stm32_hwspinlock.c 3.8 KB

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  1. // SPDX-License-Identifier: GPL-2.0
  2. /*
  3. * Copyright (C) STMicroelectronics SA 2018
  4. * Author: Benjamin Gaignard <benjamin.gaignard@st.com> for STMicroelectronics.
  5. */
  6. #include <linux/clk.h>
  7. #include <linux/delay.h>
  8. #include <linux/hwspinlock.h>
  9. #include <linux/io.h>
  10. #include <linux/kernel.h>
  11. #include <linux/module.h>
  12. #include <linux/of.h>
  13. #include <linux/platform_device.h>
  14. #include <linux/pm_runtime.h>
  15. #include "hwspinlock_internal.h"
  16. #define STM32_MUTEX_COREID BIT(8)
  17. #define STM32_MUTEX_LOCK_BIT BIT(31)
  18. #define STM32_MUTEX_NUM_LOCKS 32
  19. struct stm32_hwspinlock {
  20. struct clk *clk;
  21. struct hwspinlock_device bank;
  22. };
  23. static int stm32_hwspinlock_trylock(struct hwspinlock *lock)
  24. {
  25. void __iomem *lock_addr = lock->priv;
  26. u32 status;
  27. writel(STM32_MUTEX_LOCK_BIT | STM32_MUTEX_COREID, lock_addr);
  28. status = readl(lock_addr);
  29. return status == (STM32_MUTEX_LOCK_BIT | STM32_MUTEX_COREID);
  30. }
  31. static void stm32_hwspinlock_unlock(struct hwspinlock *lock)
  32. {
  33. void __iomem *lock_addr = lock->priv;
  34. writel(STM32_MUTEX_COREID, lock_addr);
  35. }
  36. static void stm32_hwspinlock_relax(struct hwspinlock *lock)
  37. {
  38. ndelay(50);
  39. }
  40. static const struct hwspinlock_ops stm32_hwspinlock_ops = {
  41. .trylock = stm32_hwspinlock_trylock,
  42. .unlock = stm32_hwspinlock_unlock,
  43. .relax = stm32_hwspinlock_relax,
  44. };
  45. static int stm32_hwspinlock_probe(struct platform_device *pdev)
  46. {
  47. struct stm32_hwspinlock *hw;
  48. void __iomem *io_base;
  49. size_t array_size;
  50. int i, ret;
  51. io_base = devm_platform_ioremap_resource(pdev, 0);
  52. if (IS_ERR(io_base))
  53. return PTR_ERR(io_base);
  54. array_size = STM32_MUTEX_NUM_LOCKS * sizeof(struct hwspinlock);
  55. hw = devm_kzalloc(&pdev->dev, sizeof(*hw) + array_size, GFP_KERNEL);
  56. if (!hw)
  57. return -ENOMEM;
  58. hw->clk = devm_clk_get(&pdev->dev, "hsem");
  59. if (IS_ERR(hw->clk))
  60. return PTR_ERR(hw->clk);
  61. for (i = 0; i < STM32_MUTEX_NUM_LOCKS; i++)
  62. hw->bank.lock[i].priv = io_base + i * sizeof(u32);
  63. platform_set_drvdata(pdev, hw);
  64. pm_runtime_enable(&pdev->dev);
  65. ret = hwspin_lock_register(&hw->bank, &pdev->dev, &stm32_hwspinlock_ops,
  66. 0, STM32_MUTEX_NUM_LOCKS);
  67. if (ret)
  68. pm_runtime_disable(&pdev->dev);
  69. return ret;
  70. }
  71. static int stm32_hwspinlock_remove(struct platform_device *pdev)
  72. {
  73. struct stm32_hwspinlock *hw = platform_get_drvdata(pdev);
  74. int ret;
  75. ret = hwspin_lock_unregister(&hw->bank);
  76. if (ret)
  77. dev_err(&pdev->dev, "%s failed: %d\n", __func__, ret);
  78. pm_runtime_disable(&pdev->dev);
  79. return 0;
  80. }
  81. static int __maybe_unused stm32_hwspinlock_runtime_suspend(struct device *dev)
  82. {
  83. struct stm32_hwspinlock *hw = dev_get_drvdata(dev);
  84. clk_disable_unprepare(hw->clk);
  85. return 0;
  86. }
  87. static int __maybe_unused stm32_hwspinlock_runtime_resume(struct device *dev)
  88. {
  89. struct stm32_hwspinlock *hw = dev_get_drvdata(dev);
  90. clk_prepare_enable(hw->clk);
  91. return 0;
  92. }
  93. static const struct dev_pm_ops stm32_hwspinlock_pm_ops = {
  94. SET_RUNTIME_PM_OPS(stm32_hwspinlock_runtime_suspend,
  95. stm32_hwspinlock_runtime_resume,
  96. NULL)
  97. };
  98. static const struct of_device_id stm32_hwpinlock_ids[] = {
  99. { .compatible = "st,stm32-hwspinlock", },
  100. {},
  101. };
  102. MODULE_DEVICE_TABLE(of, stm32_hwpinlock_ids);
  103. static struct platform_driver stm32_hwspinlock_driver = {
  104. .probe = stm32_hwspinlock_probe,
  105. .remove = stm32_hwspinlock_remove,
  106. .driver = {
  107. .name = "stm32_hwspinlock",
  108. .of_match_table = stm32_hwpinlock_ids,
  109. .pm = &stm32_hwspinlock_pm_ops,
  110. },
  111. };
  112. static int __init stm32_hwspinlock_init(void)
  113. {
  114. return platform_driver_register(&stm32_hwspinlock_driver);
  115. }
  116. /* board init code might need to reserve hwspinlocks for predefined purposes */
  117. postcore_initcall(stm32_hwspinlock_init);
  118. static void __exit stm32_hwspinlock_exit(void)
  119. {
  120. platform_driver_unregister(&stm32_hwspinlock_driver);
  121. }
  122. module_exit(stm32_hwspinlock_exit);
  123. MODULE_LICENSE("GPL v2");
  124. MODULE_DESCRIPTION("Hardware spinlock driver for STM32 SoCs");
  125. MODULE_AUTHOR("Benjamin Gaignard <benjamin.gaignard@st.com>");