1 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause 2 /* 3 * Copyright (c) 2016 BayLibre, SAS. 4 * Author: Neil Armstrong <narmstrong@baylibre.com> 5 * Copyright (C) 2014 Amlogic, Inc. 6 */ 7 #include <linux/err.h> 8 #include <linux/module.h> 9 #include <linux/io.h> 10 #include <linux/platform_device.h> 11 #include <linux/hw_random.h> 12 #include <linux/slab.h> 13 #include <linux/types.h> 14 #include <linux/of.h> 15 #include <linux/clk.h> 16 17 #define RNG_DATA 0x00 18 19 struct meson_rng_data { 20 void __iomem *base; 21 struct hwrng rng; 22 }; 23 24 static int meson_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) 25 { 26 struct meson_rng_data *data = 27 container_of(rng, struct meson_rng_data, rng); 28 29 *(u32 *)buf = readl_relaxed(data->base + RNG_DATA); 30 31 return sizeof(u32); 32 } 33 34 static int meson_rng_probe(struct platform_device *pdev) 35 { 36 struct device *dev = &pdev->dev; 37 struct meson_rng_data *data; 38 struct clk *core_clk; 39 40 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); 41 if (!data) 42 return -ENOMEM; 43 44 data->base = devm_platform_ioremap_resource(pdev, 0); 45 if (IS_ERR(data->base)) 46 return PTR_ERR(data->base); 47 48 core_clk = devm_clk_get_optional_enabled(dev, "core"); 49 if (IS_ERR(core_clk)) 50 return dev_err_probe(dev, PTR_ERR(core_clk), 51 "Failed to get core clock\n"); 52 53 data->rng.name = pdev->name; 54 data->rng.read = meson_rng_read; 55 56 return devm_hwrng_register(dev, &data->rng); 57 } 58 59 static const struct of_device_id meson_rng_of_match[] = { 60 { .compatible = "amlogic,meson-rng", }, 61 {}, 62 }; 63 MODULE_DEVICE_TABLE(of, meson_rng_of_match); 64 65 static struct platform_driver meson_rng_driver = { 66 .probe = meson_rng_probe, 67 .driver = { 68 .name = "meson-rng", 69 .of_match_table = meson_rng_of_match, 70 }, 71 }; 72 73 module_platform_driver(meson_rng_driver); 74 75 MODULE_DESCRIPTION("Meson H/W Random Number Generator driver"); 76 MODULE_AUTHOR("Lawrence Mok <lawrence.mok@amlogic.com>"); 77 MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>"); 78 MODULE_LICENSE("Dual BSD/GPL"); 79