drivers/char/watchdog/omap_wdt.c

   1 /*
   2  * linux/drivers/char/watchdog/omap_wdt.c
   3  *
   4  * Watchdog driver for the TI OMAP 16xx & 24xx 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()) {
 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                 clk_put(wdev->armwdt_ck);
 182                 wdev->armwdt_ck = NULL;
 183         }
 184
 185         if (cpu_is_omap24xx()) {
 186                 clk_disable(wdev->mpu_wdt_ick); /* Disable the clock */
 187                 clk_disable(wdev->mpu_wdt_fck); /* Disable the clock */
 188                 clk_put(wdev->mpu_wdt_ick);
 189                 clk_put(wdev->mpu_wdt_fck);
 190                 wdev->mpu_wdt_ick = NULL;
 191                 wdev->mpu_wdt_fck = NULL;
 192         }
 193 #else
 194         printk(KERN_CRIT "omap_wdt: Unexpected close, not stopping!\n");
 195 #endif
 196         wdev->omap_wdt_users = 0;
 197         return 0;
 198 }
 199
 200 static ssize_t
 201 omap_wdt_write(struct file *file, const char __user *data,
 202                 size_t len, loff_t *ppos)
 203 {
 204         struct omap_wdt_dev *wdev;
 205         wdev = file->private_data;
 206         /* Refresh LOAD_TIME. */
 207         if (len)
 208                 omap_wdt_ping(wdev);
 209         return len;
 210 }
 211
 212 static int
 213 omap_wdt_ioctl(struct inode *inode, struct file *file,
 214         unsigned int cmd, unsigned long arg)
 215 {
 216         struct omap_wdt_dev *wdev;
 217         int new_margin;
 218         static struct watchdog_info ident = {
 219                 .identity = "OMAP Watchdog",
 220                 .options = WDIOF_SETTIMEOUT,
 221                 .firmware_version = 0,
 222         };
 223         wdev = file->private_data;
 224
 225         switch (cmd) {
 226         default:
 227                 return -ENOTTY;
 228         case WDIOC_GETSUPPORT:
 229                 return copy_to_user((struct watchdog_info __user *)arg, &ident,
 230                                 sizeof(ident));
 231         case WDIOC_GETSTATUS:
 232                 return put_user(0, (int __user *)arg);
 233         case WDIOC_GETBOOTSTATUS:
 234                 if (cpu_is_omap16xx())
 235                         return put_user(omap_readw(ARM_SYSST),
 236                                         (int __user *)arg);
 237                 if (cpu_is_omap24xx())
 238                         return put_user(omap_prcm_get_reset_sources(),
 239                                         (int __user *)arg);
 240         case WDIOC_KEEPALIVE:
 241                 omap_wdt_ping(wdev);
 242                 return 0;
 243         case WDIOC_SETTIMEOUT:
 244                 if (get_user(new_margin, (int __user *)arg))
 245                         return -EFAULT;
 246                 omap_wdt_adjust_timeout(new_margin);
 247
 248                 omap_wdt_disable(wdev);
 249                 omap_wdt_set_timeout(wdev);
 250                 omap_wdt_enable(wdev);
 251
 252                 omap_wdt_ping(wdev);
 253                 /* Fall */
 254         case WDIOC_GETTIMEOUT:
 255                 return put_user(timer_margin, (int __user *)arg);
 256         }
 257         return 0;
 258 }
 259
 260 static const struct file_operations omap_wdt_fops = {
 261         .owner = THIS_MODULE,
 262         .write = omap_wdt_write,
 263         .ioctl = omap_wdt_ioctl,
 264         .open = omap_wdt_open,
 265         .release = omap_wdt_release,
 266 };
 267
 268
 269 static int __init omap_wdt_probe(struct platform_device *pdev)
 270 {
 271         struct resource *res, *mem;
 272         int ret;
 273         struct omap_wdt_dev *wdev;
 274
 275         /* reserve static register mappings */
 276         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 277         if (!res)
 278                 return -ENOENT;
 279
 280         if (omap_wdt_dev)
 281                 return -EBUSY;
 282
 283         mem = request_mem_region(res->start, res->end - res->start + 1,
 284                                  pdev->name);
 285         if (mem == NULL)
 286                 return -EBUSY;
 287
 288         wdev = kzalloc(sizeof(struct omap_wdt_dev), GFP_KERNEL);
 289         if (!wdev) {
 290                 ret = -ENOMEM;
 291                 goto fail;
 292         }
 293         wdev->omap_wdt_users = 0;
 294         wdev->mem = mem;
 295
 296         if (cpu_is_omap16xx()) {
 297                 wdev->armwdt_ck = clk_get(&pdev->dev, "armwdt_ck");
 298                 if (IS_ERR(wdev->armwdt_ck)) {
 299                         ret = PTR_ERR(wdev->armwdt_ck);
 300                         wdev->armwdt_ck = NULL;
 301                         goto fail;
 302                 }
 303         }
 304
 305         if (cpu_is_omap24xx()) {
 306                 wdev->mpu_wdt_ick = clk_get(&pdev->dev, "mpu_wdt_ick");
 307                 if (IS_ERR(wdev->mpu_wdt_ick)) {
 308                         ret = PTR_ERR(wdev->mpu_wdt_ick);
 309                         wdev->mpu_wdt_ick = NULL;
 310                         goto fail;
 311                 }
 312                 wdev->mpu_wdt_fck = clk_get(&pdev->dev, "mpu_wdt_fck");
 313                 if (IS_ERR(wdev->mpu_wdt_fck)) {
 314                         ret = PTR_ERR(wdev->mpu_wdt_fck);
 315                         wdev->mpu_wdt_fck = NULL;
 316                         goto fail;
 317                 }
 318         }
 319         wdev->base = (void __iomem *) (mem->start);
 320         platform_set_drvdata(pdev, wdev);
 321
 322         omap_wdt_disable(wdev);
 323         omap_wdt_adjust_timeout(timer_margin);
 324
 325         wdev->omap_wdt_miscdev.parent = &pdev->dev;
 326         wdev->omap_wdt_miscdev.minor = WATCHDOG_MINOR;
 327         wdev->omap_wdt_miscdev.name = "watchdog";
 328         wdev->omap_wdt_miscdev.fops = &omap_wdt_fops;
 329
 330         ret = misc_register(&(wdev->omap_wdt_miscdev));
 331         if (ret)
 332                 goto fail;
 333
 334         pr_info("OMAP Watchdog Timer Rev 0x%02x: initial timeout %d sec\n",
 335                 omap_readl(wdev->base + OMAP_WATCHDOG_REV) & 0xFF,
 336                 timer_margin);
 337
 338         /* autogate OCP interface clock */
 339         omap_writel(0x01, wdev->base + OMAP_WATCHDOG_SYS_CONFIG);
 340
 341         omap_wdt_dev = pdev;
 342
 343         return 0;
 344
 345 fail:
 346         if (wdev) {
 347                 platform_set_drvdata(pdev, NULL);
 348                 if (wdev->armwdt_ck)
 349                         clk_put(wdev->armwdt_ck);
 350                 if (wdev->mpu_wdt_ick)
 351                         clk_put(wdev->mpu_wdt_ick);
 352                 if (wdev->mpu_wdt_fck)
 353                         clk_put(wdev->mpu_wdt_fck);
 354                 kfree(wdev);
 355         }
 356         if (mem) {
 357                 release_resource(mem);
 358         }
 359         return ret;
 360 }
 361
 362 static void omap_wdt_shutdown(struct platform_device *pdev)
 363 {
 364         struct omap_wdt_dev *wdev;
 365         wdev = platform_get_drvdata(pdev);
 366         omap_wdt_disable(wdev);
 367 }
 368
 369 static int omap_wdt_remove(struct platform_device *pdev)
 370 {
 371         struct omap_wdt_dev *wdev;
 372         wdev = platform_get_drvdata(pdev);
 373
 374         misc_deregister(&(wdev->omap_wdt_miscdev));
 375         release_resource(wdev->mem);
 376         platform_set_drvdata(pdev, NULL);
 377         if (wdev->armwdt_ck)
 378                 clk_put(wdev->armwdt_ck);
 379         if (wdev->mpu_wdt_ick)
 380                 clk_put(wdev->mpu_wdt_ick);
 381         if (wdev->mpu_wdt_fck)
 382                 clk_put(wdev->mpu_wdt_fck);
 383         kfree(wdev);
 384         omap_wdt_dev = NULL;
 385         return 0;
 386 }
 387
 388 #ifdef  CONFIG_PM
 389
 390 /* REVISIT ... not clear this is the best way to handle system suspend; and
 391  * it's very inappropriate for selective device suspend (e.g. suspending this
 392  * through sysfs rather than by stopping the watchdog daemon).  Also, this
 393  * may not play well enough with NOWAYOUT...
 394  */
 395
 396 static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 397 {
 398         struct omap_wdt_dev *wdev;
 399         wdev = platform_get_drvdata(pdev);
 400         if (wdev->omap_wdt_users)
 401                 omap_wdt_disable(wdev);
 402         return 0;
 403 }
 404
 405 static int omap_wdt_resume(struct platform_device *pdev)
 406 {
 407         struct omap_wdt_dev *wdev;
 408         wdev = platform_get_drvdata(pdev);
 409         if (wdev->omap_wdt_users) {
 410                 omap_wdt_enable(wdev);
 411                 omap_wdt_ping(wdev);
 412         }
 413         return 0;
 414 }
 415
 416 #else
 417 #define omap_wdt_suspend        NULL
 418 #define omap_wdt_resume         NULL
 419 #endif
 420
 421 static struct platform_driver omap_wdt_driver = {
 422         .probe          = omap_wdt_probe,
 423         .remove         = omap_wdt_remove,
 424         .shutdown       = omap_wdt_shutdown,
 425         .suspend        = omap_wdt_suspend,
 426         .resume         = omap_wdt_resume,
 427         .driver         = {
 428                 .owner  = THIS_MODULE,
 429                 .name   = "omap_wdt",
 430         },
 431 };
 432
 433 static int __init omap_wdt_init(void)
 434 {
 435         return platform_driver_register(&omap_wdt_driver);
 436 }
 437
 438 static void __exit omap_wdt_exit(void)
 439 {
 440         platform_driver_unregister(&omap_wdt_driver);
 441 }
 442
 443 module_init(omap_wdt_init);
 444 module_exit(omap_wdt_exit);
 445
 446 MODULE_AUTHOR("George G. Davis");
 447 MODULE_LICENSE("GPL");
 448 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);