virtio_rng.c
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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (c) 2019, Linaro Limited
*/
#include <common.h>
#include <dm.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_alloc_size = sizeof(struct virtio_rng_priv),
.flags = DM_FLAG_ACTIVE_DMA,
};