linux/drivers/watchdog/rm9k_wdt.c
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   1/*
   2 *  Watchdog implementation for GPI h/w found on PMC-Sierra RM9xxx
   3 *  chips.
   4 *
   5 *  Copyright (C) 2004 by Basler Vision Technologies AG
   6 *  Author: Thomas Koeller <thomas.koeller@baslerweb.com>
   7 *
   8 *  This program is free software; you can redistribute it and/or modify
   9 *  it under the terms of the GNU General Public License as published by
  10 *  the Free Software Foundation; either version 2 of the License, or
  11 *  (at your option) any later version.
  12 *
  13 *  This program is distributed in the hope that it will be useful,
  14 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 *  GNU General Public License for more details.
  17 *
  18 *  You should have received a copy of the GNU General Public License
  19 *  along with this program; if not, write to the Free Software
  20 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21 */
  22
  23#include <linux/platform_device.h>
  24#include <linux/module.h>
  25#include <linux/moduleparam.h>
  26#include <linux/interrupt.h>
  27#include <linux/fs.h>
  28#include <linux/reboot.h>
  29#include <linux/notifier.h>
  30#include <linux/miscdevice.h>
  31#include <linux/watchdog.h>
  32#include <linux/io.h>
  33#include <linux/uaccess.h>
  34#include <asm/atomic.h>
  35#include <asm/processor.h>
  36#include <asm/system.h>
  37#include <asm/rm9k-ocd.h>
  38
  39#include <rm9k_wdt.h>
  40
  41
  42#define CLOCK                  125000000
  43#define MAX_TIMEOUT_SECONDS    32
  44#define CPCCR                  0x0080
  45#define CPGIG1SR               0x0044
  46#define CPGIG1ER               0x0054
  47
  48
  49/* Function prototypes */
  50static irqreturn_t wdt_gpi_irqhdl(int, void *);
  51static void wdt_gpi_start(void);
  52static void wdt_gpi_stop(void);
  53static void wdt_gpi_set_timeout(unsigned int);
  54static int wdt_gpi_open(struct inode *, struct file *);
  55static int wdt_gpi_release(struct inode *, struct file *);
  56static ssize_t wdt_gpi_write(struct file *, const char __user *, size_t,
  57                                                                loff_t *);
  58static long wdt_gpi_ioctl(struct file *, unsigned int, unsigned long);
  59static int wdt_gpi_notify(struct notifier_block *, unsigned long, void *);
  60static const struct resource *wdt_gpi_get_resource(struct platform_device *,
  61                                                const char *, unsigned int);
  62static int __init wdt_gpi_probe(struct device *);
  63static int __exit wdt_gpi_remove(struct device *);
  64
  65
  66static const char wdt_gpi_name[] = "wdt_gpi";
  67static atomic_t opencnt;
  68static int expect_close;
  69static int locked;
  70
  71
  72/* These are set from device resources */
  73static void __iomem *wd_regs;
  74static unsigned int wd_irq, wd_ctr;
  75
  76
  77/* Module arguments */
  78static int timeout = MAX_TIMEOUT_SECONDS;
  79module_param(timeout, int, 0444);
  80MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
  81
  82static unsigned long resetaddr = 0xbffdc200;
  83module_param(resetaddr, ulong, 0444);
  84MODULE_PARM_DESC(resetaddr, "Address to write to to force a reset");
  85
  86static unsigned long flagaddr = 0xbffdc104;
  87module_param(flagaddr, ulong, 0444);
  88MODULE_PARM_DESC(flagaddr, "Address to write to boot flags to");
  89
  90static int powercycle;
  91module_param(powercycle, bool, 0444);
  92MODULE_PARM_DESC(powercycle, "Cycle power if watchdog expires");
  93
  94static int nowayout = WATCHDOG_NOWAYOUT;
  95module_param(nowayout, bool, 0444);
  96MODULE_PARM_DESC(nowayout, "Watchdog cannot be disabled once started");
  97
  98
  99/* Kernel interfaces */
 100static const struct file_operations fops = {
 101        .owner          = THIS_MODULE,
 102        .open           = wdt_gpi_open,
 103        .release        = wdt_gpi_release,
 104        .write          = wdt_gpi_write,
 105        .unlocked_ioctl = wdt_gpi_ioctl,
 106};
 107
 108static struct miscdevice miscdev = {
 109        .minor          = WATCHDOG_MINOR,
 110        .name           = wdt_gpi_name,
 111        .fops           = &fops,
 112};
 113
 114static struct notifier_block wdt_gpi_shutdown = {
 115        .notifier_call  = wdt_gpi_notify,
 116};
 117
 118
 119/* Interrupt handler */
 120static irqreturn_t wdt_gpi_irqhdl(int irq, void *ctxt)
 121{
 122        if (!unlikely(__raw_readl(wd_regs + 0x0008) & 0x1))
 123                return IRQ_NONE;
 124        __raw_writel(0x1, wd_regs + 0x0008);
 125
 126
 127        printk(KERN_CRIT "%s: watchdog expired - resetting system\n",
 128                wdt_gpi_name);
 129
 130        *(volatile char *) flagaddr |= 0x01;
 131        *(volatile char *) resetaddr = powercycle ? 0x01 : 0x2;
 132        iob();
 133        while (1)
 134                cpu_relax();
 135}
 136
 137
 138/* Watchdog functions */
 139static void wdt_gpi_start(void)
 140{
 141        u32 reg;
 142
 143        lock_titan_regs();
 144        reg = titan_readl(CPGIG1ER);
 145        titan_writel(reg | (0x100 << wd_ctr), CPGIG1ER);
 146        iob();
 147        unlock_titan_regs();
 148}
 149
 150static void wdt_gpi_stop(void)
 151{
 152        u32 reg;
 153
 154        lock_titan_regs();
 155        reg = titan_readl(CPCCR) & ~(0xf << (wd_ctr * 4));
 156        titan_writel(reg, CPCCR);
 157        reg = titan_readl(CPGIG1ER);
 158        titan_writel(reg & ~(0x100 << wd_ctr), CPGIG1ER);
 159        iob();
 160        unlock_titan_regs();
 161}
 162
 163static void wdt_gpi_set_timeout(unsigned int to)
 164{
 165        u32 reg;
 166        const u32 wdval = (to * CLOCK) & ~0x0000000f;
 167
 168        lock_titan_regs();
 169        reg = titan_readl(CPCCR) & ~(0xf << (wd_ctr * 4));
 170        titan_writel(reg, CPCCR);
 171        wmb();
 172        __raw_writel(wdval, wd_regs + 0x0000);
 173        wmb();
 174        titan_writel(reg | (0x2 << (wd_ctr * 4)), CPCCR);
 175        wmb();
 176        titan_writel(reg | (0x5 << (wd_ctr * 4)), CPCCR);
 177        iob();
 178        unlock_titan_regs();
 179}
 180
 181
 182/* /dev/watchdog operations */
 183static int wdt_gpi_open(struct inode *inode, struct file *file)
 184{
 185        int res;
 186
 187        if (unlikely(atomic_dec_if_positive(&opencnt) < 0))
 188                return -EBUSY;
 189
 190        expect_close = 0;
 191        if (locked) {
 192                module_put(THIS_MODULE);
 193                free_irq(wd_irq, &miscdev);
 194                locked = 0;
 195        }
 196
 197        res = request_irq(wd_irq, wdt_gpi_irqhdl, IRQF_SHARED | IRQF_DISABLED,
 198                          wdt_gpi_name, &miscdev);
 199        if (unlikely(res))
 200                return res;
 201
 202        wdt_gpi_set_timeout(timeout);
 203        wdt_gpi_start();
 204
 205        printk(KERN_INFO "%s: watchdog started, timeout = %u seconds\n",
 206                wdt_gpi_name, timeout);
 207        return nonseekable_open(inode, file);
 208}
 209
 210static int wdt_gpi_release(struct inode *inode, struct file *file)
 211{
 212        if (nowayout) {
 213                printk(KERN_INFO "%s: no way out - watchdog left running\n",
 214                        wdt_gpi_name);
 215                __module_get(THIS_MODULE);
 216                locked = 1;
 217        } else {
 218                if (expect_close) {
 219                        wdt_gpi_stop();
 220                        free_irq(wd_irq, &miscdev);
 221                        printk(KERN_INFO "%s: watchdog stopped\n",
 222                                                        wdt_gpi_name);
 223                } else {
 224                        printk(KERN_CRIT "%s: unexpected close() -"
 225                                " watchdog left running\n",
 226                                wdt_gpi_name);
 227                        wdt_gpi_set_timeout(timeout);
 228                        __module_get(THIS_MODULE);
 229                        locked = 1;
 230                }
 231        }
 232
 233        atomic_inc(&opencnt);
 234        return 0;
 235}
 236
 237static ssize_t wdt_gpi_write(struct file *f, const char __user *d, size_t s,
 238                                                                loff_t *o)
 239{
 240        char val;
 241
 242        wdt_gpi_set_timeout(timeout);
 243        expect_close = (s > 0) && !get_user(val, d) && (val == 'V');
 244        return s ? 1 : 0;
 245}
 246
 247static long wdt_gpi_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
 248{
 249        long res = -ENOTTY;
 250        const long size = _IOC_SIZE(cmd);
 251        int stat;
 252        void __user *argp = (void __user *)arg;
 253        static struct watchdog_info wdinfo = {
 254                .identity               = "RM9xxx/GPI watchdog",
 255                .firmware_version       = 0,
 256                .options                = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING
 257        };
 258
 259        if (unlikely(_IOC_TYPE(cmd) != WATCHDOG_IOCTL_BASE))
 260                return -ENOTTY;
 261
 262        if ((_IOC_DIR(cmd) & _IOC_READ)
 263            && !access_ok(VERIFY_WRITE, arg, size))
 264                return -EFAULT;
 265
 266        if ((_IOC_DIR(cmd) & _IOC_WRITE)
 267            && !access_ok(VERIFY_READ, arg, size))
 268                return -EFAULT;
 269
 270        expect_close = 0;
 271
 272        switch (cmd) {
 273        case WDIOC_GETSUPPORT:
 274                wdinfo.options = nowayout ?
 275                        WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING :
 276                        WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
 277                        WDIOF_MAGICCLOSE;
 278                res = __copy_to_user(argp, &wdinfo, size) ?  -EFAULT : size;
 279                break;
 280
 281        case WDIOC_GETSTATUS:
 282                break;
 283
 284        case WDIOC_GETBOOTSTATUS:
 285                stat = (*(volatile char *) flagaddr & 0x01)
 286                        ? WDIOF_CARDRESET : 0;
 287                res = __copy_to_user(argp, &stat, size) ?
 288                        -EFAULT : size;
 289                break;
 290
 291        case WDIOC_SETOPTIONS:
 292                break;
 293
 294        case WDIOC_KEEPALIVE:
 295                wdt_gpi_set_timeout(timeout);
 296                res = size;
 297                break;
 298
 299        case WDIOC_SETTIMEOUT:
 300                {
 301                        int val;
 302                        if (unlikely(__copy_from_user(&val, argp, size))) {
 303                                res = -EFAULT;
 304                                break;
 305                        }
 306
 307                        if (val > MAX_TIMEOUT_SECONDS)
 308                                val = MAX_TIMEOUT_SECONDS;
 309                        timeout = val;
 310                        wdt_gpi_set_timeout(val);
 311                        res = size;
 312                        printk(KERN_INFO "%s: timeout set to %u seconds\n",
 313                                wdt_gpi_name, timeout);
 314                }
 315                break;
 316
 317        case WDIOC_GETTIMEOUT:
 318                res = __copy_to_user(argp, &timeout, size) ?
 319                        -EFAULT : size;
 320                break;
 321        }
 322
 323        return res;
 324}
 325
 326
 327/* Shutdown notifier */
 328static int wdt_gpi_notify(struct notifier_block *this, unsigned long code,
 329                          void *unused)
 330{
 331        if (code == SYS_DOWN || code == SYS_HALT)
 332                wdt_gpi_stop();
 333
 334        return NOTIFY_DONE;
 335}
 336
 337
 338/* Init & exit procedures */
 339static const struct resource *wdt_gpi_get_resource(struct platform_device *pdv,
 340                                        const char *name, unsigned int type)
 341{
 342        char buf[80];
 343        if (snprintf(buf, sizeof buf, "%s_0", name) >= sizeof buf)
 344                return NULL;
 345        return platform_get_resource_byname(pdv, type, buf);
 346}
 347
 348/* No hotplugging on the platform bus - use __init */
 349static int __init wdt_gpi_probe(struct device *dev)
 350{
 351        int res;
 352        struct platform_device * const pdv = to_platform_device(dev);
 353        const struct resource
 354                * const rr = wdt_gpi_get_resource(pdv, WDT_RESOURCE_REGS,
 355                                                  IORESOURCE_MEM),
 356                * const ri = wdt_gpi_get_resource(pdv, WDT_RESOURCE_IRQ,
 357                                                  IORESOURCE_IRQ),
 358                * const rc = wdt_gpi_get_resource(pdv, WDT_RESOURCE_COUNTER,
 359                                                  0);
 360
 361        if (unlikely(!rr || !ri || !rc))
 362                return -ENXIO;
 363
 364        wd_regs = ioremap_nocache(rr->start, rr->end + 1 - rr->start);
 365        if (unlikely(!wd_regs))
 366                return -ENOMEM;
 367        wd_irq = ri->start;
 368        wd_ctr = rc->start;
 369        res = misc_register(&miscdev);
 370        if (res)
 371                iounmap(wd_regs);
 372        else
 373                register_reboot_notifier(&wdt_gpi_shutdown);
 374        return res;
 375}
 376
 377static int __exit wdt_gpi_remove(struct device *dev)
 378{
 379        int res;
 380
 381        unregister_reboot_notifier(&wdt_gpi_shutdown);
 382        res = misc_deregister(&miscdev);
 383        iounmap(wd_regs);
 384        wd_regs = NULL;
 385        return res;
 386}
 387
 388
 389/* Device driver init & exit */
 390static struct device_driver wdt_gpi_driver = {
 391        .name           = (char *) wdt_gpi_name,
 392        .bus            = &platform_bus_type,
 393        .owner          = THIS_MODULE,
 394        .probe          = wdt_gpi_probe,
 395        .remove         = __exit_p(wdt_gpi_remove),
 396        .shutdown       = NULL,
 397        .suspend        = NULL,
 398        .resume         = NULL,
 399};
 400
 401static int __init wdt_gpi_init_module(void)
 402{
 403        atomic_set(&opencnt, 1);
 404        if (timeout > MAX_TIMEOUT_SECONDS)
 405                timeout = MAX_TIMEOUT_SECONDS;
 406        return driver_register(&wdt_gpi_driver);
 407}
 408
 409static void __exit wdt_gpi_cleanup_module(void)
 410{
 411        driver_unregister(&wdt_gpi_driver);
 412}
 413
 414module_init(wdt_gpi_init_module);
 415module_exit(wdt_gpi_cleanup_module);
 416
 417MODULE_AUTHOR("Thomas Koeller <thomas.koeller@baslerweb.com>");
 418MODULE_DESCRIPTION("Basler eXcite watchdog driver for gpi devices");
 419MODULE_VERSION("0.1");
 420MODULE_LICENSE("GPL");
 421MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 422
 423