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
  44 #include <asm/io.h>
  45 #include <asm/uaccess.h>
  46 #include <asm/hardware.h>
  47 #include <asm/bitops.h>
  48 #include <asm/hardware/clock.h>
  49
  50 #ifdef CONFIG_ARCH_OMAP24XX
  51 #include <asm/arch/prcm.h>
  52 #endif
  53
  54 #include "omap_wdt.h"
  55
  56 static unsigned timer_margin;
  57 module_param(timer_margin, uint, 0);
  58 MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)");
  59
  60 static int omap_wdt_users;
  61 static struct clk *armwdt_ck = NULL;
  62 static struct clk *mpu_wdt_ick = NULL;
  63 static struct clk *mpu_wdt_fck = NULL;
  64
  65 static unsigned int wdt_trgr_pattern = 0x1234;
  66
  67 static void omap_wdt_ping(void)
  68 {
  69         while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x08) ;        /* wait for posted write to complete */
  70         wdt_trgr_pattern = ~wdt_trgr_pattern;
  71         omap_writel(wdt_trgr_pattern, (OMAP_WATCHDOG_TGR));
  72         while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x08) ;        /* wait for posted write to complete */
  73         /* reloaded WCRR from WLDR */
  74 }
  75
  76 static void omap_wdt_enable(void)
  77 {
  78         /* Sequence to enable the watchdog */
  79         omap_writel(0xBBBB, OMAP_WATCHDOG_SPR);
  80         while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x10) ;
  81         omap_writel(0x4444, OMAP_WATCHDOG_SPR);
  82         while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x10) ;
  83 }
  84
  85 static void omap_wdt_disable(void)
  86 {
  87         /* sequence required to disable watchdog */
  88         omap_writel(0xAAAA, OMAP_WATCHDOG_SPR); /* TIMER_MODE */
  89         while (omap_readl(OMAP_WATCHDOG_WPS) & 0x10) ;
  90         omap_writel(0x5555, OMAP_WATCHDOG_SPR); /* TIMER_MODE */
  91         while (omap_readl(OMAP_WATCHDOG_WPS) & 0x10) ;
  92 }
  93
  94 static void omap_wdt_adjust_timeout(unsigned new_timeout)
  95 {
  96         if (new_timeout < TIMER_MARGIN_MIN)
  97                 new_timeout = TIMER_MARGIN_DEFAULT;
  98         if (new_timeout > TIMER_MARGIN_MAX)
  99                 new_timeout = TIMER_MARGIN_MAX;
 100         timer_margin = new_timeout;
 101 }
 102
 103 static void omap_wdt_set_timeout(void)
 104 {
 105         u32 pre_margin = GET_WLDR_VAL(timer_margin);
 106
 107         /* just count up at 32 KHz */
 108         while (omap_readl(OMAP_WATCHDOG_WPS) & 0x04)
 109                 continue;
 110         omap_writel(pre_margin, OMAP_WATCHDOG_LDR);
 111         while (omap_readl(OMAP_WATCHDOG_WPS) & 0x04)
 112                 continue;
 113 }
 114
 115 /*
 116  *      Allow only one task to hold it open
 117  */
 118
 119 static int omap_wdt_open(struct inode *inode, struct file *file)
 120 {
 121         if (test_and_set_bit(1, (unsigned long *)&omap_wdt_users))
 122                 return -EBUSY;
 123
 124         if (cpu_is_omap16xx()) {
 125                 clk_use(armwdt_ck);     /* Enable the clock */
 126         }
 127
 128         if (cpu_is_omap24xx()) {
 129                 clk_use(mpu_wdt_ick);   /* Enable the interface clock */
 130                 clk_use(mpu_wdt_fck);   /* Enable the functional clock */
 131         }
 132
 133         /* initialize prescaler */
 134         while (omap_readl(OMAP_WATCHDOG_WPS) & 0x01)
 135                 continue;
 136         omap_writel((1 << 5) | (PTV << 2), OMAP_WATCHDOG_CNTRL);
 137         while (omap_readl(OMAP_WATCHDOG_WPS) & 0x01)
 138                 continue;
 139
 140         omap_wdt_set_timeout();
 141         omap_wdt_enable();
 142         return 0;
 143 }
 144
 145 static int omap_wdt_release(struct inode *inode, struct file *file)
 146 {
 147         /*
 148          *      Shut off the timer unless NOWAYOUT is defined.
 149          */
 150 #ifndef CONFIG_WATCHDOG_NOWAYOUT
 151         omap_wdt_disable();
 152
 153         if (cpu_is_omap16xx()) {
 154                 clk_unuse(armwdt_ck);   /* Disable the clock */
 155                 clk_put(armwdt_ck);
 156                 armwdt_ck = NULL;
 157         }
 158
 159         if (cpu_is_omap24xx()) {
 160                 clk_unuse(mpu_wdt_ick); /* Disable the clock */
 161                 clk_unuse(mpu_wdt_fck); /* Disable the clock */
 162                 clk_put(mpu_wdt_ick);
 163                 clk_put(mpu_wdt_fck);
 164                 mpu_wdt_ick = NULL;
 165                 mpu_wdt_fck = NULL;
 166         }
 167 #else
 168         printk(KERN_CRIT "omap_wdt: Unexpected close, not stopping!\n");
 169 #endif
 170         omap_wdt_users = 0;
 171         return 0;
 172 }
 173
 174 static ssize_t
 175 omap_wdt_write(struct file *file, const char __user * data,
 176         size_t len, loff_t * ppos)
 177 {
 178         /* Refresh LOAD_TIME. */
 179         if (len)
 180                 omap_wdt_ping();
 181         return len;
 182 }
 183
 184 static int
 185 omap_wdt_ioctl(struct inode *inode, struct file *file,
 186         unsigned int cmd, unsigned long arg)
 187 {
 188         int new_margin;
 189         static struct watchdog_info ident = {
 190                 .identity = "OMAP Watchdog",
 191                 .options = WDIOF_SETTIMEOUT,
 192                 .firmware_version = 0,
 193         };
 194
 195         switch (cmd) {
 196         default:
 197                 return -ENOIOCTLCMD;
 198         case WDIOC_GETSUPPORT:
 199                 return copy_to_user((struct watchdog_info __user *)arg, &ident,
 200         sizeof(ident));
 201         case WDIOC_GETSTATUS:
 202                 return put_user(0, (int __user *)arg);
 203         case WDIOC_GETBOOTSTATUS:
 204                 if (cpu_is_omap16xx())
 205                         return put_user(omap_readw(ARM_SYSST),
 206                                         (int __user *)arg);
 207                 if (cpu_is_omap24xx())
 208                         return put_user(RM_RSTST_WKUP, (int __user *)arg);
 209         case WDIOC_KEEPALIVE:
 210                 omap_wdt_ping();
 211                 return 0;
 212         case WDIOC_SETTIMEOUT:
 213                 if (get_user(new_margin, (int __user *)arg))
 214                         return -EFAULT;
 215                 omap_wdt_adjust_timeout(new_margin);
 216
 217                 omap_wdt_disable();
 218                 omap_wdt_set_timeout();
 219                 omap_wdt_enable();
 220
 221                 omap_wdt_ping();
 222                 /* Fall */
 223         case WDIOC_GETTIMEOUT:
 224                 return put_user(timer_margin, (int __user *)arg);
 225         }
 226 }
 227
 228 static struct file_operations omap_wdt_fops = {
 229         .owner = THIS_MODULE,
 230         .write = omap_wdt_write,
 231         .ioctl = omap_wdt_ioctl,
 232         .open = omap_wdt_open,
 233         .release = omap_wdt_release,
 234 };
 235
 236 static struct miscdevice omap_wdt_miscdev = {
 237         .minor = WATCHDOG_MINOR,
 238         .name = "watchdog",
 239         .fops = &omap_wdt_fops
 240 };
 241
 242 static int __init omap_wdt_probe(struct device *dev)
 243 {
 244         struct platform_device *pdev = to_platform_device(dev);
 245         struct resource *res, *mem;
 246         int ret;
 247
 248         /* reserve static register mappings */
 249         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 250         if (!res)
 251                 return -ENOENT;
 252
 253         mem = request_mem_region(res->start, res->end - res->start + 1,
 254                                  pdev->name);
 255         if (mem == NULL)
 256                 return -EBUSY;
 257
 258         dev_set_drvdata(dev, mem);
 259
 260         omap_wdt_users = 0;
 261
 262         if (cpu_is_omap16xx()) {
 263                 armwdt_ck = clk_get(dev, "armwdt_ck");
 264                 if (IS_ERR(armwdt_ck)) {
 265                         ret = PTR_ERR(armwdt_ck);
 266                         armwdt_ck = NULL;
 267                         goto fail;
 268                 }
 269         }
 270
 271         if (cpu_is_omap24xx()) {
 272                 mpu_wdt_ick = clk_get(dev, "mpu_wdt_ick");
 273                 if (IS_ERR(mpu_wdt_ick)) {
 274                         ret = PTR_ERR(mpu_wdt_ick);
 275                         mpu_wdt_ick = NULL;
 276                         goto fail;
 277                 }
 278                 mpu_wdt_fck = clk_get(dev, "mpu_wdt_fck");
 279                 if (IS_ERR(mpu_wdt_fck)) {
 280                         ret = PTR_ERR(mpu_wdt_fck);
 281                         mpu_wdt_fck = NULL;
 282                         goto fail;
 283                 }
 284         }
 285
 286         omap_wdt_disable();
 287         omap_wdt_adjust_timeout(timer_margin);
 288
 289         omap_wdt_miscdev.dev = dev;
 290         ret = misc_register(&omap_wdt_miscdev);
 291         if (ret)
 292                 goto fail;
 293
 294         pr_info("OMAP Watchdog Timer: initial timeout %d sec\n", timer_margin);
 295
 296         /* autogate OCP interface clock */
 297         omap_writel(0x01, OMAP_WATCHDOG_SYS_CONFIG);
 298         return 0;
 299
 300 fail:
 301         if (armwdt_ck)
 302                 clk_put(armwdt_ck);
 303         if (mpu_wdt_ick)
 304                 clk_put(mpu_wdt_ick);
 305         if (mpu_wdt_fck)
 306                 clk_put(mpu_wdt_fck);
 307         release_resource(mem);
 308         return ret;
 309 }
 310
 311 static void omap_wdt_shutdown(struct device *dev)
 312 {
 313         omap_wdt_disable();
 314 }
 315
 316 static int __exit omap_wdt_remove(struct device *dev)
 317 {
 318         struct resource *mem = dev_get_drvdata(dev);
 319         misc_deregister(&omap_wdt_miscdev);
 320         release_resource(mem);
 321         if (armwdt_ck)
 322                 clk_put(armwdt_ck);
 323         if (mpu_wdt_ick)
 324                 clk_put(mpu_wdt_ick);
 325         if (mpu_wdt_fck)
 326                 clk_put(mpu_wdt_fck);
 327         return 0;
 328 }
 329
 330 #ifdef  CONFIG_PM
 331
 332 /* REVISIT ... not clear this is the best way to handle system suspend; and
 333  * it's very inappropriate for selective device suspend (e.g. suspending this
 334  * through sysfs rather than by stopping the watchdog daemon).  Also, this
 335  * may not play well enough with NOWAYOUT...
 336  */
 337
 338 static int omap_wdt_suspend(struct device *dev, pm_message_t state)
 339 {
 340         if (omap_wdt_users)
 341                 omap_wdt_disable();
 342         return 0;
 343 }
 344
 345 static int omap_wdt_resume(struct device *dev)
 346 {
 347         if (omap_wdt_users) {
 348                 omap_wdt_enable();
 349                 omap_wdt_ping();
 350         }
 351         return 0;
 352 }
 353
 354 #else
 355 #define omap_wdt_suspend        NULL
 356 #define omap_wdt_resume         NULL
 357 #endif
 358
 359 static struct device_driver omap_wdt_driver = {
 360         .name = "omap_wdt",
 361         .bus = &platform_bus_type,
 362         .probe = omap_wdt_probe,
 363         .shutdown = omap_wdt_shutdown,
 364         .remove = __exit_p(omap_wdt_remove),
 365         .suspend = omap_wdt_suspend,
 366         .resume = omap_wdt_resume,
 367 };
 368
 369 static int __init omap_wdt_init(void)
 370 {
 371         return driver_register(&omap_wdt_driver);
 372 }
 373
 374 static void __exit omap_wdt_exit(void)
 375 {
 376         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);