// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) 2016 HiSilicon Co., Ltd. */ #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; int ret; rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL); if (!rng) return -ENOMEM; platform_set_drvdata(pdev, rng); rng->base = devm_platform_ioremap_resource(pdev, 0); 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");