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22e1b8f6 CC |
1 | /* |
2 | * Meson Watchdog Driver | |
3 | * | |
4 | * Copyright (c) 2014 Carlo Caione | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #include <linux/clk.h> | |
13 | #include <linux/delay.h> | |
14 | #include <linux/err.h> | |
15 | #include <linux/init.h> | |
16 | #include <linux/io.h> | |
17 | #include <linux/kernel.h> | |
18 | #include <linux/module.h> | |
19 | #include <linux/moduleparam.h> | |
22e1b8f6 | 20 | #include <linux/of.h> |
943bf1f6 | 21 | #include <linux/of_device.h> |
22e1b8f6 | 22 | #include <linux/platform_device.h> |
22e1b8f6 CC |
23 | #include <linux/types.h> |
24 | #include <linux/watchdog.h> | |
25 | ||
26 | #define DRV_NAME "meson_wdt" | |
27 | ||
28 | #define MESON_WDT_TC 0x00 | |
22e1b8f6 CC |
29 | #define MESON_WDT_DC_RESET (3 << 24) |
30 | ||
31 | #define MESON_WDT_RESET 0x04 | |
32 | ||
33 | #define MESON_WDT_TIMEOUT 30 | |
34 | #define MESON_WDT_MIN_TIMEOUT 1 | |
22e1b8f6 | 35 | |
943bf1f6 | 36 | #define MESON_SEC_TO_TC(s, c) ((s) * (c)) |
22e1b8f6 CC |
37 | |
38 | static bool nowayout = WATCHDOG_NOWAYOUT; | |
39 | static unsigned int timeout = MESON_WDT_TIMEOUT; | |
40 | ||
943bf1f6 CC |
41 | struct meson_wdt_data { |
42 | unsigned int enable; | |
43 | unsigned int terminal_count_mask; | |
44 | unsigned int count_unit; | |
45 | }; | |
46 | ||
47 | static struct meson_wdt_data meson6_wdt_data = { | |
48 | .enable = BIT(22), | |
49 | .terminal_count_mask = 0x3fffff, | |
50 | .count_unit = 100000, /* 10 us */ | |
51 | }; | |
52 | ||
71388840 CC |
53 | static struct meson_wdt_data meson8b_wdt_data = { |
54 | .enable = BIT(19), | |
55 | .terminal_count_mask = 0xffff, | |
56 | .count_unit = 7812, /* 128 us */ | |
57 | }; | |
58 | ||
22e1b8f6 CC |
59 | struct meson_wdt_dev { |
60 | struct watchdog_device wdt_dev; | |
61 | void __iomem *wdt_base; | |
943bf1f6 | 62 | const struct meson_wdt_data *data; |
22e1b8f6 CC |
63 | }; |
64 | ||
1b6fd59a | 65 | static int meson_wdt_restart(struct watchdog_device *wdt_dev) |
22e1b8f6 | 66 | { |
1b6fd59a | 67 | struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); |
943bf1f6 CC |
68 | u32 tc_reboot = MESON_WDT_DC_RESET; |
69 | ||
70 | tc_reboot |= meson_wdt->data->enable; | |
22e1b8f6 CC |
71 | |
72 | while (1) { | |
73 | writel(tc_reboot, meson_wdt->wdt_base + MESON_WDT_TC); | |
74 | mdelay(5); | |
75 | } | |
76 | ||
1b6fd59a | 77 | return 0; |
22e1b8f6 CC |
78 | } |
79 | ||
80 | static int meson_wdt_ping(struct watchdog_device *wdt_dev) | |
81 | { | |
82 | struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); | |
83 | ||
84 | writel(0, meson_wdt->wdt_base + MESON_WDT_RESET); | |
85 | ||
86 | return 0; | |
87 | } | |
88 | ||
89 | static void meson_wdt_change_timeout(struct watchdog_device *wdt_dev, | |
90 | unsigned int timeout) | |
91 | { | |
92 | struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); | |
93 | u32 reg; | |
94 | ||
95 | reg = readl(meson_wdt->wdt_base + MESON_WDT_TC); | |
943bf1f6 CC |
96 | reg &= ~meson_wdt->data->terminal_count_mask; |
97 | reg |= MESON_SEC_TO_TC(timeout, meson_wdt->data->count_unit); | |
22e1b8f6 CC |
98 | writel(reg, meson_wdt->wdt_base + MESON_WDT_TC); |
99 | } | |
100 | ||
101 | static int meson_wdt_set_timeout(struct watchdog_device *wdt_dev, | |
102 | unsigned int timeout) | |
103 | { | |
104 | wdt_dev->timeout = timeout; | |
105 | ||
106 | meson_wdt_change_timeout(wdt_dev, timeout); | |
107 | meson_wdt_ping(wdt_dev); | |
108 | ||
109 | return 0; | |
110 | } | |
111 | ||
112 | static int meson_wdt_stop(struct watchdog_device *wdt_dev) | |
113 | { | |
114 | struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); | |
115 | u32 reg; | |
116 | ||
117 | reg = readl(meson_wdt->wdt_base + MESON_WDT_TC); | |
943bf1f6 | 118 | reg &= ~meson_wdt->data->enable; |
22e1b8f6 CC |
119 | writel(reg, meson_wdt->wdt_base + MESON_WDT_TC); |
120 | ||
121 | return 0; | |
122 | } | |
123 | ||
124 | static int meson_wdt_start(struct watchdog_device *wdt_dev) | |
125 | { | |
126 | struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); | |
127 | u32 reg; | |
128 | ||
129 | meson_wdt_change_timeout(wdt_dev, meson_wdt->wdt_dev.timeout); | |
130 | meson_wdt_ping(wdt_dev); | |
131 | ||
132 | reg = readl(meson_wdt->wdt_base + MESON_WDT_TC); | |
943bf1f6 | 133 | reg |= meson_wdt->data->enable; |
22e1b8f6 CC |
134 | writel(reg, meson_wdt->wdt_base + MESON_WDT_TC); |
135 | ||
136 | return 0; | |
137 | } | |
138 | ||
139 | static const struct watchdog_info meson_wdt_info = { | |
140 | .identity = DRV_NAME, | |
141 | .options = WDIOF_SETTIMEOUT | | |
142 | WDIOF_KEEPALIVEPING | | |
143 | WDIOF_MAGICCLOSE, | |
144 | }; | |
145 | ||
146 | static const struct watchdog_ops meson_wdt_ops = { | |
147 | .owner = THIS_MODULE, | |
148 | .start = meson_wdt_start, | |
149 | .stop = meson_wdt_stop, | |
150 | .ping = meson_wdt_ping, | |
151 | .set_timeout = meson_wdt_set_timeout, | |
1b6fd59a | 152 | .restart = meson_wdt_restart, |
22e1b8f6 CC |
153 | }; |
154 | ||
943bf1f6 CC |
155 | static const struct of_device_id meson_wdt_dt_ids[] = { |
156 | { .compatible = "amlogic,meson6-wdt", .data = &meson6_wdt_data }, | |
71388840 | 157 | { .compatible = "amlogic,meson8b-wdt", .data = &meson8b_wdt_data }, |
943bf1f6 CC |
158 | { /* sentinel */ } |
159 | }; | |
160 | MODULE_DEVICE_TABLE(of, meson_wdt_dt_ids); | |
161 | ||
22e1b8f6 CC |
162 | static int meson_wdt_probe(struct platform_device *pdev) |
163 | { | |
164 | struct resource *res; | |
165 | struct meson_wdt_dev *meson_wdt; | |
943bf1f6 | 166 | const struct of_device_id *of_id; |
22e1b8f6 CC |
167 | int err; |
168 | ||
169 | meson_wdt = devm_kzalloc(&pdev->dev, sizeof(*meson_wdt), GFP_KERNEL); | |
170 | if (!meson_wdt) | |
171 | return -ENOMEM; | |
172 | ||
173 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
174 | meson_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res); | |
175 | if (IS_ERR(meson_wdt->wdt_base)) | |
176 | return PTR_ERR(meson_wdt->wdt_base); | |
177 | ||
943bf1f6 CC |
178 | of_id = of_match_device(meson_wdt_dt_ids, &pdev->dev); |
179 | if (!of_id) { | |
180 | dev_err(&pdev->dev, "Unable to initialize WDT data\n"); | |
181 | return -ENODEV; | |
182 | } | |
183 | meson_wdt->data = of_id->data; | |
184 | ||
22e1b8f6 CC |
185 | meson_wdt->wdt_dev.parent = &pdev->dev; |
186 | meson_wdt->wdt_dev.info = &meson_wdt_info; | |
187 | meson_wdt->wdt_dev.ops = &meson_wdt_ops; | |
943bf1f6 CC |
188 | meson_wdt->wdt_dev.max_timeout = |
189 | meson_wdt->data->terminal_count_mask / meson_wdt->data->count_unit; | |
22e1b8f6 | 190 | meson_wdt->wdt_dev.min_timeout = MESON_WDT_MIN_TIMEOUT; |
943bf1f6 CC |
191 | meson_wdt->wdt_dev.timeout = min_t(unsigned int, |
192 | MESON_WDT_TIMEOUT, | |
193 | meson_wdt->wdt_dev.max_timeout); | |
22e1b8f6 CC |
194 | |
195 | watchdog_set_drvdata(&meson_wdt->wdt_dev, meson_wdt); | |
196 | ||
197 | watchdog_init_timeout(&meson_wdt->wdt_dev, timeout, &pdev->dev); | |
198 | watchdog_set_nowayout(&meson_wdt->wdt_dev, nowayout); | |
1b6fd59a | 199 | watchdog_set_restart_priority(&meson_wdt->wdt_dev, 128); |
22e1b8f6 CC |
200 | |
201 | meson_wdt_stop(&meson_wdt->wdt_dev); | |
202 | ||
203 | err = watchdog_register_device(&meson_wdt->wdt_dev); | |
204 | if (err) | |
205 | return err; | |
206 | ||
207 | platform_set_drvdata(pdev, meson_wdt); | |
208 | ||
22e1b8f6 CC |
209 | dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)", |
210 | meson_wdt->wdt_dev.timeout, nowayout); | |
211 | ||
212 | return 0; | |
213 | } | |
214 | ||
215 | static int meson_wdt_remove(struct platform_device *pdev) | |
216 | { | |
217 | struct meson_wdt_dev *meson_wdt = platform_get_drvdata(pdev); | |
218 | ||
22e1b8f6 CC |
219 | watchdog_unregister_device(&meson_wdt->wdt_dev); |
220 | ||
221 | return 0; | |
222 | } | |
223 | ||
224 | static void meson_wdt_shutdown(struct platform_device *pdev) | |
225 | { | |
226 | struct meson_wdt_dev *meson_wdt = platform_get_drvdata(pdev); | |
227 | ||
228 | meson_wdt_stop(&meson_wdt->wdt_dev); | |
229 | } | |
230 | ||
22e1b8f6 CC |
231 | static struct platform_driver meson_wdt_driver = { |
232 | .probe = meson_wdt_probe, | |
233 | .remove = meson_wdt_remove, | |
234 | .shutdown = meson_wdt_shutdown, | |
235 | .driver = { | |
22e1b8f6 CC |
236 | .name = DRV_NAME, |
237 | .of_match_table = meson_wdt_dt_ids, | |
238 | }, | |
239 | }; | |
240 | ||
241 | module_platform_driver(meson_wdt_driver); | |
242 | ||
243 | module_param(timeout, uint, 0); | |
244 | MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds"); | |
245 | ||
246 | module_param(nowayout, bool, 0); | |
247 | MODULE_PARM_DESC(nowayout, | |
248 | "Watchdog cannot be stopped once started (default=" | |
249 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
250 | ||
251 | MODULE_LICENSE("GPL"); | |
252 | MODULE_AUTHOR("Carlo Caione <carlo@caione.org>"); | |
253 | MODULE_DESCRIPTION("Meson Watchdog Timer Driver"); |