sa1100_wdt.c 4.9 KB

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  1. // SPDX-License-Identifier: GPL-2.0+
  2. /*
  3. * Watchdog driver for the SA11x0/PXA2xx
  4. *
  5. * (c) Copyright 2000 Oleg Drokin <green@crimea.edu>
  6. * Based on SoftDog driver by Alan Cox <alan@lxorguk.ukuu.org.uk>
  7. *
  8. * Neither Oleg Drokin nor iXcelerator.com admit liability nor provide
  9. * warranty for any of this software. This material is provided
  10. * "AS-IS" and at no charge.
  11. *
  12. * (c) Copyright 2000 Oleg Drokin <green@crimea.edu>
  13. *
  14. * 27/11/2000 Initial release
  15. */
  16. #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  17. #include <linux/module.h>
  18. #include <linux/moduleparam.h>
  19. #include <linux/clk.h>
  20. #include <linux/types.h>
  21. #include <linux/kernel.h>
  22. #include <linux/fs.h>
  23. #include <linux/miscdevice.h>
  24. #include <linux/watchdog.h>
  25. #include <linux/init.h>
  26. #include <linux/io.h>
  27. #include <linux/bitops.h>
  28. #include <linux/uaccess.h>
  29. #include <linux/timex.h>
  30. #ifdef CONFIG_ARCH_PXA
  31. #include <mach/regs-ost.h>
  32. #endif
  33. #include <mach/reset.h>
  34. #include <mach/hardware.h>
  35. static unsigned long oscr_freq;
  36. static unsigned long sa1100wdt_users;
  37. static unsigned int pre_margin;
  38. static int boot_status;
  39. /*
  40. * Allow only one person to hold it open
  41. */
  42. static int sa1100dog_open(struct inode *inode, struct file *file)
  43. {
  44. if (test_and_set_bit(1, &sa1100wdt_users))
  45. return -EBUSY;
  46. /* Activate SA1100 Watchdog timer */
  47. writel_relaxed(readl_relaxed(OSCR) + pre_margin, OSMR3);
  48. writel_relaxed(OSSR_M3, OSSR);
  49. writel_relaxed(OWER_WME, OWER);
  50. writel_relaxed(readl_relaxed(OIER) | OIER_E3, OIER);
  51. return stream_open(inode, file);
  52. }
  53. /*
  54. * The watchdog cannot be disabled.
  55. *
  56. * Previous comments suggested that turning off the interrupt by
  57. * clearing OIER[E3] would prevent the watchdog timing out but this
  58. * does not appear to be true (at least on the PXA255).
  59. */
  60. static int sa1100dog_release(struct inode *inode, struct file *file)
  61. {
  62. pr_crit("Device closed - timer will not stop\n");
  63. clear_bit(1, &sa1100wdt_users);
  64. return 0;
  65. }
  66. static ssize_t sa1100dog_write(struct file *file, const char __user *data,
  67. size_t len, loff_t *ppos)
  68. {
  69. if (len)
  70. /* Refresh OSMR3 timer. */
  71. writel_relaxed(readl_relaxed(OSCR) + pre_margin, OSMR3);
  72. return len;
  73. }
  74. static const struct watchdog_info ident = {
  75. .options = WDIOF_CARDRESET | WDIOF_SETTIMEOUT
  76. | WDIOF_KEEPALIVEPING,
  77. .identity = "SA1100/PXA255 Watchdog",
  78. .firmware_version = 1,
  79. };
  80. static long sa1100dog_ioctl(struct file *file, unsigned int cmd,
  81. unsigned long arg)
  82. {
  83. int ret = -ENOTTY;
  84. int time;
  85. void __user *argp = (void __user *)arg;
  86. int __user *p = argp;
  87. switch (cmd) {
  88. case WDIOC_GETSUPPORT:
  89. ret = copy_to_user(argp, &ident,
  90. sizeof(ident)) ? -EFAULT : 0;
  91. break;
  92. case WDIOC_GETSTATUS:
  93. ret = put_user(0, p);
  94. break;
  95. case WDIOC_GETBOOTSTATUS:
  96. ret = put_user(boot_status, p);
  97. break;
  98. case WDIOC_KEEPALIVE:
  99. writel_relaxed(readl_relaxed(OSCR) + pre_margin, OSMR3);
  100. ret = 0;
  101. break;
  102. case WDIOC_SETTIMEOUT:
  103. ret = get_user(time, p);
  104. if (ret)
  105. break;
  106. if (time <= 0 || (oscr_freq * (long long)time >= 0xffffffff)) {
  107. ret = -EINVAL;
  108. break;
  109. }
  110. pre_margin = oscr_freq * time;
  111. writel_relaxed(readl_relaxed(OSCR) + pre_margin, OSMR3);
  112. fallthrough;
  113. case WDIOC_GETTIMEOUT:
  114. ret = put_user(pre_margin / oscr_freq, p);
  115. break;
  116. }
  117. return ret;
  118. }
  119. static const struct file_operations sa1100dog_fops = {
  120. .owner = THIS_MODULE,
  121. .llseek = no_llseek,
  122. .write = sa1100dog_write,
  123. .unlocked_ioctl = sa1100dog_ioctl,
  124. .compat_ioctl = compat_ptr_ioctl,
  125. .open = sa1100dog_open,
  126. .release = sa1100dog_release,
  127. };
  128. static struct miscdevice sa1100dog_miscdev = {
  129. .minor = WATCHDOG_MINOR,
  130. .name = "watchdog",
  131. .fops = &sa1100dog_fops,
  132. };
  133. static int margin __initdata = 60; /* (secs) Default is 1 minute */
  134. static struct clk *clk;
  135. static int __init sa1100dog_init(void)
  136. {
  137. int ret;
  138. clk = clk_get(NULL, "OSTIMER0");
  139. if (IS_ERR(clk)) {
  140. pr_err("SA1100/PXA2xx Watchdog Timer: clock not found: %d\n",
  141. (int) PTR_ERR(clk));
  142. return PTR_ERR(clk);
  143. }
  144. ret = clk_prepare_enable(clk);
  145. if (ret) {
  146. pr_err("SA1100/PXA2xx Watchdog Timer: clock failed to prepare+enable: %d\n",
  147. ret);
  148. goto err;
  149. }
  150. oscr_freq = clk_get_rate(clk);
  151. /*
  152. * Read the reset status, and save it for later. If
  153. * we suspend, RCSR will be cleared, and the watchdog
  154. * reset reason will be lost.
  155. */
  156. boot_status = (reset_status & RESET_STATUS_WATCHDOG) ?
  157. WDIOF_CARDRESET : 0;
  158. pre_margin = oscr_freq * margin;
  159. ret = misc_register(&sa1100dog_miscdev);
  160. if (ret == 0) {
  161. pr_info("SA1100/PXA2xx Watchdog Timer: timer margin %d sec\n",
  162. margin);
  163. return 0;
  164. }
  165. clk_disable_unprepare(clk);
  166. err:
  167. clk_put(clk);
  168. return ret;
  169. }
  170. static void __exit sa1100dog_exit(void)
  171. {
  172. misc_deregister(&sa1100dog_miscdev);
  173. clk_disable_unprepare(clk);
  174. clk_put(clk);
  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_LICENSE("GPL");