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