drivers/watchdog/omap_wdt.c

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