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https://github.com/torvalds/linux
synced 2024-10-11 13:55:09 +00:00
virtio-rng: support multiple virtio-rng devices
Current hwrng core supports to register multiple hwrng devices, and there is only one device really works in the same time. QEMU alsu supports to have multiple virtio-rng backends. This patch changes virtio-rng driver to support multiple virtio-rng devices. ]# cat /sys/class/misc/hw_random/rng_available virtio_rng.0 virtio_rng.1 ]# cat /sys/class/misc/hw_random/rng_current virtio_rng.0 ]# echo -n virtio_rng.1 > /sys/class/misc/hw_random/rng_current ]# dd if=/dev/hwrng of=/dev/null Signed-off-by: Amos Kong <akong@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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@ -25,88 +25,108 @@
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#include <linux/virtio_rng.h>
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#include <linux/virtio_rng.h>
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#include <linux/module.h>
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#include <linux/module.h>
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static struct virtqueue *vq;
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static unsigned int data_avail;
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struct virtrng_info {
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static DECLARE_COMPLETION(have_data);
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struct virtio_device *vdev;
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static bool busy;
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struct hwrng hwrng;
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struct virtqueue *vq;
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unsigned int data_avail;
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struct completion have_data;
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bool busy;
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};
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static void random_recv_done(struct virtqueue *vq)
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static void random_recv_done(struct virtqueue *vq)
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{
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{
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struct virtrng_info *vi = vq->vdev->priv;
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/* We can get spurious callbacks, e.g. shared IRQs + virtio_pci. */
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/* We can get spurious callbacks, e.g. shared IRQs + virtio_pci. */
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if (!virtqueue_get_buf(vq, &data_avail))
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if (!virtqueue_get_buf(vi->vq, &vi->data_avail))
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return;
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return;
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complete(&have_data);
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complete(&vi->have_data);
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}
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}
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/* The host will fill any buffer we give it with sweet, sweet randomness. */
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/* The host will fill any buffer we give it with sweet, sweet randomness. */
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static void register_buffer(u8 *buf, size_t size)
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static void register_buffer(struct virtrng_info *vi, u8 *buf, size_t size)
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{
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{
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struct scatterlist sg;
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struct scatterlist sg;
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sg_init_one(&sg, buf, size);
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sg_init_one(&sg, buf, size);
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/* There should always be room for one buffer. */
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/* There should always be room for one buffer. */
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virtqueue_add_inbuf(vq, &sg, 1, buf, GFP_KERNEL);
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virtqueue_add_inbuf(vi->vq, &sg, 1, buf, GFP_KERNEL);
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virtqueue_kick(vq);
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virtqueue_kick(vi->vq);
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}
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}
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static int virtio_read(struct hwrng *rng, void *buf, size_t size, bool wait)
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static int virtio_read(struct hwrng *rng, void *buf, size_t size, bool wait)
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{
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{
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int ret;
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int ret;
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struct virtrng_info *vi = (struct virtrng_info *)rng->priv;
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if (!busy) {
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if (!vi->busy) {
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busy = true;
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vi->busy = true;
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init_completion(&have_data);
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init_completion(&vi->have_data);
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register_buffer(buf, size);
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register_buffer(vi, buf, size);
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}
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}
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if (!wait)
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if (!wait)
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return 0;
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return 0;
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ret = wait_for_completion_killable(&have_data);
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ret = wait_for_completion_killable(&vi->have_data);
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if (ret < 0)
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if (ret < 0)
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return ret;
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return ret;
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busy = false;
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vi->busy = false;
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return data_avail;
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return vi->data_avail;
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}
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}
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static void virtio_cleanup(struct hwrng *rng)
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static void virtio_cleanup(struct hwrng *rng)
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{
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{
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if (busy)
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struct virtrng_info *vi = (struct virtrng_info *)rng->priv;
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wait_for_completion(&have_data);
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if (vi->busy)
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wait_for_completion(&vi->have_data);
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}
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}
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static struct hwrng virtio_hwrng = {
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.name = "virtio",
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.cleanup = virtio_cleanup,
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.read = virtio_read,
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};
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static int probe_common(struct virtio_device *vdev)
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static int probe_common(struct virtio_device *vdev)
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{
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{
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int err;
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int err, i;
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struct virtrng_info *vi = NULL;
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vi = kmalloc(sizeof(struct virtrng_info), GFP_KERNEL);
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vi->hwrng.name = kmalloc(40, GFP_KERNEL);
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init_completion(&vi->have_data);
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vi->hwrng.read = virtio_read;
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vi->hwrng.cleanup = virtio_cleanup;
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vi->hwrng.priv = (unsigned long)vi;
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vdev->priv = vi;
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if (vq) {
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/* We only support one device for now */
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return -EBUSY;
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}
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/* We expect a single virtqueue. */
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/* We expect a single virtqueue. */
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vq = virtio_find_single_vq(vdev, random_recv_done, "input");
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vi->vq = virtio_find_single_vq(vdev, random_recv_done, "input");
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if (IS_ERR(vq)) {
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if (IS_ERR(vi->vq)) {
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err = PTR_ERR(vq);
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err = PTR_ERR(vi->vq);
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vq = NULL;
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kfree(vi->hwrng.name);
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vi->vq = NULL;
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kfree(vi);
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vi = NULL;
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return err;
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return err;
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}
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}
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err = hwrng_register(&virtio_hwrng);
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i = 0;
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do {
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sprintf(vi->hwrng.name, "virtio_rng.%d", i++);
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err = hwrng_register(&vi->hwrng);
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} while (err == -EEXIST);
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if (err) {
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if (err) {
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vdev->config->del_vqs(vdev);
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vdev->config->del_vqs(vdev);
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vq = NULL;
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kfree(vi->hwrng.name);
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vi->vq = NULL;
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kfree(vi);
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vi = NULL;
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return err;
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return err;
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}
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}
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@ -115,11 +135,15 @@ static int probe_common(struct virtio_device *vdev)
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static void remove_common(struct virtio_device *vdev)
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static void remove_common(struct virtio_device *vdev)
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{
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{
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struct virtrng_info *vi = vdev->priv;
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vdev->config->reset(vdev);
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vdev->config->reset(vdev);
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busy = false;
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vi->busy = false;
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hwrng_unregister(&virtio_hwrng);
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hwrng_unregister(&vi->hwrng);
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vdev->config->del_vqs(vdev);
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vdev->config->del_vqs(vdev);
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vq = NULL;
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kfree(vi->hwrng.name);
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vi->vq = NULL;
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kfree(vi);
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vi = NULL;
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}
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}
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static int virtrng_probe(struct virtio_device *vdev)
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static int virtrng_probe(struct virtio_device *vdev)
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@ -31,7 +31,7 @@
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* @priv: Private data, for use by the RNG driver.
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* @priv: Private data, for use by the RNG driver.
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*/
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*/
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struct hwrng {
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struct hwrng {
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const char *name;
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char *name;
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int (*init)(struct hwrng *rng);
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int (*init)(struct hwrng *rng);
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void (*cleanup)(struct hwrng *rng);
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void (*cleanup)(struct hwrng *rng);
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int (*data_present)(struct hwrng *rng, int wait);
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int (*data_present)(struct hwrng *rng, int wait);
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