drivers/watchdog/sama5d4_wdt.c

   1 /*
   2  * Driver for Atmel SAMA5D4 Watchdog Timer
   3  *
   4  * Copyright (C) 2015 Atmel Corporation
   5  *
   6  * Licensed under GPLv2.
   7  */
   8
   9 #include <linux/interrupt.h>
  10 #include <linux/io.h>
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/of.h>
  14 #include <linux/of_irq.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/reboot.h>
  17 #include <linux/watchdog.h>
  18
  19 #include "at91sam9_wdt.h"
  20
  21 /* minimum and maximum watchdog timeout, in seconds */
  22 #define MIN_WDT_TIMEOUT         1
  23 #define MAX_WDT_TIMEOUT         16
  24 #define WDT_DEFAULT_TIMEOUT     MAX_WDT_TIMEOUT
  25
  26 #define WDT_SEC2TICKS(s)        ((s) ? (((s) << 8) - 1) : 0)
  27
  28 struct sama5d4_wdt {
  29         struct watchdog_device  wdd;
  30         void __iomem            *reg_base;
  31         u32                     mr;
  32 };
  33
  34 static int wdt_timeout = WDT_DEFAULT_TIMEOUT;
  35 static bool nowayout = WATCHDOG_NOWAYOUT;
  36
  37 module_param(wdt_timeout, int, 0);
  38 MODULE_PARM_DESC(wdt_timeout,
  39         "Watchdog timeout in seconds. (default = "
  40         __MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")");
  41
  42 module_param(nowayout, bool, 0);
  43 MODULE_PARM_DESC(nowayout,
  44         "Watchdog cannot be stopped once started (default="
  45         __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  46
  47 #define wdt_read(wdt, field) \
  48         readl_relaxed((wdt)->reg_base + (field))
  49
  50 #define wdt_write(wtd, field, val) \
  51         writel_relaxed((val), (wdt)->reg_base + (field))
  52
  53 static int sama5d4_wdt_start(struct watchdog_device *wdd)
  54 {
  55         struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
  56
  57         wdt->mr &= ~AT91_WDT_WDDIS;
  58         wdt_write(wdt, AT91_WDT_MR, wdt->mr);
  59
  60         return 0;
  61 }
  62
  63 static int sama5d4_wdt_stop(struct watchdog_device *wdd)
  64 {
  65         struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
  66
  67         wdt->mr |= AT91_WDT_WDDIS;
  68         wdt_write(wdt, AT91_WDT_MR, wdt->mr);
  69
  70         return 0;
  71 }
  72
  73 static int sama5d4_wdt_ping(struct watchdog_device *wdd)
  74 {
  75         struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
  76
  77         wdt_write(wdt, AT91_WDT_CR, AT91_WDT_KEY | AT91_WDT_WDRSTT);
  78
  79         return 0;
  80 }
  81
  82 static int sama5d4_wdt_set_timeout(struct watchdog_device *wdd,
  83                                  unsigned int timeout)
  84 {
  85         struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
  86         u32 value = WDT_SEC2TICKS(timeout);
  87
  88         wdt->mr &= ~AT91_WDT_WDV;
  89         wdt->mr &= ~AT91_WDT_WDD;
  90         wdt->mr |= AT91_WDT_SET_WDV(value);
  91         wdt->mr |= AT91_WDT_SET_WDD(value);
  92         wdt_write(wdt, AT91_WDT_MR, wdt->mr);
  93
  94         wdd->timeout = timeout;
  95
  96         return 0;
  97 }
  98
  99 static const struct watchdog_info sama5d4_wdt_info = {
 100         .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
 101         .identity = "Atmel SAMA5D4 Watchdog",
 102 };
 103
 104 static const struct watchdog_ops sama5d4_wdt_ops = {
 105         .owner = THIS_MODULE,
 106         .start = sama5d4_wdt_start,
 107         .stop = sama5d4_wdt_stop,
 108         .ping = sama5d4_wdt_ping,
 109         .set_timeout = sama5d4_wdt_set_timeout,
 110 };
 111
 112 static irqreturn_t sama5d4_wdt_irq_handler(int irq, void *dev_id)
 113 {
 114         struct sama5d4_wdt *wdt = platform_get_drvdata(dev_id);
 115
 116         if (wdt_read(wdt, AT91_WDT_SR)) {
 117                 pr_crit("Atmel Watchdog Software Reset\n");
 118                 emergency_restart();
 119                 pr_crit("Reboot didn't succeed\n");
 120         }
 121
 122         return IRQ_HANDLED;
 123 }
 124
 125 static int of_sama5d4_wdt_init(struct device_node *np, struct sama5d4_wdt *wdt)
 126 {
 127         const char *tmp;
 128
 129         wdt->mr = AT91_WDT_WDDIS;
 130
 131         if (!of_property_read_string(np, "atmel,watchdog-type", &tmp) &&
 132             !strcmp(tmp, "software"))
 133                 wdt->mr |= AT91_WDT_WDFIEN;
 134         else
 135                 wdt->mr |= AT91_WDT_WDRSTEN;
 136
 137         if (of_property_read_bool(np, "atmel,idle-halt"))
 138                 wdt->mr |= AT91_WDT_WDIDLEHLT;
 139
 140         if (of_property_read_bool(np, "atmel,dbg-halt"))
 141                 wdt->mr |= AT91_WDT_WDDBGHLT;
 142
 143         return 0;
 144 }
 145
 146 static int sama5d4_wdt_init(struct sama5d4_wdt *wdt)
 147 {
 148         struct watchdog_device *wdd = &wdt->wdd;
 149         u32 value = WDT_SEC2TICKS(wdd->timeout);
 150         u32 reg;
 151
 152         /*
 153          * Because the fields WDV and WDD must not be modified when the WDDIS
 154          * bit is set, so clear the WDDIS bit before writing the WDT_MR.
 155          */
 156         reg = wdt_read(wdt, AT91_WDT_MR);
 157         reg &= ~AT91_WDT_WDDIS;
 158         wdt_write(wdt, AT91_WDT_MR, reg);
 159
 160         wdt->mr |= AT91_WDT_SET_WDD(value);
 161         wdt->mr |= AT91_WDT_SET_WDV(value);
 162
 163         wdt_write(wdt, AT91_WDT_MR, wdt->mr);
 164
 165         return 0;
 166 }
 167
 168 static int sama5d4_wdt_probe(struct platform_device *pdev)
 169 {
 170         struct watchdog_device *wdd;
 171         struct sama5d4_wdt *wdt;
 172         struct resource *res;
 173         void __iomem *regs;
 174         u32 irq = 0;
 175         int ret;
 176
 177         wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
 178         if (!wdt)
 179                 return -ENOMEM;
 180
 181         wdd = &wdt->wdd;
 182         wdd->timeout = wdt_timeout;
 183         wdd->info = &sama5d4_wdt_info;
 184         wdd->ops = &sama5d4_wdt_ops;
 185         wdd->min_timeout = MIN_WDT_TIMEOUT;
 186         wdd->max_timeout = MAX_WDT_TIMEOUT;
 187
 188         watchdog_set_drvdata(wdd, wdt);
 189
 190         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 191         regs = devm_ioremap_resource(&pdev->dev, res);
 192         if (IS_ERR(regs))
 193                 return PTR_ERR(regs);
 194
 195         wdt->reg_base = regs;
 196
 197         if (pdev->dev.of_node) {
 198                 irq = irq_of_parse_and_map(pdev->dev.of_node, 0);
 199                 if (!irq)
 200                         dev_warn(&pdev->dev, "failed to get IRQ from DT\n");
 201
 202                 ret = of_sama5d4_wdt_init(pdev->dev.of_node, wdt);
 203                 if (ret)
 204                         return ret;
 205         }
 206
 207         if ((wdt->mr & AT91_WDT_WDFIEN) && irq) {
 208                 ret = devm_request_irq(&pdev->dev, irq, sama5d4_wdt_irq_handler,
 209                                        IRQF_SHARED | IRQF_IRQPOLL |
 210                                        IRQF_NO_SUSPEND, pdev->name, pdev);
 211                 if (ret) {
 212                         dev_err(&pdev->dev,
 213                                 "cannot register interrupt handler\n");
 214                         return ret;
 215                 }
 216         }
 217
 218         ret = watchdog_init_timeout(wdd, wdt_timeout, &pdev->dev);
 219         if (ret) {
 220                 dev_err(&pdev->dev, "unable to set timeout value\n");
 221                 return ret;
 222         }
 223
 224         ret = sama5d4_wdt_init(wdt);
 225         if (ret)
 226                 return ret;
 227
 228         watchdog_set_nowayout(wdd, nowayout);
 229
 230         ret = watchdog_register_device(wdd);
 231         if (ret) {
 232                 dev_err(&pdev->dev, "failed to register watchdog device\n");
 233                 return ret;
 234         }
 235
 236         platform_set_drvdata(pdev, wdt);
 237
 238         dev_info(&pdev->dev, "initialized (timeout = %d sec, nowayout = %d)\n",
 239                  wdt_timeout, nowayout);
 240
 241         return 0;
 242 }
 243
 244 static int sama5d4_wdt_remove(struct platform_device *pdev)
 245 {
 246         struct sama5d4_wdt *wdt = platform_get_drvdata(pdev);
 247
 248         sama5d4_wdt_stop(&wdt->wdd);
 249
 250         watchdog_unregister_device(&wdt->wdd);
 251
 252         return 0;
 253 }
 254
 255 static const struct of_device_id sama5d4_wdt_of_match[] = {
 256         { .compatible = "atmel,sama5d4-wdt", },
 257         { }
 258 };
 259 MODULE_DEVICE_TABLE(of, sama5d4_wdt_of_match);
 260
 261 #ifdef CONFIG_PM_SLEEP
 262 static int sama5d4_wdt_resume(struct device *dev)
 263 {
 264         struct sama5d4_wdt *wdt = dev_get_drvdata(dev);
 265
 266         wdt_write(wdt, AT91_WDT_MR, wdt->mr & ~AT91_WDT_WDDIS);
 267         if (wdt->mr & AT91_WDT_WDDIS)
 268                 wdt_write(wdt, AT91_WDT_MR, wdt->mr);
 269
 270         return 0;
 271 }
 272 #endif
 273
 274 static SIMPLE_DEV_PM_OPS(sama5d4_wdt_pm_ops, NULL,
 275                          sama5d4_wdt_resume);
 276
 277 static struct platform_driver sama5d4_wdt_driver = {
 278         .probe          = sama5d4_wdt_probe,
 279         .remove         = sama5d4_wdt_remove,
 280         .driver         = {
 281                 .name   = "sama5d4_wdt",
 282                 .pm     = &sama5d4_wdt_pm_ops,
 283                 .of_match_table = sama5d4_wdt_of_match,
 284         }
 285 };
 286 module_platform_driver(sama5d4_wdt_driver);
 287
 288 MODULE_AUTHOR("Atmel Corporation");
 289 MODULE_DESCRIPTION("Atmel SAMA5D4 Watchdog Timer driver");
 290 MODULE_LICENSE("GPL v2");