1/*
2 *
3 * Intel Management Engine Interface (Intel MEI) Linux driver
4 * Copyright (c) 2003-2012, Intel Corporation.
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms and conditions of the GNU General Public License,
8 * version 2, as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
13 * more details.
14 *
15 */
16#include <linux/kernel.h>
17#include <linux/module.h>
18#include <linux/moduleparam.h>
19#include <linux/device.h>
20#include <linux/sched.h>
21#include <linux/watchdog.h>
22
23#include <linux/mei.h>
24
25#include "mei_dev.h"
26#include "hbm.h"
27#include "client.h"
28
29static const u8 mei_start_wd_params[] = { 0x02, 0x12, 0x13, 0x10 };
30static const u8 mei_stop_wd_params[] = { 0x02, 0x02, 0x14, 0x10 };
31
32/*
33 * AMT Watchdog Device
34 */
35#define INTEL_AMT_WATCHDOG_ID "INTCAMT"
36
37/* UUIDs for AMT F/W clients */
38const uuid_le mei_wd_guid = UUID_LE(0x05B79A6F, 0x4628, 0x4D7F, 0x89,
39						0x9D, 0xA9, 0x15, 0x14, 0xCB,
40						0x32, 0xAB);
41
42static void mei_wd_set_start_timeout(struct mei_device *dev, u16 timeout)
43{
44	dev_dbg(dev->dev, "wd: set timeout=%d.\n", timeout);
45	memcpy(dev->wd_data, mei_start_wd_params, MEI_WD_HDR_SIZE);
46	memcpy(dev->wd_data + MEI_WD_HDR_SIZE, &timeout, sizeof(u16));
47}
48
49/**
50 * mei_wd_host_init - connect to the watchdog client
51 *
52 * @dev: the device structure
53 *
54 * Return: -ENOTTY if wd client cannot be found
55 *         -EIO if write has failed
56 *         0 on success
57 */
58int mei_wd_host_init(struct mei_device *dev)
59{
60	struct mei_cl *cl = &dev->wd_cl;
61	struct mei_me_client *me_cl;
62	int ret;
63
64	mei_cl_init(cl, dev);
65
66	dev->wd_timeout = MEI_WD_DEFAULT_TIMEOUT;
67	dev->wd_state = MEI_WD_IDLE;
68
69
70	/* check for valid client id */
71	me_cl = mei_me_cl_by_uuid(dev, &mei_wd_guid);
72	if (!me_cl) {
73		dev_info(dev->dev, "wd: failed to find the client\n");
74		return -ENOTTY;
75	}
76
77	cl->me_client_id = me_cl->client_id;
78	cl->cl_uuid = me_cl->props.protocol_name;
79
80	ret = mei_cl_link(cl, MEI_WD_HOST_CLIENT_ID);
81
82	if (ret < 0) {
83		dev_info(dev->dev, "wd: failed link client\n");
84		return ret;
85	}
86
87	ret = mei_cl_connect(cl, NULL);
88
89	if (ret) {
90		dev_err(dev->dev, "wd: failed to connect = %d\n", ret);
91		mei_cl_unlink(cl);
92		return ret;
93	}
94
95	ret = mei_watchdog_register(dev);
96	if (ret) {
97		mei_cl_disconnect(cl);
98		mei_cl_unlink(cl);
99	}
100	return ret;
101}
102
103/**
104 * mei_wd_send - sends watch dog message to fw.
105 *
106 * @dev: the device structure
107 *
108 * Return: 0 if success,
109 *	-EIO when message send fails
110 *	-EINVAL when invalid message is to be sent
111 *	-ENODEV on flow control failure
112 */
113int mei_wd_send(struct mei_device *dev)
114{
115	struct mei_cl *cl = &dev->wd_cl;
116	struct mei_msg_hdr hdr;
117	int ret;
118
119	hdr.host_addr = cl->host_client_id;
120	hdr.me_addr = cl->me_client_id;
121	hdr.msg_complete = 1;
122	hdr.reserved = 0;
123	hdr.internal = 0;
124
125	if (!memcmp(dev->wd_data, mei_start_wd_params, MEI_WD_HDR_SIZE))
126		hdr.length = MEI_WD_START_MSG_SIZE;
127	else if (!memcmp(dev->wd_data, mei_stop_wd_params, MEI_WD_HDR_SIZE))
128		hdr.length = MEI_WD_STOP_MSG_SIZE;
129	else {
130		dev_err(dev->dev, "wd: invalid message is to be sent, aborting\n");
131		return -EINVAL;
132	}
133
134	ret = mei_write_message(dev, &hdr, dev->wd_data);
135	if (ret) {
136		dev_err(dev->dev, "wd: write message failed\n");
137		return ret;
138	}
139
140	ret = mei_cl_flow_ctrl_reduce(cl);
141	if (ret) {
142		dev_err(dev->dev, "wd: flow_ctrl_reduce failed.\n");
143		return ret;
144	}
145
146	return 0;
147}
148
149/**
150 * mei_wd_stop - sends watchdog stop message to fw.
151 *
152 * @dev: the device structure
153 *
154 * Return: 0 if success
155 * on error:
156 *	-EIO    when message send fails
157 *	-EINVAL when invalid message is to be sent
158 *	-ETIME  on message timeout
159 */
160int mei_wd_stop(struct mei_device *dev)
161{
162	int ret;
163
164	if (dev->wd_cl.state != MEI_FILE_CONNECTED ||
165	    dev->wd_state != MEI_WD_RUNNING)
166		return 0;
167
168	memcpy(dev->wd_data, mei_stop_wd_params, MEI_WD_STOP_MSG_SIZE);
169
170	dev->wd_state = MEI_WD_STOPPING;
171
172	ret = mei_cl_flow_ctrl_creds(&dev->wd_cl);
173	if (ret < 0)
174		goto err;
175
176	if (ret && mei_hbuf_acquire(dev)) {
177		ret = mei_wd_send(dev);
178		if (ret)
179			goto err;
180		dev->wd_pending = false;
181	} else {
182		dev->wd_pending = true;
183	}
184
185	mutex_unlock(&dev->device_lock);
186
187	ret = wait_event_timeout(dev->wait_stop_wd,
188				dev->wd_state == MEI_WD_IDLE,
189				msecs_to_jiffies(MEI_WD_STOP_TIMEOUT));
190	mutex_lock(&dev->device_lock);
191	if (dev->wd_state != MEI_WD_IDLE) {
192		/* timeout */
193		ret = -ETIME;
194		dev_warn(dev->dev, "wd: stop failed to complete ret=%d\n", ret);
195		goto err;
196	}
197	dev_dbg(dev->dev, "wd: stop completed after %u msec\n",
198			MEI_WD_STOP_TIMEOUT - jiffies_to_msecs(ret));
199	return 0;
200err:
201	return ret;
202}
203
204/*
205 * mei_wd_ops_start - wd start command from the watchdog core.
206 *
207 * @wd_dev - watchdog device struct
208 *
209 * Return: 0 if success, negative errno code for failure
210 */
211static int mei_wd_ops_start(struct watchdog_device *wd_dev)
212{
213	int err = -ENODEV;
214	struct mei_device *dev;
215
216	dev = watchdog_get_drvdata(wd_dev);
217	if (!dev)
218		return -ENODEV;
219
220	mutex_lock(&dev->device_lock);
221
222	if (dev->dev_state != MEI_DEV_ENABLED) {
223		dev_dbg(dev->dev, "wd: dev_state != MEI_DEV_ENABLED  dev_state = %s\n",
224			mei_dev_state_str(dev->dev_state));
225		goto end_unlock;
226	}
227
228	if (dev->wd_cl.state != MEI_FILE_CONNECTED)	{
229		dev_dbg(dev->dev, "MEI Driver is not connected to Watchdog Client\n");
230		goto end_unlock;
231	}
232
233	mei_wd_set_start_timeout(dev, dev->wd_timeout);
234
235	err = 0;
236end_unlock:
237	mutex_unlock(&dev->device_lock);
238	return err;
239}
240
241/*
242 * mei_wd_ops_stop -  wd stop command from the watchdog core.
243 *
244 * @wd_dev - watchdog device struct
245 *
246 * Return: 0 if success, negative errno code for failure
247 */
248static int mei_wd_ops_stop(struct watchdog_device *wd_dev)
249{
250	struct mei_device *dev;
251
252	dev = watchdog_get_drvdata(wd_dev);
253	if (!dev)
254		return -ENODEV;
255
256	mutex_lock(&dev->device_lock);
257	mei_wd_stop(dev);
258	mutex_unlock(&dev->device_lock);
259
260	return 0;
261}
262
263/*
264 * mei_wd_ops_ping - wd ping command from the watchdog core.
265 *
266 * @wd_dev - watchdog device struct
267 *
268 * Return: 0 if success, negative errno code for failure
269 */
270static int mei_wd_ops_ping(struct watchdog_device *wd_dev)
271{
272	struct mei_device *dev;
273	int ret;
274
275	dev = watchdog_get_drvdata(wd_dev);
276	if (!dev)
277		return -ENODEV;
278
279	mutex_lock(&dev->device_lock);
280
281	if (dev->wd_cl.state != MEI_FILE_CONNECTED) {
282		dev_err(dev->dev, "wd: not connected.\n");
283		ret = -ENODEV;
284		goto end;
285	}
286
287	dev->wd_state = MEI_WD_RUNNING;
288
289	ret = mei_cl_flow_ctrl_creds(&dev->wd_cl);
290	if (ret < 0)
291		goto end;
292	/* Check if we can send the ping to HW*/
293	if (ret && mei_hbuf_acquire(dev)) {
294
295		dev_dbg(dev->dev, "wd: sending ping\n");
296
297		ret = mei_wd_send(dev);
298		if (ret)
299			goto end;
300		dev->wd_pending = false;
301	} else {
302		dev->wd_pending = true;
303	}
304
305end:
306	mutex_unlock(&dev->device_lock);
307	return ret;
308}
309
310/*
311 * mei_wd_ops_set_timeout - wd set timeout command from the watchdog core.
312 *
313 * @wd_dev - watchdog device struct
314 * @timeout - timeout value to set
315 *
316 * Return: 0 if success, negative errno code for failure
317 */
318static int mei_wd_ops_set_timeout(struct watchdog_device *wd_dev,
319		unsigned int timeout)
320{
321	struct mei_device *dev;
322
323	dev = watchdog_get_drvdata(wd_dev);
324	if (!dev)
325		return -ENODEV;
326
327	/* Check Timeout value */
328	if (timeout < MEI_WD_MIN_TIMEOUT || timeout > MEI_WD_MAX_TIMEOUT)
329		return -EINVAL;
330
331	mutex_lock(&dev->device_lock);
332
333	dev->wd_timeout = timeout;
334	wd_dev->timeout = timeout;
335	mei_wd_set_start_timeout(dev, dev->wd_timeout);
336
337	mutex_unlock(&dev->device_lock);
338
339	return 0;
340}
341
342/*
343 * Watchdog Device structs
344 */
345static const struct watchdog_ops wd_ops = {
346		.owner = THIS_MODULE,
347		.start = mei_wd_ops_start,
348		.stop = mei_wd_ops_stop,
349		.ping = mei_wd_ops_ping,
350		.set_timeout = mei_wd_ops_set_timeout,
351};
352static const struct watchdog_info wd_info = {
353		.identity = INTEL_AMT_WATCHDOG_ID,
354		.options = WDIOF_KEEPALIVEPING |
355			   WDIOF_SETTIMEOUT |
356			   WDIOF_ALARMONLY,
357};
358
359static struct watchdog_device amt_wd_dev = {
360		.info = &wd_info,
361		.ops = &wd_ops,
362		.timeout = MEI_WD_DEFAULT_TIMEOUT,
363		.min_timeout = MEI_WD_MIN_TIMEOUT,
364		.max_timeout = MEI_WD_MAX_TIMEOUT,
365};
366
367
368int mei_watchdog_register(struct mei_device *dev)
369{
370
371	int ret;
372
373	/* unlock to perserve correct locking order */
374	mutex_unlock(&dev->device_lock);
375	ret = watchdog_register_device(&amt_wd_dev);
376	mutex_lock(&dev->device_lock);
377	if (ret) {
378		dev_err(dev->dev, "wd: unable to register watchdog device = %d.\n",
379			ret);
380		return ret;
381	}
382
383	dev_dbg(dev->dev, "wd: successfully register watchdog interface.\n");
384	watchdog_set_drvdata(&amt_wd_dev, dev);
385	return 0;
386}
387
388void mei_watchdog_unregister(struct mei_device *dev)
389{
390	if (watchdog_get_drvdata(&amt_wd_dev) == NULL)
391		return;
392
393	watchdog_set_drvdata(&amt_wd_dev, NULL);
394	watchdog_unregister_device(&amt_wd_dev);
395}
396
397