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149 lines
3.6 KiB
149 lines
3.6 KiB
// 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 <[email protected]> |
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* Copyright (c) 2020 周琰杰 (Zhou Yanjie) <[email protected]> |
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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 <[email protected]>"); |
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MODULE_AUTHOR("周琰杰 (Zhou Yanjie) <[email protected]>"); |
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MODULE_DESCRIPTION("Ingenic Random Number Generator driver");
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