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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 | ||
4d8b229d GR |
65 | static int meson_wdt_restart(struct watchdog_device *wdt_dev, |
66 | unsigned long action, void *data) | |
22e1b8f6 | 67 | { |
1b6fd59a | 68 | struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); |
943bf1f6 CC |
69 | u32 tc_reboot = MESON_WDT_DC_RESET; |
70 | ||
71 | tc_reboot |= meson_wdt->data->enable; | |
22e1b8f6 CC |
72 | |
73 | while (1) { | |
74 | writel(tc_reboot, meson_wdt->wdt_base + MESON_WDT_TC); | |
75 | mdelay(5); | |
76 | } | |
77 | ||
1b6fd59a | 78 | return 0; |
22e1b8f6 CC |
79 | } |
80 | ||
81 | static int meson_wdt_ping(struct watchdog_device *wdt_dev) | |
82 | { | |
83 | struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); | |
84 | ||
85 | writel(0, meson_wdt->wdt_base + MESON_WDT_RESET); | |
86 | ||
87 | return 0; | |
88 | } | |
89 | ||
90 | static void meson_wdt_change_timeout(struct watchdog_device *wdt_dev, | |
91 | unsigned int timeout) | |
92 | { | |
93 | struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); | |
94 | u32 reg; | |
95 | ||
96 | reg = readl(meson_wdt->wdt_base + MESON_WDT_TC); | |
943bf1f6 CC |
97 | reg &= ~meson_wdt->data->terminal_count_mask; |
98 | reg |= MESON_SEC_TO_TC(timeout, meson_wdt->data->count_unit); | |
22e1b8f6 CC |
99 | writel(reg, meson_wdt->wdt_base + MESON_WDT_TC); |
100 | } | |
101 | ||
102 | static int meson_wdt_set_timeout(struct watchdog_device *wdt_dev, | |
103 | unsigned int timeout) | |
104 | { | |
105 | wdt_dev->timeout = timeout; | |
106 | ||
107 | meson_wdt_change_timeout(wdt_dev, timeout); | |
108 | meson_wdt_ping(wdt_dev); | |
109 | ||
110 | return 0; | |
111 | } | |
112 | ||
113 | static int meson_wdt_stop(struct watchdog_device *wdt_dev) | |
114 | { | |
115 | struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); | |
116 | u32 reg; | |
117 | ||
118 | reg = readl(meson_wdt->wdt_base + MESON_WDT_TC); | |
943bf1f6 | 119 | reg &= ~meson_wdt->data->enable; |
22e1b8f6 CC |
120 | writel(reg, meson_wdt->wdt_base + MESON_WDT_TC); |
121 | ||
122 | return 0; | |
123 | } | |
124 | ||
125 | static int meson_wdt_start(struct watchdog_device *wdt_dev) | |
126 | { | |
127 | struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); | |
128 | u32 reg; | |
129 | ||
130 | meson_wdt_change_timeout(wdt_dev, meson_wdt->wdt_dev.timeout); | |
131 | meson_wdt_ping(wdt_dev); | |
132 | ||
133 | reg = readl(meson_wdt->wdt_base + MESON_WDT_TC); | |
943bf1f6 | 134 | reg |= meson_wdt->data->enable; |
22e1b8f6 CC |
135 | writel(reg, meson_wdt->wdt_base + MESON_WDT_TC); |
136 | ||
137 | return 0; | |
138 | } | |
139 | ||
140 | static const struct watchdog_info meson_wdt_info = { | |
141 | .identity = DRV_NAME, | |
142 | .options = WDIOF_SETTIMEOUT | | |
143 | WDIOF_KEEPALIVEPING | | |
144 | WDIOF_MAGICCLOSE, | |
145 | }; | |
146 | ||
147 | static const struct watchdog_ops meson_wdt_ops = { | |
148 | .owner = THIS_MODULE, | |
149 | .start = meson_wdt_start, | |
150 | .stop = meson_wdt_stop, | |
151 | .ping = meson_wdt_ping, | |
152 | .set_timeout = meson_wdt_set_timeout, | |
1b6fd59a | 153 | .restart = meson_wdt_restart, |
22e1b8f6 CC |
154 | }; |
155 | ||
943bf1f6 CC |
156 | static const struct of_device_id meson_wdt_dt_ids[] = { |
157 | { .compatible = "amlogic,meson6-wdt", .data = &meson6_wdt_data }, | |
71388840 | 158 | { .compatible = "amlogic,meson8b-wdt", .data = &meson8b_wdt_data }, |
943bf1f6 CC |
159 | { /* sentinel */ } |
160 | }; | |
161 | MODULE_DEVICE_TABLE(of, meson_wdt_dt_ids); | |
162 | ||
22e1b8f6 CC |
163 | static int meson_wdt_probe(struct platform_device *pdev) |
164 | { | |
165 | struct resource *res; | |
166 | struct meson_wdt_dev *meson_wdt; | |
943bf1f6 | 167 | const struct of_device_id *of_id; |
22e1b8f6 CC |
168 | int err; |
169 | ||
170 | meson_wdt = devm_kzalloc(&pdev->dev, sizeof(*meson_wdt), GFP_KERNEL); | |
171 | if (!meson_wdt) | |
172 | return -ENOMEM; | |
173 | ||
174 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
175 | meson_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res); | |
176 | if (IS_ERR(meson_wdt->wdt_base)) | |
177 | return PTR_ERR(meson_wdt->wdt_base); | |
178 | ||
943bf1f6 CC |
179 | of_id = of_match_device(meson_wdt_dt_ids, &pdev->dev); |
180 | if (!of_id) { | |
181 | dev_err(&pdev->dev, "Unable to initialize WDT data\n"); | |
182 | return -ENODEV; | |
183 | } | |
184 | meson_wdt->data = of_id->data; | |
185 | ||
22e1b8f6 CC |
186 | meson_wdt->wdt_dev.parent = &pdev->dev; |
187 | meson_wdt->wdt_dev.info = &meson_wdt_info; | |
188 | meson_wdt->wdt_dev.ops = &meson_wdt_ops; | |
943bf1f6 CC |
189 | meson_wdt->wdt_dev.max_timeout = |
190 | meson_wdt->data->terminal_count_mask / meson_wdt->data->count_unit; | |
22e1b8f6 | 191 | meson_wdt->wdt_dev.min_timeout = MESON_WDT_MIN_TIMEOUT; |
943bf1f6 CC |
192 | meson_wdt->wdt_dev.timeout = min_t(unsigned int, |
193 | MESON_WDT_TIMEOUT, | |
194 | meson_wdt->wdt_dev.max_timeout); | |
22e1b8f6 CC |
195 | |
196 | watchdog_set_drvdata(&meson_wdt->wdt_dev, meson_wdt); | |
197 | ||
198 | watchdog_init_timeout(&meson_wdt->wdt_dev, timeout, &pdev->dev); | |
199 | watchdog_set_nowayout(&meson_wdt->wdt_dev, nowayout); | |
1b6fd59a | 200 | watchdog_set_restart_priority(&meson_wdt->wdt_dev, 128); |
22e1b8f6 CC |
201 | |
202 | meson_wdt_stop(&meson_wdt->wdt_dev); | |
203 | ||
204 | err = watchdog_register_device(&meson_wdt->wdt_dev); | |
205 | if (err) | |
206 | return err; | |
207 | ||
208 | platform_set_drvdata(pdev, meson_wdt); | |
209 | ||
22e1b8f6 CC |
210 | dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)", |
211 | meson_wdt->wdt_dev.timeout, nowayout); | |
212 | ||
213 | return 0; | |
214 | } | |
215 | ||
216 | static int meson_wdt_remove(struct platform_device *pdev) | |
217 | { | |
218 | struct meson_wdt_dev *meson_wdt = platform_get_drvdata(pdev); | |
219 | ||
22e1b8f6 CC |
220 | watchdog_unregister_device(&meson_wdt->wdt_dev); |
221 | ||
222 | return 0; | |
223 | } | |
224 | ||
225 | static void meson_wdt_shutdown(struct platform_device *pdev) | |
226 | { | |
227 | struct meson_wdt_dev *meson_wdt = platform_get_drvdata(pdev); | |
228 | ||
229 | meson_wdt_stop(&meson_wdt->wdt_dev); | |
230 | } | |
231 | ||
22e1b8f6 CC |
232 | static struct platform_driver meson_wdt_driver = { |
233 | .probe = meson_wdt_probe, | |
234 | .remove = meson_wdt_remove, | |
235 | .shutdown = meson_wdt_shutdown, | |
236 | .driver = { | |
22e1b8f6 CC |
237 | .name = DRV_NAME, |
238 | .of_match_table = meson_wdt_dt_ids, | |
239 | }, | |
240 | }; | |
241 | ||
242 | module_platform_driver(meson_wdt_driver); | |
243 | ||
244 | module_param(timeout, uint, 0); | |
245 | MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds"); | |
246 | ||
247 | module_param(nowayout, bool, 0); | |
248 | MODULE_PARM_DESC(nowayout, | |
249 | "Watchdog cannot be stopped once started (default=" | |
250 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
251 | ||
252 | MODULE_LICENSE("GPL"); | |
253 | MODULE_AUTHOR("Carlo Caione <carlo@caione.org>"); | |
254 | MODULE_DESCRIPTION("Meson Watchdog Timer Driver"); |