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- // SPDX-License-Identifier: GPL-2.0+
- /*
- * Copyright (c) 2019, Linaro Limited
- */
- #include <common.h>
- #include <dm.h>
- #include <log.h>
- #include <rng.h>
- #include <virtio_types.h>
- #include <virtio.h>
- #include <virtio_ring.h>
- #define BUFFER_SIZE 16UL
- struct virtio_rng_priv {
- struct virtqueue *rng_vq;
- };
- static int virtio_rng_read(struct udevice *dev, void *data, size_t len)
- {
- int ret;
- unsigned int rsize;
- unsigned char buf[BUFFER_SIZE] __aligned(4);
- unsigned char *ptr = data;
- struct virtio_sg sg;
- struct virtio_sg *sgs[1];
- struct virtio_rng_priv *priv = dev_get_priv(dev);
- while (len) {
- sg.addr = buf;
- sg.length = min(len, sizeof(buf));
- sgs[0] = &sg;
- ret = virtqueue_add(priv->rng_vq, sgs, 0, 1);
- if (ret)
- return ret;
- virtqueue_kick(priv->rng_vq);
- while (!virtqueue_get_buf(priv->rng_vq, &rsize))
- ;
- memcpy(ptr, buf, rsize);
- len -= rsize;
- ptr += rsize;
- }
- return 0;
- }
- static int virtio_rng_bind(struct udevice *dev)
- {
- struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(dev->parent);
- /* Indicate what driver features we support */
- virtio_driver_features_init(uc_priv, NULL, 0, NULL, 0);
- return 0;
- }
- static int virtio_rng_probe(struct udevice *dev)
- {
- struct virtio_rng_priv *priv = dev_get_priv(dev);
- int ret;
- ret = virtio_find_vqs(dev, 1, &priv->rng_vq);
- if (ret < 0) {
- debug("%s: virtio_find_vqs failed\n", __func__);
- return ret;
- }
- return 0;
- }
- static const struct dm_rng_ops virtio_rng_ops = {
- .read = virtio_rng_read,
- };
- U_BOOT_DRIVER(virtio_rng) = {
- .name = VIRTIO_RNG_DRV_NAME,
- .id = UCLASS_RNG,
- .bind = virtio_rng_bind,
- .probe = virtio_rng_probe,
- .remove = virtio_reset,
- .ops = &virtio_rng_ops,
- .priv_auto = sizeof(struct virtio_rng_priv),
- .flags = DM_FLAG_ACTIVE_DMA,
- };
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