ingenic-trng.c 4.0 KB

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  1. // SPDX-License-Identifier: GPL-2.0
  2. /*
  3. * Ingenic True Random Number Generator driver
  4. * Copyright (c) 2019 漆鹏振 (Qi Pengzhen) <[email protected]>
  5. * Copyright (c) 2020 周琰杰 (Zhou Yanjie) <[email protected]>
  6. */
  7. #include <linux/clk.h>
  8. #include <linux/err.h>
  9. #include <linux/kernel.h>
  10. #include <linux/hw_random.h>
  11. #include <linux/io.h>
  12. #include <linux/iopoll.h>
  13. #include <linux/module.h>
  14. #include <linux/of_device.h>
  15. #include <linux/platform_device.h>
  16. #include <linux/slab.h>
  17. /* DTRNG register offsets */
  18. #define TRNG_REG_CFG_OFFSET 0x00
  19. #define TRNG_REG_RANDOMNUM_OFFSET 0x04
  20. #define TRNG_REG_STATUS_OFFSET 0x08
  21. /* bits within the CFG register */
  22. #define CFG_RDY_CLR BIT(12)
  23. #define CFG_INT_MASK BIT(11)
  24. #define CFG_GEN_EN BIT(0)
  25. /* bits within the STATUS register */
  26. #define STATUS_RANDOM_RDY BIT(0)
  27. struct ingenic_trng {
  28. void __iomem *base;
  29. struct clk *clk;
  30. struct hwrng rng;
  31. };
  32. static int ingenic_trng_init(struct hwrng *rng)
  33. {
  34. struct ingenic_trng *trng = container_of(rng, struct ingenic_trng, rng);
  35. unsigned int ctrl;
  36. ctrl = readl(trng->base + TRNG_REG_CFG_OFFSET);
  37. ctrl |= CFG_GEN_EN;
  38. writel(ctrl, trng->base + TRNG_REG_CFG_OFFSET);
  39. return 0;
  40. }
  41. static void ingenic_trng_cleanup(struct hwrng *rng)
  42. {
  43. struct ingenic_trng *trng = container_of(rng, struct ingenic_trng, rng);
  44. unsigned int ctrl;
  45. ctrl = readl(trng->base + TRNG_REG_CFG_OFFSET);
  46. ctrl &= ~CFG_GEN_EN;
  47. writel(ctrl, trng->base + TRNG_REG_CFG_OFFSET);
  48. }
  49. static int ingenic_trng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
  50. {
  51. struct ingenic_trng *trng = container_of(rng, struct ingenic_trng, rng);
  52. u32 *data = buf;
  53. u32 status;
  54. int ret;
  55. ret = readl_poll_timeout(trng->base + TRNG_REG_STATUS_OFFSET, status,
  56. status & STATUS_RANDOM_RDY, 10, 1000);
  57. if (ret == -ETIMEDOUT) {
  58. pr_err("%s: Wait for DTRNG data ready timeout\n", __func__);
  59. return ret;
  60. }
  61. *data = readl(trng->base + TRNG_REG_RANDOMNUM_OFFSET);
  62. return 4;
  63. }
  64. static int ingenic_trng_probe(struct platform_device *pdev)
  65. {
  66. struct ingenic_trng *trng;
  67. int ret;
  68. trng = devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL);
  69. if (!trng)
  70. return -ENOMEM;
  71. trng->base = devm_platform_ioremap_resource(pdev, 0);
  72. if (IS_ERR(trng->base)) {
  73. pr_err("%s: Failed to map DTRNG registers\n", __func__);
  74. ret = PTR_ERR(trng->base);
  75. return PTR_ERR(trng->base);
  76. }
  77. trng->clk = devm_clk_get(&pdev->dev, NULL);
  78. if (IS_ERR(trng->clk)) {
  79. ret = PTR_ERR(trng->clk);
  80. pr_crit("%s: Cannot get DTRNG clock\n", __func__);
  81. return PTR_ERR(trng->clk);
  82. }
  83. ret = clk_prepare_enable(trng->clk);
  84. if (ret) {
  85. pr_crit("%s: Unable to enable DTRNG clock\n", __func__);
  86. return ret;
  87. }
  88. trng->rng.name = pdev->name;
  89. trng->rng.init = ingenic_trng_init;
  90. trng->rng.cleanup = ingenic_trng_cleanup;
  91. trng->rng.read = ingenic_trng_read;
  92. ret = hwrng_register(&trng->rng);
  93. if (ret) {
  94. dev_err(&pdev->dev, "Failed to register hwrng\n");
  95. goto err_unprepare_clk;
  96. }
  97. platform_set_drvdata(pdev, trng);
  98. dev_info(&pdev->dev, "Ingenic DTRNG driver registered\n");
  99. return 0;
  100. err_unprepare_clk:
  101. clk_disable_unprepare(trng->clk);
  102. return ret;
  103. }
  104. static int ingenic_trng_remove(struct platform_device *pdev)
  105. {
  106. struct ingenic_trng *trng = platform_get_drvdata(pdev);
  107. unsigned int ctrl;
  108. hwrng_unregister(&trng->rng);
  109. ctrl = readl(trng->base + TRNG_REG_CFG_OFFSET);
  110. ctrl &= ~CFG_GEN_EN;
  111. writel(ctrl, trng->base + TRNG_REG_CFG_OFFSET);
  112. clk_disable_unprepare(trng->clk);
  113. return 0;
  114. }
  115. static const struct of_device_id ingenic_trng_of_match[] = {
  116. { .compatible = "ingenic,x1830-dtrng" },
  117. { /* sentinel */ }
  118. };
  119. MODULE_DEVICE_TABLE(of, ingenic_trng_of_match);
  120. static struct platform_driver ingenic_trng_driver = {
  121. .probe = ingenic_trng_probe,
  122. .remove = ingenic_trng_remove,
  123. .driver = {
  124. .name = "ingenic-trng",
  125. .of_match_table = ingenic_trng_of_match,
  126. },
  127. };
  128. module_platform_driver(ingenic_trng_driver);
  129. MODULE_LICENSE("GPL");
  130. MODULE_AUTHOR("漆鹏振 (Qi Pengzhen) <[email protected]>");
  131. MODULE_AUTHOR("周琰杰 (Zhou Yanjie) <[email protected]>");
  132. MODULE_DESCRIPTION("Ingenic True Random Number Generator driver");