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