net: mhi: Remove MBIM protocol
authorLoic Poulain <loic.poulain@linaro.org>
Tue, 3 Aug 2021 13:36:29 +0000 (15:36 +0200)
committerDavid S. Miller <davem@davemloft.net>
Wed, 4 Aug 2021 09:10:12 +0000 (10:10 +0100)
The MBIM protocol has now been integrated in a proper WWAN driver. We
can then revert back to a simpler driver for mhi_net, which is used
for raw IP or QMAP protocol (via rmnet link).

- Remove protocol management
- Remove WWAN framework usage (only valid for mbim)
- Remove net/mhi directory for simpler mhi_net.c file

Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/Kconfig
drivers/net/Makefile
drivers/net/mhi/Makefile [deleted file]
drivers/net/mhi/mhi.h [deleted file]
drivers/net/mhi/net.c [deleted file]
drivers/net/mhi/proto_mbim.c [deleted file]
drivers/net/mhi_net.c [new file with mode: 0644]

index c8b4eea..995c613 100644 (file)
@@ -431,10 +431,10 @@ config VSOCKMON
 config MHI_NET
        tristate "MHI network driver"
        depends on MHI_BUS
-       select WWAN
        help
          This is the network driver for MHI bus.  It can be used with
-         QCOM based WWAN modems (like SDX55).  Say Y or M.
+         QCOM based WWAN modems for IP or QMAP/rmnet protocol (like SDX55).
+         Say Y or M.
 
 endif # NET_CORE
 
index 6701211..7398386 100644 (file)
@@ -37,7 +37,7 @@ obj-$(CONFIG_GTP) += gtp.o
 obj-$(CONFIG_NLMON) += nlmon.o
 obj-$(CONFIG_NET_VRF) += vrf.o
 obj-$(CONFIG_VSOCKMON) += vsockmon.o
-obj-$(CONFIG_MHI_NET) += mhi/
+obj-$(CONFIG_MHI_NET) += mhi_net.o
 
 #
 # Networking Drivers
diff --git a/drivers/net/mhi/Makefile b/drivers/net/mhi/Makefile
deleted file mode 100644 (file)
index f71b9f8..0000000
+++ /dev/null
@@ -1,3 +0,0 @@
-obj-$(CONFIG_MHI_NET) += mhi_net.o
-
-mhi_net-y := net.o proto_mbim.o
diff --git a/drivers/net/mhi/mhi.h b/drivers/net/mhi/mhi.h
deleted file mode 100644 (file)
index 1d0c499..0000000
+++ /dev/null
@@ -1,41 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-/* MHI Network driver - Network over MHI bus
- *
- * Copyright (C) 2021 Linaro Ltd <loic.poulain@linaro.org>
- */
-
-struct mhi_net_stats {
-       u64_stats_t rx_packets;
-       u64_stats_t rx_bytes;
-       u64_stats_t rx_errors;
-       u64_stats_t rx_dropped;
-       u64_stats_t rx_length_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 mhi_net_dev {
-       struct mhi_device *mdev;
-       struct net_device *ndev;
-       struct sk_buff *skbagg_head;
-       struct sk_buff *skbagg_tail;
-       const struct mhi_net_proto *proto;
-       void *proto_data;
-       struct delayed_work rx_refill;
-       struct mhi_net_stats stats;
-       u32 rx_queue_sz;
-       int msg_enable;
-       unsigned int mru;
-};
-
-struct mhi_net_proto {
-       int (*init)(struct mhi_net_dev *mhi_netdev);
-       struct sk_buff * (*tx_fixup)(struct mhi_net_dev *mhi_netdev, struct sk_buff *skb);
-       void (*rx)(struct mhi_net_dev *mhi_netdev, struct sk_buff *skb);
-};
-
-extern const struct mhi_net_proto proto_mbim;
diff --git a/drivers/net/mhi/net.c b/drivers/net/mhi/net.c
deleted file mode 100644 (file)
index 0cc7dcd..0000000
+++ /dev/null
@@ -1,487 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/* MHI Network driver - Network over MHI bus
- *
- * Copyright (C) 2020 Linaro Ltd <loic.poulain@linaro.org>
- */
-
-#include <linux/if_arp.h>
-#include <linux/mhi.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/wwan.h>
-
-#include "mhi.h"
-
-#define MHI_NET_MIN_MTU                ETH_MIN_MTU
-#define MHI_NET_MAX_MTU                0xffff
-#define MHI_NET_DEFAULT_MTU    0x4000
-
-/* When set to false, the default netdev (link 0) is not created, and it's up
- * to user to create the link (via wwan rtnetlink).
- */
-static bool create_default_iface = true;
-module_param(create_default_iface, bool, 0);
-
-struct mhi_device_info {
-       const char *netname;
-       const struct mhi_net_proto *proto;
-};
-
-static int mhi_ndo_open(struct net_device *ndev)
-{
-       struct mhi_net_dev *mhi_netdev = wwan_netdev_drvpriv(ndev);
-
-       /* Feed the rx buffer pool */
-       schedule_delayed_work(&mhi_netdev->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_ndo_stop(struct net_device *ndev)
-{
-       struct mhi_net_dev *mhi_netdev = wwan_netdev_drvpriv(ndev);
-
-       netif_stop_queue(ndev);
-       netif_carrier_off(ndev);
-       cancel_delayed_work_sync(&mhi_netdev->rx_refill);
-
-       return 0;
-}
-
-static netdev_tx_t mhi_ndo_xmit(struct sk_buff *skb, struct net_device *ndev)
-{
-       struct mhi_net_dev *mhi_netdev = wwan_netdev_drvpriv(ndev);
-       const struct mhi_net_proto *proto = mhi_netdev->proto;
-       struct mhi_device *mdev = mhi_netdev->mdev;
-       int err;
-
-       if (proto && proto->tx_fixup) {
-               skb = proto->tx_fixup(mhi_netdev, skb);
-               if (unlikely(!skb))
-                       goto exit_drop;
-       }
-
-       err = mhi_queue_skb(mdev, DMA_TO_DEVICE, skb, skb->len, MHI_EOT);
-       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;
-       }
-
-       if (mhi_queue_is_full(mdev, DMA_TO_DEVICE))
-               netif_stop_queue(ndev);
-
-       return NETDEV_TX_OK;
-
-exit_drop:
-       u64_stats_update_begin(&mhi_netdev->stats.tx_syncp);
-       u64_stats_inc(&mhi_netdev->stats.tx_dropped);
-       u64_stats_update_end(&mhi_netdev->stats.tx_syncp);
-
-       return NETDEV_TX_OK;
-}
-
-static void mhi_ndo_get_stats64(struct net_device *ndev,
-                               struct rtnl_link_stats64 *stats)
-{
-       struct mhi_net_dev *mhi_netdev = wwan_netdev_drvpriv(ndev);
-       unsigned int start;
-
-       do {
-               start = u64_stats_fetch_begin_irq(&mhi_netdev->stats.rx_syncp);
-               stats->rx_packets = u64_stats_read(&mhi_netdev->stats.rx_packets);
-               stats->rx_bytes = u64_stats_read(&mhi_netdev->stats.rx_bytes);
-               stats->rx_errors = u64_stats_read(&mhi_netdev->stats.rx_errors);
-               stats->rx_dropped = u64_stats_read(&mhi_netdev->stats.rx_dropped);
-               stats->rx_length_errors = u64_stats_read(&mhi_netdev->stats.rx_length_errors);
-       } while (u64_stats_fetch_retry_irq(&mhi_netdev->stats.rx_syncp, start));
-
-       do {
-               start = u64_stats_fetch_begin_irq(&mhi_netdev->stats.tx_syncp);
-               stats->tx_packets = u64_stats_read(&mhi_netdev->stats.tx_packets);
-               stats->tx_bytes = u64_stats_read(&mhi_netdev->stats.tx_bytes);
-               stats->tx_errors = u64_stats_read(&mhi_netdev->stats.tx_errors);
-               stats->tx_dropped = u64_stats_read(&mhi_netdev->stats.tx_dropped);
-       } while (u64_stats_fetch_retry_irq(&mhi_netdev->stats.tx_syncp, start));
-}
-
-static const struct net_device_ops mhi_netdev_ops = {
-       .ndo_open               = mhi_ndo_open,
-       .ndo_stop               = mhi_ndo_stop,
-       .ndo_start_xmit         = mhi_ndo_xmit,
-       .ndo_get_stats64        = mhi_ndo_get_stats64,
-};
-
-static void mhi_net_setup(struct net_device *ndev)
-{
-       ndev->header_ops = NULL;  /* No header */
-       ndev->type = ARPHRD_RAWIP;
-       ndev->hard_header_len = 0;
-       ndev->addr_len = 0;
-       ndev->flags = IFF_POINTOPOINT | IFF_NOARP;
-       ndev->netdev_ops = &mhi_netdev_ops;
-       ndev->mtu = MHI_NET_DEFAULT_MTU;
-       ndev->min_mtu = MHI_NET_MIN_MTU;
-       ndev->max_mtu = MHI_NET_MAX_MTU;
-       ndev->tx_queue_len = 1000;
-}
-
-static struct sk_buff *mhi_net_skb_agg(struct mhi_net_dev *mhi_netdev,
-                                      struct sk_buff *skb)
-{
-       struct sk_buff *head = mhi_netdev->skbagg_head;
-       struct sk_buff *tail = mhi_netdev->skbagg_tail;
-
-       /* This is non-paged skb chaining using frag_list */
-       if (!head) {
-               mhi_netdev->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;
-
-       mhi_netdev->skbagg_tail = skb;
-
-       return mhi_netdev->skbagg_head;
-}
-
-static void mhi_net_dl_callback(struct mhi_device *mhi_dev,
-                               struct mhi_result *mhi_res)
-{
-       struct mhi_net_dev *mhi_netdev = dev_get_drvdata(&mhi_dev->dev);
-       const struct mhi_net_proto *proto = mhi_netdev->proto;
-       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 can not fit in one MHI buffer and has been
-                        * split over multiple MHI transfers, do re-aggregation.
-                        * That usually means the device side MTU is larger than
-                        * the host side MTU/MRU. Since this is not optimal,
-                        * print a warning (once).
-                        */
-                       netdev_warn_once(mhi_netdev->ndev,
-                                        "Fragmented packets received, fix MTU?\n");
-                       skb_put(skb, mhi_res->bytes_xferd);
-                       mhi_net_skb_agg(mhi_netdev, 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);
-                       u64_stats_update_begin(&mhi_netdev->stats.rx_syncp);
-                       u64_stats_inc(&mhi_netdev->stats.rx_errors);
-                       u64_stats_update_end(&mhi_netdev->stats.rx_syncp);
-               }
-       } else {
-               skb_put(skb, mhi_res->bytes_xferd);
-
-               if (mhi_netdev->skbagg_head) {
-                       /* Aggregate the final fragment */
-                       skb = mhi_net_skb_agg(mhi_netdev, skb);
-                       mhi_netdev->skbagg_head = NULL;
-               }
-
-               switch (skb->data[0] & 0xf0) {
-               case 0x40:
-                       skb->protocol = htons(ETH_P_IP);
-                       break;
-               case 0x60:
-                       skb->protocol = htons(ETH_P_IPV6);
-                       break;
-               default:
-                       skb->protocol = htons(ETH_P_MAP);
-                       break;
-               }
-
-               if (proto && proto->rx) {
-                       proto->rx(mhi_netdev, skb);
-               } else {
-                       u64_stats_update_begin(&mhi_netdev->stats.rx_syncp);
-                       u64_stats_inc(&mhi_netdev->stats.rx_packets);
-                       u64_stats_add(&mhi_netdev->stats.rx_bytes, skb->len);
-                       u64_stats_update_end(&mhi_netdev->stats.rx_syncp);
-                       netif_rx(skb);
-               }
-       }
-
-       /* Refill if RX buffers queue becomes low */
-       if (free_desc_count >= mhi_netdev->rx_queue_sz / 2)
-               schedule_delayed_work(&mhi_netdev->rx_refill, 0);
-}
-
-static void mhi_net_ul_callback(struct mhi_device *mhi_dev,
-                               struct mhi_result *mhi_res)
-{
-       struct mhi_net_dev *mhi_netdev = dev_get_drvdata(&mhi_dev->dev);
-       struct net_device *ndev = mhi_netdev->ndev;
-       struct mhi_device *mdev = mhi_netdev->mdev;
-       struct sk_buff *skb = mhi_res->buf_addr;
-
-       /* 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(&mhi_netdev->stats.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(&mhi_netdev->stats.tx_syncp);
-                       return;
-               }
-
-               u64_stats_inc(&mhi_netdev->stats.tx_errors);
-       } else {
-               u64_stats_inc(&mhi_netdev->stats.tx_packets);
-               u64_stats_add(&mhi_netdev->stats.tx_bytes, mhi_res->bytes_xferd);
-       }
-       u64_stats_update_end(&mhi_netdev->stats.tx_syncp);
-
-       if (netif_queue_stopped(ndev) && !mhi_queue_is_full(mdev, DMA_TO_DEVICE))
-               netif_wake_queue(ndev);
-}
-
-static void mhi_net_rx_refill_work(struct work_struct *work)
-{
-       struct mhi_net_dev *mhi_netdev = container_of(work, struct mhi_net_dev,
-                                                     rx_refill.work);
-       struct net_device *ndev = mhi_netdev->ndev;
-       struct mhi_device *mdev = mhi_netdev->mdev;
-       struct sk_buff *skb;
-       unsigned int size;
-       int err;
-
-       size = mhi_netdev->mru ? mhi_netdev->mru : READ_ONCE(ndev->mtu);
-
-       while (!mhi_queue_is_full(mdev, DMA_FROM_DEVICE)) {
-               skb = netdev_alloc_skb(ndev, size);
-               if (unlikely(!skb))
-                       break;
-
-               err = mhi_queue_skb(mdev, DMA_FROM_DEVICE, skb, size, MHI_EOT);
-               if (unlikely(err)) {
-                       net_err_ratelimited("%s: Failed to queue RX buf (%d)\n",
-                                           ndev->name, 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) == mhi_netdev->rx_queue_sz)
-               schedule_delayed_work(&mhi_netdev->rx_refill, HZ / 2);
-}
-
-static int mhi_net_newlink(void *ctxt, struct net_device *ndev, u32 if_id,
-                          struct netlink_ext_ack *extack)
-{
-       const struct mhi_device_info *info;
-       struct mhi_device *mhi_dev = ctxt;
-       struct mhi_net_dev *mhi_netdev;
-       int err;
-
-       info = (struct mhi_device_info *)mhi_dev->id->driver_data;
-
-       /* For now we only support one link (link context 0), driver must be
-        * reworked to break 1:1 relationship for net MBIM and to forward setup
-        * call to rmnet(QMAP) otherwise.
-        */
-       if (if_id != 0)
-               return -EINVAL;
-
-       if (dev_get_drvdata(&mhi_dev->dev))
-               return -EBUSY;
-
-       mhi_netdev = wwan_netdev_drvpriv(ndev);
-
-       dev_set_drvdata(&mhi_dev->dev, mhi_netdev);
-       mhi_netdev->ndev = ndev;
-       mhi_netdev->mdev = mhi_dev;
-       mhi_netdev->skbagg_head = NULL;
-       mhi_netdev->proto = info->proto;
-       mhi_netdev->mru = mhi_dev->mhi_cntrl->mru;
-
-       INIT_DELAYED_WORK(&mhi_netdev->rx_refill, mhi_net_rx_refill_work);
-       u64_stats_init(&mhi_netdev->stats.rx_syncp);
-       u64_stats_init(&mhi_netdev->stats.tx_syncp);
-
-       /* Start MHI channels */
-       err = mhi_prepare_for_transfer(mhi_dev);
-       if (err)
-               goto out_err;
-
-       /* Number of transfer descriptors determines size of the queue */
-       mhi_netdev->rx_queue_sz = mhi_get_free_desc_count(mhi_dev, DMA_FROM_DEVICE);
-
-       if (extack)
-               err = register_netdevice(ndev);
-       else
-               err = register_netdev(ndev);
-       if (err)
-               goto out_err;
-
-       if (mhi_netdev->proto) {
-               err = mhi_netdev->proto->init(mhi_netdev);
-               if (err)
-                       goto out_err_proto;
-       }
-
-       return 0;
-
-out_err_proto:
-       unregister_netdevice(ndev);
-out_err:
-       free_netdev(ndev);
-       return err;
-}
-
-static void mhi_net_dellink(void *ctxt, struct net_device *ndev,
-                           struct list_head *head)
-{
-       struct mhi_net_dev *mhi_netdev = wwan_netdev_drvpriv(ndev);
-       struct mhi_device *mhi_dev = ctxt;
-
-       if (head)
-               unregister_netdevice_queue(ndev, head);
-       else
-               unregister_netdev(ndev);
-
-       mhi_unprepare_from_transfer(mhi_dev);
-
-       kfree_skb(mhi_netdev->skbagg_head);
-
-       dev_set_drvdata(&mhi_dev->dev, NULL);
-}
-
-static const struct wwan_ops mhi_wwan_ops = {
-       .priv_size = sizeof(struct mhi_net_dev),
-       .setup = mhi_net_setup,
-       .newlink = mhi_net_newlink,
-       .dellink = mhi_net_dellink,
-};
-
-static int mhi_net_probe(struct mhi_device *mhi_dev,
-                        const struct mhi_device_id *id)
-{
-       const struct mhi_device_info *info = (struct mhi_device_info *)id->driver_data;
-       struct mhi_controller *cntrl = mhi_dev->mhi_cntrl;
-       struct net_device *ndev;
-       int err;
-
-       err = wwan_register_ops(&cntrl->mhi_dev->dev, &mhi_wwan_ops, mhi_dev,
-                               WWAN_NO_DEFAULT_LINK);
-       if (err)
-               return err;
-
-       if (!create_default_iface)
-               return 0;
-
-       /* Create a default interface which is used as either RMNET real-dev,
-        * MBIM link 0 or ip link 0)
-        */
-       ndev = alloc_netdev(sizeof(struct mhi_net_dev), info->netname,
-                           NET_NAME_PREDICTABLE, mhi_net_setup);
-       if (!ndev) {
-               err = -ENOMEM;
-               goto err_unregister;
-       }
-
-       SET_NETDEV_DEV(ndev, &mhi_dev->dev);
-
-       err = mhi_net_newlink(mhi_dev, ndev, 0, NULL);
-       if (err)
-               goto err_release;
-
-       return 0;
-
-err_release:
-       free_netdev(ndev);
-err_unregister:
-       wwan_unregister_ops(&cntrl->mhi_dev->dev);
-
-       return err;
-}
-
-static void mhi_net_remove(struct mhi_device *mhi_dev)
-{
-       struct mhi_net_dev *mhi_netdev = dev_get_drvdata(&mhi_dev->dev);
-       struct mhi_controller *cntrl = mhi_dev->mhi_cntrl;
-
-       /* WWAN core takes care of removing remaining links */
-       wwan_unregister_ops(&cntrl->mhi_dev->dev);
-
-       if (create_default_iface)
-               mhi_net_dellink(mhi_dev, mhi_netdev->ndev, NULL);
-}
-
-static const struct mhi_device_info mhi_hwip0 = {
-       .netname = "mhi_hwip%d",
-};
-
-static const struct mhi_device_info mhi_swip0 = {
-       .netname = "mhi_swip%d",
-};
-
-static const struct mhi_device_info mhi_hwip0_mbim = {
-       .netname = "mhi_mbim%d",
-       .proto = &proto_mbim,
-};
-
-static const struct mhi_device_id mhi_net_id_table[] = {
-       /* Hardware accelerated data PATH (to modem IPA), protocol agnostic */
-       { .chan = "IP_HW0", .driver_data = (kernel_ulong_t)&mhi_hwip0 },
-       /* Software data PATH (to modem CPU) */
-       { .chan = "IP_SW0", .driver_data = (kernel_ulong_t)&mhi_swip0 },
-       /* Hardware accelerated data PATH (to modem IPA), MBIM protocol */
-       { .chan = "IP_HW0_MBIM", .driver_data = (kernel_ulong_t)&mhi_hwip0_mbim },
-       {}
-};
-MODULE_DEVICE_TABLE(mhi, mhi_net_id_table);
-
-static struct mhi_driver mhi_net_driver = {
-       .probe = mhi_net_probe,
-       .remove = mhi_net_remove,
-       .dl_xfer_cb = mhi_net_dl_callback,
-       .ul_xfer_cb = mhi_net_ul_callback,
-       .id_table = mhi_net_id_table,
-       .driver = {
-               .name = "mhi_net",
-               .owner = THIS_MODULE,
-       },
-};
-
-module_mhi_driver(mhi_net_driver);
-
-MODULE_AUTHOR("Loic Poulain <loic.poulain@linaro.org>");
-MODULE_DESCRIPTION("Network over MHI");
-MODULE_LICENSE("GPL v2");
diff --git a/drivers/net/mhi/proto_mbim.c b/drivers/net/mhi/proto_mbim.c
deleted file mode 100644 (file)
index 761d90b..0000000
+++ /dev/null
@@ -1,310 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/* MHI Network driver - Network 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_vlan.h>
-#include <linux/ip.h>
-#include <linux/mii.h>
-#include <linux/netdevice.h>
-#include <linux/wwan.h>
-#include <linux/skbuff.h>
-#include <linux/usb.h>
-#include <linux/usb/cdc.h>
-#include <linux/usb/usbnet.h>
-#include <linux/usb/cdc_ncm.h>
-
-#include "mhi.h"
-
-#define MBIM_NDP16_SIGN_MASK 0x00ffffff
-
-/* Usual WWAN MTU */
-#define MHI_MBIM_DEFAULT_MTU 1500
-
-/* 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_MBIM_DEFAULT_MRU 3500
-
-struct mbim_context {
-       u16 rx_seq;
-       u16 tx_seq;
-};
-
-static void __mbim_length_errors_inc(struct mhi_net_dev *dev)
-{
-       u64_stats_update_begin(&dev->stats.rx_syncp);
-       u64_stats_inc(&dev->stats.rx_length_errors);
-       u64_stats_update_end(&dev->stats.rx_syncp);
-}
-
-static void __mbim_errors_inc(struct mhi_net_dev *dev)
-{
-       u64_stats_update_begin(&dev->stats.rx_syncp);
-       u64_stats_inc(&dev->stats.rx_errors);
-       u64_stats_update_end(&dev->stats.rx_syncp);
-}
-
-static int mbim_rx_verify_nth16(struct sk_buff *skb)
-{
-       struct mhi_net_dev *dev = wwan_netdev_drvpriv(skb->dev);
-       struct mbim_context *ctx = dev->proto_data;
-       struct usb_cdc_ncm_nth16 *nth16;
-       int len;
-
-       if (skb->len < sizeof(struct usb_cdc_ncm_nth16) +
-                       sizeof(struct usb_cdc_ncm_ndp16)) {
-               netif_dbg(dev, rx_err, dev->ndev, "frame too short\n");
-               __mbim_length_errors_inc(dev);
-               return -EINVAL;
-       }
-
-       nth16 = (struct usb_cdc_ncm_nth16 *)skb->data;
-
-       if (nth16->dwSignature != cpu_to_le32(USB_CDC_NCM_NTH16_SIGN)) {
-               netif_dbg(dev, rx_err, dev->ndev,
-                         "invalid NTH16 signature <%#010x>\n",
-                         le32_to_cpu(nth16->dwSignature));
-               __mbim_errors_inc(dev);
-               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) {
-               netif_dbg(dev, rx_err, dev->ndev,
-                         "NTB does not fit into the skb %u/%u\n", len,
-                         skb->len);
-               __mbim_length_errors_inc(dev);
-               return -EINVAL;
-       }
-
-       if (ctx->rx_seq + 1 != le16_to_cpu(nth16->wSequence) &&
-           (ctx->rx_seq || le16_to_cpu(nth16->wSequence)) &&
-           !(ctx->rx_seq == 0xffff && !le16_to_cpu(nth16->wSequence))) {
-               netif_dbg(dev, rx_err, dev->ndev,
-                         "sequence number glitch prev=%d curr=%d\n",
-                         ctx->rx_seq, le16_to_cpu(nth16->wSequence));
-       }
-       ctx->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)
-{
-       struct mhi_net_dev *dev = wwan_netdev_drvpriv(skb->dev);
-       int ret;
-
-       if (le16_to_cpu(ndp16->wLength) < USB_CDC_NCM_NDP16_LENGTH_MIN) {
-               netif_dbg(dev, rx_err, dev->ndev, "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) {
-               netif_dbg(dev, rx_err, dev->ndev,
-                         "Invalid nframes = %d\n", ret);
-               return -EINVAL;
-       }
-
-       return ret;
-}
-
-static void mbim_rx(struct mhi_net_dev *mhi_netdev, struct sk_buff *skb)
-{
-       struct net_device *ndev = mhi_netdev->ndev;
-       int ndpoffset;
-
-       /* Check NTB header and retrieve first NDP offset */
-       ndpoffset = mbim_rx_verify_nth16(skb);
-       if (ndpoffset < 0) {
-               net_err_ratelimited("%s: Incorrect NTB header\n", ndev->name);
-               goto error;
-       }
-
-       /* Process each NDP */
-       while (1) {
-               struct usb_cdc_ncm_ndp16 ndp16;
-               struct usb_cdc_ncm_dpe16 dpe16;
-               int nframes, n, dpeoffset;
-
-               if (skb_copy_bits(skb, ndpoffset, &ndp16, sizeof(ndp16))) {
-                       net_err_ratelimited("%s: Incorrect NDP offset (%u)\n",
-                                           ndev->name, ndpoffset);
-                       __mbim_length_errors_inc(mhi_netdev);
-                       goto error;
-               }
-
-               /* Check NDP header and retrieve number of datagrams */
-               nframes = mbim_rx_verify_ndp16(skb, &ndp16);
-               if (nframes < 0) {
-                       net_err_ratelimited("%s: Incorrect NDP16\n", ndev->name);
-                       __mbim_length_errors_inc(mhi_netdev);
-                       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("%s: Unsupported NDP type\n", ndev->name);
-                       __mbim_errors_inc(mhi_netdev);
-                       goto next_ndp;
-               }
-
-               /* Only primary IP session 0 (0x00) supported for now */
-               if (ndp16.dwSignature & ~cpu_to_le32(MBIM_NDP16_SIGN_MASK)) {
-                       net_err_ratelimited("%s: bad packet session\n", ndev->name);
-                       __mbim_errors_inc(mhi_netdev);
-                       goto next_ndp;
-               }
-
-               /* 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(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",
-                                                   ndev->name);
-                               __mbim_errors_inc(mhi_netdev);
-                               dev_kfree_skb_any(skbn);
-                               continue;
-                       }
-
-                       u64_stats_update_begin(&mhi_netdev->stats.rx_syncp);
-                       u64_stats_inc(&mhi_netdev->stats.rx_packets);
-                       u64_stats_add(&mhi_netdev->stats.rx_bytes, skbn->len);
-                       u64_stats_update_end(&mhi_netdev->stats.rx_syncp);
-                       netif_rx(skbn);
-               }
-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);
-}
-
-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 sk_buff *mbim_tx_fixup(struct mhi_net_dev *mhi_netdev,
-                                    struct sk_buff *skb)
-{
-       struct mbim_context *ctx = mhi_netdev->proto_data;
-       unsigned int dgram_size = skb->len;
-       struct usb_cdc_ncm_nth16 *nth16;
-       struct usb_cdc_ncm_ndp16 *ndp16;
-       struct mbim_tx_hdr *mbim_hdr;
-
-       /* For now, this is a partial implementation of CDC MBIM, 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(ctx->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);
-       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 int mbim_init(struct mhi_net_dev *mhi_netdev)
-{
-       struct net_device *ndev = mhi_netdev->ndev;
-
-       mhi_netdev->proto_data = devm_kzalloc(&ndev->dev,
-                                             sizeof(struct mbim_context),
-                                             GFP_KERNEL);
-       if (!mhi_netdev->proto_data)
-               return -ENOMEM;
-
-       ndev->needed_headroom = sizeof(struct mbim_tx_hdr);
-       ndev->mtu = MHI_MBIM_DEFAULT_MTU;
-
-       if (!mhi_netdev->mru)
-               mhi_netdev->mru = MHI_MBIM_DEFAULT_MRU;
-
-       return 0;
-}
-
-const struct mhi_net_proto proto_mbim = {
-       .init = mbim_init,
-       .rx = mbim_rx,
-       .tx_fixup = mbim_tx_fixup,
-};
diff --git a/drivers/net/mhi_net.c b/drivers/net/mhi_net.c
new file mode 100644 (file)
index 0000000..d127eb6
--- /dev/null
@@ -0,0 +1,416 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* MHI Network driver - Network over MHI bus
+ *
+ * Copyright (C) 2020 Linaro Ltd <loic.poulain@linaro.org>
+ */
+
+#include <linux/if_arp.h>
+#include <linux/mhi.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <linux/u64_stats_sync.h>
+
+#define MHI_NET_MIN_MTU                ETH_MIN_MTU
+#define MHI_NET_MAX_MTU                0xffff
+#define MHI_NET_DEFAULT_MTU    0x4000
+
+struct mhi_net_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 mhi_net_dev {
+       struct mhi_device *mdev;
+       struct net_device *ndev;
+       struct sk_buff *skbagg_head;
+       struct sk_buff *skbagg_tail;
+       struct delayed_work rx_refill;
+       struct mhi_net_stats stats;
+       u32 rx_queue_sz;
+       int msg_enable;
+       unsigned int mru;
+};
+
+struct mhi_device_info {
+       const char *netname;
+};
+
+static int mhi_ndo_open(struct net_device *ndev)
+{
+       struct mhi_net_dev *mhi_netdev = netdev_priv(ndev);
+
+       /* Feed the rx buffer pool */
+       schedule_delayed_work(&mhi_netdev->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_ndo_stop(struct net_device *ndev)
+{
+       struct mhi_net_dev *mhi_netdev = netdev_priv(ndev);
+
+       netif_stop_queue(ndev);
+       netif_carrier_off(ndev);
+       cancel_delayed_work_sync(&mhi_netdev->rx_refill);
+
+       return 0;
+}
+
+static netdev_tx_t mhi_ndo_xmit(struct sk_buff *skb, struct net_device *ndev)
+{
+       struct mhi_net_dev *mhi_netdev = netdev_priv(ndev);
+       struct mhi_device *mdev = mhi_netdev->mdev;
+       int err;
+
+       err = mhi_queue_skb(mdev, DMA_TO_DEVICE, skb, skb->len, MHI_EOT);
+       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;
+       }
+
+       if (mhi_queue_is_full(mdev, DMA_TO_DEVICE))
+               netif_stop_queue(ndev);
+
+       return NETDEV_TX_OK;
+
+exit_drop:
+       u64_stats_update_begin(&mhi_netdev->stats.tx_syncp);
+       u64_stats_inc(&mhi_netdev->stats.tx_dropped);
+       u64_stats_update_end(&mhi_netdev->stats.tx_syncp);
+
+       return NETDEV_TX_OK;
+}
+
+static void mhi_ndo_get_stats64(struct net_device *ndev,
+                               struct rtnl_link_stats64 *stats)
+{
+       struct mhi_net_dev *mhi_netdev = netdev_priv(ndev);
+       unsigned int start;
+
+       do {
+               start = u64_stats_fetch_begin_irq(&mhi_netdev->stats.rx_syncp);
+               stats->rx_packets = u64_stats_read(&mhi_netdev->stats.rx_packets);
+               stats->rx_bytes = u64_stats_read(&mhi_netdev->stats.rx_bytes);
+               stats->rx_errors = u64_stats_read(&mhi_netdev->stats.rx_errors);
+       } while (u64_stats_fetch_retry_irq(&mhi_netdev->stats.rx_syncp, start));
+
+       do {
+               start = u64_stats_fetch_begin_irq(&mhi_netdev->stats.tx_syncp);
+               stats->tx_packets = u64_stats_read(&mhi_netdev->stats.tx_packets);
+               stats->tx_bytes = u64_stats_read(&mhi_netdev->stats.tx_bytes);
+               stats->tx_errors = u64_stats_read(&mhi_netdev->stats.tx_errors);
+               stats->tx_dropped = u64_stats_read(&mhi_netdev->stats.tx_dropped);
+       } while (u64_stats_fetch_retry_irq(&mhi_netdev->stats.tx_syncp, start));
+}
+
+static const struct net_device_ops mhi_netdev_ops = {
+       .ndo_open               = mhi_ndo_open,
+       .ndo_stop               = mhi_ndo_stop,
+       .ndo_start_xmit         = mhi_ndo_xmit,
+       .ndo_get_stats64        = mhi_ndo_get_stats64,
+};
+
+static void mhi_net_setup(struct net_device *ndev)
+{
+       ndev->header_ops = NULL;  /* No header */
+       ndev->type = ARPHRD_RAWIP;
+       ndev->hard_header_len = 0;
+       ndev->addr_len = 0;
+       ndev->flags = IFF_POINTOPOINT | IFF_NOARP;
+       ndev->netdev_ops = &mhi_netdev_ops;
+       ndev->mtu = MHI_NET_DEFAULT_MTU;
+       ndev->min_mtu = MHI_NET_MIN_MTU;
+       ndev->max_mtu = MHI_NET_MAX_MTU;
+       ndev->tx_queue_len = 1000;
+}
+
+static struct sk_buff *mhi_net_skb_agg(struct mhi_net_dev *mhi_netdev,
+                                      struct sk_buff *skb)
+{
+       struct sk_buff *head = mhi_netdev->skbagg_head;
+       struct sk_buff *tail = mhi_netdev->skbagg_tail;
+
+       /* This is non-paged skb chaining using frag_list */
+       if (!head) {
+               mhi_netdev->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;
+
+       mhi_netdev->skbagg_tail = skb;
+
+       return mhi_netdev->skbagg_head;
+}
+
+static void mhi_net_dl_callback(struct mhi_device *mhi_dev,
+                               struct mhi_result *mhi_res)
+{
+       struct mhi_net_dev *mhi_netdev = 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 can not fit in one MHI buffer and has been
+                        * split over multiple MHI transfers, do re-aggregation.
+                        * That usually means the device side MTU is larger than
+                        * the host side MTU/MRU. Since this is not optimal,
+                        * print a warning (once).
+                        */
+                       netdev_warn_once(mhi_netdev->ndev,
+                                        "Fragmented packets received, fix MTU?\n");
+                       skb_put(skb, mhi_res->bytes_xferd);
+                       mhi_net_skb_agg(mhi_netdev, 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);
+                       u64_stats_update_begin(&mhi_netdev->stats.rx_syncp);
+                       u64_stats_inc(&mhi_netdev->stats.rx_errors);
+                       u64_stats_update_end(&mhi_netdev->stats.rx_syncp);
+               }
+       } else {
+               skb_put(skb, mhi_res->bytes_xferd);
+
+               if (mhi_netdev->skbagg_head) {
+                       /* Aggregate the final fragment */
+                       skb = mhi_net_skb_agg(mhi_netdev, skb);
+                       mhi_netdev->skbagg_head = NULL;
+               }
+
+               switch (skb->data[0] & 0xf0) {
+               case 0x40:
+                       skb->protocol = htons(ETH_P_IP);
+                       break;
+               case 0x60:
+                       skb->protocol = htons(ETH_P_IPV6);
+                       break;
+               default:
+                       skb->protocol = htons(ETH_P_MAP);
+                       break;
+               }
+
+               u64_stats_update_begin(&mhi_netdev->stats.rx_syncp);
+               u64_stats_inc(&mhi_netdev->stats.rx_packets);
+               u64_stats_add(&mhi_netdev->stats.rx_bytes, skb->len);
+               u64_stats_update_end(&mhi_netdev->stats.rx_syncp);
+               netif_rx(skb);
+       }
+
+       /* Refill if RX buffers queue becomes low */
+       if (free_desc_count >= mhi_netdev->rx_queue_sz / 2)
+               schedule_delayed_work(&mhi_netdev->rx_refill, 0);
+}
+
+static void mhi_net_ul_callback(struct mhi_device *mhi_dev,
+                               struct mhi_result *mhi_res)
+{
+       struct mhi_net_dev *mhi_netdev = dev_get_drvdata(&mhi_dev->dev);
+       struct net_device *ndev = mhi_netdev->ndev;
+       struct mhi_device *mdev = mhi_netdev->mdev;
+       struct sk_buff *skb = mhi_res->buf_addr;
+
+       /* 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(&mhi_netdev->stats.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(&mhi_netdev->stats.tx_syncp);
+                       return;
+               }
+
+               u64_stats_inc(&mhi_netdev->stats.tx_errors);
+       } else {
+               u64_stats_inc(&mhi_netdev->stats.tx_packets);
+               u64_stats_add(&mhi_netdev->stats.tx_bytes, mhi_res->bytes_xferd);
+       }
+       u64_stats_update_end(&mhi_netdev->stats.tx_syncp);
+
+       if (netif_queue_stopped(ndev) && !mhi_queue_is_full(mdev, DMA_TO_DEVICE))
+               netif_wake_queue(ndev);
+}
+
+static void mhi_net_rx_refill_work(struct work_struct *work)
+{
+       struct mhi_net_dev *mhi_netdev = container_of(work, struct mhi_net_dev,
+                                                     rx_refill.work);
+       struct net_device *ndev = mhi_netdev->ndev;
+       struct mhi_device *mdev = mhi_netdev->mdev;
+       struct sk_buff *skb;
+       unsigned int size;
+       int err;
+
+       size = mhi_netdev->mru ? mhi_netdev->mru : READ_ONCE(ndev->mtu);
+
+       while (!mhi_queue_is_full(mdev, DMA_FROM_DEVICE)) {
+               skb = netdev_alloc_skb(ndev, size);
+               if (unlikely(!skb))
+                       break;
+
+               err = mhi_queue_skb(mdev, DMA_FROM_DEVICE, skb, size, MHI_EOT);
+               if (unlikely(err)) {
+                       net_err_ratelimited("%s: Failed to queue RX buf (%d)\n",
+                                           ndev->name, 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) == mhi_netdev->rx_queue_sz)
+               schedule_delayed_work(&mhi_netdev->rx_refill, HZ / 2);
+}
+
+static int mhi_net_newlink(struct mhi_device *mhi_dev, struct net_device *ndev)
+{
+       struct mhi_net_dev *mhi_netdev;
+       int err;
+
+       mhi_netdev = netdev_priv(ndev);
+
+       dev_set_drvdata(&mhi_dev->dev, mhi_netdev);
+       mhi_netdev->ndev = ndev;
+       mhi_netdev->mdev = mhi_dev;
+       mhi_netdev->skbagg_head = NULL;
+       mhi_netdev->mru = mhi_dev->mhi_cntrl->mru;
+
+       INIT_DELAYED_WORK(&mhi_netdev->rx_refill, mhi_net_rx_refill_work);
+       u64_stats_init(&mhi_netdev->stats.rx_syncp);
+       u64_stats_init(&mhi_netdev->stats.tx_syncp);
+
+       /* Start MHI channels */
+       err = mhi_prepare_for_transfer(mhi_dev);
+       if (err)
+               goto out_err;
+
+       /* Number of transfer descriptors determines size of the queue */
+       mhi_netdev->rx_queue_sz = mhi_get_free_desc_count(mhi_dev, DMA_FROM_DEVICE);
+
+       err = register_netdev(ndev);
+       if (err)
+               return err;
+
+       return 0;
+
+out_err:
+       free_netdev(ndev);
+       return err;
+}
+
+static void mhi_net_dellink(struct mhi_device *mhi_dev, struct net_device *ndev)
+{
+       struct mhi_net_dev *mhi_netdev = netdev_priv(ndev);
+
+       unregister_netdev(ndev);
+
+       mhi_unprepare_from_transfer(mhi_dev);
+
+       kfree_skb(mhi_netdev->skbagg_head);
+
+       dev_set_drvdata(&mhi_dev->dev, NULL);
+}
+
+static int mhi_net_probe(struct mhi_device *mhi_dev,
+                        const struct mhi_device_id *id)
+{
+       const struct mhi_device_info *info = (struct mhi_device_info *)id->driver_data;
+       struct net_device *ndev;
+       int err;
+
+       ndev = alloc_netdev(sizeof(struct mhi_net_dev), info->netname,
+                           NET_NAME_PREDICTABLE, mhi_net_setup);
+       if (!ndev)
+               return -ENOMEM;
+
+       SET_NETDEV_DEV(ndev, &mhi_dev->dev);
+
+       err = mhi_net_newlink(mhi_dev, ndev);
+       if (err) {
+               free_netdev(ndev);
+               return err;
+       }
+
+       return 0;
+}
+
+static void mhi_net_remove(struct mhi_device *mhi_dev)
+{
+       struct mhi_net_dev *mhi_netdev = dev_get_drvdata(&mhi_dev->dev);
+
+       mhi_net_dellink(mhi_dev, mhi_netdev->ndev);
+}
+
+static const struct mhi_device_info mhi_hwip0 = {
+       .netname = "mhi_hwip%d",
+};
+
+static const struct mhi_device_info mhi_swip0 = {
+       .netname = "mhi_swip%d",
+};
+
+static const struct mhi_device_id mhi_net_id_table[] = {
+       /* Hardware accelerated data PATH (to modem IPA), protocol agnostic */
+       { .chan = "IP_HW0", .driver_data = (kernel_ulong_t)&mhi_hwip0 },
+       /* Software data PATH (to modem CPU) */
+       { .chan = "IP_SW0", .driver_data = (kernel_ulong_t)&mhi_swip0 },
+       {}
+};
+MODULE_DEVICE_TABLE(mhi, mhi_net_id_table);
+
+static struct mhi_driver mhi_net_driver = {
+       .probe = mhi_net_probe,
+       .remove = mhi_net_remove,
+       .dl_xfer_cb = mhi_net_dl_callback,
+       .ul_xfer_cb = mhi_net_ul_callback,
+       .id_table = mhi_net_id_table,
+       .driver = {
+               .name = "mhi_net",
+               .owner = THIS_MODULE,
+       },
+};
+
+module_mhi_driver(mhi_net_driver);
+
+MODULE_AUTHOR("Loic Poulain <loic.poulain@linaro.org>");
+MODULE_DESCRIPTION("Network over MHI");
+MODULE_LICENSE("GPL v2");