[mirror_ubuntu-artful-kernel.git] / drivers / watchdog / uniphier_wdt.c

/*
 * Watchdog driver for the UniPhier watchdog timer
 *
 * (c) Copyright 2014 Panasonic Corporation
 * (c) Copyright 2016 Socionext Inc.
 * All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that 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/bitops.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/watchdog.h>

/* WDT timer setting register */
#define WDTTIMSET			0x3004
#define   WDTTIMSET_PERIOD_MASK		(0xf << 0)
#define   WDTTIMSET_PERIOD_1_SEC	(0x3 << 0)

/* WDT reset selection register */
#define WDTRSTSEL			0x3008
#define   WDTRSTSEL_RSTSEL_MASK		(0x3 << 0)
#define   WDTRSTSEL_RSTSEL_BOTH		(0x0 << 0)
#define   WDTRSTSEL_RSTSEL_IRQ_ONLY	(0x2 << 0)

/* WDT control register */
#define WDTCTRL				0x300c
#define   WDTCTRL_STATUS		BIT(8)
#define   WDTCTRL_CLEAR			BIT(1)
#define   WDTCTRL_ENABLE		BIT(0)

#define SEC_TO_WDTTIMSET_PRD(sec) \
		(ilog2(sec) + WDTTIMSET_PERIOD_1_SEC)

#define WDTST_TIMEOUT			1000 /* usec */

#define WDT_DEFAULT_TIMEOUT		64   /* Default is 64 seconds */
#define WDT_PERIOD_MIN			1
#define WDT_PERIOD_MAX			128

static unsigned int timeout = 0;
static bool nowayout = WATCHDOG_NOWAYOUT;

struct uniphier_wdt_dev {
	struct watchdog_device wdt_dev;
	struct regmap	*regmap;
};

/*
 * UniPhier Watchdog operations
 */
static int uniphier_watchdog_ping(struct watchdog_device *w)
{
	struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
	unsigned int val;
	int ret;

	/* Clear counter */
	ret = regmap_write_bits(wdev->regmap, WDTCTRL,
				WDTCTRL_CLEAR, WDTCTRL_CLEAR);
	if (!ret)
		/*
		 * As SoC specification, after clear counter,
		 * it needs to wait until counter status is 1.
		 */
		ret = regmap_read_poll_timeout(wdev->regmap, WDTCTRL, val,
					       (val & WDTCTRL_STATUS),
					       0, WDTST_TIMEOUT);

	return ret;
}

static int __uniphier_watchdog_start(struct regmap *regmap, unsigned int sec)
{
	unsigned int val;
	int ret;

	ret = regmap_read_poll_timeout(regmap, WDTCTRL, val,
				       !(val & WDTCTRL_STATUS),
				       0, WDTST_TIMEOUT);
	if (ret)
		return ret;

	/* Setup period */
	ret = regmap_write(regmap, WDTTIMSET,
			   SEC_TO_WDTTIMSET_PRD(sec));
	if (ret)
		return ret;

	/* Enable and clear watchdog */
	ret = regmap_write(regmap, WDTCTRL, WDTCTRL_ENABLE | WDTCTRL_CLEAR);
	if (!ret)
		/*
		 * As SoC specification, after clear counter,
		 * it needs to wait until counter status is 1.
		 */
		ret = regmap_read_poll_timeout(regmap, WDTCTRL, val,
					       (val & WDTCTRL_STATUS),
					       0, WDTST_TIMEOUT);

	return ret;
}

static int __uniphier_watchdog_stop(struct regmap *regmap)
{
	/* Disable and stop watchdog */
	return regmap_write_bits(regmap, WDTCTRL, WDTCTRL_ENABLE, 0);
}

static int __uniphier_watchdog_restart(struct regmap *regmap, unsigned int sec)
{
	int ret;

	ret = __uniphier_watchdog_stop(regmap);
	if (ret)
		return ret;

	return __uniphier_watchdog_start(regmap, sec);
}

static int uniphier_watchdog_start(struct watchdog_device *w)
{
	struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
	unsigned int tmp_timeout;

	tmp_timeout = roundup_pow_of_two(w->timeout);

	return __uniphier_watchdog_start(wdev->regmap, tmp_timeout);
}

static int uniphier_watchdog_stop(struct watchdog_device *w)
{
	struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);

	return __uniphier_watchdog_stop(wdev->regmap);
}

static int uniphier_watchdog_set_timeout(struct watchdog_device *w,
					 unsigned int t)
{
	struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
	unsigned int tmp_timeout;
	int ret;

	tmp_timeout = roundup_pow_of_two(t);
	if (tmp_timeout == w->timeout)
		return 0;

	if (watchdog_active(w)) {
		ret = __uniphier_watchdog_restart(wdev->regmap, tmp_timeout);
		if (ret)
			return ret;
	}

	w->timeout = tmp_timeout;

	return 0;
}

/*
 * Kernel Interfaces
 */
static const struct watchdog_info uniphier_wdt_info = {
	.identity	= "uniphier-wdt",
	.options	= WDIOF_SETTIMEOUT |
			  WDIOF_KEEPALIVEPING |
			  WDIOF_MAGICCLOSE |
			  WDIOF_OVERHEAT,
};

static const struct watchdog_ops uniphier_wdt_ops = {
	.owner		= THIS_MODULE,
	.start		= uniphier_watchdog_start,
	.stop		= uniphier_watchdog_stop,
	.ping		= uniphier_watchdog_ping,
	.set_timeout	= uniphier_watchdog_set_timeout,
};

static int uniphier_wdt_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct uniphier_wdt_dev *wdev;
	struct regmap *regmap;
	struct device_node *parent;
	int ret;

	wdev = devm_kzalloc(dev, sizeof(*wdev), GFP_KERNEL);
	if (!wdev)
		return -ENOMEM;

	platform_set_drvdata(pdev, wdev);

	parent = of_get_parent(dev->of_node); /* parent should be syscon node */
	regmap = syscon_node_to_regmap(parent);
	of_node_put(parent);
	if (IS_ERR(regmap))
		return PTR_ERR(regmap);

	wdev->regmap = regmap;
	wdev->wdt_dev.info = &uniphier_wdt_info;
	wdev->wdt_dev.ops = &uniphier_wdt_ops;
	wdev->wdt_dev.max_timeout = WDT_PERIOD_MAX;
	wdev->wdt_dev.min_timeout = WDT_PERIOD_MIN;
	wdev->wdt_dev.parent = dev;

	if (watchdog_init_timeout(&wdev->wdt_dev, timeout, dev) < 0) {
		wdev->wdt_dev.timeout = WDT_DEFAULT_TIMEOUT;
	}
	watchdog_set_nowayout(&wdev->wdt_dev, nowayout);
	watchdog_stop_on_reboot(&wdev->wdt_dev);

	watchdog_set_drvdata(&wdev->wdt_dev, wdev);

	uniphier_watchdog_stop(&wdev->wdt_dev);
	ret = regmap_write(wdev->regmap, WDTRSTSEL, WDTRSTSEL_RSTSEL_BOTH);
	if (ret)
		return ret;

	ret = devm_watchdog_register_device(dev, &wdev->wdt_dev);
	if (ret)
		return ret;

	dev_info(dev, "watchdog driver (timeout=%d sec, nowayout=%d)\n",
		 wdev->wdt_dev.timeout, nowayout);

	return 0;
}

static const struct of_device_id uniphier_wdt_dt_ids[] = {
	{ .compatible = "socionext,uniphier-wdt" },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, uniphier_wdt_dt_ids);

static struct platform_driver uniphier_wdt_driver = {
	.probe		= uniphier_wdt_probe,
	.driver		= {
		.name		= "uniphier-wdt",
		.of_match_table	= uniphier_wdt_dt_ids,
	},
};

module_platform_driver(uniphier_wdt_driver);

module_param(timeout, uint, 0000);
MODULE_PARM_DESC(timeout,
	"Watchdog timeout seconds in power of 2. (0 < timeout < 128, default="
				__MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")");

module_param(nowayout, bool, 0000);
MODULE_PARM_DESC(nowayout,
	"Watchdog cannot be stopped once started (default="
				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

MODULE_AUTHOR("Keiji Hayashibara <hayashibara.keiji@socionext.com>");
MODULE_DESCRIPTION("UniPhier Watchdog Device Driver");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
e7bf0289 KH	1	/*
	2	* Watchdog driver for the UniPhier watchdog timer
	3	*
	4	* (c) Copyright 2014 Panasonic Corporation
	5	* (c) Copyright 2016 Socionext Inc.
	6	* All rights reserved.
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
	11	*
	12	* This program is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	* GNU General Public License for more details.
	16	*/
	17
	18	#include <linux/bitops.h>
	19	#include <linux/mfd/syscon.h>
	20	#include <linux/module.h>
	21	#include <linux/of.h>
	22	#include <linux/platform_device.h>
	23	#include <linux/regmap.h>
	24	#include <linux/watchdog.h>
	25
	26	/* WDT timer setting register */
	27	#define WDTTIMSET 0x3004
	28	#define WDTTIMSET_PERIOD_MASK (0xf << 0)
	29	#define WDTTIMSET_PERIOD_1_SEC (0x3 << 0)
	30
	31	/* WDT reset selection register */
	32	#define WDTRSTSEL 0x3008
	33	#define WDTRSTSEL_RSTSEL_MASK (0x3 << 0)
	34	#define WDTRSTSEL_RSTSEL_BOTH (0x0 << 0)
	35	#define WDTRSTSEL_RSTSEL_IRQ_ONLY (0x2 << 0)
	36
	37	/* WDT control register */
	38	#define WDTCTRL 0x300c
	39	#define WDTCTRL_STATUS BIT(8)
	40	#define WDTCTRL_CLEAR BIT(1)
	41	#define WDTCTRL_ENABLE BIT(0)
	42
	43	#define SEC_TO_WDTTIMSET_PRD(sec) \
	44	(ilog2(sec) + WDTTIMSET_PERIOD_1_SEC)
	45
	46	#define WDTST_TIMEOUT 1000 /* usec */
	47
	48	#define WDT_DEFAULT_TIMEOUT 64 /* Default is 64 seconds */
	49	#define WDT_PERIOD_MIN 1
	50	#define WDT_PERIOD_MAX 128
	51
	52	static unsigned int timeout = 0;
	53	static bool nowayout = WATCHDOG_NOWAYOUT;
	54
	55	struct uniphier_wdt_dev {
	56	struct watchdog_device wdt_dev;
	57	struct regmap *regmap;
	58	};
	59
	60	/*
	61	* UniPhier Watchdog operations
	62	*/
	63	static int uniphier_watchdog_ping(struct watchdog_device *w)
	64	{
65	struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
66	unsigned int val;
67	int ret;
68
69	/* Clear counter */
70	ret = regmap_write_bits(wdev->regmap, WDTCTRL,
71	WDTCTRL_CLEAR, WDTCTRL_CLEAR);
72	if (!ret)
73	/*
74	* As SoC specification, after clear counter,
75	* it needs to wait until counter status is 1.
76	*/
77	ret = regmap_read_poll_timeout(wdev->regmap, WDTCTRL, val,
78	(val & WDTCTRL_STATUS),
79	0, WDTST_TIMEOUT);
80
81	return ret;
82	}
83
84	static int __uniphier_watchdog_start(struct regmap *regmap, unsigned int sec)
85	{
86	unsigned int val;
87	int ret;
88
89	ret = regmap_read_poll_timeout(regmap, WDTCTRL, val,
90	!(val & WDTCTRL_STATUS),
91	0, WDTST_TIMEOUT);
92	if (ret)
93	return ret;
94
95	/* Setup period */
96	ret = regmap_write(regmap, WDTTIMSET,
97	SEC_TO_WDTTIMSET_PRD(sec));
98	if (ret)
99	return ret;
100
101	/* Enable and clear watchdog */
102	ret = regmap_write(regmap, WDTCTRL, WDTCTRL_ENABLE \| WDTCTRL_CLEAR);
103	if (!ret)
104	/*
105	* As SoC specification, after clear counter,
106	* it needs to wait until counter status is 1.
107	*/
108	ret = regmap_read_poll_timeout(regmap, WDTCTRL, val,
109	(val & WDTCTRL_STATUS),
110	0, WDTST_TIMEOUT);
111
112	return ret;
113	}
114
115	static int __uniphier_watchdog_stop(struct regmap *regmap)
116	{
117	/* Disable and stop watchdog */
118	return regmap_write_bits(regmap, WDTCTRL, WDTCTRL_ENABLE, 0);
119	}
120
121	static int __uniphier_watchdog_restart(struct regmap *regmap, unsigned int sec)
122	{
123	int ret;
124
125	ret = __uniphier_watchdog_stop(regmap);
126	if (ret)
127	return ret;
128
129	return __uniphier_watchdog_start(regmap, sec);
130	}
131
132	static int uniphier_watchdog_start(struct watchdog_device *w)
133	{
134	struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
135	unsigned int tmp_timeout;
136
137	tmp_timeout = roundup_pow_of_two(w->timeout);
138
139	return __uniphier_watchdog_start(wdev->regmap, tmp_timeout);
140	}
141
142	static int uniphier_watchdog_stop(struct watchdog_device *w)
143	{
144	struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
145
146	return __uniphier_watchdog_stop(wdev->regmap);
147	}
148
149	static int uniphier_watchdog_set_timeout(struct watchdog_device *w,
150	unsigned int t)
151	{
152	struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
153	unsigned int tmp_timeout;
154	int ret;
155
156	tmp_timeout = roundup_pow_of_two(t);
157	if (tmp_timeout == w->timeout)
158	return 0;
159
160	if (watchdog_active(w)) {
161	ret = __uniphier_watchdog_restart(wdev->regmap, tmp_timeout);
162	if (ret)
163	return ret;
164	}
165
166	w->timeout = tmp_timeout;
167
168	return 0;
169	}
170
171	/*
172	* Kernel Interfaces
173	*/
174	static const struct watchdog_info uniphier_wdt_info = {
175	.identity = "uniphier-wdt",
176	.options = WDIOF_SETTIMEOUT \|
177	WDIOF_KEEPALIVEPING \|
178	WDIOF_MAGICCLOSE \|
179	WDIOF_OVERHEAT,
180	};
181
182	static const struct watchdog_ops uniphier_wdt_ops = {
183	.owner = THIS_MODULE,
184	.start = uniphier_watchdog_start,
185	.stop = uniphier_watchdog_stop,
186	.ping = uniphier_watchdog_ping,
187	.set_timeout = uniphier_watchdog_set_timeout,
188	};
189
190	static int uniphier_wdt_probe(struct platform_device *pdev)
191	{
192	struct device *dev = &pdev->dev;
193	struct uniphier_wdt_dev *wdev;
194	struct regmap *regmap;
195	struct device_node *parent;
196	int ret;
197
198	wdev = devm_kzalloc(dev, sizeof(*wdev), GFP_KERNEL);
199	if (!wdev)
200	return -ENOMEM;
201
202	platform_set_drvdata(pdev, wdev);
203
204	parent = of_get_parent(dev->of_node); /* parent should be syscon node */
205	regmap = syscon_node_to_regmap(parent);
206	of_node_put(parent);
207	if (IS_ERR(regmap))
208	return PTR_ERR(regmap);
209
210	wdev->regmap = regmap;
211	wdev->wdt_dev.info = &uniphier_wdt_info;
212	wdev->wdt_dev.ops = &uniphier_wdt_ops;
213	wdev->wdt_dev.max_timeout = WDT_PERIOD_MAX;
214	wdev->wdt_dev.min_timeout = WDT_PERIOD_MIN;
215	wdev->wdt_dev.parent = dev;
216
217	if (watchdog_init_timeout(&wdev->wdt_dev, timeout, dev) < 0) {
218	wdev->wdt_dev.timeout = WDT_DEFAULT_TIMEOUT;
219	}
220	watchdog_set_nowayout(&wdev->wdt_dev, nowayout);
221	watchdog_stop_on_reboot(&wdev->wdt_dev);
222
223	watchdog_set_drvdata(&wdev->wdt_dev, wdev);
224
225	uniphier_watchdog_stop(&wdev->wdt_dev);
226	ret = regmap_write(wdev->regmap, WDTRSTSEL, WDTRSTSEL_RSTSEL_BOTH);
227	if (ret)
228	return ret;
229
230	ret = devm_watchdog_register_device(dev, &wdev->wdt_dev);
231	if (ret)
232	return ret;
233
234	dev_info(dev, "watchdog driver (timeout=%d sec, nowayout=%d)\n",
235	wdev->wdt_dev.timeout, nowayout);
236
237	return 0;
238	}
239
240	static const struct of_device_id uniphier_wdt_dt_ids[] = {
241	{ .compatible = "socionext,uniphier-wdt" },
242	{ /* sentinel */ }
243	};
244	MODULE_DEVICE_TABLE(of, uniphier_wdt_dt_ids);
245
246	static struct platform_driver uniphier_wdt_driver = {
247	.probe = uniphier_wdt_probe,
248	.driver = {
249	.name = "uniphier-wdt",
250	.of_match_table = uniphier_wdt_dt_ids,
251	},
252	};
253
254	module_platform_driver(uniphier_wdt_driver);
255
256	module_param(timeout, uint, 0000);
257	MODULE_PARM_DESC(timeout,
258	"Watchdog timeout seconds in power of 2. (0 < timeout < 128, default="
259	__MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")");
260
261	module_param(nowayout, bool, 0000);
262	MODULE_PARM_DESC(nowayout,
263	"Watchdog cannot be stopped once started (default="
264	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
265
266	MODULE_AUTHOR("Keiji Hayashibara <hayashibara.keiji@socionext.com>");
267	MODULE_DESCRIPTION("UniPhier Watchdog Device Driver");
268	MODULE_LICENSE("GPL v2");