projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| afc39d6e KW |
1 | /* |
| 2 | * Copyright (C) 2016 HiSilicon Co., Ltd. | |
| 3 | * | |
| 4 | * This program is free software; you can redistribute it and/or modify | |
| 5 | * it under the terms of the GNU General Public License version 2 as | |
| 6 | * published by the Free Software Foundation. | |
| 7 | */ | |
| 8 | ||
| 9 | #include <linux/err.h> | |
| 10 | #include <linux/kernel.h> | |
| 11 | #include <linux/hw_random.h> | |
| 12 | #include <linux/io.h> | |
| 13 | #include <linux/module.h> | |
| 14 | #include <linux/of.h> | |
| 15 | #include <linux/platform_device.h> | |
| 16 | #include <linux/random.h> | |
| 17 | ||
| 18 | #define RNG_SEED 0x0 | |
| 19 | #define RNG_CTRL 0x4 | |
| 20 | #define RNG_SEED_SEL BIT(2) | |
| 21 | #define RNG_RING_EN BIT(1) | |
| 22 | #define RNG_EN BIT(0) | |
| 23 | #define RNG_RAN_NUM 0x10 | |
| 24 | #define RNG_PHY_SEED 0x14 | |
| 25 | ||
| 26 | #define to_hisi_rng(p) container_of(p, struct hisi_rng, rng) | |
| 27 | ||
| 28 | static int seed_sel; | |
| 29 | module_param(seed_sel, int, S_IRUGO); | |
| 30 | MODULE_PARM_DESC(seed_sel, "Auto reload seed. 0, use LFSR(default); 1, use ring oscillator."); | |
| 31 | ||
| 32 | struct hisi_rng { | |
| 33 | void __iomem *base; | |
| 34 | struct hwrng rng; | |
| 35 | }; | |
| 36 | ||
| 37 | static int hisi_rng_init(struct hwrng *rng) | |
| 38 | { | |
| 39 | struct hisi_rng *hrng = to_hisi_rng(rng); | |
| 40 | int val = RNG_EN; | |
| 41 | u32 seed; | |
| 42 | ||
| 43 | /* get a random number as initial seed */ | |
| 44 | get_random_bytes(&seed, sizeof(seed)); | |
| 45 | ||
| 46 | writel_relaxed(seed, hrng->base + RNG_SEED); | |
| 47 | ||
| 48 | /** | |
| 49 | * The seed is reload periodically, there are two choice | |
| 50 | * of seeds, default seed using the value from LFSR, or | |
| 51 | * will use seed generated by ring oscillator. | |
| 52 | */ | |
| 53 | if (seed_sel == 1) | |
| 54 | val |= RNG_RING_EN | RNG_SEED_SEL; | |
| 55 | ||
| 56 | writel_relaxed(val, hrng->base + RNG_CTRL); | |
| 57 | return 0; | |
| 58 | } | |
| 59 | ||
| 60 | static void hisi_rng_cleanup(struct hwrng *rng) | |
| 61 | { | |
| 62 | struct hisi_rng *hrng = to_hisi_rng(rng); | |
| 63 | ||
| 64 | writel_relaxed(0, hrng->base + RNG_CTRL); | |
| 65 | } | |
| 66 | ||
| 67 | static int hisi_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) | |
| 68 | { | |
| 69 | struct hisi_rng *hrng = to_hisi_rng(rng); | |
| 70 | u32 *data = buf; | |
| 71 | ||
| 72 | *data = readl_relaxed(hrng->base + RNG_RAN_NUM); | |
| 73 | return 4; | |
| 74 | } | |
| 75 | ||
| 76 | static int hisi_rng_probe(struct platform_device *pdev) | |
| 77 | { | |
| 78 | struct hisi_rng *rng; | |
| 79 | struct resource *res; | |
| 80 | int ret; | |
| 81 | ||
| 82 | rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL); | |
| 83 | if (!rng) | |
| 84 | return -ENOMEM; | |
| 85 | ||
| 86 | platform_set_drvdata(pdev, rng); | |
| 87 | ||
| 88 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
| 89 | rng->base = devm_ioremap_resource(&pdev->dev, res); | |
| 90 | if (IS_ERR(rng->base)) | |
| 91 | return PTR_ERR(rng->base); | |
| 92 | ||
| 93 | rng->rng.name = pdev->name; | |
| 94 | rng->rng.init = hisi_rng_init; | |
| 95 | rng->rng.cleanup = hisi_rng_cleanup; | |
| 96 | rng->rng.read = hisi_rng_read; | |
| 97 | ||
| 98 | ret = devm_hwrng_register(&pdev->dev, &rng->rng); | |
| 99 | if (ret) { | |
| 100 | dev_err(&pdev->dev, "failed to register hwrng\n"); | |
| 101 | return ret; | |
| 102 | } | |
| 103 | ||
| 104 | return 0; | |
| 105 | } | |
| 106 | ||
| 107 | static const struct of_device_id hisi_rng_dt_ids[] = { | |
| 108 | { .compatible = "hisilicon,hip04-rng" }, | |
| 109 | { .compatible = "hisilicon,hip05-rng" }, | |
| 110 | { } | |
| 111 | }; | |
| 112 | MODULE_DEVICE_TABLE(of, hisi_rng_dt_ids); | |
| 113 | ||
| 114 | static struct platform_driver hisi_rng_driver = { | |
| 115 | .probe = hisi_rng_probe, | |
| 116 | .driver = { | |
| 117 | .name = "hisi-rng", | |
| 118 | .of_match_table = of_match_ptr(hisi_rng_dt_ids), | |
| 119 | }, | |
| 120 | }; | |
| 121 | ||
| 122 | module_platform_driver(hisi_rng_driver); | |
| 123 | ||
| 124 | MODULE_LICENSE("GPL"); | |
| 125 | MODULE_AUTHOR("Kefeng Wang <wangkefeng.wang@huawei>"); | |
| 126 | MODULE_DESCRIPTION("Hisilicon random number generator driver"); |