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  * @me_cl: me client
  54  *
  55  * Return: -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, struct mei_me_client *me_cl)
  60 {
  61         struct mei_cl *cl = &dev->wd_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         ret = mei_cl_link(cl, MEI_WD_HOST_CLIENT_ID);
  70         if (ret < 0) {
  71                 dev_info(dev->dev, "wd: failed link client\n");
  72                 return ret;
  73         }
  74
  75         ret = mei_cl_connect(cl, me_cl, NULL);
  76         if (ret) {
  77                 dev_err(dev->dev, "wd: failed to connect = %d\n", ret);
  78                 mei_cl_unlink(cl);
  79                 return ret;
  80         }
  81
  82         ret = mei_watchdog_register(dev);
  83         if (ret) {
  84                 mei_cl_disconnect(cl);
  85                 mei_cl_unlink(cl);
  86         }
  87         return ret;
  88 }
  89
  90 /**
  91  * mei_wd_send - sends watch dog message to fw.
  92  *
  93  * @dev: the device structure
  94  *
  95  * Return: 0 if success,
  96  *      -EIO when message send fails
  97  *      -EINVAL when invalid message is to be sent
  98  *      -ENODEV on flow control failure
  99  */
 100 int mei_wd_send(struct mei_device *dev)
 101 {
 102         struct mei_cl *cl = &dev->wd_cl;
 103         struct mei_msg_hdr hdr;
 104         int ret;
 105
 106         hdr.host_addr = cl->host_client_id;
 107         hdr.me_addr = mei_cl_me_id(cl);
 108         hdr.msg_complete = 1;
 109         hdr.reserved = 0;
 110         hdr.internal = 0;
 111
 112         if (!memcmp(dev->wd_data, mei_start_wd_params, MEI_WD_HDR_SIZE))
 113                 hdr.length = MEI_WD_START_MSG_SIZE;
 114         else if (!memcmp(dev->wd_data, mei_stop_wd_params, MEI_WD_HDR_SIZE))
 115                 hdr.length = MEI_WD_STOP_MSG_SIZE;
 116         else {
 117                 dev_err(dev->dev, "wd: invalid message is to be sent, aborting\n");
 118                 return -EINVAL;
 119         }
 120
 121         ret = mei_write_message(dev, &hdr, dev->wd_data);
 122         if (ret) {
 123                 dev_err(dev->dev, "wd: write message failed\n");
 124                 return ret;
 125         }
 126
 127         ret = mei_cl_flow_ctrl_reduce(cl);
 128         if (ret) {
 129                 dev_err(dev->dev, "wd: flow_ctrl_reduce failed.\n");
 130                 return ret;
 131         }
 132
 133         return 0;
 134 }
 135
 136 /**
 137  * mei_wd_stop - sends watchdog stop message to fw.
 138  *
 139  * @dev: the device structure
 140  *
 141  * Return: 0 if success
 142  * on error:
 143  *      -EIO    when message send fails
 144  *      -EINVAL when invalid message is to be sent
 145  *      -ETIME  on message timeout
 146  */
 147 int mei_wd_stop(struct mei_device *dev)
 148 {
 149         struct mei_cl *cl = &dev->wd_cl;
 150         int ret;
 151
 152         if (!mei_cl_is_connected(cl) ||
 153             dev->wd_state != MEI_WD_RUNNING)
 154                 return 0;
 155
 156         memcpy(dev->wd_data, mei_stop_wd_params, MEI_WD_STOP_MSG_SIZE);
 157
 158         dev->wd_state = MEI_WD_STOPPING;
 159
 160         ret = mei_cl_flow_ctrl_creds(cl);
 161         if (ret < 0)
 162                 goto err;
 163
 164         if (ret && mei_hbuf_acquire(dev)) {
 165                 ret = mei_wd_send(dev);
 166                 if (ret)
 167                         goto err;
 168                 dev->wd_pending = false;
 169         } else {
 170                 dev->wd_pending = true;
 171         }
 172
 173         mutex_unlock(&dev->device_lock);
 174
 175         ret = wait_event_timeout(dev->wait_stop_wd,
 176                                 dev->wd_state == MEI_WD_IDLE,
 177                                 msecs_to_jiffies(MEI_WD_STOP_TIMEOUT));
 178         mutex_lock(&dev->device_lock);
 179         if (dev->wd_state != MEI_WD_IDLE) {
 180                 /* timeout */
 181                 ret = -ETIME;
 182                 dev_warn(dev->dev, "wd: stop failed to complete ret=%d\n", ret);
 183                 goto err;
 184         }
 185         dev_dbg(dev->dev, "wd: stop completed after %u msec\n",
 186                         MEI_WD_STOP_TIMEOUT - jiffies_to_msecs(ret));
 187         return 0;
 188 err:
 189         return ret;
 190 }
 191
 192 /**
 193  * mei_wd_ops_start - wd start command from the watchdog core.
 194  *
 195  * @wd_dev: watchdog device struct
 196  *
 197  * Return: 0 if success, negative errno code for failure
 198  */
 199 static int mei_wd_ops_start(struct watchdog_device *wd_dev)
 200 {
 201         struct mei_device *dev;
 202         struct mei_cl *cl;
 203         int err = -ENODEV;
 204
 205         dev = watchdog_get_drvdata(wd_dev);
 206         if (!dev)
 207                 return -ENODEV;
 208
 209         cl = &dev->wd_cl;
 210
 211         mutex_lock(&dev->device_lock);
 212
 213         if (dev->dev_state != MEI_DEV_ENABLED) {
 214                 dev_dbg(dev->dev, "wd: dev_state != MEI_DEV_ENABLED  dev_state = %s\n",
 215                         mei_dev_state_str(dev->dev_state));
 216                 goto end_unlock;
 217         }
 218
 219         if (!mei_cl_is_connected(cl)) {
 220                 cl_dbg(dev, cl, "MEI Driver is not connected to Watchdog Client\n");
 221                 goto end_unlock;
 222         }
 223
 224         mei_wd_set_start_timeout(dev, dev->wd_timeout);
 225
 226         err = 0;
 227 end_unlock:
 228         mutex_unlock(&dev->device_lock);
 229         return err;
 230 }
 231
 232 /**
 233  * mei_wd_ops_stop -  wd stop command from the watchdog core.
 234  *
 235  * @wd_dev: watchdog device struct
 236  *
 237  * Return: 0 if success, negative errno code for failure
 238  */
 239 static int mei_wd_ops_stop(struct watchdog_device *wd_dev)
 240 {
 241         struct mei_device *dev;
 242
 243         dev = watchdog_get_drvdata(wd_dev);
 244         if (!dev)
 245                 return -ENODEV;
 246
 247         mutex_lock(&dev->device_lock);
 248         mei_wd_stop(dev);
 249         mutex_unlock(&dev->device_lock);
 250
 251         return 0;
 252 }
 253
 254 /**
 255  * mei_wd_ops_ping - wd ping command from the watchdog core.
 256  *
 257  * @wd_dev: watchdog device struct
 258  *
 259  * Return: 0 if success, negative errno code for failure
 260  */
 261 static int mei_wd_ops_ping(struct watchdog_device *wd_dev)
 262 {
 263         struct mei_device *dev;
 264         struct mei_cl *cl;
 265         int ret;
 266
 267         dev = watchdog_get_drvdata(wd_dev);
 268         if (!dev)
 269                 return -ENODEV;
 270
 271         cl = &dev->wd_cl;
 272
 273         mutex_lock(&dev->device_lock);
 274
 275         if (!mei_cl_is_connected(cl)) {
 276                 cl_err(dev, cl, "wd: not connected.\n");
 277                 ret = -ENODEV;
 278                 goto end;
 279         }
 280
 281         dev->wd_state = MEI_WD_RUNNING;
 282
 283         ret = mei_cl_flow_ctrl_creds(cl);
 284         if (ret < 0)
 285                 goto end;
 286
 287         /* Check if we can send the ping to HW*/
 288         if (ret && mei_hbuf_acquire(dev)) {
 289                 dev_dbg(dev->dev, "wd: sending ping\n");
 290
 291                 ret = mei_wd_send(dev);
 292                 if (ret)
 293                         goto end;
 294                 dev->wd_pending = false;
 295         } else {
 296                 dev->wd_pending = true;
 297         }
 298
 299 end:
 300         mutex_unlock(&dev->device_lock);
 301         return ret;
 302 }
 303
 304 /**
 305  * mei_wd_ops_set_timeout - wd set timeout command from the watchdog core.
 306  *
 307  * @wd_dev: watchdog device struct
 308  * @timeout: timeout value to set
 309  *
 310  * Return: 0 if success, negative errno code for failure
 311  */
 312 static int mei_wd_ops_set_timeout(struct watchdog_device *wd_dev,
 313                 unsigned int timeout)
 314 {
 315         struct mei_device *dev;
 316
 317         dev = watchdog_get_drvdata(wd_dev);
 318         if (!dev)
 319                 return -ENODEV;
 320
 321         /* Check Timeout value */
 322         if (timeout < MEI_WD_MIN_TIMEOUT || timeout > MEI_WD_MAX_TIMEOUT)
 323                 return -EINVAL;
 324
 325         mutex_lock(&dev->device_lock);
 326
 327         dev->wd_timeout = timeout;
 328         wd_dev->timeout = timeout;
 329         mei_wd_set_start_timeout(dev, dev->wd_timeout);
 330
 331         mutex_unlock(&dev->device_lock);
 332
 333         return 0;
 334 }
 335
 336 /*
 337  * Watchdog Device structs
 338  */
 339 static const struct watchdog_ops wd_ops = {
 340                 .owner = THIS_MODULE,
 341                 .start = mei_wd_ops_start,
 342                 .stop = mei_wd_ops_stop,
 343                 .ping = mei_wd_ops_ping,
 344                 .set_timeout = mei_wd_ops_set_timeout,
 345 };
 346 static const struct watchdog_info wd_info = {
 347                 .identity = INTEL_AMT_WATCHDOG_ID,
 348                 .options = WDIOF_KEEPALIVEPING |
 349                            WDIOF_SETTIMEOUT |
 350                            WDIOF_ALARMONLY,
 351 };
 352
 353 static struct watchdog_device amt_wd_dev = {
 354                 .info = &wd_info,
 355                 .ops = &wd_ops,
 356                 .timeout = MEI_WD_DEFAULT_TIMEOUT,
 357                 .min_timeout = MEI_WD_MIN_TIMEOUT,
 358                 .max_timeout = MEI_WD_MAX_TIMEOUT,
 359 };
 360
 361
 362 int mei_watchdog_register(struct mei_device *dev)
 363 {
 364
 365         int ret;
 366
 367         /* unlock to perserve correct locking order */
 368         mutex_unlock(&dev->device_lock);
 369         ret = watchdog_register_device(&amt_wd_dev);
 370         mutex_lock(&dev->device_lock);
 371         if (ret) {
 372                 dev_err(dev->dev, "wd: unable to register watchdog device = %d.\n",
 373                         ret);
 374                 return ret;
 375         }
 376
 377         dev_dbg(dev->dev, "wd: successfully register watchdog interface.\n");
 378         watchdog_set_drvdata(&amt_wd_dev, dev);
 379         return 0;
 380 }
 381
 382 void mei_watchdog_unregister(struct mei_device *dev)
 383 {
 384         if (watchdog_get_drvdata(&amt_wd_dev) == NULL)
 385                 return;
 386
 387         watchdog_set_drvdata(&amt_wd_dev, NULL);
 388         watchdog_unregister_device(&amt_wd_dev);
 389 }
 390