diff options
Diffstat (limited to 'drivers/char/hw_random/hisi-rng.c')
| -rw-r--r-- | drivers/char/hw_random/hisi-rng.c | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/drivers/char/hw_random/hisi-rng.c b/drivers/char/hw_random/hisi-rng.c new file mode 100644 index 000000000000..40d96572c591 --- /dev/null +++ b/drivers/char/hw_random/hisi-rng.c @@ -0,0 +1,126 @@ +/* + * 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"); |