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
  80         ret = mei_cl_link(cl, MEI_WD_HOST_CLIENT_ID);
  81
  82         if (ret < 0) {
  83                 dev_info(dev->dev, "wd: failed link client\n");
  84                 return ret;
  85         }
  86
  87         ret = mei_cl_connect(cl, NULL);
  88
  89         if (ret) {
  90                 dev_err(dev->dev, "wd: failed to connect = %d\n", ret);
  91                 mei_cl_unlink(cl);
  92                 return ret;
  93         }
  94
  95         ret = mei_watchdog_register(dev);
  96         if (ret) {
  97                 mei_cl_disconnect(cl);
  98                 mei_cl_unlink(cl);
  99         }
 100         return ret;
 101 }
 102
 103 /**
 104  * mei_wd_send - sends watch dog message to fw.
 105  *
 106  * @dev: the device structure
 107  *
 108  * Return: 0 if success,
 109  *      -EIO when message send fails
 110  *      -EINVAL when invalid message is to be sent
 111  *      -ENODEV on flow control failure
 112  */
 113 int mei_wd_send(struct mei_device *dev)
 114 {
 115         struct mei_cl *cl = &dev->wd_cl;
 116         struct mei_msg_hdr hdr;
 117         int ret;
 118
 119         hdr.host_addr = cl->host_client_id;
 120         hdr.me_addr = cl->me_client_id;
 121         hdr.msg_complete = 1;
 122         hdr.reserved = 0;
 123         hdr.internal = 0;
 124
 125         if (!memcmp(dev->wd_data, mei_start_wd_params, MEI_WD_HDR_SIZE))
 126                 hdr.length = MEI_WD_START_MSG_SIZE;
 127         else if (!memcmp(dev->wd_data, mei_stop_wd_params, MEI_WD_HDR_SIZE))
 128                 hdr.length = MEI_WD_STOP_MSG_SIZE;
 129         else {
 130                 dev_err(dev->dev, "wd: invalid message is to be sent, aborting\n");
 131                 return -EINVAL;
 132         }
 133
 134         ret = mei_write_message(dev, &hdr, dev->wd_data);
 135         if (ret) {
 136                 dev_err(dev->dev, "wd: write message failed\n");
 137                 return ret;
 138         }
 139
 140         ret = mei_cl_flow_ctrl_reduce(cl);
 141         if (ret) {
 142                 dev_err(dev->dev, "wd: flow_ctrl_reduce failed.\n");
 143                 return ret;
 144         }
 145
 146         return 0;
 147 }
 148
 149 /**
 150  * mei_wd_stop - sends watchdog stop message to fw.
 151  *
 152  * @dev: the device structure
 153  *
 154  * Return: 0 if success
 155  * on error:
 156  *      -EIO    when message send fails
 157  *      -EINVAL when invalid message is to be sent
 158  *      -ETIME  on message timeout
 159  */
 160 int mei_wd_stop(struct mei_device *dev)
 161 {
 162         int ret;
 163
 164         if (dev->wd_cl.state != MEI_FILE_CONNECTED ||
 165             dev->wd_state != MEI_WD_RUNNING)
 166                 return 0;
 167
 168         memcpy(dev->wd_data, mei_stop_wd_params, MEI_WD_STOP_MSG_SIZE);
 169
 170         dev->wd_state = MEI_WD_STOPPING;
 171
 172         ret = mei_cl_flow_ctrl_creds(&dev->wd_cl);
 173         if (ret < 0)
 174                 goto err;
 175
 176         if (ret && mei_hbuf_acquire(dev)) {
 177                 ret = mei_wd_send(dev);
 178                 if (ret)
 179                         goto err;
 180                 dev->wd_pending = false;
 181         } else {
 182                 dev->wd_pending = true;
 183         }
 184
 185         mutex_unlock(&dev->device_lock);
 186
 187         ret = wait_event_timeout(dev->wait_stop_wd,
 188                                 dev->wd_state == MEI_WD_IDLE,
 189                                 msecs_to_jiffies(MEI_WD_STOP_TIMEOUT));
 190         mutex_lock(&dev->device_lock);
 191         if (dev->wd_state != MEI_WD_IDLE) {
 192                 /* timeout */
 193                 ret = -ETIME;
 194                 dev_warn(dev->dev, "wd: stop failed to complete ret=%d\n", ret);
 195                 goto err;
 196         }
 197         dev_dbg(dev->dev, "wd: stop completed after %u msec\n",
 198                         MEI_WD_STOP_TIMEOUT - jiffies_to_msecs(ret));
 199         return 0;
 200 err:
 201         return ret;
 202 }
 203
 204 /*
 205  * mei_wd_ops_start - wd start command from the watchdog core.
 206  *
 207  * @wd_dev - watchdog device struct
 208  *
 209  * Return: 0 if success, negative errno code for failure
 210  */
 211 static int mei_wd_ops_start(struct watchdog_device *wd_dev)
 212 {
 213         int err = -ENODEV;
 214         struct mei_device *dev;
 215
 216         dev = watchdog_get_drvdata(wd_dev);
 217         if (!dev)
 218                 return -ENODEV;
 219
 220         mutex_lock(&dev->device_lock);
 221
 222         if (dev->dev_state != MEI_DEV_ENABLED) {
 223                 dev_dbg(dev->dev, "wd: dev_state != MEI_DEV_ENABLED  dev_state = %s\n",
 224                         mei_dev_state_str(dev->dev_state));
 225                 goto end_unlock;
 226         }
 227
 228         if (dev->wd_cl.state != MEI_FILE_CONNECTED)     {
 229                 dev_dbg(dev->dev, "MEI Driver is not connected to Watchdog Client\n");
 230                 goto end_unlock;
 231         }
 232
 233         mei_wd_set_start_timeout(dev, dev->wd_timeout);
 234
 235         err = 0;
 236 end_unlock:
 237         mutex_unlock(&dev->device_lock);
 238         return err;
 239 }
 240
 241 /*
 242  * mei_wd_ops_stop -  wd stop command from the watchdog core.
 243  *
 244  * @wd_dev - watchdog device struct
 245  *
 246  * Return: 0 if success, negative errno code for failure
 247  */
 248 static int mei_wd_ops_stop(struct watchdog_device *wd_dev)
 249 {
 250         struct mei_device *dev;
 251
 252         dev = watchdog_get_drvdata(wd_dev);
 253         if (!dev)
 254                 return -ENODEV;
 255
 256         mutex_lock(&dev->device_lock);
 257         mei_wd_stop(dev);
 258         mutex_unlock(&dev->device_lock);
 259
 260         return 0;
 261 }
 262
 263 /*
 264  * mei_wd_ops_ping - wd ping command from the watchdog core.
 265  *
 266  * @wd_dev - watchdog device struct
 267  *
 268  * Return: 0 if success, negative errno code for failure
 269  */
 270 static int mei_wd_ops_ping(struct watchdog_device *wd_dev)
 271 {
 272         struct mei_device *dev;
 273         int ret;
 274
 275         dev = watchdog_get_drvdata(wd_dev);
 276         if (!dev)
 277                 return -ENODEV;
 278
 279         mutex_lock(&dev->device_lock);
 280
 281         if (dev->wd_cl.state != MEI_FILE_CONNECTED) {
 282                 dev_err(dev->dev, "wd: not connected.\n");
 283                 ret = -ENODEV;
 284                 goto end;
 285         }
 286
 287         dev->wd_state = MEI_WD_RUNNING;
 288
 289         ret = mei_cl_flow_ctrl_creds(&dev->wd_cl);
 290         if (ret < 0)
 291                 goto end;
 292         /* Check if we can send the ping to HW*/
 293         if (ret && mei_hbuf_acquire(dev)) {
 294
 295                 dev_dbg(dev->dev, "wd: sending ping\n");
 296
 297                 ret = mei_wd_send(dev);
 298                 if (ret)
 299                         goto end;
 300                 dev->wd_pending = false;
 301         } else {
 302                 dev->wd_pending = true;
 303         }
 304
 305 end:
 306         mutex_unlock(&dev->device_lock);
 307         return ret;
 308 }
 309
 310 /*
 311  * mei_wd_ops_set_timeout - wd set timeout command from the watchdog core.
 312  *
 313  * @wd_dev - watchdog device struct
 314  * @timeout - timeout value to set
 315  *
 316  * Return: 0 if success, negative errno code for failure
 317  */
 318 static int mei_wd_ops_set_timeout(struct watchdog_device *wd_dev,
 319                 unsigned int timeout)
 320 {
 321         struct mei_device *dev;
 322
 323         dev = watchdog_get_drvdata(wd_dev);
 324         if (!dev)
 325                 return -ENODEV;
 326
 327         /* Check Timeout value */
 328         if (timeout < MEI_WD_MIN_TIMEOUT || timeout > MEI_WD_MAX_TIMEOUT)
 329                 return -EINVAL;
 330
 331         mutex_lock(&dev->device_lock);
 332
 333         dev->wd_timeout = timeout;
 334         wd_dev->timeout = timeout;
 335         mei_wd_set_start_timeout(dev, dev->wd_timeout);
 336
 337         mutex_unlock(&dev->device_lock);
 338
 339         return 0;
 340 }
 341
 342 /*
 343  * Watchdog Device structs
 344  */
 345 static const struct watchdog_ops wd_ops = {
 346                 .owner = THIS_MODULE,
 347                 .start = mei_wd_ops_start,
 348                 .stop = mei_wd_ops_stop,
 349                 .ping = mei_wd_ops_ping,
 350                 .set_timeout = mei_wd_ops_set_timeout,
 351 };
 352 static const struct watchdog_info wd_info = {
 353                 .identity = INTEL_AMT_WATCHDOG_ID,
 354                 .options = WDIOF_KEEPALIVEPING |
 355                            WDIOF_SETTIMEOUT |
 356                            WDIOF_ALARMONLY,
 357 };
 358
 359 static struct watchdog_device amt_wd_dev = {
 360                 .info = &wd_info,
 361                 .ops = &wd_ops,
 362                 .timeout = MEI_WD_DEFAULT_TIMEOUT,
 363                 .min_timeout = MEI_WD_MIN_TIMEOUT,
 364                 .max_timeout = MEI_WD_MAX_TIMEOUT,
 365 };
 366
 367
 368 int mei_watchdog_register(struct mei_device *dev)
 369 {
 370
 371         int ret;
 372
 373         /* unlock to perserve correct locking order */
 374         mutex_unlock(&dev->device_lock);
 375         ret = watchdog_register_device(&amt_wd_dev);
 376         mutex_lock(&dev->device_lock);
 377         if (ret) {
 378                 dev_err(dev->dev, "wd: unable to register watchdog device = %d.\n",
 379                         ret);
 380                 return ret;
 381         }
 382
 383         dev_dbg(dev->dev, "wd: successfully register watchdog interface.\n");
 384         watchdog_set_drvdata(&amt_wd_dev, dev);
 385         return 0;
 386 }
 387
 388 void mei_watchdog_unregister(struct mei_device *dev)
 389 {
 390         if (watchdog_get_drvdata(&amt_wd_dev) == NULL)
 391                 return;
 392
 393         watchdog_set_drvdata(&amt_wd_dev, NULL);
 394         watchdog_unregister_device(&amt_wd_dev);
 395 }
 396