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