1 files changed, 659 insertions, 0 deletions

diff --git a/drivers/net/wwan/mhi_wwan_mbim.c b/drivers/net/wwan/mhi_wwan_mbim.c
new file mode 100644
index 000000000..ef70bb7c8
--- /dev/null
+++ b/drivers/net/wwan/mhi_wwan_mbim.c
@@ -0,0 +1,659 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* MHI MBIM Network driver - Network/MBIM over MHI bus
+ *
+ * Copyright (C) 2021 Linaro Ltd <loic.poulain@linaro.org>
+ *
+ * This driver copy some code from cdc_ncm, which is:
+ * Copyright (C) ST-Ericsson 2010-2012
+ * and cdc_mbim, which is:
+ * Copyright (c) 2012  Smith Micro Software, Inc.
+ * Copyright (c) 2012  Bjørn Mork <bjorn@mork.no>
+ *
+ */
+
+#include <linux/ethtool.h>
+#include <linux/if_arp.h>
+#include <linux/if_vlan.h>
+#include <linux/ip.h>
+#include <linux/mhi.h>
+#include <linux/mii.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <linux/u64_stats_sync.h>
+#include <linux/usb.h>
+#include <linux/usb/cdc.h>
+#include <linux/usb/usbnet.h>
+#include <linux/usb/cdc_ncm.h>
+#include <linux/wwan.h>
+
+/* 3500 allows to optimize skb allocation, the skbs will basically fit in
+ * one 4K page. Large MBIM packets will simply be split over several MHI
+ * transfers and chained by the MHI net layer (zerocopy).
+ */
+#define MHI_DEFAULT_MRU 3500
+
+#define MHI_MBIM_DEFAULT_MTU 1500
+#define MHI_MAX_BUF_SZ 0xffff
+
+#define MBIM_NDP16_SIGN_MASK 0x00ffffff
+
+#define MHI_MBIM_LINK_HASH_SIZE 8
+#define LINK_HASH(session) ((session) % MHI_MBIM_LINK_HASH_SIZE)
+
+struct mhi_mbim_link {
+	struct mhi_mbim_context *mbim;
+	struct net_device *ndev;
+	unsigned int session;
+
+	/* stats */
+	u64_stats_t rx_packets;
+	u64_stats_t rx_bytes;
+	u64_stats_t rx_errors;
+	u64_stats_t tx_packets;
+	u64_stats_t tx_bytes;
+	u64_stats_t tx_errors;
+	u64_stats_t tx_dropped;
+	struct u64_stats_sync tx_syncp;
+	struct u64_stats_sync rx_syncp;
+
+	struct hlist_node hlnode;
+};
+
+struct mhi_mbim_context {
+	struct mhi_device *mdev;
+	struct sk_buff *skbagg_head;
+	struct sk_buff *skbagg_tail;
+	unsigned int mru;
+	u32 rx_queue_sz;
+	u16 rx_seq;
+	u16 tx_seq;
+	struct delayed_work rx_refill;
+	spinlock_t tx_lock;
+	struct hlist_head link_list[MHI_MBIM_LINK_HASH_SIZE];
+};
+
+struct mbim_tx_hdr {
+	struct usb_cdc_ncm_nth16 nth16;
+	struct usb_cdc_ncm_ndp16 ndp16;
+	struct usb_cdc_ncm_dpe16 dpe16[2];
+} __packed;
+
+static struct mhi_mbim_link *mhi_mbim_get_link_rcu(struct mhi_mbim_context *mbim,
+						   unsigned int session)
+{
+	struct mhi_mbim_link *link;
+
+	hlist_for_each_entry_rcu(link, &mbim->link_list[LINK_HASH(session)], hlnode) {
+		if (link->session == session)
+			return link;
+	}
+
+	return NULL;
+}
+
+static struct sk_buff *mbim_tx_fixup(struct sk_buff *skb, unsigned int session,
+				     u16 tx_seq)
+{
+	unsigned int dgram_size = skb->len;
+	struct usb_cdc_ncm_nth16 *nth16;
+	struct usb_cdc_ncm_ndp16 *ndp16;
+	struct mbim_tx_hdr *mbim_hdr;
+
+	/* Only one NDP is sent, containing the IP packet (no aggregation) */
+
+	/* Ensure we have enough headroom for crafting MBIM header */
+	if (skb_cow_head(skb, sizeof(struct mbim_tx_hdr))) {
+		dev_kfree_skb_any(skb);
+		return NULL;
+	}
+
+	mbim_hdr = skb_push(skb, sizeof(struct mbim_tx_hdr));
+
+	/* Fill NTB header */
+	nth16 = &mbim_hdr->nth16;
+	nth16->dwSignature = cpu_to_le32(USB_CDC_NCM_NTH16_SIGN);
+	nth16->wHeaderLength = cpu_to_le16(sizeof(struct usb_cdc_ncm_nth16));
+	nth16->wSequence = cpu_to_le16(tx_seq);
+	nth16->wBlockLength = cpu_to_le16(skb->len);
+	nth16->wNdpIndex = cpu_to_le16(sizeof(struct usb_cdc_ncm_nth16));
+
+	/* Fill the unique NDP */
+	ndp16 = &mbim_hdr->ndp16;
+	ndp16->dwSignature = cpu_to_le32(USB_CDC_MBIM_NDP16_IPS_SIGN | (session << 24));
+	ndp16->wLength = cpu_to_le16(sizeof(struct usb_cdc_ncm_ndp16)
+					+ sizeof(struct usb_cdc_ncm_dpe16) * 2);
+	ndp16->wNextNdpIndex = 0;
+
+	/* Datagram follows the mbim header */
+	ndp16->dpe16[0].wDatagramIndex = cpu_to_le16(sizeof(struct mbim_tx_hdr));
+	ndp16->dpe16[0].wDatagramLength = cpu_to_le16(dgram_size);
+
+	/* null termination */
+	ndp16->dpe16[1].wDatagramIndex = 0;
+	ndp16->dpe16[1].wDatagramLength = 0;
+
+	return skb;
+}
+
+static netdev_tx_t mhi_mbim_ndo_xmit(struct sk_buff *skb, struct net_device *ndev)
+{
+	struct mhi_mbim_link *link = wwan_netdev_drvpriv(ndev);
+	struct mhi_mbim_context *mbim = link->mbim;
+	unsigned long flags;
+	int err = -ENOMEM;
+
+	/* Serialize MHI channel queuing and MBIM seq */
+	spin_lock_irqsave(&mbim->tx_lock, flags);
+
+	skb = mbim_tx_fixup(skb, link->session, mbim->tx_seq);
+	if (unlikely(!skb))
+		goto exit_unlock;
+
+	err = mhi_queue_skb(mbim->mdev, DMA_TO_DEVICE, skb, skb->len, MHI_EOT);
+
+	if (mhi_queue_is_full(mbim->mdev, DMA_TO_DEVICE))
+		netif_stop_queue(ndev);
+
+	if (!err)
+		mbim->tx_seq++;
+
+exit_unlock:
+	spin_unlock_irqrestore(&mbim->tx_lock, flags);
+
+	if (unlikely(err)) {
+		net_err_ratelimited("%s: Failed to queue TX buf (%d)\n",
+				    ndev->name, err);
+		dev_kfree_skb_any(skb);
+		goto exit_drop;
+	}
+
+	return NETDEV_TX_OK;
+
+exit_drop:
+	u64_stats_update_begin(&link->tx_syncp);
+	u64_stats_inc(&link->tx_dropped);
+	u64_stats_update_end(&link->tx_syncp);
+
+	return NETDEV_TX_OK;
+}
+
+static int mbim_rx_verify_nth16(struct mhi_mbim_context *mbim, struct sk_buff *skb)
+{
+	struct usb_cdc_ncm_nth16 *nth16;
+	int len;
+
+	if (skb->len < sizeof(struct usb_cdc_ncm_nth16) +
+			sizeof(struct usb_cdc_ncm_ndp16)) {
+		net_err_ratelimited("frame too short\n");
+		return -EINVAL;
+	}
+
+	nth16 = (struct usb_cdc_ncm_nth16 *)skb->data;
+
+	if (nth16->dwSignature != cpu_to_le32(USB_CDC_NCM_NTH16_SIGN)) {
+		net_err_ratelimited("invalid NTH16 signature <%#010x>\n",
+				    le32_to_cpu(nth16->dwSignature));
+		return -EINVAL;
+	}
+
+	/* No limit on the block length, except the size of the data pkt */
+	len = le16_to_cpu(nth16->wBlockLength);
+	if (len > skb->len) {
+		net_err_ratelimited("NTB does not fit into the skb %u/%u\n",
+				    len, skb->len);
+		return -EINVAL;
+	}
+
+	if (mbim->rx_seq + 1 != le16_to_cpu(nth16->wSequence) &&
+	    (mbim->rx_seq || le16_to_cpu(nth16->wSequence)) &&
+	    !(mbim->rx_seq == 0xffff && !le16_to_cpu(nth16->wSequence))) {
+		net_err_ratelimited("sequence number glitch prev=%d curr=%d\n",
+				    mbim->rx_seq, le16_to_cpu(nth16->wSequence));
+	}
+	mbim->rx_seq = le16_to_cpu(nth16->wSequence);
+
+	return le16_to_cpu(nth16->wNdpIndex);
+}
+
+static int mbim_rx_verify_ndp16(struct sk_buff *skb, struct usb_cdc_ncm_ndp16 *ndp16)
+{
+	int ret;
+
+	if (le16_to_cpu(ndp16->wLength) < USB_CDC_NCM_NDP16_LENGTH_MIN) {
+		net_err_ratelimited("invalid DPT16 length <%u>\n",
+				    le16_to_cpu(ndp16->wLength));
+		return -EINVAL;
+	}
+
+	ret = ((le16_to_cpu(ndp16->wLength) - sizeof(struct usb_cdc_ncm_ndp16))
+			/ sizeof(struct usb_cdc_ncm_dpe16));
+	ret--; /* Last entry is always a NULL terminator */
+
+	if (sizeof(struct usb_cdc_ncm_ndp16) +
+	     ret * sizeof(struct usb_cdc_ncm_dpe16) > skb->len) {
+		net_err_ratelimited("Invalid nframes = %d\n", ret);
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+static void mhi_mbim_rx(struct mhi_mbim_context *mbim, struct sk_buff *skb)
+{
+	int ndpoffset;
+
+	/* Check NTB header and retrieve first NDP offset */
+	ndpoffset = mbim_rx_verify_nth16(mbim, skb);
+	if (ndpoffset < 0) {
+		net_err_ratelimited("mbim: Incorrect NTB header\n");
+		goto error;
+	}
+
+	/* Process each NDP */
+	while (1) {
+		struct usb_cdc_ncm_ndp16 ndp16;
+		struct usb_cdc_ncm_dpe16 dpe16;
+		struct mhi_mbim_link *link;
+		int nframes, n, dpeoffset;
+		unsigned int session;
+
+		if (skb_copy_bits(skb, ndpoffset, &ndp16, sizeof(ndp16))) {
+			net_err_ratelimited("mbim: Incorrect NDP offset (%u)\n",
+					    ndpoffset);
+			goto error;
+		}
+
+		/* Check NDP header and retrieve number of datagrams */
+		nframes = mbim_rx_verify_ndp16(skb, &ndp16);
+		if (nframes < 0) {
+			net_err_ratelimited("mbim: Incorrect NDP16\n");
+			goto error;
+		}
+
+		 /* Only IP data type supported, no DSS in MHI context */
+		if ((ndp16.dwSignature & cpu_to_le32(MBIM_NDP16_SIGN_MASK))
+				!= cpu_to_le32(USB_CDC_MBIM_NDP16_IPS_SIGN)) {
+			net_err_ratelimited("mbim: Unsupported NDP type\n");
+			goto next_ndp;
+		}
+
+		session = (le32_to_cpu(ndp16.dwSignature) & ~MBIM_NDP16_SIGN_MASK) >> 24;
+
+		rcu_read_lock();
+
+		link = mhi_mbim_get_link_rcu(mbim, session);
+		if (!link) {
+			net_err_ratelimited("mbim: bad packet session (%u)\n", session);
+			goto unlock;
+		}
+
+		/* de-aggregate and deliver IP packets */
+		dpeoffset = ndpoffset + sizeof(struct usb_cdc_ncm_ndp16);
+		for (n = 0; n < nframes; n++, dpeoffset += sizeof(dpe16)) {
+			u16 dgram_offset, dgram_len;
+			struct sk_buff *skbn;
+
+			if (skb_copy_bits(skb, dpeoffset, &dpe16, sizeof(dpe16)))
+				break;
+
+			dgram_offset = le16_to_cpu(dpe16.wDatagramIndex);
+			dgram_len = le16_to_cpu(dpe16.wDatagramLength);
+
+			if (!dgram_offset || !dgram_len)
+				break; /* null terminator */
+
+			skbn = netdev_alloc_skb(link->ndev, dgram_len);
+			if (!skbn)
+				continue;
+
+			skb_put(skbn, dgram_len);
+			skb_copy_bits(skb, dgram_offset, skbn->data, dgram_len);
+
+			switch (skbn->data[0] & 0xf0) {
+			case 0x40:
+				skbn->protocol = htons(ETH_P_IP);
+				break;
+			case 0x60:
+				skbn->protocol = htons(ETH_P_IPV6);
+				break;
+			default:
+				net_err_ratelimited("%s: unknown protocol\n",
+						    link->ndev->name);
+				dev_kfree_skb_any(skbn);
+				u64_stats_update_begin(&link->rx_syncp);
+				u64_stats_inc(&link->rx_errors);
+				u64_stats_update_end(&link->rx_syncp);
+				continue;
+			}
+
+			u64_stats_update_begin(&link->rx_syncp);
+			u64_stats_inc(&link->rx_packets);
+			u64_stats_add(&link->rx_bytes, skbn->len);
+			u64_stats_update_end(&link->rx_syncp);
+
+			netif_rx(skbn);
+		}
+unlock:
+		rcu_read_unlock();
+next_ndp:
+		/* Other NDP to process? */
+		ndpoffset = (int)le16_to_cpu(ndp16.wNextNdpIndex);
+		if (!ndpoffset)
+			break;
+	}
+
+	/* free skb */
+	dev_consume_skb_any(skb);
+	return;
+error:
+	dev_kfree_skb_any(skb);
+}
+
+static struct sk_buff *mhi_net_skb_agg(struct mhi_mbim_context *mbim,
+				       struct sk_buff *skb)
+{
+	struct sk_buff *head = mbim->skbagg_head;
+	struct sk_buff *tail = mbim->skbagg_tail;
+
+	/* This is non-paged skb chaining using frag_list */
+	if (!head) {
+		mbim->skbagg_head = skb;
+		return skb;
+	}
+
+	if (!skb_shinfo(head)->frag_list)
+		skb_shinfo(head)->frag_list = skb;
+	else
+		tail->next = skb;
+
+	head->len += skb->len;
+	head->data_len += skb->len;
+	head->truesize += skb->truesize;
+
+	mbim->skbagg_tail = skb;
+
+	return mbim->skbagg_head;
+}
+
+static void mhi_net_rx_refill_work(struct work_struct *work)
+{
+	struct mhi_mbim_context *mbim = container_of(work, struct mhi_mbim_context,
+						     rx_refill.work);
+	struct mhi_device *mdev = mbim->mdev;
+	int err;
+
+	while (!mhi_queue_is_full(mdev, DMA_FROM_DEVICE)) {
+		struct sk_buff *skb = alloc_skb(mbim->mru, GFP_KERNEL);
+
+		if (unlikely(!skb))
+			break;
+
+		err = mhi_queue_skb(mdev, DMA_FROM_DEVICE, skb,
+				    mbim->mru, MHI_EOT);
+		if (unlikely(err)) {
+			kfree_skb(skb);
+			break;
+		}
+
+		/* Do not hog the CPU if rx buffers are consumed faster than
+		 * queued (unlikely).
+		 */
+		cond_resched();
+	}
+
+	/* If we're still starved of rx buffers, reschedule later */
+	if (mhi_get_free_desc_count(mdev, DMA_FROM_DEVICE) == mbim->rx_queue_sz)
+		schedule_delayed_work(&mbim->rx_refill, HZ / 2);
+}
+
+static void mhi_mbim_dl_callback(struct mhi_device *mhi_dev,
+				 struct mhi_result *mhi_res)
+{
+	struct mhi_mbim_context *mbim = dev_get_drvdata(&mhi_dev->dev);
+	struct sk_buff *skb = mhi_res->buf_addr;
+	int free_desc_count;
+
+	free_desc_count = mhi_get_free_desc_count(mhi_dev, DMA_FROM_DEVICE);
+
+	if (unlikely(mhi_res->transaction_status)) {
+		switch (mhi_res->transaction_status) {
+		case -EOVERFLOW:
+			/* Packet has been split over multiple transfers */
+			skb_put(skb, mhi_res->bytes_xferd);
+			mhi_net_skb_agg(mbim, skb);
+			break;
+		case -ENOTCONN:
+			/* MHI layer stopping/resetting the DL channel */
+			dev_kfree_skb_any(skb);
+			return;
+		default:
+			/* Unknown error, simply drop */
+			dev_kfree_skb_any(skb);
+		}
+	} else {
+		skb_put(skb, mhi_res->bytes_xferd);
+
+		if (mbim->skbagg_head) {
+			/* Aggregate the final fragment */
+			skb = mhi_net_skb_agg(mbim, skb);
+			mbim->skbagg_head = NULL;
+		}
+
+		mhi_mbim_rx(mbim, skb);
+	}
+
+	/* Refill if RX buffers queue becomes low */
+	if (free_desc_count >= mbim->rx_queue_sz / 2)
+		schedule_delayed_work(&mbim->rx_refill, 0);
+}
+
+static void mhi_mbim_ndo_get_stats64(struct net_device *ndev,
+				     struct rtnl_link_stats64 *stats)
+{
+	struct mhi_mbim_link *link = wwan_netdev_drvpriv(ndev);
+	unsigned int start;
+
+	do {
+		start = u64_stats_fetch_begin_irq(&link->rx_syncp);
+		stats->rx_packets = u64_stats_read(&link->rx_packets);
+		stats->rx_bytes = u64_stats_read(&link->rx_bytes);
+		stats->rx_errors = u64_stats_read(&link->rx_errors);
+	} while (u64_stats_fetch_retry_irq(&link->rx_syncp, start));
+
+	do {
+		start = u64_stats_fetch_begin_irq(&link->tx_syncp);
+		stats->tx_packets = u64_stats_read(&link->tx_packets);
+		stats->tx_bytes = u64_stats_read(&link->tx_bytes);
+		stats->tx_errors = u64_stats_read(&link->tx_errors);
+		stats->tx_dropped = u64_stats_read(&link->tx_dropped);
+	} while (u64_stats_fetch_retry_irq(&link->tx_syncp, start));
+}
+
+static void mhi_mbim_ul_callback(struct mhi_device *mhi_dev,
+				 struct mhi_result *mhi_res)
+{
+	struct mhi_mbim_context *mbim = dev_get_drvdata(&mhi_dev->dev);
+	struct sk_buff *skb = mhi_res->buf_addr;
+	struct net_device *ndev = skb->dev;
+	struct mhi_mbim_link *link = wwan_netdev_drvpriv(ndev);
+
+	/* Hardware has consumed the buffer, so free the skb (which is not
+	 * freed by the MHI stack) and perform accounting.
+	 */
+	dev_consume_skb_any(skb);
+
+	u64_stats_update_begin(&link->tx_syncp);
+	if (unlikely(mhi_res->transaction_status)) {
+		/* MHI layer stopping/resetting the UL channel */
+		if (mhi_res->transaction_status == -ENOTCONN) {
+			u64_stats_update_end(&link->tx_syncp);
+			return;
+		}
+
+		u64_stats_inc(&link->tx_errors);
+	} else {
+		u64_stats_inc(&link->tx_packets);
+		u64_stats_add(&link->tx_bytes, mhi_res->bytes_xferd);
+	}
+	u64_stats_update_end(&link->tx_syncp);
+
+	if (netif_queue_stopped(ndev) && !mhi_queue_is_full(mbim->mdev, DMA_TO_DEVICE))
+		netif_wake_queue(ndev);
+}
+
+static int mhi_mbim_ndo_open(struct net_device *ndev)
+{
+	struct mhi_mbim_link *link = wwan_netdev_drvpriv(ndev);
+
+	/* Feed the MHI rx buffer pool */
+	schedule_delayed_work(&link->mbim->rx_refill, 0);
+
+	/* Carrier is established via out-of-band channel (e.g. qmi) */
+	netif_carrier_on(ndev);
+
+	netif_start_queue(ndev);
+
+	return 0;
+}
+
+static int mhi_mbim_ndo_stop(struct net_device *ndev)
+{
+	netif_stop_queue(ndev);
+	netif_carrier_off(ndev);
+
+	return 0;
+}
+
+static const struct net_device_ops mhi_mbim_ndo = {
+	.ndo_open = mhi_mbim_ndo_open,
+	.ndo_stop = mhi_mbim_ndo_stop,
+	.ndo_start_xmit = mhi_mbim_ndo_xmit,
+	.ndo_get_stats64 = mhi_mbim_ndo_get_stats64,
+};
+
+static int mhi_mbim_newlink(void *ctxt, struct net_device *ndev, u32 if_id,
+			    struct netlink_ext_ack *extack)
+{
+	struct mhi_mbim_link *link = wwan_netdev_drvpriv(ndev);
+	struct mhi_mbim_context *mbim = ctxt;
+
+	link->session = if_id;
+	link->mbim = mbim;
+	link->ndev = ndev;
+	u64_stats_init(&link->rx_syncp);
+	u64_stats_init(&link->tx_syncp);
+
+	rcu_read_lock();
+	if (mhi_mbim_get_link_rcu(mbim, if_id)) {
+		rcu_read_unlock();
+		return -EEXIST;
+	}
+	rcu_read_unlock();
+
+	/* Already protected by RTNL lock */
+	hlist_add_head_rcu(&link->hlnode, &mbim->link_list[LINK_HASH(if_id)]);
+
+	return register_netdevice(ndev);
+}
+
+static void mhi_mbim_dellink(void *ctxt, struct net_device *ndev,
+			     struct list_head *head)
+{
+	struct mhi_mbim_link *link = wwan_netdev_drvpriv(ndev);
+
+	hlist_del_init_rcu(&link->hlnode);
+	synchronize_rcu();
+
+	unregister_netdevice_queue(ndev, head);
+}
+
+static void mhi_mbim_setup(struct net_device *ndev)
+{
+	ndev->header_ops = NULL;  /* No header */
+	ndev->type = ARPHRD_RAWIP;
+	ndev->needed_headroom = sizeof(struct mbim_tx_hdr);
+	ndev->hard_header_len = 0;
+	ndev->addr_len = 0;
+	ndev->flags = IFF_POINTOPOINT | IFF_NOARP;
+	ndev->netdev_ops = &mhi_mbim_ndo;
+	ndev->mtu = MHI_MBIM_DEFAULT_MTU;
+	ndev->min_mtu = ETH_MIN_MTU;
+	ndev->max_mtu = MHI_MAX_BUF_SZ - ndev->needed_headroom;
+	ndev->tx_queue_len = 1000;
+	ndev->needs_free_netdev = true;
+}
+
+static const struct wwan_ops mhi_mbim_wwan_ops = {
+	.priv_size = sizeof(struct mhi_mbim_link),
+	.setup = mhi_mbim_setup,
+	.newlink = mhi_mbim_newlink,
+	.dellink = mhi_mbim_dellink,
+};
+
+static int mhi_mbim_probe(struct mhi_device *mhi_dev, const struct mhi_device_id *id)
+{
+	struct mhi_controller *cntrl = mhi_dev->mhi_cntrl;
+	struct mhi_mbim_context *mbim;
+	int err;
+
+	mbim = devm_kzalloc(&mhi_dev->dev, sizeof(*mbim), GFP_KERNEL);
+	if (!mbim)
+		return -ENOMEM;
+
+	spin_lock_init(&mbim->tx_lock);
+	dev_set_drvdata(&mhi_dev->dev, mbim);
+	mbim->mdev = mhi_dev;
+	mbim->mru = mhi_dev->mhi_cntrl->mru ? mhi_dev->mhi_cntrl->mru : MHI_DEFAULT_MRU;
+
+	INIT_DELAYED_WORK(&mbim->rx_refill, mhi_net_rx_refill_work);
+
+	/* Start MHI channels */
+	err = mhi_prepare_for_transfer(mhi_dev);
+	if (err)
+		return err;
+
+	/* Number of transfer descriptors determines size of the queue */
+	mbim->rx_queue_sz = mhi_get_free_desc_count(mhi_dev, DMA_FROM_DEVICE);
+
+	/* Register wwan link ops with MHI controller representing WWAN instance */
+	return wwan_register_ops(&cntrl->mhi_dev->dev, &mhi_mbim_wwan_ops, mbim, 0);
+}
+
+static void mhi_mbim_remove(struct mhi_device *mhi_dev)
+{
+	struct mhi_mbim_context *mbim = dev_get_drvdata(&mhi_dev->dev);
+	struct mhi_controller *cntrl = mhi_dev->mhi_cntrl;
+
+	mhi_unprepare_from_transfer(mhi_dev);
+	cancel_delayed_work_sync(&mbim->rx_refill);
+	wwan_unregister_ops(&cntrl->mhi_dev->dev);
+	kfree_skb(mbim->skbagg_head);
+	dev_set_drvdata(&mhi_dev->dev, NULL);
+}
+
+static const struct mhi_device_id mhi_mbim_id_table[] = {
+	/* Hardware accelerated data PATH (to modem IPA), MBIM protocol */
+	{ .chan = "IP_HW0_MBIM", .driver_data = 0 },
+	{}
+};
+MODULE_DEVICE_TABLE(mhi, mhi_mbim_id_table);
+
+static struct mhi_driver mhi_mbim_driver = {
+	.probe = mhi_mbim_probe,
+	.remove = mhi_mbim_remove,
+	.dl_xfer_cb = mhi_mbim_dl_callback,
+	.ul_xfer_cb = mhi_mbim_ul_callback,
+	.id_table = mhi_mbim_id_table,
+	.driver = {
+		.name = "mhi_wwan_mbim",
+		.owner = THIS_MODULE,
+	},
+};
+
+module_mhi_driver(mhi_mbim_driver);
+
+MODULE_AUTHOR("Loic Poulain <loic.poulain@linaro.org>");
+MODULE_DESCRIPTION("Network/MBIM over MHI");
+MODULE_LICENSE("GPL v2");