1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * Meson Watchdog Driver |
4 | * |
5 | * Copyright (c) 2014 Carlo Caione |
6 | */ |
7 | |
8 | #include <linux/clk.h> |
9 | #include <linux/delay.h> |
10 | #include <linux/err.h> |
11 | #include <linux/init.h> |
12 | #include <linux/io.h> |
13 | #include <linux/kernel.h> |
14 | #include <linux/mod_devicetable.h> |
15 | #include <linux/module.h> |
16 | #include <linux/moduleparam.h> |
17 | #include <linux/platform_device.h> |
18 | #include <linux/property.h> |
19 | #include <linux/types.h> |
20 | #include <linux/watchdog.h> |
21 | |
22 | #define DRV_NAME "meson_wdt" |
23 | |
24 | #define MESON_WDT_TC 0x00 |
25 | #define MESON_WDT_DC_RESET (3 << 24) |
26 | |
27 | #define MESON_WDT_RESET 0x04 |
28 | |
29 | #define MESON_WDT_TIMEOUT 30 |
30 | #define MESON_WDT_MIN_TIMEOUT 1 |
31 | |
32 | #define MESON_SEC_TO_TC(s, c) ((s) * (c)) |
33 | |
34 | static bool nowayout = WATCHDOG_NOWAYOUT; |
35 | static unsigned int timeout; |
36 | |
37 | struct meson_wdt_data { |
38 | unsigned int enable; |
39 | unsigned int terminal_count_mask; |
40 | unsigned int count_unit; |
41 | }; |
42 | |
43 | static struct meson_wdt_data meson6_wdt_data = { |
44 | .enable = BIT(22), |
45 | .terminal_count_mask = 0x3fffff, |
46 | .count_unit = 100000, /* 10 us */ |
47 | }; |
48 | |
49 | static struct meson_wdt_data meson8b_wdt_data = { |
50 | .enable = BIT(19), |
51 | .terminal_count_mask = 0xffff, |
52 | .count_unit = 7812, /* 128 us */ |
53 | }; |
54 | |
55 | struct meson_wdt_dev { |
56 | struct watchdog_device wdt_dev; |
57 | void __iomem *wdt_base; |
58 | const struct meson_wdt_data *data; |
59 | }; |
60 | |
61 | static int meson_wdt_restart(struct watchdog_device *wdt_dev, |
62 | unsigned long action, void *data) |
63 | { |
64 | struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdd: wdt_dev); |
65 | u32 tc_reboot = MESON_WDT_DC_RESET; |
66 | |
67 | tc_reboot |= meson_wdt->data->enable; |
68 | |
69 | while (1) { |
70 | writel(val: tc_reboot, addr: meson_wdt->wdt_base + MESON_WDT_TC); |
71 | mdelay(5); |
72 | } |
73 | |
74 | return 0; |
75 | } |
76 | |
77 | static int meson_wdt_ping(struct watchdog_device *wdt_dev) |
78 | { |
79 | struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdd: wdt_dev); |
80 | |
81 | writel(val: 0, addr: meson_wdt->wdt_base + MESON_WDT_RESET); |
82 | |
83 | return 0; |
84 | } |
85 | |
86 | static void meson_wdt_change_timeout(struct watchdog_device *wdt_dev, |
87 | unsigned int timeout) |
88 | { |
89 | struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdd: wdt_dev); |
90 | u32 reg; |
91 | |
92 | reg = readl(addr: meson_wdt->wdt_base + MESON_WDT_TC); |
93 | reg &= ~meson_wdt->data->terminal_count_mask; |
94 | reg |= MESON_SEC_TO_TC(timeout, meson_wdt->data->count_unit); |
95 | writel(val: reg, addr: meson_wdt->wdt_base + MESON_WDT_TC); |
96 | } |
97 | |
98 | static int meson_wdt_set_timeout(struct watchdog_device *wdt_dev, |
99 | unsigned int timeout) |
100 | { |
101 | wdt_dev->timeout = timeout; |
102 | |
103 | meson_wdt_change_timeout(wdt_dev, timeout); |
104 | meson_wdt_ping(wdt_dev); |
105 | |
106 | return 0; |
107 | } |
108 | |
109 | static int meson_wdt_stop(struct watchdog_device *wdt_dev) |
110 | { |
111 | struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdd: wdt_dev); |
112 | u32 reg; |
113 | |
114 | reg = readl(addr: meson_wdt->wdt_base + MESON_WDT_TC); |
115 | reg &= ~meson_wdt->data->enable; |
116 | writel(val: reg, addr: meson_wdt->wdt_base + MESON_WDT_TC); |
117 | |
118 | return 0; |
119 | } |
120 | |
121 | static int meson_wdt_start(struct watchdog_device *wdt_dev) |
122 | { |
123 | struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdd: wdt_dev); |
124 | u32 reg; |
125 | |
126 | meson_wdt_change_timeout(wdt_dev, timeout: meson_wdt->wdt_dev.timeout); |
127 | meson_wdt_ping(wdt_dev); |
128 | |
129 | reg = readl(addr: meson_wdt->wdt_base + MESON_WDT_TC); |
130 | reg |= meson_wdt->data->enable; |
131 | writel(val: reg, addr: meson_wdt->wdt_base + MESON_WDT_TC); |
132 | |
133 | return 0; |
134 | } |
135 | |
136 | static const struct watchdog_info meson_wdt_info = { |
137 | .identity = DRV_NAME, |
138 | .options = WDIOF_SETTIMEOUT | |
139 | WDIOF_KEEPALIVEPING | |
140 | WDIOF_MAGICCLOSE, |
141 | }; |
142 | |
143 | static const struct watchdog_ops meson_wdt_ops = { |
144 | .owner = THIS_MODULE, |
145 | .start = meson_wdt_start, |
146 | .stop = meson_wdt_stop, |
147 | .ping = meson_wdt_ping, |
148 | .set_timeout = meson_wdt_set_timeout, |
149 | .restart = meson_wdt_restart, |
150 | }; |
151 | |
152 | static const struct of_device_id meson_wdt_dt_ids[] = { |
153 | { .compatible = "amlogic,meson6-wdt" , .data = &meson6_wdt_data }, |
154 | { .compatible = "amlogic,meson8-wdt" , .data = &meson6_wdt_data }, |
155 | { .compatible = "amlogic,meson8b-wdt" , .data = &meson8b_wdt_data }, |
156 | { .compatible = "amlogic,meson8m2-wdt" , .data = &meson8b_wdt_data }, |
157 | { /* sentinel */ } |
158 | }; |
159 | MODULE_DEVICE_TABLE(of, meson_wdt_dt_ids); |
160 | |
161 | static int meson_wdt_probe(struct platform_device *pdev) |
162 | { |
163 | struct device *dev = &pdev->dev; |
164 | struct meson_wdt_dev *meson_wdt; |
165 | int err; |
166 | |
167 | meson_wdt = devm_kzalloc(dev, size: sizeof(*meson_wdt), GFP_KERNEL); |
168 | if (!meson_wdt) |
169 | return -ENOMEM; |
170 | |
171 | meson_wdt->wdt_base = devm_platform_ioremap_resource(pdev, index: 0); |
172 | if (IS_ERR(ptr: meson_wdt->wdt_base)) |
173 | return PTR_ERR(ptr: meson_wdt->wdt_base); |
174 | |
175 | meson_wdt->data = device_get_match_data(dev); |
176 | |
177 | meson_wdt->wdt_dev.parent = dev; |
178 | meson_wdt->wdt_dev.info = &meson_wdt_info; |
179 | meson_wdt->wdt_dev.ops = &meson_wdt_ops; |
180 | meson_wdt->wdt_dev.max_timeout = |
181 | meson_wdt->data->terminal_count_mask / meson_wdt->data->count_unit; |
182 | meson_wdt->wdt_dev.min_timeout = MESON_WDT_MIN_TIMEOUT; |
183 | meson_wdt->wdt_dev.timeout = min_t(unsigned int, |
184 | MESON_WDT_TIMEOUT, |
185 | meson_wdt->wdt_dev.max_timeout); |
186 | |
187 | watchdog_set_drvdata(wdd: &meson_wdt->wdt_dev, data: meson_wdt); |
188 | |
189 | watchdog_init_timeout(wdd: &meson_wdt->wdt_dev, timeout_parm: timeout, dev); |
190 | watchdog_set_nowayout(wdd: &meson_wdt->wdt_dev, nowayout); |
191 | watchdog_set_restart_priority(wdd: &meson_wdt->wdt_dev, priority: 128); |
192 | |
193 | meson_wdt_stop(wdt_dev: &meson_wdt->wdt_dev); |
194 | |
195 | watchdog_stop_on_reboot(wdd: &meson_wdt->wdt_dev); |
196 | err = devm_watchdog_register_device(dev, &meson_wdt->wdt_dev); |
197 | if (err) |
198 | return err; |
199 | |
200 | dev_info(dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)" , |
201 | meson_wdt->wdt_dev.timeout, nowayout); |
202 | |
203 | return 0; |
204 | } |
205 | |
206 | static struct platform_driver meson_wdt_driver = { |
207 | .probe = meson_wdt_probe, |
208 | .driver = { |
209 | .name = DRV_NAME, |
210 | .of_match_table = meson_wdt_dt_ids, |
211 | }, |
212 | }; |
213 | |
214 | module_platform_driver(meson_wdt_driver); |
215 | |
216 | module_param(timeout, uint, 0); |
217 | MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds" ); |
218 | |
219 | module_param(nowayout, bool, 0); |
220 | MODULE_PARM_DESC(nowayout, |
221 | "Watchdog cannot be stopped once started (default=" |
222 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")" ); |
223 | |
224 | MODULE_LICENSE("GPL" ); |
225 | MODULE_AUTHOR("Carlo Caione <carlo@caione.org>" ); |
226 | MODULE_DESCRIPTION("Meson Watchdog Timer Driver" ); |
227 | |