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1// SPDX-License-Identifier: GPL-2.02/*3 * Ingenic Random Number Generator driver4 * Copyright (c) 2017 PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>5 * Copyright (c) 2020 周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>6 */7 8#include <linux/err.h>9#include <linux/kernel.h>10#include <linux/hw_random.h>11#include <linux/io.h>12#include <linux/iopoll.h>13#include <linux/module.h>14#include <linux/of.h>15#include <linux/platform_device.h>16#include <linux/slab.h>17 18/* RNG register offsets */19#define RNG_REG_ERNG_OFFSET 0x020#define RNG_REG_RNG_OFFSET 0x421 22/* bits within the ERND register */23#define ERNG_READY BIT(31)24#define ERNG_ENABLE BIT(0)25 26enum ingenic_rng_version {27 ID_JZ4780,28 ID_X1000,29};30 31/* Device associated memory */32struct ingenic_rng {33 enum ingenic_rng_version version;34 35 void __iomem *base;36 struct hwrng rng;37};38 39static int ingenic_rng_init(struct hwrng *rng)40{41 struct ingenic_rng *priv = container_of(rng, struct ingenic_rng, rng);42 43 writel(ERNG_ENABLE, priv->base + RNG_REG_ERNG_OFFSET);44 45 return 0;46}47 48static void ingenic_rng_cleanup(struct hwrng *rng)49{50 struct ingenic_rng *priv = container_of(rng, struct ingenic_rng, rng);51 52 writel(0, priv->base + RNG_REG_ERNG_OFFSET);53}54 55static int ingenic_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)56{57 struct ingenic_rng *priv = container_of(rng, struct ingenic_rng, rng);58 u32 *data = buf;59 u32 status;60 int ret;61 62 if (priv->version >= ID_X1000) {63 ret = readl_poll_timeout(priv->base + RNG_REG_ERNG_OFFSET, status,64 status & ERNG_READY, 10, 1000);65 if (ret == -ETIMEDOUT) {66 pr_err("%s: Wait for RNG data ready timeout\n", __func__);67 return ret;68 }69 } else {70 /*71 * A delay is required so that the current RNG data is not bit shifted72 * version of previous RNG data which could happen if random data is73 * read continuously from this device.74 */75 udelay(20);76 }77 78 *data = readl(priv->base + RNG_REG_RNG_OFFSET);79 80 return 4;81}82 83static int ingenic_rng_probe(struct platform_device *pdev)84{85 struct ingenic_rng *priv;86 int ret;87 88 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);89 if (!priv)90 return -ENOMEM;91 92 priv->base = devm_platform_ioremap_resource(pdev, 0);93 if (IS_ERR(priv->base)) {94 pr_err("%s: Failed to map RNG registers\n", __func__);95 return PTR_ERR(priv->base);96 }97 98 priv->version = (enum ingenic_rng_version)(uintptr_t)of_device_get_match_data(&pdev->dev);99 100 priv->rng.name = pdev->name;101 priv->rng.init = ingenic_rng_init;102 priv->rng.cleanup = ingenic_rng_cleanup;103 priv->rng.read = ingenic_rng_read;104 105 ret = hwrng_register(&priv->rng);106 if (ret) {107 dev_err(&pdev->dev, "Failed to register hwrng\n");108 return ret;109 }110 111 platform_set_drvdata(pdev, priv);112 113 dev_info(&pdev->dev, "Ingenic RNG driver registered\n");114 return 0;115}116 117static void ingenic_rng_remove(struct platform_device *pdev)118{119 struct ingenic_rng *priv = platform_get_drvdata(pdev);120 121 hwrng_unregister(&priv->rng);122 123 writel(0, priv->base + RNG_REG_ERNG_OFFSET);124}125 126static const struct of_device_id ingenic_rng_of_match[] = {127 { .compatible = "ingenic,jz4780-rng", .data = (void *) ID_JZ4780 },128 { .compatible = "ingenic,x1000-rng", .data = (void *) ID_X1000 },129 { /* sentinel */ }130};131MODULE_DEVICE_TABLE(of, ingenic_rng_of_match);132 133static struct platform_driver ingenic_rng_driver = {134 .probe = ingenic_rng_probe,135 .remove_new = ingenic_rng_remove,136 .driver = {137 .name = "ingenic-rng",138 .of_match_table = ingenic_rng_of_match,139 },140};141 142module_platform_driver(ingenic_rng_driver);143 144MODULE_LICENSE("GPL");145MODULE_AUTHOR("PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>");146MODULE_AUTHOR("周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>");147MODULE_DESCRIPTION("Ingenic Random Number Generator driver");148