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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 | // SPDX-License-Identifier: GPL-2.0 /* * Ingenic Random Number Generator driver * Copyright (c) 2017 PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com> * Copyright (c) 2020 周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com> */ #include <linux/err.h> #include <linux/kernel.h> #include <linux/hw_random.h> #include <linux/io.h> #include <linux/iopoll.h> #include <linux/module.h> #include <linux/of.h> #include <linux/platform_device.h> #include <linux/slab.h> /* RNG register offsets */ #define RNG_REG_ERNG_OFFSET 0x0 #define RNG_REG_RNG_OFFSET 0x4 /* bits within the ERND register */ #define ERNG_READY BIT(31) #define ERNG_ENABLE BIT(0) enum ingenic_rng_version { ID_JZ4780, ID_X1000, }; /* Device associated memory */ struct ingenic_rng { enum ingenic_rng_version version; void __iomem *base; struct hwrng rng; }; static int ingenic_rng_init(struct hwrng *rng) { struct ingenic_rng *priv = container_of(rng, struct ingenic_rng, rng); writel(ERNG_ENABLE, priv->base + RNG_REG_ERNG_OFFSET); return 0; } static void ingenic_rng_cleanup(struct hwrng *rng) { struct ingenic_rng *priv = container_of(rng, struct ingenic_rng, rng); writel(0, priv->base + RNG_REG_ERNG_OFFSET); } static int ingenic_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) { struct ingenic_rng *priv = container_of(rng, struct ingenic_rng, rng); u32 *data = buf; u32 status; int ret; if (priv->version >= ID_X1000) { ret = readl_poll_timeout(priv->base + RNG_REG_ERNG_OFFSET, status, status & ERNG_READY, 10, 1000); if (ret == -ETIMEDOUT) { pr_err("%s: Wait for RNG data ready timeout\n", __func__); return ret; } } else { /* * A delay is required so that the current RNG data is not bit shifted * version of previous RNG data which could happen if random data is * read continuously from this device. */ udelay(20); } *data = readl(priv->base + RNG_REG_RNG_OFFSET); return 4; } static int ingenic_rng_probe(struct platform_device *pdev) { struct ingenic_rng *priv; int ret; priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); if (!priv) return -ENOMEM; priv->base = devm_platform_ioremap_resource(pdev, 0); if (IS_ERR(priv->base)) { pr_err("%s: Failed to map RNG registers\n", __func__); return PTR_ERR(priv->base); } priv->version = (enum ingenic_rng_version)(uintptr_t)of_device_get_match_data(&pdev->dev); priv->rng.name = pdev->name; priv->rng.init = ingenic_rng_init; priv->rng.cleanup = ingenic_rng_cleanup; priv->rng.read = ingenic_rng_read; ret = hwrng_register(&priv->rng); if (ret) { dev_err(&pdev->dev, "Failed to register hwrng\n"); return ret; } platform_set_drvdata(pdev, priv); dev_info(&pdev->dev, "Ingenic RNG driver registered\n"); return 0; } static void ingenic_rng_remove(struct platform_device *pdev) { struct ingenic_rng *priv = platform_get_drvdata(pdev); hwrng_unregister(&priv->rng); writel(0, priv->base + RNG_REG_ERNG_OFFSET); } static const struct of_device_id ingenic_rng_of_match[] = { { .compatible = "ingenic,jz4780-rng", .data = (void *) ID_JZ4780 }, { .compatible = "ingenic,x1000-rng", .data = (void *) ID_X1000 }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, ingenic_rng_of_match); static struct platform_driver ingenic_rng_driver = { .probe = ingenic_rng_probe, .remove_new = ingenic_rng_remove, .driver = { .name = "ingenic-rng", .of_match_table = ingenic_rng_of_match, }, }; module_platform_driver(ingenic_rng_driver); MODULE_LICENSE("GPL"); MODULE_AUTHOR("PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>"); MODULE_AUTHOR("周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>"); MODULE_DESCRIPTION("Ingenic Random Number Generator driver"); |