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Linux/drivers/watchdog/sirfsoc_wdt.c

  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 
 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 
 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 
 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 
 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 
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 
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 
158         ret = watchdog_register_device(&sirfsoc_wdd);
159         if (ret)
160                 return ret;
161 
162         platform_set_drvdata(pdev, &sirfsoc_wdd);
163 
164         return 0;
165 }
166 
167 static void sirfsoc_wdt_shutdown(struct platform_device *pdev)
168 {
169         struct watchdog_device *wdd = platform_get_drvdata(pdev);
170 
171         sirfsoc_wdt_disable(wdd);
172 }
173 
174 static int sirfsoc_wdt_remove(struct platform_device *pdev)
175 {
176         sirfsoc_wdt_shutdown(pdev);
177         return 0;
178 }
179 
180 #ifdef  CONFIG_PM_SLEEP
181 static int sirfsoc_wdt_suspend(struct device *dev)
182 {
183         return 0;
184 }
185 
186 static int sirfsoc_wdt_resume(struct device *dev)
187 {
188         struct watchdog_device *wdd = dev_get_drvdata(dev);
189 
190         /*
191          * NOTE: Since timer controller registers settings are saved
192          * and restored back by the timer-prima2.c, so we need not
193          * update WD settings except refreshing timeout.
194          */
195         sirfsoc_wdt_updatetimeout(wdd);
196 
197         return 0;
198 }
199 #endif
200 
201 static SIMPLE_DEV_PM_OPS(sirfsoc_wdt_pm_ops,
202                 sirfsoc_wdt_suspend, sirfsoc_wdt_resume);
203 
204 static const struct of_device_id sirfsoc_wdt_of_match[] = {
205         { .compatible = "sirf,prima2-tick"},
206         {},
207 };
208 MODULE_DEVICE_TABLE(of, sirfsoc_wdt_of_match);
209 
210 static struct platform_driver sirfsoc_wdt_driver = {
211         .driver = {
212                 .name = "sirfsoc-wdt",
213                 .owner = THIS_MODULE,
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 

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