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/sched.h>
  21 #include <linux/watchdog.h>
  22
  23 #include <linux/mei.h>
  24
  25 #include "mei_dev.h"
  26 #include "hbm.h"
  27 #include "client.h"
  28
  29 static const u8 mei_start_wd_params[] = { 0x02, 0x12, 0x13, 0x10 };
  30 static const u8 mei_stop_wd_params[] = { 0x02, 0x02, 0x14, 0x10 };
  31
  32 /*
  33  * AMT Watchdog Device
  34  */
  35 #define INTEL_AMT_WATCHDOG_ID "INTCAMT"
  36
  37 /* UUIDs for AMT F/W clients */
  38 const uuid_le mei_wd_guid = UUID_LE(0x05B79A6F, 0x4628, 0x4D7F, 0x89,
  39                                                 0x9D, 0xA9, 0x15, 0x14, 0xCB,
  40                                                 0x32, 0xAB);
  41
  42 static void mei_wd_set_start_timeout(struct mei_device *dev, u16 timeout)
  43 {
  44         dev_dbg(dev->dev, "wd: set timeout=%d.\n", timeout);
  45         memcpy(dev->wd_data, mei_start_wd_params, MEI_WD_HDR_SIZE);
  46         memcpy(dev->wd_data + MEI_WD_HDR_SIZE, &timeout, sizeof(u16));
  47 }
  48
  49 /**
  50  * mei_wd_host_init - connect to the watchdog client
  51  *
  52  * @dev: the device structure
  53  *
  54  * Return: -ENOTTY if wd client cannot be found
  55  *         -EIO if write has failed
  56  *         0 on success
  57  */
  58 int mei_wd_host_init(struct mei_device *dev)
  59 {
  60         struct mei_cl *cl = &dev->wd_cl;
  61         struct mei_me_client *me_cl;
  62         int ret;
  63
  64         mei_cl_init(cl, dev);
  65
  66         dev->wd_timeout = MEI_WD_DEFAULT_TIMEOUT;
  67         dev->wd_state = MEI_WD_IDLE;
  68
  69
  70         /* check for valid client id */
  71         me_cl = mei_me_cl_by_uuid(dev, &mei_wd_guid);
  72         if (!me_cl) {
  73                 dev_info(dev->dev, "wd: failed to find the client\n");
  74                 return -ENOTTY;
  75         }
  76
  77         cl->me_client_id = me_cl->client_id;
  78         cl->cl_uuid = me_cl->props.protocol_name;
  79         mei_me_cl_put(me_cl);
  80
  81         ret = mei_cl_link(cl, MEI_WD_HOST_CLIENT_ID);
  82
  83         if (ret < 0) {
  84                 dev_info(dev->dev, "wd: failed link client\n");
  85                 return ret;
  86         }
  87
  88         ret = mei_cl_connect(cl, NULL);
  89
  90         if (ret) {
  91                 dev_err(dev->dev, "wd: failed to connect = %d\n", ret);
  92                 mei_cl_unlink(cl);
  93                 return ret;
  94         }
  95
  96         ret = mei_watchdog_register(dev);
  97         if (ret) {
  98                 mei_cl_disconnect(cl);
  99                 mei_cl_unlink(cl);
 100         }
 101         return ret;
 102 }
 103
 104 /**
 105  * mei_wd_send - sends watch dog message to fw.
 106  *
 107  * @dev: the device structure
 108  *
 109  * Return: 0 if success,
 110  *      -EIO when message send fails
 111  *      -EINVAL when invalid message is to be sent
 112  *      -ENODEV on flow control failure
 113  */
 114 int mei_wd_send(struct mei_device *dev)
 115 {
 116         struct mei_cl *cl = &dev->wd_cl;
 117         struct mei_msg_hdr hdr;
 118         int ret;
 119
 120         hdr.host_addr = cl->host_client_id;
 121         hdr.me_addr = cl->me_client_id;
 122         hdr.msg_complete = 1;
 123         hdr.reserved = 0;
 124         hdr.internal = 0;
 125
 126         if (!memcmp(dev->wd_data, mei_start_wd_params, MEI_WD_HDR_SIZE))
 127                 hdr.length = MEI_WD_START_MSG_SIZE;
 128         else if (!memcmp(dev->wd_data, mei_stop_wd_params, MEI_WD_HDR_SIZE))
 129                 hdr.length = MEI_WD_STOP_MSG_SIZE;
 130         else {
 131                 dev_err(dev->dev, "wd: invalid message is to be sent, aborting\n");
 132                 return -EINVAL;
 133         }
 134
 135         ret = mei_write_message(dev, &hdr, dev->wd_data);
 136         if (ret) {
 137                 dev_err(dev->dev, "wd: write message failed\n");
 138                 return ret;
 139         }
 140
 141         ret = mei_cl_flow_ctrl_reduce(cl);
 142         if (ret) {
 143                 dev_err(dev->dev, "wd: flow_ctrl_reduce failed.\n");
 144                 return ret;
 145         }
 146
 147         return 0;
 148 }
 149
 150 /**
 151  * mei_wd_stop - sends watchdog stop message to fw.
 152  *
 153  * @dev: the device structure
 154  *
 155  * Return: 0 if success
 156  * on error:
 157  *      -EIO    when message send fails
 158  *      -EINVAL when invalid message is to be sent
 159  *      -ETIME  on message timeout
 160  */
 161 int mei_wd_stop(struct mei_device *dev)
 162 {
 163         struct mei_cl *cl = &dev->wd_cl;
 164         int ret;
 165
 166         if (!mei_cl_is_connected(cl) ||
 167             dev->wd_state != MEI_WD_RUNNING)
 168                 return 0;
 169
 170         memcpy(dev->wd_data, mei_stop_wd_params, MEI_WD_STOP_MSG_SIZE);
 171
 172         dev->wd_state = MEI_WD_STOPPING;
 173
 174         ret = mei_cl_flow_ctrl_creds(cl);
 175         if (ret < 0)
 176                 goto err;
 177
 178         if (ret && mei_hbuf_acquire(dev)) {
 179                 ret = mei_wd_send(dev);
 180                 if (ret)
 181                         goto err;
 182                 dev->wd_pending = false;
 183         } else {
 184                 dev->wd_pending = true;
 185         }
 186
 187         mutex_unlock(&dev->device_lock);
 188
 189         ret = wait_event_timeout(dev->wait_stop_wd,
 190                                 dev->wd_state == MEI_WD_IDLE,
 191                                 msecs_to_jiffies(MEI_WD_STOP_TIMEOUT));
 192         mutex_lock(&dev->device_lock);
 193         if (dev->wd_state != MEI_WD_IDLE) {
 194                 /* timeout */
 195                 ret = -ETIME;
 196                 dev_warn(dev->dev, "wd: stop failed to complete ret=%d\n", ret);
 197                 goto err;
 198         }
 199         dev_dbg(dev->dev, "wd: stop completed after %u msec\n",
 200                         MEI_WD_STOP_TIMEOUT - jiffies_to_msecs(ret));
 201         return 0;
 202 err:
 203         return ret;
 204 }
 205
 206 /**
 207  * mei_wd_ops_start - wd start command from the watchdog core.
 208  *
 209  * @wd_dev: watchdog device struct
 210  *
 211  * Return: 0 if success, negative errno code for failure
 212  */
 213 static int mei_wd_ops_start(struct watchdog_device *wd_dev)
 214 {
 215         struct mei_device *dev;
 216         struct mei_cl *cl;
 217         int err = -ENODEV;
 218
 219         dev = watchdog_get_drvdata(wd_dev);
 220         if (!dev)
 221                 return -ENODEV;
 222
 223         cl = &dev->wd_cl;
 224
 225         mutex_lock(&dev->device_lock);
 226
 227         if (dev->dev_state != MEI_DEV_ENABLED) {
 228                 dev_dbg(dev->dev, "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 (!mei_cl_is_connected(cl)) {
 234                 cl_dbg(dev, cl, "MEI Driver is not connected to Watchdog Client\n");
 235                 goto end_unlock;
 236         }
 237
 238         mei_wd_set_start_timeout(dev, dev->wd_timeout);
 239
 240         err = 0;
 241 end_unlock:
 242         mutex_unlock(&dev->device_lock);
 243         return err;
 244 }
 245
 246 /**
 247  * mei_wd_ops_stop -  wd stop command from the watchdog core.
 248  *
 249  * @wd_dev: watchdog device struct
 250  *
 251  * Return: 0 if success, negative errno code for failure
 252  */
 253 static int mei_wd_ops_stop(struct watchdog_device *wd_dev)
 254 {
 255         struct mei_device *dev;
 256
 257         dev = watchdog_get_drvdata(wd_dev);
 258         if (!dev)
 259                 return -ENODEV;
 260
 261         mutex_lock(&dev->device_lock);
 262         mei_wd_stop(dev);
 263         mutex_unlock(&dev->device_lock);
 264
 265         return 0;
 266 }
 267
 268 /**
 269  * mei_wd_ops_ping - wd ping command from the watchdog core.
 270  *
 271  * @wd_dev: watchdog device struct
 272  *
 273  * Return: 0 if success, negative errno code for failure
 274  */
 275 static int mei_wd_ops_ping(struct watchdog_device *wd_dev)
 276 {
 277         struct mei_device *dev;
 278         struct mei_cl *cl;
 279         int ret;
 280
 281         dev = watchdog_get_drvdata(wd_dev);
 282         if (!dev)
 283                 return -ENODEV;
 284
 285         cl = &dev->wd_cl;
 286
 287         mutex_lock(&dev->device_lock);
 288
 289         if (!mei_cl_is_connected(cl)) {
 290                 cl_err(dev, cl, "wd: not connected.\n");
 291                 ret = -ENODEV;
 292                 goto end;
 293         }
 294
 295         dev->wd_state = MEI_WD_RUNNING;
 296
 297         ret = mei_cl_flow_ctrl_creds(cl);
 298         if (ret < 0)
 299                 goto end;
 300
 301         /* Check if we can send the ping to HW*/
 302         if (ret && mei_hbuf_acquire(dev)) {
 303                 dev_dbg(dev->dev, "wd: sending ping\n");
 304
 305                 ret = mei_wd_send(dev);
 306                 if (ret)
 307                         goto end;
 308                 dev->wd_pending = false;
 309         } else {
 310                 dev->wd_pending = true;
 311         }
 312
 313 end:
 314         mutex_unlock(&dev->device_lock);
 315         return ret;
 316 }
 317
 318 /**
 319  * mei_wd_ops_set_timeout - wd set timeout command from the watchdog core.
 320  *
 321  * @wd_dev: watchdog device struct
 322  * @timeout: timeout value to set
 323  *
 324  * Return: 0 if success, negative errno code for failure
 325  */
 326 static int mei_wd_ops_set_timeout(struct watchdog_device *wd_dev,
 327                 unsigned int timeout)
 328 {
 329         struct mei_device *dev;
 330
 331         dev = watchdog_get_drvdata(wd_dev);
 332         if (!dev)
 333                 return -ENODEV;
 334
 335         /* Check Timeout value */
 336         if (timeout < MEI_WD_MIN_TIMEOUT || timeout > MEI_WD_MAX_TIMEOUT)
 337                 return -EINVAL;
 338
 339         mutex_lock(&dev->device_lock);
 340
 341         dev->wd_timeout = timeout;
 342         wd_dev->timeout = timeout;
 343         mei_wd_set_start_timeout(dev, dev->wd_timeout);
 344
 345         mutex_unlock(&dev->device_lock);
 346
 347         return 0;
 348 }
 349
 350 /*
 351  * Watchdog Device structs
 352  */
 353 static const struct watchdog_ops wd_ops = {
 354                 .owner = THIS_MODULE,
 355                 .start = mei_wd_ops_start,
 356                 .stop = mei_wd_ops_stop,
 357                 .ping = mei_wd_ops_ping,
 358                 .set_timeout = mei_wd_ops_set_timeout,
 359 };
 360 static const struct watchdog_info wd_info = {
 361                 .identity = INTEL_AMT_WATCHDOG_ID,
 362                 .options = WDIOF_KEEPALIVEPING |
 363                            WDIOF_SETTIMEOUT |
 364                            WDIOF_ALARMONLY,
 365 };
 366
 367 static struct watchdog_device amt_wd_dev = {
 368                 .info = &wd_info,
 369                 .ops = &wd_ops,
 370                 .timeout = MEI_WD_DEFAULT_TIMEOUT,
 371                 .min_timeout = MEI_WD_MIN_TIMEOUT,
 372                 .max_timeout = MEI_WD_MAX_TIMEOUT,
 373 };
 374
 375
 376 int mei_watchdog_register(struct mei_device *dev)
 377 {
 378
 379         int ret;
 380
 381         /* unlock to perserve correct locking order */
 382         mutex_unlock(&dev->device_lock);
 383         ret = watchdog_register_device(&amt_wd_dev);
 384         mutex_lock(&dev->device_lock);
 385         if (ret) {
 386                 dev_err(dev->dev, "wd: unable to register watchdog device = %d.\n",
 387                         ret);
 388                 return ret;
 389         }
 390
 391         dev_dbg(dev->dev, "wd: successfully register watchdog interface.\n");
 392         watchdog_set_drvdata(&amt_wd_dev, dev);
 393         return 0;
 394 }
 395
 396 void mei_watchdog_unregister(struct mei_device *dev)
 397 {
 398         if (watchdog_get_drvdata(&amt_wd_dev) == NULL)
 399                 return;
 400
 401         watchdog_set_drvdata(&amt_wd_dev, NULL);
 402         watchdog_unregister_device(&amt_wd_dev);
 403 }
 404