summaryrefslogtreecommitdiffstats
path: root/drivers/watchdog/atlas7_wdt.c
blob: 79337d2a8a8e226a8ff08d347e8b858490b47aa2 (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
/*
 * Watchdog driver for CSR Atlas7
 *
 * Copyright (c) 2015 Cambridge Silicon Radio Limited, a CSR plc group company.
 *
 * Licensed under GPLv2.
 */

#include <linux/clk.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>

#define ATLAS7_TIMER_WDT_INDEX		5
#define ATLAS7_WDT_DEFAULT_TIMEOUT	20

#define ATLAS7_WDT_CNT_CTRL	(0 + 4 * ATLAS7_TIMER_WDT_INDEX)
#define ATLAS7_WDT_CNT_MATCH	(0x18 + 4 * ATLAS7_TIMER_WDT_INDEX)
#define ATLAS7_WDT_CNT		(0x48 +  4 * ATLAS7_TIMER_WDT_INDEX)
#define ATLAS7_WDT_CNT_EN	(BIT(0) | BIT(1))
#define ATLAS7_WDT_EN		0x64

static unsigned int timeout = ATLAS7_WDT_DEFAULT_TIMEOUT;
static bool nowayout = WATCHDOG_NOWAYOUT;

module_param(timeout, uint, 0);
module_param(nowayout, bool, 0);

MODULE_PARM_DESC(timeout, "Default watchdog timeout (in seconds)");
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
			__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

struct atlas7_wdog {
	struct device *dev;
	void __iomem *base;
	unsigned long tick_rate;
	struct clk *clk;
};

static unsigned int atlas7_wdt_gettimeleft(struct watchdog_device *wdd)
{
	struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
	u32 counter, match, delta;

	counter = readl(wdt->base + ATLAS7_WDT_CNT);
	match = readl(wdt->base + ATLAS7_WDT_CNT_MATCH);
	delta = match - counter;

	return  delta / wdt->tick_rate;
}

static int atlas7_wdt_ping(struct watchdog_device *wdd)
{
	struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
	u32 counter, match, delta;

	counter = readl(wdt->base + ATLAS7_WDT_CNT);
	delta = wdd->timeout * wdt->tick_rate;
	match = counter + delta;

	writel(match, wdt->base + ATLAS7_WDT_CNT_MATCH);

	return 0;
}

static int atlas7_wdt_enable(struct watchdog_device *wdd)
{
	struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);

	atlas7_wdt_ping(wdd);

	writel(readl(wdt->base + ATLAS7_WDT_CNT_CTRL) | ATLAS7_WDT_CNT_EN,
	      wdt->base + ATLAS7_WDT_CNT_CTRL);
	writel(1, wdt->base + ATLAS7_WDT_EN);

	return 0;
}

static int atlas7_wdt_disable(struct watchdog_device *wdd)
{
	struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);

	writel(0, wdt->base + ATLAS7_WDT_EN);
	writel(readl(wdt->base + ATLAS7_WDT_CNT_CTRL) & ~ATLAS7_WDT_CNT_EN,
	      wdt->base + ATLAS7_WDT_CNT_CTRL);

	return 0;
}

static int atlas7_wdt_settimeout(struct watchdog_device *wdd, unsigned int to)
{
	wdd->timeout = to;

	return 0;
}

#define OPTIONS (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE)

static const struct watchdog_info atlas7_wdt_ident = {
	.options = OPTIONS,
	.firmware_version = 0,
	.identity = "atlas7 Watchdog",
};

static const struct watchdog_ops atlas7_wdt_ops = {
	.owner = THIS_MODULE,
	.start = atlas7_wdt_enable,
	.stop = atlas7_wdt_disable,
	.get_timeleft = atlas7_wdt_gettimeleft,
	.ping = atlas7_wdt_ping,
	.set_timeout = atlas7_wdt_settimeout,
};

static struct watchdog_device atlas7_wdd = {
	.info = &atlas7_wdt_ident,
	.ops = &atlas7_wdt_ops,
	.timeout = ATLAS7_WDT_DEFAULT_TIMEOUT,
};

static const struct of_device_id atlas7_wdt_ids[] = {
	{ .compatible = "sirf,atlas7-tick"},
	{}
};

static void atlas7_clk_disable_unprepare(void *data)
{
	clk_disable_unprepare(data);
}

static int atlas7_wdt_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct atlas7_wdog *wdt;
	struct clk *clk;
	int ret;

	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
	if (!wdt)
		return -ENOMEM;
	wdt->base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(wdt->base))
		return PTR_ERR(wdt->base);

	clk = devm_clk_get(dev, NULL);
	if (IS_ERR(clk))
		return PTR_ERR(clk);
	ret = clk_prepare_enable(clk);
	if (ret) {
		dev_err(dev, "clk enable failed\n");
		return ret;
	}
	ret = devm_add_action_or_reset(dev, atlas7_clk_disable_unprepare, clk);
	if (ret)
		return ret;

	/* disable watchdog hardware */
	writel(0, wdt->base + ATLAS7_WDT_CNT_CTRL);

	wdt->tick_rate = clk_get_rate(clk);
	if (!wdt->tick_rate)
		return -EINVAL;

	wdt->clk = clk;
	atlas7_wdd.min_timeout = 1;
	atlas7_wdd.max_timeout = UINT_MAX / wdt->tick_rate;

	watchdog_init_timeout(&atlas7_wdd, 0, dev);
	watchdog_set_nowayout(&atlas7_wdd, nowayout);

	watchdog_set_drvdata(&atlas7_wdd, wdt);
	platform_set_drvdata(pdev, &atlas7_wdd);

	watchdog_stop_on_reboot(&atlas7_wdd);
	watchdog_stop_on_unregister(&atlas7_wdd);
	return devm_watchdog_register_device(dev, &atlas7_wdd);
}

static int __maybe_unused atlas7_wdt_suspend(struct device *dev)
{
	/*
	 * NOTE:timer controller registers settings are saved
	 * and restored back by the timer-atlas7.c
	 */
	return 0;
}

static int __maybe_unused atlas7_wdt_resume(struct device *dev)
{
	struct watchdog_device *wdd = dev_get_drvdata(dev);

	/*
	 * NOTE: Since timer controller registers settings are saved
	 * and restored back by the timer-atlas7.c, so we need not
	 * update WD settings except refreshing timeout.
	 */
	atlas7_wdt_ping(wdd);

	return 0;
}

static SIMPLE_DEV_PM_OPS(atlas7_wdt_pm_ops,
		atlas7_wdt_suspend, atlas7_wdt_resume);

MODULE_DEVICE_TABLE(of, atlas7_wdt_ids);

static struct platform_driver atlas7_wdt_driver = {
	.driver = {
		.name = "atlas7-wdt",
		.pm = &atlas7_wdt_pm_ops,
		.of_match_table	= atlas7_wdt_ids,
	},
	.probe = atlas7_wdt_probe,
};
module_platform_driver(atlas7_wdt_driver);

MODULE_DESCRIPTION("CSRatlas7 watchdog driver");
MODULE_AUTHOR("Guo Zeng <Guo.Zeng@csr.com>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:atlas7-wdt");