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/mod_devicetable.h> 15 #include <linux/module.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_GEN_EN BIT(0) 26 27 /* bits within the STATUS register */ 28 #define STATUS_RANDOM_RDY BIT(0) 29 30 struct ingenic_trng { 31 void __iomem *base; 32 struct hwrng rng; 33 }; 34 35 static int ingenic_trng_init(struct hwrng *rng) 36 { 37 struct ingenic_trng *trng = container_of(rng, struct ingenic_trng, rng); 38 unsigned int ctrl; 39 40 ctrl = readl(trng->base + TRNG_REG_CFG_OFFSET); 41 ctrl |= CFG_GEN_EN; 42 writel(ctrl, trng->base + TRNG_REG_CFG_OFFSET); 43 44 return 0; 45 } 46 47 static void ingenic_trng_cleanup(struct hwrng *rng) 48 { 49 struct ingenic_trng *trng = container_of(rng, struct ingenic_trng, rng); 50 unsigned int ctrl; 51 52 ctrl = readl(trng->base + TRNG_REG_CFG_OFFSET); 53 ctrl &= ~CFG_GEN_EN; 54 writel(ctrl, trng->base + TRNG_REG_CFG_OFFSET); 55 } 56 57 static int ingenic_trng_read(struct hwrng *rng, void *buf, size_t max, bool wait) 58 { 59 struct ingenic_trng *trng = container_of(rng, struct ingenic_trng, rng); 60 u32 *data = buf; 61 u32 status; 62 int ret; 63 64 ret = readl_poll_timeout(trng->base + TRNG_REG_STATUS_OFFSET, status, 65 status & STATUS_RANDOM_RDY, 10, 1000); 66 if (ret == -ETIMEDOUT) { 67 pr_err("%s: Wait for DTRNG data ready timeout\n", __func__); 68 return ret; 69 } 70 71 *data = readl(trng->base + TRNG_REG_RANDOMNUM_OFFSET); 72 73 return 4; 74 } 75 76 static int ingenic_trng_probe(struct platform_device *pdev) 77 { 78 struct ingenic_trng *trng; 79 struct clk *clk; 80 int ret; 81 82 trng = devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL); 83 if (!trng) 84 return -ENOMEM; 85 86 trng->base = devm_platform_ioremap_resource(pdev, 0); 87 if (IS_ERR(trng->base)) 88 return dev_err_probe(&pdev->dev, PTR_ERR(trng->base), 89 "%s: Failed to map DTRNG registers\n", __func__); 90 91 clk = devm_clk_get_enabled(&pdev->dev, NULL); 92 if (IS_ERR(clk)) 93 return dev_err_probe(&pdev->dev, PTR_ERR(clk), 94 "%s: Cannot get and enable DTRNG clock\n", __func__); 95 96 trng->rng.name = pdev->name; 97 trng->rng.init = ingenic_trng_init; 98 trng->rng.cleanup = ingenic_trng_cleanup; 99 trng->rng.read = ingenic_trng_read; 100 101 ret = devm_hwrng_register(&pdev->dev, &trng->rng); 102 if (ret) 103 return dev_err_probe(&pdev->dev, ret, "Failed to register hwrng\n"); 104 105 platform_set_drvdata(pdev, trng); 106 107 dev_info(&pdev->dev, "Ingenic DTRNG driver registered\n"); 108 return 0; 109 } 110 111 static const struct of_device_id ingenic_trng_of_match[] = { 112 { .compatible = "ingenic,x1830-dtrng" }, 113 { /* sentinel */ } 114 }; 115 MODULE_DEVICE_TABLE(of, ingenic_trng_of_match); 116 117 static struct platform_driver ingenic_trng_driver = { 118 .probe = ingenic_trng_probe, 119 .driver = { 120 .name = "ingenic-trng", 121 .of_match_table = ingenic_trng_of_match, 122 }, 123 }; 124 125 module_platform_driver(ingenic_trng_driver); 126 127 MODULE_LICENSE("GPL"); 128 MODULE_AUTHOR("漆鹏振 (Qi Pengzhen) <aric.pzqi@ingenic.com>"); 129 MODULE_AUTHOR("周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>"); 130 MODULE_DESCRIPTION("Ingenic True Random Number Generator driver"); 131