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