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