git: e1c4c8dd8d2d - main - vtscmi: Add a virtio-scmi driver
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Date: Thu, 11 Apr 2024 09:59:30 UTC
The branch main has been updated by andrew:
URL: https://cgit.FreeBSD.org/src/commit/?id=e1c4c8dd8d2d10b6104f06856a77bd5b4813a801
commit e1c4c8dd8d2d10b6104f06856a77bd5b4813a801
Author: Cristian Marussi <cristian.marussi@arm.com>
AuthorDate: 2023-10-20 13:17:38 +0000
Commit: Andrew Turner <andrew@FreeBSD.org>
CommitDate: 2024-04-11 09:58:56 +0000
vtscmi: Add a virtio-scmi driver
Add a new virtio backend to support SCMI VirtIO devices (type 32) as
defined by the VirtIO specification since version v1.2.
https://docs.oasis-open.org/virtio/virtio/v1.2/cs01/virtio-v1.2-cs01.pdf
Reviewed by: andrew, bryanv
Sponsored by: Arm Ltd
Differential Revision: https://reviews.freebsd.org/D43047
---
sys/arm64/conf/NOTES | 1 +
sys/arm64/conf/std.virt | 1 +
sys/conf/files | 1 +
sys/dev/virtio/scmi/virtio_scmi.c | 520 ++++++++++++++++++++++++++++++++++++++
sys/dev/virtio/scmi/virtio_scmi.h | 66 +++++
sys/dev/virtio/virtio.c | 1 +
sys/dev/virtio/virtio_ids.h | 1 +
7 files changed, 591 insertions(+)
diff --git a/sys/arm64/conf/NOTES b/sys/arm64/conf/NOTES
index 91455d6032b9..128fb80b95d4 100644
--- a/sys/arm64/conf/NOTES
+++ b/sys/arm64/conf/NOTES
@@ -66,6 +66,7 @@ device virtio_pci
device virtio_mmio
device virtio_blk
device vtnet
+device virtio_scmi
# Google Virtual NIC
device gve # Google Virtual NIC (gVNIC) driver
diff --git a/sys/arm64/conf/std.virt b/sys/arm64/conf/std.virt
index 5047aabac42c..8e64ce44f89b 100644
--- a/sys/arm64/conf/std.virt
+++ b/sys/arm64/conf/std.virt
@@ -20,6 +20,7 @@ device virtio_pci # VirtIO PCI device
device virtio_mmio # VirtIO Memory Mapped IO device
device virtio_blk # VirtIO Block device
device virtio_gpu # VirtIO GPU device
+device virtio_scmi # VirtIO SCMI device
device virtio_scsi # VirtIO SCSI device
device vtnet # VirtIO Ethernet device
diff --git a/sys/conf/files b/sys/conf/files
index 68f8060e61ad..2c262e36eeb0 100644
--- a/sys/conf/files
+++ b/sys/conf/files
@@ -3422,6 +3422,7 @@ dev/virtio/gpu/virtio_gpu.c optional virtio_gpu
dev/virtio/scsi/virtio_scsi.c optional virtio_scsi
dev/virtio/random/virtio_random.c optional virtio_random
dev/virtio/console/virtio_console.c optional virtio_console
+dev/virtio/scmi/virtio_scmi.c optional virtio_scmi
dev/vkbd/vkbd.c optional vkbd
dev/vmgenc/vmgenc_acpi.c optional acpi
dev/vmware/vmxnet3/if_vmx.c optional vmx
diff --git a/sys/dev/virtio/scmi/virtio_scmi.c b/sys/dev/virtio/scmi/virtio_scmi.c
new file mode 100644
index 000000000000..f5427756e971
--- /dev/null
+++ b/sys/dev/virtio/scmi/virtio_scmi.c
@@ -0,0 +1,520 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2023 Arm Ltd
+ *
+ * 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 SCMI device. */
+
+#include <sys/cdefs.h>
+#include <sys/param.h>
+#include <sys/types.h>
+#include <sys/eventhandler.h>
+#include <sys/kernel.h>
+#include <sys/malloc.h>
+#include <sys/module.h>
+#include <sys/queue.h>
+#include <sys/sglist.h>
+
+#include <machine/bus.h>
+#include <machine/resource.h>
+#include <sys/bus.h>
+
+#include <dev/virtio/virtio.h>
+#include <dev/virtio/virtqueue.h>
+#include <dev/virtio/scmi/virtio_scmi.h>
+
+struct vtscmi_pdu {
+ enum vtscmi_chan chan;
+ struct sglist sg;
+ struct sglist_seg segs[2];
+ void *buf;
+ SLIST_ENTRY(vtscmi_pdu) next;
+};
+
+struct vtscmi_queue {
+ device_t dev;
+ int vq_id;
+ unsigned int vq_sz;
+ struct virtqueue *vq;
+ struct mtx vq_mtx;
+ struct vtscmi_pdu *pdus;
+ SLIST_HEAD(pdus_head, vtscmi_pdu) p_head;
+ struct mtx p_mtx;
+ virtio_scmi_rx_callback_t *rx_callback;
+ void *priv;
+};
+
+struct vtscmi_softc {
+ device_t vtscmi_dev;
+ uint64_t vtscmi_features;
+ uint8_t vtscmi_vqs_cnt;
+ struct vtscmi_queue vtscmi_queues[VIRTIO_SCMI_CHAN_MAX];
+ bool has_p2a;
+ bool has_shared;
+};
+
+static device_t vtscmi_dev;
+
+static int vtscmi_modevent(module_t, int, void *);
+
+static int vtscmi_probe(device_t);
+static int vtscmi_attach(device_t);
+static int vtscmi_detach(device_t);
+static int vtscmi_shutdown(device_t);
+static int vtscmi_negotiate_features(struct vtscmi_softc *);
+static int vtscmi_setup_features(struct vtscmi_softc *);
+static void vtscmi_vq_intr(void *);
+static int vtscmi_alloc_virtqueues(struct vtscmi_softc *);
+static int vtscmi_alloc_queues(struct vtscmi_softc *);
+static void vtscmi_free_queues(struct vtscmi_softc *);
+static void *virtio_scmi_pdu_get(struct vtscmi_queue *, void *,
+ unsigned int, unsigned int);
+static void virtio_scmi_pdu_put(device_t, struct vtscmi_pdu *);
+
+static struct virtio_feature_desc vtscmi_feature_desc[] = {
+ { VIRTIO_SCMI_F_P2A_CHANNELS, "P2AChannel" },
+ { VIRTIO_SCMI_F_SHARED_MEMORY, "SharedMem" },
+ { 0, NULL }
+};
+
+static device_method_t vtscmi_methods[] = {
+ /* Device methods. */
+ DEVMETHOD(device_probe, vtscmi_probe),
+ DEVMETHOD(device_attach, vtscmi_attach),
+ DEVMETHOD(device_detach, vtscmi_detach),
+ DEVMETHOD(device_shutdown, vtscmi_shutdown),
+
+ DEVMETHOD_END
+};
+
+static driver_t vtscmi_driver = {
+ "vtscmi",
+ vtscmi_methods,
+ sizeof(struct vtscmi_softc)
+};
+
+VIRTIO_DRIVER_MODULE(virtio_scmi, vtscmi_driver, vtscmi_modevent, NULL);
+MODULE_VERSION(virtio_scmi, 1);
+MODULE_DEPEND(virtio_scmi, virtio, 1, 1, 1);
+
+VIRTIO_SIMPLE_PNPINFO(virtio_scmi, VIRTIO_ID_SCMI, "VirtIO SCMI Adapter");
+
+static int
+vtscmi_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
+vtscmi_probe(device_t dev)
+{
+ return (VIRTIO_SIMPLE_PROBE(dev, virtio_scmi));
+}
+
+static int
+vtscmi_attach(device_t dev)
+{
+ struct vtscmi_softc *sc;
+ int error;
+
+ /* Only one SCMI device per-agent */
+ if (vtscmi_dev != NULL)
+ return (EEXIST);
+
+ sc = device_get_softc(dev);
+ sc->vtscmi_dev = dev;
+
+ virtio_set_feature_desc(dev, vtscmi_feature_desc);
+ error = vtscmi_setup_features(sc);
+ if (error) {
+ device_printf(dev, "cannot setup features\n");
+ goto fail;
+ }
+
+ error = vtscmi_alloc_virtqueues(sc);
+ if (error) {
+ device_printf(dev, "cannot allocate virtqueues\n");
+ goto fail;
+ }
+
+ error = vtscmi_alloc_queues(sc);
+ if (error) {
+ device_printf(dev, "cannot allocate queues\n");
+ goto fail;
+ }
+
+ error = virtio_setup_intr(dev, INTR_TYPE_MISC);
+ if (error) {
+ device_printf(dev, "cannot setup intr\n");
+ vtscmi_free_queues(sc);
+ goto fail;
+ }
+
+ /* Save unique device */
+ vtscmi_dev = sc->vtscmi_dev;
+
+fail:
+
+ return (error);
+}
+
+static int
+vtscmi_detach(device_t dev)
+{
+ struct vtscmi_softc *sc;
+
+ sc = device_get_softc(dev);
+
+ /* These also disable related interrupts */
+ virtio_scmi_channel_callback_set(dev, VIRTIO_SCMI_CHAN_A2P, NULL, NULL);
+ virtio_scmi_channel_callback_set(dev, VIRTIO_SCMI_CHAN_P2A, NULL, NULL);
+
+ virtio_stop(dev);
+
+ vtscmi_free_queues(sc);
+
+ return (0);
+}
+
+static int
+vtscmi_shutdown(device_t dev)
+{
+
+ return (0);
+}
+
+static int
+vtscmi_negotiate_features(struct vtscmi_softc *sc)
+{
+ device_t dev;
+ uint64_t features;
+
+ dev = sc->vtscmi_dev;
+ /* We still don't support shared mem (stats)...so don't advertise it */
+ features = VIRTIO_SCMI_F_P2A_CHANNELS;
+
+ sc->vtscmi_features = virtio_negotiate_features(dev, features);
+ return (virtio_finalize_features(dev));
+}
+
+static int
+vtscmi_setup_features(struct vtscmi_softc *sc)
+{
+ device_t dev;
+ int error;
+
+ dev = sc->vtscmi_dev;
+ error = vtscmi_negotiate_features(sc);
+ if (error)
+ return (error);
+
+ if (virtio_with_feature(dev, VIRTIO_SCMI_F_P2A_CHANNELS))
+ sc->has_p2a = true;
+ if (virtio_with_feature(dev, VIRTIO_SCMI_F_SHARED_MEMORY))
+ sc->has_shared = true;
+
+ device_printf(dev, "Platform %s P2A channel.\n",
+ sc->has_p2a ? "supports" : "does NOT support");
+
+ return (0);
+}
+
+static int
+vtscmi_alloc_queues(struct vtscmi_softc *sc)
+{
+ int idx;
+
+ for (idx = VIRTIO_SCMI_CHAN_A2P; idx < VIRTIO_SCMI_CHAN_MAX; idx++) {
+ int i, vq_sz;
+ struct vtscmi_queue *q;
+ struct vtscmi_pdu *pdu;
+
+ if (idx == VIRTIO_SCMI_CHAN_P2A && !sc->has_p2a)
+ continue;
+
+ q = &sc->vtscmi_queues[idx];
+ q->dev = sc->vtscmi_dev;
+ q->vq_id = idx;
+ vq_sz = virtqueue_size(q->vq);
+ q->vq_sz = idx != VIRTIO_SCMI_CHAN_A2P ? vq_sz : vq_sz / 2;
+
+ q->pdus = mallocarray(q->vq_sz, sizeof(*pdu), M_DEVBUF,
+ M_ZERO | M_WAITOK);
+
+ SLIST_INIT(&q->p_head);
+ for (i = 0, pdu = q->pdus; i < q->vq_sz; i++, pdu++) {
+ pdu->chan = idx;
+ //XXX Maybe one seg redndant for P2A
+ sglist_init(&pdu->sg,
+ idx == VIRTIO_SCMI_CHAN_A2P ? 2 : 1, pdu->segs);
+ SLIST_INSERT_HEAD(&q->p_head, pdu, next);
+ }
+
+ mtx_init(&q->p_mtx, "vtscmi_pdus", "VTSCMI", MTX_SPIN);
+ mtx_init(&q->vq_mtx, "vtscmi_vq", "VTSCMI", MTX_SPIN);
+ }
+
+ return (0);
+}
+
+static void
+vtscmi_free_queues(struct vtscmi_softc *sc)
+{
+ int idx;
+
+ for (idx = VIRTIO_SCMI_CHAN_A2P; idx < VIRTIO_SCMI_CHAN_MAX; idx++) {
+ struct vtscmi_queue *q;
+
+ if (idx == VIRTIO_SCMI_CHAN_P2A && !sc->has_p2a)
+ continue;
+
+ q = &sc->vtscmi_queues[idx];
+ if (q->vq_sz == 0)
+ continue;
+
+ free(q->pdus, M_DEVBUF);
+ mtx_destroy(&q->p_mtx);
+ mtx_destroy(&q->vq_mtx);
+ }
+}
+
+static void
+vtscmi_vq_intr(void *arg)
+{
+ struct vtscmi_queue *q = arg;
+
+ /*
+ * TODO
+ * - consider pressure on RX by msg floods
+ * + Does it need a taskqueue_ like virtio/net to postpone processing
+ * under pressure ? (SCMI is low_freq compared to network though)
+ */
+ for (;;) {
+ struct vtscmi_pdu *pdu;
+ uint32_t rx_len;
+
+ mtx_lock_spin(&q->vq_mtx);
+ pdu = virtqueue_dequeue(q->vq, &rx_len);
+ mtx_unlock_spin(&q->vq_mtx);
+ if (!pdu)
+ return;
+
+ if (q->rx_callback)
+ q->rx_callback(pdu->buf, rx_len, q->priv);
+
+ /* Note that this only frees the PDU, NOT the buffer itself */
+ virtio_scmi_pdu_put(q->dev, pdu);
+ }
+}
+
+static int
+vtscmi_alloc_virtqueues(struct vtscmi_softc *sc)
+{
+ device_t dev;
+ struct vq_alloc_info vq_info[VIRTIO_SCMI_CHAN_MAX];
+
+ dev = sc->vtscmi_dev;
+ sc->vtscmi_vqs_cnt = sc->has_p2a ? 2 : 1;
+
+ VQ_ALLOC_INFO_INIT(&vq_info[VIRTIO_SCMI_CHAN_A2P], 0,
+ vtscmi_vq_intr,
+ &sc->vtscmi_queues[VIRTIO_SCMI_CHAN_A2P],
+ &sc->vtscmi_queues[VIRTIO_SCMI_CHAN_A2P].vq,
+ "%s cmdq", device_get_nameunit(dev));
+
+ if (sc->has_p2a) {
+ VQ_ALLOC_INFO_INIT(&vq_info[VIRTIO_SCMI_CHAN_P2A], 0,
+ vtscmi_vq_intr,
+ &sc->vtscmi_queues[VIRTIO_SCMI_CHAN_P2A],
+ &sc->vtscmi_queues[VIRTIO_SCMI_CHAN_P2A].vq,
+ "%s evtq", device_get_nameunit(dev));
+ }
+
+ return (virtio_alloc_virtqueues(dev, sc->vtscmi_vqs_cnt, vq_info));
+}
+
+static void *
+virtio_scmi_pdu_get(struct vtscmi_queue *q, void *buf, unsigned int tx_len,
+ unsigned int rx_len)
+{
+ struct vtscmi_pdu *pdu = NULL;
+
+ if (rx_len == 0)
+ return (NULL);
+
+ mtx_lock_spin(&q->p_mtx);
+ if (!SLIST_EMPTY(&q->p_head)) {
+ pdu = SLIST_FIRST(&q->p_head);
+ SLIST_REMOVE_HEAD(&q->p_head, next);
+ }
+ mtx_unlock_spin(&q->p_mtx);
+
+ if (pdu == NULL) {
+ device_printf(q->dev, "Cannnot allocate PDU.\n");
+ return (NULL);
+ }
+
+ /*Save msg buffer for easy access */
+ pdu->buf = buf;
+ if (tx_len != 0)
+ sglist_append(&pdu->sg, pdu->buf, tx_len);
+ sglist_append(&pdu->sg, pdu->buf, rx_len);
+
+ return (pdu);
+}
+
+static void
+virtio_scmi_pdu_put(device_t dev, struct vtscmi_pdu *pdu)
+{
+ struct vtscmi_softc *sc;
+ struct vtscmi_queue *q;
+
+ if (pdu == NULL)
+ return;
+
+ sc = device_get_softc(dev);
+ q = &sc->vtscmi_queues[pdu->chan];
+
+ sglist_reset(&pdu->sg);
+
+ mtx_lock_spin(&q->p_mtx);
+ SLIST_INSERT_HEAD(&q->p_head, pdu, next);
+ mtx_unlock_spin(&q->p_mtx);
+}
+
+device_t
+virtio_scmi_transport_get(void)
+{
+ return (vtscmi_dev);
+}
+
+int
+virtio_scmi_channel_size_get(device_t dev, enum vtscmi_chan chan)
+{
+ struct vtscmi_softc *sc;
+
+ sc = device_get_softc(dev);
+ if (chan >= sc->vtscmi_vqs_cnt)
+ return (0);
+
+ return (sc->vtscmi_queues[chan].vq_sz);
+}
+
+int
+virtio_scmi_channel_callback_set(device_t dev, enum vtscmi_chan chan,
+ virtio_scmi_rx_callback_t *cb, void *priv)
+{
+ struct vtscmi_softc *sc;
+
+ sc = device_get_softc(dev);
+ if (chan >= sc->vtscmi_vqs_cnt)
+ return (1);
+
+ if (cb == NULL)
+ virtqueue_disable_intr(sc->vtscmi_queues[chan].vq);
+
+ sc->vtscmi_queues[chan].rx_callback = cb;
+ sc->vtscmi_queues[chan].priv = priv;
+
+ /* Enable Interrupt on VQ once the callback is set */
+ if (cb != NULL)
+ /*
+ * TODO
+ * Does this need a taskqueue_ task to process already pending
+ * messages ?
+ */
+ virtqueue_enable_intr(sc->vtscmi_queues[chan].vq);
+
+ device_printf(dev, "%sabled interrupts on VQ[%d].\n",
+ cb ? "En" : "Dis", chan);
+
+ return (0);
+}
+
+int
+virtio_scmi_message_enqueue(device_t dev, enum vtscmi_chan chan,
+ void *buf, unsigned int tx_len, unsigned int rx_len)
+{
+ struct vtscmi_softc *sc;
+ struct vtscmi_pdu *pdu;
+ struct vtscmi_queue *q;
+ int ret;
+
+ sc = device_get_softc(dev);
+ if (chan >= sc->vtscmi_vqs_cnt)
+ return (1);
+
+ q = &sc->vtscmi_queues[chan];
+ pdu = virtio_scmi_pdu_get(q, buf, tx_len, rx_len);
+ if (pdu == NULL)
+ return (ENXIO);
+
+ mtx_lock_spin(&q->vq_mtx);
+ ret = virtqueue_enqueue(q->vq, pdu, &pdu->sg,
+ chan == VIRTIO_SCMI_CHAN_A2P ? 1 : 0, 1);
+ if (ret == 0)
+ virtqueue_notify(q->vq);
+ mtx_unlock_spin(&q->vq_mtx);
+
+ return (ret);
+}
+
+void *
+virtio_scmi_message_poll(device_t dev, uint32_t *rx_len)
+{
+ struct vtscmi_softc *sc;
+ struct vtscmi_queue *q;
+ struct vtscmi_pdu *pdu;
+ void *buf = NULL;
+
+ sc = device_get_softc(dev);
+
+ q = &sc->vtscmi_queues[VIRTIO_SCMI_CHAN_A2P];
+
+ mtx_lock_spin(&q->vq_mtx);
+ /* Not using virtqueue_poll since has no configurable timeout */
+ pdu = virtqueue_dequeue(q->vq, rx_len);
+ mtx_unlock_spin(&q->vq_mtx);
+ if (pdu != NULL) {
+ buf = pdu->buf;
+ virtio_scmi_pdu_put(dev, pdu);
+ }
+
+ return (buf);
+}
diff --git a/sys/dev/virtio/scmi/virtio_scmi.h b/sys/dev/virtio/scmi/virtio_scmi.h
new file mode 100644
index 000000000000..7e5c97c8b372
--- /dev/null
+++ b/sys/dev/virtio/scmi/virtio_scmi.h
@@ -0,0 +1,66 @@
+/*
+ * Virtio SCMI Device
+ *
+ * Copyright (c) 2023 Arm Ltd
+ *
+ * This header is BSD licensed so anyone can use the definitions
+ * to implement compatible drivers/servers:
+ *
+ * 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, 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.
+ * 3. Neither the name of IBM nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``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 IBM OR
+ * CONTRIBUTORS 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.
+ */
+
+#ifndef VIRTIO_SCMI_H
+#define VIRTIO_SCMI_H
+
+#include <dev/virtio/virtqueue.h>
+
+/* Features bits */
+/* Device implements some SCMI notifications, or delayed responses */
+#define VIRTIO_SCMI_F_P2A_CHANNELS (1 << 0)
+/* Device implements any SCMI statistics region */
+#define VIRTIO_SCMI_F_SHARED_MEMORY (1 << 1)
+
+#define VIRTIO_SCMI_FEATURES \
+ (VIRTIO_SCMI_F_P2A_CHANNELS | VIRTIO_SCMI_F_SHARED_MEMORY)
+
+/* Virtqueues */
+enum vtscmi_chan {
+ VIRTIO_SCMI_CHAN_A2P,
+ VIRTIO_SCMI_CHAN_P2A,
+ VIRTIO_SCMI_CHAN_MAX
+};
+
+typedef void virtio_scmi_rx_callback_t(void *msg, unsigned int len, void *priv);
+
+device_t virtio_scmi_transport_get(void);
+int virtio_scmi_channel_size_get(device_t dev, enum vtscmi_chan chan);
+int virtio_scmi_channel_callback_set(device_t dev, enum vtscmi_chan chan,
+ virtio_scmi_rx_callback_t *cb, void *priv);
+int virtio_scmi_message_enqueue(device_t dev, enum vtscmi_chan chan,
+ void *buf, unsigned int tx_len,
+ unsigned int rx_len);
+void *virtio_scmi_message_poll(device_t dev, uint32_t *rx_len);
+
+#endif
diff --git a/sys/dev/virtio/virtio.c b/sys/dev/virtio/virtio.c
index 9e375e98d1e3..75d65ba4a8c8 100644
--- a/sys/dev/virtio/virtio.c
+++ b/sys/dev/virtio/virtio.c
@@ -71,6 +71,7 @@ static struct virtio_ident {
{ VIRTIO_ID_FS, "Filesystem" },
{ VIRTIO_ID_PMEM, "Persistent Memory" },
{ VIRTIO_ID_RPMB, "RPMB" },
+ { VIRTIO_ID_SCMI, "SCMI" },
{ VIRTIO_ID_GPIO, "GPIO" },
{ 0, NULL }
diff --git a/sys/dev/virtio/virtio_ids.h b/sys/dev/virtio/virtio_ids.h
index c9bd6f52bef6..d99caa40a482 100644
--- a/sys/dev/virtio/virtio_ids.h
+++ b/sys/dev/virtio/virtio_ids.h
@@ -50,6 +50,7 @@
#define VIRTIO_ID_FS 26
#define VIRTIO_ID_PMEM 27
#define VIRTIO_ID_RPMB 28
+#define VIRTIO_ID_SCMI 32
#define VIRTIO_ID_GPIO 41
#endif /* _VIRTIO_IDS_H_ */