2 * cros_ec_dev - expose the Chrome OS Embedded Controller to user-space
4 * Copyright (C) 2014 Google, Inc.
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.
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.
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/>.
21 #include <linux/module.h>
22 #include <linux/platform_device.h>
23 #include <linux/slab.h>
24 #include <linux/uaccess.h>
26 #include "cros_ec_dev.h"
28 /* Device variables */
29 #define CROS_MAX_DEV 128
32 static const struct attribute_group *cros_ec_groups[] = {
34 &cros_ec_lightbar_attr_group,
38 static struct class cros_class = {
41 .dev_groups = cros_ec_groups,
44 /* Basic communication */
45 static int ec_get_version(struct cros_ec_dev *ec, char *str, int maxlen)
47 struct ec_response_get_version *resp;
48 static const char * const current_image_name[] = {
49 "unknown", "read-only", "read-write", "invalid",
51 struct cros_ec_command *msg;
54 msg = kmalloc(sizeof(*msg) + sizeof(*resp), GFP_KERNEL);
59 msg->command = EC_CMD_GET_VERSION + ec->cmd_offset;
60 msg->insize = sizeof(*resp);
63 ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
67 if (msg->result != EC_RES_SUCCESS) {
69 "%s\nUnknown EC version: EC returned %d\n",
70 CROS_EC_DEV_VERSION, msg->result);
75 resp = (struct ec_response_get_version *)msg->data;
76 if (resp->current_image >= ARRAY_SIZE(current_image_name))
77 resp->current_image = 3; /* invalid */
79 snprintf(str, maxlen, "%s\n%s\n%s\n%s\n", CROS_EC_DEV_VERSION,
80 resp->version_string_ro, resp->version_string_rw,
81 current_image_name[resp->current_image]);
90 static int ec_device_open(struct inode *inode, struct file *filp)
92 struct cros_ec_dev *ec = container_of(inode->i_cdev,
93 struct cros_ec_dev, cdev);
94 filp->private_data = ec;
95 nonseekable_open(inode, filp);
99 static int ec_device_release(struct inode *inode, struct file *filp)
104 static ssize_t ec_device_read(struct file *filp, char __user *buffer,
105 size_t length, loff_t *offset)
107 struct cros_ec_dev *ec = filp->private_data;
108 char msg[sizeof(struct ec_response_get_version) +
109 sizeof(CROS_EC_DEV_VERSION)];
116 ret = ec_get_version(ec, msg, sizeof(msg));
120 count = min(length, strlen(msg));
122 if (copy_to_user(buffer, msg, count))
130 static long ec_device_ioctl_xcmd(struct cros_ec_dev *ec, void __user *arg)
133 struct cros_ec_command u_cmd;
134 struct cros_ec_command *s_cmd;
136 if (copy_from_user(&u_cmd, arg, sizeof(u_cmd)))
139 s_cmd = kmalloc(sizeof(*s_cmd) + max(u_cmd.outsize, u_cmd.insize),
144 if (copy_from_user(s_cmd, arg, sizeof(*s_cmd) + u_cmd.outsize)) {
149 s_cmd->command += ec->cmd_offset;
150 ret = cros_ec_cmd_xfer(ec->ec_dev, s_cmd);
151 /* Only copy data to userland if data was received. */
155 if (copy_to_user(arg, s_cmd, sizeof(*s_cmd) + u_cmd.insize))
162 static long ec_device_ioctl_readmem(struct cros_ec_dev *ec, void __user *arg)
164 struct cros_ec_device *ec_dev = ec->ec_dev;
165 struct cros_ec_readmem s_mem = { };
168 /* Not every platform supports direct reads */
169 if (!ec_dev->cmd_readmem)
172 if (copy_from_user(&s_mem, arg, sizeof(s_mem)))
175 num = ec_dev->cmd_readmem(ec_dev, s_mem.offset, s_mem.bytes,
180 if (copy_to_user((void __user *)arg, &s_mem, sizeof(s_mem)))
186 static long ec_device_ioctl(struct file *filp, unsigned int cmd,
189 struct cros_ec_dev *ec = filp->private_data;
191 if (_IOC_TYPE(cmd) != CROS_EC_DEV_IOC)
195 case CROS_EC_DEV_IOCXCMD:
196 return ec_device_ioctl_xcmd(ec, (void __user *)arg);
197 case CROS_EC_DEV_IOCRDMEM:
198 return ec_device_ioctl_readmem(ec, (void __user *)arg);
204 /* Module initialization */
205 static const struct file_operations fops = {
206 .open = ec_device_open,
207 .release = ec_device_release,
208 .read = ec_device_read,
209 .unlocked_ioctl = ec_device_ioctl,
212 static void __remove(struct device *dev)
214 struct cros_ec_dev *ec = container_of(dev, struct cros_ec_dev,
219 static int ec_device_probe(struct platform_device *pdev)
221 int retval = -ENOMEM;
222 struct device *dev = &pdev->dev;
223 struct cros_ec_platform *ec_platform = dev_get_platdata(dev);
224 dev_t devno = MKDEV(ec_major, pdev->id);
225 struct cros_ec_dev *ec = kzalloc(sizeof(*ec), GFP_KERNEL);
230 dev_set_drvdata(dev, ec);
231 ec->ec_dev = dev_get_drvdata(dev->parent);
233 ec->cmd_offset = ec_platform->cmd_offset;
234 device_initialize(&ec->class_dev);
235 cdev_init(&ec->cdev, &fops);
238 * Add the character device
239 * Link cdev to the class device to be sure device is not used
240 * before unbinding it.
242 ec->cdev.kobj.parent = &ec->class_dev.kobj;
243 retval = cdev_add(&ec->cdev, devno, 1);
245 dev_err(dev, ": failed to add character device\n");
246 goto cdev_add_failed;
250 * Add the class device
251 * Link to the character device for creating the /dev entry
254 ec->class_dev.devt = ec->cdev.dev;
255 ec->class_dev.class = &cros_class;
256 ec->class_dev.parent = dev;
257 ec->class_dev.release = __remove;
259 retval = dev_set_name(&ec->class_dev, "%s", ec_platform->ec_name);
261 dev_err(dev, "dev_set_name failed => %d\n", retval);
262 goto set_named_failed;
265 retval = device_add(&ec->class_dev);
267 dev_err(dev, "device_register failed => %d\n", retval);
275 dev_set_drvdata(dev, NULL);
282 static int ec_device_remove(struct platform_device *pdev)
284 struct cros_ec_dev *ec = dev_get_drvdata(&pdev->dev);
286 device_unregister(&ec->class_dev);
290 static struct platform_driver cros_ec_dev_driver = {
292 .name = "cros-ec-ctl",
294 .probe = ec_device_probe,
295 .remove = ec_device_remove,
298 static int __init cros_ec_dev_init(void)
303 ret = class_register(&cros_class);
305 pr_err(CROS_EC_DEV_NAME ": failed to register device class\n");
309 /* Get a range of minor numbers (starting with 0) to work with */
310 ret = alloc_chrdev_region(&dev, 0, CROS_MAX_DEV, CROS_EC_DEV_NAME);
312 pr_err(CROS_EC_DEV_NAME ": alloc_chrdev_region() failed\n");
313 goto failed_chrdevreg;
315 ec_major = MAJOR(dev);
317 /* Register the driver */
318 ret = platform_driver_register(&cros_ec_dev_driver);
320 pr_warn(CROS_EC_DEV_NAME ": can't register driver: %d\n", ret);
326 unregister_chrdev_region(MKDEV(ec_major, 0), CROS_MAX_DEV);
328 class_unregister(&cros_class);
332 static void __exit cros_ec_dev_exit(void)
334 platform_driver_unregister(&cros_ec_dev_driver);
335 unregister_chrdev(ec_major, CROS_EC_DEV_NAME);
336 class_unregister(&cros_class);
339 module_init(cros_ec_dev_init);
340 module_exit(cros_ec_dev_exit);
342 MODULE_AUTHOR("Bill Richardson <wfrichar@chromium.org>");
343 MODULE_DESCRIPTION("Userspace interface to the Chrome OS Embedded Controller");
344 MODULE_VERSION("1.0");
345 MODULE_LICENSE("GPL");