thermal: rockchip: fixes the conversion table
[sfrench/cifs-2.6.git] / drivers / watchdog / bcm2835_wdt.c
1 /*
2  * Watchdog driver for Broadcom BCM2835
3  *
4  * "bcm2708_wdog" driver written by Luke Diamand that was obtained from
5  * branch "rpi-3.6.y" of git://github.com/raspberrypi/linux.git was used
6  * as a hardware reference for the Broadcom BCM2835 watchdog timer.
7  *
8  * Copyright (C) 2013 Lubomir Rintel <lkundrak@v3.sk>
9  *
10  * This program is free software; you can redistribute it and/or modify it
11  * under the terms of the GNU General Public License as published by the
12  * Free Software Foundation; either version 2 of the License, or (at your
13  * option) any later version.
14  */
15
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  * The Raspberry Pi firmware uses the RSTS register to know which partiton
41  * to boot from. The partiton value is spread into bits 0, 2, 4, 6, 8, 10.
42  * Partiton 63 is a special partition used by the firmware to indicate halt.
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
49 struct bcm2835_wdt {
50         void __iomem            *base;
51         spinlock_t              lock;
52         struct notifier_block   restart_handler;
53 };
54
55 static unsigned int heartbeat;
56 static bool nowayout = WATCHDOG_NOWAYOUT;
57
58 static 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
77 static 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
85 static unsigned int bcm2835_wdt_get_timeleft(struct watchdog_device *wdog)
86 {
87         struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
88
89         uint32_t ret = readl_relaxed(wdt->base + PM_WDOG);
90         return WDOG_TICKS_TO_SECS(ret & PM_WDOG_TIME_SET);
91 }
92
93 static const struct watchdog_ops bcm2835_wdt_ops = {
94         .owner =        THIS_MODULE,
95         .start =        bcm2835_wdt_start,
96         .stop =         bcm2835_wdt_stop,
97         .get_timeleft = bcm2835_wdt_get_timeleft,
98 };
99
100 static const struct watchdog_info bcm2835_wdt_info = {
101         .options =      WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
102                         WDIOF_KEEPALIVEPING,
103         .identity =     "Broadcom BCM2835 Watchdog timer",
104 };
105
106 static struct watchdog_device bcm2835_wdt_wdd = {
107         .info =         &bcm2835_wdt_info,
108         .ops =          &bcm2835_wdt_ops,
109         .min_timeout =  1,
110         .max_timeout =  WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
111         .timeout =      WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
112 };
113
114 static int
115 bcm2835_restart(struct notifier_block *this, unsigned long mode, void *cmd)
116 {
117         struct bcm2835_wdt *wdt = container_of(this, struct bcm2835_wdt,
118                                                restart_handler);
119         u32 val;
120
121         /* use a timeout of 10 ticks (~150us) */
122         writel_relaxed(10 | PM_PASSWORD, wdt->base + PM_WDOG);
123         val = readl_relaxed(wdt->base + PM_RSTC);
124         val &= PM_RSTC_WRCFG_CLR;
125         val |= PM_PASSWORD | PM_RSTC_WRCFG_FULL_RESET;
126         writel_relaxed(val, wdt->base + PM_RSTC);
127
128         /* No sleeping, possibly atomic. */
129         mdelay(1);
130
131         return 0;
132 }
133
134 /*
135  * We can't really power off, but if we do the normal reset scheme, and
136  * indicate to bootcode.bin not to reboot, then most of the chip will be
137  * powered off.
138  */
139 static void bcm2835_power_off(void)
140 {
141         struct device_node *np =
142                 of_find_compatible_node(NULL, NULL, "brcm,bcm2835-pm-wdt");
143         struct platform_device *pdev = of_find_device_by_node(np);
144         struct bcm2835_wdt *wdt = platform_get_drvdata(pdev);
145         u32 val;
146
147         /*
148          * We set the watchdog hard reset bit here to distinguish this reset
149          * from the normal (full) reset. bootcode.bin will not reboot after a
150          * hard reset.
151          */
152         val = readl_relaxed(wdt->base + PM_RSTS);
153         val |= PM_PASSWORD | PM_RSTS_RASPBERRYPI_HALT;
154         writel_relaxed(val, wdt->base + PM_RSTS);
155
156         /* Continue with normal reset mechanism */
157         bcm2835_restart(&wdt->restart_handler, REBOOT_HARD, NULL);
158 }
159
160 static int bcm2835_wdt_probe(struct platform_device *pdev)
161 {
162         struct device *dev = &pdev->dev;
163         struct device_node *np = dev->of_node;
164         struct bcm2835_wdt *wdt;
165         int err;
166
167         wdt = devm_kzalloc(dev, sizeof(struct bcm2835_wdt), GFP_KERNEL);
168         if (!wdt)
169                 return -ENOMEM;
170         platform_set_drvdata(pdev, wdt);
171
172         spin_lock_init(&wdt->lock);
173
174         wdt->base = of_iomap(np, 0);
175         if (!wdt->base) {
176                 dev_err(dev, "Failed to remap watchdog regs");
177                 return -ENODEV;
178         }
179
180         watchdog_set_drvdata(&bcm2835_wdt_wdd, wdt);
181         watchdog_init_timeout(&bcm2835_wdt_wdd, heartbeat, dev);
182         watchdog_set_nowayout(&bcm2835_wdt_wdd, nowayout);
183         bcm2835_wdt_wdd.parent = &pdev->dev;
184         err = watchdog_register_device(&bcm2835_wdt_wdd);
185         if (err) {
186                 dev_err(dev, "Failed to register watchdog device");
187                 iounmap(wdt->base);
188                 return err;
189         }
190
191         wdt->restart_handler.notifier_call = bcm2835_restart;
192         wdt->restart_handler.priority = 128;
193         register_restart_handler(&wdt->restart_handler);
194         if (pm_power_off == NULL)
195                 pm_power_off = bcm2835_power_off;
196
197         dev_info(dev, "Broadcom BCM2835 watchdog timer");
198         return 0;
199 }
200
201 static int bcm2835_wdt_remove(struct platform_device *pdev)
202 {
203         struct bcm2835_wdt *wdt = platform_get_drvdata(pdev);
204
205         unregister_restart_handler(&wdt->restart_handler);
206         if (pm_power_off == bcm2835_power_off)
207                 pm_power_off = NULL;
208         watchdog_unregister_device(&bcm2835_wdt_wdd);
209         iounmap(wdt->base);
210
211         return 0;
212 }
213
214 static void bcm2835_wdt_shutdown(struct platform_device *pdev)
215 {
216         bcm2835_wdt_stop(&bcm2835_wdt_wdd);
217 }
218
219 static const struct of_device_id bcm2835_wdt_of_match[] = {
220         { .compatible = "brcm,bcm2835-pm-wdt", },
221         {},
222 };
223 MODULE_DEVICE_TABLE(of, bcm2835_wdt_of_match);
224
225 static struct platform_driver bcm2835_wdt_driver = {
226         .probe          = bcm2835_wdt_probe,
227         .remove         = bcm2835_wdt_remove,
228         .shutdown       = bcm2835_wdt_shutdown,
229         .driver = {
230                 .name =         "bcm2835-wdt",
231                 .of_match_table = bcm2835_wdt_of_match,
232         },
233 };
234 module_platform_driver(bcm2835_wdt_driver);
235
236 module_param(heartbeat, uint, 0);
237 MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds");
238
239 module_param(nowayout, bool, 0);
240 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
241                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
242
243 MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
244 MODULE_DESCRIPTION("Driver for Broadcom BCM2835 watchdog timer");
245 MODULE_LICENSE("GPL");