// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause /* * Copyright (c) 2016 BayLibre, SAS. * Author: Neil Armstrong <narmstrong@baylibre.com> * Copyright (C) 2014 Amlogic, Inc. */ #include <linux/err.h> #include <linux/module.h> #include <linux/io.h> #include <linux/platform_device.h> #include <linux/hw_random.h> #include <linux/slab.h> #include <linux/types.h> #include <linux/of.h> #include <linux/clk.h> #define RNG_DATA 0x00 struct meson_rng_data { void __iomem *base; struct platform_device *pdev; struct hwrng rng; struct clk *core_clk; }; static int meson_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) { struct meson_rng_data *data = container_of(rng, struct meson_rng_data, rng); *(u32 *)buf = readl_relaxed(data->base + RNG_DATA); return sizeof(u32); } static void meson_rng_clk_disable(void *data) { clk_disable_unprepare(data); } static int meson_rng_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct meson_rng_data *data; struct resource *res; int ret; data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); if (!data) return -ENOMEM; data->pdev = pdev; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); data->base = devm_ioremap_resource(dev, res); if (IS_ERR(data->base)) return PTR_ERR(data->base); data->core_clk = devm_clk_get(dev, "core"); if (IS_ERR(data->core_clk)) data->core_clk = NULL; if (data->core_clk) { ret = clk_prepare_enable(data->core_clk); if (ret) return ret; ret = devm_add_action_or_reset(dev, meson_rng_clk_disable, data->core_clk); if (ret) return ret; } data->rng.name = pdev->name; data->rng.read = meson_rng_read; platform_set_drvdata(pdev, data); return devm_hwrng_register(dev, &data->rng); } static const struct of_device_id meson_rng_of_match[] = { { .compatible = "amlogic,meson-rng", }, {}, }; MODULE_DEVICE_TABLE(of, meson_rng_of_match); static struct platform_driver meson_rng_driver = { .probe = meson_rng_probe, .driver = { .name = "meson-rng", .of_match_table = meson_rng_of_match, }, }; module_platform_driver(meson_rng_driver); MODULE_DESCRIPTION("Meson H/W Random Number Generator driver"); MODULE_AUTHOR("Lawrence Mok <lawrence.mok@amlogic.com>"); MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>"); MODULE_LICENSE("Dual BSD/GPL");