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