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 <log.h>
  8. #include <rng.h>
  9. #include <virtio_types.h>
  10. #include <virtio.h>
  11. #include <virtio_ring.h>
  12. #define BUFFER_SIZE 16UL
  13. struct virtio_rng_priv {
  14. struct virtqueue *rng_vq;
  15. };
  16. static int virtio_rng_read(struct udevice *dev, void *data, size_t len)
  17. {
  18. int ret;
  19. unsigned int rsize;
  20. unsigned char buf[BUFFER_SIZE] __aligned(4);
  21. unsigned char *ptr = data;
  22. struct virtio_sg sg;
  23. struct virtio_sg *sgs[1];
  24. struct virtio_rng_priv *priv = dev_get_priv(dev);
  25. while (len) {
  26. sg.addr = buf;
  27. sg.length = min(len, sizeof(buf));
  28. sgs[0] = &sg;
  29. ret = virtqueue_add(priv->rng_vq, sgs, 0, 1);
  30. if (ret)
  31. return ret;
  32. virtqueue_kick(priv->rng_vq);
  33. while (!virtqueue_get_buf(priv->rng_vq, &rsize))
  34. ;
  35. memcpy(ptr, buf, rsize);
  36. len -= rsize;
  37. ptr += rsize;
  38. }
  39. return 0;
  40. }
  41. static int virtio_rng_bind(struct udevice *dev)
  42. {
  43. struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(dev->parent);
  44. /* Indicate what driver features we support */
  45. virtio_driver_features_init(uc_priv, NULL, 0, NULL, 0);
  46. return 0;
  47. }
  48. static int virtio_rng_probe(struct udevice *dev)
  49. {
  50. struct virtio_rng_priv *priv = dev_get_priv(dev);
  51. int ret;
  52. ret = virtio_find_vqs(dev, 1, &priv->rng_vq);
  53. if (ret < 0) {
  54. debug("%s: virtio_find_vqs failed\n", __func__);
  55. return ret;
  56. }
  57. return 0;
  58. }
  59. static const struct dm_rng_ops virtio_rng_ops = {
  60. .read = virtio_rng_read,
  61. };
  62. U_BOOT_DRIVER(virtio_rng) = {
  63. .name = VIRTIO_RNG_DRV_NAME,
  64. .id = UCLASS_RNG,
  65. .bind = virtio_rng_bind,
  66. .probe = virtio_rng_probe,
  67. .remove = virtio_reset,
  68. .ops = &virtio_rng_ops,
  69. .priv_auto = sizeof(struct virtio_rng_priv),
  70. .flags = DM_FLAG_ACTIVE_DMA,
  71. };