131 lines · c
1// SPDX-License-Identifier: GPL-2.02/*3 * Ingenic True Random Number Generator driver4 * 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 0x0021#define TRNG_REG_RANDOMNUM_OFFSET 0x0422#define TRNG_REG_STATUS_OFFSET 0x0823 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 30struct ingenic_trng {31 void __iomem *base;32 struct hwrng rng;33};34 35static 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 47static 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 57static 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 76static 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 111static const struct of_device_id ingenic_trng_of_match[] = {112 { .compatible = "ingenic,x1830-dtrng" },113 { /* sentinel */ }114};115MODULE_DEVICE_TABLE(of, ingenic_trng_of_match);116 117static 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 125module_platform_driver(ingenic_trng_driver);126 127MODULE_LICENSE("GPL");128MODULE_AUTHOR("漆鹏振 (Qi Pengzhen) <aric.pzqi@ingenic.com>");129MODULE_AUTHOR("周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>");130MODULE_DESCRIPTION("Ingenic True Random Number Generator driver");131