virtio_rng.c 1.7 KB

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  1. // SPDX-License-Identifier: GPL-2.0+
  2. /*
  3. * Copyright (c) 2019, Linaro Limited
  4. */
  5. #include <common.h>
  6. #include <dm.h>
  7. #include <rng.h>
  8. #include <virtio_types.h>
  9. #include <virtio.h>
  10. #include <virtio_ring.h>
  11. #define BUFFER_SIZE 16UL
  12. struct virtio_rng_priv {
  13. struct virtqueue *rng_vq;
  14. };
  15. static int virtio_rng_read(struct udevice *dev, void *data, size_t len)
  16. {
  17. int ret;
  18. unsigned int rsize;
  19. unsigned char buf[BUFFER_SIZE] __aligned(4);
  20. unsigned char *ptr = data;
  21. struct virtio_sg sg;
  22. struct virtio_sg *sgs[1];
  23. struct virtio_rng_priv *priv = dev_get_priv(dev);
  24. while (len) {
  25. sg.addr = buf;
  26. sg.length = min(len, sizeof(buf));
  27. sgs[0] = &sg;
  28. ret = virtqueue_add(priv->rng_vq, sgs, 0, 1);
  29. if (ret)
  30. return ret;
  31. virtqueue_kick(priv->rng_vq);
  32. while (!virtqueue_get_buf(priv->rng_vq, &rsize))
  33. ;
  34. memcpy(ptr, buf, rsize);
  35. len -= rsize;
  36. ptr += rsize;
  37. }
  38. return 0;
  39. }
  40. static int virtio_rng_bind(struct udevice *dev)
  41. {
  42. struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(dev->parent);
  43. /* Indicate what driver features we support */
  44. virtio_driver_features_init(uc_priv, NULL, 0, NULL, 0);
  45. return 0;
  46. }
  47. static int virtio_rng_probe(struct udevice *dev)
  48. {
  49. struct virtio_rng_priv *priv = dev_get_priv(dev);
  50. int ret;
  51. ret = virtio_find_vqs(dev, 1, &priv->rng_vq);
  52. if (ret < 0) {
  53. debug("%s: virtio_find_vqs failed\n", __func__);
  54. return ret;
  55. }
  56. return 0;
  57. }
  58. static const struct dm_rng_ops virtio_rng_ops = {
  59. .read = virtio_rng_read,
  60. };
  61. U_BOOT_DRIVER(virtio_rng) = {
  62. .name = VIRTIO_RNG_DRV_NAME,
  63. .id = UCLASS_RNG,
  64. .bind = virtio_rng_bind,
  65. .probe = virtio_rng_probe,
  66. .remove = virtio_reset,
  67. .ops = &virtio_rng_ops,
  68. .priv_auto_alloc_size = sizeof(struct virtio_rng_priv),
  69. .flags = DM_FLAG_ACTIVE_DMA,
  70. };