1 // SPDX-License-Identifier: GPL-2.0+
3 * Copyright (c) 2019, Linaro Limited
9 #include <virtio_types.h>
11 #include <virtio_ring.h>
13 #define BUFFER_SIZE 16UL
15 struct virtio_rng_priv {
16 struct virtqueue *rng_vq;
19 static int virtio_rng_read(struct udevice *dev, void *data, size_t len)
23 unsigned char buf[BUFFER_SIZE] __aligned(4);
24 unsigned char *ptr = data;
26 struct virtio_sg *sgs[1];
27 struct virtio_rng_priv *priv = dev_get_priv(dev);
31 sg.length = min(len, sizeof(buf));
34 ret = virtqueue_add(priv->rng_vq, sgs, 0, 1);
38 virtqueue_kick(priv->rng_vq);
40 while (!virtqueue_get_buf(priv->rng_vq, &rsize))
43 memcpy(ptr, buf, rsize);
51 static int virtio_rng_bind(struct udevice *dev)
53 struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(dev->parent);
55 /* Indicate what driver features we support */
56 virtio_driver_features_init(uc_priv, NULL, 0, NULL, 0);
61 static int virtio_rng_probe(struct udevice *dev)
63 struct virtio_rng_priv *priv = dev_get_priv(dev);
66 ret = virtio_find_vqs(dev, 1, &priv->rng_vq);
68 debug("%s: virtio_find_vqs failed\n", __func__);
75 static const struct dm_rng_ops virtio_rng_ops = {
76 .read = virtio_rng_read,
79 U_BOOT_DRIVER(virtio_rng) = {
80 .name = VIRTIO_RNG_DRV_NAME,
82 .bind = virtio_rng_bind,
83 .probe = virtio_rng_probe,
84 .remove = virtio_reset,
85 .ops = &virtio_rng_ops,
86 .priv_auto_alloc_size = sizeof(struct virtio_rng_priv),
87 .flags = DM_FLAG_ACTIVE_DMA,