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   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
  74         /* wait for posted write to complete */
  75         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x08)
  76                 cpu_relax();
  77
  78         wdt_trgr_pattern = ~wdt_trgr_pattern;
  79         __raw_writel(wdt_trgr_pattern, (base + OMAP_WATCHDOG_TGR));
  80
  81         /* wait for posted write to complete */
  82         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x08)
  83                 cpu_relax();
  84         /* reloaded WCRR from WLDR */
  85 }
  86
  87 static void omap_wdt_enable(struct omap_wdt_dev *wdev)
  88 {
  89         void __iomem *base = wdev->base;
  90
  91         /* Sequence to enable the watchdog */
  92         __raw_writel(0xBBBB, base + OMAP_WATCHDOG_SPR);
  93         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x10)
  94                 cpu_relax();
  95
  96         __raw_writel(0x4444, base + OMAP_WATCHDOG_SPR);
  97         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x10)
  98                 cpu_relax();
  99 }
 100
 101 static void omap_wdt_disable(struct omap_wdt_dev *wdev)
 102 {
 103         void __iomem *base = wdev->base;
 104
 105         /* sequence required to disable watchdog */
 106         __raw_writel(0xAAAA, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */
 107         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x10)
 108                 cpu_relax();
 109
 110         __raw_writel(0x5555, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */
 111         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x10)
 112                 cpu_relax();
 113 }
 114
 115 static void omap_wdt_adjust_timeout(unsigned new_timeout)
 116 {
 117         if (new_timeout < TIMER_MARGIN_MIN)
 118                 new_timeout = TIMER_MARGIN_DEFAULT;
 119         if (new_timeout > TIMER_MARGIN_MAX)
 120                 new_timeout = TIMER_MARGIN_MAX;
 121         timer_margin = new_timeout;
 122 }
 123
 124 static void omap_wdt_set_timeout(struct omap_wdt_dev *wdev)
 125 {
 126         u32 pre_margin = GET_WLDR_VAL(timer_margin);
 127         void __iomem *base = wdev->base;
 128
 129         /* just count up at 32 KHz */
 130         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x04)
 131                 cpu_relax();
 132
 133         __raw_writel(pre_margin, base + OMAP_WATCHDOG_LDR);
 134         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x04)
 135                 cpu_relax();
 136 }
 137
 138 /*
 139  *      Allow only one task to hold it open
 140  */
 141 static int omap_wdt_open(struct inode *inode, struct file *file)
 142 {
 143         struct omap_wdt_dev *wdev = platform_get_drvdata(omap_wdt_dev);
 144         void __iomem *base = wdev->base;
 145
 146         if (test_and_set_bit(1, (unsigned long *)&(wdev->omap_wdt_users)))
 147                 return -EBUSY;
 148
 149         if (cpu_is_omap16xx())
 150                 clk_enable(wdev->armwdt_ck);    /* Enable the clock */
 151
 152         if (cpu_is_omap24xx() || cpu_is_omap34xx()) {
 153                 clk_enable(wdev->mpu_wdt_ick);    /* Enable the interface clock */
 154                 clk_enable(wdev->mpu_wdt_fck);    /* Enable the functional clock */
 155         }
 156
 157         /* initialize prescaler */
 158         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x01)
 159                 cpu_relax();
 160
 161         __raw_writel((1 << 5) | (PTV << 2), base + OMAP_WATCHDOG_CNTRL);
 162         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x01)
 163                 cpu_relax();
 164
 165         file->private_data = (void *) wdev;
 166
 167         omap_wdt_set_timeout(wdev);
 168         omap_wdt_enable(wdev);
 169
 170         return nonseekable_open(inode, file);
 171 }
 172
 173 static int omap_wdt_release(struct inode *inode, struct file *file)
 174 {
 175         struct omap_wdt_dev *wdev = file->private_data;
 176
 177         /*
 178          *      Shut off the timer unless NOWAYOUT is defined.
 179          */
 180 #ifndef CONFIG_WATCHDOG_NOWAYOUT
 181
 182         omap_wdt_disable(wdev);
 183
 184         if (cpu_is_omap16xx())
 185                 clk_disable(wdev->armwdt_ck);   /* Disable the clock */
 186
 187         if (cpu_is_omap24xx() || cpu_is_omap34xx()) {
 188                 clk_disable(wdev->mpu_wdt_ick); /* Disable the clock */
 189                 clk_disable(wdev->mpu_wdt_fck); /* Disable the clock */
 190         }
 191 #else
 192         printk(KERN_CRIT "omap_wdt: Unexpected close, not stopping!\n");
 193 #endif
 194         wdev->omap_wdt_users = 0;
 195
 196         return 0;
 197 }
 198
 199 static ssize_t omap_wdt_write(struct file *file, const char __user *data,
 200                 size_t len, loff_t *ppos)
 201 {
 202         struct omap_wdt_dev *wdev = file->private_data;
 203
 204         /* Refresh LOAD_TIME. */
 205         if (len) {
 206                 spin_lock(&wdt_lock);
 207                 omap_wdt_ping(wdev);
 208                 spin_unlock(&wdt_lock);
 209         }
 210         return len;
 211 }
 212
 213 static long omap_wdt_ioctl(struct file *file, unsigned int cmd,
 214                                                 unsigned long arg)
 215 {
 216         struct omap_wdt_dev *wdev;
 217         int new_margin;
 218         static const struct watchdog_info ident = {
 219                 .identity = "OMAP Watchdog",
 220                 .options = WDIOF_SETTIMEOUT,
 221                 .firmware_version = 0,
 222         };
 223
 224         wdev = file->private_data;
 225
 226         switch (cmd) {
 227         case WDIOC_GETSUPPORT:
 228                 return copy_to_user((struct watchdog_info __user *)arg, &ident,
 229                                 sizeof(ident));
 230         case WDIOC_GETSTATUS:
 231                 return put_user(0, (int __user *)arg);
 232         case WDIOC_GETBOOTSTATUS:
 233                 if (cpu_is_omap16xx())
 234                         return put_user(__raw_readw(ARM_SYSST),
 235                                         (int __user *)arg);
 236                 if (cpu_is_omap24xx())
 237                         return put_user(omap_prcm_get_reset_sources(),
 238                                         (int __user *)arg);
 239         case WDIOC_KEEPALIVE:
 240                 spin_lock(&wdt_lock);
 241                 omap_wdt_ping(wdev);
 242                 spin_unlock(&wdt_lock);
 243                 return 0;
 244         case WDIOC_SETTIMEOUT:
 245                 if (get_user(new_margin, (int __user *)arg))
 246                         return -EFAULT;
 247                 omap_wdt_adjust_timeout(new_margin);
 248
 249                 spin_lock(&wdt_lock);
 250                 omap_wdt_disable(wdev);
 251                 omap_wdt_set_timeout(wdev);
 252                 omap_wdt_enable(wdev);
 253
 254                 omap_wdt_ping(wdev);
 255                 spin_unlock(&wdt_lock);
 256                 /* Fall */
 257         case WDIOC_GETTIMEOUT:
 258                 return put_user(timer_margin, (int __user *)arg);
 259         default:
 260                 return -ENOTTY;
 261         }
 262 }
 263
 264 static const struct file_operations omap_wdt_fops = {
 265         .owner = THIS_MODULE,
 266         .write = omap_wdt_write,
 267         .unlocked_ioctl = omap_wdt_ioctl,
 268         .open = omap_wdt_open,
 269         .release = omap_wdt_release,
 270 };
 271
 272 static int __init omap_wdt_probe(struct platform_device *pdev)
 273 {
 274         struct resource *res, *mem;
 275         struct omap_wdt_dev *wdev;
 276         int ret;
 277
 278         /* reserve static register mappings */
 279         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 280         if (!res) {
 281                 ret = -ENOENT;
 282                 goto err_get_resource;
 283         }
 284
 285         if (omap_wdt_dev) {
 286                 ret = -EBUSY;
 287                 goto err_busy;
 288         }
 289
 290         mem = request_mem_region(res->start, res->end - res->start + 1,
 291                                  pdev->name);
 292         if (!mem) {
 293                 ret = -EBUSY;
 294                 goto err_busy;
 295         }
 296
 297         wdev = kzalloc(sizeof(struct omap_wdt_dev), GFP_KERNEL);
 298         if (!wdev) {
 299                 ret = -ENOMEM;
 300                 goto err_kzalloc;
 301         }
 302
 303         wdev->omap_wdt_users = 0;
 304         wdev->mem = mem;
 305
 306         if (cpu_is_omap16xx()) {
 307                 wdev->armwdt_ck = clk_get(&pdev->dev, "armwdt_ck");
 308                 if (IS_ERR(wdev->armwdt_ck)) {
 309                         ret = PTR_ERR(wdev->armwdt_ck);
 310                         wdev->armwdt_ck = NULL;
 311                         goto err_clk;
 312                 }
 313         }
 314
 315         if (cpu_is_omap24xx()) {
 316                 wdev->mpu_wdt_ick = clk_get(&pdev->dev, "mpu_wdt_ick");
 317                 if (IS_ERR(wdev->mpu_wdt_ick)) {
 318                         ret = PTR_ERR(wdev->mpu_wdt_ick);
 319                         wdev->mpu_wdt_ick = NULL;
 320                         goto err_clk;
 321                 }
 322                 wdev->mpu_wdt_fck = clk_get(&pdev->dev, "mpu_wdt_fck");
 323                 if (IS_ERR(wdev->mpu_wdt_fck)) {
 324                         ret = PTR_ERR(wdev->mpu_wdt_fck);
 325                         wdev->mpu_wdt_fck = NULL;
 326                         goto err_clk;
 327                 }
 328         }
 329
 330         if (cpu_is_omap34xx()) {
 331                 wdev->mpu_wdt_ick = clk_get(&pdev->dev, "wdt2_ick");
 332                 if (IS_ERR(wdev->mpu_wdt_ick)) {
 333                         ret = PTR_ERR(wdev->mpu_wdt_ick);
 334                         wdev->mpu_wdt_ick = NULL;
 335                         goto err_clk;
 336                 }
 337                 wdev->mpu_wdt_fck = clk_get(&pdev->dev, "wdt2_fck");
 338                 if (IS_ERR(wdev->mpu_wdt_fck)) {
 339                         ret = PTR_ERR(wdev->mpu_wdt_fck);
 340                         wdev->mpu_wdt_fck = NULL;
 341                         goto err_clk;
 342                 }
 343         }
 344         wdev->base = ioremap(res->start, res->end - res->start + 1);
 345         if (!wdev->base) {
 346                 ret = -ENOMEM;
 347                 goto err_ioremap;
 348         }
 349
 350         platform_set_drvdata(pdev, wdev);
 351
 352         omap_wdt_disable(wdev);
 353         omap_wdt_adjust_timeout(timer_margin);
 354
 355         wdev->omap_wdt_miscdev.parent = &pdev->dev;
 356         wdev->omap_wdt_miscdev.minor = WATCHDOG_MINOR;
 357         wdev->omap_wdt_miscdev.name = "watchdog";
 358         wdev->omap_wdt_miscdev.fops = &omap_wdt_fops;
 359
 360         ret = misc_register(&(wdev->omap_wdt_miscdev));
 361         if (ret)
 362                 goto err_misc;
 363
 364         pr_info("OMAP Watchdog Timer Rev 0x%02x: initial timeout %d sec\n",
 365                 __raw_readl(wdev->base + OMAP_WATCHDOG_REV) & 0xFF,
 366                 timer_margin);
 367
 368         /* autogate OCP interface clock */
 369         __raw_writel(0x01, wdev->base + OMAP_WATCHDOG_SYS_CONFIG);
 370
 371         omap_wdt_dev = pdev;
 372
 373         return 0;
 374
 375 err_misc:
 376         platform_set_drvdata(pdev, NULL);
 377         iounmap(wdev->base);
 378
 379 err_ioremap:
 380         wdev->base = NULL;
 381
 382 err_clk:
 383         if (wdev->armwdt_ck)
 384                 clk_put(wdev->armwdt_ck);
 385         if (wdev->mpu_wdt_ick)
 386                 clk_put(wdev->mpu_wdt_ick);
 387         if (wdev->mpu_wdt_fck)
 388                 clk_put(wdev->mpu_wdt_fck);
 389         kfree(wdev);
 390
 391 err_kzalloc:
 392         release_mem_region(res->start, res->end - res->start + 1);
 393
 394 err_busy:
 395 err_get_resource:
 396
 397         return ret;
 398 }
 399
 400 static void omap_wdt_shutdown(struct platform_device *pdev)
 401 {
 402         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 403
 404         if (wdev->omap_wdt_users)
 405                 omap_wdt_disable(wdev);
 406 }
 407
 408 static int omap_wdt_remove(struct platform_device *pdev)
 409 {
 410         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 411         struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 412
 413         if (!res)
 414                 return -ENOENT;
 415
 416         misc_deregister(&(wdev->omap_wdt_miscdev));
 417         release_mem_region(res->start, res->end - res->start + 1);
 418         platform_set_drvdata(pdev, NULL);
 419
 420         if (wdev->armwdt_ck) {
 421                 clk_put(wdev->armwdt_ck);
 422                 wdev->armwdt_ck = NULL;
 423         }
 424
 425         if (wdev->mpu_wdt_ick) {
 426                 clk_put(wdev->mpu_wdt_ick);
 427                 wdev->mpu_wdt_ick = NULL;
 428         }
 429
 430         if (wdev->mpu_wdt_fck) {
 431                 clk_put(wdev->mpu_wdt_fck);
 432                 wdev->mpu_wdt_fck = NULL;
 433         }
 434         iounmap(wdev->base);
 435
 436         kfree(wdev);
 437         omap_wdt_dev = NULL;
 438
 439         return 0;
 440 }
 441
 442 #ifdef  CONFIG_PM
 443
 444 /* REVISIT ... not clear this is the best way to handle system suspend; and
 445  * it's very inappropriate for selective device suspend (e.g. suspending this
 446  * through sysfs rather than by stopping the watchdog daemon).  Also, this
 447  * may not play well enough with NOWAYOUT...
 448  */
 449
 450 static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 451 {
 452         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 453
 454         if (wdev->omap_wdt_users)
 455                 omap_wdt_disable(wdev);
 456
 457         return 0;
 458 }
 459
 460 static int omap_wdt_resume(struct platform_device *pdev)
 461 {
 462         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 463
 464         if (wdev->omap_wdt_users) {
 465                 omap_wdt_enable(wdev);
 466                 omap_wdt_ping(wdev);
 467         }
 468
 469         return 0;
 470 }
 471
 472 #else
 473 #define omap_wdt_suspend        NULL
 474 #define omap_wdt_resume         NULL
 475 #endif
 476
 477 static struct platform_driver omap_wdt_driver = {
 478         .probe          = omap_wdt_probe,
 479         .remove         = omap_wdt_remove,
 480         .shutdown       = omap_wdt_shutdown,
 481         .suspend        = omap_wdt_suspend,
 482         .resume         = omap_wdt_resume,
 483         .driver         = {
 484                 .owner  = THIS_MODULE,
 485                 .name   = "omap_wdt",
 486         },
 487 };
 488
 489 static int __init omap_wdt_init(void)
 490 {
 491         spin_lock_init(&wdt_lock);
 492         return platform_driver_register(&omap_wdt_driver);
 493 }
 494
 495 static void __exit omap_wdt_exit(void)
 496 {
 497         platform_driver_unregister(&omap_wdt_driver);
 498 }
 499
 500 module_init(omap_wdt_init);
 501 module_exit(omap_wdt_exit);
 502
 503 MODULE_AUTHOR("George G. Davis");
 504 MODULE_LICENSE("GPL");
 505 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 506 MODULE_ALIAS("platform:omap_wdt");