drivers/char/watchdog/omap_wdt.c

   1 /*
   2  * linux/drivers/char/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/config.h>
  31 #include <linux/types.h>
  32 #include <linux/kernel.h>
  33 #include <linux/fs.h>
  34 #include <linux/mm.h>
  35 #include <linux/miscdevice.h>
  36 #include <linux/watchdog.h>
  37 #include <linux/reboot.h>
  38 #include <linux/smp_lock.h>
  39 #include <linux/init.h>
  40 #include <linux/err.h>
  41 #include <linux/platform_device.h>
  42 #include <linux/moduleparam.h>
  43 #include <linux/clk.h>
  44
  45 #include <asm/io.h>
  46 #include <asm/uaccess.h>
  47 #include <asm/hardware.h>
  48 #include <asm/bitops.h>
  49
  50 #include <asm/arch/prcm.h>
  51
  52 #include "omap_wdt.h"
  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 int omap_wdt_users;
  59 static struct clk *armwdt_ck = NULL;
  60 static struct clk *mpu_wdt_ick = NULL;
  61 static struct clk *mpu_wdt_fck = NULL;
  62
  63 static unsigned int wdt_trgr_pattern = 0x1234;
  64
  65 static void omap_wdt_ping(void)
  66 {
  67         while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x08) ;        /* wait for posted write to complete */
  68         wdt_trgr_pattern = ~wdt_trgr_pattern;
  69         omap_writel(wdt_trgr_pattern, (OMAP_WATCHDOG_TGR));
  70         while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x08) ;        /* wait for posted write to complete */
  71         /* reloaded WCRR from WLDR */
  72 }
  73
  74 static void omap_wdt_enable(void)
  75 {
  76         /* Sequence to enable the watchdog */
  77         omap_writel(0xBBBB, OMAP_WATCHDOG_SPR);
  78         while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x10) ;
  79         omap_writel(0x4444, OMAP_WATCHDOG_SPR);
  80         while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x10) ;
  81 }
  82
  83 static void omap_wdt_disable(void)
  84 {
  85         /* sequence required to disable watchdog */
  86         omap_writel(0xAAAA, OMAP_WATCHDOG_SPR); /* TIMER_MODE */
  87         while (omap_readl(OMAP_WATCHDOG_WPS) & 0x10) ;
  88         omap_writel(0x5555, OMAP_WATCHDOG_SPR); /* TIMER_MODE */
  89         while (omap_readl(OMAP_WATCHDOG_WPS) & 0x10) ;
  90 }
  91
  92 static void omap_wdt_adjust_timeout(unsigned new_timeout)
  93 {
  94         if (new_timeout < TIMER_MARGIN_MIN)
  95                 new_timeout = TIMER_MARGIN_DEFAULT;
  96         if (new_timeout > TIMER_MARGIN_MAX)
  97                 new_timeout = TIMER_MARGIN_MAX;
  98         timer_margin = new_timeout;
  99 }
 100
 101 static void omap_wdt_set_timeout(void)
 102 {
 103         u32 pre_margin = GET_WLDR_VAL(timer_margin);
 104
 105         /* just count up at 32 KHz */
 106         while (omap_readl(OMAP_WATCHDOG_WPS) & 0x04)
 107                 continue;
 108         omap_writel(pre_margin, OMAP_WATCHDOG_LDR);
 109         while (omap_readl(OMAP_WATCHDOG_WPS) & 0x04)
 110                 continue;
 111 }
 112
 113 /*
 114  *      Allow only one task to hold it open
 115  */
 116
 117 static int omap_wdt_open(struct inode *inode, struct file *file)
 118 {
 119         if (test_and_set_bit(1, (unsigned long *)&omap_wdt_users))
 120                 return -EBUSY;
 121
 122         if (cpu_is_omap16xx()) {
 123                 clk_enable(armwdt_ck);  /* Enable the clock */
 124         }
 125
 126         if (cpu_is_omap24xx()) {
 127                 clk_enable(mpu_wdt_ick);        /* Enable the interface clock */
 128                 clk_enable(mpu_wdt_fck);        /* Enable the functional clock */
 129         }
 130
 131         /* initialize prescaler */
 132         while (omap_readl(OMAP_WATCHDOG_WPS) & 0x01)
 133                 continue;
 134         omap_writel((1 << 5) | (PTV << 2), OMAP_WATCHDOG_CNTRL);
 135         while (omap_readl(OMAP_WATCHDOG_WPS) & 0x01)
 136                 continue;
 137
 138         omap_wdt_set_timeout();
 139         omap_wdt_enable();
 140         return 0;
 141 }
 142
 143 static int omap_wdt_release(struct inode *inode, struct file *file)
 144 {
 145         /*
 146          *      Shut off the timer unless NOWAYOUT is defined.
 147          */
 148 #ifndef CONFIG_WATCHDOG_NOWAYOUT
 149         omap_wdt_disable();
 150
 151         if (cpu_is_omap16xx()) {
 152                 clk_disable(armwdt_ck); /* Disable the clock */
 153                 clk_put(armwdt_ck);
 154                 armwdt_ck = NULL;
 155         }
 156
 157         if (cpu_is_omap24xx()) {
 158                 clk_disable(mpu_wdt_ick);       /* Disable the clock */
 159                 clk_disable(mpu_wdt_fck);       /* Disable the clock */
 160                 clk_put(mpu_wdt_ick);
 161                 clk_put(mpu_wdt_fck);
 162                 mpu_wdt_ick = NULL;
 163                 mpu_wdt_fck = NULL;
 164         }
 165 #else
 166         printk(KERN_CRIT "omap_wdt: Unexpected close, not stopping!\n");
 167 #endif
 168         omap_wdt_users = 0;
 169         return 0;
 170 }
 171
 172 static ssize_t
 173 omap_wdt_write(struct file *file, const char __user * data,
 174         size_t len, loff_t * ppos)
 175 {
 176         /* Refresh LOAD_TIME. */
 177         if (len)
 178                 omap_wdt_ping();
 179         return len;
 180 }
 181
 182 static int
 183 omap_wdt_ioctl(struct inode *inode, struct file *file,
 184         unsigned int cmd, unsigned long arg)
 185 {
 186         int new_margin;
 187         static struct watchdog_info ident = {
 188                 .identity = "OMAP Watchdog",
 189                 .options = WDIOF_SETTIMEOUT,
 190                 .firmware_version = 0,
 191         };
 192
 193         switch (cmd) {
 194         default:
 195                 return -ENOIOCTLCMD;
 196         case WDIOC_GETSUPPORT:
 197                 return copy_to_user((struct watchdog_info __user *)arg, &ident,
 198         sizeof(ident));
 199         case WDIOC_GETSTATUS:
 200                 return put_user(0, (int __user *)arg);
 201         case WDIOC_GETBOOTSTATUS:
 202                 if (cpu_is_omap16xx())
 203                         return put_user(omap_readw(ARM_SYSST),
 204                                         (int __user *)arg);
 205                 if (cpu_is_omap24xx())
 206                         return put_user(omap_prcm_get_reset_sources(),
 207                                         (int __user *)arg);
 208         case WDIOC_KEEPALIVE:
 209                 omap_wdt_ping();
 210                 return 0;
 211         case WDIOC_SETTIMEOUT:
 212                 if (get_user(new_margin, (int __user *)arg))
 213                         return -EFAULT;
 214                 omap_wdt_adjust_timeout(new_margin);
 215
 216                 omap_wdt_disable();
 217                 omap_wdt_set_timeout();
 218                 omap_wdt_enable();
 219
 220                 omap_wdt_ping();
 221                 /* Fall */
 222         case WDIOC_GETTIMEOUT:
 223                 return put_user(timer_margin, (int __user *)arg);
 224         }
 225 }
 226
 227 static struct file_operations omap_wdt_fops = {
 228         .owner = THIS_MODULE,
 229         .write = omap_wdt_write,
 230         .ioctl = omap_wdt_ioctl,
 231         .open = omap_wdt_open,
 232         .release = omap_wdt_release,
 233 };
 234
 235 static struct miscdevice omap_wdt_miscdev = {
 236         .minor = WATCHDOG_MINOR,
 237         .name = "watchdog",
 238         .fops = &omap_wdt_fops
 239 };
 240
 241 static int __init omap_wdt_probe(struct platform_device *pdev)
 242 {
 243         struct resource *res, *mem;
 244         int ret;
 245
 246         /* reserve static register mappings */
 247         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 248         if (!res)
 249                 return -ENOENT;
 250
 251         mem = request_mem_region(res->start, res->end - res->start + 1,
 252                                  pdev->name);
 253         if (mem == NULL)
 254                 return -EBUSY;
 255
 256         platform_set_drvdata(pdev, mem);
 257
 258         omap_wdt_users = 0;
 259
 260         if (cpu_is_omap16xx()) {
 261                 armwdt_ck = clk_get(&pdev->dev, "armwdt_ck");
 262                 if (IS_ERR(armwdt_ck)) {
 263                         ret = PTR_ERR(armwdt_ck);
 264                         armwdt_ck = NULL;
 265                         goto fail;
 266                 }
 267         }
 268
 269         if (cpu_is_omap24xx()) {
 270                 mpu_wdt_ick = clk_get(&pdev->dev, "mpu_wdt_ick");
 271                 if (IS_ERR(mpu_wdt_ick)) {
 272                         ret = PTR_ERR(mpu_wdt_ick);
 273                         mpu_wdt_ick = NULL;
 274                         goto fail;
 275                 }
 276                 mpu_wdt_fck = clk_get(&pdev->dev, "mpu_wdt_fck");
 277                 if (IS_ERR(mpu_wdt_fck)) {
 278                         ret = PTR_ERR(mpu_wdt_fck);
 279                         mpu_wdt_fck = NULL;
 280                         goto fail;
 281                 }
 282         }
 283
 284         omap_wdt_disable();
 285         omap_wdt_adjust_timeout(timer_margin);
 286
 287         omap_wdt_miscdev.dev = &pdev->dev;
 288         ret = misc_register(&omap_wdt_miscdev);
 289         if (ret)
 290                 goto fail;
 291
 292         pr_info("OMAP Watchdog Timer: initial timeout %d sec\n", timer_margin);
 293
 294         /* autogate OCP interface clock */
 295         omap_writel(0x01, OMAP_WATCHDOG_SYS_CONFIG);
 296         return 0;
 297
 298 fail:
 299         if (armwdt_ck)
 300                 clk_put(armwdt_ck);
 301         if (mpu_wdt_ick)
 302                 clk_put(mpu_wdt_ick);
 303         if (mpu_wdt_fck)
 304                 clk_put(mpu_wdt_fck);
 305         release_resource(mem);
 306         return ret;
 307 }
 308
 309 static void omap_wdt_shutdown(struct platform_device *pdev)
 310 {
 311         omap_wdt_disable();
 312 }
 313
 314 static int omap_wdt_remove(struct platform_device *pdev)
 315 {
 316         struct resource *mem = platform_get_drvdata(pdev);
 317         misc_deregister(&omap_wdt_miscdev);
 318         release_resource(mem);
 319         if (armwdt_ck)
 320                 clk_put(armwdt_ck);
 321         if (mpu_wdt_ick)
 322                 clk_put(mpu_wdt_ick);
 323         if (mpu_wdt_fck)
 324                 clk_put(mpu_wdt_fck);
 325         return 0;
 326 }
 327
 328 #ifdef  CONFIG_PM
 329
 330 /* REVISIT ... not clear this is the best way to handle system suspend; and
 331  * it's very inappropriate for selective device suspend (e.g. suspending this
 332  * through sysfs rather than by stopping the watchdog daemon).  Also, this
 333  * may not play well enough with NOWAYOUT...
 334  */
 335
 336 static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 337 {
 338         if (omap_wdt_users)
 339                 omap_wdt_disable();
 340         return 0;
 341 }
 342
 343 static int omap_wdt_resume(struct platform_device *pdev)
 344 {
 345         if (omap_wdt_users) {
 346                 omap_wdt_enable();
 347                 omap_wdt_ping();
 348         }
 349         return 0;
 350 }
 351
 352 #else
 353 #define omap_wdt_suspend        NULL
 354 #define omap_wdt_resume         NULL
 355 #endif
 356
 357 static struct platform_driver omap_wdt_driver = {
 358         .probe          = omap_wdt_probe,
 359         .remove         = omap_wdt_remove,
 360         .shutdown       = omap_wdt_shutdown,
 361         .suspend        = omap_wdt_suspend,
 362         .resume         = omap_wdt_resume,
 363         .driver         = {
 364                 .owner  = THIS_MODULE,
 365                 .name   = "omap_wdt",
 366         },
 367 };
 368
 369 static int __init omap_wdt_init(void)
 370 {
 371         return platform_driver_register(&omap_wdt_driver);
 372 }
 373
 374 static void __exit omap_wdt_exit(void)
 375 {
 376         platform_driver_unregister(&omap_wdt_driver);
 377 }
 378
 379 module_init(omap_wdt_init);
 380 module_exit(omap_wdt_exit);
 381
 382 MODULE_AUTHOR("George G. Davis");
 383 MODULE_LICENSE("GPL");
 384 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);