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13#include <linux/delay.h>
14#include <linux/types.h>
15#include <linux/mfd/bcm2835-pm.h>
16#include <linux/module.h>
17#include <linux/io.h>
18#include <linux/watchdog.h>
19#include <linux/platform_device.h>
20#include <linux/of_address.h>
21#include <linux/of_platform.h>
22
23#define PM_RSTC 0x1c
24#define PM_RSTS 0x20
25#define PM_WDOG 0x24
26
27#define PM_PASSWORD 0x5a000000
28
29#define PM_WDOG_TIME_SET 0x000fffff
30#define PM_RSTC_WRCFG_CLR 0xffffffcf
31#define PM_RSTS_HADWRH_SET 0x00000040
32#define PM_RSTC_WRCFG_SET 0x00000030
33#define PM_RSTC_WRCFG_FULL_RESET 0x00000020
34#define PM_RSTC_RESET 0x00000102
35
36
37
38
39
40
41#define PM_RSTS_RASPBERRYPI_HALT 0x555
42
43#define SECS_TO_WDOG_TICKS(x) ((x) << 16)
44#define WDOG_TICKS_TO_SECS(x) ((x) >> 16)
45
46struct bcm2835_wdt {
47 void __iomem *base;
48 spinlock_t lock;
49};
50
51static struct bcm2835_wdt *bcm2835_power_off_wdt;
52
53static unsigned int heartbeat;
54static bool nowayout = WATCHDOG_NOWAYOUT;
55
56static bool bcm2835_wdt_is_running(struct bcm2835_wdt *wdt)
57{
58 uint32_t cur;
59
60 cur = readl(wdt->base + PM_RSTC);
61
62 return !!(cur & PM_RSTC_WRCFG_FULL_RESET);
63}
64
65static int bcm2835_wdt_start(struct watchdog_device *wdog)
66{
67 struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
68 uint32_t cur;
69 unsigned long flags;
70
71 spin_lock_irqsave(&wdt->lock, flags);
72
73 writel_relaxed(PM_PASSWORD | (SECS_TO_WDOG_TICKS(wdog->timeout) &
74 PM_WDOG_TIME_SET), wdt->base + PM_WDOG);
75 cur = readl_relaxed(wdt->base + PM_RSTC);
76 writel_relaxed(PM_PASSWORD | (cur & PM_RSTC_WRCFG_CLR) |
77 PM_RSTC_WRCFG_FULL_RESET, wdt->base + PM_RSTC);
78
79 spin_unlock_irqrestore(&wdt->lock, flags);
80
81 return 0;
82}
83
84static int bcm2835_wdt_stop(struct watchdog_device *wdog)
85{
86 struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
87
88 writel_relaxed(PM_PASSWORD | PM_RSTC_RESET, wdt->base + PM_RSTC);
89 return 0;
90}
91
92static unsigned int bcm2835_wdt_get_timeleft(struct watchdog_device *wdog)
93{
94 struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
95
96 uint32_t ret = readl_relaxed(wdt->base + PM_WDOG);
97 return WDOG_TICKS_TO_SECS(ret & PM_WDOG_TIME_SET);
98}
99
100static void __bcm2835_restart(struct bcm2835_wdt *wdt)
101{
102 u32 val;
103
104
105 writel_relaxed(10 | PM_PASSWORD, wdt->base + PM_WDOG);
106 val = readl_relaxed(wdt->base + PM_RSTC);
107 val &= PM_RSTC_WRCFG_CLR;
108 val |= PM_PASSWORD | PM_RSTC_WRCFG_FULL_RESET;
109 writel_relaxed(val, wdt->base + PM_RSTC);
110
111
112 mdelay(1);
113}
114
115static int bcm2835_restart(struct watchdog_device *wdog,
116 unsigned long action, void *data)
117{
118 struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
119
120 __bcm2835_restart(wdt);
121
122 return 0;
123}
124
125static const struct watchdog_ops bcm2835_wdt_ops = {
126 .owner = THIS_MODULE,
127 .start = bcm2835_wdt_start,
128 .stop = bcm2835_wdt_stop,
129 .get_timeleft = bcm2835_wdt_get_timeleft,
130 .restart = bcm2835_restart,
131};
132
133static const struct watchdog_info bcm2835_wdt_info = {
134 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
135 WDIOF_KEEPALIVEPING,
136 .identity = "Broadcom BCM2835 Watchdog timer",
137};
138
139static struct watchdog_device bcm2835_wdt_wdd = {
140 .info = &bcm2835_wdt_info,
141 .ops = &bcm2835_wdt_ops,
142 .min_timeout = 1,
143 .max_timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
144 .timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
145};
146
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150
151
152static void bcm2835_power_off(void)
153{
154 struct bcm2835_wdt *wdt = bcm2835_power_off_wdt;
155 u32 val;
156
157
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160
161
162 val = readl_relaxed(wdt->base + PM_RSTS);
163 val |= PM_PASSWORD | PM_RSTS_RASPBERRYPI_HALT;
164 writel_relaxed(val, wdt->base + PM_RSTS);
165
166
167 __bcm2835_restart(wdt);
168}
169
170static int bcm2835_wdt_probe(struct platform_device *pdev)
171{
172 struct bcm2835_pm *pm = dev_get_drvdata(pdev->dev.parent);
173 struct device *dev = &pdev->dev;
174 struct bcm2835_wdt *wdt;
175 int err;
176
177 wdt = devm_kzalloc(dev, sizeof(struct bcm2835_wdt), GFP_KERNEL);
178 if (!wdt)
179 return -ENOMEM;
180
181 spin_lock_init(&wdt->lock);
182
183 wdt->base = pm->base;
184
185 watchdog_set_drvdata(&bcm2835_wdt_wdd, wdt);
186 watchdog_init_timeout(&bcm2835_wdt_wdd, heartbeat, dev);
187 watchdog_set_nowayout(&bcm2835_wdt_wdd, nowayout);
188 bcm2835_wdt_wdd.parent = dev;
189 if (bcm2835_wdt_is_running(wdt)) {
190
191
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194
195
196
197
198 set_bit(WDOG_HW_RUNNING, &bcm2835_wdt_wdd.status);
199 }
200
201 watchdog_set_restart_priority(&bcm2835_wdt_wdd, 128);
202
203 watchdog_stop_on_reboot(&bcm2835_wdt_wdd);
204 err = devm_watchdog_register_device(dev, &bcm2835_wdt_wdd);
205 if (err)
206 return err;
207
208 if (of_device_is_system_power_controller(pdev->dev.parent->of_node)) {
209 if (!pm_power_off) {
210 pm_power_off = bcm2835_power_off;
211 bcm2835_power_off_wdt = wdt;
212 } else {
213 dev_info(dev, "Poweroff handler already present!\n");
214 }
215 }
216
217 dev_info(dev, "Broadcom BCM2835 watchdog timer");
218 return 0;
219}
220
221static int bcm2835_wdt_remove(struct platform_device *pdev)
222{
223 if (pm_power_off == bcm2835_power_off)
224 pm_power_off = NULL;
225
226 return 0;
227}
228
229static struct platform_driver bcm2835_wdt_driver = {
230 .probe = bcm2835_wdt_probe,
231 .remove = bcm2835_wdt_remove,
232 .driver = {
233 .name = "bcm2835-wdt",
234 },
235};
236module_platform_driver(bcm2835_wdt_driver);
237
238module_param(heartbeat, uint, 0);
239MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds");
240
241module_param(nowayout, bool, 0);
242MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
243 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
244
245MODULE_ALIAS("platform:bcm2835-wdt");
246MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
247MODULE_DESCRIPTION("Driver for Broadcom BCM2835 watchdog timer");
248MODULE_LICENSE("GPL");
249
