cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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ingenic-trng.c (4137B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Ingenic True Random Number Generator driver
      4 * 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/module.h>
     15#include <linux/of_device.h>
     16#include <linux/platform_device.h>
     17#include <linux/slab.h>
     18
     19/* DTRNG register offsets */
     20#define TRNG_REG_CFG_OFFSET			0x00
     21#define TRNG_REG_RANDOMNUM_OFFSET	0x04
     22#define TRNG_REG_STATUS_OFFSET		0x08
     23
     24/* bits within the CFG register */
     25#define CFG_RDY_CLR					BIT(12)
     26#define CFG_INT_MASK				BIT(11)
     27#define CFG_GEN_EN					BIT(0)
     28
     29/* bits within the STATUS register */
     30#define STATUS_RANDOM_RDY			BIT(0)
     31
     32struct ingenic_trng {
     33	void __iomem *base;
     34	struct clk *clk;
     35	struct hwrng rng;
     36};
     37
     38static int ingenic_trng_init(struct hwrng *rng)
     39{
     40	struct ingenic_trng *trng = container_of(rng, struct ingenic_trng, rng);
     41	unsigned int ctrl;
     42
     43	ctrl = readl(trng->base + TRNG_REG_CFG_OFFSET);
     44	ctrl |= CFG_GEN_EN;
     45	writel(ctrl, trng->base + TRNG_REG_CFG_OFFSET);
     46
     47	return 0;
     48}
     49
     50static void ingenic_trng_cleanup(struct hwrng *rng)
     51{
     52	struct ingenic_trng *trng = container_of(rng, struct ingenic_trng, rng);
     53	unsigned int ctrl;
     54
     55	ctrl = readl(trng->base + TRNG_REG_CFG_OFFSET);
     56	ctrl &= ~CFG_GEN_EN;
     57	writel(ctrl, trng->base + TRNG_REG_CFG_OFFSET);
     58}
     59
     60static int ingenic_trng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
     61{
     62	struct ingenic_trng *trng = container_of(rng, struct ingenic_trng, rng);
     63	u32 *data = buf;
     64	u32 status;
     65	int ret;
     66
     67	ret = readl_poll_timeout(trng->base + TRNG_REG_STATUS_OFFSET, status,
     68				 status & STATUS_RANDOM_RDY, 10, 1000);
     69	if (ret == -ETIMEDOUT) {
     70		pr_err("%s: Wait for DTRNG data ready timeout\n", __func__);
     71		return ret;
     72	}
     73
     74	*data = readl(trng->base + TRNG_REG_RANDOMNUM_OFFSET);
     75
     76	return 4;
     77}
     78
     79static int ingenic_trng_probe(struct platform_device *pdev)
     80{
     81	struct ingenic_trng *trng;
     82	int ret;
     83
     84	trng = devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL);
     85	if (!trng)
     86		return -ENOMEM;
     87
     88	trng->base = devm_platform_ioremap_resource(pdev, 0);
     89	if (IS_ERR(trng->base)) {
     90		pr_err("%s: Failed to map DTRNG registers\n", __func__);
     91		ret = PTR_ERR(trng->base);
     92		return PTR_ERR(trng->base);
     93	}
     94
     95	trng->clk = devm_clk_get(&pdev->dev, NULL);
     96	if (IS_ERR(trng->clk)) {
     97		ret = PTR_ERR(trng->clk);
     98		pr_crit("%s: Cannot get DTRNG clock\n", __func__);
     99		return PTR_ERR(trng->clk);
    100	}
    101
    102	ret = clk_prepare_enable(trng->clk);
    103	if (ret) {
    104		pr_crit("%s: Unable to enable DTRNG clock\n", __func__);
    105		return ret;
    106	}
    107
    108	trng->rng.name = pdev->name;
    109	trng->rng.init = ingenic_trng_init;
    110	trng->rng.cleanup = ingenic_trng_cleanup;
    111	trng->rng.read = ingenic_trng_read;
    112
    113	ret = hwrng_register(&trng->rng);
    114	if (ret) {
    115		dev_err(&pdev->dev, "Failed to register hwrng\n");
    116		goto err_unprepare_clk;
    117	}
    118
    119	platform_set_drvdata(pdev, trng);
    120
    121	dev_info(&pdev->dev, "Ingenic DTRNG driver registered\n");
    122	return 0;
    123
    124err_unprepare_clk:
    125	clk_disable_unprepare(trng->clk);
    126	return ret;
    127}
    128
    129static int ingenic_trng_remove(struct platform_device *pdev)
    130{
    131	struct ingenic_trng *trng = platform_get_drvdata(pdev);
    132	unsigned int ctrl;
    133
    134	hwrng_unregister(&trng->rng);
    135
    136	ctrl = readl(trng->base + TRNG_REG_CFG_OFFSET);
    137	ctrl &= ~CFG_GEN_EN;
    138	writel(ctrl, trng->base + TRNG_REG_CFG_OFFSET);
    139
    140	clk_disable_unprepare(trng->clk);
    141
    142	return 0;
    143}
    144
    145static const struct of_device_id ingenic_trng_of_match[] = {
    146	{ .compatible = "ingenic,x1830-dtrng" },
    147	{ /* sentinel */ }
    148};
    149MODULE_DEVICE_TABLE(of, ingenic_trng_of_match);
    150
    151static struct platform_driver ingenic_trng_driver = {
    152	.probe		= ingenic_trng_probe,
    153	.remove		= ingenic_trng_remove,
    154	.driver		= {
    155		.name	= "ingenic-trng",
    156		.of_match_table = ingenic_trng_of_match,
    157	},
    158};
    159
    160module_platform_driver(ingenic_trng_driver);
    161
    162MODULE_LICENSE("GPL");
    163MODULE_AUTHOR("漆鹏振 (Qi Pengzhen) <aric.pzqi@ingenic.com>");
    164MODULE_AUTHOR("周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>");
    165MODULE_DESCRIPTION("Ingenic True Random Number Generator driver");