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	mei_me_cl_put(me_cl);
80
81	ret = mei_cl_link(cl, MEI_WD_HOST_CLIENT_ID);
82
83	if (ret < 0) {
84		dev_info(dev->dev, "wd: failed link client\n");
85		return ret;
86	}
87
88	ret = mei_cl_connect(cl, NULL);
89
90	if (ret) {
91		dev_err(dev->dev, "wd: failed to connect = %d\n", ret);
92		mei_cl_unlink(cl);
93		return ret;
94	}
95
96	ret = mei_watchdog_register(dev);
97	if (ret) {
98		mei_cl_disconnect(cl);
99		mei_cl_unlink(cl);
100	}
101	return ret;
102}
103
104/**
105 * mei_wd_send - sends watch dog message to fw.
106 *
107 * @dev: the device structure
108 *
109 * Return: 0 if success,
110 *	-EIO when message send fails
111 *	-EINVAL when invalid message is to be sent
112 *	-ENODEV on flow control failure
113 */
114int mei_wd_send(struct mei_device *dev)
115{
116	struct mei_cl *cl = &dev->wd_cl;
117	struct mei_msg_hdr hdr;
118	int ret;
119
120	hdr.host_addr = cl->host_client_id;
121	hdr.me_addr = cl->me_client_id;
122	hdr.msg_complete = 1;
123	hdr.reserved = 0;
124	hdr.internal = 0;
125
126	if (!memcmp(dev->wd_data, mei_start_wd_params, MEI_WD_HDR_SIZE))
127		hdr.length = MEI_WD_START_MSG_SIZE;
128	else if (!memcmp(dev->wd_data, mei_stop_wd_params, MEI_WD_HDR_SIZE))
129		hdr.length = MEI_WD_STOP_MSG_SIZE;
130	else {
131		dev_err(dev->dev, "wd: invalid message is to be sent, aborting\n");
132		return -EINVAL;
133	}
134
135	ret = mei_write_message(dev, &hdr, dev->wd_data);
136	if (ret) {
137		dev_err(dev->dev, "wd: write message failed\n");
138		return ret;
139	}
140
141	ret = mei_cl_flow_ctrl_reduce(cl);
142	if (ret) {
143		dev_err(dev->dev, "wd: flow_ctrl_reduce failed.\n");
144		return ret;
145	}
146
147	return 0;
148}
149
150/**
151 * mei_wd_stop - sends watchdog stop message to fw.
152 *
153 * @dev: the device structure
154 *
155 * Return: 0 if success
156 * on error:
157 *	-EIO    when message send fails
158 *	-EINVAL when invalid message is to be sent
159 *	-ETIME  on message timeout
160 */
161int mei_wd_stop(struct mei_device *dev)
162{
163	struct mei_cl *cl = &dev->wd_cl;
164	int ret;
165
166	if (!mei_cl_is_connected(cl) ||
167	    dev->wd_state != MEI_WD_RUNNING)
168		return 0;
169
170	memcpy(dev->wd_data, mei_stop_wd_params, MEI_WD_STOP_MSG_SIZE);
171
172	dev->wd_state = MEI_WD_STOPPING;
173
174	ret = mei_cl_flow_ctrl_creds(cl);
175	if (ret < 0)
176		goto err;
177
178	if (ret && mei_hbuf_acquire(dev)) {
179		ret = mei_wd_send(dev);
180		if (ret)
181			goto err;
182		dev->wd_pending = false;
183	} else {
184		dev->wd_pending = true;
185	}
186
187	mutex_unlock(&dev->device_lock);
188
189	ret = wait_event_timeout(dev->wait_stop_wd,
190				dev->wd_state == MEI_WD_IDLE,
191				msecs_to_jiffies(MEI_WD_STOP_TIMEOUT));
192	mutex_lock(&dev->device_lock);
193	if (dev->wd_state != MEI_WD_IDLE) {
194		/* timeout */
195		ret = -ETIME;
196		dev_warn(dev->dev, "wd: stop failed to complete ret=%d\n", ret);
197		goto err;
198	}
199	dev_dbg(dev->dev, "wd: stop completed after %u msec\n",
200			MEI_WD_STOP_TIMEOUT - jiffies_to_msecs(ret));
201	return 0;
202err:
203	return ret;
204}
205
206/**
207 * mei_wd_ops_start - wd start command from the watchdog core.
208 *
209 * @wd_dev: watchdog device struct
210 *
211 * Return: 0 if success, negative errno code for failure
212 */
213static int mei_wd_ops_start(struct watchdog_device *wd_dev)
214{
215	struct mei_device *dev;
216	struct mei_cl *cl;
217	int err = -ENODEV;
218
219	dev = watchdog_get_drvdata(wd_dev);
220	if (!dev)
221		return -ENODEV;
222
223	cl = &dev->wd_cl;
224
225	mutex_lock(&dev->device_lock);
226
227	if (dev->dev_state != MEI_DEV_ENABLED) {
228		dev_dbg(dev->dev, "wd: dev_state != MEI_DEV_ENABLED  dev_state = %s\n",
229			mei_dev_state_str(dev->dev_state));
230		goto end_unlock;
231	}
232
233	if (!mei_cl_is_connected(cl)) {
234		cl_dbg(dev, cl, "MEI Driver is not connected to Watchdog Client\n");
235		goto end_unlock;
236	}
237
238	mei_wd_set_start_timeout(dev, dev->wd_timeout);
239
240	err = 0;
241end_unlock:
242	mutex_unlock(&dev->device_lock);
243	return err;
244}
245
246/**
247 * mei_wd_ops_stop -  wd stop command from the watchdog core.
248 *
249 * @wd_dev: watchdog device struct
250 *
251 * Return: 0 if success, negative errno code for failure
252 */
253static int mei_wd_ops_stop(struct watchdog_device *wd_dev)
254{
255	struct mei_device *dev;
256
257	dev = watchdog_get_drvdata(wd_dev);
258	if (!dev)
259		return -ENODEV;
260
261	mutex_lock(&dev->device_lock);
262	mei_wd_stop(dev);
263	mutex_unlock(&dev->device_lock);
264
265	return 0;
266}
267
268/**
269 * mei_wd_ops_ping - wd ping command from the watchdog core.
270 *
271 * @wd_dev: watchdog device struct
272 *
273 * Return: 0 if success, negative errno code for failure
274 */
275static int mei_wd_ops_ping(struct watchdog_device *wd_dev)
276{
277	struct mei_device *dev;
278	struct mei_cl *cl;
279	int ret;
280
281	dev = watchdog_get_drvdata(wd_dev);
282	if (!dev)
283		return -ENODEV;
284
285	cl = &dev->wd_cl;
286
287	mutex_lock(&dev->device_lock);
288
289	if (!mei_cl_is_connected(cl)) {
290		cl_err(dev, cl, "wd: not connected.\n");
291		ret = -ENODEV;
292		goto end;
293	}
294
295	dev->wd_state = MEI_WD_RUNNING;
296
297	ret = mei_cl_flow_ctrl_creds(cl);
298	if (ret < 0)
299		goto end;
300
301	/* Check if we can send the ping to HW*/
302	if (ret && mei_hbuf_acquire(dev)) {
303		dev_dbg(dev->dev, "wd: sending ping\n");
304
305		ret = mei_wd_send(dev);
306		if (ret)
307			goto end;
308		dev->wd_pending = false;
309	} else {
310		dev->wd_pending = true;
311	}
312
313end:
314	mutex_unlock(&dev->device_lock);
315	return ret;
316}
317
318/**
319 * mei_wd_ops_set_timeout - wd set timeout command from the watchdog core.
320 *
321 * @wd_dev: watchdog device struct
322 * @timeout: timeout value to set
323 *
324 * Return: 0 if success, negative errno code for failure
325 */
326static int mei_wd_ops_set_timeout(struct watchdog_device *wd_dev,
327		unsigned int timeout)
328{
329	struct mei_device *dev;
330
331	dev = watchdog_get_drvdata(wd_dev);
332	if (!dev)
333		return -ENODEV;
334
335	/* Check Timeout value */
336	if (timeout < MEI_WD_MIN_TIMEOUT || timeout > MEI_WD_MAX_TIMEOUT)
337		return -EINVAL;
338
339	mutex_lock(&dev->device_lock);
340
341	dev->wd_timeout = timeout;
342	wd_dev->timeout = timeout;
343	mei_wd_set_start_timeout(dev, dev->wd_timeout);
344
345	mutex_unlock(&dev->device_lock);
346
347	return 0;
348}
349
350/*
351 * Watchdog Device structs
352 */
353static const struct watchdog_ops wd_ops = {
354		.owner = THIS_MODULE,
355		.start = mei_wd_ops_start,
356		.stop = mei_wd_ops_stop,
357		.ping = mei_wd_ops_ping,
358		.set_timeout = mei_wd_ops_set_timeout,
359};
360static const struct watchdog_info wd_info = {
361		.identity = INTEL_AMT_WATCHDOG_ID,
362		.options = WDIOF_KEEPALIVEPING |
363			   WDIOF_SETTIMEOUT |
364			   WDIOF_ALARMONLY,
365};
366
367static struct watchdog_device amt_wd_dev = {
368		.info = &wd_info,
369		.ops = &wd_ops,
370		.timeout = MEI_WD_DEFAULT_TIMEOUT,
371		.min_timeout = MEI_WD_MIN_TIMEOUT,
372		.max_timeout = MEI_WD_MAX_TIMEOUT,
373};
374
375
376int mei_watchdog_register(struct mei_device *dev)
377{
378
379	int ret;
380
381	/* unlock to perserve correct locking order */
382	mutex_unlock(&dev->device_lock);
383	ret = watchdog_register_device(&amt_wd_dev);
384	mutex_lock(&dev->device_lock);
385	if (ret) {
386		dev_err(dev->dev, "wd: unable to register watchdog device = %d.\n",
387			ret);
388		return ret;
389	}
390
391	dev_dbg(dev->dev, "wd: successfully register watchdog interface.\n");
392	watchdog_set_drvdata(&amt_wd_dev, dev);
393	return 0;
394}
395
396void mei_watchdog_unregister(struct mei_device *dev)
397{
398	if (watchdog_get_drvdata(&amt_wd_dev) == NULL)
399		return;
400
401	watchdog_set_drvdata(&amt_wd_dev, NULL);
402	watchdog_unregister_device(&amt_wd_dev);
403}
404
405