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                 .pm = &sirfsoc_wdt_pm_ops,
 214                 .of_match_table = sirfsoc_wdt_of_match,
 215         },
 216         .probe = sirfsoc_wdt_probe,
 217         .remove = sirfsoc_wdt_remove,
 218         .shutdown = sirfsoc_wdt_shutdown,
 219 };
 220 module_platform_driver(sirfsoc_wdt_driver);
 221
 222 MODULE_DESCRIPTION("SiRF SoC watchdog driver");
 223 MODULE_AUTHOR("Xianglong Du <Xianglong.Du@csr.com>");
 224 MODULE_LICENSE("GPL v2");
 225 MODULE_ALIAS("platform:sirfsoc-wdt");