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 unsigned timer_margin;
  53 module_param(timer_margin, uint, 0);
  54 MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)");
  55
  56 static int omap_wdt_users;
  57 static struct clk *armwdt_ck = NULL;
  58 static struct clk *mpu_wdt_ick = NULL;
  59 static struct clk *mpu_wdt_fck = NULL;
  60
  61 static unsigned int wdt_trgr_pattern = 0x1234;
  62
  63 static void omap_wdt_ping(void)
  64 {
  65         /* wait for posted write to complete */
  66         while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x08)
  67                 cpu_relax();
  68         wdt_trgr_pattern = ~wdt_trgr_pattern;
  69         omap_writel(wdt_trgr_pattern, (OMAP_WATCHDOG_TGR));
  70         /* wait for posted write to complete */
  71         while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x08)
  72                 cpu_relax();
  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                 cpu_relax();
  82         omap_writel(0x4444, OMAP_WATCHDOG_SPR);
  83         while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x10)
  84                 cpu_relax();
  85 }
  86
  87 static void omap_wdt_disable(void)
  88 {
  89         /* sequence required to disable watchdog */
  90         omap_writel(0xAAAA, OMAP_WATCHDOG_SPR); /* TIMER_MODE */
  91         while (omap_readl(OMAP_WATCHDOG_WPS) & 0x10)
  92                 cpu_relax();
  93         omap_writel(0x5555, OMAP_WATCHDOG_SPR); /* TIMER_MODE */
  94         while (omap_readl(OMAP_WATCHDOG_WPS) & 0x10)
  95                 cpu_relax();
  96 }
  97
  98 static void omap_wdt_adjust_timeout(unsigned new_timeout)
  99 {
 100         if (new_timeout < TIMER_MARGIN_MIN)
 101                 new_timeout = TIMER_MARGIN_DEFAULT;
 102         if (new_timeout > TIMER_MARGIN_MAX)
 103                 new_timeout = TIMER_MARGIN_MAX;
 104         timer_margin = new_timeout;
 105 }
 106
 107 static void omap_wdt_set_timeout(void)
 108 {
 109         u32 pre_margin = GET_WLDR_VAL(timer_margin);
 110
 111         /* just count up at 32 KHz */
 112         while (omap_readl(OMAP_WATCHDOG_WPS) & 0x04)
 113                 cpu_relax();
 114         omap_writel(pre_margin, OMAP_WATCHDOG_LDR);
 115         while (omap_readl(OMAP_WATCHDOG_WPS) & 0x04)
 116                 cpu_relax();
 117 }
 118
 119 /*
 120  *      Allow only one task to hold it open
 121  */
 122
 123 static int omap_wdt_open(struct inode *inode, struct file *file)
 124 {
 125         if (test_and_set_bit(1, (unsigned long *)&omap_wdt_users))
 126                 return -EBUSY;
 127
 128         if (cpu_is_omap16xx())
 129                 clk_enable(armwdt_ck);  /* Enable the clock */
 130
 131         if (cpu_is_omap24xx()) {
 132                 clk_enable(mpu_wdt_ick);    /* Enable the interface clock */
 133                 clk_enable(mpu_wdt_fck);    /* Enable the functional clock */
 134         }
 135
 136         /* initialize prescaler */
 137         while (omap_readl(OMAP_WATCHDOG_WPS) & 0x01)
 138                 cpu_relax();
 139         omap_writel((1 << 5) | (PTV << 2), OMAP_WATCHDOG_CNTRL);
 140         while (omap_readl(OMAP_WATCHDOG_WPS) & 0x01)
 141                 cpu_relax();
 142
 143         omap_wdt_set_timeout();
 144         omap_wdt_enable();
 145         return 0;
 146 }
 147
 148 static int omap_wdt_release(struct inode *inode, struct file *file)
 149 {
 150         /*
 151          *      Shut off the timer unless NOWAYOUT is defined.
 152          */
 153 #ifndef CONFIG_WATCHDOG_NOWAYOUT
 154         omap_wdt_disable();
 155
 156         if (cpu_is_omap16xx()) {
 157                 clk_disable(armwdt_ck); /* Disable the clock */
 158                 clk_put(armwdt_ck);
 159                 armwdt_ck = NULL;
 160         }
 161
 162         if (cpu_is_omap24xx()) {
 163                 clk_disable(mpu_wdt_ick);       /* Disable the clock */
 164                 clk_disable(mpu_wdt_fck);       /* Disable the clock */
 165                 clk_put(mpu_wdt_ick);
 166                 clk_put(mpu_wdt_fck);
 167                 mpu_wdt_ick = NULL;
 168                 mpu_wdt_fck = NULL;
 169         }
 170 #else
 171         printk(KERN_CRIT "omap_wdt: Unexpected close, not stopping!\n");
 172 #endif
 173         omap_wdt_users = 0;
 174         return 0;
 175 }
 176
 177 static ssize_t
 178 omap_wdt_write(struct file *file, const char __user *data,
 179                 size_t len, loff_t *ppos)
 180 {
 181         /* Refresh LOAD_TIME. */
 182         if (len)
 183                 omap_wdt_ping();
 184         return len;
 185 }
 186
 187 static int
 188 omap_wdt_ioctl(struct inode *inode, struct file *file,
 189         unsigned int cmd, unsigned long arg)
 190 {
 191         int new_margin;
 192         static struct watchdog_info ident = {
 193                 .identity = "OMAP Watchdog",
 194                 .options = WDIOF_SETTIMEOUT,
 195                 .firmware_version = 0,
 196         };
 197
 198         switch (cmd) {
 199         default:
 200                 return -ENOIOCTLCMD;
 201         case WDIOC_GETSUPPORT:
 202                 return copy_to_user((struct watchdog_info __user *)arg, &ident,
 203                                 sizeof(ident));
 204         case WDIOC_GETSTATUS:
 205                 return put_user(0, (int __user *)arg);
 206         case WDIOC_GETBOOTSTATUS:
 207                 if (cpu_is_omap16xx())
 208                         return put_user(omap_readw(ARM_SYSST),
 209                                         (int __user *)arg);
 210                 if (cpu_is_omap24xx())
 211                         return put_user(omap_prcm_get_reset_sources(),
 212                                         (int __user *)arg);
 213         case WDIOC_KEEPALIVE:
 214                 omap_wdt_ping();
 215                 return 0;
 216         case WDIOC_SETTIMEOUT:
 217                 if (get_user(new_margin, (int __user *)arg))
 218                         return -EFAULT;
 219                 omap_wdt_adjust_timeout(new_margin);
 220
 221                 omap_wdt_disable();
 222                 omap_wdt_set_timeout();
 223                 omap_wdt_enable();
 224
 225                 omap_wdt_ping();
 226                 /* Fall */
 227         case WDIOC_GETTIMEOUT:
 228                 return put_user(timer_margin, (int __user *)arg);
 229         }
 230 }
 231
 232 static const struct file_operations omap_wdt_fops = {
 233         .owner = THIS_MODULE,
 234         .write = omap_wdt_write,
 235         .ioctl = omap_wdt_ioctl,
 236         .open = omap_wdt_open,
 237         .release = omap_wdt_release,
 238 };
 239
 240 static struct miscdevice omap_wdt_miscdev = {
 241         .minor = WATCHDOG_MINOR,
 242         .name = "watchdog",
 243         .fops = &omap_wdt_fops
 244 };
 245
 246 static int __init omap_wdt_probe(struct platform_device *pdev)
 247 {
 248         struct resource *res, *mem;
 249         int ret;
 250
 251         /* reserve static register mappings */
 252         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 253         if (!res)
 254                 return -ENOENT;
 255
 256         mem = request_mem_region(res->start, res->end - res->start + 1,
 257                                  pdev->name);
 258         if (mem == NULL)
 259                 return -EBUSY;
 260
 261         platform_set_drvdata(pdev, mem);
 262
 263         omap_wdt_users = 0;
 264
 265         if (cpu_is_omap16xx()) {
 266                 armwdt_ck = clk_get(&pdev->dev, "armwdt_ck");
 267                 if (IS_ERR(armwdt_ck)) {
 268                         ret = PTR_ERR(armwdt_ck);
 269                         armwdt_ck = NULL;
 270                         goto fail;
 271                 }
 272         }
 273
 274         if (cpu_is_omap24xx()) {
 275                 mpu_wdt_ick = clk_get(&pdev->dev, "mpu_wdt_ick");
 276                 if (IS_ERR(mpu_wdt_ick)) {
 277                         ret = PTR_ERR(mpu_wdt_ick);
 278                         mpu_wdt_ick = NULL;
 279                         goto fail;
 280                 }
 281                 mpu_wdt_fck = clk_get(&pdev->dev, "mpu_wdt_fck");
 282                 if (IS_ERR(mpu_wdt_fck)) {
 283                         ret = PTR_ERR(mpu_wdt_fck);
 284                         mpu_wdt_fck = NULL;
 285                         goto fail;
 286                 }
 287         }
 288
 289         omap_wdt_disable();
 290         omap_wdt_adjust_timeout(timer_margin);
 291
 292         omap_wdt_miscdev.parent = &pdev->dev;
 293         ret = misc_register(&omap_wdt_miscdev);
 294         if (ret)
 295                 goto fail;
 296
 297         pr_info("OMAP Watchdog Timer: initial timeout %d sec\n", timer_margin);
 298
 299         /* autogate OCP interface clock */
 300         omap_writel(0x01, OMAP_WATCHDOG_SYS_CONFIG);
 301         return 0;
 302
 303 fail:
 304         if (armwdt_ck)
 305                 clk_put(armwdt_ck);
 306         if (mpu_wdt_ick)
 307                 clk_put(mpu_wdt_ick);
 308         if (mpu_wdt_fck)
 309                 clk_put(mpu_wdt_fck);
 310         release_resource(mem);
 311         return ret;
 312 }
 313
 314 static void omap_wdt_shutdown(struct platform_device *pdev)
 315 {
 316         omap_wdt_disable();
 317 }
 318
 319 static int omap_wdt_remove(struct platform_device *pdev)
 320 {
 321         struct resource *mem = platform_get_drvdata(pdev);
 322         misc_deregister(&omap_wdt_miscdev);
 323         release_resource(mem);
 324         if (armwdt_ck)
 325                 clk_put(armwdt_ck);
 326         if (mpu_wdt_ick)
 327                 clk_put(mpu_wdt_ick);
 328         if (mpu_wdt_fck)
 329                 clk_put(mpu_wdt_fck);
 330         return 0;
 331 }
 332
 333 #ifdef  CONFIG_PM
 334
 335 /* REVISIT ... not clear this is the best way to handle system suspend; and
 336  * it's very inappropriate for selective device suspend (e.g. suspending this
 337  * through sysfs rather than by stopping the watchdog daemon).  Also, this
 338  * may not play well enough with NOWAYOUT...
 339  */
 340
 341 static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 342 {
 343         if (omap_wdt_users)
 344                 omap_wdt_disable();
 345         return 0;
 346 }
 347
 348 static int omap_wdt_resume(struct platform_device *pdev)
 349 {
 350         if (omap_wdt_users) {
 351                 omap_wdt_enable();
 352                 omap_wdt_ping();
 353         }
 354         return 0;
 355 }
 356
 357 #else
 358 #define omap_wdt_suspend        NULL
 359 #define omap_wdt_resume         NULL
 360 #endif
 361
 362 static struct platform_driver omap_wdt_driver = {
 363         .probe          = omap_wdt_probe,
 364         .remove         = omap_wdt_remove,
 365         .shutdown       = omap_wdt_shutdown,
 366         .suspend        = omap_wdt_suspend,
 367         .resume         = omap_wdt_resume,
 368         .driver         = {
 369                 .owner  = THIS_MODULE,
 370                 .name   = "omap_wdt",
 371         },
 372 };
 373
 374 static int __init omap_wdt_init(void)
 375 {
 376         return platform_driver_register(&omap_wdt_driver);
 377 }
 378
 379 static void __exit omap_wdt_exit(void)
 380 {
 381         platform_driver_unregister(&omap_wdt_driver);
 382 }
 383
 384 module_init(omap_wdt_init);
 385 module_exit(omap_wdt_exit);
 386
 387 MODULE_AUTHOR("George G. Davis");
 388 MODULE_LICENSE("GPL");
 389 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);