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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright (C) 2016 HiSilicon Co., Ltd.4 */5 6#include <linux/err.h>7#include <linux/kernel.h>8#include <linux/hw_random.h>9#include <linux/io.h>10#include <linux/module.h>11#include <linux/of.h>12#include <linux/platform_device.h>13#include <linux/random.h>14 15#define RNG_SEED 0x016#define RNG_CTRL 0x417 #define RNG_SEED_SEL BIT(2)18 #define RNG_RING_EN BIT(1)19 #define RNG_EN BIT(0)20#define RNG_RAN_NUM 0x1021#define RNG_PHY_SEED 0x1422 23#define to_hisi_rng(p) container_of(p, struct hisi_rng, rng)24 25static int seed_sel;26module_param(seed_sel, int, S_IRUGO);27MODULE_PARM_DESC(seed_sel, "Auto reload seed. 0, use LFSR(default); 1, use ring oscillator.");28 29struct hisi_rng {30 void __iomem *base;31 struct hwrng rng;32};33 34static int hisi_rng_init(struct hwrng *rng)35{36 struct hisi_rng *hrng = to_hisi_rng(rng);37 int val = RNG_EN;38 u32 seed;39 40 /* get a random number as initial seed */41 get_random_bytes(&seed, sizeof(seed));42 43 writel_relaxed(seed, hrng->base + RNG_SEED);44 45 /**46 * The seed is reload periodically, there are two choice47 * of seeds, default seed using the value from LFSR, or48 * will use seed generated by ring oscillator.49 */50 if (seed_sel == 1)51 val |= RNG_RING_EN | RNG_SEED_SEL;52 53 writel_relaxed(val, hrng->base + RNG_CTRL);54 return 0;55}56 57static void hisi_rng_cleanup(struct hwrng *rng)58{59 struct hisi_rng *hrng = to_hisi_rng(rng);60 61 writel_relaxed(0, hrng->base + RNG_CTRL);62}63 64static int hisi_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)65{66 struct hisi_rng *hrng = to_hisi_rng(rng);67 u32 *data = buf;68 69 *data = readl_relaxed(hrng->base + RNG_RAN_NUM);70 return 4;71}72 73static int hisi_rng_probe(struct platform_device *pdev)74{75 struct hisi_rng *rng;76 int ret;77 78 rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL);79 if (!rng)80 return -ENOMEM;81 82 rng->base = devm_platform_ioremap_resource(pdev, 0);83 if (IS_ERR(rng->base))84 return PTR_ERR(rng->base);85 86 rng->rng.name = pdev->name;87 rng->rng.init = hisi_rng_init;88 rng->rng.cleanup = hisi_rng_cleanup;89 rng->rng.read = hisi_rng_read;90 91 ret = devm_hwrng_register(&pdev->dev, &rng->rng);92 if (ret)93 return dev_err_probe(&pdev->dev, ret, "failed to register hwrng\n");94 95 return 0;96}97 98static const struct of_device_id hisi_rng_dt_ids[] __maybe_unused = {99 { .compatible = "hisilicon,hip04-rng" },100 { .compatible = "hisilicon,hip05-rng" },101 { }102};103MODULE_DEVICE_TABLE(of, hisi_rng_dt_ids);104 105static struct platform_driver hisi_rng_driver = {106 .probe = hisi_rng_probe,107 .driver = {108 .name = "hisi-rng",109 .of_match_table = of_match_ptr(hisi_rng_dt_ids),110 },111};112 113module_platform_driver(hisi_rng_driver);114 115MODULE_LICENSE("GPL");116MODULE_AUTHOR("Kefeng Wang <wangkefeng.wang@huawei>");117MODULE_DESCRIPTION("Hisilicon random number generator driver");118