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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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 | // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause /* * Copyright (c) 2016 BayLibre, SAS. * Author: Neil Armstrong <narmstrong@baylibre.com> * Copyright (C) 2014 Amlogic, Inc. */ #include <linux/err.h> #include <linux/module.h> #include <linux/io.h> #include <linux/platform_device.h> #include <linux/hw_random.h> #include <linux/slab.h> #include <linux/types.h> #include <linux/of.h> #include <linux/clk.h> #include <linux/iopoll.h> #define RNG_DATA 0x00 #define RNG_S4_DATA 0x08 #define RNG_S4_CFG 0x00 #define RUN_BIT BIT(0) #define SEED_READY_STS_BIT BIT(31) struct meson_rng_priv { int (*read)(struct hwrng *rng, void *buf, size_t max, bool wait); }; struct meson_rng_data { void __iomem *base; struct hwrng rng; struct device *dev; }; static int meson_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) { struct meson_rng_data *data = container_of(rng, struct meson_rng_data, rng); *(u32 *)buf = readl_relaxed(data->base + RNG_DATA); return sizeof(u32); } static int meson_rng_wait_status(void __iomem *cfg_addr, int bit) { u32 status = 0; int ret; ret = readl_relaxed_poll_timeout_atomic(cfg_addr, status, !(status & bit), 10, 10000); if (ret) return -EBUSY; return 0; } static int meson_s4_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) { struct meson_rng_data *data = container_of(rng, struct meson_rng_data, rng); void __iomem *cfg_addr = data->base + RNG_S4_CFG; int err; writel_relaxed(readl_relaxed(cfg_addr) | SEED_READY_STS_BIT, cfg_addr); err = meson_rng_wait_status(cfg_addr, SEED_READY_STS_BIT); if (err) { dev_err(data->dev, "Seed isn't ready, try again\n"); return err; } err = meson_rng_wait_status(cfg_addr, RUN_BIT); if (err) { dev_err(data->dev, "Can't get random number, try again\n"); return err; } *(u32 *)buf = readl_relaxed(data->base + RNG_S4_DATA); return sizeof(u32); } static int meson_rng_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct meson_rng_data *data; struct clk *core_clk; const struct meson_rng_priv *priv; data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); if (!data) return -ENOMEM; priv = device_get_match_data(&pdev->dev); if (!priv) return -ENODEV; data->base = devm_platform_ioremap_resource(pdev, 0); if (IS_ERR(data->base)) return PTR_ERR(data->base); core_clk = devm_clk_get_optional_enabled(dev, "core"); if (IS_ERR(core_clk)) return dev_err_probe(dev, PTR_ERR(core_clk), "Failed to get core clock\n"); data->rng.name = pdev->name; data->rng.read = priv->read; data->dev = &pdev->dev; return devm_hwrng_register(dev, &data->rng); } static const struct meson_rng_priv meson_rng_priv = { .read = meson_rng_read, }; static const struct meson_rng_priv meson_rng_priv_s4 = { .read = meson_s4_rng_read, }; static const struct of_device_id meson_rng_of_match[] = { { .compatible = "amlogic,meson-rng", .data = (void *)&meson_rng_priv, }, { .compatible = "amlogic,meson-s4-rng", .data = (void *)&meson_rng_priv_s4, }, {}, }; MODULE_DEVICE_TABLE(of, meson_rng_of_match); static struct platform_driver meson_rng_driver = { .probe = meson_rng_probe, .driver = { .name = "meson-rng", .of_match_table = meson_rng_of_match, }, }; module_platform_driver(meson_rng_driver); MODULE_DESCRIPTION("Meson H/W Random Number Generator driver"); MODULE_AUTHOR("Lawrence Mok <lawrence.mok@amlogic.com>"); MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>"); MODULE_LICENSE("Dual BSD/GPL"); |