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/of_device.h> 16 #include <linux/platform_device.h> 17 #include <linux/slab.h> 18 19 /* DTRNG register offsets */ 20 #define TRNG_REG_CFG_OFFSET 0x00 21 #define TRNG_REG_RANDOMNUM_OFFSET 0x04 22 #define TRNG_REG_STATUS_OFFSET 0x08 23 24 /* bits within the CFG register */ 25 #define CFG_RDY_CLR BIT(12) 26 #define CFG_INT_MASK BIT(11) 27 #define CFG_GEN_EN BIT(0) 28 29 /* bits within the STATUS register */ 30 #define STATUS_RANDOM_RDY BIT(0) 31 32 struct ingenic_trng { 33 void __iomem *base; 34 struct clk *clk; 35 struct hwrng rng; 36 }; 37 38 static int ingenic_trng_init(struct hwrng *rng) 39 { 40 struct ingenic_trng *trng = container_of(rng, struct ingenic_trng, rng); 41 unsigned int ctrl; 42 43 ctrl = readl(trng->base + TRNG_REG_CFG_OFFSET); 44 ctrl |= CFG_GEN_EN; 45 writel(ctrl, trng->base + TRNG_REG_CFG_OFFSET); 46 47 return 0; 48 } 49 50 static void ingenic_trng_cleanup(struct hwrng *rng) 51 { 52 struct ingenic_trng *trng = container_of(rng, struct ingenic_trng, rng); 53 unsigned int ctrl; 54 55 ctrl = readl(trng->base + TRNG_REG_CFG_OFFSET); 56 ctrl &= ~CFG_GEN_EN; 57 writel(ctrl, trng->base + TRNG_REG_CFG_OFFSET); 58 } 59 60 static int ingenic_trng_read(struct hwrng *rng, void *buf, size_t max, bool wait) 61 { 62 struct ingenic_trng *trng = container_of(rng, struct ingenic_trng, rng); 63 u32 *data = buf; 64 u32 status; 65 int ret; 66 67 ret = readl_poll_timeout(trng->base + TRNG_REG_STATUS_OFFSET, status, 68 status & STATUS_RANDOM_RDY, 10, 1000); 69 if (ret == -ETIMEDOUT) { 70 pr_err("%s: Wait for DTRNG data ready timeout\n", __func__); 71 return ret; 72 } 73 74 *data = readl(trng->base + TRNG_REG_RANDOMNUM_OFFSET); 75 76 return 4; 77 } 78 79 static int ingenic_trng_probe(struct platform_device *pdev) 80 { 81 struct ingenic_trng *trng; 82 int ret; 83 84 trng = devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL); 85 if (!trng) 86 return -ENOMEM; 87 88 trng->base = devm_platform_ioremap_resource(pdev, 0); 89 if (IS_ERR(trng->base)) { 90 pr_err("%s: Failed to map DTRNG registers\n", __func__); 91 ret = PTR_ERR(trng->base); 92 return PTR_ERR(trng->base); 93 } 94 95 trng->clk = devm_clk_get(&pdev->dev, NULL); 96 if (IS_ERR(trng->clk)) { 97 ret = PTR_ERR(trng->clk); 98 pr_crit("%s: Cannot get DTRNG clock\n", __func__); 99 return PTR_ERR(trng->clk); 100 } 101 102 ret = clk_prepare_enable(trng->clk); 103 if (ret) { 104 pr_crit("%s: Unable to enable DTRNG clock\n", __func__); 105 return ret; 106 } 107 108 trng->rng.name = pdev->name; 109 trng->rng.init = ingenic_trng_init; 110 trng->rng.cleanup = ingenic_trng_cleanup; 111 trng->rng.read = ingenic_trng_read; 112 113 ret = hwrng_register(&trng->rng); 114 if (ret) { 115 dev_err(&pdev->dev, "Failed to register hwrng\n"); 116 return ret; 117 } 118 119 platform_set_drvdata(pdev, trng); 120 121 dev_info(&pdev->dev, "Ingenic DTRNG driver registered\n"); 122 return 0; 123 } 124 125 static int ingenic_trng_remove(struct platform_device *pdev) 126 { 127 struct ingenic_trng *trng = platform_get_drvdata(pdev); 128 unsigned int ctrl; 129 130 hwrng_unregister(&trng->rng); 131 132 ctrl = readl(trng->base + TRNG_REG_CFG_OFFSET); 133 ctrl &= ~CFG_GEN_EN; 134 writel(ctrl, trng->base + TRNG_REG_CFG_OFFSET); 135 136 clk_disable_unprepare(trng->clk); 137 138 return 0; 139 } 140 141 static const struct of_device_id ingenic_trng_of_match[] = { 142 { .compatible = "ingenic,x1830-dtrng" }, 143 { /* sentinel */ } 144 }; 145 MODULE_DEVICE_TABLE(of, ingenic_trng_of_match); 146 147 static struct platform_driver ingenic_trng_driver = { 148 .probe = ingenic_trng_probe, 149 .remove = ingenic_trng_remove, 150 .driver = { 151 .name = "ingenic-trng", 152 .of_match_table = ingenic_trng_of_match, 153 }, 154 }; 155 156 module_platform_driver(ingenic_trng_driver); 157 158 MODULE_LICENSE("GPL"); 159 MODULE_AUTHOR("漆鹏振 (Qi Pengzhen) <aric.pzqi@ingenic.com>"); 160 MODULE_AUTHOR("周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>"); 161 MODULE_DESCRIPTION("Ingenic True Random Number Generator driver"); 162