LXR uboot/drivers/rng/sandbox

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Copyright (c) 2019, Linaro Limited
   4 */
   5
   6#include <common.h>
   7#include <dm.h>
   8#include <rand.h>
   9#include <rng.h>
  10
  11#include <linux/string.h>
  12
  13static int sandbox_rng_read(struct udevice *dev, void *data, size_t len)
  14{
  15        unsigned int i, seed, random;
  16        unsigned char *buf = data;
  17        size_t nrem, nloops;
  18
  19        if (!len)
  20                return 0;
  21
  22        nloops = len / sizeof(random);
  23        seed = get_timer(0) ^ rand();
  24        srand(seed);
  25
  26        for (i = 0, nrem = len; i < nloops; i++) {
  27                random = rand();
  28                memcpy(buf, &random, sizeof(random));
  29                buf += sizeof(random);
  30                nrem -= sizeof(random);
  31        }
  32
  33        if (nrem) {
  34                random = rand();
  35                memcpy(buf, &random, nrem);
  36        }
  37
  38        return 0;
  39}
  40
  41static const struct dm_rng_ops sandbox_rng_ops = {
  42        .read = sandbox_rng_read,
  43};
  44
  45static const struct udevice_id sandbox_rng_match[] = {
  46        {
  47                .compatible = "sandbox,sandbox-rng",
  48        },
  49        {},
  50};
  51
  52U_BOOT_DRIVER(sandbox_rng) = {
  53        .name = "sandbox-rng",
  54        .id = UCLASS_RNG,
  55        .of_match = sandbox_rng_match,
  56        .ops = &sandbox_rng_ops,
  57};
  58