drivers/watchdog/orion_wdt.c

   1 /*
   2  * drivers/watchdog/orion_wdt.c
   3  *
   4  * Watchdog driver for Orion/Kirkwood processors
   5  *
   6  * Author: Sylver Bruneau <sylver.bruneau@googlemail.com>
   7  *
   8  * This file is licensed under  the terms of the GNU General Public
   9  * License version 2. This program is licensed "as is" without any
  10  * warranty of any kind, whether express or implied.
  11  */
  12
  13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14
  15 #include <linux/module.h>
  16 #include <linux/moduleparam.h>
  17 #include <linux/types.h>
  18 #include <linux/kernel.h>
  19 #include <linux/miscdevice.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/watchdog.h>
  22 #include <linux/init.h>
  23 #include <linux/io.h>
  24 #include <linux/spinlock.h>
  25 #include <linux/clk.h>
  26 #include <linux/err.h>
  27 #include <linux/of.h>
  28 #include <mach/bridge-regs.h>
  29
  30 /*
  31  * Watchdog timer block registers.
  32  */
  33 #define TIMER_CTRL              0x0000
  34 #define WDT_EN                  0x0010
  35 #define WDT_VAL                 0x0024
  36
  37 #define WDT_MAX_CYCLE_COUNT     0xffffffff
  38 #define WDT_IN_USE              0
  39 #define WDT_OK_TO_CLOSE         1
  40
  41 static bool nowayout = WATCHDOG_NOWAYOUT;
  42 static int heartbeat = -1;              /* module parameter (seconds) */
  43 static unsigned int wdt_max_duration;   /* (seconds) */
  44 static struct clk *clk;
  45 static unsigned int wdt_tclk;
  46 static void __iomem *wdt_reg;
  47 static DEFINE_SPINLOCK(wdt_lock);
  48
  49 static int orion_wdt_ping(struct watchdog_device *wdt_dev)
  50 {
  51         spin_lock(&wdt_lock);
  52
  53         /* Reload watchdog duration */
  54         writel(wdt_tclk * wdt_dev->timeout, wdt_reg + WDT_VAL);
  55
  56         spin_unlock(&wdt_lock);
  57         return 0;
  58 }
  59
  60 static int orion_wdt_start(struct watchdog_device *wdt_dev)
  61 {
  62         u32 reg;
  63
  64         spin_lock(&wdt_lock);
  65
  66         /* Set watchdog duration */
  67         writel(wdt_tclk * wdt_dev->timeout, wdt_reg + WDT_VAL);
  68
  69         /* Clear watchdog timer interrupt */
  70         reg = readl(BRIDGE_CAUSE);
  71         reg &= ~WDT_INT_REQ;
  72         writel(reg, BRIDGE_CAUSE);
  73
  74         /* Enable watchdog timer */
  75         reg = readl(wdt_reg + TIMER_CTRL);
  76         reg |= WDT_EN;
  77         writel(reg, wdt_reg + TIMER_CTRL);
  78
  79         /* Enable reset on watchdog */
  80         reg = readl(RSTOUTn_MASK);
  81         reg |= WDT_RESET_OUT_EN;
  82         writel(reg, RSTOUTn_MASK);
  83
  84         spin_unlock(&wdt_lock);
  85         return 0;
  86 }
  87
  88 static int orion_wdt_stop(struct watchdog_device *wdt_dev)
  89 {
  90         u32 reg;
  91
  92         spin_lock(&wdt_lock);
  93
  94         /* Disable reset on watchdog */
  95         reg = readl(RSTOUTn_MASK);
  96         reg &= ~WDT_RESET_OUT_EN;
  97         writel(reg, RSTOUTn_MASK);
  98
  99         /* Disable watchdog timer */
 100         reg = readl(wdt_reg + TIMER_CTRL);
 101         reg &= ~WDT_EN;
 102         writel(reg, wdt_reg + TIMER_CTRL);
 103
 104         spin_unlock(&wdt_lock);
 105         return 0;
 106 }
 107
 108 static unsigned int orion_wdt_get_timeleft(struct watchdog_device *wdt_dev)
 109 {
 110         unsigned int time_left;
 111
 112         spin_lock(&wdt_lock);
 113         time_left = readl(wdt_reg + WDT_VAL) / wdt_tclk;
 114         spin_unlock(&wdt_lock);
 115
 116         return time_left;
 117 }
 118
 119 static int orion_wdt_set_timeout(struct watchdog_device *wdt_dev,
 120                                  unsigned int timeout)
 121 {
 122         wdt_dev->timeout = timeout;
 123         return 0;
 124 }
 125
 126 static const struct watchdog_info orion_wdt_info = {
 127         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 128         .identity = "Orion Watchdog",
 129 };
 130
 131 static const struct watchdog_ops orion_wdt_ops = {
 132         .owner = THIS_MODULE,
 133         .start = orion_wdt_start,
 134         .stop = orion_wdt_stop,
 135         .ping = orion_wdt_ping,
 136         .set_timeout = orion_wdt_set_timeout,
 137         .get_timeleft = orion_wdt_get_timeleft,
 138 };
 139
 140 static struct watchdog_device orion_wdt = {
 141         .info = &orion_wdt_info,
 142         .ops = &orion_wdt_ops,
 143 };
 144
 145 static int orion_wdt_probe(struct platform_device *pdev)
 146 {
 147         struct resource *res;
 148         int ret;
 149
 150         clk = devm_clk_get(&pdev->dev, NULL);
 151         if (IS_ERR(clk)) {
 152                 dev_err(&pdev->dev, "Orion Watchdog missing clock\n");
 153                 return -ENODEV;
 154         }
 155         clk_prepare_enable(clk);
 156         wdt_tclk = clk_get_rate(clk);
 157
 158         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 159         if (!res)
 160                 return -ENODEV;
 161         wdt_reg = devm_ioremap(&pdev->dev, res->start, resource_size(res));
 162         if (!wdt_reg)
 163                 return -ENOMEM;
 164
 165         wdt_max_duration = WDT_MAX_CYCLE_COUNT / wdt_tclk;
 166
 167         if ((heartbeat < 1) || (heartbeat > wdt_max_duration))
 168                 heartbeat = wdt_max_duration;
 169
 170         orion_wdt.timeout = heartbeat;
 171         orion_wdt.min_timeout = 1;
 172         orion_wdt.max_timeout = wdt_max_duration;
 173
 174         watchdog_set_nowayout(&orion_wdt, nowayout);
 175         ret = watchdog_register_device(&orion_wdt);
 176         if (ret) {
 177                 clk_disable_unprepare(clk);
 178                 return ret;
 179         }
 180
 181         pr_info("Initial timeout %d sec%s\n",
 182                 heartbeat, nowayout ? ", nowayout" : "");
 183         return 0;
 184 }
 185
 186 static int orion_wdt_remove(struct platform_device *pdev)
 187 {
 188         watchdog_unregister_device(&orion_wdt);
 189         clk_disable_unprepare(clk);
 190         return 0;
 191 }
 192
 193 static void orion_wdt_shutdown(struct platform_device *pdev)
 194 {
 195         orion_wdt_stop(&orion_wdt);
 196 }
 197
 198 static const struct of_device_id orion_wdt_of_match_table[] = {
 199         { .compatible = "marvell,orion-wdt", },
 200         {},
 201 };
 202 MODULE_DEVICE_TABLE(of, orion_wdt_of_match_table);
 203
 204 static struct platform_driver orion_wdt_driver = {
 205         .probe          = orion_wdt_probe,
 206         .remove         = orion_wdt_remove,
 207         .shutdown       = orion_wdt_shutdown,
 208         .driver         = {
 209                 .owner  = THIS_MODULE,
 210                 .name   = "orion_wdt",
 211                 .of_match_table = of_match_ptr(orion_wdt_of_match_table),
 212         },
 213 };
 214
 215 module_platform_driver(orion_wdt_driver);
 216
 217 MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>");
 218 MODULE_DESCRIPTION("Orion Processor Watchdog");
 219
 220 module_param(heartbeat, int, 0);
 221 MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds");
 222
 223 module_param(nowayout, bool, 0);
 224 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
 225                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 226
 227 MODULE_LICENSE("GPL");
 228 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);