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drivers: entropy: virtio: use bounce buffer for virtio entropy driver

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The device is not able to place the entropy into stack or heap allocated
buffers. This uses a bounce buffer to be able to use any buffer with
virtio entropy.

Signed-off-by: Juliusz Sosinowicz <juliusz@wolfssl.com>
This commit is contained in:
Juliusz Sosinowicz
2025-12-16 18:44:23 +01:00
committed by Chris Friedt
parent d334130d5d
commit 3f04069069
1 changed files with 31 additions and 12 deletions
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43
drivers/entropy/entropy_virtio.c
View File

@@ -19,9 +19,13 @@ struct entropy_virtio_config {
const struct device *vdev;
};
#define ENTROPY_BUFFER_MAX_LEN 256
struct entropy_virtio_data {
struct k_sem sem;
uint32_t received_len;
struct k_mutex buf_mutex;
uint8_t buf[ENTROPY_BUFFER_MAX_LEN];
};
static void entropy_virtio_virtq_recv_cb(void *priv, uint32_t len)
@@ -43,7 +47,6 @@ static uint16_t entropy_virtio_enum_queues_cb(uint16_t q_index, uint16_t q_size_
static int entropy_virtio_get_entropy(const struct device *dev, uint8_t *buffer, uint16_t length)
{
struct virtq_buf buf[] = {{.addr = buffer, .len = length}};
const struct entropy_virtio_config *cfg = dev->config;
struct entropy_virtio_data *data = dev->data;
struct virtq *vq = virtio_get_virtqueue(cfg->vdev, VIRTIO_ENTROPY_QUEUE_IDX);
@@ -54,20 +57,35 @@ static int entropy_virtio_get_entropy(const struct device *dev, uint8_t *buffer,
return -ENODEV;
}
data->received_len = 0;
ret = virtq_add_buffer_chain(vq, buf, 1, 0, entropy_virtio_virtq_recv_cb, data, K_FOREVER);
if (ret) {
LOG_ERR("virtq_add_buffer_chain failed: %d", ret);
return -EIO;
}
while (length > 0) {
struct virtq_buf buf[] = {
{.addr = data->buf, .len = MIN(length, ENTROPY_BUFFER_MAX_LEN)}};
virtio_notify_virtqueue(cfg->vdev, VIRTIO_ENTROPY_QUEUE_IDX);
k_mutex_lock(&data->buf_mutex, K_FOREVER);
data->received_len = 0;
ret = virtq_add_buffer_chain(vq, buf, 1, 0, entropy_virtio_virtq_recv_cb, data,
K_FOREVER);
if (ret) {
LOG_ERR("virtq_add_buffer_chain failed: %d", ret);
k_mutex_unlock(&data->buf_mutex);
return -EIO;
}
k_sem_take(&data->sem, K_FOREVER);
virtio_notify_virtqueue(cfg->vdev, VIRTIO_ENTROPY_QUEUE_IDX);
if (data->received_len != length) {
LOG_ERR("insufficient number of values: %d/%d", data->received_len, length);
return -EIO;
k_sem_take(&data->sem, K_FOREVER);
if (data->received_len != buf[0].len) {
LOG_ERR("insufficient number of values: %d/%d", data->received_len,
buf[0].len);
k_mutex_unlock(&data->buf_mutex);
return -EIO;
}
memcpy(buffer, data->buf, data->received_len);
buffer += data->received_len;
length -= data->received_len;
k_mutex_unlock(&data->buf_mutex);
}
return 0;
@@ -97,6 +115,7 @@ static int entropy_virtio_init(const struct device *dev)
virtio_finalize_init(cfg->vdev);
k_sem_init(&data->sem, 0, 1);
k_mutex_init(&data->buf_mutex);
LOG_DBG("virtio entropy driver initialized");
return 0;