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121 lines
2.7 KiB
121 lines
2.7 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Copyright (C) 2016 HiSilicon Co., Ltd. |
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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/module.h> |
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#include <linux/of.h> |
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#include <linux/platform_device.h> |
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#include <linux/random.h> |
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#define RNG_SEED 0x0 |
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#define RNG_CTRL 0x4 |
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#define RNG_SEED_SEL BIT(2) |
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#define RNG_RING_EN BIT(1) |
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#define RNG_EN BIT(0) |
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#define RNG_RAN_NUM 0x10 |
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#define RNG_PHY_SEED 0x14 |
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#define to_hisi_rng(p) container_of(p, struct hisi_rng, rng) |
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static int seed_sel; |
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module_param(seed_sel, int, S_IRUGO); |
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MODULE_PARM_DESC(seed_sel, "Auto reload seed. 0, use LFSR(default); 1, use ring oscillator."); |
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struct hisi_rng { |
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void __iomem *base; |
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struct hwrng rng; |
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}; |
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static int hisi_rng_init(struct hwrng *rng) |
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{ |
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struct hisi_rng *hrng = to_hisi_rng(rng); |
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int val = RNG_EN; |
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u32 seed; |
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/* get a random number as initial seed */ |
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get_random_bytes(&seed, sizeof(seed)); |
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writel_relaxed(seed, hrng->base + RNG_SEED); |
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/** |
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* The seed is reload periodically, there are two choice |
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* of seeds, default seed using the value from LFSR, or |
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* will use seed generated by ring oscillator. |
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*/ |
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if (seed_sel == 1) |
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val |= RNG_RING_EN | RNG_SEED_SEL; |
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writel_relaxed(val, hrng->base + RNG_CTRL); |
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return 0; |
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} |
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static void hisi_rng_cleanup(struct hwrng *rng) |
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{ |
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struct hisi_rng *hrng = to_hisi_rng(rng); |
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writel_relaxed(0, hrng->base + RNG_CTRL); |
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} |
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static int hisi_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) |
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{ |
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struct hisi_rng *hrng = to_hisi_rng(rng); |
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u32 *data = buf; |
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*data = readl_relaxed(hrng->base + RNG_RAN_NUM); |
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return 4; |
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} |
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static int hisi_rng_probe(struct platform_device *pdev) |
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{ |
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struct hisi_rng *rng; |
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int ret; |
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rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL); |
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if (!rng) |
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return -ENOMEM; |
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platform_set_drvdata(pdev, rng); |
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rng->base = devm_platform_ioremap_resource(pdev, 0); |
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if (IS_ERR(rng->base)) |
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return PTR_ERR(rng->base); |
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rng->rng.name = pdev->name; |
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rng->rng.init = hisi_rng_init; |
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rng->rng.cleanup = hisi_rng_cleanup; |
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rng->rng.read = hisi_rng_read; |
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ret = devm_hwrng_register(&pdev->dev, &rng->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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return 0; |
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} |
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static const struct of_device_id hisi_rng_dt_ids[] __maybe_unused = { |
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{ .compatible = "hisilicon,hip04-rng" }, |
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{ .compatible = "hisilicon,hip05-rng" }, |
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{ } |
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}; |
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MODULE_DEVICE_TABLE(of, hisi_rng_dt_ids); |
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static struct platform_driver hisi_rng_driver = { |
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.probe = hisi_rng_probe, |
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.driver = { |
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.name = "hisi-rng", |
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.of_match_table = of_match_ptr(hisi_rng_dt_ids), |
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}, |
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}; |
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module_platform_driver(hisi_rng_driver); |
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MODULE_LICENSE("GPL"); |
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MODULE_AUTHOR("Kefeng Wang <wangkefeng.wang@huawei>"); |
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MODULE_DESCRIPTION("Hisilicon random number generator driver");
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