drivers/watchdog/pnx4008_wdt.c

   1 /*
   2  * drivers/char/watchdog/pnx4008_wdt.c
   3  *
   4  * Watchdog driver for PNX4008 board
   5  *
   6  * Authors: Dmitry Chigirev <source@mvista.com>,
   7  *          Vitaly Wool <vitalywool@gmail.com>
   8  * Based on sa1100 driver,
   9  * Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
  10  *
  11  * 2005-2006 (c) MontaVista Software, Inc. This file is licensed under
  12  * the terms of the GNU General Public License version 2. This program
  13  * is licensed "as is" without any warranty of any kind, whether express
  14  * or implied.
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/moduleparam.h>
  19 #include <linux/types.h>
  20 #include <linux/kernel.h>
  21 #include <linux/fs.h>
  22 #include <linux/miscdevice.h>
  23 #include <linux/watchdog.h>
  24 #include <linux/init.h>
  25 #include <linux/bitops.h>
  26 #include <linux/ioport.h>
  27 #include <linux/device.h>
  28 #include <linux/platform_device.h>
  29 #include <linux/clk.h>
  30 #include <linux/spinlock.h>
  31 #include <linux/uaccess.h>
  32 #include <linux/io.h>
  33
  34 #include <asm/hardware.h>
  35
  36 #define MODULE_NAME "PNX4008-WDT: "
  37
  38 /* WatchDog Timer - Chapter 23 Page 207 */
  39
  40 #define DEFAULT_HEARTBEAT 19
  41 #define MAX_HEARTBEAT     60
  42
  43 /* Watchdog timer register set definition */
  44 #define WDTIM_INT(p)     ((p) + 0x0)
  45 #define WDTIM_CTRL(p)    ((p) + 0x4)
  46 #define WDTIM_COUNTER(p) ((p) + 0x8)
  47 #define WDTIM_MCTRL(p)   ((p) + 0xC)
  48 #define WDTIM_MATCH0(p)  ((p) + 0x10)
  49 #define WDTIM_EMR(p)     ((p) + 0x14)
  50 #define WDTIM_PULSE(p)   ((p) + 0x18)
  51 #define WDTIM_RES(p)     ((p) + 0x1C)
  52
  53 /* WDTIM_INT bit definitions */
  54 #define MATCH_INT      1
  55
  56 /* WDTIM_CTRL bit definitions */
  57 #define COUNT_ENAB     1
  58 #define RESET_COUNT    (1<<1)
  59 #define DEBUG_EN       (1<<2)
  60
  61 /* WDTIM_MCTRL bit definitions */
  62 #define MR0_INT        1
  63 #undef  RESET_COUNT0
  64 #define RESET_COUNT0   (1<<2)
  65 #define STOP_COUNT0    (1<<2)
  66 #define M_RES1         (1<<3)
  67 #define M_RES2         (1<<4)
  68 #define RESFRC1        (1<<5)
  69 #define RESFRC2        (1<<6)
  70
  71 /* WDTIM_EMR bit definitions */
  72 #define EXT_MATCH0      1
  73 #define MATCH_OUTPUT_HIGH (2<<4)        /*a MATCH_CTRL setting */
  74
  75 /* WDTIM_RES bit definitions */
  76 #define WDOG_RESET      1       /* read only */
  77
  78 #define WDOG_COUNTER_RATE 13000000      /*the counter clock is 13 MHz fixed */
  79
  80 static int nowayout = WATCHDOG_NOWAYOUT;
  81 static int heartbeat = DEFAULT_HEARTBEAT;
  82
  83 static DEFINE_SPINLOCK(io_lock);
  84 static unsigned long wdt_status;
  85 #define WDT_IN_USE        0
  86 #define WDT_OK_TO_CLOSE   1
  87 #define WDT_REGION_INITED 2
  88 #define WDT_DEVICE_INITED 3
  89
  90 static unsigned long boot_status;
  91
  92 static struct resource  *wdt_mem;
  93 static void __iomem     *wdt_base;
  94 struct clk              *wdt_clk;
  95
  96 static void wdt_enable(void)
  97 {
  98         spin_lock(&io_lock);
  99
 100         if (wdt_clk)
 101                 clk_set_rate(wdt_clk, 1);
 102
 103         /* stop counter, initiate counter reset */
 104         __raw_writel(RESET_COUNT, WDTIM_CTRL(wdt_base));
 105         /*wait for reset to complete. 100% guarantee event */
 106         while (__raw_readl(WDTIM_COUNTER(wdt_base)))
 107                 cpu_relax();
 108         /* internal and external reset, stop after that */
 109         __raw_writel(M_RES2 | STOP_COUNT0 | RESET_COUNT0,
 110                 WDTIM_MCTRL(wdt_base));
 111         /* configure match output */
 112         __raw_writel(MATCH_OUTPUT_HIGH, WDTIM_EMR(wdt_base));
 113         /* clear interrupt, just in case */
 114         __raw_writel(MATCH_INT, WDTIM_INT(wdt_base));
 115         /* the longest pulse period 65541/(13*10^6) seconds ~ 5 ms. */
 116         __raw_writel(0xFFFF, WDTIM_PULSE(wdt_base));
 117         __raw_writel(heartbeat * WDOG_COUNTER_RATE, WDTIM_MATCH0(wdt_base));
 118         /*enable counter, stop when debugger active */
 119         __raw_writel(COUNT_ENAB | DEBUG_EN, WDTIM_CTRL(wdt_base));
 120
 121         spin_unlock(&io_lock);
 122 }
 123
 124 static void wdt_disable(void)
 125 {
 126         spin_lock(&io_lock);
 127
 128         __raw_writel(0, WDTIM_CTRL(wdt_base));  /*stop counter */
 129         if (wdt_clk)
 130                 clk_set_rate(wdt_clk, 0);
 131
 132         spin_unlock(&io_lock);
 133 }
 134
 135 static int pnx4008_wdt_open(struct inode *inode, struct file *file)
 136 {
 137         if (test_and_set_bit(WDT_IN_USE, &wdt_status))
 138                 return -EBUSY;
 139
 140         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 141
 142         wdt_enable();
 143
 144         return nonseekable_open(inode, file);
 145 }
 146
 147 static ssize_t pnx4008_wdt_write(struct file *file, const char *data,
 148                                         size_t len, loff_t *ppos)
 149 {
 150         if (len) {
 151                 if (!nowayout) {
 152                         size_t i;
 153
 154                         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 155
 156                         for (i = 0; i != len; i++) {
 157                                 char c;
 158
 159                                 if (get_user(c, data + i))
 160                                         return -EFAULT;
 161                                 if (c == 'V')
 162                                         set_bit(WDT_OK_TO_CLOSE, &wdt_status);
 163                         }
 164                 }
 165                 wdt_enable();
 166         }
 167
 168         return len;
 169 }
 170
 171 static const struct watchdog_info ident = {
 172         .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
 173             WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 174         .identity = "PNX4008 Watchdog",
 175 };
 176
 177 static long pnx4008_wdt_ioctl(struct inode *inode, struct file *file,
 178                                         unsigned int cmd, unsigned long arg)
 179 {
 180         int ret = -ENOTTY;
 181         int time;
 182
 183         switch (cmd) {
 184         case WDIOC_GETSUPPORT:
 185                 ret = copy_to_user((struct watchdog_info *)arg, &ident,
 186                                    sizeof(ident)) ? -EFAULT : 0;
 187                 break;
 188
 189         case WDIOC_GETSTATUS:
 190                 ret = put_user(0, (int *)arg);
 191                 break;
 192
 193         case WDIOC_GETBOOTSTATUS:
 194                 ret = put_user(boot_status, (int *)arg);
 195                 break;
 196
 197         case WDIOC_KEEPALIVE:
 198                 wdt_enable();
 199                 ret = 0;
 200                 break;
 201
 202         case WDIOC_SETTIMEOUT:
 203                 ret = get_user(time, (int *)arg);
 204                 if (ret)
 205                         break;
 206
 207                 if (time <= 0 || time > MAX_HEARTBEAT) {
 208                         ret = -EINVAL;
 209                         break;
 210                 }
 211
 212                 heartbeat = time;
 213                 wdt_enable();
 214                 /* Fall through */
 215
 216         case WDIOC_GETTIMEOUT:
 217                 ret = put_user(heartbeat, (int *)arg);
 218                 break;
 219         }
 220         return ret;
 221 }
 222
 223 static int pnx4008_wdt_release(struct inode *inode, struct file *file)
 224 {
 225         if (!test_bit(WDT_OK_TO_CLOSE, &wdt_status))
 226                 printk(KERN_WARNING "WATCHDOG: Device closed unexpectdly\n");
 227
 228         wdt_disable();
 229         clear_bit(WDT_IN_USE, &wdt_status);
 230         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 231
 232         return 0;
 233 }
 234
 235 static const struct file_operations pnx4008_wdt_fops = {
 236         .owner = THIS_MODULE,
 237         .llseek = no_llseek,
 238         .write = pnx4008_wdt_write,
 239         .unlocked_ioctl = pnx4008_wdt_ioctl,
 240         .open = pnx4008_wdt_open,
 241         .release = pnx4008_wdt_release,
 242 };
 243
 244 static struct miscdevice pnx4008_wdt_miscdev = {
 245         .minor = WATCHDOG_MINOR,
 246         .name = "watchdog",
 247         .fops = &pnx4008_wdt_fops,
 248 };
 249
 250 static int pnx4008_wdt_probe(struct platform_device *pdev)
 251 {
 252         int ret = 0, size;
 253         struct resource *res;
 254
 255         if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
 256                 heartbeat = DEFAULT_HEARTBEAT;
 257
 258         printk(KERN_INFO MODULE_NAME
 259                 "PNX4008 Watchdog Timer: heartbeat %d sec\n", heartbeat);
 260
 261         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 262         if (res == NULL) {
 263                 printk(KERN_INFO MODULE_NAME
 264                         "failed to get memory region resouce\n");
 265                 return -ENOENT;
 266         }
 267
 268         size = res->end - res->start + 1;
 269         wdt_mem = request_mem_region(res->start, size, pdev->name);
 270
 271         if (wdt_mem == NULL) {
 272                 printk(KERN_INFO MODULE_NAME "failed to get memory region\n");
 273                 return -ENOENT;
 274         }
 275         wdt_base = (void __iomem *)IO_ADDRESS(res->start);
 276
 277         wdt_clk = clk_get(&pdev->dev, "wdt_ck");
 278         if (IS_ERR(wdt_clk)) {
 279                 ret = PTR_ERR(wdt_clk);
 280                 release_resource(wdt_mem);
 281                 kfree(wdt_mem);
 282                 goto out;
 283         } else
 284                 clk_set_rate(wdt_clk, 1);
 285
 286         ret = misc_register(&pnx4008_wdt_miscdev);
 287         if (ret < 0) {
 288                 printk(KERN_ERR MODULE_NAME "cannot register misc device\n");
 289                 release_resource(wdt_mem);
 290                 kfree(wdt_mem);
 291                 clk_set_rate(wdt_clk, 0);
 292         } else {
 293                 boot_status = (__raw_readl(WDTIM_RES(wdt_base)) & WDOG_RESET) ?
 294                     WDIOF_CARDRESET : 0;
 295                 wdt_disable();          /*disable for now */
 296                 set_bit(WDT_DEVICE_INITED, &wdt_status);
 297         }
 298
 299 out:
 300         return ret;
 301 }
 302
 303 static int pnx4008_wdt_remove(struct platform_device *pdev)
 304 {
 305         misc_deregister(&pnx4008_wdt_miscdev);
 306         if (wdt_clk) {
 307                 clk_set_rate(wdt_clk, 0);
 308                 clk_put(wdt_clk);
 309                 wdt_clk = NULL;
 310         }
 311         if (wdt_mem) {
 312                 release_resource(wdt_mem);
 313                 kfree(wdt_mem);
 314                 wdt_mem = NULL;
 315         }
 316         return 0;
 317 }
 318
 319 static struct platform_driver platform_wdt_driver = {
 320         .driver = {
 321                 .name = "watchdog",
 322                 .owner  = THIS_MODULE,
 323         },
 324         .probe = pnx4008_wdt_probe,
 325         .remove = pnx4008_wdt_remove,
 326 };
 327
 328 static int __init pnx4008_wdt_init(void)
 329 {
 330         return platform_driver_register(&platform_wdt_driver);
 331 }
 332
 333 static void __exit pnx4008_wdt_exit(void)
 334 {
 335         platform_driver_unregister(&platform_wdt_driver);
 336 }
 337
 338 module_init(pnx4008_wdt_init);
 339 module_exit(pnx4008_wdt_exit);
 340
 341 MODULE_AUTHOR("MontaVista Software, Inc. <source@mvista.com>");
 342 MODULE_DESCRIPTION("PNX4008 Watchdog Driver");
 343
 344 module_param(heartbeat, int, 0);
 345 MODULE_PARM_DESC(heartbeat,
 346                  "Watchdog heartbeat period in seconds from 1 to "
 347                  __MODULE_STRING(MAX_HEARTBEAT) ", default "
 348                  __MODULE_STRING(DEFAULT_HEARTBEAT));
 349
 350 module_param(nowayout, int, 0);
 351 MODULE_PARM_DESC(nowayout,
 352                  "Set to 1 to keep watchdog running after device release");
 353
 354 MODULE_LICENSE("GPL");
 355 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 356 MODULE_ALIAS("platform:watchdog");