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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crypto4xx_trng.c (3084B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * Generic PowerPC 44x RNG driver
      4 *
      5 * Copyright 2011 IBM Corporation
      6 */
      7
      8#include <linux/module.h>
      9#include <linux/kernel.h>
     10#include <linux/interrupt.h>
     11#include <linux/platform_device.h>
     12#include <linux/hw_random.h>
     13#include <linux/delay.h>
     14#include <linux/of_address.h>
     15#include <linux/of_platform.h>
     16#include <linux/io.h>
     17
     18#include "crypto4xx_core.h"
     19#include "crypto4xx_trng.h"
     20#include "crypto4xx_reg_def.h"
     21
     22#define PPC4XX_TRNG_CTRL	0x0008
     23#define PPC4XX_TRNG_CTRL_DALM	0x20
     24#define PPC4XX_TRNG_STAT	0x0004
     25#define PPC4XX_TRNG_STAT_B	0x1
     26#define PPC4XX_TRNG_DATA	0x0000
     27
     28static int ppc4xx_trng_data_present(struct hwrng *rng, int wait)
     29{
     30	struct crypto4xx_device *dev = (void *)rng->priv;
     31	int busy, i, present = 0;
     32
     33	for (i = 0; i < 20; i++) {
     34		busy = (in_le32(dev->trng_base + PPC4XX_TRNG_STAT) &
     35			PPC4XX_TRNG_STAT_B);
     36		if (!busy || !wait) {
     37			present = 1;
     38			break;
     39		}
     40		udelay(10);
     41	}
     42	return present;
     43}
     44
     45static int ppc4xx_trng_data_read(struct hwrng *rng, u32 *data)
     46{
     47	struct crypto4xx_device *dev = (void *)rng->priv;
     48	*data = in_le32(dev->trng_base + PPC4XX_TRNG_DATA);
     49	return 4;
     50}
     51
     52static void ppc4xx_trng_enable(struct crypto4xx_device *dev, bool enable)
     53{
     54	u32 device_ctrl;
     55
     56	device_ctrl = readl(dev->ce_base + CRYPTO4XX_DEVICE_CTRL);
     57	if (enable)
     58		device_ctrl |= PPC4XX_TRNG_EN;
     59	else
     60		device_ctrl &= ~PPC4XX_TRNG_EN;
     61	writel(device_ctrl, dev->ce_base + CRYPTO4XX_DEVICE_CTRL);
     62}
     63
     64static const struct of_device_id ppc4xx_trng_match[] = {
     65	{ .compatible = "ppc4xx-rng", },
     66	{ .compatible = "amcc,ppc460ex-rng", },
     67	{ .compatible = "amcc,ppc440epx-rng", },
     68	{},
     69};
     70
     71void ppc4xx_trng_probe(struct crypto4xx_core_device *core_dev)
     72{
     73	struct crypto4xx_device *dev = core_dev->dev;
     74	struct device_node *trng = NULL;
     75	struct hwrng *rng = NULL;
     76	int err;
     77
     78	/* Find the TRNG device node and map it */
     79	trng = of_find_matching_node(NULL, ppc4xx_trng_match);
     80	if (!trng || !of_device_is_available(trng)) {
     81		of_node_put(trng);
     82		return;
     83	}
     84
     85	dev->trng_base = of_iomap(trng, 0);
     86	of_node_put(trng);
     87	if (!dev->trng_base)
     88		goto err_out;
     89
     90	rng = kzalloc(sizeof(*rng), GFP_KERNEL);
     91	if (!rng)
     92		goto err_out;
     93
     94	rng->name = KBUILD_MODNAME;
     95	rng->data_present = ppc4xx_trng_data_present;
     96	rng->data_read = ppc4xx_trng_data_read;
     97	rng->priv = (unsigned long) dev;
     98	core_dev->trng = rng;
     99	ppc4xx_trng_enable(dev, true);
    100	out_le32(dev->trng_base + PPC4XX_TRNG_CTRL, PPC4XX_TRNG_CTRL_DALM);
    101	err = devm_hwrng_register(core_dev->device, core_dev->trng);
    102	if (err) {
    103		ppc4xx_trng_enable(dev, false);
    104		dev_err(core_dev->device, "failed to register hwrng (%d).\n",
    105			err);
    106		goto err_out;
    107	}
    108	return;
    109
    110err_out:
    111	iounmap(dev->trng_base);
    112	kfree(rng);
    113	dev->trng_base = NULL;
    114	core_dev->trng = NULL;
    115}
    116
    117void ppc4xx_trng_remove(struct crypto4xx_core_device *core_dev)
    118{
    119	if (core_dev && core_dev->trng) {
    120		struct crypto4xx_device *dev = core_dev->dev;
    121
    122		devm_hwrng_unregister(core_dev->device, core_dev->trng);
    123		ppc4xx_trng_enable(dev, false);
    124		iounmap(dev->trng_base);
    125		kfree(core_dev->trng);
    126	}
    127}
    128
    129MODULE_ALIAS("ppc4xx_rng");