[linux-2.6-block.git] / drivers / watchdog / mei_wdt.c

/*
 * Intel Management Engine Interface (Intel MEI) Linux driver
 * Copyright (c) 2015, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/debugfs.h>
#include <linux/watchdog.h>

#include <linux/uuid.h>
#include <linux/mei_cl_bus.h>

/*
 * iAMT Watchdog Device
 */
#define INTEL_AMT_WATCHDOG_ID "iamt_wdt"

#define MEI_WDT_DEFAULT_TIMEOUT   120  /* seconds */
#define MEI_WDT_MIN_TIMEOUT       120  /* seconds */
#define MEI_WDT_MAX_TIMEOUT     65535  /* seconds */

/* Commands */
#define MEI_MANAGEMENT_CONTROL 0x02

/* MEI Management Control version number */
#define MEI_MC_VERSION_NUMBER  0x10

/* Sub Commands */
#define MEI_MC_START_WD_TIMER_REQ  0x13
#define MEI_MC_STOP_WD_TIMER_REQ   0x14

/**
 * enum mei_wdt_state - internal watchdog state
 *
 * @MEI_WDT_IDLE: wd is idle and not opened
 * @MEI_WDT_START: wd was opened, start was called
 * @MEI_WDT_RUNNING: wd is expecting keep alive pings
 * @MEI_WDT_STOPPING: wd is stopping and will move to IDLE
 */
enum mei_wdt_state {
	MEI_WDT_IDLE,
	MEI_WDT_START,
	MEI_WDT_RUNNING,
	MEI_WDT_STOPPING,
};

#if IS_ENABLED(CONFIG_DEBUG_FS)
static const char *mei_wdt_state_str(enum mei_wdt_state state)
{
	switch (state) {
	case MEI_WDT_IDLE:
		return "IDLE";
	case MEI_WDT_START:
		return "START";
	case MEI_WDT_RUNNING:
		return "RUNNING";
	case MEI_WDT_STOPPING:
		return "STOPPING";
	default:
		return "unknown";
	}
}
#endif /* CONFIG_DEBUG_FS */

/**
 * struct mei_wdt - mei watchdog driver
 * @wdd: watchdog device
 *
 * @cldev: mei watchdog client device
 * @state: watchdog internal state
 * @timeout: watchdog current timeout
 *
 * @dbgfs_dir: debugfs dir entry
 */
struct mei_wdt {
	struct watchdog_device wdd;

	struct mei_cl_device *cldev;
	enum mei_wdt_state state;
	u16 timeout;

#if IS_ENABLED(CONFIG_DEBUG_FS)
	struct dentry *dbgfs_dir;
#endif /* CONFIG_DEBUG_FS */
};

/*
 * struct mei_mc_hdr - Management Control Command Header
 *
 * @command: Management Control (0x2)
 * @bytecount: Number of bytes in the message beyond this byte
 * @subcommand: Management Control Subcommand
 * @versionnumber: Management Control Version (0x10)
 */
struct mei_mc_hdr {
	u8 command;
	u8 bytecount;
	u8 subcommand;
	u8 versionnumber;
};

/**
 * struct mei_wdt_start_request watchdog start/ping
 *
 * @hdr: Management Control Command Header
 * @timeout: timeout value
 * @reserved: reserved (legacy)
 */
struct mei_wdt_start_request {
	struct mei_mc_hdr hdr;
	u16 timeout;
	u8 reserved[17];
} __packed;

/**
 * struct mei_wdt_stop_request - watchdog stop
 *
 * @hdr: Management Control Command Header
 */
struct mei_wdt_stop_request {
	struct mei_mc_hdr hdr;
} __packed;

/**
 * mei_wdt_ping - send wd start/ping command
 *
 * @wdt: mei watchdog device
 *
 * Return: 0 on success,
 *         negative errno code on failure
 */
static int mei_wdt_ping(struct mei_wdt *wdt)
{
	struct mei_wdt_start_request req;
	const size_t req_len = sizeof(req);
	int ret;

	memset(&req, 0, req_len);
	req.hdr.command = MEI_MANAGEMENT_CONTROL;
	req.hdr.bytecount = req_len - offsetof(struct mei_mc_hdr, subcommand);
	req.hdr.subcommand = MEI_MC_START_WD_TIMER_REQ;
	req.hdr.versionnumber = MEI_MC_VERSION_NUMBER;
	req.timeout = wdt->timeout;

	ret = mei_cldev_send(wdt->cldev, (u8 *)&req, req_len);
	if (ret < 0)
		return ret;

	return 0;
}

/**
 * mei_wdt_stop - send wd stop command
 *
 * @wdt: mei watchdog device
 *
 * Return: 0 on success,
 *         negative errno code on failure
 */
static int mei_wdt_stop(struct mei_wdt *wdt)
{
	struct mei_wdt_stop_request req;
	const size_t req_len = sizeof(req);
	int ret;

	memset(&req, 0, req_len);
	req.hdr.command = MEI_MANAGEMENT_CONTROL;
	req.hdr.bytecount = req_len - offsetof(struct mei_mc_hdr, subcommand);
	req.hdr.subcommand = MEI_MC_STOP_WD_TIMER_REQ;
	req.hdr.versionnumber = MEI_MC_VERSION_NUMBER;

	ret = mei_cldev_send(wdt->cldev, (u8 *)&req, req_len);
	if (ret < 0)
		return ret;

	return 0;
}

/**
 * mei_wdt_ops_start - wd start command from the watchdog core.
 *
 * @wdd: watchdog device
 *
 * Return: 0 on success or -ENODEV;
 */
static int mei_wdt_ops_start(struct watchdog_device *wdd)
{
	struct mei_wdt *wdt = watchdog_get_drvdata(wdd);

	wdt->state = MEI_WDT_START;
	wdd->timeout = wdt->timeout;
	return 0;
}

/**
 * mei_wdt_ops_stop - wd stop command from the watchdog core.
 *
 * @wdd: watchdog device
 *
 * Return: 0 if success, negative errno code for failure
 */
static int mei_wdt_ops_stop(struct watchdog_device *wdd)
{
	struct mei_wdt *wdt = watchdog_get_drvdata(wdd);
	int ret;

	if (wdt->state != MEI_WDT_RUNNING)
		return 0;

	wdt->state = MEI_WDT_STOPPING;

	ret = mei_wdt_stop(wdt);
	if (ret)
		return ret;

	wdt->state = MEI_WDT_IDLE;

	return 0;
}

/**
 * mei_wdt_ops_ping - wd ping command from the watchdog core.
 *
 * @wdd: watchdog device
 *
 * Return: 0 if success, negative errno code on failure
 */
static int mei_wdt_ops_ping(struct watchdog_device *wdd)
{
	struct mei_wdt *wdt = watchdog_get_drvdata(wdd);
	int ret;

	if (wdt->state != MEI_WDT_START && wdt->state != MEI_WDT_RUNNING)
		return 0;

	ret = mei_wdt_ping(wdt);
	if (ret)
		return ret;

	wdt->state = MEI_WDT_RUNNING;

	return 0;
}

/**
 * mei_wdt_ops_set_timeout - wd set timeout command from the watchdog core.
 *
 * @wdd: watchdog device
 * @timeout: timeout value to set
 *
 * Return: 0 if success, negative errno code for failure
 */
static int mei_wdt_ops_set_timeout(struct watchdog_device *wdd,
				   unsigned int timeout)
{

	struct mei_wdt *wdt = watchdog_get_drvdata(wdd);

	/* valid value is already checked by the caller */
	wdt->timeout = timeout;
	wdd->timeout = timeout;

	return 0;
}

static const struct watchdog_ops wd_ops = {
	.owner       = THIS_MODULE,
	.start       = mei_wdt_ops_start,
	.stop        = mei_wdt_ops_stop,
	.ping        = mei_wdt_ops_ping,
	.set_timeout = mei_wdt_ops_set_timeout,
};

/* not const as the firmware_version field need to be retrieved */
static struct watchdog_info wd_info = {
	.identity = INTEL_AMT_WATCHDOG_ID,
	.options  = WDIOF_KEEPALIVEPING |
		    WDIOF_SETTIMEOUT |
		    WDIOF_ALARMONLY,
};

/**
 * mei_wdt_unregister - unregister from the watchdog subsystem
 *
 * @wdt: mei watchdog device
 */
static void mei_wdt_unregister(struct mei_wdt *wdt)
{
	watchdog_unregister_device(&wdt->wdd);
	watchdog_set_drvdata(&wdt->wdd, NULL);
}

/**
 * mei_wdt_register - register with the watchdog subsystem
 *
 * @wdt: mei watchdog device
 *
 * Return: 0 if success, negative errno code for failure
 */
static int mei_wdt_register(struct mei_wdt *wdt)
{
	struct device *dev;
	int ret;

	if (!wdt || !wdt->cldev)
		return -EINVAL;

	dev = &wdt->cldev->dev;

	wdt->wdd.info = &wd_info;
	wdt->wdd.ops = &wd_ops;
	wdt->wdd.parent = dev;
	wdt->wdd.timeout = MEI_WDT_DEFAULT_TIMEOUT;
	wdt->wdd.min_timeout = MEI_WDT_MIN_TIMEOUT;
	wdt->wdd.max_timeout = MEI_WDT_MAX_TIMEOUT;

	watchdog_set_drvdata(&wdt->wdd, wdt);
	ret = watchdog_register_device(&wdt->wdd);
	if (ret) {
		dev_err(dev, "unable to register watchdog device = %d.\n", ret);
		watchdog_set_drvdata(&wdt->wdd, NULL);
	}

	return ret;
}

#if IS_ENABLED(CONFIG_DEBUG_FS)

static ssize_t mei_dbgfs_read_state(struct file *file, char __user *ubuf,
				    size_t cnt, loff_t *ppos)
{
	struct mei_wdt *wdt = file->private_data;
	const size_t bufsz = 32;
	char buf[bufsz];
	ssize_t pos;

	pos = scnprintf(buf, bufsz, "state: %s\n",
			 mei_wdt_state_str(wdt->state));

	return simple_read_from_buffer(ubuf, cnt, ppos, buf, pos);
}

static const struct file_operations dbgfs_fops_state = {
	.open = simple_open,
	.read = mei_dbgfs_read_state,
	.llseek = generic_file_llseek,
};

static void dbgfs_unregister(struct mei_wdt *wdt)
{
	debugfs_remove_recursive(wdt->dbgfs_dir);
	wdt->dbgfs_dir = NULL;
}

static int dbgfs_register(struct mei_wdt *wdt)
{
	struct dentry *dir, *f;

	dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
	if (!dir)
		return -ENOMEM;

	wdt->dbgfs_dir = dir;
	f = debugfs_create_file("state", S_IRUSR, dir, wdt, &dbgfs_fops_state);
	if (!f)
		goto err;

	return 0;
err:
	dbgfs_unregister(wdt);
	return -ENODEV;
}

#else

static inline void dbgfs_unregister(struct mei_wdt *wdt) {}

static inline int dbgfs_register(struct mei_wdt *wdt)
{
	return 0;
}
#endif /* CONFIG_DEBUG_FS */

static int mei_wdt_probe(struct mei_cl_device *cldev,
			 const struct mei_cl_device_id *id)
{
	struct mei_wdt *wdt;
	int ret;

	wdt = kzalloc(sizeof(struct mei_wdt), GFP_KERNEL);
	if (!wdt)
		return -ENOMEM;

	wdt->timeout = MEI_WDT_DEFAULT_TIMEOUT;
	wdt->state = MEI_WDT_IDLE;
	wdt->cldev = cldev;
	mei_cldev_set_drvdata(cldev, wdt);

	ret = mei_cldev_enable(cldev);
	if (ret < 0) {
		dev_err(&cldev->dev, "Could not enable cl device\n");
		goto err_out;
	}

	wd_info.firmware_version = mei_cldev_ver(cldev);

	ret = mei_wdt_register(wdt);
	if (ret)
		goto err_disable;

	if (dbgfs_register(wdt))
		dev_warn(&cldev->dev, "cannot register debugfs\n");

	return 0;

err_disable:
	mei_cldev_disable(cldev);

err_out:
	kfree(wdt);

	return ret;
}

static int mei_wdt_remove(struct mei_cl_device *cldev)
{
	struct mei_wdt *wdt = mei_cldev_get_drvdata(cldev);

	mei_wdt_unregister(wdt);

	mei_cldev_disable(cldev);

	dbgfs_unregister(wdt);

	kfree(wdt);

	return 0;
}

#define MEI_UUID_WD UUID_LE(0x05B79A6F, 0x4628, 0x4D7F, \
			    0x89, 0x9D, 0xA9, 0x15, 0x14, 0xCB, 0x32, 0xAB)

static struct mei_cl_device_id mei_wdt_tbl[] = {
	{ .uuid = MEI_UUID_WD, .version = 0x1},
	/* required last entry */
	{ }
};
MODULE_DEVICE_TABLE(mei, mei_wdt_tbl);

static struct mei_cl_driver mei_wdt_driver = {
	.id_table = mei_wdt_tbl,
	.name = KBUILD_MODNAME,

	.probe = mei_wdt_probe,
	.remove = mei_wdt_remove,
};

static int __init mei_wdt_init(void)
{
	int ret;

	ret = mei_cldev_driver_register(&mei_wdt_driver);
	if (ret) {
		pr_err(KBUILD_MODNAME ": module registration failed\n");
		return ret;
	}
	return 0;
}

static void __exit mei_wdt_exit(void)
{
	mei_cldev_driver_unregister(&mei_wdt_driver);
}

module_init(mei_wdt_init);
module_exit(mei_wdt_exit);

MODULE_AUTHOR("Intel Corporation");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Device driver for Intel MEI iAMT watchdog");
Commit	Line	Data
222818c3 TW	1	/*
	2	* Intel Management Engine Interface (Intel MEI) Linux driver
	3	* Copyright (c) 2015, Intel Corporation.
	4	*
	5	* This program is free software; you can redistribute it and/or modify it
	6	* under the terms and conditions of the GNU General Public License,
	7	* version 2, as published by the Free Software Foundation.
	8	*
	9	* This program is distributed in the hope it will be useful, but WITHOUT
	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	12	* more details.
	13	*/
	14
	15	#include <linux/module.h>
	16	#include <linux/slab.h>
	17	#include <linux/interrupt.h>
c9cf20ee	18	#include <linux/debugfs.h>
222818c3 TW	19	#include <linux/watchdog.h>
	20
	21	#include <linux/uuid.h>
	22	#include <linux/mei_cl_bus.h>
	23
	24	/*
	25	* iAMT Watchdog Device
	26	*/
	27	#define INTEL_AMT_WATCHDOG_ID "iamt_wdt"
	28
	29	#define MEI_WDT_DEFAULT_TIMEOUT 120 /* seconds */
	30	#define MEI_WDT_MIN_TIMEOUT 120 /* seconds */
	31	#define MEI_WDT_MAX_TIMEOUT 65535 /* seconds */
	32
	33	/* Commands */
	34	#define MEI_MANAGEMENT_CONTROL 0x02
	35
	36	/* MEI Management Control version number */
	37	#define MEI_MC_VERSION_NUMBER 0x10
	38
	39	/* Sub Commands */
	40	#define MEI_MC_START_WD_TIMER_REQ 0x13
	41	#define MEI_MC_STOP_WD_TIMER_REQ 0x14
	42
	43	/**
	44	* enum mei_wdt_state - internal watchdog state
	45	*
	46	* @MEI_WDT_IDLE: wd is idle and not opened
	47	* @MEI_WDT_START: wd was opened, start was called
	48	* @MEI_WDT_RUNNING: wd is expecting keep alive pings
	49	* @MEI_WDT_STOPPING: wd is stopping and will move to IDLE
	50	*/
	51	enum mei_wdt_state {
	52	MEI_WDT_IDLE,
	53	MEI_WDT_START,
	54	MEI_WDT_RUNNING,
	55	MEI_WDT_STOPPING,
	56	};
	57
c9cf20ee TW	58	#if IS_ENABLED(CONFIG_DEBUG_FS)
	59	static const char *mei_wdt_state_str(enum mei_wdt_state state)
	60	{
	61	switch (state) {
	62	case MEI_WDT_IDLE:
	63	return "IDLE";
	64	case MEI_WDT_START:
	65	return "START";
	66	case MEI_WDT_RUNNING:
	67	return "RUNNING";
	68	case MEI_WDT_STOPPING:
	69	return "STOPPING";
	70	default:
	71	return "unknown";
	72	}
	73	}
	74	#endif /* CONFIG_DEBUG_FS */
	75
222818c3 TW	76	/**
	77	* struct mei_wdt - mei watchdog driver
	78	* @wdd: watchdog device
	79	*
	80	* @cldev: mei watchdog client device
	81	* @state: watchdog internal state
	82	* @timeout: watchdog current timeout
c9cf20ee TW	83	*
c9cf20ee TW	84	* @dbgfs_dir: debugfs dir entry
222818c3 TW	85	*/
	86	struct mei_wdt {
	87	struct watchdog_device wdd;
	88
	89	struct mei_cl_device *cldev;
	90	enum mei_wdt_state state;
	91	u16 timeout;
c9cf20ee TW	92
	93	#if IS_ENABLED(CONFIG_DEBUG_FS)
	94	struct dentry *dbgfs_dir;
	95	#endif /* CONFIG_DEBUG_FS */
222818c3 TW	96	};
	97
	98	/*
	99	* struct mei_mc_hdr - Management Control Command Header
	100	*
	101	* @command: Management Control (0x2)
	102	* @bytecount: Number of bytes in the message beyond this byte
	103	* @subcommand: Management Control Subcommand
	104	* @versionnumber: Management Control Version (0x10)
	105	*/
	106	struct mei_mc_hdr {
	107	u8 command;
	108	u8 bytecount;
	109	u8 subcommand;
	110	u8 versionnumber;
	111	};
	112
	113	/**
	114	* struct mei_wdt_start_request watchdog start/ping
	115	*
	116	* @hdr: Management Control Command Header
	117	* @timeout: timeout value
	118	* @reserved: reserved (legacy)
	119	*/
	120	struct mei_wdt_start_request {
	121	struct mei_mc_hdr hdr;
	122	u16 timeout;
	123	u8 reserved[17];
	124	} __packed;
	125
	126	/**
	127	* struct mei_wdt_stop_request - watchdog stop
	128	*
	129	* @hdr: Management Control Command Header
	130	*/
	131	struct mei_wdt_stop_request {
	132	struct mei_mc_hdr hdr;
	133	} __packed;
	134
	135	/**
	136	* mei_wdt_ping - send wd start/ping command
	137	*
	138	* @wdt: mei watchdog device
	139	*
	140	* Return: 0 on success,
	141	* negative errno code on failure
	142	*/
	143	static int mei_wdt_ping(struct mei_wdt *wdt)
	144	{
	145	struct mei_wdt_start_request req;
	146	const size_t req_len = sizeof(req);
	147	int ret;
	148
	149	memset(&req, 0, req_len);
	150	req.hdr.command = MEI_MANAGEMENT_CONTROL;
	151	req.hdr.bytecount = req_len - offsetof(struct mei_mc_hdr, subcommand);
	152	req.hdr.subcommand = MEI_MC_START_WD_TIMER_REQ;
	153	req.hdr.versionnumber = MEI_MC_VERSION_NUMBER;
	154	req.timeout = wdt->timeout;
	155
	156	ret = mei_cldev_send(wdt->cldev, (u8 *)&req, req_len);
	157	if (ret < 0)
	158	return ret;
	159
160	return 0;
161	}
162
163	/**
164	* mei_wdt_stop - send wd stop command
165	*
166	* @wdt: mei watchdog device
167	*
168	* Return: 0 on success,
169	* negative errno code on failure
170	*/
171	static int mei_wdt_stop(struct mei_wdt *wdt)
172	{
173	struct mei_wdt_stop_request req;
174	const size_t req_len = sizeof(req);
175	int ret;
176
177	memset(&req, 0, req_len);
178	req.hdr.command = MEI_MANAGEMENT_CONTROL;
179	req.hdr.bytecount = req_len - offsetof(struct mei_mc_hdr, subcommand);
180	req.hdr.subcommand = MEI_MC_STOP_WD_TIMER_REQ;
181	req.hdr.versionnumber = MEI_MC_VERSION_NUMBER;
182
183	ret = mei_cldev_send(wdt->cldev, (u8 *)&req, req_len);
184	if (ret < 0)
185	return ret;
186
187	return 0;
188	}
189
190	/**
191	* mei_wdt_ops_start - wd start command from the watchdog core.
192	*
193	* @wdd: watchdog device
194	*
195	* Return: 0 on success or -ENODEV;
196	*/
197	static int mei_wdt_ops_start(struct watchdog_device *wdd)
198	{
199	struct mei_wdt *wdt = watchdog_get_drvdata(wdd);
200
201	wdt->state = MEI_WDT_START;
202	wdd->timeout = wdt->timeout;
203	return 0;
204	}
205
206	/**
207	* mei_wdt_ops_stop - wd stop command from the watchdog core.
208	*
209	* @wdd: watchdog device
210	*
211	* Return: 0 if success, negative errno code for failure
212	*/
213	static int mei_wdt_ops_stop(struct watchdog_device *wdd)
214	{
215	struct mei_wdt *wdt = watchdog_get_drvdata(wdd);
216	int ret;
217
218	if (wdt->state != MEI_WDT_RUNNING)
219	return 0;
220
221	wdt->state = MEI_WDT_STOPPING;
222
223	ret = mei_wdt_stop(wdt);
224	if (ret)
225	return ret;
226
227	wdt->state = MEI_WDT_IDLE;
228
229	return 0;
230	}
231
232	/**
233	* mei_wdt_ops_ping - wd ping command from the watchdog core.
234	*
235	* @wdd: watchdog device
236	*
237	* Return: 0 if success, negative errno code on failure
238	*/
239	static int mei_wdt_ops_ping(struct watchdog_device *wdd)
240	{
241	struct mei_wdt *wdt = watchdog_get_drvdata(wdd);
242	int ret;
243
244	if (wdt->state != MEI_WDT_START && wdt->state != MEI_WDT_RUNNING)
245	return 0;
246
247	ret = mei_wdt_ping(wdt);
248	if (ret)
249	return ret;
250
251	wdt->state = MEI_WDT_RUNNING;
252
253	return 0;
254	}
255
256	/**
257	* mei_wdt_ops_set_timeout - wd set timeout command from the watchdog core.
258	*
259	* @wdd: watchdog device
260	* @timeout: timeout value to set
261	*
262	* Return: 0 if success, negative errno code for failure
263	*/
264	static int mei_wdt_ops_set_timeout(struct watchdog_device *wdd,
265	unsigned int timeout)
266	{
267
268	struct mei_wdt *wdt = watchdog_get_drvdata(wdd);
269
270	/* valid value is already checked by the caller */
271	wdt->timeout = timeout;
272	wdd->timeout = timeout;
273
274	return 0;
275	}
276
277	static const struct watchdog_ops wd_ops = {
278	.owner = THIS_MODULE,
279	.start = mei_wdt_ops_start,
280	.stop = mei_wdt_ops_stop,
281	.ping = mei_wdt_ops_ping,
282	.set_timeout = mei_wdt_ops_set_timeout,
283	};
284
285	/* not const as the firmware_version field need to be retrieved */
286	static struct watchdog_info wd_info = {
287	.identity = INTEL_AMT_WATCHDOG_ID,
288	.options = WDIOF_KEEPALIVEPING \|
289	WDIOF_SETTIMEOUT \|
290	WDIOF_ALARMONLY,
291	};
292
293	/**
294	* mei_wdt_unregister - unregister from the watchdog subsystem
295	*
296	* @wdt: mei watchdog device
297	*/
298	static void mei_wdt_unregister(struct mei_wdt *wdt)
299	{
300	watchdog_unregister_device(&wdt->wdd);
301	watchdog_set_drvdata(&wdt->wdd, NULL);
302	}
303
304	/**
305	* mei_wdt_register - register with the watchdog subsystem
306	*
307	* @wdt: mei watchdog device
308	*
309	* Return: 0 if success, negative errno code for failure
310	*/
311	static int mei_wdt_register(struct mei_wdt *wdt)
312	{
313	struct device *dev;
314	int ret;
315
316	if (!wdt \|\| !wdt->cldev)
317	return -EINVAL;
318
319	dev = &wdt->cldev->dev;
320
321	wdt->wdd.info = &wd_info;
322	wdt->wdd.ops = &wd_ops;
323	wdt->wdd.parent = dev;
324	wdt->wdd.timeout = MEI_WDT_DEFAULT_TIMEOUT;
325	wdt->wdd.min_timeout = MEI_WDT_MIN_TIMEOUT;
326	wdt->wdd.max_timeout = MEI_WDT_MAX_TIMEOUT;
327
328	watchdog_set_drvdata(&wdt->wdd, wdt);
329	ret = watchdog_register_device(&wdt->wdd);
330	if (ret) {
331	dev_err(dev, "unable to register watchdog device = %d.\n", ret);
332	watchdog_set_drvdata(&wdt->wdd, NULL);
333	}
334
335	return ret;
336	}
337
c9cf20ee TW	338	#if IS_ENABLED(CONFIG_DEBUG_FS)
	339
	340	static ssize_t mei_dbgfs_read_state(struct file file, char __user ubuf,
	341	size_t cnt, loff_t *ppos)
	342	{
	343	struct mei_wdt *wdt = file->private_data;
	344	const size_t bufsz = 32;
	345	char buf[bufsz];
	346	ssize_t pos;
	347
	348	pos = scnprintf(buf, bufsz, "state: %s\n",
	349	mei_wdt_state_str(wdt->state));
	350
	351	return simple_read_from_buffer(ubuf, cnt, ppos, buf, pos);
	352	}
	353
	354	static const struct file_operations dbgfs_fops_state = {
	355	.open = simple_open,
	356	.read = mei_dbgfs_read_state,
	357	.llseek = generic_file_llseek,
	358	};
	359
	360	static void dbgfs_unregister(struct mei_wdt *wdt)
	361	{
	362	debugfs_remove_recursive(wdt->dbgfs_dir);
	363	wdt->dbgfs_dir = NULL;
	364	}
	365
	366	static int dbgfs_register(struct mei_wdt *wdt)
	367	{
	368	struct dentry dir, f;
	369
	370	dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
	371	if (!dir)
	372	return -ENOMEM;
	373
	374	wdt->dbgfs_dir = dir;
	375	f = debugfs_create_file("state", S_IRUSR, dir, wdt, &dbgfs_fops_state);
	376	if (!f)
	377	goto err;
	378
	379	return 0;
	380	err:
	381	dbgfs_unregister(wdt);
	382	return -ENODEV;
	383	}
	384
	385	#else
	386
	387	static inline void dbgfs_unregister(struct mei_wdt *wdt) {}
	388
	389	static inline int dbgfs_register(struct mei_wdt *wdt)
	390	{
	391	return 0;
	392	}
	393	#endif /* CONFIG_DEBUG_FS */
	394
222818c3 TW	395	static int mei_wdt_probe(struct mei_cl_device *cldev,
	396	const struct mei_cl_device_id *id)
	397	{
	398	struct mei_wdt *wdt;
	399	int ret;
	400
	401	wdt = kzalloc(sizeof(struct mei_wdt), GFP_KERNEL);
	402	if (!wdt)
	403	return -ENOMEM;
	404
	405	wdt->timeout = MEI_WDT_DEFAULT_TIMEOUT;
	406	wdt->state = MEI_WDT_IDLE;
	407	wdt->cldev = cldev;
	408	mei_cldev_set_drvdata(cldev, wdt);
	409
	410	ret = mei_cldev_enable(cldev);
	411	if (ret < 0) {
	412	dev_err(&cldev->dev, "Could not enable cl device\n");
	413	goto err_out;
	414	}
	415
	416	wd_info.firmware_version = mei_cldev_ver(cldev);
	417
	418	ret = mei_wdt_register(wdt);
	419	if (ret)
	420	goto err_disable;
	421
c9cf20ee TW	422	if (dbgfs_register(wdt))
	423	dev_warn(&cldev->dev, "cannot register debugfs\n");
	424
222818c3 TW	425	return 0;
	426
	427	err_disable:
	428	mei_cldev_disable(cldev);
	429
	430	err_out:
	431	kfree(wdt);
	432
	433	return ret;
	434	}
	435
	436	static int mei_wdt_remove(struct mei_cl_device *cldev)
	437	{
	438	struct mei_wdt *wdt = mei_cldev_get_drvdata(cldev);
	439
	440	mei_wdt_unregister(wdt);
	441
	442	mei_cldev_disable(cldev);
	443
c9cf20ee TW	444	dbgfs_unregister(wdt);
c9cf20ee TW	445
222818c3 TW	446	kfree(wdt);
	447
	448	return 0;
	449	}
	450
	451	#define MEI_UUID_WD UUID_LE(0x05B79A6F, 0x4628, 0x4D7F, \
	452	0x89, 0x9D, 0xA9, 0x15, 0x14, 0xCB, 0x32, 0xAB)
	453
	454	static struct mei_cl_device_id mei_wdt_tbl[] = {
	455	{ .uuid = MEI_UUID_WD, .version = 0x1},
	456	/* required last entry */
	457	{ }
	458	};
	459	MODULE_DEVICE_TABLE(mei, mei_wdt_tbl);
	460
	461	static struct mei_cl_driver mei_wdt_driver = {
	462	.id_table = mei_wdt_tbl,
	463	.name = KBUILD_MODNAME,
	464
	465	.probe = mei_wdt_probe,
	466	.remove = mei_wdt_remove,
	467	};
	468
	469	static int __init mei_wdt_init(void)
	470	{
	471	int ret;
	472
	473	ret = mei_cldev_driver_register(&mei_wdt_driver);
	474	if (ret) {
	475	pr_err(KBUILD_MODNAME ": module registration failed\n");
	476	return ret;
	477	}
	478	return 0;
	479	}
	480
	481	static void __exit mei_wdt_exit(void)
	482	{
	483	mei_cldev_driver_unregister(&mei_wdt_driver);
	484	}
	485
	486	module_init(mei_wdt_init);
	487	module_exit(mei_wdt_exit);
	488
	489	MODULE_AUTHOR("Intel Corporation");
	490	MODULE_LICENSE("GPL");
	491	MODULE_DESCRIPTION("Device driver for Intel MEI iAMT watchdog");