Merge tag 'usb-3.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb

[karo-tx-linux.git] / drivers / net / usb / qmi_wwan.c

diff --git a/drivers/net/usb/qmi_wwan.c b/drivers/net/usb/qmi_wwan.c
index 968d5d50751dc120b406f54fffca49b46eafa230..5a88e72090ce7d0709d024a8c4b1f8fc173063a9 100644 (file)
--- a/drivers/net/usb/qmi_wwan.c
+++ b/drivers/net/usb/qmi_wwan.c
@@ -13,6 +13,7 @@
 #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>
@@ -52,6 +53,96 @@ struct qmi_wwan_state {
        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;
+
+       /* usbnet rx_complete guarantees that skb->len is at least
+        * hard_header_len, so we can inspect the dest address without
+        * checking skb->len
+        */
+       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)
 {
@@ -229,6 +320,18 @@ next_desc:
                usb_driver_release_interface(driver, info->data);
        }
 
+       /* Never use the same address on both ends of the link, even
+        * if the buggy firmware told us to.
+        */
+       if (!compare_ether_addr(dev->net->dev_addr, default_modem_addr))
+               eth_hw_addr_random(dev->net);
+
+       /* make MAC addr easily distinguishable from an IP header */
+       if (possibly_iphdr(dev->net->dev_addr)) {
+               dev->net->dev_addr[0] |= 0x02;  /* set local assignment bit */
+               dev->net->dev_addr[0] &= 0xbf;  /* clear "IP" bit */
+       }
+       dev->net->netdev_ops = &qmi_wwan_netdev_ops;
 err:
        return status;
 }
@@ -271,6 +374,11 @@ static int qmi_wwan_suspend(struct usb_interface *intf, pm_message_t message)
        struct qmi_wwan_state *info = (void *)&dev->data;
        int ret;
 
+       /*
+        * Both usbnet_suspend() and subdriver->suspend() MUST return 0
+        * in system sleep context, otherwise, the resume callback has
+        * to recover device from previous suspend failure.
+        */
        ret = usbnet_suspend(intf, message);
        if (ret < 0)
                goto err;
@@ -307,6 +415,7 @@ static const struct driver_info     qmi_wwan_info = {
        .bind           = qmi_wwan_bind,
        .unbind         = qmi_wwan_unbind,
        .manage_power   = qmi_wwan_manage_power,
+       .rx_fixup       = qmi_wwan_rx_fixup,
 };
 
 #define HUAWEI_VENDOR_ID       0x12D1