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16#include <linux/delay.h>
17#include <linux/reboot.h>
18#include <linux/types.h>
19#include <linux/module.h>
20#include <linux/io.h>
21#include <linux/watchdog.h>
22#include <linux/platform_device.h>
23#include <linux/of_address.h>
24#include <linux/of_platform.h>
25
26#define PM_RSTC 0x1c
27#define PM_RSTS 0x20
28#define PM_WDOG 0x24
29
30#define PM_PASSWORD 0x5a000000
31
32#define PM_WDOG_TIME_SET 0x000fffff
33#define PM_RSTC_WRCFG_CLR 0xffffffcf
34#define PM_RSTS_HADWRH_SET 0x00000040
35#define PM_RSTC_WRCFG_SET 0x00000030
36#define PM_RSTC_WRCFG_FULL_RESET 0x00000020
37#define PM_RSTC_RESET 0x00000102
38
39
40
41
42
43
44#define PM_RSTS_RASPBERRYPI_HALT 0x555
45
46#define SECS_TO_WDOG_TICKS(x) ((x) << 16)
47#define WDOG_TICKS_TO_SECS(x) ((x) >> 16)
48
49struct bcm2835_wdt {
50 void __iomem *base;
51 spinlock_t lock;
52 struct notifier_block restart_handler;
53};
54
55static unsigned int heartbeat;
56static bool nowayout = WATCHDOG_NOWAYOUT;
57
58static int bcm2835_wdt_start(struct watchdog_device *wdog)
59{
60 struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
61 uint32_t cur;
62 unsigned long flags;
63
64 spin_lock_irqsave(&wdt->lock, flags);
65
66 writel_relaxed(PM_PASSWORD | (SECS_TO_WDOG_TICKS(wdog->timeout) &
67 PM_WDOG_TIME_SET), wdt->base + PM_WDOG);
68 cur = readl_relaxed(wdt->base + PM_RSTC);
69 writel_relaxed(PM_PASSWORD | (cur & PM_RSTC_WRCFG_CLR) |
70 PM_RSTC_WRCFG_FULL_RESET, wdt->base + PM_RSTC);
71
72 spin_unlock_irqrestore(&wdt->lock, flags);
73
74 return 0;
75}
76
77static int bcm2835_wdt_stop(struct watchdog_device *wdog)
78{
79 struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
80
81 writel_relaxed(PM_PASSWORD | PM_RSTC_RESET, wdt->base + PM_RSTC);
82 return 0;
83}
84
85static int bcm2835_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t)
86{
87 wdog->timeout = t;
88 return 0;
89}
90
91static unsigned int bcm2835_wdt_get_timeleft(struct watchdog_device *wdog)
92{
93 struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
94
95 uint32_t ret = readl_relaxed(wdt->base + PM_WDOG);
96 return WDOG_TICKS_TO_SECS(ret & PM_WDOG_TIME_SET);
97}
98
99static struct watchdog_ops bcm2835_wdt_ops = {
100 .owner = THIS_MODULE,
101 .start = bcm2835_wdt_start,
102 .stop = bcm2835_wdt_stop,
103 .set_timeout = bcm2835_wdt_set_timeout,
104 .get_timeleft = bcm2835_wdt_get_timeleft,
105};
106
107static struct watchdog_info bcm2835_wdt_info = {
108 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
109 WDIOF_KEEPALIVEPING,
110 .identity = "Broadcom BCM2835 Watchdog timer",
111};
112
113static struct watchdog_device bcm2835_wdt_wdd = {
114 .info = &bcm2835_wdt_info,
115 .ops = &bcm2835_wdt_ops,
116 .min_timeout = 1,
117 .max_timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
118 .timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
119};
120
121static int
122bcm2835_restart(struct notifier_block *this, unsigned long mode, void *cmd)
123{
124 struct bcm2835_wdt *wdt = container_of(this, struct bcm2835_wdt,
125 restart_handler);
126 u32 val;
127
128
129 writel_relaxed(10 | PM_PASSWORD, wdt->base + PM_WDOG);
130 val = readl_relaxed(wdt->base + PM_RSTC);
131 val &= PM_RSTC_WRCFG_CLR;
132 val |= PM_PASSWORD | PM_RSTC_WRCFG_FULL_RESET;
133 writel_relaxed(val, wdt->base + PM_RSTC);
134
135
136 mdelay(1);
137
138 return 0;
139}
140
141
142
143
144
145
146static void bcm2835_power_off(void)
147{
148 struct device_node *np =
149 of_find_compatible_node(NULL, NULL, "brcm,bcm2835-pm-wdt");
150 struct platform_device *pdev = of_find_device_by_node(np);
151 struct bcm2835_wdt *wdt = platform_get_drvdata(pdev);
152 u32 val;
153
154
155
156
157
158
159 val = readl_relaxed(wdt->base + PM_RSTS);
160 val |= PM_PASSWORD | PM_RSTS_RASPBERRYPI_HALT;
161 writel_relaxed(val, wdt->base + PM_RSTS);
162
163
164 bcm2835_restart(&wdt->restart_handler, REBOOT_HARD, NULL);
165}
166
167static int bcm2835_wdt_probe(struct platform_device *pdev)
168{
169 struct device *dev = &pdev->dev;
170 struct device_node *np = dev->of_node;
171 struct bcm2835_wdt *wdt;
172 int err;
173
174 wdt = devm_kzalloc(dev, sizeof(struct bcm2835_wdt), GFP_KERNEL);
175 if (!wdt)
176 return -ENOMEM;
177 platform_set_drvdata(pdev, wdt);
178
179 spin_lock_init(&wdt->lock);
180
181 wdt->base = of_iomap(np, 0);
182 if (!wdt->base) {
183 dev_err(dev, "Failed to remap watchdog regs");
184 return -ENODEV;
185 }
186
187 watchdog_set_drvdata(&bcm2835_wdt_wdd, wdt);
188 watchdog_init_timeout(&bcm2835_wdt_wdd, heartbeat, dev);
189 watchdog_set_nowayout(&bcm2835_wdt_wdd, nowayout);
190 bcm2835_wdt_wdd.parent = &pdev->dev;
191 err = watchdog_register_device(&bcm2835_wdt_wdd);
192 if (err) {
193 dev_err(dev, "Failed to register watchdog device");
194 iounmap(wdt->base);
195 return err;
196 }
197
198 wdt->restart_handler.notifier_call = bcm2835_restart;
199 wdt->restart_handler.priority = 128;
200 register_restart_handler(&wdt->restart_handler);
201 if (pm_power_off == NULL)
202 pm_power_off = bcm2835_power_off;
203
204 dev_info(dev, "Broadcom BCM2835 watchdog timer");
205 return 0;
206}
207
208static int bcm2835_wdt_remove(struct platform_device *pdev)
209{
210 struct bcm2835_wdt *wdt = platform_get_drvdata(pdev);
211
212 unregister_restart_handler(&wdt->restart_handler);
213 if (pm_power_off == bcm2835_power_off)
214 pm_power_off = NULL;
215 watchdog_unregister_device(&bcm2835_wdt_wdd);
216 iounmap(wdt->base);
217
218 return 0;
219}
220
221static void bcm2835_wdt_shutdown(struct platform_device *pdev)
222{
223 bcm2835_wdt_stop(&bcm2835_wdt_wdd);
224}
225
226static const struct of_device_id bcm2835_wdt_of_match[] = {
227 { .compatible = "brcm,bcm2835-pm-wdt", },
228 {},
229};
230MODULE_DEVICE_TABLE(of, bcm2835_wdt_of_match);
231
232static struct platform_driver bcm2835_wdt_driver = {
233 .probe = bcm2835_wdt_probe,
234 .remove = bcm2835_wdt_remove,
235 .shutdown = bcm2835_wdt_shutdown,
236 .driver = {
237 .name = "bcm2835-wdt",
238 .of_match_table = bcm2835_wdt_of_match,
239 },
240};
241module_platform_driver(bcm2835_wdt_driver);
242
243module_param(heartbeat, uint, 0);
244MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds");
245
246module_param(nowayout, bool, 0);
247MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
248 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
249
250MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
251MODULE_DESCRIPTION("Driver for Broadcom BCM2835 watchdog timer");
252MODULE_LICENSE("GPL");
253
