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13#include <linux/init.h>
14#include <linux/device.h>
15#include <linux/fs.h>
16#include <linux/miscdevice.h>
17#include <linux/module.h>
18#include <linux/notifier.h>
19#include <linux/platform_data/cros_ec_chardev.h>
20#include <linux/platform_data/cros_ec_commands.h>
21#include <linux/platform_data/cros_ec_proto.h>
22#include <linux/platform_device.h>
23#include <linux/poll.h>
24#include <linux/slab.h>
25#include <linux/types.h>
26#include <linux/uaccess.h>
27
28#define DRV_NAME "cros-ec-chardev"
29
30
31#define CROS_MAX_EVENT_LEN PAGE_SIZE
32
33struct chardev_data {
34 struct cros_ec_dev *ec_dev;
35 struct miscdevice misc;
36};
37
38struct chardev_priv {
39 struct cros_ec_dev *ec_dev;
40 struct notifier_block notifier;
41 wait_queue_head_t wait_event;
42 unsigned long event_mask;
43 struct list_head events;
44 size_t event_len;
45};
46
47struct ec_event {
48 struct list_head node;
49 size_t size;
50 u8 event_type;
51 u8 data[];
52};
53
54static int ec_get_version(struct cros_ec_dev *ec, char *str, int maxlen)
55{
56 static const char * const current_image_name[] = {
57 "unknown", "read-only", "read-write", "invalid",
58 };
59 struct ec_response_get_version *resp;
60 struct cros_ec_command *msg;
61 int ret;
62
63 msg = kzalloc(sizeof(*msg) + sizeof(*resp), GFP_KERNEL);
64 if (!msg)
65 return -ENOMEM;
66
67 msg->command = EC_CMD_GET_VERSION + ec->cmd_offset;
68 msg->insize = sizeof(*resp);
69
70 ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
71 if (ret < 0) {
72 snprintf(str, maxlen,
73 "Unknown EC version, returned error: %d\n",
74 msg->result);
75 goto exit;
76 }
77
78 resp = (struct ec_response_get_version *)msg->data;
79 if (resp->current_image >= ARRAY_SIZE(current_image_name))
80 resp->current_image = 3;
81
82 snprintf(str, maxlen, "%s\n%s\n%s\n%s\n", CROS_EC_DEV_VERSION,
83 resp->version_string_ro, resp->version_string_rw,
84 current_image_name[resp->current_image]);
85
86 ret = 0;
87exit:
88 kfree(msg);
89 return ret;
90}
91
92static int cros_ec_chardev_mkbp_event(struct notifier_block *nb,
93 unsigned long queued_during_suspend,
94 void *_notify)
95{
96 struct chardev_priv *priv = container_of(nb, struct chardev_priv,
97 notifier);
98 struct cros_ec_device *ec_dev = priv->ec_dev->ec_dev;
99 struct ec_event *event;
100 unsigned long event_bit = 1 << ec_dev->event_data.event_type;
101 int total_size = sizeof(*event) + ec_dev->event_size;
102
103 if (!(event_bit & priv->event_mask) ||
104 (priv->event_len + total_size) > CROS_MAX_EVENT_LEN)
105 return NOTIFY_DONE;
106
107 event = kzalloc(total_size, GFP_KERNEL);
108 if (!event)
109 return NOTIFY_DONE;
110
111 event->size = ec_dev->event_size;
112 event->event_type = ec_dev->event_data.event_type;
113 memcpy(event->data, &ec_dev->event_data.data, ec_dev->event_size);
114
115 spin_lock(&priv->wait_event.lock);
116 list_add_tail(&event->node, &priv->events);
117 priv->event_len += total_size;
118 wake_up_locked(&priv->wait_event);
119 spin_unlock(&priv->wait_event.lock);
120
121 return NOTIFY_OK;
122}
123
124static struct ec_event *cros_ec_chardev_fetch_event(struct chardev_priv *priv,
125 bool fetch, bool block)
126{
127 struct ec_event *event;
128 int err;
129
130 spin_lock(&priv->wait_event.lock);
131 if (!block && list_empty(&priv->events)) {
132 event = ERR_PTR(-EWOULDBLOCK);
133 goto out;
134 }
135
136 if (!fetch) {
137 event = NULL;
138 goto out;
139 }
140
141 err = wait_event_interruptible_locked(priv->wait_event,
142 !list_empty(&priv->events));
143 if (err) {
144 event = ERR_PTR(err);
145 goto out;
146 }
147
148 event = list_first_entry(&priv->events, struct ec_event, node);
149 list_del(&event->node);
150 priv->event_len -= sizeof(*event) + event->size;
151
152out:
153 spin_unlock(&priv->wait_event.lock);
154 return event;
155}
156
157
158
159
160static int cros_ec_chardev_open(struct inode *inode, struct file *filp)
161{
162 struct miscdevice *mdev = filp->private_data;
163 struct cros_ec_dev *ec_dev = dev_get_drvdata(mdev->parent);
164 struct chardev_priv *priv;
165 int ret;
166
167 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
168 if (!priv)
169 return -ENOMEM;
170
171 priv->ec_dev = ec_dev;
172 filp->private_data = priv;
173 INIT_LIST_HEAD(&priv->events);
174 init_waitqueue_head(&priv->wait_event);
175 nonseekable_open(inode, filp);
176
177 priv->notifier.notifier_call = cros_ec_chardev_mkbp_event;
178 ret = blocking_notifier_chain_register(&ec_dev->ec_dev->event_notifier,
179 &priv->notifier);
180 if (ret) {
181 dev_err(ec_dev->dev, "failed to register event notifier\n");
182 kfree(priv);
183 }
184
185 return ret;
186}
187
188static __poll_t cros_ec_chardev_poll(struct file *filp, poll_table *wait)
189{
190 struct chardev_priv *priv = filp->private_data;
191
192 poll_wait(filp, &priv->wait_event, wait);
193
194 if (list_empty(&priv->events))
195 return 0;
196
197 return EPOLLIN | EPOLLRDNORM;
198}
199
200static ssize_t cros_ec_chardev_read(struct file *filp, char __user *buffer,
201 size_t length, loff_t *offset)
202{
203 char msg[sizeof(struct ec_response_get_version) +
204 sizeof(CROS_EC_DEV_VERSION)];
205 struct chardev_priv *priv = filp->private_data;
206 struct cros_ec_dev *ec_dev = priv->ec_dev;
207 size_t count;
208 int ret;
209
210 if (priv->event_mask) {
211 struct ec_event *event;
212
213 event = cros_ec_chardev_fetch_event(priv, length != 0,
214 !(filp->f_flags & O_NONBLOCK));
215 if (IS_ERR(event))
216 return PTR_ERR(event);
217
218
219
220
221 if (length == 0)
222 return 0;
223
224
225 count = min(length, event->size + 1);
226 ret = copy_to_user(buffer, &event->event_type, count);
227 kfree(event);
228 if (ret)
229 return -EFAULT;
230 *offset = count;
231 return count;
232 }
233
234
235
236
237 if (*offset != 0)
238 return 0;
239
240 ret = ec_get_version(ec_dev, msg, sizeof(msg));
241 if (ret)
242 return ret;
243
244 count = min(length, strlen(msg));
245
246 if (copy_to_user(buffer, msg, count))
247 return -EFAULT;
248
249 *offset = count;
250 return count;
251}
252
253static int cros_ec_chardev_release(struct inode *inode, struct file *filp)
254{
255 struct chardev_priv *priv = filp->private_data;
256 struct cros_ec_dev *ec_dev = priv->ec_dev;
257 struct ec_event *event, *e;
258
259 blocking_notifier_chain_unregister(&ec_dev->ec_dev->event_notifier,
260 &priv->notifier);
261
262 list_for_each_entry_safe(event, e, &priv->events, node) {
263 list_del(&event->node);
264 kfree(event);
265 }
266 kfree(priv);
267
268 return 0;
269}
270
271
272
273
274static long cros_ec_chardev_ioctl_xcmd(struct cros_ec_dev *ec, void __user *arg)
275{
276 struct cros_ec_command *s_cmd;
277 struct cros_ec_command u_cmd;
278 long ret;
279
280 if (copy_from_user(&u_cmd, arg, sizeof(u_cmd)))
281 return -EFAULT;
282
283 if (u_cmd.outsize > EC_MAX_MSG_BYTES ||
284 u_cmd.insize > EC_MAX_MSG_BYTES)
285 return -EINVAL;
286
287 s_cmd = kmalloc(sizeof(*s_cmd) + max(u_cmd.outsize, u_cmd.insize),
288 GFP_KERNEL);
289 if (!s_cmd)
290 return -ENOMEM;
291
292 if (copy_from_user(s_cmd, arg, sizeof(*s_cmd) + u_cmd.outsize)) {
293 ret = -EFAULT;
294 goto exit;
295 }
296
297 if (u_cmd.outsize != s_cmd->outsize ||
298 u_cmd.insize != s_cmd->insize) {
299 ret = -EINVAL;
300 goto exit;
301 }
302
303 s_cmd->command += ec->cmd_offset;
304 ret = cros_ec_cmd_xfer_status(ec->ec_dev, s_cmd);
305
306 if (ret < 0)
307 goto exit;
308
309 if (copy_to_user(arg, s_cmd, sizeof(*s_cmd) + s_cmd->insize))
310 ret = -EFAULT;
311exit:
312 kfree(s_cmd);
313 return ret;
314}
315
316static long cros_ec_chardev_ioctl_readmem(struct cros_ec_dev *ec,
317 void __user *arg)
318{
319 struct cros_ec_device *ec_dev = ec->ec_dev;
320 struct cros_ec_readmem s_mem = { };
321 long num;
322
323
324 if (!ec_dev->cmd_readmem)
325 return -ENOTTY;
326
327 if (copy_from_user(&s_mem, arg, sizeof(s_mem)))
328 return -EFAULT;
329
330 num = ec_dev->cmd_readmem(ec_dev, s_mem.offset, s_mem.bytes,
331 s_mem.buffer);
332 if (num <= 0)
333 return num;
334
335 if (copy_to_user((void __user *)arg, &s_mem, sizeof(s_mem)))
336 return -EFAULT;
337
338 return num;
339}
340
341static long cros_ec_chardev_ioctl(struct file *filp, unsigned int cmd,
342 unsigned long arg)
343{
344 struct chardev_priv *priv = filp->private_data;
345 struct cros_ec_dev *ec = priv->ec_dev;
346
347 if (_IOC_TYPE(cmd) != CROS_EC_DEV_IOC)
348 return -ENOTTY;
349
350 switch (cmd) {
351 case CROS_EC_DEV_IOCXCMD:
352 return cros_ec_chardev_ioctl_xcmd(ec, (void __user *)arg);
353 case CROS_EC_DEV_IOCRDMEM:
354 return cros_ec_chardev_ioctl_readmem(ec, (void __user *)arg);
355 case CROS_EC_DEV_IOCEVENTMASK:
356 priv->event_mask = arg;
357 return 0;
358 }
359
360 return -ENOTTY;
361}
362
363static const struct file_operations chardev_fops = {
364 .open = cros_ec_chardev_open,
365 .poll = cros_ec_chardev_poll,
366 .read = cros_ec_chardev_read,
367 .release = cros_ec_chardev_release,
368 .unlocked_ioctl = cros_ec_chardev_ioctl,
369#ifdef CONFIG_COMPAT
370 .compat_ioctl = cros_ec_chardev_ioctl,
371#endif
372};
373
374static int cros_ec_chardev_probe(struct platform_device *pdev)
375{
376 struct cros_ec_dev *ec_dev = dev_get_drvdata(pdev->dev.parent);
377 struct cros_ec_platform *ec_platform = dev_get_platdata(ec_dev->dev);
378 struct chardev_data *data;
379
380
381 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
382 if (!data)
383 return -ENOMEM;
384
385 data->ec_dev = ec_dev;
386 data->misc.minor = MISC_DYNAMIC_MINOR;
387 data->misc.fops = &chardev_fops;
388 data->misc.name = ec_platform->ec_name;
389 data->misc.parent = pdev->dev.parent;
390
391 dev_set_drvdata(&pdev->dev, data);
392
393 return misc_register(&data->misc);
394}
395
396static int cros_ec_chardev_remove(struct platform_device *pdev)
397{
398 struct chardev_data *data = dev_get_drvdata(&pdev->dev);
399
400 misc_deregister(&data->misc);
401
402 return 0;
403}
404
405static struct platform_driver cros_ec_chardev_driver = {
406 .driver = {
407 .name = DRV_NAME,
408 },
409 .probe = cros_ec_chardev_probe,
410 .remove = cros_ec_chardev_remove,
411};
412
413module_platform_driver(cros_ec_chardev_driver);
414
415MODULE_ALIAS("platform:" DRV_NAME);
416MODULE_AUTHOR("Enric Balletbo i Serra <enric.balletbo@collabora.com>");
417MODULE_DESCRIPTION("ChromeOS EC Miscellaneous Character Driver");
418MODULE_LICENSE("GPL");
419
