150 lines
3.6 KiB
C
150 lines
3.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Ingenic Random Number Generator driver
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* Copyright (c) 2017 PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
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* Copyright (c) 2020 周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>
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*/
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#include <linux/err.h>
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#include <linux/kernel.h>
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#include <linux/hw_random.h>
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#include <linux/io.h>
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#include <linux/iopoll.h>
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#include <linux/module.h>
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#include <linux/of_device.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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/* RNG register offsets */
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#define RNG_REG_ERNG_OFFSET 0x0
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#define RNG_REG_RNG_OFFSET 0x4
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/* bits within the ERND register */
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#define ERNG_READY BIT(31)
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#define ERNG_ENABLE BIT(0)
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enum ingenic_rng_version {
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ID_JZ4780,
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ID_X1000,
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};
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/* Device associated memory */
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struct ingenic_rng {
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enum ingenic_rng_version version;
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void __iomem *base;
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struct hwrng rng;
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};
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static int ingenic_rng_init(struct hwrng *rng)
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{
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struct ingenic_rng *priv = container_of(rng, struct ingenic_rng, rng);
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writel(ERNG_ENABLE, priv->base + RNG_REG_ERNG_OFFSET);
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return 0;
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}
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static void ingenic_rng_cleanup(struct hwrng *rng)
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{
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struct ingenic_rng *priv = container_of(rng, struct ingenic_rng, rng);
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writel(0, priv->base + RNG_REG_ERNG_OFFSET);
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}
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static int ingenic_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
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{
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struct ingenic_rng *priv = container_of(rng, struct ingenic_rng, rng);
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u32 *data = buf;
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u32 status;
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int ret;
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if (priv->version >= ID_X1000) {
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ret = readl_poll_timeout(priv->base + RNG_REG_ERNG_OFFSET, status,
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status & ERNG_READY, 10, 1000);
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if (ret == -ETIMEDOUT) {
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pr_err("%s: Wait for RNG data ready timeout\n", __func__);
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return ret;
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}
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} else {
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/*
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* A delay is required so that the current RNG data is not bit shifted
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* version of previous RNG data which could happen if random data is
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* read continuously from this device.
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*/
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udelay(20);
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}
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*data = readl(priv->base + RNG_REG_RNG_OFFSET);
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return 4;
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}
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static int ingenic_rng_probe(struct platform_device *pdev)
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{
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struct ingenic_rng *priv;
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int ret;
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priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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priv->base = devm_platform_ioremap_resource(pdev, 0);
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if (IS_ERR(priv->base)) {
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pr_err("%s: Failed to map RNG registers\n", __func__);
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return PTR_ERR(priv->base);
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}
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priv->version = (enum ingenic_rng_version)of_device_get_match_data(&pdev->dev);
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priv->rng.name = pdev->name;
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priv->rng.init = ingenic_rng_init;
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priv->rng.cleanup = ingenic_rng_cleanup;
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priv->rng.read = ingenic_rng_read;
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ret = hwrng_register(&priv->rng);
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if (ret) {
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dev_err(&pdev->dev, "Failed to register hwrng\n");
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return ret;
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}
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platform_set_drvdata(pdev, priv);
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dev_info(&pdev->dev, "Ingenic RNG driver registered\n");
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return 0;
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}
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static int ingenic_rng_remove(struct platform_device *pdev)
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{
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struct ingenic_rng *priv = platform_get_drvdata(pdev);
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hwrng_unregister(&priv->rng);
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writel(0, priv->base + RNG_REG_ERNG_OFFSET);
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return 0;
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}
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static const struct of_device_id ingenic_rng_of_match[] = {
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{ .compatible = "ingenic,jz4780-rng", .data = (void *) ID_JZ4780 },
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{ .compatible = "ingenic,x1000-rng", .data = (void *) ID_X1000 },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(of, ingenic_rng_of_match);
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static struct platform_driver ingenic_rng_driver = {
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.probe = ingenic_rng_probe,
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.remove = ingenic_rng_remove,
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.driver = {
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.name = "ingenic-rng",
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.of_match_table = ingenic_rng_of_match,
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},
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};
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module_platform_driver(ingenic_rng_driver);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>");
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MODULE_AUTHOR("周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>");
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MODULE_DESCRIPTION("Ingenic Random Number Generator driver");
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