target/linux/ramips/files-3.7/drivers/watchdog/ramips_wdt.c

   1 /*
   2  * Ralink RT288X/RT305X built-in hardware watchdog timer
   3  *
   4  * Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org>
   5  *
   6  * This driver was based on: drivers/watchdog/ixp4xx_wdt.c
   7  *      Author: Deepak Saxena <dsaxena@plexity.net>
   8  *      Copyright 2004 (c) MontaVista, Software, Inc.
   9  *
  10  * which again was based on sa1100 driver,
  11  *      Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
  12  *
  13  * parts of the driver are based on Ralink's 2.6.21 BSP
  14  *
  15  * This program is free software; you can redistribute it and/or modify it
  16  * under the terms of the GNU General Public License version 2 as published
  17  * by the Free Software Foundation.
  18  */
  19
  20 #include <linux/bitops.h>
  21 #include <linux/errno.h>
  22 #include <linux/fs.h>
  23 #include <linux/init.h>
  24 #include <linux/kernel.h>
  25 #include <linux/miscdevice.h>
  26 #include <linux/module.h>
  27 #include <linux/moduleparam.h>
  28 #include <linux/platform_device.h>
  29 #include <linux/types.h>
  30 #include <linux/watchdog.h>
  31 #include <linux/clk.h>
  32 #include <linux/err.h>
  33
  34 #define DRIVER_NAME     "ramips-wdt"
  35
  36 #define RAMIPS_WDT_TIMEOUT              0       /* seconds */
  37 #define RAMIPS_WDT_PRESCALE             65536
  38
  39 #define TIMER_REG_TMRSTAT               0x00
  40 #define TIMER_REG_TMR1LOAD              0x20
  41 #define TIMER_REG_TMR1CTL               0x28
  42
  43 #define TMRSTAT_TMR1RST                 BIT(5)
  44
  45 #define TMR1CTL_ENABLE                  BIT(7)
  46 #define TMR1CTL_MODE_SHIFT              4
  47 #define TMR1CTL_MODE_MASK               0x3
  48 #define TMR1CTL_MODE_FREE_RUNNING       0x0
  49 #define TMR1CTL_MODE_PERIODIC           0x1
  50 #define TMR1CTL_MODE_TIMEOUT            0x2
  51 #define TMR1CTL_MODE_WDT                0x3
  52 #define TMR1CTL_PRESCALE_MASK           0xf
  53 #define TMR1CTL_PRESCALE_65536          0xf
  54
  55 static int nowayout = WATCHDOG_NOWAYOUT;
  56 module_param(nowayout, int, 0);
  57 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
  58                            "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  59
  60 static int ramips_wdt_timeout = RAMIPS_WDT_TIMEOUT;
  61 module_param_named(timeout, ramips_wdt_timeout, int, 0);
  62 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds, 0 means use maximum "
  63                           "(default=" __MODULE_STRING(RAMIPS_WDT_TIMEOUT) "s)");
  64
  65 static unsigned long ramips_wdt_flags;
  66
  67 #define WDT_FLAGS_BUSY          0
  68 #define WDT_FLAGS_EXPECT_CLOSE  1
  69
  70 static struct clk *ramips_wdt_clk;
  71 static unsigned long ramips_wdt_freq;
  72 static int ramips_wdt_max_timeout;
  73 static void __iomem *ramips_wdt_base;
  74
  75 static inline void ramips_wdt_wr(unsigned reg, u32 val)
  76 {
  77         __raw_writel(val, ramips_wdt_base + reg);
  78 }
  79
  80 static inline u32 ramips_wdt_rr(unsigned reg)
  81 {
  82         return __raw_readl(ramips_wdt_base + reg);
  83 }
  84
  85 static inline void ramips_wdt_keepalive(void)
  86 {
  87         ramips_wdt_wr(TIMER_REG_TMR1LOAD, ramips_wdt_timeout * ramips_wdt_freq);
  88 }
  89
  90 static inline void ramips_wdt_enable(void)
  91 {
  92         u32 t;
  93
  94         ramips_wdt_keepalive();
  95
  96         t = ramips_wdt_rr(TIMER_REG_TMR1CTL);
  97         t |= TMR1CTL_ENABLE;
  98         ramips_wdt_wr(TIMER_REG_TMR1CTL, t);
  99 }
 100
 101 static inline void ramips_wdt_disable(void)
 102 {
 103         u32 t;
 104
 105         ramips_wdt_keepalive();
 106
 107         t = ramips_wdt_rr(TIMER_REG_TMR1CTL);
 108         t &= ~TMR1CTL_ENABLE;
 109         ramips_wdt_wr(TIMER_REG_TMR1CTL, t);
 110 }
 111
 112 static int ramips_wdt_set_timeout(int val)
 113 {
 114         if (val < 1 || val > ramips_wdt_max_timeout) {
 115                 pr_warn(DRIVER_NAME
 116                         ": timeout value %d must be 0 < timeout <= %d, using %d\n",
 117                         val, ramips_wdt_max_timeout, ramips_wdt_timeout);
 118                 return -EINVAL;
 119         }
 120
 121         ramips_wdt_timeout = val;
 122         ramips_wdt_keepalive();
 123
 124         return 0;
 125 }
 126
 127 static int ramips_wdt_open(struct inode *inode, struct file *file)
 128 {
 129         u32 t;
 130
 131         if (test_and_set_bit(WDT_FLAGS_BUSY, &ramips_wdt_flags))
 132                 return -EBUSY;
 133
 134         clear_bit(WDT_FLAGS_EXPECT_CLOSE, &ramips_wdt_flags);
 135
 136         t = ramips_wdt_rr(TIMER_REG_TMR1CTL);
 137         t &= ~(TMR1CTL_MODE_MASK << TMR1CTL_MODE_SHIFT |
 138                TMR1CTL_PRESCALE_MASK);
 139         t |= (TMR1CTL_MODE_WDT << TMR1CTL_MODE_SHIFT |
 140               TMR1CTL_PRESCALE_65536);
 141         ramips_wdt_wr(TIMER_REG_TMR1CTL, t);
 142
 143         ramips_wdt_enable();
 144
 145         return nonseekable_open(inode, file);
 146 }
 147
 148 static int ramips_wdt_release(struct inode *inode, struct file *file)
 149 {
 150         if (test_bit(WDT_FLAGS_EXPECT_CLOSE, &ramips_wdt_flags))
 151                 ramips_wdt_disable();
 152         else {
 153                 pr_crit(DRIVER_NAME ": device closed unexpectedly, "
 154                         "watchdog timer will not stop!\n");
 155                 ramips_wdt_keepalive();
 156         }
 157
 158         clear_bit(WDT_FLAGS_BUSY, &ramips_wdt_flags);
 159         clear_bit(WDT_FLAGS_EXPECT_CLOSE, &ramips_wdt_flags);
 160
 161         return 0;
 162 }
 163
 164 static ssize_t ramips_wdt_write(struct file *file, const char *data,
 165                                 size_t len, loff_t *ppos)
 166 {
 167         if (len) {
 168                 if (!nowayout) {
 169                         size_t i;
 170
 171                         clear_bit(WDT_FLAGS_EXPECT_CLOSE, &ramips_wdt_flags);
 172
 173                         for (i = 0; i != len; i++) {
 174                                 char c;
 175
 176                                 if (get_user(c, data + i))
 177                                         return -EFAULT;
 178
 179                                 if (c == 'V')
 180                                         set_bit(WDT_FLAGS_EXPECT_CLOSE,
 181                                                 &ramips_wdt_flags);
 182                         }
 183                 }
 184
 185                 ramips_wdt_keepalive();
 186         }
 187
 188         return len;
 189 }
 190
 191 static const struct watchdog_info ramips_wdt_info = {
 192         .options                = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
 193                                   WDIOF_MAGICCLOSE,
 194         .firmware_version       = 0,
 195         .identity               = "RAMIPS watchdog",
 196 };
 197
 198 static long ramips_wdt_ioctl(struct file *file, unsigned int cmd,
 199                             unsigned long arg)
 200 {
 201         void __user *argp = (void __user *)arg;
 202         int __user *p = argp;
 203         int err;
 204         int t;
 205
 206         switch (cmd) {
 207         case WDIOC_GETSUPPORT:
 208                 err = copy_to_user(argp, &ramips_wdt_info,
 209                                    sizeof(ramips_wdt_info)) ? -EFAULT : 0;
 210                 break;
 211
 212         case WDIOC_GETSTATUS:
 213                 err = put_user(0, p);
 214                 break;
 215
 216         case WDIOC_KEEPALIVE:
 217                 ramips_wdt_keepalive();
 218                 err = 0;
 219                 break;
 220
 221         case WDIOC_SETTIMEOUT:
 222                 err = get_user(t, p);
 223                 if (err)
 224                         break;
 225
 226                 err = ramips_wdt_set_timeout(t);
 227                 if (err)
 228                         break;
 229
 230                 /* fallthrough */
 231         case WDIOC_GETTIMEOUT:
 232                 err = put_user(ramips_wdt_timeout, p);
 233                 break;
 234
 235         default:
 236                 err = -ENOTTY;
 237                 break;
 238         }
 239
 240         return err;
 241 }
 242
 243 static const struct file_operations ramips_wdt_fops = {
 244         .owner          = THIS_MODULE,
 245         .llseek         = no_llseek,
 246         .write          = ramips_wdt_write,
 247         .unlocked_ioctl = ramips_wdt_ioctl,
 248         .open           = ramips_wdt_open,
 249         .release        = ramips_wdt_release,
 250 };
 251
 252 static struct miscdevice ramips_wdt_miscdev = {
 253         .minor = WATCHDOG_MINOR,
 254         .name = "watchdog",
 255         .fops = &ramips_wdt_fops,
 256 };
 257
 258 static int ramips_wdt_probe(struct platform_device *pdev)
 259 {
 260         struct resource *res;
 261         int err;
 262
 263         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 264         if (!res) {
 265                 dev_err(&pdev->dev, "no memory resource found\n");
 266                 return -EINVAL;
 267         }
 268
 269         ramips_wdt_base = ioremap(res->start, resource_size(res));
 270         if (!ramips_wdt_base)
 271                 return -ENOMEM;
 272
 273         ramips_wdt_clk = clk_get(&pdev->dev, "wdt");
 274         if (IS_ERR(ramips_wdt_clk)) {
 275                 err = PTR_ERR(ramips_wdt_clk);
 276                 goto err_unmap;
 277         }
 278
 279         err = clk_enable(ramips_wdt_clk);
 280         if (err)
 281                 goto err_clk_put;
 282
 283         ramips_wdt_freq = clk_get_rate(ramips_wdt_clk) / RAMIPS_WDT_PRESCALE;
 284         if (!ramips_wdt_freq) {
 285                 err = -EINVAL;
 286                 goto err_clk_disable;
 287         }
 288
 289         ramips_wdt_max_timeout = (0xfffful / ramips_wdt_freq);
 290         if (ramips_wdt_timeout < 1 ||
 291             ramips_wdt_timeout > ramips_wdt_max_timeout) {
 292                 ramips_wdt_timeout = ramips_wdt_max_timeout;
 293                 dev_info(&pdev->dev,
 294                         "timeout value must be 0 < timeout <= %d, using %d\n",
 295                         ramips_wdt_max_timeout, ramips_wdt_timeout);
 296         }
 297
 298         err = misc_register(&ramips_wdt_miscdev);
 299         if (err) {
 300                 dev_err(&pdev->dev,
 301                         "unable to register misc device, err=%d\n", err);
 302                 goto err_clk_disable;
 303         }
 304
 305         return 0;
 306
 307 err_clk_disable:
 308         clk_disable(ramips_wdt_clk);
 309 err_clk_put:
 310         clk_put(ramips_wdt_clk);
 311 err_unmap:
 312         iounmap(ramips_wdt_base);
 313         return err;
 314 }
 315
 316 static int ramips_wdt_remove(struct platform_device *pdev)
 317 {
 318         misc_deregister(&ramips_wdt_miscdev);
 319         clk_disable(ramips_wdt_clk);
 320         clk_put(ramips_wdt_clk);
 321         iounmap(ramips_wdt_base);
 322         return 0;
 323 }
 324
 325 static void ramips_wdt_shutdown(struct platform_device *pdev)
 326 {
 327         ramips_wdt_disable();
 328 }
 329
 330 static struct platform_driver ramips_wdt_driver = {
 331         .remove         = ramips_wdt_remove,
 332         .shutdown       = ramips_wdt_shutdown,
 333         .driver         = {
 334                 .name   = DRIVER_NAME,
 335                 .owner  = THIS_MODULE,
 336         },
 337 };
 338
 339 static int __init ramips_wdt_init(void)
 340 {
 341         return platform_driver_probe(&ramips_wdt_driver, ramips_wdt_probe);
 342 }
 343 module_init(ramips_wdt_init);
 344
 345 static void __exit ramips_wdt_exit(void)
 346 {
 347         platform_driver_unregister(&ramips_wdt_driver);
 348 }
 349 module_exit(ramips_wdt_exit);
 350
 351 MODULE_DESCRIPTION("Ralink RT288X/RT305X hardware watchdog driver");
 352 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");
 353 MODULE_LICENSE("GPL v2");
 354 MODULE_ALIAS("platform:" DRIVER_NAME);
 355 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);