// SPDX-License-Identifier: GPL-2.0-or-later
/* MHI MBIM Network driver - Network/MBIM over MHI bus
*
* Copyright (C) 2021 Linaro Ltd <[email protected]>
*
* 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 <[email protected]>
*
*/
#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)
#define WDS_BIND_MUX_DATA_PORT_MUX_ID 112
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 int mhi_mbim_get_link_mux_id(struct mhi_controller *cntrl)
{
if (strcmp(cntrl->name, "foxconn-dw5934e") == 0 ||
strcmp(cntrl->name, "foxconn-t99w515") == 0)
return WDS_BIND_MUX_DATA_PORT_MUX_ID;
return 0;
}
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(&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(&link->rx_syncp, start));
do {
start = u64_stats_fetch_begin(&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(&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, link_id;
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);
/* Get the corresponding mux_id from mhi */
link_id = mhi_mbim_get_link_mux_id(cntrl);
/* Register wwan link ops with MHI controller representing WWAN instance */
return wwan_register_ops(&cntrl->mhi_dev->dev, &mhi_mbim_wwan_ops, mbim, link_id);
}
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",
},
};
module_mhi_driver(mhi_mbim_driver);
MODULE_AUTHOR("Loic Poulain <[email protected]>");
MODULE_DESCRIPTION("Network/MBIM over MHI");
MODULE_LICENSE("GPL v2");
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