1 files changed, 0 insertions, 509 deletions

diff --git a/drivers/firmware/arm_scmi/virtio.c b/drivers/firmware/arm_scmi/virtio.c
deleted file mode 100644
index eefcc4146749..000000000000
--- a/drivers/firmware/arm_scmi/virtio.c
+++ /dev/null
@@ -1,509 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Virtio Transport driver for Arm System Control and Management Interface
- * (SCMI).
- *
- * Copyright (C) 2020-2021 OpenSynergy.
- * Copyright (C) 2021 ARM Ltd.
- */
-
-/**
- * DOC: Theory of Operation
- *
- * The scmi-virtio transport implements a driver for the virtio SCMI device.
- *
- * There is one Tx channel (virtio cmdq, A2P channel) and at most one Rx
- * channel (virtio eventq, P2A channel). Each channel is implemented through a
- * virtqueue. Access to each virtqueue is protected by spinlocks.
- */
-
-#include <linux/errno.h>
-#include <linux/slab.h>
-#include <linux/virtio.h>
-#include <linux/virtio_config.h>
-
-#include <uapi/linux/virtio_ids.h>
-#include <uapi/linux/virtio_scmi.h>
-
-#include "common.h"
-
-#define VIRTIO_SCMI_MAX_MSG_SIZE 128 /* Value may be increased. */
-#define VIRTIO_SCMI_MAX_PDU_SIZE \
-	(VIRTIO_SCMI_MAX_MSG_SIZE + SCMI_MSG_MAX_PROT_OVERHEAD)
-#define DESCRIPTORS_PER_TX_MSG 2
-
-/**
- * struct scmi_vio_channel - Transport channel information
- *
- * @vqueue: Associated virtqueue
- * @cinfo: SCMI Tx or Rx channel
- * @free_list: List of unused scmi_vio_msg, maintained for Tx channels only
- * @is_rx: Whether channel is an Rx channel
- * @ready: Whether transport user is ready to hear about channel
- * @max_msg: Maximum number of pending messages for this channel.
- * @lock: Protects access to all members except ready.
- * @ready_lock: Protects access to ready. If required, it must be taken before
- *              lock.
- */
-struct scmi_vio_channel {
-	struct virtqueue *vqueue;
-	struct scmi_chan_info *cinfo;
-	struct list_head free_list;
-	bool is_rx;
-	bool ready;
-	unsigned int max_msg;
-	/* lock to protect access to all members except ready. */
-	spinlock_t lock;
-	/* lock to rotects access to ready flag. */
-	spinlock_t ready_lock;
-};
-
-/**
- * struct scmi_vio_msg - Transport PDU information
- *
- * @request: SDU used for commands
- * @input: SDU used for (delayed) responses and notifications
- * @list: List which scmi_vio_msg may be part of
- * @rx_len: Input SDU size in bytes, once input has been received
- */
-struct scmi_vio_msg {
-	struct scmi_msg_payld *request;
-	struct scmi_msg_payld *input;
-	struct list_head list;
-	unsigned int rx_len;
-};
-
-/* Only one SCMI VirtIO device can possibly exist */
-static struct virtio_device *scmi_vdev;
-
-static bool scmi_vio_have_vq_rx(struct virtio_device *vdev)
-{
-	return virtio_has_feature(vdev, VIRTIO_SCMI_F_P2A_CHANNELS);
-}
-
-static int scmi_vio_feed_vq_rx(struct scmi_vio_channel *vioch,
-			       struct scmi_vio_msg *msg,
-			       struct device *dev)
-{
-	struct scatterlist sg_in;
-	int rc;
-	unsigned long flags;
-
-	sg_init_one(&sg_in, msg->input, VIRTIO_SCMI_MAX_PDU_SIZE);
-
-	spin_lock_irqsave(&vioch->lock, flags);
-
-	rc = virtqueue_add_inbuf(vioch->vqueue, &sg_in, 1, msg, GFP_ATOMIC);
-	if (rc)
-		dev_err_once(dev, "failed to add to virtqueue (%d)\n", rc);
-	else
-		virtqueue_kick(vioch->vqueue);
-
-	spin_unlock_irqrestore(&vioch->lock, flags);
-
-	return rc;
-}
-
-static void scmi_finalize_message(struct scmi_vio_channel *vioch,
-				  struct scmi_vio_msg *msg)
-{
-	if (vioch->is_rx) {
-		scmi_vio_feed_vq_rx(vioch, msg, vioch->cinfo->dev);
-	} else {
-		/* Here IRQs are assumed to be already disabled by the caller */
-		spin_lock(&vioch->lock);
-		list_add(&msg->list, &vioch->free_list);
-		spin_unlock(&vioch->lock);
-	}
-}
-
-static void scmi_vio_complete_cb(struct virtqueue *vqueue)
-{
-	unsigned long ready_flags;
-	unsigned int length;
-	struct scmi_vio_channel *vioch;
-	struct scmi_vio_msg *msg;
-	bool cb_enabled = true;
-
-	if (WARN_ON_ONCE(!vqueue->vdev->priv))
-		return;
-	vioch = &((struct scmi_vio_channel *)vqueue->vdev->priv)[vqueue->index];
-
-	for (;;) {
-		spin_lock_irqsave(&vioch->ready_lock, ready_flags);
-
-		if (!vioch->ready) {
-			if (!cb_enabled)
-				(void)virtqueue_enable_cb(vqueue);
-			goto unlock_ready_out;
-		}
-
-		/* IRQs already disabled here no need to irqsave */
-		spin_lock(&vioch->lock);
-		if (cb_enabled) {
-			virtqueue_disable_cb(vqueue);
-			cb_enabled = false;
-		}
-		msg = virtqueue_get_buf(vqueue, &length);
-		if (!msg) {
-			if (virtqueue_enable_cb(vqueue))
-				goto unlock_out;
-			cb_enabled = true;
-		}
-		spin_unlock(&vioch->lock);
-
-		if (msg) {
-			msg->rx_len = length;
-			scmi_rx_callback(vioch->cinfo,
-					 msg_read_header(msg->input), msg);
-
-			scmi_finalize_message(vioch, msg);
-		}
-
-		/*
-		 * Release ready_lock and re-enable IRQs between loop iterations
-		 * to allow virtio_chan_free() to possibly kick in and set the
-		 * flag vioch->ready to false even in between processing of
-		 * messages, so as to force outstanding messages to be ignored
-		 * when system is shutting down.
-		 */
-		spin_unlock_irqrestore(&vioch->ready_lock, ready_flags);
-	}
-
-unlock_out:
-	spin_unlock(&vioch->lock);
-unlock_ready_out:
-	spin_unlock_irqrestore(&vioch->ready_lock, ready_flags);
-}
-
-static const char *const scmi_vio_vqueue_names[] = { "tx", "rx" };
-
-static vq_callback_t *scmi_vio_complete_callbacks[] = {
-	scmi_vio_complete_cb,
-	scmi_vio_complete_cb
-};
-
-static unsigned int virtio_get_max_msg(struct scmi_chan_info *base_cinfo)
-{
-	struct scmi_vio_channel *vioch = base_cinfo->transport_info;
-
-	return vioch->max_msg;
-}
-
-static int virtio_link_supplier(struct device *dev)
-{
-	if (!scmi_vdev) {
-		dev_notice_once(dev,
-				"Deferring probe after not finding a bound scmi-virtio device\n");
-		return -EPROBE_DEFER;
-	}
-
-	if (!device_link_add(dev, &scmi_vdev->dev,
-			     DL_FLAG_AUTOREMOVE_CONSUMER)) {
-		dev_err(dev, "Adding link to supplier virtio device failed\n");
-		return -ECANCELED;
-	}
-
-	return 0;
-}
-
-static bool virtio_chan_available(struct device *dev, int idx)
-{
-	struct scmi_vio_channel *channels, *vioch = NULL;
-
-	if (WARN_ON_ONCE(!scmi_vdev))
-		return false;
-
-	channels = (struct scmi_vio_channel *)scmi_vdev->priv;
-
-	switch (idx) {
-	case VIRTIO_SCMI_VQ_TX:
-		vioch = &channels[VIRTIO_SCMI_VQ_TX];
-		break;
-	case VIRTIO_SCMI_VQ_RX:
-		if (scmi_vio_have_vq_rx(scmi_vdev))
-			vioch = &channels[VIRTIO_SCMI_VQ_RX];
-		break;
-	default:
-		return false;
-	}
-
-	return vioch && !vioch->cinfo;
-}
-
-static int virtio_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
-			     bool tx)
-{
-	unsigned long flags;
-	struct scmi_vio_channel *vioch;
-	int index = tx ? VIRTIO_SCMI_VQ_TX : VIRTIO_SCMI_VQ_RX;
-	int i;
-
-	if (!scmi_vdev)
-		return -EPROBE_DEFER;
-
-	vioch = &((struct scmi_vio_channel *)scmi_vdev->priv)[index];
-
-	for (i = 0; i < vioch->max_msg; i++) {
-		struct scmi_vio_msg *msg;
-
-		msg = devm_kzalloc(cinfo->dev, sizeof(*msg), GFP_KERNEL);
-		if (!msg)
-			return -ENOMEM;
-
-		if (tx) {
-			msg->request = devm_kzalloc(cinfo->dev,
-						    VIRTIO_SCMI_MAX_PDU_SIZE,
-						    GFP_KERNEL);
-			if (!msg->request)
-				return -ENOMEM;
-		}
-
-		msg->input = devm_kzalloc(cinfo->dev, VIRTIO_SCMI_MAX_PDU_SIZE,
-					  GFP_KERNEL);
-		if (!msg->input)
-			return -ENOMEM;
-
-		if (tx) {
-			spin_lock_irqsave(&vioch->lock, flags);
-			list_add_tail(&msg->list, &vioch->free_list);
-			spin_unlock_irqrestore(&vioch->lock, flags);
-		} else {
-			scmi_vio_feed_vq_rx(vioch, msg, cinfo->dev);
-		}
-	}
-
-	spin_lock_irqsave(&vioch->lock, flags);
-	cinfo->transport_info = vioch;
-	/* Indirectly setting channel not available any more */
-	vioch->cinfo = cinfo;
-	spin_unlock_irqrestore(&vioch->lock, flags);
-
-	spin_lock_irqsave(&vioch->ready_lock, flags);
-	vioch->ready = true;
-	spin_unlock_irqrestore(&vioch->ready_lock, flags);
-
-	return 0;
-}
-
-static int virtio_chan_free(int id, void *p, void *data)
-{
-	unsigned long flags;
-	struct scmi_chan_info *cinfo = p;
-	struct scmi_vio_channel *vioch = cinfo->transport_info;
-
-	spin_lock_irqsave(&vioch->ready_lock, flags);
-	vioch->ready = false;
-	spin_unlock_irqrestore(&vioch->ready_lock, flags);
-
-	scmi_free_channel(cinfo, data, id);
-
-	spin_lock_irqsave(&vioch->lock, flags);
-	vioch->cinfo = NULL;
-	spin_unlock_irqrestore(&vioch->lock, flags);
-
-	return 0;
-}
-
-static int virtio_send_message(struct scmi_chan_info *cinfo,
-			       struct scmi_xfer *xfer)
-{
-	struct scmi_vio_channel *vioch = cinfo->transport_info;
-	struct scatterlist sg_out;
-	struct scatterlist sg_in;
-	struct scatterlist *sgs[DESCRIPTORS_PER_TX_MSG] = { &sg_out, &sg_in };
-	unsigned long flags;
-	int rc;
-	struct scmi_vio_msg *msg;
-
-	spin_lock_irqsave(&vioch->lock, flags);
-
-	if (list_empty(&vioch->free_list)) {
-		spin_unlock_irqrestore(&vioch->lock, flags);
-		return -EBUSY;
-	}
-
-	msg = list_first_entry(&vioch->free_list, typeof(*msg), list);
-	list_del(&msg->list);
-
-	msg_tx_prepare(msg->request, xfer);
-
-	sg_init_one(&sg_out, msg->request, msg_command_size(xfer));
-	sg_init_one(&sg_in, msg->input, msg_response_size(xfer));
-
-	rc = virtqueue_add_sgs(vioch->vqueue, sgs, 1, 1, msg, GFP_ATOMIC);
-	if (rc) {
-		list_add(&msg->list, &vioch->free_list);
-		dev_err_once(vioch->cinfo->dev,
-			     "%s() failed to add to virtqueue (%d)\n", __func__,
-			     rc);
-	} else {
-		virtqueue_kick(vioch->vqueue);
-	}
-
-	spin_unlock_irqrestore(&vioch->lock, flags);
-
-	return rc;
-}
-
-static void virtio_fetch_response(struct scmi_chan_info *cinfo,
-				  struct scmi_xfer *xfer)
-{
-	struct scmi_vio_msg *msg = xfer->priv;
-
-	if (msg) {
-		msg_fetch_response(msg->input, msg->rx_len, xfer);
-		xfer->priv = NULL;
-	}
-}
-
-static void virtio_fetch_notification(struct scmi_chan_info *cinfo,
-				      size_t max_len, struct scmi_xfer *xfer)
-{
-	struct scmi_vio_msg *msg = xfer->priv;
-
-	if (msg) {
-		msg_fetch_notification(msg->input, msg->rx_len, max_len, xfer);
-		xfer->priv = NULL;
-	}
-}
-
-static const struct scmi_transport_ops scmi_virtio_ops = {
-	.link_supplier = virtio_link_supplier,
-	.chan_available = virtio_chan_available,
-	.chan_setup = virtio_chan_setup,
-	.chan_free = virtio_chan_free,
-	.get_max_msg = virtio_get_max_msg,
-	.send_message = virtio_send_message,
-	.fetch_response = virtio_fetch_response,
-	.fetch_notification = virtio_fetch_notification,
-};
-
-static int scmi_vio_probe(struct virtio_device *vdev)
-{
-	struct device *dev = &vdev->dev;
-	struct scmi_vio_channel *channels;
-	bool have_vq_rx;
-	int vq_cnt;
-	int i;
-	int ret;
-	struct virtqueue *vqs[VIRTIO_SCMI_VQ_MAX_CNT];
-
-	/* Only one SCMI VirtiO device allowed */
-	if (scmi_vdev) {
-		dev_err(dev,
-			"One SCMI Virtio device was already initialized: only one allowed.\n");
-		return -EBUSY;
-	}
-
-	have_vq_rx = scmi_vio_have_vq_rx(vdev);
-	vq_cnt = have_vq_rx ? VIRTIO_SCMI_VQ_MAX_CNT : 1;
-
-	channels = devm_kcalloc(dev, vq_cnt, sizeof(*channels), GFP_KERNEL);
-	if (!channels)
-		return -ENOMEM;
-
-	if (have_vq_rx)
-		channels[VIRTIO_SCMI_VQ_RX].is_rx = true;
-
-	ret = virtio_find_vqs(vdev, vq_cnt, vqs, scmi_vio_complete_callbacks,
-			      scmi_vio_vqueue_names, NULL);
-	if (ret) {
-		dev_err(dev, "Failed to get %d virtqueue(s)\n", vq_cnt);
-		return ret;
-	}
-
-	for (i = 0; i < vq_cnt; i++) {
-		unsigned int sz;
-
-		spin_lock_init(&channels[i].lock);
-		spin_lock_init(&channels[i].ready_lock);
-		INIT_LIST_HEAD(&channels[i].free_list);
-		channels[i].vqueue = vqs[i];
-
-		sz = virtqueue_get_vring_size(channels[i].vqueue);
-		/* Tx messages need multiple descriptors. */
-		if (!channels[i].is_rx)
-			sz /= DESCRIPTORS_PER_TX_MSG;
-
-		if (sz > MSG_TOKEN_MAX) {
-			dev_info_once(dev,
-				      "%s virtqueue could hold %d messages. Only %ld allowed to be pending.\n",
-				      channels[i].is_rx ? "rx" : "tx",
-				      sz, MSG_TOKEN_MAX);
-			sz = MSG_TOKEN_MAX;
-		}
-		channels[i].max_msg = sz;
-	}
-
-	vdev->priv = channels;
-	/* Ensure initialized scmi_vdev is visible */
-	smp_store_mb(scmi_vdev, vdev);
-
-	return 0;
-}
-
-static void scmi_vio_remove(struct virtio_device *vdev)
-{
-	/*
-	 * Once we get here, virtio_chan_free() will have already been called by
-	 * the SCMI core for any existing channel and, as a consequence, all the
-	 * virtio channels will have been already marked NOT ready, causing any
-	 * outstanding message on any vqueue to be ignored by complete_cb: now
-	 * we can just stop processing buffers and destroy the vqueues.
-	 */
-	virtio_reset_device(vdev);
-	vdev->config->del_vqs(vdev);
-	/* Ensure scmi_vdev is visible as NULL */
-	smp_store_mb(scmi_vdev, NULL);
-}
-
-static int scmi_vio_validate(struct virtio_device *vdev)
-{
-	if (!virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) {
-		dev_err(&vdev->dev,
-			"device does not comply with spec version 1.x\n");
-		return -EINVAL;
-	}
-
-	return 0;
-}
-
-static unsigned int features[] = {
-	VIRTIO_SCMI_F_P2A_CHANNELS,
-};
-
-static const struct virtio_device_id id_table[] = {
-	{ VIRTIO_ID_SCMI, VIRTIO_DEV_ANY_ID },
-	{ 0 }
-};
-
-static struct virtio_driver virtio_scmi_driver = {
-	.driver.name = "scmi-virtio",
-	.driver.owner = THIS_MODULE,
-	.feature_table = features,
-	.feature_table_size = ARRAY_SIZE(features),
-	.id_table = id_table,
-	.probe = scmi_vio_probe,
-	.remove = scmi_vio_remove,
-	.validate = scmi_vio_validate,
-};
-
-static int __init virtio_scmi_init(void)
-{
-	return register_virtio_driver(&virtio_scmi_driver);
-}
-
-static void virtio_scmi_exit(void)
-{
-	unregister_virtio_driver(&virtio_scmi_driver);
-}
-
-const struct scmi_desc scmi_virtio_desc = {
-	.transport_init = virtio_scmi_init,
-	.transport_exit = virtio_scmi_exit,
-	.ops = &scmi_virtio_ops,
-	.max_rx_timeout_ms = 60000, /* for non-realtime virtio devices */
-	.max_msg = 0, /* overridden by virtio_get_max_msg() */
-	.max_msg_size = VIRTIO_SCMI_MAX_MSG_SIZE,
-};