/drivers/char/watchdog/sa1100_wdt.c

https://bitbucket.org/evzijst/gittest · C · 223 lines · 149 code · 38 blank · 36 comment · 17 complexity · b849a2655c8b5cdcb7cc751e2703cd79 MD5 · raw file

  1. /*
  2. * Watchdog driver for the SA11x0/PXA2xx
  3. *
  4. * (c) Copyright 2000 Oleg Drokin <green@crimea.edu>
  5. * Based on SoftDog driver by Alan Cox <alan@redhat.com>
  6. *
  7. * This program is free software; you can redistribute it and/or
  8. * modify it under the terms of the GNU General Public License
  9. * as published by the Free Software Foundation; either version
  10. * 2 of the License, or (at your option) any later version.
  11. *
  12. * Neither Oleg Drokin nor iXcelerator.com admit liability nor provide
  13. * warranty for any of this software. This material is provided
  14. * "AS-IS" and at no charge.
  15. *
  16. * (c) Copyright 2000 Oleg Drokin <green@crimea.edu>
  17. *
  18. * 27/11/2000 Initial release
  19. */
  20. #include <linux/config.h>
  21. #include <linux/module.h>
  22. #include <linux/moduleparam.h>
  23. #include <linux/types.h>
  24. #include <linux/kernel.h>
  25. #include <linux/fs.h>
  26. #include <linux/miscdevice.h>
  27. #include <linux/watchdog.h>
  28. #include <linux/init.h>
  29. #ifdef CONFIG_ARCH_PXA
  30. #include <asm/arch/pxa-regs.h>
  31. #endif
  32. #include <asm/hardware.h>
  33. #include <asm/bitops.h>
  34. #include <asm/uaccess.h>
  35. #define OSCR_FREQ CLOCK_TICK_RATE
  36. #define SA1100_CLOSE_MAGIC (0x5afc4453)
  37. static unsigned long sa1100wdt_users;
  38. static int expect_close;
  39. static int pre_margin;
  40. static int boot_status;
  41. #ifdef CONFIG_WATCHDOG_NOWAYOUT
  42. static int nowayout = 1;
  43. #else
  44. static int nowayout = 0;
  45. #endif
  46. /*
  47. * Allow only one person to hold it open
  48. */
  49. static int sa1100dog_open(struct inode *inode, struct file *file)
  50. {
  51. nonseekable_open(inode, file);
  52. if (test_and_set_bit(1,&sa1100wdt_users))
  53. return -EBUSY;
  54. /* Activate SA1100 Watchdog timer */
  55. OSMR3 = OSCR + pre_margin;
  56. OSSR = OSSR_M3;
  57. OWER = OWER_WME;
  58. OIER |= OIER_E3;
  59. return 0;
  60. }
  61. /*
  62. * Shut off the timer.
  63. * Lock it in if it's a module and we defined ...NOWAYOUT
  64. * Oddly, the watchdog can only be enabled, but we can turn off
  65. * the interrupt, which appears to prevent the watchdog timing out.
  66. */
  67. static int sa1100dog_release(struct inode *inode, struct file *file)
  68. {
  69. OSMR3 = OSCR + pre_margin;
  70. if (expect_close == SA1100_CLOSE_MAGIC) {
  71. OIER &= ~OIER_E3;
  72. } else {
  73. printk(KERN_CRIT "WATCHDOG: WDT device closed unexpectedly. WDT will not stop!\n");
  74. }
  75. clear_bit(1, &sa1100wdt_users);
  76. expect_close = 0;
  77. return 0;
  78. }
  79. static ssize_t sa1100dog_write(struct file *file, const char *data, size_t len, loff_t *ppos)
  80. {
  81. if (len) {
  82. if (!nowayout) {
  83. size_t i;
  84. expect_close = 0;
  85. for (i = 0; i != len; i++) {
  86. char c;
  87. if (get_user(c, data + i))
  88. return -EFAULT;
  89. if (c == 'V')
  90. expect_close = SA1100_CLOSE_MAGIC;
  91. }
  92. }
  93. /* Refresh OSMR3 timer. */
  94. OSMR3 = OSCR + pre_margin;
  95. }
  96. return len;
  97. }
  98. static struct watchdog_info ident = {
  99. .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
  100. WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
  101. .identity = "SA1100 Watchdog",
  102. };
  103. static int sa1100dog_ioctl(struct inode *inode, struct file *file,
  104. unsigned int cmd, unsigned long arg)
  105. {
  106. int ret = -ENOIOCTLCMD;
  107. int time;
  108. switch (cmd) {
  109. case WDIOC_GETSUPPORT:
  110. ret = copy_to_user((struct watchdog_info *)arg, &ident,
  111. sizeof(ident)) ? -EFAULT : 0;
  112. break;
  113. case WDIOC_GETSTATUS:
  114. ret = put_user(0, (int *)arg);
  115. break;
  116. case WDIOC_GETBOOTSTATUS:
  117. ret = put_user(boot_status, (int *)arg);
  118. break;
  119. case WDIOC_SETTIMEOUT:
  120. ret = get_user(time, (int *)arg);
  121. if (ret)
  122. break;
  123. if (time <= 0 || time > 255) {
  124. ret = -EINVAL;
  125. break;
  126. }
  127. pre_margin = OSCR_FREQ * time;
  128. OSMR3 = OSCR + pre_margin;
  129. /*fall through*/
  130. case WDIOC_GETTIMEOUT:
  131. ret = put_user(pre_margin / OSCR_FREQ, (int *)arg);
  132. break;
  133. case WDIOC_KEEPALIVE:
  134. OSMR3 = OSCR + pre_margin;
  135. ret = 0;
  136. break;
  137. }
  138. return ret;
  139. }
  140. static struct file_operations sa1100dog_fops =
  141. {
  142. .owner = THIS_MODULE,
  143. .llseek = no_llseek,
  144. .write = sa1100dog_write,
  145. .ioctl = sa1100dog_ioctl,
  146. .open = sa1100dog_open,
  147. .release = sa1100dog_release,
  148. };
  149. static struct miscdevice sa1100dog_miscdev =
  150. {
  151. .minor = WATCHDOG_MINOR,
  152. .name = "SA1100/PXA2xx watchdog",
  153. .fops = &sa1100dog_fops,
  154. };
  155. static int margin __initdata = 60; /* (secs) Default is 1 minute */
  156. static int __init sa1100dog_init(void)
  157. {
  158. int ret;
  159. /*
  160. * Read the reset status, and save it for later. If
  161. * we suspend, RCSR will be cleared, and the watchdog
  162. * reset reason will be lost.
  163. */
  164. boot_status = (RCSR & RCSR_WDR) ? WDIOF_CARDRESET : 0;
  165. pre_margin = OSCR_FREQ * margin;
  166. ret = misc_register(&sa1100dog_miscdev);
  167. if (ret == 0)
  168. printk("SA1100/PXA2xx Watchdog Timer: timer margin %d sec\n",
  169. margin);
  170. return ret;
  171. }
  172. static void __exit sa1100dog_exit(void)
  173. {
  174. misc_deregister(&sa1100dog_miscdev);
  175. }
  176. module_init(sa1100dog_init);
  177. module_exit(sa1100dog_exit);
  178. MODULE_AUTHOR("Oleg Drokin <green@crimea.edu>");
  179. MODULE_DESCRIPTION("SA1100/PXA2xx Watchdog");
  180. module_param(margin, int, 0);
  181. MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)");
  182. module_param(nowayout, int, 0);
  183. MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
  184. MODULE_LICENSE("GPL");
  185. MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);