1/*
  2 * cros_ec_debugfs - debug logs for Chrome OS EC
  3 *
  4 * Copyright 2015 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/circ_buf.h>
 21#include <linux/debugfs.h>
 22#include <linux/delay.h>
 23#include <linux/fs.h>
 24#include <linux/mfd/cros_ec.h>
 25#include <linux/mfd/cros_ec_commands.h>
 26#include <linux/mutex.h>
 27#include <linux/poll.h>
 28#include <linux/sched.h>
 29#include <linux/slab.h>
 30#include <linux/wait.h>
 31
 32#define LOG_SHIFT		14
 33#define LOG_SIZE		(1 << LOG_SHIFT)
 34#define LOG_POLL_SEC		10
 35
 36#define CIRC_ADD(idx, size, value)	(((idx) + (value)) & ((size) - 1))
 37
 38/* struct cros_ec_debugfs - ChromeOS EC debugging information
 39 *
 40 * @ec: EC device this debugfs information belongs to
 41 * @dir: dentry for debugfs files
 42 * @log_buffer: circular buffer for console log information
 43 * @read_msg: preallocated EC command and buffer to read console log
 44 * @log_mutex: mutex to protect circular buffer
 45 * @log_wq: waitqueue for log readers
 46 * @log_poll_work: recurring task to poll EC for new console log data
 47 * @panicinfo_blob: panicinfo debugfs blob
 48 */
 49struct cros_ec_debugfs {
 50	struct cros_ec_dev *ec;
 51	struct dentry *dir;
 52	/* EC log */
 53	struct circ_buf log_buffer;
 54	struct cros_ec_command *read_msg;
 55	struct mutex log_mutex;
 56	wait_queue_head_t log_wq;
 57	struct delayed_work log_poll_work;
 58	/* EC panicinfo */
 59	struct debugfs_blob_wrapper panicinfo_blob;
 60};
 61
 62/*
 63 * We need to make sure that the EC log buffer on the UART is large enough,
 64 * so that it is unlikely enough to overlow within LOG_POLL_SEC.
 65 */
 66static void cros_ec_console_log_work(struct work_struct *__work)
 67{
 68	struct cros_ec_debugfs *debug_info =
 69		container_of(to_delayed_work(__work),
 70			     struct cros_ec_debugfs,
 71			     log_poll_work);
 72	struct cros_ec_dev *ec = debug_info->ec;
 73	struct circ_buf *cb = &debug_info->log_buffer;
 74	struct cros_ec_command snapshot_msg = {
 75		.command = EC_CMD_CONSOLE_SNAPSHOT + ec->cmd_offset,
 76	};
 77
 78	struct ec_params_console_read_v1 *read_params =
 79		(struct ec_params_console_read_v1 *)debug_info->read_msg->data;
 80	uint8_t *ec_buffer = (uint8_t *)debug_info->read_msg->data;
 81	int idx;
 82	int buf_space;
 83	int ret;
 84
 85	ret = cros_ec_cmd_xfer(ec->ec_dev, &snapshot_msg);
 86	if (ret < 0) {
 87		dev_err(ec->dev, "EC communication failed\n");
 88		goto resched;
 89	}
 90	if (snapshot_msg.result != EC_RES_SUCCESS) {
 91		dev_err(ec->dev, "EC failed to snapshot the console log\n");
 92		goto resched;
 93	}
 94
 95	/* Loop until we have read everything, or there's an error. */
 96	mutex_lock(&debug_info->log_mutex);
 97	buf_space = CIRC_SPACE(cb->head, cb->tail, LOG_SIZE);
 98
 99	while (1) {
100		if (!buf_space) {
101			dev_info_once(ec->dev,
102				      "Some logs may have been dropped...\n");
103			break;
104		}
105
106		memset(read_params, '\0', sizeof(*read_params));
107		read_params->subcmd = CONSOLE_READ_RECENT;
108		ret = cros_ec_cmd_xfer(ec->ec_dev, debug_info->read_msg);
109		if (ret < 0) {
110			dev_err(ec->dev, "EC communication failed\n");
111			break;
112		}
113		if (debug_info->read_msg->result != EC_RES_SUCCESS) {
114			dev_err(ec->dev,
115				"EC failed to read the console log\n");
116			break;
117		}
118
119		/* If the buffer is empty, we're done here. */
120		if (ret == 0 || ec_buffer[0] == '\0')
121			break;
122
123		idx = 0;
124		while (idx < ret && ec_buffer[idx] != '\0' && buf_space > 0) {
125			cb->buf[cb->head] = ec_buffer[idx];
126			cb->head = CIRC_ADD(cb->head, LOG_SIZE, 1);
127			idx++;
128			buf_space--;
129		}
130
131		wake_up(&debug_info->log_wq);
132	}
133
134	mutex_unlock(&debug_info->log_mutex);
135
136resched:
137	schedule_delayed_work(&debug_info->log_poll_work,
138			      msecs_to_jiffies(LOG_POLL_SEC * 1000));
139}
140
141static int cros_ec_console_log_open(struct inode *inode, struct file *file)
142{
143	file->private_data = inode->i_private;
144
145	return nonseekable_open(inode, file);
146}
147
148static ssize_t cros_ec_console_log_read(struct file *file, char __user *buf,
149					size_t count, loff_t *ppos)
150{
151	struct cros_ec_debugfs *debug_info = file->private_data;
152	struct circ_buf *cb = &debug_info->log_buffer;
153	ssize_t ret;
154
155	mutex_lock(&debug_info->log_mutex);
156
157	while (!CIRC_CNT(cb->head, cb->tail, LOG_SIZE)) {
158		if (file->f_flags & O_NONBLOCK) {
159			ret = -EAGAIN;
160			goto error;
161		}
162
163		mutex_unlock(&debug_info->log_mutex);
164
165		ret = wait_event_interruptible(debug_info->log_wq,
166					CIRC_CNT(cb->head, cb->tail, LOG_SIZE));
167		if (ret < 0)
168			return ret;
169
170		mutex_lock(&debug_info->log_mutex);
171	}
172
173	/* Only copy until the end of the circular buffer, and let userspace
174	 * retry to get the rest of the data.
175	 */
176	ret = min_t(size_t, CIRC_CNT_TO_END(cb->head, cb->tail, LOG_SIZE),
177		    count);
178
179	if (copy_to_user(buf, cb->buf + cb->tail, ret)) {
180		ret = -EFAULT;
181		goto error;
182	}
183
184	cb->tail = CIRC_ADD(cb->tail, LOG_SIZE, ret);
185
186error:
187	mutex_unlock(&debug_info->log_mutex);
188	return ret;
189}
190
191static __poll_t cros_ec_console_log_poll(struct file *file,
192					     poll_table *wait)
193{
194	struct cros_ec_debugfs *debug_info = file->private_data;
195	__poll_t mask = 0;
196
197	poll_wait(file, &debug_info->log_wq, wait);
198
199	mutex_lock(&debug_info->log_mutex);
200	if (CIRC_CNT(debug_info->log_buffer.head,
201		     debug_info->log_buffer.tail,
202		     LOG_SIZE))
203		mask |= EPOLLIN | EPOLLRDNORM;
204	mutex_unlock(&debug_info->log_mutex);
205
206	return mask;
207}
208
209static int cros_ec_console_log_release(struct inode *inode, struct file *file)
210{
211	return 0;
212}
213
214static ssize_t cros_ec_pdinfo_read(struct file *file,
215				   char __user *user_buf,
216				   size_t count,
217				   loff_t *ppos)
218{
219	char read_buf[EC_USB_PD_MAX_PORTS * 40], *p = read_buf;
220	struct cros_ec_debugfs *debug_info = file->private_data;
221	struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
222	struct {
223		struct cros_ec_command msg;
224		union {
225			struct ec_response_usb_pd_control_v1 resp;
226			struct ec_params_usb_pd_control params;
227		};
228	} __packed ec_buf;
229	struct cros_ec_command *msg;
230	struct ec_response_usb_pd_control_v1 *resp;
231	struct ec_params_usb_pd_control *params;
232	int i;
233
234	msg = &ec_buf.msg;
235	params = (struct ec_params_usb_pd_control *)msg->data;
236	resp = (struct ec_response_usb_pd_control_v1 *)msg->data;
237
238	msg->command = EC_CMD_USB_PD_CONTROL;
239	msg->version = 1;
240	msg->insize = sizeof(*resp);
241	msg->outsize = sizeof(*params);
242
243	/*
244	 * Read status from all PD ports until failure, typically caused
245	 * by attempting to read status on a port that doesn't exist.
246	 */
247	for (i = 0; i < EC_USB_PD_MAX_PORTS; ++i) {
248		params->port = i;
249		params->role = 0;
250		params->mux = 0;
251		params->swap = 0;
252
253		if (cros_ec_cmd_xfer_status(ec_dev, msg) < 0)
254			break;
255
256		p += scnprintf(p, sizeof(read_buf) + read_buf - p,
257			       "p%d: %s en:%.2x role:%.2x pol:%.2x\n", i,
258			       resp->state, resp->enabled, resp->role,
259			       resp->polarity);
260	}
261
262	return simple_read_from_buffer(user_buf, count, ppos,
263				       read_buf, p - read_buf);
264}
265
266const struct file_operations cros_ec_console_log_fops = {
267	.owner = THIS_MODULE,
268	.open = cros_ec_console_log_open,
269	.read = cros_ec_console_log_read,
270	.llseek = no_llseek,
271	.poll = cros_ec_console_log_poll,
272	.release = cros_ec_console_log_release,
273};
274
275const struct file_operations cros_ec_pdinfo_fops = {
276	.owner = THIS_MODULE,
277	.open = simple_open,
278	.read = cros_ec_pdinfo_read,
279	.llseek = default_llseek,
280};
281
282static int ec_read_version_supported(struct cros_ec_dev *ec)
283{
284	struct ec_params_get_cmd_versions_v1 *params;
285	struct ec_response_get_cmd_versions *response;
286	int ret;
287
288	struct cros_ec_command *msg;
289
290	msg = kzalloc(sizeof(*msg) + max(sizeof(*params), sizeof(*response)),
291		GFP_KERNEL);
292	if (!msg)
293		return 0;
294
295	msg->command = EC_CMD_GET_CMD_VERSIONS + ec->cmd_offset;
296	msg->outsize = sizeof(*params);
297	msg->insize = sizeof(*response);
298
299	params = (struct ec_params_get_cmd_versions_v1 *)msg->data;
300	params->cmd = EC_CMD_CONSOLE_READ;
301	response = (struct ec_response_get_cmd_versions *)msg->data;
302
303	ret = cros_ec_cmd_xfer(ec->ec_dev, msg) >= 0 &&
304		msg->result == EC_RES_SUCCESS &&
305		(response->version_mask & EC_VER_MASK(1));
306
307	kfree(msg);
308
309	return ret;
310}
311
312static int cros_ec_create_console_log(struct cros_ec_debugfs *debug_info)
313{
314	struct cros_ec_dev *ec = debug_info->ec;
315	char *buf;
316	int read_params_size;
317	int read_response_size;
318
319	if (!ec_read_version_supported(ec)) {
320		dev_warn(ec->dev,
321			"device does not support reading the console log\n");
322		return 0;
323	}
324
325	buf = devm_kzalloc(ec->dev, LOG_SIZE, GFP_KERNEL);
326	if (!buf)
327		return -ENOMEM;
328
329	read_params_size = sizeof(struct ec_params_console_read_v1);
330	read_response_size = ec->ec_dev->max_response;
331	debug_info->read_msg = devm_kzalloc(ec->dev,
332		sizeof(*debug_info->read_msg) +
333			max(read_params_size, read_response_size), GFP_KERNEL);
334	if (!debug_info->read_msg)
335		return -ENOMEM;
336
337	debug_info->read_msg->version = 1;
338	debug_info->read_msg->command = EC_CMD_CONSOLE_READ + ec->cmd_offset;
339	debug_info->read_msg->outsize = read_params_size;
340	debug_info->read_msg->insize = read_response_size;
341
342	debug_info->log_buffer.buf = buf;
343	debug_info->log_buffer.head = 0;
344	debug_info->log_buffer.tail = 0;
345
346	mutex_init(&debug_info->log_mutex);
347	init_waitqueue_head(&debug_info->log_wq);
348
349	if (!debugfs_create_file("console_log",
350				 S_IFREG | 0444,
351				 debug_info->dir,
352				 debug_info,
353				 &cros_ec_console_log_fops))
354		return -ENOMEM;
355
356	INIT_DELAYED_WORK(&debug_info->log_poll_work,
357			  cros_ec_console_log_work);
358	schedule_delayed_work(&debug_info->log_poll_work, 0);
359
360	return 0;
361}
362
363static void cros_ec_cleanup_console_log(struct cros_ec_debugfs *debug_info)
364{
365	if (debug_info->log_buffer.buf) {
366		cancel_delayed_work_sync(&debug_info->log_poll_work);
367		mutex_destroy(&debug_info->log_mutex);
368	}
369}
370
371static int cros_ec_create_panicinfo(struct cros_ec_debugfs *debug_info)
372{
373	struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
374	int ret;
375	struct cros_ec_command *msg;
376	int insize;
377
378	insize = ec_dev->max_response;
379
380	msg = devm_kzalloc(debug_info->ec->dev,
381			sizeof(*msg) + insize, GFP_KERNEL);
382	if (!msg)
383		return -ENOMEM;
384
385	msg->command = EC_CMD_GET_PANIC_INFO;
386	msg->insize = insize;
387
388	ret = cros_ec_cmd_xfer(ec_dev, msg);
389	if (ret < 0) {
390		dev_warn(debug_info->ec->dev, "Cannot read panicinfo.\n");
391		ret = 0;
392		goto free;
393	}
394
395	/* No panic data */
396	if (ret == 0)
397		goto free;
398
399	debug_info->panicinfo_blob.data = msg->data;
400	debug_info->panicinfo_blob.size = ret;
401
402	if (!debugfs_create_blob("panicinfo",
403				 S_IFREG | 0444,
404				 debug_info->dir,
405				 &debug_info->panicinfo_blob)) {
406		ret = -ENOMEM;
407		goto free;
408	}
409
410	return 0;
411
412free:
413	devm_kfree(debug_info->ec->dev, msg);
414	return ret;
415}
416
417static int cros_ec_create_pdinfo(struct cros_ec_debugfs *debug_info)
418{
419	if (!debugfs_create_file("pdinfo", 0444, debug_info->dir, debug_info,
420				 &cros_ec_pdinfo_fops))
421		return -ENOMEM;
422
423	return 0;
424}
425
426int cros_ec_debugfs_init(struct cros_ec_dev *ec)
427{
428	struct cros_ec_platform *ec_platform = dev_get_platdata(ec->dev);
429	const char *name = ec_platform->ec_name;
430	struct cros_ec_debugfs *debug_info;
431	int ret;
432
433	debug_info = devm_kzalloc(ec->dev, sizeof(*debug_info), GFP_KERNEL);
434	if (!debug_info)
435		return -ENOMEM;
436
437	debug_info->ec = ec;
438	debug_info->dir = debugfs_create_dir(name, NULL);
439	if (!debug_info->dir)
440		return -ENOMEM;
441
442	ret = cros_ec_create_panicinfo(debug_info);
443	if (ret)
444		goto remove_debugfs;
445
446	ret = cros_ec_create_console_log(debug_info);
447	if (ret)
448		goto remove_debugfs;
449
450	ret = cros_ec_create_pdinfo(debug_info);
451	if (ret)
452		goto remove_debugfs;
453
454	ec->debug_info = debug_info;
455
456	return 0;
457
458remove_debugfs:
459	debugfs_remove_recursive(debug_info->dir);
460	return ret;
461}
462EXPORT_SYMBOL(cros_ec_debugfs_init);
463
464void cros_ec_debugfs_remove(struct cros_ec_dev *ec)
465{
466	if (!ec->debug_info)
467		return;
468
469	debugfs_remove_recursive(ec->debug_info->dir);
470	cros_ec_cleanup_console_log(ec->debug_info);
471}
472EXPORT_SYMBOL(cros_ec_debugfs_remove);