1 /*
2 * Watchdog driver for CSR SiRFprimaII and SiRFatlasVI
3 *
4 * Copyright (c) 2013 Cambridge Silicon Radio Limited, a CSR plc group company.
5 *
6 * Licensed under GPLv2 or later.
7 */
8
9 #include <linux/module.h>
10 #include <linux/watchdog.h>
11 #include <linux/platform_device.h>
12 #include <linux/moduleparam.h>
13 #include <linux/of.h>
14 #include <linux/io.h>
15 #include <linux/uaccess.h>
16
17 #define CLOCK_FREQ 1000000
18
19 #define SIRFSOC_TIMER_COUNTER_LO 0x0000
20 #define SIRFSOC_TIMER_MATCH_0 0x0008
21 #define SIRFSOC_TIMER_INT_EN 0x0024
22 #define SIRFSOC_TIMER_WATCHDOG_EN 0x0028
23 #define SIRFSOC_TIMER_LATCH 0x0030
24 #define SIRFSOC_TIMER_LATCHED_LO 0x0034
25
26 #define SIRFSOC_TIMER_WDT_INDEX 5
27
28 #define SIRFSOC_WDT_MIN_TIMEOUT 30 /* 30 secs */
29 #define SIRFSOC_WDT_MAX_TIMEOUT (10 * 60) /* 10 mins */
30 #define SIRFSOC_WDT_DEFAULT_TIMEOUT 30 /* 30 secs */
31
32 static unsigned int timeout = SIRFSOC_WDT_DEFAULT_TIMEOUT;
33 static bool nowayout = WATCHDOG_NOWAYOUT;
34
35 module_param(timeout, uint, 0);
36 module_param(nowayout, bool, 0);
37
38 MODULE_PARM_DESC(timeout, "Default watchdog timeout (in seconds)");
39 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
40 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
41
sirfsoc_wdt_gettimeleft(struct watchdog_device * wdd)42 static unsigned int sirfsoc_wdt_gettimeleft(struct watchdog_device *wdd)
43 {
44 u32 counter, match;
45 void __iomem *wdt_base;
46 int time_left;
47
48 wdt_base = watchdog_get_drvdata(wdd);
49 counter = readl(wdt_base + SIRFSOC_TIMER_COUNTER_LO);
50 match = readl(wdt_base +
51 SIRFSOC_TIMER_MATCH_0 + (SIRFSOC_TIMER_WDT_INDEX << 2));
52
53 time_left = match - counter;
54
55 return time_left / CLOCK_FREQ;
56 }
57
sirfsoc_wdt_updatetimeout(struct watchdog_device * wdd)58 static int sirfsoc_wdt_updatetimeout(struct watchdog_device *wdd)
59 {
60 u32 counter, timeout_ticks;
61 void __iomem *wdt_base;
62
63 timeout_ticks = wdd->timeout * CLOCK_FREQ;
64 wdt_base = watchdog_get_drvdata(wdd);
65
66 /* Enable the latch before reading the LATCH_LO register */
67 writel(1, wdt_base + SIRFSOC_TIMER_LATCH);
68
69 /* Set the TO value */
70 counter = readl(wdt_base + SIRFSOC_TIMER_LATCHED_LO);
71
72 counter += timeout_ticks;
73
74 writel(counter, wdt_base +
75 SIRFSOC_TIMER_MATCH_0 + (SIRFSOC_TIMER_WDT_INDEX << 2));
76
77 return 0;
78 }
79
sirfsoc_wdt_enable(struct watchdog_device * wdd)80 static int sirfsoc_wdt_enable(struct watchdog_device *wdd)
81 {
82 void __iomem *wdt_base = watchdog_get_drvdata(wdd);
83 sirfsoc_wdt_updatetimeout(wdd);
84
85 /*
86 * NOTE: If interrupt is not enabled
87 * then WD-Reset doesn't get generated at all.
88 */
89 writel(readl(wdt_base + SIRFSOC_TIMER_INT_EN)
90 | (1 << SIRFSOC_TIMER_WDT_INDEX),
91 wdt_base + SIRFSOC_TIMER_INT_EN);
92 writel(1, wdt_base + SIRFSOC_TIMER_WATCHDOG_EN);
93
94 return 0;
95 }
96
sirfsoc_wdt_disable(struct watchdog_device * wdd)97 static int sirfsoc_wdt_disable(struct watchdog_device *wdd)
98 {
99 void __iomem *wdt_base = watchdog_get_drvdata(wdd);
100
101 writel(0, wdt_base + SIRFSOC_TIMER_WATCHDOG_EN);
102 writel(readl(wdt_base + SIRFSOC_TIMER_INT_EN)
103 & (~(1 << SIRFSOC_TIMER_WDT_INDEX)),
104 wdt_base + SIRFSOC_TIMER_INT_EN);
105
106 return 0;
107 }
108
sirfsoc_wdt_settimeout(struct watchdog_device * wdd,unsigned int to)109 static int sirfsoc_wdt_settimeout(struct watchdog_device *wdd, unsigned int to)
110 {
111 wdd->timeout = to;
112 sirfsoc_wdt_updatetimeout(wdd);
113
114 return 0;
115 }
116
117 #define OPTIONS (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE)
118
119 static const struct watchdog_info sirfsoc_wdt_ident = {
120 .options = OPTIONS,
121 .firmware_version = 0,
122 .identity = "SiRFSOC Watchdog",
123 };
124
125 static struct watchdog_ops sirfsoc_wdt_ops = {
126 .owner = THIS_MODULE,
127 .start = sirfsoc_wdt_enable,
128 .stop = sirfsoc_wdt_disable,
129 .get_timeleft = sirfsoc_wdt_gettimeleft,
130 .ping = sirfsoc_wdt_updatetimeout,
131 .set_timeout = sirfsoc_wdt_settimeout,
132 };
133
134 static struct watchdog_device sirfsoc_wdd = {
135 .info = &sirfsoc_wdt_ident,
136 .ops = &sirfsoc_wdt_ops,
137 .timeout = SIRFSOC_WDT_DEFAULT_TIMEOUT,
138 .min_timeout = SIRFSOC_WDT_MIN_TIMEOUT,
139 .max_timeout = SIRFSOC_WDT_MAX_TIMEOUT,
140 };
141
sirfsoc_wdt_probe(struct platform_device * pdev)142 static int sirfsoc_wdt_probe(struct platform_device *pdev)
143 {
144 struct resource *res;
145 int ret;
146 void __iomem *base;
147
148 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
149 base = devm_ioremap_resource(&pdev->dev, res);
150 if (IS_ERR(base))
151 return PTR_ERR(base);
152
153 watchdog_set_drvdata(&sirfsoc_wdd, base);
154
155 watchdog_init_timeout(&sirfsoc_wdd, timeout, &pdev->dev);
156 watchdog_set_nowayout(&sirfsoc_wdd, nowayout);
157 sirfsoc_wdd.parent = &pdev->dev;
158
159 ret = watchdog_register_device(&sirfsoc_wdd);
160 if (ret)
161 return ret;
162
163 platform_set_drvdata(pdev, &sirfsoc_wdd);
164
165 return 0;
166 }
167
sirfsoc_wdt_shutdown(struct platform_device * pdev)168 static void sirfsoc_wdt_shutdown(struct platform_device *pdev)
169 {
170 struct watchdog_device *wdd = platform_get_drvdata(pdev);
171
172 sirfsoc_wdt_disable(wdd);
173 }
174
sirfsoc_wdt_remove(struct platform_device * pdev)175 static int sirfsoc_wdt_remove(struct platform_device *pdev)
176 {
177 sirfsoc_wdt_shutdown(pdev);
178 return 0;
179 }
180
181 #ifdef CONFIG_PM_SLEEP
sirfsoc_wdt_suspend(struct device * dev)182 static int sirfsoc_wdt_suspend(struct device *dev)
183 {
184 return 0;
185 }
186
sirfsoc_wdt_resume(struct device * dev)187 static int sirfsoc_wdt_resume(struct device *dev)
188 {
189 struct watchdog_device *wdd = dev_get_drvdata(dev);
190
191 /*
192 * NOTE: Since timer controller registers settings are saved
193 * and restored back by the timer-prima2.c, so we need not
194 * update WD settings except refreshing timeout.
195 */
196 sirfsoc_wdt_updatetimeout(wdd);
197
198 return 0;
199 }
200 #endif
201
202 static SIMPLE_DEV_PM_OPS(sirfsoc_wdt_pm_ops,
203 sirfsoc_wdt_suspend, sirfsoc_wdt_resume);
204
205 static const struct of_device_id sirfsoc_wdt_of_match[] = {
206 { .compatible = "sirf,prima2-tick"},
207 {},
208 };
209 MODULE_DEVICE_TABLE(of, sirfsoc_wdt_of_match);
210
211 static struct platform_driver sirfsoc_wdt_driver = {
212 .driver = {
213 .name = "sirfsoc-wdt",
214 .pm = &sirfsoc_wdt_pm_ops,
215 .of_match_table = sirfsoc_wdt_of_match,
216 },
217 .probe = sirfsoc_wdt_probe,
218 .remove = sirfsoc_wdt_remove,
219 .shutdown = sirfsoc_wdt_shutdown,
220 };
221 module_platform_driver(sirfsoc_wdt_driver);
222
223 MODULE_DESCRIPTION("SiRF SoC watchdog driver");
224 MODULE_AUTHOR("Xianglong Du <Xianglong.Du@csr.com>");
225 MODULE_LICENSE("GPL v2");
226 MODULE_ALIAS("platform:sirfsoc-wdt");
227