linux/drivers/watchdog/orion_wdt.c
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   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
  44static bool nowayout = WATCHDOG_NOWAYOUT;
  45static int heartbeat = -1;              /* module parameter (seconds) */
  46static unsigned int wdt_max_duration;   /* (seconds) */
  47static struct clk *clk;
  48static unsigned int wdt_tclk;
  49static void __iomem *wdt_reg;
  50static DEFINE_SPINLOCK(wdt_lock);
  51
  52static 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
  63static 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
  89static 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
 109static 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
 120static 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
 127static const struct watchdog_info orion_wdt_info = {
 128        .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 129        .identity = "Orion Watchdog",
 130};
 131
 132static 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
 141static struct watchdog_device orion_wdt = {
 142        .info = &orion_wdt_info,
 143        .ops = &orion_wdt_ops,
 144        .min_timeout = 1,
 145};
 146
 147static 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
 185static 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
 192static void orion_wdt_shutdown(struct platform_device *pdev)
 193{
 194        orion_wdt_stop(&orion_wdt);
 195}
 196
 197static const struct of_device_id orion_wdt_of_match_table[] = {
 198        { .compatible = "marvell,orion-wdt", },
 199        {},
 200};
 201MODULE_DEVICE_TABLE(of, orion_wdt_of_match_table);
 202
 203static 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 = of_match_ptr(orion_wdt_of_match_table),
 211        },
 212};
 213
 214module_platform_driver(orion_wdt_driver);
 215
 216MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>");
 217MODULE_DESCRIPTION("Orion Processor Watchdog");
 218
 219module_param(heartbeat, int, 0);
 220MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds");
 221
 222module_param(nowayout, bool, 0);
 223MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
 224                                __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 225
 226MODULE_LICENSE("GPL");
 227MODULE_ALIAS("platform:orion_wdt");
 228MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 229
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