reset-brcmstb.c 3.3 KB

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  1. // SPDX-License-Identifier: GPL-2.0
  2. /*
  3. * Broadcom STB generic reset controller for SW_INIT style reset controller
  4. *
  5. * Author: Florian Fainelli <f.fainelli@gmail.com>
  6. * Copyright (C) 2018 Broadcom
  7. */
  8. #include <linux/delay.h>
  9. #include <linux/device.h>
  10. #include <linux/io.h>
  11. #include <linux/module.h>
  12. #include <linux/of.h>
  13. #include <linux/platform_device.h>
  14. #include <linux/reset-controller.h>
  15. #include <linux/types.h>
  16. struct brcmstb_reset {
  17. void __iomem *base;
  18. struct reset_controller_dev rcdev;
  19. };
  20. #define SW_INIT_SET 0x00
  21. #define SW_INIT_CLEAR 0x04
  22. #define SW_INIT_STATUS 0x08
  23. #define SW_INIT_BIT(id) BIT((id) & 0x1f)
  24. #define SW_INIT_BANK(id) ((id) >> 5)
  25. /* A full bank contains extra registers that we are not utilizing but still
  26. * qualify as a single bank.
  27. */
  28. #define SW_INIT_BANK_SIZE 0x18
  29. static inline
  30. struct brcmstb_reset *to_brcmstb(struct reset_controller_dev *rcdev)
  31. {
  32. return container_of(rcdev, struct brcmstb_reset, rcdev);
  33. }
  34. static int brcmstb_reset_assert(struct reset_controller_dev *rcdev,
  35. unsigned long id)
  36. {
  37. unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE;
  38. struct brcmstb_reset *priv = to_brcmstb(rcdev);
  39. writel_relaxed(SW_INIT_BIT(id), priv->base + off + SW_INIT_SET);
  40. return 0;
  41. }
  42. static int brcmstb_reset_deassert(struct reset_controller_dev *rcdev,
  43. unsigned long id)
  44. {
  45. unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE;
  46. struct brcmstb_reset *priv = to_brcmstb(rcdev);
  47. writel_relaxed(SW_INIT_BIT(id), priv->base + off + SW_INIT_CLEAR);
  48. /* Maximum reset delay after de-asserting a line and seeing block
  49. * operation is typically 14us for the worst case, build some slack
  50. * here.
  51. */
  52. usleep_range(100, 200);
  53. return 0;
  54. }
  55. static int brcmstb_reset_status(struct reset_controller_dev *rcdev,
  56. unsigned long id)
  57. {
  58. unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE;
  59. struct brcmstb_reset *priv = to_brcmstb(rcdev);
  60. return readl_relaxed(priv->base + off + SW_INIT_STATUS) &
  61. SW_INIT_BIT(id);
  62. }
  63. static const struct reset_control_ops brcmstb_reset_ops = {
  64. .assert = brcmstb_reset_assert,
  65. .deassert = brcmstb_reset_deassert,
  66. .status = brcmstb_reset_status,
  67. };
  68. static int brcmstb_reset_probe(struct platform_device *pdev)
  69. {
  70. struct device *kdev = &pdev->dev;
  71. struct brcmstb_reset *priv;
  72. struct resource *res;
  73. priv = devm_kzalloc(kdev, sizeof(*priv), GFP_KERNEL);
  74. if (!priv)
  75. return -ENOMEM;
  76. res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  77. priv->base = devm_ioremap_resource(kdev, res);
  78. if (IS_ERR(priv->base))
  79. return PTR_ERR(priv->base);
  80. dev_set_drvdata(kdev, priv);
  81. priv->rcdev.owner = THIS_MODULE;
  82. priv->rcdev.nr_resets = DIV_ROUND_DOWN_ULL(resource_size(res),
  83. SW_INIT_BANK_SIZE) * 32;
  84. priv->rcdev.ops = &brcmstb_reset_ops;
  85. priv->rcdev.of_node = kdev->of_node;
  86. /* Use defaults: 1 cell and simple xlate function */
  87. return devm_reset_controller_register(kdev, &priv->rcdev);
  88. }
  89. static const struct of_device_id brcmstb_reset_of_match[] = {
  90. { .compatible = "brcm,brcmstb-reset" },
  91. { /* sentinel */ }
  92. };
  93. MODULE_DEVICE_TABLE(of, brcmstb_reset_of_match);
  94. static struct platform_driver brcmstb_reset_driver = {
  95. .probe = brcmstb_reset_probe,
  96. .driver = {
  97. .name = "brcmstb-reset",
  98. .of_match_table = brcmstb_reset_of_match,
  99. },
  100. };
  101. module_platform_driver(brcmstb_reset_driver);
  102. MODULE_AUTHOR("Broadcom");
  103. MODULE_DESCRIPTION("Broadcom STB reset controller");
  104. MODULE_LICENSE("GPL");