summaryrefslogtreecommitdiffstats
path: root/drivers/watchdog/st_lpc_wdt.c
blob: f32be155212adfea313f3c45716749199af2296d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
/*
 * ST's LPC Watchdog
 *
 * Copyright (C) 2014 STMicroelectronics -- All Rights Reserved
 *
 * Author: David Paris <david.paris@st.com> for STMicroelectronics
 *         Lee Jones <lee.jones@linaro.org> for STMicroelectronics
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */

#include <linux/clk.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/watchdog.h>

#include <dt-bindings/mfd/st-lpc.h>

/* Low Power Alarm */
#define LPC_LPA_LSB_OFF			0x410
#define LPC_LPA_START_OFF		0x418

/* LPC as WDT */
#define LPC_WDT_OFF			0x510

static struct watchdog_device st_wdog_dev;

struct st_wdog_syscfg {
	unsigned int reset_type_reg;
	unsigned int reset_type_mask;
	unsigned int enable_reg;
	unsigned int enable_mask;
};

struct st_wdog {
	void __iomem *base;
	struct device *dev;
	struct regmap *regmap;
	struct st_wdog_syscfg *syscfg;
	struct clk *clk;
	unsigned long clkrate;
	bool warm_reset;
};

static struct st_wdog_syscfg stid127_syscfg = {
	.reset_type_reg		= 0x004,
	.reset_type_mask	= BIT(2),
	.enable_reg		= 0x000,
	.enable_mask		= BIT(2),
};

static struct st_wdog_syscfg stih415_syscfg = {
	.reset_type_reg		= 0x0B8,
	.reset_type_mask	= BIT(6),
	.enable_reg		= 0x0B4,
	.enable_mask		= BIT(7),
};

static struct st_wdog_syscfg stih416_syscfg = {
	.reset_type_reg		= 0x88C,
	.reset_type_mask	= BIT(6),
	.enable_reg		= 0x888,
	.enable_mask		= BIT(7),
};

static struct st_wdog_syscfg stih407_syscfg = {
	.enable_reg		= 0x204,
	.enable_mask		= BIT(19),
};

static const struct of_device_id st_wdog_match[] = {
	{
		.compatible = "st,stih407-lpc",
		.data = &stih407_syscfg,
	},
	{
		.compatible = "st,stih416-lpc",
		.data = &stih416_syscfg,
	},
	{
		.compatible = "st,stih415-lpc",
		.data = &stih415_syscfg,
	},
	{
		.compatible = "st,stid127-lpc",
		.data = &stid127_syscfg,
	},
	{},
};
MODULE_DEVICE_TABLE(of, st_wdog_match);

static void st_wdog_setup(struct st_wdog *st_wdog, bool enable)
{
	/* Type of watchdog reset - 0: Cold 1: Warm */
	if (st_wdog->syscfg->reset_type_reg)
		regmap_update_bits(st_wdog->regmap,
				   st_wdog->syscfg->reset_type_reg,
				   st_wdog->syscfg->reset_type_mask,
				   st_wdog->warm_reset);

	/* Mask/unmask watchdog reset */
	regmap_update_bits(st_wdog->regmap,
			   st_wdog->syscfg->enable_reg,
			   st_wdog->syscfg->enable_mask,
			   enable ? 0 : st_wdog->syscfg->enable_mask);
}

static void st_wdog_load_timer(struct st_wdog *st_wdog, unsigned int timeout)
{
	unsigned long clkrate = st_wdog->clkrate;

	writel_relaxed(timeout * clkrate, st_wdog->base + LPC_LPA_LSB_OFF);
	writel_relaxed(1, st_wdog->base + LPC_LPA_START_OFF);
}

static int st_wdog_start(struct watchdog_device *wdd)
{
	struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);

	writel_relaxed(1, st_wdog->base + LPC_WDT_OFF);

	return 0;
}

static int st_wdog_stop(struct watchdog_device *wdd)
{
	struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);

	writel_relaxed(0, st_wdog->base + LPC_WDT_OFF);

	return 0;
}

static int st_wdog_set_timeout(struct watchdog_device *wdd,
			       unsigned int timeout)
{
	struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);

	wdd->timeout = timeout;
	st_wdog_load_timer(st_wdog, timeout);

	return 0;
}

static int st_wdog_keepalive(struct watchdog_device *wdd)
{
	struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);

	st_wdog_load_timer(st_wdog, wdd->timeout);

	return 0;
}

static const struct watchdog_info st_wdog_info = {
	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
	.identity = "ST LPC WDT",
};

static const struct watchdog_ops st_wdog_ops = {
	.owner		= THIS_MODULE,
	.start		= st_wdog_start,
	.stop		= st_wdog_stop,
	.ping		= st_wdog_keepalive,
	.set_timeout	= st_wdog_set_timeout,
};

static struct watchdog_device st_wdog_dev = {
	.info		= &st_wdog_info,
	.ops		= &st_wdog_ops,
};

static int st_wdog_probe(struct platform_device *pdev)
{
	const struct of_device_id *match;
	struct device_node *np = pdev->dev.of_node;
	struct st_wdog *st_wdog;
	struct regmap *regmap;
	struct resource *res;
	struct clk *clk;
	void __iomem *base;
	uint32_t mode;
	int ret;

	ret = of_property_read_u32(np, "st,lpc-mode", &mode);
	if (ret) {
		dev_err(&pdev->dev, "An LPC mode must be provided\n");
		return -EINVAL;
	}

	/* LPC can either run in RTC or WDT mode */
	if (mode != ST_LPC_MODE_WDT)
		return -ENODEV;

	st_wdog = devm_kzalloc(&pdev->dev, sizeof(*st_wdog), GFP_KERNEL);
	if (!st_wdog)
		return -ENOMEM;

	match = of_match_device(st_wdog_match, &pdev->dev);
	if (!match) {
		dev_err(&pdev->dev, "Couldn't match device\n");
		return -ENODEV;
	}
	st_wdog->syscfg	= (struct st_wdog_syscfg *)match->data;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(base))
		return PTR_ERR(base);

	regmap = syscon_regmap_lookup_by_phandle(np, "st,syscfg");
	if (IS_ERR(regmap)) {
		dev_err(&pdev->dev, "No syscfg phandle specified\n");
		return PTR_ERR(regmap);
	}

	clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(clk)) {
		dev_err(&pdev->dev, "Unable to request clock\n");
		return PTR_ERR(clk);
	}

	st_wdog->dev		= &pdev->dev;
	st_wdog->base		= base;
	st_wdog->clk		= clk;
	st_wdog->regmap		= regmap;
	st_wdog->warm_reset	= of_property_read_bool(np, "st,warm_reset");
	st_wdog->clkrate	= clk_get_rate(st_wdog->clk);

	if (!st_wdog->clkrate) {
		dev_err(&pdev->dev, "Unable to fetch clock rate\n");
		return -EINVAL;
	}
	st_wdog_dev.max_timeout = 0xFFFFFFFF / st_wdog->clkrate;

	ret = clk_prepare_enable(clk);
	if (ret) {
		dev_err(&pdev->dev, "Unable to enable clock\n");
		return ret;
	}

	watchdog_set_drvdata(&st_wdog_dev, st_wdog);
	watchdog_set_nowayout(&st_wdog_dev, WATCHDOG_NOWAYOUT);

	/* Init Watchdog timeout with value in DT */
	ret = watchdog_init_timeout(&st_wdog_dev, 0, &pdev->dev);
	if (ret) {
		dev_err(&pdev->dev, "Unable to initialise watchdog timeout\n");
		clk_disable_unprepare(clk);
		return ret;
	}

	ret = watchdog_register_device(&st_wdog_dev);
	if (ret) {
		dev_err(&pdev->dev, "Unable to register watchdog\n");
		clk_disable_unprepare(clk);
		return ret;
	}

	st_wdog_setup(st_wdog, true);

	dev_info(&pdev->dev, "LPC Watchdog driver registered, reset type is %s",
		 st_wdog->warm_reset ? "warm" : "cold");

	return ret;
}

static int st_wdog_remove(struct platform_device *pdev)
{
	struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev);

	st_wdog_setup(st_wdog, false);
	watchdog_unregister_device(&st_wdog_dev);
	clk_disable_unprepare(st_wdog->clk);

	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int st_wdog_suspend(struct device *dev)
{
	struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev);

	if (watchdog_active(&st_wdog_dev))
		st_wdog_stop(&st_wdog_dev);

	st_wdog_setup(st_wdog, false);

	clk_disable(st_wdog->clk);

	return 0;
}

static int st_wdog_resume(struct device *dev)
{
	struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev);
	int ret;

	ret = clk_enable(st_wdog->clk);
	if (ret) {
		dev_err(dev, "Unable to re-enable clock\n");
		watchdog_unregister_device(&st_wdog_dev);
		clk_unprepare(st_wdog->clk);
		return ret;
	}

	st_wdog_setup(st_wdog, true);

	if (watchdog_active(&st_wdog_dev)) {
		st_wdog_load_timer(st_wdog, st_wdog_dev.timeout);
		st_wdog_start(&st_wdog_dev);
	}

	return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(st_wdog_pm_ops,
			 st_wdog_suspend,
			 st_wdog_resume);

static struct platform_driver st_wdog_driver = {
	.driver	= {
		.name = "st-lpc-wdt",
		.pm = &st_wdog_pm_ops,
		.of_match_table = st_wdog_match,
	},
	.probe = st_wdog_probe,
	.remove = st_wdog_remove,
};
module_platform_driver(st_wdog_driver);

MODULE_AUTHOR("David Paris <david.paris@st.com>");
MODULE_DESCRIPTION("ST LPC Watchdog Driver");
MODULE_LICENSE("GPL");
OpenPOWER on IntegriCloud