diff options
Diffstat (limited to 'sys/dev/virtio/random/virtio_random.c')
| -rw-r--r-- | sys/dev/virtio/random/virtio_random.c | 231 |
1 files changed, 231 insertions, 0 deletions
diff --git a/sys/dev/virtio/random/virtio_random.c b/sys/dev/virtio/random/virtio_random.c new file mode 100644 index 000000000000..f44878f21897 --- /dev/null +++ b/sys/dev/virtio/random/virtio_random.c @@ -0,0 +1,231 @@ +/*- + * Copyright (c) 2013, Bryan Venteicher <bryanv@FreeBSD.org> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice unmodified, this list of conditions, and the following + * disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +/* Driver for VirtIO entropy device. */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include <sys/param.h> +#include <sys/kernel.h> +#include <sys/module.h> +#include <sys/sglist.h> +#include <sys/callout.h> +#include <sys/random.h> + +#include <machine/bus.h> +#include <machine/resource.h> +#include <sys/bus.h> + +#include <dev/virtio/virtio.h> +#include <dev/virtio/virtqueue.h> + +struct vtrnd_softc { + device_t vtrnd_dev; + uint64_t vtrnd_features; + struct callout vtrnd_callout; + struct virtqueue *vtrnd_vq; +}; + +static int vtrnd_modevent(module_t, int, void *); + +static int vtrnd_probe(device_t); +static int vtrnd_attach(device_t); +static int vtrnd_detach(device_t); + +static void vtrnd_negotiate_features(struct vtrnd_softc *); +static int vtrnd_alloc_virtqueue(struct vtrnd_softc *); +static void vtrnd_harvest(struct vtrnd_softc *); +static void vtrnd_timer(void *); + +#define VTRND_FEATURES 0 + +static struct virtio_feature_desc vtrnd_feature_desc[] = { + { 0, NULL } +}; + +static device_method_t vtrnd_methods[] = { + /* Device methods. */ + DEVMETHOD(device_probe, vtrnd_probe), + DEVMETHOD(device_attach, vtrnd_attach), + DEVMETHOD(device_detach, vtrnd_detach), + + DEVMETHOD_END +}; + +static driver_t vtrnd_driver = { + "vtrnd", + vtrnd_methods, + sizeof(struct vtrnd_softc) +}; +static devclass_t vtrnd_devclass; + +DRIVER_MODULE(virtio_random, virtio_pci, vtrnd_driver, vtrnd_devclass, + vtrnd_modevent, 0); +MODULE_VERSION(virtio_random, 1); +MODULE_DEPEND(virtio_random, virtio, 1, 1, 1); + +static int +vtrnd_modevent(module_t mod, int type, void *unused) +{ + int error; + + switch (type) { + case MOD_LOAD: + case MOD_QUIESCE: + case MOD_UNLOAD: + case MOD_SHUTDOWN: + error = 0; + break; + default: + error = EOPNOTSUPP; + break; + } + + return (error); +} + +static int +vtrnd_probe(device_t dev) +{ + + if (virtio_get_device_type(dev) != VIRTIO_ID_ENTROPY) + return (ENXIO); + + device_set_desc(dev, "VirtIO Entropy Adapter"); + + return (BUS_PROBE_DEFAULT); +} + +static int +vtrnd_attach(device_t dev) +{ + struct vtrnd_softc *sc; + int error; + + sc = device_get_softc(dev); + sc->vtrnd_dev = dev; + + callout_init(&sc->vtrnd_callout, CALLOUT_MPSAFE); + + virtio_set_feature_desc(dev, vtrnd_feature_desc); + vtrnd_negotiate_features(sc); + + error = vtrnd_alloc_virtqueue(sc); + if (error) { + device_printf(dev, "cannot allocate virtqueue\n"); + goto fail; + } + + callout_reset(&sc->vtrnd_callout, 5 * hz, vtrnd_timer, sc); + +fail: + if (error) + vtrnd_detach(dev); + + return (error); +} + +static int +vtrnd_detach(device_t dev) +{ + struct vtrnd_softc *sc; + + sc = device_get_softc(dev); + + callout_stop(&sc->vtrnd_callout); + + return (0); +} + +static void +vtrnd_negotiate_features(struct vtrnd_softc *sc) +{ + device_t dev; + uint64_t features; + + dev = sc->vtrnd_dev; + features = VTRND_FEATURES; + + sc->vtrnd_features = virtio_negotiate_features(dev, features); +} + +static int +vtrnd_alloc_virtqueue(struct vtrnd_softc *sc) +{ + device_t dev; + struct vq_alloc_info vq_info; + + dev = sc->vtrnd_dev; + + VQ_ALLOC_INFO_INIT(&vq_info, 0, NULL, sc, &sc->vtrnd_vq, + "%s request", device_get_nameunit(dev)); + + return (virtio_alloc_virtqueues(dev, 0, 1, &vq_info)); +} + +static void +vtrnd_harvest(struct vtrnd_softc *sc) +{ + struct sglist_seg segs[1]; + struct sglist sg; + struct virtqueue *vq; + uint32_t value; + int error; + + vq = sc->vtrnd_vq; + + sglist_init(&sg, 1, segs); + error = sglist_append(&sg, &value, sizeof(value)); + KASSERT(error == 0 && sg.sg_nseg == 1, + ("%s: error %d adding buffer to sglist", __func__, error)); + + if (!virtqueue_empty(vq)) + return; + if (virtqueue_enqueue(vq, &value, &sg, 0, 1) != 0) + return; + + /* + * Poll for the response, but the command is likely already + * done when we return from the notify. + */ + virtqueue_notify(vq); + virtqueue_poll(vq, NULL); + + random_harvest(&value, sizeof(value), sizeof(value) * NBBY / 2, + RANDOM_PURE_VIRTIO); +} + +static void +vtrnd_timer(void *xsc) +{ + struct vtrnd_softc *sc; + + sc = xsc; + + vtrnd_harvest(sc); + callout_schedule(&sc->vtrnd_callout, 5 * hz); +} |