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13#include <linux/delay.h>
14#include <linux/types.h>
15#include <linux/module.h>
16#include <linux/io.h>
17#include <linux/watchdog.h>
18#include <linux/platform_device.h>
19#include <linux/of_address.h>
20#include <linux/of_platform.h>
21
22#define PM_RSTC 0x1c
23#define PM_RSTS 0x20
24#define PM_WDOG 0x24
25
26#define PM_PASSWORD 0x5a000000
27
28#define PM_WDOG_TIME_SET 0x000fffff
29#define PM_RSTC_WRCFG_CLR 0xffffffcf
30#define PM_RSTS_HADWRH_SET 0x00000040
31#define PM_RSTC_WRCFG_SET 0x00000030
32#define PM_RSTC_WRCFG_FULL_RESET 0x00000020
33#define PM_RSTC_RESET 0x00000102
34
35
36
37
38
39
40#define PM_RSTS_RASPBERRYPI_HALT 0x555
41
42#define SECS_TO_WDOG_TICKS(x) ((x) << 16)
43#define WDOG_TICKS_TO_SECS(x) ((x) >> 16)
44
45struct bcm2835_wdt {
46 void __iomem *base;
47 spinlock_t lock;
48};
49
50static unsigned int heartbeat;
51static bool nowayout = WATCHDOG_NOWAYOUT;
52
53static bool bcm2835_wdt_is_running(struct bcm2835_wdt *wdt)
54{
55 uint32_t cur;
56
57 cur = readl(wdt->base + PM_RSTC);
58
59 return !!(cur & PM_RSTC_WRCFG_FULL_RESET);
60}
61
62static int bcm2835_wdt_start(struct watchdog_device *wdog)
63{
64 struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
65 uint32_t cur;
66 unsigned long flags;
67
68 spin_lock_irqsave(&wdt->lock, flags);
69
70 writel_relaxed(PM_PASSWORD | (SECS_TO_WDOG_TICKS(wdog->timeout) &
71 PM_WDOG_TIME_SET), wdt->base + PM_WDOG);
72 cur = readl_relaxed(wdt->base + PM_RSTC);
73 writel_relaxed(PM_PASSWORD | (cur & PM_RSTC_WRCFG_CLR) |
74 PM_RSTC_WRCFG_FULL_RESET, wdt->base + PM_RSTC);
75
76 spin_unlock_irqrestore(&wdt->lock, flags);
77
78 return 0;
79}
80
81static int bcm2835_wdt_stop(struct watchdog_device *wdog)
82{
83 struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
84
85 writel_relaxed(PM_PASSWORD | PM_RSTC_RESET, wdt->base + PM_RSTC);
86 return 0;
87}
88
89static unsigned int bcm2835_wdt_get_timeleft(struct watchdog_device *wdog)
90{
91 struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
92
93 uint32_t ret = readl_relaxed(wdt->base + PM_WDOG);
94 return WDOG_TICKS_TO_SECS(ret & PM_WDOG_TIME_SET);
95}
96
97static void __bcm2835_restart(struct bcm2835_wdt *wdt)
98{
99 u32 val;
100
101
102 writel_relaxed(10 | PM_PASSWORD, wdt->base + PM_WDOG);
103 val = readl_relaxed(wdt->base + PM_RSTC);
104 val &= PM_RSTC_WRCFG_CLR;
105 val |= PM_PASSWORD | PM_RSTC_WRCFG_FULL_RESET;
106 writel_relaxed(val, wdt->base + PM_RSTC);
107
108
109 mdelay(1);
110}
111
112static int bcm2835_restart(struct watchdog_device *wdog,
113 unsigned long action, void *data)
114{
115 struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
116
117 __bcm2835_restart(wdt);
118
119 return 0;
120}
121
122static const struct watchdog_ops bcm2835_wdt_ops = {
123 .owner = THIS_MODULE,
124 .start = bcm2835_wdt_start,
125 .stop = bcm2835_wdt_stop,
126 .get_timeleft = bcm2835_wdt_get_timeleft,
127 .restart = bcm2835_restart,
128};
129
130static const struct watchdog_info bcm2835_wdt_info = {
131 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
132 WDIOF_KEEPALIVEPING,
133 .identity = "Broadcom BCM2835 Watchdog timer",
134};
135
136static struct watchdog_device bcm2835_wdt_wdd = {
137 .info = &bcm2835_wdt_info,
138 .ops = &bcm2835_wdt_ops,
139 .min_timeout = 1,
140 .max_timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
141 .timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
142};
143
144
145
146
147
148
149static void bcm2835_power_off(void)
150{
151 struct device_node *np =
152 of_find_compatible_node(NULL, NULL, "brcm,bcm2835-pm-wdt");
153 struct platform_device *pdev = of_find_device_by_node(np);
154 struct bcm2835_wdt *wdt = platform_get_drvdata(pdev);
155 u32 val;
156
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159
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 resource *res;
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 platform_set_drvdata(pdev, wdt);
181
182 spin_lock_init(&wdt->lock);
183
184 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
185 wdt->base = devm_ioremap_resource(dev, res);
186 if (IS_ERR(wdt->base))
187 return PTR_ERR(wdt->base);
188
189 watchdog_set_drvdata(&bcm2835_wdt_wdd, wdt);
190 watchdog_init_timeout(&bcm2835_wdt_wdd, heartbeat, dev);
191 watchdog_set_nowayout(&bcm2835_wdt_wdd, nowayout);
192 bcm2835_wdt_wdd.parent = dev;
193 if (bcm2835_wdt_is_running(wdt)) {
194
195
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197
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199
200
201
202 set_bit(WDOG_HW_RUNNING, &bcm2835_wdt_wdd.status);
203 }
204
205 watchdog_set_restart_priority(&bcm2835_wdt_wdd, 128);
206
207 watchdog_stop_on_reboot(&bcm2835_wdt_wdd);
208 err = devm_watchdog_register_device(dev, &bcm2835_wdt_wdd);
209 if (err) {
210 dev_err(dev, "Failed to register watchdog device");
211 return err;
212 }
213
214 if (pm_power_off == NULL)
215 pm_power_off = bcm2835_power_off;
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 const struct of_device_id bcm2835_wdt_of_match[] = {
230 { .compatible = "brcm,bcm2835-pm-wdt", },
231 {},
232};
233MODULE_DEVICE_TABLE(of, bcm2835_wdt_of_match);
234
235static struct platform_driver bcm2835_wdt_driver = {
236 .probe = bcm2835_wdt_probe,
237 .remove = bcm2835_wdt_remove,
238 .driver = {
239 .name = "bcm2835-wdt",
240 .of_match_table = bcm2835_wdt_of_match,
241 },
242};
243module_platform_driver(bcm2835_wdt_driver);
244
245module_param(heartbeat, uint, 0);
246MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds");
247
248module_param(nowayout, bool, 0);
249MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
250 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
251
252MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
253MODULE_DESCRIPTION("Driver for Broadcom BCM2835 watchdog timer");
254MODULE_LICENSE("GPL");
255
