cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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ixp4xx-rng.c (1758B)

      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
     27static 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
     36static struct hwrng ixp4xx_rng_ops = {
     37	.name		= "ixp4xx",
     38	.data_read	= ixp4xx_rng_data_read,
     39};
     40
     41static 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
     57static const struct of_device_id ixp4xx_rng_of_match[] = {
     58	{
     59		.compatible = "intel,ixp46x-rng",
     60	},
     61	{},
     62};
     63MODULE_DEVICE_TABLE(of, ixp4xx_rng_of_match);
     64
     65static 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};
     72module_platform_driver(ixp4xx_rng_driver);
     73
     74MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
     75MODULE_DESCRIPTION("H/W Pseudo-Random Number Generator (RNG) driver for IXP45x/46x");
     76MODULE_LICENSE("GPL");