drivers/mfd/cros_ec_dev.c

   1 /*
   2  * cros_ec_dev - expose the Chrome OS Embedded Controller to user-space
   3  *
   4  * Copyright (C) 2014 Google, Inc.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <linux/fs.h>
  21 #include <linux/mfd/core.h>
  22 #include <linux/module.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/pm.h>
  25 #include <linux/slab.h>
  26 #include <linux/uaccess.h>
  27
  28 #include "cros_ec_dev.h"
  29
  30 #define DRV_NAME "cros-ec-dev"
  31
  32 /* Device variables */
  33 #define CROS_MAX_DEV 128
  34 static int ec_major;
  35
  36 static const struct attribute_group *cros_ec_groups[] = {
  37         &cros_ec_attr_group,
  38         &cros_ec_lightbar_attr_group,
  39         &cros_ec_vbc_attr_group,
  40         NULL,
  41 };
  42
  43 static struct class cros_class = {
  44         .owner          = THIS_MODULE,
  45         .name           = "chromeos",
  46         .dev_groups     = cros_ec_groups,
  47 };
  48
  49 /* Basic communication */
  50 static int ec_get_version(struct cros_ec_dev *ec, char *str, int maxlen)
  51 {
  52         struct ec_response_get_version *resp;
  53         static const char * const current_image_name[] = {
  54                 "unknown", "read-only", "read-write", "invalid",
  55         };
  56         struct cros_ec_command *msg;
  57         int ret;
  58
  59         msg = kmalloc(sizeof(*msg) + sizeof(*resp), GFP_KERNEL);
  60         if (!msg)
  61                 return -ENOMEM;
  62
  63         msg->version = 0;
  64         msg->command = EC_CMD_GET_VERSION + ec->cmd_offset;
  65         msg->insize = sizeof(*resp);
  66         msg->outsize = 0;
  67
  68         ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
  69         if (ret < 0)
  70                 goto exit;
  71
  72         if (msg->result != EC_RES_SUCCESS) {
  73                 snprintf(str, maxlen,
  74                          "%s\nUnknown EC version: EC returned %d\n",
  75                          CROS_EC_DEV_VERSION, msg->result);
  76                 ret = -EINVAL;
  77                 goto exit;
  78         }
  79
  80         resp = (struct ec_response_get_version *)msg->data;
  81         if (resp->current_image >= ARRAY_SIZE(current_image_name))
  82                 resp->current_image = 3; /* invalid */
  83
  84         snprintf(str, maxlen, "%s\n%s\n%s\n%s\n", CROS_EC_DEV_VERSION,
  85                  resp->version_string_ro, resp->version_string_rw,
  86                  current_image_name[resp->current_image]);
  87
  88         ret = 0;
  89 exit:
  90         kfree(msg);
  91         return ret;
  92 }
  93
  94 static int cros_ec_check_features(struct cros_ec_dev *ec, int feature)
  95 {
  96         struct cros_ec_command *msg;
  97         int ret;
  98
  99         if (ec->features[0] == -1U && ec->features[1] == -1U) {
 100                 /* features bitmap not read yet */
 101
 102                 msg = kmalloc(sizeof(*msg) + sizeof(ec->features), GFP_KERNEL);
 103                 if (!msg)
 104                         return -ENOMEM;
 105
 106                 msg->version = 0;
 107                 msg->command = EC_CMD_GET_FEATURES + ec->cmd_offset;
 108                 msg->insize = sizeof(ec->features);
 109                 msg->outsize = 0;
 110
 111                 ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
 112                 if (ret < 0 || msg->result != EC_RES_SUCCESS) {
 113                         dev_warn(ec->dev, "cannot get EC features: %d/%d\n",
 114                                  ret, msg->result);
 115                         memset(ec->features, 0, sizeof(ec->features));
 116                 }
 117
 118                 memcpy(ec->features, msg->data, sizeof(ec->features));
 119
 120                 dev_dbg(ec->dev, "EC features %08x %08x\n",
 121                         ec->features[0], ec->features[1]);
 122
 123                 kfree(msg);
 124         }
 125
 126         return ec->features[feature / 32] & EC_FEATURE_MASK_0(feature);
 127 }
 128
 129 /* Device file ops */
 130 static int ec_device_open(struct inode *inode, struct file *filp)
 131 {
 132         struct cros_ec_dev *ec = container_of(inode->i_cdev,
 133                                               struct cros_ec_dev, cdev);
 134         filp->private_data = ec;
 135         nonseekable_open(inode, filp);
 136         return 0;
 137 }
 138
 139 static int ec_device_release(struct inode *inode, struct file *filp)
 140 {
 141         return 0;
 142 }
 143
 144 static ssize_t ec_device_read(struct file *filp, char __user *buffer,
 145                               size_t length, loff_t *offset)
 146 {
 147         struct cros_ec_dev *ec = filp->private_data;
 148         char msg[sizeof(struct ec_response_get_version) +
 149                  sizeof(CROS_EC_DEV_VERSION)];
 150         size_t count;
 151         int ret;
 152
 153         if (*offset != 0)
 154                 return 0;
 155
 156         ret = ec_get_version(ec, msg, sizeof(msg));
 157         if (ret)
 158                 return ret;
 159
 160         count = min(length, strlen(msg));
 161
 162         if (copy_to_user(buffer, msg, count))
 163                 return -EFAULT;
 164
 165         *offset = count;
 166         return count;
 167 }
 168
 169 /* Ioctls */
 170 static long ec_device_ioctl_xcmd(struct cros_ec_dev *ec, void __user *arg)
 171 {
 172         long ret;
 173         struct cros_ec_command u_cmd;
 174         struct cros_ec_command *s_cmd;
 175
 176         if (copy_from_user(&u_cmd, arg, sizeof(u_cmd)))
 177                 return -EFAULT;
 178
 179         if ((u_cmd.outsize > EC_MAX_MSG_BYTES) ||
 180             (u_cmd.insize > EC_MAX_MSG_BYTES))
 181                 return -EINVAL;
 182
 183         s_cmd = kmalloc(sizeof(*s_cmd) + max(u_cmd.outsize, u_cmd.insize),
 184                         GFP_KERNEL);
 185         if (!s_cmd)
 186                 return -ENOMEM;
 187
 188         if (copy_from_user(s_cmd, arg, sizeof(*s_cmd) + u_cmd.outsize)) {
 189                 ret = -EFAULT;
 190                 goto exit;
 191         }
 192
 193         if (u_cmd.outsize != s_cmd->outsize ||
 194             u_cmd.insize != s_cmd->insize) {
 195                 ret = -EINVAL;
 196                 goto exit;
 197         }
 198
 199         s_cmd->command += ec->cmd_offset;
 200         ret = cros_ec_cmd_xfer(ec->ec_dev, s_cmd);
 201         /* Only copy data to userland if data was received. */
 202         if (ret < 0)
 203                 goto exit;
 204
 205         if (copy_to_user(arg, s_cmd, sizeof(*s_cmd) + s_cmd->insize))
 206                 ret = -EFAULT;
 207 exit:
 208         kfree(s_cmd);
 209         return ret;
 210 }
 211
 212 static long ec_device_ioctl_readmem(struct cros_ec_dev *ec, void __user *arg)
 213 {
 214         struct cros_ec_device *ec_dev = ec->ec_dev;
 215         struct cros_ec_readmem s_mem = { };
 216         long num;
 217
 218         /* Not every platform supports direct reads */
 219         if (!ec_dev->cmd_readmem)
 220                 return -ENOTTY;
 221
 222         if (copy_from_user(&s_mem, arg, sizeof(s_mem)))
 223                 return -EFAULT;
 224
 225         num = ec_dev->cmd_readmem(ec_dev, s_mem.offset, s_mem.bytes,
 226                                   s_mem.buffer);
 227         if (num <= 0)
 228                 return num;
 229
 230         if (copy_to_user((void __user *)arg, &s_mem, sizeof(s_mem)))
 231                 return -EFAULT;
 232
 233         return 0;
 234 }
 235
 236 static long ec_device_ioctl(struct file *filp, unsigned int cmd,
 237                             unsigned long arg)
 238 {
 239         struct cros_ec_dev *ec = filp->private_data;
 240
 241         if (_IOC_TYPE(cmd) != CROS_EC_DEV_IOC)
 242                 return -ENOTTY;
 243
 244         switch (cmd) {
 245         case CROS_EC_DEV_IOCXCMD:
 246                 return ec_device_ioctl_xcmd(ec, (void __user *)arg);
 247         case CROS_EC_DEV_IOCRDMEM:
 248                 return ec_device_ioctl_readmem(ec, (void __user *)arg);
 249         }
 250
 251         return -ENOTTY;
 252 }
 253
 254 /* Module initialization */
 255 static const struct file_operations fops = {
 256         .open = ec_device_open,
 257         .release = ec_device_release,
 258         .read = ec_device_read,
 259         .unlocked_ioctl = ec_device_ioctl,
 260 #ifdef CONFIG_COMPAT
 261         .compat_ioctl = ec_device_ioctl,
 262 #endif
 263 };
 264
 265 static void __remove(struct device *dev)
 266 {
 267         struct cros_ec_dev *ec = container_of(dev, struct cros_ec_dev,
 268                                               class_dev);
 269         kfree(ec);
 270 }
 271
 272 static void cros_ec_sensors_register(struct cros_ec_dev *ec)
 273 {
 274         /*
 275          * Issue a command to get the number of sensor reported.
 276          * Build an array of sensors driver and register them all.
 277          */
 278         int ret, i, id, sensor_num;
 279         struct mfd_cell *sensor_cells;
 280         struct cros_ec_sensor_platform *sensor_platforms;
 281         int sensor_type[MOTIONSENSE_TYPE_MAX];
 282         struct ec_params_motion_sense *params;
 283         struct ec_response_motion_sense *resp;
 284         struct cros_ec_command *msg;
 285
 286         msg = kzalloc(sizeof(struct cros_ec_command) +
 287                       max(sizeof(*params), sizeof(*resp)), GFP_KERNEL);
 288         if (msg == NULL)
 289                 return;
 290
 291         msg->version = 2;
 292         msg->command = EC_CMD_MOTION_SENSE_CMD + ec->cmd_offset;
 293         msg->outsize = sizeof(*params);
 294         msg->insize = sizeof(*resp);
 295
 296         params = (struct ec_params_motion_sense *)msg->data;
 297         params->cmd = MOTIONSENSE_CMD_DUMP;
 298
 299         ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
 300         if (ret < 0 || msg->result != EC_RES_SUCCESS) {
 301                 dev_warn(ec->dev, "cannot get EC sensor information: %d/%d\n",
 302                          ret, msg->result);
 303                 goto error;
 304         }
 305
 306         resp = (struct ec_response_motion_sense *)msg->data;
 307         sensor_num = resp->dump.sensor_count;
 308         /* Allocate 2 extra sensors in case lid angle or FIFO are needed */
 309         sensor_cells = kzalloc(sizeof(struct mfd_cell) * (sensor_num + 2),
 310                                GFP_KERNEL);
 311         if (sensor_cells == NULL)
 312                 goto error;
 313
 314         sensor_platforms = kzalloc(sizeof(struct cros_ec_sensor_platform) *
 315                   (sensor_num + 1), GFP_KERNEL);
 316         if (sensor_platforms == NULL)
 317                 goto error_platforms;
 318
 319         memset(sensor_type, 0, sizeof(sensor_type));
 320         id = 0;
 321         for (i = 0; i < sensor_num; i++) {
 322                 params->cmd = MOTIONSENSE_CMD_INFO;
 323                 params->info.sensor_num = i;
 324                 ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
 325                 if (ret < 0 || msg->result != EC_RES_SUCCESS) {
 326                         dev_warn(ec->dev, "no info for EC sensor %d : %d/%d\n",
 327                                  i, ret, msg->result);
 328                         continue;
 329                 }
 330                 switch (resp->info.type) {
 331                 case MOTIONSENSE_TYPE_ACCEL:
 332                         sensor_cells[id].name = "cros-ec-accel";
 333                         break;
 334                 case MOTIONSENSE_TYPE_BARO:
 335                         sensor_cells[id].name = "cros-ec-baro";
 336                         break;
 337                 case MOTIONSENSE_TYPE_GYRO:
 338                         sensor_cells[id].name = "cros-ec-gyro";
 339                         break;
 340                 case MOTIONSENSE_TYPE_MAG:
 341                         sensor_cells[id].name = "cros-ec-mag";
 342                         break;
 343                 case MOTIONSENSE_TYPE_PROX:
 344                         sensor_cells[id].name = "cros-ec-prox";
 345                         break;
 346                 case MOTIONSENSE_TYPE_LIGHT:
 347                         sensor_cells[id].name = "cros-ec-light";
 348                         break;
 349                 case MOTIONSENSE_TYPE_ACTIVITY:
 350                         sensor_cells[id].name = "cros-ec-activity";
 351                         break;
 352                 default:
 353                         dev_warn(ec->dev, "unknown type %d\n", resp->info.type);
 354                         continue;
 355                 }
 356                 sensor_platforms[id].sensor_num = i;
 357                 sensor_cells[id].id = sensor_type[resp->info.type];
 358                 sensor_cells[id].platform_data = &sensor_platforms[id];
 359                 sensor_cells[id].pdata_size =
 360                         sizeof(struct cros_ec_sensor_platform);
 361
 362                 sensor_type[resp->info.type]++;
 363                 id++;
 364         }
 365         if (sensor_type[MOTIONSENSE_TYPE_ACCEL] >= 2) {
 366                 sensor_platforms[id].sensor_num = sensor_num;
 367
 368                 sensor_cells[id].name = "cros-ec-angle";
 369                 sensor_cells[id].id = 0;
 370                 sensor_cells[id].platform_data = &sensor_platforms[id];
 371                 sensor_cells[id].pdata_size =
 372                         sizeof(struct cros_ec_sensor_platform);
 373                 id++;
 374         }
 375         if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE_FIFO)) {
 376                 sensor_cells[id].name = "cros-ec-ring";
 377                 id++;
 378         }
 379
 380         ret = mfd_add_devices(ec->dev, 0, sensor_cells, id,
 381                               NULL, 0, NULL);
 382         if (ret)
 383                 dev_err(ec->dev, "failed to add EC sensors\n");
 384
 385         kfree(sensor_platforms);
 386 error_platforms:
 387         kfree(sensor_cells);
 388 error:
 389         kfree(msg);
 390 }
 391
 392 static int ec_device_probe(struct platform_device *pdev)
 393 {
 394         int retval = -ENOMEM;
 395         struct device *dev = &pdev->dev;
 396         struct cros_ec_platform *ec_platform = dev_get_platdata(dev);
 397         struct cros_ec_dev *ec = kzalloc(sizeof(*ec), GFP_KERNEL);
 398
 399         if (!ec)
 400                 return retval;
 401
 402         dev_set_drvdata(dev, ec);
 403         ec->ec_dev = dev_get_drvdata(dev->parent);
 404         ec->dev = dev;
 405         ec->cmd_offset = ec_platform->cmd_offset;
 406         ec->features[0] = -1U; /* Not cached yet */
 407         ec->features[1] = -1U; /* Not cached yet */
 408         device_initialize(&ec->class_dev);
 409         cdev_init(&ec->cdev, &fops);
 410
 411         /*
 412          * Add the class device
 413          * Link to the character device for creating the /dev entry
 414          * in devtmpfs.
 415          */
 416         ec->class_dev.devt = MKDEV(ec_major, pdev->id);
 417         ec->class_dev.class = &cros_class;
 418         ec->class_dev.parent = dev;
 419         ec->class_dev.release = __remove;
 420
 421         retval = dev_set_name(&ec->class_dev, "%s", ec_platform->ec_name);
 422         if (retval) {
 423                 dev_err(dev, "dev_set_name failed => %d\n", retval);
 424                 goto failed;
 425         }
 426
 427         retval = cdev_device_add(&ec->cdev, &ec->class_dev);
 428         if (retval) {
 429                 dev_err(dev, "cdev_device_add failed => %d\n", retval);
 430                 goto failed;
 431         }
 432
 433         if (cros_ec_debugfs_init(ec))
 434                 dev_warn(dev, "failed to create debugfs directory\n");
 435
 436         /* check whether this EC is a sensor hub. */
 437         if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE))
 438                 cros_ec_sensors_register(ec);
 439
 440         /* Take control of the lightbar from the EC. */
 441         lb_manual_suspend_ctrl(ec, 1);
 442
 443         return 0;
 444
 445 failed:
 446         put_device(&ec->class_dev);
 447         return retval;
 448 }
 449
 450 static int ec_device_remove(struct platform_device *pdev)
 451 {
 452         struct cros_ec_dev *ec = dev_get_drvdata(&pdev->dev);
 453
 454         /* Let the EC take over the lightbar again. */
 455         lb_manual_suspend_ctrl(ec, 0);
 456
 457         cros_ec_debugfs_remove(ec);
 458
 459         cdev_del(&ec->cdev);
 460         device_unregister(&ec->class_dev);
 461         return 0;
 462 }
 463
 464 static const struct platform_device_id cros_ec_id[] = {
 465         { DRV_NAME, 0 },
 466         { /* sentinel */ },
 467 };
 468 MODULE_DEVICE_TABLE(platform, cros_ec_id);
 469
 470 static __maybe_unused int ec_device_suspend(struct device *dev)
 471 {
 472         struct cros_ec_dev *ec = dev_get_drvdata(dev);
 473
 474         lb_suspend(ec);
 475
 476         return 0;
 477 }
 478
 479 static __maybe_unused int ec_device_resume(struct device *dev)
 480 {
 481         struct cros_ec_dev *ec = dev_get_drvdata(dev);
 482
 483         lb_resume(ec);
 484
 485         return 0;
 486 }
 487
 488 static const struct dev_pm_ops cros_ec_dev_pm_ops = {
 489 #ifdef CONFIG_PM_SLEEP
 490         .suspend = ec_device_suspend,
 491         .resume = ec_device_resume,
 492 #endif
 493 };
 494
 495 static struct platform_driver cros_ec_dev_driver = {
 496         .driver = {
 497                 .name = DRV_NAME,
 498                 .pm = &cros_ec_dev_pm_ops,
 499         },
 500         .probe = ec_device_probe,
 501         .remove = ec_device_remove,
 502 };
 503
 504 static int __init cros_ec_dev_init(void)
 505 {
 506         int ret;
 507         dev_t dev = 0;
 508
 509         ret  = class_register(&cros_class);
 510         if (ret) {
 511                 pr_err(CROS_EC_DEV_NAME ": failed to register device class\n");
 512                 return ret;
 513         }
 514
 515         /* Get a range of minor numbers (starting with 0) to work with */
 516         ret = alloc_chrdev_region(&dev, 0, CROS_MAX_DEV, CROS_EC_DEV_NAME);
 517         if (ret < 0) {
 518                 pr_err(CROS_EC_DEV_NAME ": alloc_chrdev_region() failed\n");
 519                 goto failed_chrdevreg;
 520         }
 521         ec_major = MAJOR(dev);
 522
 523         /* Register the driver */
 524         ret = platform_driver_register(&cros_ec_dev_driver);
 525         if (ret < 0) {
 526                 pr_warn(CROS_EC_DEV_NAME ": can't register driver: %d\n", ret);
 527                 goto failed_devreg;
 528         }
 529         return 0;
 530
 531 failed_devreg:
 532         unregister_chrdev_region(MKDEV(ec_major, 0), CROS_MAX_DEV);
 533 failed_chrdevreg:
 534         class_unregister(&cros_class);
 535         return ret;
 536 }
 537
 538 static void __exit cros_ec_dev_exit(void)
 539 {
 540         platform_driver_unregister(&cros_ec_dev_driver);
 541         unregister_chrdev(ec_major, CROS_EC_DEV_NAME);
 542         class_unregister(&cros_class);
 543 }
 544
 545 module_init(cros_ec_dev_init);
 546 module_exit(cros_ec_dev_exit);
 547
 548 MODULE_ALIAS("platform:" DRV_NAME);
 549 MODULE_AUTHOR("Bill Richardson <wfrichar@chromium.org>");
 550 MODULE_DESCRIPTION("Userspace interface to the Chrome OS Embedded Controller");
 551 MODULE_VERSION("1.0");
 552 MODULE_LICENSE("GPL");