1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * drivers/char/hw_random/ixp4xx-rng.c 4 * 5 * RNG driver for Intel IXP4xx family of NPUs 6 * 7 * Author: Deepak Saxena <dsaxena@plexity.net> 8 * 9 * Copyright 2005 (c) MontaVista Software, Inc. 10 * 11 * Fixes by Michael Buesch 12 */ 13 14 #include <linux/kernel.h> 15 #include <linux/types.h> 16 #include <linux/module.h> 17 #include <linux/moduleparam.h> 18 #include <linux/platform_device.h> 19 #include <linux/init.h> 20 #include <linux/bitops.h> 21 #include <linux/hw_random.h> 22 #include <linux/of.h> 23 #include <linux/soc/ixp4xx/cpu.h> 24 25 #include <asm/io.h> 26 27 static int ixp4xx_rng_data_read(struct hwrng *rng, u32 *buffer) 28 { 29 void __iomem * rng_base = (void __iomem *)rng->priv; 30 31 *buffer = __raw_readl(rng_base); 32 33 return 4; 34 } 35 36 static struct hwrng ixp4xx_rng_ops = { 37 .name = "ixp4xx", 38 .data_read = ixp4xx_rng_data_read, 39 }; 40 41 static int ixp4xx_rng_probe(struct platform_device *pdev) 42 { 43 void __iomem * rng_base; 44 struct device *dev = &pdev->dev; 45 46 if (!cpu_is_ixp46x()) /* includes IXP455 */ 47 return -ENOSYS; 48 49 rng_base = devm_platform_ioremap_resource(pdev, 0); 50 if (IS_ERR(rng_base)) 51 return PTR_ERR(rng_base); 52 53 ixp4xx_rng_ops.priv = (unsigned long)rng_base; 54 return devm_hwrng_register(dev, &ixp4xx_rng_ops); 55 } 56 57 static const struct of_device_id ixp4xx_rng_of_match[] = { 58 { 59 .compatible = "intel,ixp46x-rng", 60 }, 61 {}, 62 }; 63 MODULE_DEVICE_TABLE(of, ixp4xx_rng_of_match); 64 65 static struct platform_driver ixp4xx_rng_driver = { 66 .driver = { 67 .name = "ixp4xx-hwrandom", 68 .of_match_table = ixp4xx_rng_of_match, 69 }, 70 .probe = ixp4xx_rng_probe, 71 }; 72 module_platform_driver(ixp4xx_rng_driver); 73 74 MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>"); 75 MODULE_DESCRIPTION("H/W Pseudo-Random Number Generator (RNG) driver for IXP45x/46x"); 76 MODULE_LICENSE("GPL"); 77