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 #define WDT_RESET_OUT_EN        BIT(1)
  42 #define WDT_INT_REQ             BIT(3)
  43
  44 static bool nowayout = WATCHDOG_NOWAYOUT;
  45 static int heartbeat = -1;              /* module parameter (seconds) */
  46 static unsigned int wdt_max_duration;   /* (seconds) */
  47 static struct clk *clk;
  48 static unsigned int wdt_tclk;
  49 static void __iomem *wdt_reg;
  50 static DEFINE_SPINLOCK(wdt_lock);
  51
  52 static int orion_wdt_ping(struct watchdog_device *wdt_dev)
  53 {
  54         spin_lock(&wdt_lock);
  55
  56         /* Reload watchdog duration */
  57         writel(wdt_tclk * wdt_dev->timeout, wdt_reg + WDT_VAL);
  58
  59         spin_unlock(&wdt_lock);
  60         return 0;
  61 }
  62
  63 static int orion_wdt_start(struct watchdog_device *wdt_dev)
  64 {
  65         u32 reg;
  66
  67         spin_lock(&wdt_lock);
  68
  69         /* Set watchdog duration */
  70         writel(wdt_tclk * wdt_dev->timeout, wdt_reg + WDT_VAL);
  71
  72         /* Clear watchdog timer interrupt */
  73         writel(~WDT_INT_REQ, BRIDGE_CAUSE);
  74
  75         /* Enable watchdog timer */
  76         reg = readl(wdt_reg + TIMER_CTRL);
  77         reg |= WDT_EN;
  78         writel(reg, wdt_reg + TIMER_CTRL);
  79
  80         /* Enable reset on watchdog */
  81         reg = readl(RSTOUTn_MASK);
  82         reg |= WDT_RESET_OUT_EN;
  83         writel(reg, RSTOUTn_MASK);
  84
  85         spin_unlock(&wdt_lock);
  86         return 0;
  87 }
  88
  89 static int orion_wdt_stop(struct watchdog_device *wdt_dev)
  90 {
  91         u32 reg;
  92
  93         spin_lock(&wdt_lock);
  94
  95         /* Disable reset on watchdog */
  96         reg = readl(RSTOUTn_MASK);
  97         reg &= ~WDT_RESET_OUT_EN;
  98         writel(reg, RSTOUTn_MASK);
  99
 100         /* Disable watchdog timer */
 101         reg = readl(wdt_reg + TIMER_CTRL);
 102         reg &= ~WDT_EN;
 103         writel(reg, wdt_reg + TIMER_CTRL);
 104
 105         spin_unlock(&wdt_lock);
 106         return 0;
 107 }
 108
 109 static unsigned int orion_wdt_get_timeleft(struct watchdog_device *wdt_dev)
 110 {
 111         unsigned int time_left;
 112
 113         spin_lock(&wdt_lock);
 114         time_left = readl(wdt_reg + WDT_VAL) / wdt_tclk;
 115         spin_unlock(&wdt_lock);
 116
 117         return time_left;
 118 }
 119
 120 static int orion_wdt_set_timeout(struct watchdog_device *wdt_dev,
 121                                  unsigned int timeout)
 122 {
 123         wdt_dev->timeout = timeout;
 124         return 0;
 125 }
 126
 127 static const struct watchdog_info orion_wdt_info = {
 128         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 129         .identity = "Orion Watchdog",
 130 };
 131
 132 static const struct watchdog_ops orion_wdt_ops = {
 133         .owner = THIS_MODULE,
 134         .start = orion_wdt_start,
 135         .stop = orion_wdt_stop,
 136         .ping = orion_wdt_ping,
 137         .set_timeout = orion_wdt_set_timeout,
 138         .get_timeleft = orion_wdt_get_timeleft,
 139 };
 140
 141 static struct watchdog_device orion_wdt = {
 142         .info = &orion_wdt_info,
 143         .ops = &orion_wdt_ops,
 144         .min_timeout = 1,
 145 };
 146
 147 static int orion_wdt_probe(struct platform_device *pdev)
 148 {
 149         struct resource *res;
 150         int ret;
 151
 152         clk = devm_clk_get(&pdev->dev, NULL);
 153         if (IS_ERR(clk)) {
 154                 dev_err(&pdev->dev, "Orion Watchdog missing clock\n");
 155                 return -ENODEV;
 156         }
 157         clk_prepare_enable(clk);
 158         wdt_tclk = clk_get_rate(clk);
 159
 160         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 161         if (!res)
 162                 return -ENODEV;
 163         wdt_reg = devm_ioremap(&pdev->dev, res->start, resource_size(res));
 164         if (!wdt_reg)
 165                 return -ENOMEM;
 166
 167         wdt_max_duration = WDT_MAX_CYCLE_COUNT / wdt_tclk;
 168
 169         orion_wdt.timeout = wdt_max_duration;
 170         orion_wdt.max_timeout = wdt_max_duration;
 171         watchdog_init_timeout(&orion_wdt, heartbeat, &pdev->dev);
 172
 173         watchdog_set_nowayout(&orion_wdt, nowayout);
 174         ret = watchdog_register_device(&orion_wdt);
 175         if (ret) {
 176                 clk_disable_unprepare(clk);
 177                 return ret;
 178         }
 179
 180         pr_info("Initial timeout %d sec%s\n",
 181                 orion_wdt.timeout, nowayout ? ", nowayout" : "");
 182         return 0;
 183 }
 184
 185 static int orion_wdt_remove(struct platform_device *pdev)
 186 {
 187         watchdog_unregister_device(&orion_wdt);
 188         clk_disable_unprepare(clk);
 189         return 0;
 190 }
 191
 192 static void orion_wdt_shutdown(struct platform_device *pdev)
 193 {
 194         orion_wdt_stop(&orion_wdt);
 195 }
 196
 197 static const struct of_device_id orion_wdt_of_match_table[] = {
 198         { .compatible = "marvell,orion-wdt", },
 199         {},
 200 };
 201 MODULE_DEVICE_TABLE(of, orion_wdt_of_match_table);
 202
 203 static struct platform_driver orion_wdt_driver = {
 204         .probe          = orion_wdt_probe,
 205         .remove         = orion_wdt_remove,
 206         .shutdown       = orion_wdt_shutdown,
 207         .driver         = {
 208                 .owner  = THIS_MODULE,
 209                 .name   = "orion_wdt",
 210                 .of_match_table = orion_wdt_of_match_table,
 211         },
 212 };
 213
 214 module_platform_driver(orion_wdt_driver);
 215
 216 MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>");
 217 MODULE_DESCRIPTION("Orion Processor Watchdog");
 218
 219 module_param(heartbeat, int, 0);
 220 MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds");
 221
 222 module_param(nowayout, bool, 0);
 223 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
 224                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 225
 226 MODULE_LICENSE("GPL");
 227 MODULE_ALIAS("platform:orion_wdt");