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165 lines
4.0 KiB
165 lines
4.0 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Ingenic True Random Number Generator driver |
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* Copyright (c) 2019 漆鹏振 (Qi Pengzhen) <[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/clk.h> |
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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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/* DTRNG register offsets */ |
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#define TRNG_REG_CFG_OFFSET 0x00 |
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#define TRNG_REG_RANDOMNUM_OFFSET 0x04 |
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#define TRNG_REG_STATUS_OFFSET 0x08 |
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/* bits within the CFG register */ |
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#define CFG_RDY_CLR BIT(12) |
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#define CFG_INT_MASK BIT(11) |
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#define CFG_GEN_EN BIT(0) |
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/* bits within the STATUS register */ |
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#define STATUS_RANDOM_RDY BIT(0) |
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struct ingenic_trng { |
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void __iomem *base; |
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struct clk *clk; |
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struct hwrng rng; |
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}; |
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static int ingenic_trng_init(struct hwrng *rng) |
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{ |
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struct ingenic_trng *trng = container_of(rng, struct ingenic_trng, rng); |
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unsigned int ctrl; |
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ctrl = readl(trng->base + TRNG_REG_CFG_OFFSET); |
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ctrl |= CFG_GEN_EN; |
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writel(ctrl, trng->base + TRNG_REG_CFG_OFFSET); |
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return 0; |
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} |
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static void ingenic_trng_cleanup(struct hwrng *rng) |
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{ |
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struct ingenic_trng *trng = container_of(rng, struct ingenic_trng, rng); |
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unsigned int ctrl; |
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ctrl = readl(trng->base + TRNG_REG_CFG_OFFSET); |
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ctrl &= ~CFG_GEN_EN; |
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writel(ctrl, trng->base + TRNG_REG_CFG_OFFSET); |
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} |
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static int ingenic_trng_read(struct hwrng *rng, void *buf, size_t max, bool wait) |
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{ |
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struct ingenic_trng *trng = container_of(rng, struct ingenic_trng, rng); |
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u32 *data = buf; |
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u32 status; |
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int ret; |
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ret = readl_poll_timeout(trng->base + TRNG_REG_STATUS_OFFSET, status, |
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status & STATUS_RANDOM_RDY, 10, 1000); |
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if (ret == -ETIMEDOUT) { |
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pr_err("%s: Wait for DTRNG data ready timeout\n", __func__); |
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return ret; |
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} |
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*data = readl(trng->base + TRNG_REG_RANDOMNUM_OFFSET); |
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return 4; |
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} |
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static int ingenic_trng_probe(struct platform_device *pdev) |
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{ |
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struct ingenic_trng *trng; |
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int ret; |
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trng = devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL); |
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if (!trng) |
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return -ENOMEM; |
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trng->base = devm_platform_ioremap_resource(pdev, 0); |
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if (IS_ERR(trng->base)) { |
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pr_err("%s: Failed to map DTRNG registers\n", __func__); |
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ret = PTR_ERR(trng->base); |
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return PTR_ERR(trng->base); |
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} |
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trng->clk = devm_clk_get(&pdev->dev, NULL); |
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if (IS_ERR(trng->clk)) { |
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ret = PTR_ERR(trng->clk); |
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pr_crit("%s: Cannot get DTRNG clock\n", __func__); |
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return PTR_ERR(trng->clk); |
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} |
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ret = clk_prepare_enable(trng->clk); |
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if (ret) { |
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pr_crit("%s: Unable to enable DTRNG clock\n", __func__); |
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return ret; |
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} |
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trng->rng.name = pdev->name; |
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trng->rng.init = ingenic_trng_init; |
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trng->rng.cleanup = ingenic_trng_cleanup; |
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trng->rng.read = ingenic_trng_read; |
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ret = hwrng_register(&trng->rng); |
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if (ret) { |
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dev_err(&pdev->dev, "Failed to register hwrng\n"); |
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goto err_unprepare_clk; |
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} |
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platform_set_drvdata(pdev, trng); |
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dev_info(&pdev->dev, "Ingenic DTRNG driver registered\n"); |
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return 0; |
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err_unprepare_clk: |
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clk_disable_unprepare(trng->clk); |
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return ret; |
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} |
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static int ingenic_trng_remove(struct platform_device *pdev) |
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{ |
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struct ingenic_trng *trng = platform_get_drvdata(pdev); |
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unsigned int ctrl; |
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hwrng_unregister(&trng->rng); |
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ctrl = readl(trng->base + TRNG_REG_CFG_OFFSET); |
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ctrl &= ~CFG_GEN_EN; |
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writel(ctrl, trng->base + TRNG_REG_CFG_OFFSET); |
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clk_disable_unprepare(trng->clk); |
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return 0; |
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} |
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static const struct of_device_id ingenic_trng_of_match[] = { |
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{ .compatible = "ingenic,x1830-dtrng" }, |
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{ /* sentinel */ } |
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}; |
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MODULE_DEVICE_TABLE(of, ingenic_trng_of_match); |
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static struct platform_driver ingenic_trng_driver = { |
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.probe = ingenic_trng_probe, |
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.remove = ingenic_trng_remove, |
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.driver = { |
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.name = "ingenic-trng", |
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.of_match_table = ingenic_trng_of_match, |
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}, |
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}; |
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module_platform_driver(ingenic_trng_driver); |
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MODULE_LICENSE("GPL"); |
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MODULE_AUTHOR("漆鹏振 (Qi Pengzhen) <[email protected]>"); |
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MODULE_AUTHOR("周琰杰 (Zhou Yanjie) <[email protected]>"); |
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MODULE_DESCRIPTION("Ingenic True Random Number Generator driver");
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