drivers/watchdog/omap_wdt.c

   1 /*
   2  * linux/drivers/watchdog/omap_wdt.c
   3  *
   4  * Watchdog driver for the TI OMAP 16xx & 24xx/34xx 32KHz (non-secure) watchdog
   5  *
   6  * Author: MontaVista Software, Inc.
   7  *       <gdavis@mvista.com> or <source@mvista.com>
   8  *
   9  * 2003 (c) MontaVista Software, Inc. This file is licensed under the
  10  * terms of the GNU General Public License version 2. This program is
  11  * licensed "as is" without any warranty of any kind, whether express
  12  * or implied.
  13  *
  14  * History:
  15  *
  16  * 20030527: George G. Davis <gdavis@mvista.com>
  17  *      Initially based on linux-2.4.19-rmk7-pxa1/drivers/char/sa1100_wdt.c
  18  *      (c) Copyright 2000 Oleg Drokin <green@crimea.edu>
  19  *      Based on SoftDog driver by Alan Cox <alan@redhat.com>
  20  *
  21  * Copyright (c) 2004 Texas Instruments.
  22  *      1. Modified to support OMAP1610 32-KHz watchdog timer
  23  *      2. Ported to 2.6 kernel
  24  *
  25  * Copyright (c) 2005 David Brownell
  26  *      Use the driver model and standard identifiers; handle bigger timeouts.
  27  */
  28
  29 #include <linux/module.h>
  30 #include <linux/types.h>
  31 #include <linux/kernel.h>
  32 #include <linux/fs.h>
  33 #include <linux/mm.h>
  34 #include <linux/miscdevice.h>
  35 #include <linux/watchdog.h>
  36 #include <linux/reboot.h>
  37 #include <linux/init.h>
  38 #include <linux/err.h>
  39 #include <linux/platform_device.h>
  40 #include <linux/moduleparam.h>
  41 #include <linux/clk.h>
  42
  43 #include <linux/bitops.h>
  44 #include <linux/io.h>
  45 #include <linux/uaccess.h>
  46 #include <mach/hardware.h>
  47 #include <mach/prcm.h>
  48
  49 #include "omap_wdt.h"
  50
  51 static struct platform_device *omap_wdt_dev;
  52
  53 static unsigned timer_margin;
  54 module_param(timer_margin, uint, 0);
  55 MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)");
  56
  57 static unsigned int wdt_trgr_pattern = 0x1234;
  58 static spinlock_t wdt_lock;
  59
  60 struct omap_wdt_dev {
  61         void __iomem    *base;          /* physical */
  62         struct device   *dev;
  63         int             omap_wdt_users;
  64         struct clk      *armwdt_ck;
  65         struct clk      *mpu_wdt_ick;
  66         struct clk      *mpu_wdt_fck;
  67         struct resource *mem;
  68         struct miscdevice omap_wdt_miscdev;
  69 };
  70
  71 static void omap_wdt_ping(struct omap_wdt_dev *wdev)
  72 {
  73         void __iomem    *base = wdev->base;
  74         /* wait for posted write to complete */
  75         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x08)
  76                 cpu_relax();
  77         wdt_trgr_pattern = ~wdt_trgr_pattern;
  78         __raw_writel(wdt_trgr_pattern, (base + OMAP_WATCHDOG_TGR));
  79         /* wait for posted write to complete */
  80         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x08)
  81                 cpu_relax();
  82         /* reloaded WCRR from WLDR */
  83 }
  84
  85 static void omap_wdt_enable(struct omap_wdt_dev *wdev)
  86 {
  87         void __iomem *base;
  88         base = wdev->base;
  89         /* Sequence to enable the watchdog */
  90         __raw_writel(0xBBBB, base + OMAP_WATCHDOG_SPR);
  91         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x10)
  92                 cpu_relax();
  93         __raw_writel(0x4444, base + OMAP_WATCHDOG_SPR);
  94         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x10)
  95                 cpu_relax();
  96 }
  97
  98 static void omap_wdt_disable(struct omap_wdt_dev *wdev)
  99 {
 100         void __iomem *base;
 101         base = wdev->base;
 102         /* sequence required to disable watchdog */
 103         __raw_writel(0xAAAA, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */
 104         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x10)
 105                 cpu_relax();
 106         __raw_writel(0x5555, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */
 107         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x10)
 108                 cpu_relax();
 109 }
 110
 111 static void omap_wdt_adjust_timeout(unsigned new_timeout)
 112 {
 113         if (new_timeout < TIMER_MARGIN_MIN)
 114                 new_timeout = TIMER_MARGIN_DEFAULT;
 115         if (new_timeout > TIMER_MARGIN_MAX)
 116                 new_timeout = TIMER_MARGIN_MAX;
 117         timer_margin = new_timeout;
 118 }
 119
 120 static void omap_wdt_set_timeout(struct omap_wdt_dev *wdev)
 121 {
 122         u32 pre_margin = GET_WLDR_VAL(timer_margin);
 123         void __iomem *base;
 124         base = wdev->base;
 125
 126         /* just count up at 32 KHz */
 127         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x04)
 128                 cpu_relax();
 129         __raw_writel(pre_margin, base + OMAP_WATCHDOG_LDR);
 130         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x04)
 131                 cpu_relax();
 132 }
 133
 134 /*
 135  *      Allow only one task to hold it open
 136  */
 137
 138 static int omap_wdt_open(struct inode *inode, struct file *file)
 139 {
 140         struct omap_wdt_dev *wdev;
 141         void __iomem *base;
 142         wdev = platform_get_drvdata(omap_wdt_dev);
 143         base = wdev->base;
 144         if (test_and_set_bit(1, (unsigned long *)&(wdev->omap_wdt_users)))
 145                 return -EBUSY;
 146
 147         if (cpu_is_omap16xx())
 148                 clk_enable(wdev->armwdt_ck);    /* Enable the clock */
 149
 150         if (cpu_is_omap24xx() || cpu_is_omap34xx()) {
 151                 clk_enable(wdev->mpu_wdt_ick);    /* Enable the interface clock */
 152                 clk_enable(wdev->mpu_wdt_fck);    /* Enable the functional clock */
 153         }
 154
 155         /* initialize prescaler */
 156         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x01)
 157                 cpu_relax();
 158         __raw_writel((1 << 5) | (PTV << 2), base + OMAP_WATCHDOG_CNTRL);
 159         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x01)
 160                 cpu_relax();
 161
 162         file->private_data = (void *) wdev;
 163
 164         omap_wdt_set_timeout(wdev);
 165         omap_wdt_enable(wdev);
 166         return nonseekable_open(inode, file);
 167 }
 168
 169 static int omap_wdt_release(struct inode *inode, struct file *file)
 170 {
 171         struct omap_wdt_dev *wdev;
 172         wdev = file->private_data;
 173         /*
 174          *      Shut off the timer unless NOWAYOUT is defined.
 175          */
 176 #ifndef CONFIG_WATCHDOG_NOWAYOUT
 177
 178         omap_wdt_disable(wdev);
 179
 180         if (cpu_is_omap16xx())
 181                 clk_disable(wdev->armwdt_ck);   /* Disable the clock */
 182
 183         if (cpu_is_omap24xx() || cpu_is_omap34xx()) {
 184                 clk_disable(wdev->mpu_wdt_ick); /* Disable the clock */
 185                 clk_disable(wdev->mpu_wdt_fck); /* Disable the clock */
 186         }
 187 #else
 188         printk(KERN_CRIT "omap_wdt: Unexpected close, not stopping!\n");
 189 #endif
 190         wdev->omap_wdt_users = 0;
 191         return 0;
 192 }
 193
 194 static ssize_t omap_wdt_write(struct file *file, const char __user *data,
 195                 size_t len, loff_t *ppos)
 196 {
 197         struct omap_wdt_dev *wdev;
 198         wdev = file->private_data;
 199         /* Refresh LOAD_TIME. */
 200         if (len) {
 201                 spin_lock(&wdt_lock);
 202                 omap_wdt_ping(wdev);
 203                 spin_unlock(&wdt_lock);
 204         }
 205         return len;
 206 }
 207
 208 static long omap_wdt_ioctl(struct file *file, unsigned int cmd,
 209                                                 unsigned long arg)
 210 {
 211         struct omap_wdt_dev *wdev;
 212         int new_margin;
 213         static const struct watchdog_info ident = {
 214                 .identity = "OMAP Watchdog",
 215                 .options = WDIOF_SETTIMEOUT,
 216                 .firmware_version = 0,
 217         };
 218         wdev = file->private_data;
 219
 220         switch (cmd) {
 221         case WDIOC_GETSUPPORT:
 222                 return copy_to_user((struct watchdog_info __user *)arg, &ident,
 223                                 sizeof(ident));
 224         case WDIOC_GETSTATUS:
 225                 return put_user(0, (int __user *)arg);
 226         case WDIOC_GETBOOTSTATUS:
 227                 if (cpu_is_omap16xx())
 228                         return put_user(__raw_readw(ARM_SYSST),
 229                                         (int __user *)arg);
 230                 if (cpu_is_omap24xx())
 231                         return put_user(omap_prcm_get_reset_sources(),
 232                                         (int __user *)arg);
 233         case WDIOC_KEEPALIVE:
 234                 spin_lock(&wdt_lock);
 235                 omap_wdt_ping(wdev);
 236                 spin_unlock(&wdt_lock);
 237                 return 0;
 238         case WDIOC_SETTIMEOUT:
 239                 if (get_user(new_margin, (int __user *)arg))
 240                         return -EFAULT;
 241                 omap_wdt_adjust_timeout(new_margin);
 242
 243                 spin_lock(&wdt_lock);
 244                 omap_wdt_disable(wdev);
 245                 omap_wdt_set_timeout(wdev);
 246                 omap_wdt_enable(wdev);
 247
 248                 omap_wdt_ping(wdev);
 249                 spin_unlock(&wdt_lock);
 250                 /* Fall */
 251         case WDIOC_GETTIMEOUT:
 252                 return put_user(timer_margin, (int __user *)arg);
 253         default:
 254                 return -ENOTTY;
 255         }
 256         return 0;
 257 }
 258
 259 static const struct file_operations omap_wdt_fops = {
 260         .owner = THIS_MODULE,
 261         .write = omap_wdt_write,
 262         .unlocked_ioctl = omap_wdt_ioctl,
 263         .open = omap_wdt_open,
 264         .release = omap_wdt_release,
 265 };
 266
 267
 268 static int __init omap_wdt_probe(struct platform_device *pdev)
 269 {
 270         struct resource *res, *mem;
 271         int ret;
 272         struct omap_wdt_dev *wdev;
 273
 274         /* reserve static register mappings */
 275         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 276         if (!res)
 277                 return -ENOENT;
 278
 279         if (omap_wdt_dev)
 280                 return -EBUSY;
 281
 282         mem = request_mem_region(res->start, res->end - res->start + 1,
 283                                  pdev->name);
 284         if (mem == NULL)
 285                 return -EBUSY;
 286
 287         wdev = kzalloc(sizeof(struct omap_wdt_dev), GFP_KERNEL);
 288         if (!wdev) {
 289                 ret = -ENOMEM;
 290                 goto fail;
 291         }
 292         wdev->omap_wdt_users = 0;
 293         wdev->mem = mem;
 294
 295         if (cpu_is_omap16xx()) {
 296                 wdev->armwdt_ck = clk_get(&pdev->dev, "armwdt_ck");
 297                 if (IS_ERR(wdev->armwdt_ck)) {
 298                         ret = PTR_ERR(wdev->armwdt_ck);
 299                         wdev->armwdt_ck = NULL;
 300                         goto fail;
 301                 }
 302         }
 303
 304         if (cpu_is_omap24xx()) {
 305                 wdev->mpu_wdt_ick = clk_get(&pdev->dev, "mpu_wdt_ick");
 306                 if (IS_ERR(wdev->mpu_wdt_ick)) {
 307                         ret = PTR_ERR(wdev->mpu_wdt_ick);
 308                         wdev->mpu_wdt_ick = NULL;
 309                         goto fail;
 310                 }
 311                 wdev->mpu_wdt_fck = clk_get(&pdev->dev, "mpu_wdt_fck");
 312                 if (IS_ERR(wdev->mpu_wdt_fck)) {
 313                         ret = PTR_ERR(wdev->mpu_wdt_fck);
 314                         wdev->mpu_wdt_fck = NULL;
 315                         goto fail;
 316                 }
 317         }
 318
 319         if (cpu_is_omap34xx()) {
 320                 wdev->mpu_wdt_ick = clk_get(&pdev->dev, "wdt2_ick");
 321                 if (IS_ERR(wdev->mpu_wdt_ick)) {
 322                         ret = PTR_ERR(wdev->mpu_wdt_ick);
 323                         wdev->mpu_wdt_ick = NULL;
 324                         goto fail;
 325                 }
 326                 wdev->mpu_wdt_fck = clk_get(&pdev->dev, "wdt2_fck");
 327                 if (IS_ERR(wdev->mpu_wdt_fck)) {
 328                         ret = PTR_ERR(wdev->mpu_wdt_fck);
 329                         wdev->mpu_wdt_fck = NULL;
 330                         goto fail;
 331                 }
 332         }
 333         wdev->base = ioremap(res->start, res->end - res->start + 1);
 334         if (!wdev->base) {
 335                 ret = -ENOMEM;
 336                 goto fail;
 337         }
 338
 339         platform_set_drvdata(pdev, wdev);
 340
 341         omap_wdt_disable(wdev);
 342         omap_wdt_adjust_timeout(timer_margin);
 343
 344         wdev->omap_wdt_miscdev.parent = &pdev->dev;
 345         wdev->omap_wdt_miscdev.minor = WATCHDOG_MINOR;
 346         wdev->omap_wdt_miscdev.name = "watchdog";
 347         wdev->omap_wdt_miscdev.fops = &omap_wdt_fops;
 348
 349         ret = misc_register(&(wdev->omap_wdt_miscdev));
 350         if (ret)
 351                 goto fail;
 352
 353         pr_info("OMAP Watchdog Timer Rev 0x%02x: initial timeout %d sec\n",
 354                 __raw_readl(wdev->base + OMAP_WATCHDOG_REV) & 0xFF,
 355                 timer_margin);
 356
 357         /* autogate OCP interface clock */
 358         __raw_writel(0x01, wdev->base + OMAP_WATCHDOG_SYS_CONFIG);
 359
 360         omap_wdt_dev = pdev;
 361
 362         return 0;
 363
 364 fail:
 365         if (wdev) {
 366                 platform_set_drvdata(pdev, NULL);
 367                 if (wdev->armwdt_ck)
 368                         clk_put(wdev->armwdt_ck);
 369                 if (wdev->mpu_wdt_ick)
 370                         clk_put(wdev->mpu_wdt_ick);
 371                 if (wdev->mpu_wdt_fck)
 372                         clk_put(wdev->mpu_wdt_fck);
 373                 iounmap(wdev->base);
 374                 kfree(wdev);
 375         }
 376         if (mem) {
 377                 release_mem_region(res->start, res->end - res->start + 1);
 378         }
 379         return ret;
 380 }
 381
 382 static void omap_wdt_shutdown(struct platform_device *pdev)
 383 {
 384         struct omap_wdt_dev *wdev;
 385         wdev = platform_get_drvdata(pdev);
 386
 387         if (wdev->omap_wdt_users)
 388                 omap_wdt_disable(wdev);
 389 }
 390
 391 static int omap_wdt_remove(struct platform_device *pdev)
 392 {
 393         struct omap_wdt_dev *wdev;
 394         wdev = platform_get_drvdata(pdev);
 395         struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 396
 397         if (!res)
 398                 return -ENOENT;
 399
 400         misc_deregister(&(wdev->omap_wdt_miscdev));
 401         release_mem_region(res->start, res->end - res->start + 1);
 402         platform_set_drvdata(pdev, NULL);
 403         if (wdev->armwdt_ck) {
 404                 clk_put(wdev->armwdt_ck);
 405                 wdev->armwdt_ck = NULL;
 406         }
 407         if (wdev->mpu_wdt_ick) {
 408                 clk_put(wdev->mpu_wdt_ick);
 409                 wdev->mpu_wdt_ick = NULL;
 410         }
 411         if (wdev->mpu_wdt_fck) {
 412                 clk_put(wdev->mpu_wdt_fck);
 413                 wdev->mpu_wdt_fck = NULL;
 414         }
 415         iounmap(wdev->base);
 416
 417         kfree(wdev);
 418         omap_wdt_dev = NULL;
 419         return 0;
 420 }
 421
 422 #ifdef  CONFIG_PM
 423
 424 /* REVISIT ... not clear this is the best way to handle system suspend; and
 425  * it's very inappropriate for selective device suspend (e.g. suspending this
 426  * through sysfs rather than by stopping the watchdog daemon).  Also, this
 427  * may not play well enough with NOWAYOUT...
 428  */
 429
 430 static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 431 {
 432         struct omap_wdt_dev *wdev;
 433         wdev = platform_get_drvdata(pdev);
 434         if (wdev->omap_wdt_users)
 435                 omap_wdt_disable(wdev);
 436         return 0;
 437 }
 438
 439 static int omap_wdt_resume(struct platform_device *pdev)
 440 {
 441         struct omap_wdt_dev *wdev;
 442         wdev = platform_get_drvdata(pdev);
 443         if (wdev->omap_wdt_users) {
 444                 omap_wdt_enable(wdev);
 445                 omap_wdt_ping(wdev);
 446         }
 447         return 0;
 448 }
 449
 450 #else
 451 #define omap_wdt_suspend        NULL
 452 #define omap_wdt_resume         NULL
 453 #endif
 454
 455 static struct platform_driver omap_wdt_driver = {
 456         .probe          = omap_wdt_probe,
 457         .remove         = omap_wdt_remove,
 458         .shutdown       = omap_wdt_shutdown,
 459         .suspend        = omap_wdt_suspend,
 460         .resume         = omap_wdt_resume,
 461         .driver         = {
 462                 .owner  = THIS_MODULE,
 463                 .name   = "omap_wdt",
 464         },
 465 };
 466
 467 static int __init omap_wdt_init(void)
 468 {
 469         spin_lock_init(&wdt_lock);
 470         return platform_driver_register(&omap_wdt_driver);
 471 }
 472
 473 static void __exit omap_wdt_exit(void)
 474 {
 475         platform_driver_unregister(&omap_wdt_driver);
 476 }
 477
 478 module_init(omap_wdt_init);
 479 module_exit(omap_wdt_exit);
 480
 481 MODULE_AUTHOR("George G. Davis");
 482 MODULE_LICENSE("GPL");
 483 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 484 MODULE_ALIAS("platform:omap_wdt");