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

@@ -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

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
 

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

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);
+}

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

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 }

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_ */