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 <asm/io.h>
  44 #include <asm/uaccess.h>
  45 #include <asm/hardware.h>
  46 #include <asm/bitops.h>
  47
  48 #include <asm/arch/prcm.h>
  49
  50 #include "omap_wdt.h"
  51
  52 static struct platform_device *omap_wdt_dev;
  53
  54 static unsigned timer_margin;
  55 module_param(timer_margin, uint, 0);
  56 MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)");
  57
  58 static unsigned int wdt_trgr_pattern = 0x1234;
  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
 194 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                 omap_wdt_ping(wdev);
 202         return len;
 203 }
 204
 205 static int
 206 omap_wdt_ioctl(struct inode *inode, struct file *file,
 207         unsigned int cmd, unsigned long arg)
 208 {
 209         struct omap_wdt_dev *wdev;
 210         int new_margin;
 211         static struct watchdog_info ident = {
 212                 .identity = "OMAP Watchdog",
 213                 .options = WDIOF_SETTIMEOUT,
 214                 .firmware_version = 0,
 215         };
 216         wdev = file->private_data;
 217
 218         switch (cmd) {
 219         default:
 220                 return -ENOTTY;
 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(omap_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                 omap_wdt_ping(wdev);
 235                 return 0;
 236         case WDIOC_SETTIMEOUT:
 237                 if (get_user(new_margin, (int __user *)arg))
 238                         return -EFAULT;
 239                 omap_wdt_adjust_timeout(new_margin);
 240
 241                 omap_wdt_disable(wdev);
 242                 omap_wdt_set_timeout(wdev);
 243                 omap_wdt_enable(wdev);
 244
 245                 omap_wdt_ping(wdev);
 246                 /* Fall */
 247         case WDIOC_GETTIMEOUT:
 248                 return put_user(timer_margin, (int __user *)arg);
 249         }
 250         return 0;
 251 }
 252
 253 static const struct file_operations omap_wdt_fops = {
 254         .owner = THIS_MODULE,
 255         .write = omap_wdt_write,
 256         .ioctl = omap_wdt_ioctl,
 257         .open = omap_wdt_open,
 258         .release = omap_wdt_release,
 259 };
 260
 261
 262 static int __init omap_wdt_probe(struct platform_device *pdev)
 263 {
 264         struct resource *res, *mem;
 265         int ret;
 266         struct omap_wdt_dev *wdev;
 267
 268         /* reserve static register mappings */
 269         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 270         if (!res)
 271                 return -ENOENT;
 272
 273         if (omap_wdt_dev)
 274                 return -EBUSY;
 275
 276         mem = request_mem_region(res->start, res->end - res->start + 1,
 277                                  pdev->name);
 278         if (mem == NULL)
 279                 return -EBUSY;
 280
 281         wdev = kzalloc(sizeof(struct omap_wdt_dev), GFP_KERNEL);
 282         if (!wdev) {
 283                 ret = -ENOMEM;
 284                 goto fail;
 285         }
 286         wdev->omap_wdt_users = 0;
 287         wdev->mem = mem;
 288
 289         if (cpu_is_omap16xx()) {
 290                 wdev->armwdt_ck = clk_get(&pdev->dev, "armwdt_ck");
 291                 if (IS_ERR(wdev->armwdt_ck)) {
 292                         ret = PTR_ERR(wdev->armwdt_ck);
 293                         wdev->armwdt_ck = NULL;
 294                         goto fail;
 295                 }
 296         }
 297
 298         if (cpu_is_omap24xx()) {
 299                 wdev->mpu_wdt_ick = clk_get(&pdev->dev, "mpu_wdt_ick");
 300                 if (IS_ERR(wdev->mpu_wdt_ick)) {
 301                         ret = PTR_ERR(wdev->mpu_wdt_ick);
 302                         wdev->mpu_wdt_ick = NULL;
 303                         goto fail;
 304                 }
 305                 wdev->mpu_wdt_fck = clk_get(&pdev->dev, "mpu_wdt_fck");
 306                 if (IS_ERR(wdev->mpu_wdt_fck)) {
 307                         ret = PTR_ERR(wdev->mpu_wdt_fck);
 308                         wdev->mpu_wdt_fck = NULL;
 309                         goto fail;
 310                 }
 311         }
 312
 313         if (cpu_is_omap34xx()) {
 314                 wdev->mpu_wdt_ick = clk_get(&pdev->dev, "wdt2_ick");
 315                 if (IS_ERR(wdev->mpu_wdt_ick)) {
 316                         ret = PTR_ERR(wdev->mpu_wdt_ick);
 317                         wdev->mpu_wdt_ick = NULL;
 318                         goto fail;
 319                 }
 320                 wdev->mpu_wdt_fck = clk_get(&pdev->dev, "wdt2_fck");
 321                 if (IS_ERR(wdev->mpu_wdt_fck)) {
 322                         ret = PTR_ERR(wdev->mpu_wdt_fck);
 323                         wdev->mpu_wdt_fck = NULL;
 324                         goto fail;
 325                 }
 326         }
 327         wdev->base = (void __iomem *) (mem->start);
 328         platform_set_drvdata(pdev, wdev);
 329
 330         omap_wdt_disable(wdev);
 331         omap_wdt_adjust_timeout(timer_margin);
 332
 333         wdev->omap_wdt_miscdev.parent = &pdev->dev;
 334         wdev->omap_wdt_miscdev.minor = WATCHDOG_MINOR;
 335         wdev->omap_wdt_miscdev.name = "watchdog";
 336         wdev->omap_wdt_miscdev.fops = &omap_wdt_fops;
 337
 338         ret = misc_register(&(wdev->omap_wdt_miscdev));
 339         if (ret)
 340                 goto fail;
 341
 342         pr_info("OMAP Watchdog Timer Rev 0x%02x: initial timeout %d sec\n",
 343                 omap_readl(wdev->base + OMAP_WATCHDOG_REV) & 0xFF,
 344                 timer_margin);
 345
 346         /* autogate OCP interface clock */
 347         omap_writel(0x01, wdev->base + OMAP_WATCHDOG_SYS_CONFIG);
 348
 349         omap_wdt_dev = pdev;
 350
 351         return 0;
 352
 353 fail:
 354         if (wdev) {
 355                 platform_set_drvdata(pdev, NULL);
 356                 if (wdev->armwdt_ck)
 357                         clk_put(wdev->armwdt_ck);
 358                 if (wdev->mpu_wdt_ick)
 359                         clk_put(wdev->mpu_wdt_ick);
 360                 if (wdev->mpu_wdt_fck)
 361                         clk_put(wdev->mpu_wdt_fck);
 362                 kfree(wdev);
 363         }
 364         if (mem) {
 365                 release_resource(mem);
 366         }
 367         return ret;
 368 }
 369
 370 static void omap_wdt_shutdown(struct platform_device *pdev)
 371 {
 372         struct omap_wdt_dev *wdev;
 373         wdev = platform_get_drvdata(pdev);
 374
 375         if (wdev->omap_wdt_users)
 376                 omap_wdt_disable(wdev);
 377 }
 378
 379 static int omap_wdt_remove(struct platform_device *pdev)
 380 {
 381         struct omap_wdt_dev *wdev;
 382         wdev = platform_get_drvdata(pdev);
 383
 384         misc_deregister(&(wdev->omap_wdt_miscdev));
 385         release_resource(wdev->mem);
 386         platform_set_drvdata(pdev, NULL);
 387         if (wdev->armwdt_ck) {
 388                 clk_put(wdev->armwdt_ck);
 389                 wdev->armwdt_ck = NULL;
 390         }
 391         if (wdev->mpu_wdt_ick) {
 392                 clk_put(wdev->mpu_wdt_ick);
 393                 wdev->mpu_wdt_ick = NULL;
 394         }
 395         if (wdev->mpu_wdt_fck) {
 396                 clk_put(wdev->mpu_wdt_fck);
 397                 wdev->mpu_wdt_fck = NULL;
 398         }
 399         kfree(wdev);
 400         omap_wdt_dev = NULL;
 401         return 0;
 402 }
 403
 404 #ifdef  CONFIG_PM
 405
 406 /* REVISIT ... not clear this is the best way to handle system suspend; and
 407  * it's very inappropriate for selective device suspend (e.g. suspending this
 408  * through sysfs rather than by stopping the watchdog daemon).  Also, this
 409  * may not play well enough with NOWAYOUT...
 410  */
 411
 412 static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 413 {
 414         struct omap_wdt_dev *wdev;
 415         wdev = platform_get_drvdata(pdev);
 416         if (wdev->omap_wdt_users)
 417                 omap_wdt_disable(wdev);
 418         return 0;
 419 }
 420
 421 static int omap_wdt_resume(struct platform_device *pdev)
 422 {
 423         struct omap_wdt_dev *wdev;
 424         wdev = platform_get_drvdata(pdev);
 425         if (wdev->omap_wdt_users) {
 426                 omap_wdt_enable(wdev);
 427                 omap_wdt_ping(wdev);
 428         }
 429         return 0;
 430 }
 431
 432 #else
 433 #define omap_wdt_suspend        NULL
 434 #define omap_wdt_resume         NULL
 435 #endif
 436
 437 static struct platform_driver omap_wdt_driver = {
 438         .probe          = omap_wdt_probe,
 439         .remove         = omap_wdt_remove,
 440         .shutdown       = omap_wdt_shutdown,
 441         .suspend        = omap_wdt_suspend,
 442         .resume         = omap_wdt_resume,
 443         .driver         = {
 444                 .owner  = THIS_MODULE,
 445                 .name   = "omap_wdt",
 446         },
 447 };
 448
 449 static int __init omap_wdt_init(void)
 450 {
 451         return platform_driver_register(&omap_wdt_driver);
 452 }
 453
 454 static void __exit omap_wdt_exit(void)
 455 {
 456         platform_driver_unregister(&omap_wdt_driver);
 457 }
 458
 459 module_init(omap_wdt_init);
 460 module_exit(omap_wdt_exit);
 461
 462 MODULE_AUTHOR("George G. Davis");
 463 MODULE_LICENSE("GPL");
 464 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 465 MODULE_ALIAS("platform:omap_wdt");