sandbox_rng.c 1014 B

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