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