drivers/watchdog/mpc8xxx_wdt.c

   1 /*
   2  * mpc8xxx_wdt.c - MPC8xx/MPC83xx/MPC86xx watchdog userspace interface
   3  *
   4  * Authors: Dave Updegraff <dave@cray.org>
   5  *          Kumar Gala <galak@kernel.crashing.org>
   6  *              Attribution: from 83xx_wst: Florian Schirmer <jolt@tuxbox.org>
   7  *                              ..and from sc520_wdt
   8  * Copyright (c) 2008  MontaVista Software, Inc.
   9  *                     Anton Vorontsov <avorontsov@ru.mvista.com>
  10  *
  11  * Note: it appears that you can only actually ENABLE or DISABLE the thing
  12  * once after POR. Once enabled, you cannot disable, and vice versa.
  13  *
  14  * This program is free software; you can redistribute  it and/or modify it
  15  * under  the terms of  the GNU General  Public License as published by the
  16  * Free Software Foundation;  either version 2 of the  License, or (at your
  17  * option) any later version.
  18  */
  19
  20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  21
  22 #include <linux/fs.h>
  23 #include <linux/init.h>
  24 #include <linux/kernel.h>
  25 #include <linux/timer.h>
  26 #include <linux/of_address.h>
  27 #include <linux/of_platform.h>
  28 #include <linux/module.h>
  29 #include <linux/watchdog.h>
  30 #include <linux/io.h>
  31 #include <linux/uaccess.h>
  32 #include <sysdev/fsl_soc.h>
  33
  34 struct mpc8xxx_wdt {
  35         __be32 res0;
  36         __be32 swcrr; /* System watchdog control register */
  37 #define SWCRR_SWTC 0xFFFF0000 /* Software Watchdog Time Count. */
  38 #define SWCRR_SWEN 0x00000004 /* Watchdog Enable bit. */
  39 #define SWCRR_SWRI 0x00000002 /* Software Watchdog Reset/Interrupt Select bit.*/
  40 #define SWCRR_SWPR 0x00000001 /* Software Watchdog Counter Prescale bit. */
  41         __be32 swcnr; /* System watchdog count register */
  42         u8 res1[2];
  43         __be16 swsrr; /* System watchdog service register */
  44         u8 res2[0xF0];
  45 };
  46
  47 struct mpc8xxx_wdt_type {
  48         int prescaler;
  49         bool hw_enabled;
  50 };
  51
  52 struct mpc8xxx_wdt_ddata {
  53         struct mpc8xxx_wdt __iomem *base;
  54         struct watchdog_device wdd;
  55         struct timer_list timer;
  56         spinlock_t lock;
  57 };
  58
  59 static u16 timeout = 0xffff;
  60 module_param(timeout, ushort, 0);
  61 MODULE_PARM_DESC(timeout,
  62         "Watchdog timeout in ticks. (0<timeout<65536, default=65535)");
  63
  64 static bool reset = 1;
  65 module_param(reset, bool, 0);
  66 MODULE_PARM_DESC(reset,
  67         "Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset");
  68
  69 static bool nowayout = WATCHDOG_NOWAYOUT;
  70 module_param(nowayout, bool, 0);
  71 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
  72                  "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  73
  74 static void mpc8xxx_wdt_keepalive(struct mpc8xxx_wdt_ddata *ddata)
  75 {
  76         /* Ping the WDT */
  77         spin_lock(&ddata->lock);
  78         out_be16(&ddata->base->swsrr, 0x556c);
  79         out_be16(&ddata->base->swsrr, 0xaa39);
  80         spin_unlock(&ddata->lock);
  81 }
  82
  83 static void mpc8xxx_wdt_timer_ping(struct timer_list *t)
  84 {
  85         struct mpc8xxx_wdt_ddata *ddata = from_timer(ddata, t, timer);
  86
  87         mpc8xxx_wdt_keepalive(ddata);
  88         /* We're pinging it twice faster than needed, just to be sure. */
  89         mod_timer(&ddata->timer, jiffies + HZ * ddata->wdd.timeout / 2);
  90 }
  91
  92 static int mpc8xxx_wdt_start(struct watchdog_device *w)
  93 {
  94         struct mpc8xxx_wdt_ddata *ddata =
  95                 container_of(w, struct mpc8xxx_wdt_ddata, wdd);
  96
  97         u32 tmp = SWCRR_SWEN | SWCRR_SWPR;
  98
  99         /* Good, fire up the show */
 100         if (reset)
 101                 tmp |= SWCRR_SWRI;
 102
 103         tmp |= timeout << 16;
 104
 105         out_be32(&ddata->base->swcrr, tmp);
 106
 107         del_timer_sync(&ddata->timer);
 108
 109         return 0;
 110 }
 111
 112 static int mpc8xxx_wdt_ping(struct watchdog_device *w)
 113 {
 114         struct mpc8xxx_wdt_ddata *ddata =
 115                 container_of(w, struct mpc8xxx_wdt_ddata, wdd);
 116
 117         mpc8xxx_wdt_keepalive(ddata);
 118         return 0;
 119 }
 120
 121 static int mpc8xxx_wdt_stop(struct watchdog_device *w)
 122 {
 123         struct mpc8xxx_wdt_ddata *ddata =
 124                 container_of(w, struct mpc8xxx_wdt_ddata, wdd);
 125
 126         mod_timer(&ddata->timer, jiffies);
 127         return 0;
 128 }
 129
 130 static struct watchdog_info mpc8xxx_wdt_info = {
 131         .options = WDIOF_KEEPALIVEPING,
 132         .firmware_version = 1,
 133         .identity = "MPC8xxx",
 134 };
 135
 136 static struct watchdog_ops mpc8xxx_wdt_ops = {
 137         .owner = THIS_MODULE,
 138         .start = mpc8xxx_wdt_start,
 139         .ping = mpc8xxx_wdt_ping,
 140         .stop = mpc8xxx_wdt_stop,
 141 };
 142
 143 static int mpc8xxx_wdt_probe(struct platform_device *ofdev)
 144 {
 145         int ret;
 146         struct resource *res;
 147         const struct mpc8xxx_wdt_type *wdt_type;
 148         struct mpc8xxx_wdt_ddata *ddata;
 149         u32 freq = fsl_get_sys_freq();
 150         bool enabled;
 151         unsigned int timeout_sec;
 152
 153         wdt_type = of_device_get_match_data(&ofdev->dev);
 154         if (!wdt_type)
 155                 return -EINVAL;
 156
 157         if (!freq || freq == -1)
 158                 return -EINVAL;
 159
 160         ddata = devm_kzalloc(&ofdev->dev, sizeof(*ddata), GFP_KERNEL);
 161         if (!ddata)
 162                 return -ENOMEM;
 163
 164         res = platform_get_resource(ofdev, IORESOURCE_MEM, 0);
 165         ddata->base = devm_ioremap_resource(&ofdev->dev, res);
 166         if (IS_ERR(ddata->base))
 167                 return PTR_ERR(ddata->base);
 168
 169         enabled = in_be32(&ddata->base->swcrr) & SWCRR_SWEN;
 170         if (!enabled && wdt_type->hw_enabled) {
 171                 pr_info("could not be enabled in software\n");
 172                 return -ENODEV;
 173         }
 174
 175         spin_lock_init(&ddata->lock);
 176         timer_setup(&ddata->timer, mpc8xxx_wdt_timer_ping, 0);
 177
 178         ddata->wdd.info = &mpc8xxx_wdt_info,
 179         ddata->wdd.ops = &mpc8xxx_wdt_ops,
 180
 181         /* Calculate the timeout in seconds */
 182         timeout_sec = (timeout * wdt_type->prescaler) / freq;
 183
 184         ddata->wdd.timeout = timeout_sec;
 185
 186         watchdog_set_nowayout(&ddata->wdd, nowayout);
 187
 188         ret = watchdog_register_device(&ddata->wdd);
 189         if (ret) {
 190                 pr_err("cannot register watchdog device (err=%d)\n", ret);
 191                 return ret;
 192         }
 193
 194         pr_info("WDT driver for MPC8xxx initialized. mode:%s timeout=%d (%d seconds)\n",
 195                 reset ? "reset" : "interrupt", timeout, timeout_sec);
 196
 197         /*
 198          * If the watchdog was previously enabled or we're running on
 199          * MPC8xxx, we should ping the wdt from the kernel until the
 200          * userspace handles it.
 201          */
 202         if (enabled)
 203                 mod_timer(&ddata->timer, jiffies);
 204
 205         platform_set_drvdata(ofdev, ddata);
 206         return 0;
 207 }
 208
 209 static int mpc8xxx_wdt_remove(struct platform_device *ofdev)
 210 {
 211         struct mpc8xxx_wdt_ddata *ddata = platform_get_drvdata(ofdev);
 212
 213         pr_crit("Watchdog removed, expect the %s soon!\n",
 214                 reset ? "reset" : "machine check exception");
 215         del_timer_sync(&ddata->timer);
 216         watchdog_unregister_device(&ddata->wdd);
 217
 218         return 0;
 219 }
 220
 221 static const struct of_device_id mpc8xxx_wdt_match[] = {
 222         {
 223                 .compatible = "mpc83xx_wdt",
 224                 .data = &(struct mpc8xxx_wdt_type) {
 225                         .prescaler = 0x10000,
 226                 },
 227         },
 228         {
 229                 .compatible = "fsl,mpc8610-wdt",
 230                 .data = &(struct mpc8xxx_wdt_type) {
 231                         .prescaler = 0x10000,
 232                         .hw_enabled = true,
 233                 },
 234         },
 235         {
 236                 .compatible = "fsl,mpc823-wdt",
 237                 .data = &(struct mpc8xxx_wdt_type) {
 238                         .prescaler = 0x800,
 239                         .hw_enabled = true,
 240                 },
 241         },
 242         {},
 243 };
 244 MODULE_DEVICE_TABLE(of, mpc8xxx_wdt_match);
 245
 246 static struct platform_driver mpc8xxx_wdt_driver = {
 247         .probe          = mpc8xxx_wdt_probe,
 248         .remove         = mpc8xxx_wdt_remove,
 249         .driver = {
 250                 .name = "mpc8xxx_wdt",
 251                 .of_match_table = mpc8xxx_wdt_match,
 252         },
 253 };
 254
 255 static int __init mpc8xxx_wdt_init(void)
 256 {
 257         return platform_driver_register(&mpc8xxx_wdt_driver);
 258 }
 259 arch_initcall(mpc8xxx_wdt_init);
 260
 261 static void __exit mpc8xxx_wdt_exit(void)
 262 {
 263         platform_driver_unregister(&mpc8xxx_wdt_driver);
 264 }
 265 module_exit(mpc8xxx_wdt_exit);
 266
 267 MODULE_AUTHOR("Dave Updegraff, Kumar Gala");
 268 MODULE_DESCRIPTION("Driver for watchdog timer in MPC8xx/MPC83xx/MPC86xx "
 269                    "uProcessors");
 270 MODULE_LICENSE("GPL");