retu_wdt.c 4.1 KB

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  1. // SPDX-License-Identifier: GPL-2.0+
  2. /*
  3. * Retu watchdog driver
  4. *
  5. * Copyright (C) 2004, 2005 Nokia Corporation
  6. *
  7. * Based on code written by Amit Kucheria and Michael Buesch.
  8. * Rewritten by Aaro Koskinen.
  9. */
  10. #include <linux/slab.h>
  11. #include <linux/errno.h>
  12. #include <linux/device.h>
  13. #include <linux/kernel.h>
  14. #include <linux/module.h>
  15. #include <linux/mfd/retu.h>
  16. #include <linux/watchdog.h>
  17. #include <linux/platform_device.h>
  18. /* Watchdog timer values in seconds */
  19. #define RETU_WDT_MAX_TIMER 63
  20. struct retu_wdt_dev {
  21. struct retu_dev *rdev;
  22. struct device *dev;
  23. struct delayed_work ping_work;
  24. };
  25. /*
  26. * Since Retu watchdog cannot be disabled in hardware, we must kick it
  27. * with a timer until userspace watchdog software takes over. If
  28. * CONFIG_WATCHDOG_NOWAYOUT is set, we never start the feeding.
  29. */
  30. static void retu_wdt_ping_enable(struct retu_wdt_dev *wdev)
  31. {
  32. retu_write(wdev->rdev, RETU_REG_WATCHDOG, RETU_WDT_MAX_TIMER);
  33. schedule_delayed_work(&wdev->ping_work,
  34. round_jiffies_relative(RETU_WDT_MAX_TIMER * HZ / 2));
  35. }
  36. static void retu_wdt_ping_disable(struct retu_wdt_dev *wdev)
  37. {
  38. retu_write(wdev->rdev, RETU_REG_WATCHDOG, RETU_WDT_MAX_TIMER);
  39. cancel_delayed_work_sync(&wdev->ping_work);
  40. }
  41. static void retu_wdt_ping_work(struct work_struct *work)
  42. {
  43. struct retu_wdt_dev *wdev = container_of(to_delayed_work(work),
  44. struct retu_wdt_dev, ping_work);
  45. retu_wdt_ping_enable(wdev);
  46. }
  47. static int retu_wdt_start(struct watchdog_device *wdog)
  48. {
  49. struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
  50. retu_wdt_ping_disable(wdev);
  51. return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
  52. }
  53. static int retu_wdt_stop(struct watchdog_device *wdog)
  54. {
  55. struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
  56. retu_wdt_ping_enable(wdev);
  57. return 0;
  58. }
  59. static int retu_wdt_ping(struct watchdog_device *wdog)
  60. {
  61. struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
  62. return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
  63. }
  64. static int retu_wdt_set_timeout(struct watchdog_device *wdog,
  65. unsigned int timeout)
  66. {
  67. struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
  68. wdog->timeout = timeout;
  69. return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
  70. }
  71. static const struct watchdog_info retu_wdt_info = {
  72. .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
  73. .identity = "Retu watchdog",
  74. };
  75. static const struct watchdog_ops retu_wdt_ops = {
  76. .owner = THIS_MODULE,
  77. .start = retu_wdt_start,
  78. .stop = retu_wdt_stop,
  79. .ping = retu_wdt_ping,
  80. .set_timeout = retu_wdt_set_timeout,
  81. };
  82. static int retu_wdt_probe(struct platform_device *pdev)
  83. {
  84. struct retu_dev *rdev = dev_get_drvdata(pdev->dev.parent);
  85. bool nowayout = WATCHDOG_NOWAYOUT;
  86. struct watchdog_device *retu_wdt;
  87. struct retu_wdt_dev *wdev;
  88. int ret;
  89. retu_wdt = devm_kzalloc(&pdev->dev, sizeof(*retu_wdt), GFP_KERNEL);
  90. if (!retu_wdt)
  91. return -ENOMEM;
  92. wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL);
  93. if (!wdev)
  94. return -ENOMEM;
  95. retu_wdt->info = &retu_wdt_info;
  96. retu_wdt->ops = &retu_wdt_ops;
  97. retu_wdt->timeout = RETU_WDT_MAX_TIMER;
  98. retu_wdt->min_timeout = 0;
  99. retu_wdt->max_timeout = RETU_WDT_MAX_TIMER;
  100. retu_wdt->parent = &pdev->dev;
  101. watchdog_set_drvdata(retu_wdt, wdev);
  102. watchdog_set_nowayout(retu_wdt, nowayout);
  103. wdev->rdev = rdev;
  104. wdev->dev = &pdev->dev;
  105. INIT_DELAYED_WORK(&wdev->ping_work, retu_wdt_ping_work);
  106. ret = watchdog_register_device(retu_wdt);
  107. if (ret < 0)
  108. return ret;
  109. if (nowayout)
  110. retu_wdt_ping(retu_wdt);
  111. else
  112. retu_wdt_ping_enable(wdev);
  113. platform_set_drvdata(pdev, retu_wdt);
  114. return 0;
  115. }
  116. static int retu_wdt_remove(struct platform_device *pdev)
  117. {
  118. struct watchdog_device *wdog = platform_get_drvdata(pdev);
  119. struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
  120. watchdog_unregister_device(wdog);
  121. cancel_delayed_work_sync(&wdev->ping_work);
  122. return 0;
  123. }
  124. static struct platform_driver retu_wdt_driver = {
  125. .probe = retu_wdt_probe,
  126. .remove = retu_wdt_remove,
  127. .driver = {
  128. .name = "retu-wdt",
  129. },
  130. };
  131. module_platform_driver(retu_wdt_driver);
  132. MODULE_ALIAS("platform:retu-wdt");
  133. MODULE_DESCRIPTION("Retu watchdog");
  134. MODULE_AUTHOR("Amit Kucheria");
  135. MODULE_AUTHOR("Aaro Koskinen <aaro.koskinen@iki.fi>");
  136. MODULE_LICENSE("GPL");