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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/module.h>
15#include <linux/moduleparam.h>
16#include <linux/of.h>
17#include <linux/of_device.h>
18#include <linux/platform_device.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
34static bool nowayout = WATCHDOG_NOWAYOUT;
35static unsigned int timeout;
36
37struct meson_wdt_data {
38 unsigned int enable;
39 unsigned int terminal_count_mask;
40 unsigned int count_unit;
41};
42
43static struct meson_wdt_data meson6_wdt_data = {
44 .enable = BIT(22),
45 .terminal_count_mask = 0x3fffff,
46 .count_unit = 100000,
47};
48
49static struct meson_wdt_data meson8b_wdt_data = {
50 .enable = BIT(19),
51 .terminal_count_mask = 0xffff,
52 .count_unit = 7812,
53};
54
55struct meson_wdt_dev {
56 struct watchdog_device wdt_dev;
57 void __iomem *wdt_base;
58 const struct meson_wdt_data *data;
59};
60
61static 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(wdt_dev);
65 u32 tc_reboot = MESON_WDT_DC_RESET;
66
67 tc_reboot |= meson_wdt->data->enable;
68
69 while (1) {
70 writel(tc_reboot, meson_wdt->wdt_base + MESON_WDT_TC);
71 mdelay(5);
72 }
73
74 return 0;
75}
76
77static int meson_wdt_ping(struct watchdog_device *wdt_dev)
78{
79 struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
80
81 writel(0, meson_wdt->wdt_base + MESON_WDT_RESET);
82
83 return 0;
84}
85
86static 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(wdt_dev);
90 u32 reg;
91
92 reg = readl(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(reg, meson_wdt->wdt_base + MESON_WDT_TC);
96}
97
98static 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
109static int meson_wdt_stop(struct watchdog_device *wdt_dev)
110{
111 struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
112 u32 reg;
113
114 reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
115 reg &= ~meson_wdt->data->enable;
116 writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
117
118 return 0;
119}
120
121static int meson_wdt_start(struct watchdog_device *wdt_dev)
122{
123 struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
124 u32 reg;
125
126 meson_wdt_change_timeout(wdt_dev, meson_wdt->wdt_dev.timeout);
127 meson_wdt_ping(wdt_dev);
128
129 reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
130 reg |= meson_wdt->data->enable;
131 writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
132
133 return 0;
134}
135
136static const struct watchdog_info meson_wdt_info = {
137 .identity = DRV_NAME,
138 .options = WDIOF_SETTIMEOUT |
139 WDIOF_KEEPALIVEPING |
140 WDIOF_MAGICCLOSE,
141};
142
143static 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
152static 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 { }
158};
159MODULE_DEVICE_TABLE(of, meson_wdt_dt_ids);
160
161static 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, sizeof(*meson_wdt), GFP_KERNEL);
168 if (!meson_wdt)
169 return -ENOMEM;
170
171 meson_wdt->wdt_base = devm_platform_ioremap_resource(pdev, 0);
172 if (IS_ERR(meson_wdt->wdt_base))
173 return PTR_ERR(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(&meson_wdt->wdt_dev, meson_wdt);
188
189 watchdog_init_timeout(&meson_wdt->wdt_dev, timeout, dev);
190 watchdog_set_nowayout(&meson_wdt->wdt_dev, nowayout);
191 watchdog_set_restart_priority(&meson_wdt->wdt_dev, 128);
192
193 meson_wdt_stop(&meson_wdt->wdt_dev);
194
195 watchdog_stop_on_reboot(&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
206static 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
214module_platform_driver(meson_wdt_driver);
215
216module_param(timeout, uint, 0);
217MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
218
219module_param(nowayout, bool, 0);
220MODULE_PARM_DESC(nowayout,
221 "Watchdog cannot be stopped once started (default="
222 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
223
224MODULE_LICENSE("GPL");
225MODULE_AUTHOR("Carlo Caione <carlo@caione.org>");
226MODULE_DESCRIPTION("Meson Watchdog Timer Driver");
227
