 159  *      -EIO    when message send fails
 160  *      -EINVAL when invalid message is to be sent
 161  *      -ETIME  on message timeout
 162  */
 163 int mei_wd_stop(struct mei_device *dev)
 164 {
 165         int ret;
 166
 167         if (dev->wd_cl.state != MEI_FILE_CONNECTED ||
 168             dev->wd_state != MEI_WD_RUNNING)
 169                 return 0;
 170
 171         memcpy(dev->wd_data, mei_stop_wd_params, MEI_WD_STOP_MSG_SIZE);
 172
 173         dev->wd_state = MEI_WD_STOPPING;
 174
 175         ret = mei_cl_flow_ctrl_creds(&dev->wd_cl);
 176         if (ret < 0)
 177                 goto err;
 178
 179         if (ret && mei_hbuf_acquire(dev)) {
 180                 ret = mei_wd_send(dev);
 181                 if (ret)
 182                         goto err;
 183                 dev->wd_pending = false;
 184         } else {
 185                 dev->wd_pending = true;
 186         }
 187
 188         mutex_unlock(&dev->device_lock);
 189
 190         ret = wait_event_timeout(dev->wait_stop_wd,
 191                                 dev->wd_state == MEI_WD_IDLE,
 192                                 msecs_to_jiffies(MEI_WD_STOP_TIMEOUT));
 193         mutex_lock(&dev->device_lock);
 194         if (dev->wd_state != MEI_WD_IDLE) {
 195                 /* timeout */
 196                 ret = -ETIME;
 197                 dev_warn(&dev->pdev->dev,
 198                         "wd: stop failed to complete ret=%d.\n", ret);
 199                 goto err;
 200         }
 201         dev_dbg(&dev->pdev->dev, "wd: stop completed after %u msec\n",
 202                         MEI_WD_STOP_TIMEOUT - jiffies_to_msecs(ret));
 203         return 0;
 204 err:
 205         return ret;
 206 }
 207
 208 /*
 209  * mei_wd_ops_start - wd start command from the watchdog core.
 210  *
 211  * @wd_dev - watchdog device struct
 212  *
 213  * returns 0 if success, negative errno code for failure
 214  */
 215 static int mei_wd_ops_start(struct watchdog_device *wd_dev)
 216 {
 217         int err = -ENODEV;
 218         struct mei_device *dev;
 219
 220         dev = watchdog_get_drvdata(wd_dev);
 221         if (!dev)
 222                 return -ENODEV;
 223
 224         mutex_lock(&dev->device_lock);
 225
 226         if (dev->dev_state != MEI_DEV_ENABLED) {
 227                 dev_dbg(&dev->pdev->dev,
 228                         "wd: dev_state != MEI_DEV_ENABLED  dev_state = %s\n",
 229                         mei_dev_state_str(dev->dev_state));
 230                 goto end_unlock;
 231         }
 232
 233         if (dev->wd_cl.state != MEI_FILE_CONNECTED)     {
 234                 dev_dbg(&dev->pdev->dev,
 235                         "MEI Driver is not connected to Watchdog Client\n");
 236                 goto end_unlock;
 237         }
 238
 239         mei_wd_set_start_timeout(dev, dev->wd_timeout);
 240
 241         err = 0;
 242 end_unlock:
 243         mutex_unlock(&dev->device_lock);
 244         return err;
 245 }
 246
 247 /*
 248  * mei_wd_ops_stop -  wd stop command from the watchdog core.
 249  *
 250  * @wd_dev - watchdog device struct
 251  *
 252  * returns 0 if success, negative errno code for failure
 253  */
 254 static int mei_wd_ops_stop(struct watchdog_device *wd_dev)
 255 {
 256         struct mei_device *dev;
 257
 258         dev = watchdog_get_drvdata(wd_dev);
 259         if (!dev)
 260                 return -ENODEV;
 261
 262         mutex_lock(&dev->device_lock);
 263         mei_wd_stop(dev);
 264         mutex_unlock(&dev->device_lock);
 265
 266         return 0;
 267 }
 268
 269 /*
 270  * mei_wd_ops_ping - wd ping command from the watchdog core.
 271  *
 272  * @wd_dev - watchdog device struct
 273  *
 274  * returns 0 if success, negative errno code for failure
 275  */
 276 static int mei_wd_ops_ping(struct watchdog_device *wd_dev)
 277 {
 278         struct mei_device *dev;
 279         int ret;
 280
 281         dev = watchdog_get_drvdata(wd_dev);
 282         if (!dev)
 283                 return -ENODEV;
 284
 285         mutex_lock(&dev->device_lock);
 286
 287         if (dev->wd_cl.state != MEI_FILE_CONNECTED) {
 288                 dev_err(&dev->pdev->dev, "wd: not connected.\n");
 289                 ret = -ENODEV;
 290                 goto end;
 291         }
 292
 293         dev->wd_state = MEI_WD_RUNNING;
 294
 295         ret = mei_cl_flow_ctrl_creds(&dev->wd_cl);
 296         if (ret < 0)
 297                 goto end;
 298         /* Check if we can send the ping to HW*/
 299         if (ret && mei_hbuf_acquire(dev)) {
 300
 301                 dev_dbg(&dev->pdev->dev, "wd: sending ping\n");
 302
 303                 ret = mei_wd_send(dev);
 304                 if (ret)
 305                         goto end;
 306                 dev->wd_pending = false;
 307         } else {
 308                 dev->wd_pending = true;
 309         }
 310
 311 end:
 312         mutex_unlock(&dev->device_lock);
 313         return ret;
 314 }
 315
 316 /*
 317  * mei_wd_ops_set_timeout - wd set timeout command from the watchdog core.
 318  *
 319  * @wd_dev - watchdog device struct
 320  * @timeout - timeout value to set
 321  *
 322  * returns 0 if success, negative errno code for failure
 323  */
 324 static int mei_wd_ops_set_timeout(struct watchdog_device *wd_dev,
 325                 unsigned int timeout)
 326 {
 327         struct mei_device *dev;
 328
 329         dev = watchdog_get_drvdata(wd_dev);
 330         if (!dev)
 331                 return -ENODEV;
 332
 333         /* Check Timeout value */
 334         if (timeout < MEI_WD_MIN_TIMEOUT || timeout > MEI_WD_MAX_TIMEOUT)
 335                 return -EINVAL;
 336
 337         mutex_lock(&dev->device_lock);
 338
 339         dev->wd_timeout = timeout;
 340         wd_dev->timeout = timeout;
 341         mei_wd_set_start_timeout(dev, dev->wd_timeout);
 342
 343         mutex_unlock(&dev->device_lock);
 344
 345         return 0;
 346 }
 347
 348 /*
 349  * Watchdog Device structs
 350  */
 351 static const struct watchdog_ops wd_ops = {
 352                 .owner = THIS_MODULE,
 353                 .start = mei_wd_ops_start,
 354                 .stop = mei_wd_ops_stop,
 355                 .ping = mei_wd_ops_ping,
 356                 .set_timeout = mei_wd_ops_set_timeout,
 357 };
 358 static const struct watchdog_info wd_info = {
 359                 .identity = INTEL_AMT_WATCHDOG_ID,
 360                 .options = WDIOF_KEEPALIVEPING |
 361                            WDIOF_SETTIMEOUT |
 362                            WDIOF_ALARMONLY,
 363 };
 364
 365 static struct watchdog_device amt_wd_dev = {
 366                 .info = &wd_info,
 367                 .ops = &wd_ops,
 368                 .timeout = MEI_WD_DEFAULT_TIMEOUT,
 369                 .min_timeout = MEI_WD_MIN_TIMEOUT,
 370                 .max_timeout = MEI_WD_MAX_TIMEOUT,
 371 };
 372
 373
 374 int mei_watchdog_register(struct mei_device *dev)
 375 {
 376
 377         int ret;
 378
 379         /* unlock to perserve correct locking order */
 380         mutex_unlock(&dev->device_lock);
 381         ret = watchdog_register_device(&amt_wd_dev);
 382         mutex_lock(&dev->device_lock);
 383         if (ret) {
 384                 dev_err(&dev->pdev->dev, "wd: unable to register watchdog device = %d.\n",
 385                         ret);
 386                 return ret;
 387         }
 388
 389         dev_dbg(&dev->pdev->dev,
 390                 "wd: successfully register watchdog interface.\n");
 391         watchdog_set_drvdata(&amt_wd_dev, dev);
 392         return 0;
 393 }
 394
 395 void mei_watchdog_unregister(struct mei_device *dev)
 396 {
 397         if (watchdog_get_drvdata(&amt_wd_dev) == NULL)
 398                 return;
 399
 400         watchdog_set_drvdata(&amt_wd_dev, NULL);
 401         watchdog_unregister_device(&amt_wd_dev);
 402 }
 403