#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/ethtool.h>
#include <linux/etherdevice.h>
#include <linux/mii.h>
#include <linux/usb.h>
#include <linux/usb/cdc.h>
#include <linux/usb/usbnet.h>
#include <linux/usb/cdc-wdm.h>
/*
This driver supports wwan (3G/LTE/?) devices
*/
/* driver specific data */
struct qmi_wwan_state {
struct usb_driver *subdriver;
atomic_t pmcount;
unsigned long unused;
struct usb_interface *control;
struct usb_interface *data;
};
/* default ethernet address used by the modem */
static const u8 default_modem_addr[ETH_ALEN] = {0x02, 0x50, 0xf3};
/* Make up an ethernet header if the packet doesn't have one.
*
* A firmware bug common among several devices cause them to send raw
* IP packets under some circumstances. There is no way for the
* driver/host to know when this will happen. And even when the bug
* hits, some packets will still arrive with an intact header.
*
* The supported devices are only capably of sending IPv4, IPv6 and
* ARP packets on a point-to-point link. Any packet with an ethernet
* header will have either our address or a broadcast/multicast
* address as destination. ARP packets will always have a header.
*
* This means that this function will reliably add the appropriate
* header iff necessary, provided our hardware address does not start
* with 4 or 6.
*
* Another common firmware bug results in all packets being addressed
* to 00:a0:c6:00:00:00 despite the host address being different.
* This function will also fixup such packets.
*/
static int qmi_wwan_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
{
__be16 proto;
/* This check is no longer done by usbnet */
if (skb->len < dev->net->hard_header_len)
return 0;
switch (skb->data[0] & 0xf0) {
case 0x40:
proto = htons(ETH_P_IP);
break;
case 0x60:
proto = htons(ETH_P_IPV6);
break;
case 0x00:
if (is_multicast_ether_addr(skb->data))
return 1;
/* possibly bogus destination - rewrite just in case */
skb_reset_mac_header(skb);
goto fix_dest;
default:
/* pass along other packets without modifications */
return 1;
}
if (skb_headroom(skb) < ETH_HLEN)
return 0;
skb_push(skb, ETH_HLEN);
skb_reset_mac_header(skb);
eth_hdr(skb)->h_proto = proto;
memset(eth_hdr(skb)->h_source, 0, ETH_ALEN);
fix_dest:
memcpy(eth_hdr(skb)->h_dest, dev->net->dev_addr, ETH_ALEN);
return 1;
}
/* very simplistic detection of IPv4 or IPv6 headers */
static bool possibly_iphdr(const char *data)
{
return (data[0] & 0xd0) == 0x40;
}
/* disallow addresses which may be confused with IP headers */
static int qmi_wwan_mac_addr(struct net_device *dev, void *p)
{
int ret;
struct sockaddr *addr = p;
ret = eth_prepare_mac_addr_change(dev, p);
if (ret < 0)
return ret;
if (possibly_iphdr(addr->sa_data))
return -EADDRNOTAVAIL;
eth_commit_mac_addr_change(dev, p);
return 0;
}
static const struct net_device_ops qmi_wwan_netdev_ops = {
.ndo_open = usbnet_open,
.ndo_stop = usbnet_stop,
.ndo_start_xmit = usbnet_start_xmit,
.ndo_tx_timeout = usbnet_tx_timeout,
.ndo_change_mtu = usbnet_change_mtu,
.ndo_set_mac_address = qmi_wwan_mac_addr,
.ndo_validate_addr = eth_validate_addr,
};
/* using a counter to merge subdriver requests with our own into a
* combined state
*/
static int qmi_wwan_manage_power(struct usbnet *dev, int on)
{
struct qmi_wwan_state *info = (void *)&dev->data;
int rv;
dev_dbg(&dev->intf->dev, "%s() pmcount=%d, on=%d\n", __func__,
atomic_read(&info->pmcount), on);
if ((on && atomic_add_return(1, &info->pmcount) == 1) ||
(!on && atomic_dec_and_test(&info->pmcount))) {
/* need autopm_get/put here to ensure the usbcore sees
* the new value
*/
rv = usb_autopm_get_interface(dev->intf);
dev->intf->needs_remote_wakeup = on;
if (!rv)
usb_autopm_put_interface(dev->intf);
}
return 0;
}
static int qmi_wwan_cdc_wdm_manage_power(struct usb_interface *intf, int on)
{
struct usbnet *dev = usb_get_intfdata(intf);
/* can be called while disconnecting */
if (!dev)
return 0;
return qmi_wwan_manage_power(dev, on);
}
/* collect all three endpoints and register subdriver */
static int qmi_wwan_register_subdriver(struct usbnet *dev)
{
int rv;
struct usb_driver *subdriver = NULL;
struct qmi_wwan_state *info = (void *)&dev->data;
/* collect bulk endpoints */
rv = usbnet_get_endpoints(dev, info->data);
if (rv < 0)
goto err;
/* update status endpoint if separate control interface */
if (info->control != info->data)
dev->status = &info->control->cur_altsetting->endpoint[0];
/* require interrupt endpoint for subdriver */
if (!dev->status) {
rv = -EINVAL;
goto err;
}
/* for subdriver power management */
atomic_set(&info->pmcount, 0);
/* register subdriver */
subdriver = usb_cdc_wdm_register(info->control, &dev->status->desc,
4096, &qmi_wwan_cdc_wdm_manage_power);
if (IS_ERR(subdriver)) {
dev_err(&info->control->dev, "subdriver registration failed\n");
rv = PTR_ERR(subdriver);
goto err;
}
/* prevent usbnet from using status endpoint */
dev->status = NULL;
/* save subdriver struct for suspend/resume wrappers */
info->subdriver = subdriver;
err:
return rv;
}
static int qmi_wwan_bind(struct usbnet *dev, struct usb_interface *intf)
{
int status = -1;
u8 *buf = intf->cur_altsetting->extra;
int len = intf->cur_altsetting->extralen;
struct usb_interface_descriptor *desc = &intf->cur_altsetting->desc;
struct usb_cdc_union_desc *cdc_union = NULL;
struct usb_cdc_ether_desc *cdc_ether = NULL;
u32 found = 0;
struct usb_driver *driver = driver_of(intf);
struct qmi_wwan_state *info = (void *)&dev->data;
BUILD_BUG_ON((sizeof(((struct usbnet *)0)->data) <
sizeof(struct qmi_wwan_state)));
/* set up initial state */
info->control = intf;
info->data = intf;
/* and a number of CDC descriptors */
while (len > 3) {
struct usb_descriptor_header *h = (void *)buf;
/* ignore any misplaced descriptors */
if (h->bDescriptorType != USB_DT_CS_INTERFACE)
goto next_desc;
/* buf[2] is CDC descriptor subtype */
switch (buf[2]) {
case USB_CDC_HEADER_TYPE:
if (found & 1 << USB_CDC_HEADER_TYPE) {
dev_dbg(&intf->dev, "extra CDC header\n");
goto err;
}
if (h->bLength != sizeof(struct usb_cdc_header_desc)) {
dev_dbg(&intf->dev, "CDC header len %u\n",
h->bLength);
goto err;
}
break;
case USB_CDC_UNION_TYPE:
if (found & 1 << USB_CDC_UNION_TYPE) {
dev_dbg(&intf->dev, "extra CDC union\n");
goto err;
}
if (h->bLength != sizeof(struct usb_cdc_union_desc)) {
dev_dbg(&intf->dev, "CDC union len %u\n",
h->bLength);
goto err;
}
cdc_union = (struct usb_cdc_union_desc *)buf;
break;
case USB_CDC_ETHERNET_TYPE:
if (found & 1 << USB_CDC_ETHERNET_TYPE) {
dev_dbg(&intf->dev, "extra CDC ether\n");
goto err;
}
if (h->bLength != sizeof(struct usb_cdc_ether_desc)) {
dev_dbg(&intf->dev, "CDC ether len %u\n",
h->bLength);
goto err;
}
cdc_ether = (struct usb_cdc_ether_desc *)buf;
break;
}
/* Remember which CDC functional descriptors we've seen. Works
* for all types we care about, of which USB_CDC_ETHERNET_TYPE
* (0x0f) is the highest numbered
*/
if (buf[2] < 32)
found |= 1 << buf[2];
next_desc:
len -= h->bLength;
buf += h->bLength;
}
/* Use separate control and data interfaces if we found a CDC Union */
if (cdc_union) {
info->data = usb_ifnum_to_if(dev->udev,
cdc_union->bSlaveInterface0);
if (desc->bInterfaceNumber != cdc_union->bMasterInterface0 ||
!info->data) {
dev_err(&intf->dev,
"bogus CDC Union: master=%u, slave=%u\n",
cdc_union->bMasterInterface0,
cdc_union->bSlaveInterface0);
goto err;
}
}
/* errors aren't fatal - we can live with the dynamic address */
if (cdc_ether) {
dev->hard_mtu = le16_to_cpu(cdc_ether->wMaxSegmentSize);
usbnet_get_ethernet_addr(dev, cdc_ether->iMACAddress);
}
/* claim data interface and set it up */
if (