1 files changed, 293 insertions, 352 deletions

diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c
index 74fab1a40156..d38bc20a60e2 100644
--- a/drivers/net/usb/cdc_ncm.c
+++ b/drivers/net/usb/cdc_ncm.c
@@ -51,90 +51,10 @@
 #include <linux/atomic.h>
 #include <linux/usb/usbnet.h>
 #include <linux/usb/cdc.h>
+#include <linux/usb/cdc_ncm.h>
 
 #define	DRIVER_VERSION				"14-Mar-2012"
 
-/* CDC NCM subclass 3.2.1 */
-#define USB_CDC_NCM_NDP16_LENGTH_MIN		0x10
-
-/* Maximum NTB length */
-#define	CDC_NCM_NTB_MAX_SIZE_TX			32768	/* bytes */
-#define	CDC_NCM_NTB_MAX_SIZE_RX			32768	/* bytes */
-
-/* Minimum value for MaxDatagramSize, ch. 6.2.9 */
-#define	CDC_NCM_MIN_DATAGRAM_SIZE		1514	/* bytes */
-
-#define	CDC_NCM_MIN_TX_PKT			512	/* bytes */
-
-/* Default value for MaxDatagramSize */
-#define	CDC_NCM_MAX_DATAGRAM_SIZE		8192	/* bytes */
-
-/*
- * Maximum amount of datagrams in NCM Datagram Pointer Table, not counting
- * the last NULL entry.
- */
-#define	CDC_NCM_DPT_DATAGRAMS_MAX		40
-
-/* Restart the timer, if amount of datagrams is less than given value */
-#define	CDC_NCM_RESTART_TIMER_DATAGRAM_CNT	3
-#define	CDC_NCM_TIMER_PENDING_CNT		2
-#define CDC_NCM_TIMER_INTERVAL			(400UL * NSEC_PER_USEC)
-
-/* The following macro defines the minimum header space */
-#define	CDC_NCM_MIN_HDR_SIZE \
-	(sizeof(struct usb_cdc_ncm_nth16) + sizeof(struct usb_cdc_ncm_ndp16) + \
-	(CDC_NCM_DPT_DATAGRAMS_MAX + 1) * sizeof(struct usb_cdc_ncm_dpe16))
-
-struct cdc_ncm_data {
-	struct usb_cdc_ncm_nth16 nth16;
-	struct usb_cdc_ncm_ndp16 ndp16;
-	struct usb_cdc_ncm_dpe16 dpe16[CDC_NCM_DPT_DATAGRAMS_MAX + 1];
-};
-
-struct cdc_ncm_ctx {
-	struct cdc_ncm_data tx_ncm;
-	struct usb_cdc_ncm_ntb_parameters ncm_parm;
-	struct hrtimer tx_timer;
-	struct tasklet_struct bh;
-
-	const struct usb_cdc_ncm_desc *func_desc;
-	const struct usb_cdc_header_desc *header_desc;
-	const struct usb_cdc_union_desc *union_desc;
-	const struct usb_cdc_ether_desc *ether_desc;
-
-	struct net_device *netdev;
-	struct usb_device *udev;
-	struct usb_host_endpoint *in_ep;
-	struct usb_host_endpoint *out_ep;
-	struct usb_host_endpoint *status_ep;
-	struct usb_interface *intf;
-	struct usb_interface *control;
-	struct usb_interface *data;
-
-	struct sk_buff *tx_curr_skb;
-	struct sk_buff *tx_rem_skb;
-
-	spinlock_t mtx;
-	atomic_t stop;
-
-	u32 tx_timer_pending;
-	u32 tx_curr_offset;
-	u32 tx_curr_last_offset;
-	u32 tx_curr_frame_num;
-	u32 rx_speed;
-	u32 tx_speed;
-	u32 rx_max;
-	u32 tx_max;
-	u32 max_datagram_size;
-	u16 tx_max_datagrams;
-	u16 tx_remainder;
-	u16 tx_modulus;
-	u16 tx_ndp_modulus;
-	u16 tx_seq;
-	u16 rx_seq;
-	u16 connected;
-};
-
 static void cdc_ncm_txpath_bh(unsigned long param);
 static void cdc_ncm_tx_timeout_start(struct cdc_ncm_ctx *ctx);
 static enum hrtimer_restart cdc_ncm_tx_timer_cb(struct hrtimer *hr_timer);
@@ -158,17 +78,19 @@ static u8 cdc_ncm_setup(struct cdc_ncm_ctx *ctx)
 	u8 flags;
 	u8 iface_no;
 	int err;
+	int eth_hlen;
 	u16 ntb_fmt_supported;
+	u32 min_dgram_size;
+	u32 min_hdr_size;
+	struct usbnet *dev = netdev_priv(ctx->netdev);
 
 	iface_no = ctx->control->cur_altsetting->desc.bInterfaceNumber;
 
-	err = usb_control_msg(ctx->udev,
-				usb_rcvctrlpipe(ctx->udev, 0),
-				USB_CDC_GET_NTB_PARAMETERS,
-				USB_TYPE_CLASS | USB_DIR_IN
-				 | USB_RECIP_INTERFACE,
-				0, iface_no, &ctx->ncm_parm,
-				sizeof(ctx->ncm_parm), 10000);
+	err = usbnet_read_cmd(dev, USB_CDC_GET_NTB_PARAMETERS,
+			      USB_TYPE_CLASS | USB_DIR_IN
+			      |USB_RECIP_INTERFACE,
+			      0, iface_no, &ctx->ncm_parm,
+			      sizeof(ctx->ncm_parm));
 	if (err < 0) {
 		pr_debug("failed GET_NTB_PARAMETERS\n");
 		return 1;
@@ -184,10 +106,19 @@ static u8 cdc_ncm_setup(struct cdc_ncm_ctx *ctx)
 	ctx->tx_max_datagrams = le16_to_cpu(ctx->ncm_parm.wNtbOutMaxDatagrams);
 	ntb_fmt_supported = le16_to_cpu(ctx->ncm_parm.bmNtbFormatsSupported);
 
-	if (ctx->func_desc != NULL)
+	eth_hlen = ETH_HLEN;
+	min_dgram_size = CDC_NCM_MIN_DATAGRAM_SIZE;
+	min_hdr_size = CDC_NCM_MIN_HDR_SIZE;
+	if (ctx->mbim_desc != NULL) {
+		flags = ctx->mbim_desc->bmNetworkCapabilities;
+		eth_hlen = 0;
+		min_dgram_size = CDC_MBIM_MIN_DATAGRAM_SIZE;
+		min_hdr_size = 0;
+	} else if (ctx->func_desc != NULL) {
 		flags = ctx->func_desc->bmNetworkCapabilities;
-	else
+	} else {
 		flags = 0;
+	}
 
 	pr_debug("dwNtbInMaxSize=%u dwNtbOutMaxSize=%u "
 		 "wNdpOutPayloadRemainder=%u wNdpOutDivisor=%u "
@@ -215,49 +146,19 @@ static u8 cdc_ncm_setup(struct cdc_ncm_ctx *ctx)
 
 	/* inform device about NTB input size changes */
 	if (ctx->rx_max != le32_to_cpu(ctx->ncm_parm.dwNtbInMaxSize)) {
+		__le32 dwNtbInMaxSize = cpu_to_le32(ctx->rx_max);
 
-		if (flags & USB_CDC_NCM_NCAP_NTB_INPUT_SIZE) {
-			struct usb_cdc_ncm_ndp_input_size *ndp_in_sz;
-
-			ndp_in_sz = kzalloc(sizeof(*ndp_in_sz), GFP_KERNEL);
-			if (!ndp_in_sz) {
-				err = -ENOMEM;
-				goto size_err;
-			}
-
-			err = usb_control_msg(ctx->udev,
-					usb_sndctrlpipe(ctx->udev, 0),
-					USB_CDC_SET_NTB_INPUT_SIZE,
-					USB_TYPE_CLASS | USB_DIR_OUT
-					 | USB_RECIP_INTERFACE,
-					0, iface_no, ndp_in_sz, 8, 1000);
-			kfree(ndp_in_sz);
-		} else {
-			__le32 *dwNtbInMaxSize;
-			dwNtbInMaxSize = kzalloc(sizeof(*dwNtbInMaxSize),
-					GFP_KERNEL);
-			if (!dwNtbInMaxSize) {
-				err = -ENOMEM;
-				goto size_err;
-			}
-			*dwNtbInMaxSize = cpu_to_le32(ctx->rx_max);
-
-			err = usb_control_msg(ctx->udev,
-					usb_sndctrlpipe(ctx->udev, 0),
-					USB_CDC_SET_NTB_INPUT_SIZE,
-					USB_TYPE_CLASS | USB_DIR_OUT
-					 | USB_RECIP_INTERFACE,
-					0, iface_no, dwNtbInMaxSize, 4, 1000);
-			kfree(dwNtbInMaxSize);
-		}
-size_err:
+		err = usbnet_write_cmd(dev, USB_CDC_SET_NTB_INPUT_SIZE,
+				       USB_TYPE_CLASS | USB_DIR_OUT
+				       | USB_RECIP_INTERFACE,
+				       0, iface_no, &dwNtbInMaxSize, 4);
 		if (err < 0)
 			pr_debug("Setting NTB Input Size failed\n");
 	}
 
 	/* verify maximum size of transmitted NTB in bytes */
 	if ((ctx->tx_max <
-	    (CDC_NCM_MIN_HDR_SIZE + CDC_NCM_MIN_DATAGRAM_SIZE)) ||
+	    (min_hdr_size + min_dgram_size)) ||
 	    (ctx->tx_max > CDC_NCM_NTB_MAX_SIZE_TX)) {
 		pr_debug("Using default maximum transmit length=%d\n",
 						CDC_NCM_NTB_MAX_SIZE_TX);
@@ -299,93 +200,85 @@ size_err:
 	}
 
 	/* adjust TX-remainder according to NCM specification. */
-	ctx->tx_remainder = ((ctx->tx_remainder - ETH_HLEN) &
-						(ctx->tx_modulus - 1));
+	ctx->tx_remainder = ((ctx->tx_remainder - eth_hlen) &
+			     (ctx->tx_modulus - 1));
 
 	/* additional configuration */
 
 	/* set CRC Mode */
 	if (flags & USB_CDC_NCM_NCAP_CRC_MODE) {
-		err = usb_control_msg(ctx->udev, usb_sndctrlpipe(ctx->udev, 0),
-				USB_CDC_SET_CRC_MODE,
-				USB_TYPE_CLASS | USB_DIR_OUT
-				 | USB_RECIP_INTERFACE,
-				USB_CDC_NCM_CRC_NOT_APPENDED,
-				iface_no, NULL, 0, 1000);
+		err = usbnet_write_cmd(dev, USB_CDC_SET_CRC_MODE,
+				       USB_TYPE_CLASS | USB_DIR_OUT
+				       | USB_RECIP_INTERFACE,
+				       USB_CDC_NCM_CRC_NOT_APPENDED,
+				       iface_no, NULL, 0);
 		if (err < 0)
 			pr_debug("Setting CRC mode off failed\n");
 	}
 
 	/* set NTB format, if both formats are supported */
 	if (ntb_fmt_supported & USB_CDC_NCM_NTH32_SIGN) {
-		err = usb_control_msg(ctx->udev, usb_sndctrlpipe(ctx->udev, 0),
-				USB_CDC_SET_NTB_FORMAT, USB_TYPE_CLASS
-				 | USB_DIR_OUT | USB_RECIP_INTERFACE,
-				USB_CDC_NCM_NTB16_FORMAT,
-				iface_no, NULL, 0, 1000);
+		err = usbnet_write_cmd(dev, USB_CDC_SET_NTB_FORMAT,
+				       USB_TYPE_CLASS | USB_DIR_OUT
+				       | USB_RECIP_INTERFACE,
+				       USB_CDC_NCM_NTB16_FORMAT,
+				       iface_no, NULL, 0);
 		if (err < 0)
 			pr_debug("Setting NTB format to 16-bit failed\n");
 	}
 
-	ctx->max_datagram_size = CDC_NCM_MIN_DATAGRAM_SIZE;
+	ctx->max_datagram_size = min_dgram_size;
 
 	/* set Max Datagram Size (MTU) */
 	if (flags & USB_CDC_NCM_NCAP_MAX_DATAGRAM_SIZE) {
-		__le16 *max_datagram_size;
-		u16 eth_max_sz = le16_to_cpu(ctx->ether_desc->wMaxSegmentSize);
-
-		max_datagram_size = kzalloc(sizeof(*max_datagram_size),
-				GFP_KERNEL);
-		if (!max_datagram_size) {
-			err = -ENOMEM;
+		__le16 max_datagram_size;
+		u16 eth_max_sz;
+		if (ctx->ether_desc != NULL)
+			eth_max_sz = le16_to_cpu(ctx->ether_desc->wMaxSegmentSize);
+		else if (ctx->mbim_desc != NULL)
+			eth_max_sz = le16_to_cpu(ctx->mbim_desc->wMaxSegmentSize);
+		else
 			goto max_dgram_err;
-		}
 
-		err = usb_control_msg(ctx->udev, usb_rcvctrlpipe(ctx->udev, 0),
-				USB_CDC_GET_MAX_DATAGRAM_SIZE,
-				USB_TYPE_CLASS | USB_DIR_IN
-				 | USB_RECIP_INTERFACE,
-				0, iface_no, max_datagram_size,
-				2, 1000);
+		err = usbnet_read_cmd(dev, USB_CDC_GET_MAX_DATAGRAM_SIZE,
+				      USB_TYPE_CLASS | USB_DIR_IN
+				      | USB_RECIP_INTERFACE,
+				      0, iface_no, &max_datagram_size, 2);
 		if (err < 0) {
 			pr_debug("GET_MAX_DATAGRAM_SIZE failed, use size=%u\n",
-						CDC_NCM_MIN_DATAGRAM_SIZE);
+				 min_dgram_size);
 		} else {
 			ctx->max_datagram_size =
-				le16_to_cpu(*max_datagram_size);
+				le16_to_cpu(max_datagram_size);
 			/* Check Eth descriptor value */
 			if (ctx->max_datagram_size > eth_max_sz)
 					ctx->max_datagram_size = eth_max_sz;
 
 			if (ctx->max_datagram_size > CDC_NCM_MAX_DATAGRAM_SIZE)
-				ctx->max_datagram_size =
-						CDC_NCM_MAX_DATAGRAM_SIZE;
+				ctx->max_datagram_size = CDC_NCM_MAX_DATAGRAM_SIZE;
 
-			if (ctx->max_datagram_size < CDC_NCM_MIN_DATAGRAM_SIZE)
-				ctx->max_datagram_size =
-					CDC_NCM_MIN_DATAGRAM_SIZE;
+			if (ctx->max_datagram_size < min_dgram_size)
+				ctx->max_datagram_size = min_dgram_size;
 
 			/* if value changed, update device */
 			if (ctx->max_datagram_size !=
-					le16_to_cpu(*max_datagram_size)) {
-				err = usb_control_msg(ctx->udev,
-						usb_sndctrlpipe(ctx->udev, 0),
+					le16_to_cpu(max_datagram_size)) {
+				err = usbnet_write_cmd(dev,
 						USB_CDC_SET_MAX_DATAGRAM_SIZE,
 						USB_TYPE_CLASS | USB_DIR_OUT
 						 | USB_RECIP_INTERFACE,
 						0,
-						iface_no, max_datagram_size,
-						2, 1000);
+						iface_no, &max_datagram_size,
+						2);
 				if (err < 0)
 					pr_debug("SET_MAX_DGRAM_SIZE failed\n");
 			}
 		}
-		kfree(max_datagram_size);
 	}
 
 max_dgram_err:
-	if (ctx->netdev->mtu != (ctx->max_datagram_size - ETH_HLEN))
-		ctx->netdev->mtu = ctx->max_datagram_size - ETH_HLEN;
+	if (ctx->netdev->mtu != (ctx->max_datagram_size - eth_hlen))
+		ctx->netdev->mtu = ctx->max_datagram_size - eth_hlen;
 
 	return 0;
 }
@@ -451,7 +344,7 @@ static const struct ethtool_ops cdc_ncm_ethtool_ops = {
 	.nway_reset = usbnet_nway_reset,
 };
 
-static int cdc_ncm_bind(struct usbnet *dev, struct usb_interface *intf)
+int cdc_ncm_bind_common(struct usbnet *dev, struct usb_interface *intf, u8 data_altsetting)
 {
 	struct cdc_ncm_ctx *ctx;
 	struct usb_driver *driver;
@@ -525,6 +418,13 @@ static int cdc_ncm_bind(struct usbnet *dev, struct usb_interface *intf)
 			ctx->func_desc = (const struct usb_cdc_ncm_desc *)buf;
 			break;
 
+		case USB_CDC_MBIM_TYPE:
+			if (buf[0] < sizeof(*(ctx->mbim_desc)))
+				break;
+
+			ctx->mbim_desc = (const struct usb_cdc_mbim_desc *)buf;
+			break;
+
 		default:
 			break;
 		}
@@ -537,7 +437,7 @@ advance:
 
 	/* check if we got everything */
 	if ((ctx->control == NULL) || (ctx->data == NULL) ||
-	    (ctx->ether_desc == NULL) || (ctx->control != intf))
+	    ((!ctx->mbim_desc) && ((ctx->ether_desc == NULL) || (ctx->control != intf))))
 		goto error;
 
 	/* claim data interface, if different from control */
@@ -559,7 +459,7 @@ advance:
 		goto error2;
 
 	/* configure data interface */
-	temp = usb_set_interface(dev->udev, iface_no, 1);
+	temp = usb_set_interface(dev->udev, iface_no, data_altsetting);
 	if (temp)
 		goto error2;
 
@@ -576,11 +476,13 @@ advance:
 	usb_set_intfdata(ctx->control, dev);
 	usb_set_intfdata(ctx->intf, dev);
 
-	temp = usbnet_get_ethernet_addr(dev, ctx->ether_desc->iMACAddress);
-	if (temp)
-		goto error2;
+	if (ctx->ether_desc) {
+		temp = usbnet_get_ethernet_addr(dev, ctx->ether_desc->iMACAddress);
+		if (temp)
+			goto error2;
+		dev_info(&dev->udev->dev, "MAC-Address: %pM\n", dev->net->dev_addr);
+	}
 
-	dev_info(&dev->udev->dev, "MAC-Address: %pM\n", dev->net->dev_addr);
 
 	dev->in = usb_rcvbulkpipe(dev->udev,
 		ctx->in_ep->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
@@ -589,13 +491,6 @@ advance:
 	dev->status = ctx->status_ep;
 	dev->rx_urb_size = ctx->rx_max;
 
-	/*
-	 * We should get an event when network connection is "connected" or
-	 * "disconnected". Set network connection in "disconnected" state
-	 * (carrier is OFF) during attach, so the IP network stack does not
-	 * start IPv6 negotiation and more.
-	 */
-	netif_carrier_off(dev->net);
 	ctx->tx_speed = ctx->rx_speed = 0;
 	return 0;
 
@@ -609,8 +504,9 @@ error:
 	dev_info(&dev->udev->dev, "bind() failure\n");
 	return -ENODEV;
 }
+EXPORT_SYMBOL_GPL(cdc_ncm_bind_common);
 
-static void cdc_ncm_unbind(struct usbnet *dev, struct usb_interface *intf)
+void cdc_ncm_unbind(struct usbnet *dev, struct usb_interface *intf)
 {
 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
 	struct usb_driver *driver = driver_of(intf);
@@ -644,52 +540,121 @@ static void cdc_ncm_unbind(struct usbnet *dev, struct usb_interface *intf)
 	usb_set_intfdata(ctx->intf, NULL);
 	cdc_ncm_free(ctx);
 }
+EXPORT_SYMBOL_GPL(cdc_ncm_unbind);
 
-static void cdc_ncm_zero_fill(u8 *ptr, u32 first, u32 end, u32 max)
+static int cdc_ncm_bind(struct usbnet *dev, struct usb_interface *intf)
 {
-	if (first >= max)
-		return;
-	if (first >= end)
-		return;
-	if (end > max)
-		end = max;
-	memset(ptr + first, 0, end - first);
+	int ret;
+
+	/* The MBIM spec defines a NCM compatible default altsetting,
+	 * which we may have matched:
+	 *
+	 *  "Functions that implement both NCM 1.0 and MBIM (an
+	 *   “NCM/MBIM function”) according to this recommendation
+	 *   shall provide two alternate settings for the
+	 *   Communication Interface.  Alternate setting 0, and the
+	 *   associated class and endpoint descriptors, shall be
+	 *   constructed according to the rules given for the
+	 *   Communication Interface in section 5 of [USBNCM10].
+	 *   Alternate setting 1, and the associated class and
+	 *   endpoint descriptors, shall be constructed according to
+	 *   the rules given in section 6 (USB Device Model) of this
+	 *   specification."
+	 *
+	 * Do not bind to such interfaces, allowing cdc_mbim to handle
+	 * them
+	 */
+#if IS_ENABLED(CONFIG_USB_NET_CDC_MBIM)
+	if ((intf->num_altsetting == 2) &&
+	    !usb_set_interface(dev->udev,
+			       intf->cur_altsetting->desc.bInterfaceNumber,
+			       CDC_NCM_COMM_ALTSETTING_MBIM) &&
+	    cdc_ncm_comm_intf_is_mbim(intf->cur_altsetting))
+		return -ENODEV;
+#endif
+
+	/* NCM data altsetting is always 1 */
+	ret = cdc_ncm_bind_common(dev, intf, 1);
+
+	/*
+	 * We should get an event when network connection is "connected" or
+	 * "disconnected". Set network connection in "disconnected" state
+	 * (carrier is OFF) during attach, so the IP network stack does not
+	 * start IPv6 negotiation and more.
+	 */
+	netif_carrier_off(dev->net);
+	return ret;
 }
 
-static struct sk_buff *
-cdc_ncm_fill_tx_frame(struct cdc_ncm_ctx *ctx, struct sk_buff *skb)
+static void cdc_ncm_align_tail(struct sk_buff *skb, size_t modulus, size_t remainder, size_t max)
 {
+	size_t align = ALIGN(skb->len, modulus) - skb->len + remainder;
+
+	if (skb->len + align > max)
+		align = max - skb->len;
+	if (align && skb_tailroom(skb) >= align)
+		memset(skb_put(skb, align), 0, align);
+}
+
+/* return a pointer to a valid struct usb_cdc_ncm_ndp16 of type sign, possibly
+ * allocating a new one within skb
+ */
+static struct usb_cdc_ncm_ndp16 *cdc_ncm_ndp(struct cdc_ncm_ctx *ctx, struct sk_buff *skb, __le32 sign, size_t reserve)
+{
+	struct usb_cdc_ncm_ndp16 *ndp16 = NULL;
+	struct usb_cdc_ncm_nth16 *nth16 = (void *)skb->data;
+	size_t ndpoffset = le16_to_cpu(nth16->wNdpIndex);
+
+	/* follow the chain of NDPs, looking for a match */
+	while (ndpoffset) {
+		ndp16 = (struct usb_cdc_ncm_ndp16 *)(skb->data + ndpoffset);
+		if  (ndp16->dwSignature == sign)
+			return ndp16;
+		ndpoffset = le16_to_cpu(ndp16->wNextNdpIndex);
+	}
+
+	/* align new NDP */
+	cdc_ncm_align_tail(skb, ctx->tx_ndp_modulus, 0, ctx->tx_max);
+
+	/* verify that there is room for the NDP and the datagram (reserve) */
+	if ((ctx->tx_max - skb->len - reserve) < CDC_NCM_NDP_SIZE)
+		return NULL;
+
+	/* link to it */
+	if (ndp16)
+		ndp16->wNextNdpIndex = cpu_to_le16(skb->len);
+	else
+		nth16->wNdpIndex = cpu_to_le16(skb->len);
+
+	/* push a new empty NDP */
+	ndp16 = (struct usb_cdc_ncm_ndp16 *)memset(skb_put(skb, CDC_NCM_NDP_SIZE), 0, CDC_NCM_NDP_SIZE);
+	ndp16->dwSignature = sign;
+	ndp16->wLength = cpu_to_le16(sizeof(struct usb_cdc_ncm_ndp16) + sizeof(struct usb_cdc_ncm_dpe16));
+	return ndp16;
+}
+
+struct sk_buff *
+cdc_ncm_fill_tx_frame(struct cdc_ncm_ctx *ctx, struct sk_buff *skb, __le32 sign)
+{
+	struct usb_cdc_ncm_nth16 *nth16;
+	struct usb_cdc_ncm_ndp16 *ndp16;
 	struct sk_buff *skb_out;
-	u32 rem;
-	u32 offset;
-	u32 last_offset;
-	u16 n = 0, index;
+	u16 n = 0, index, ndplen;
 	u8 ready2send = 0;
 
 	/* if there is a remaining skb, it gets priority */
-	if (skb != NULL)
+	if (skb != NULL) {
 		swap(skb, ctx->tx_rem_skb);
-	else
+		swap(sign, ctx->tx_rem_sign);
+	} else {
 		ready2send = 1;
-
-	/*
-	 * +----------------+
-	 * | skb_out        |
-	 * +----------------+
-	 *           ^ offset
-	 *        ^ last_offset
-	 */
+	}
 
 	/* check if we are resuming an OUT skb */
-	if (ctx->tx_curr_skb != NULL) {
-		/* pop variables */
-		skb_out = ctx->tx_curr_skb;
-		offset = ctx->tx_curr_offset;
-		last_offset = ctx->tx_curr_last_offset;
-		n = ctx->tx_curr_frame_num;
+	skb_out = ctx->tx_curr_skb;
 
-	} else {
-		/* reset variables */
+	/* allocate a new OUT skb */
+	if (!skb_out) {
 		skb_out = alloc_skb((ctx->tx_max + 1), GFP_ATOMIC);
 		if (skb_out == NULL) {
 			if (skb != NULL) {
@@ -698,35 +663,21 @@ cdc_ncm_fill_tx_frame(struct cdc_ncm_ctx *ctx, struct sk_buff *skb)
 			}
 			goto exit_no_skb;
 		}
+		/* fill out the initial 16-bit NTB header */
+		nth16 = (struct usb_cdc_ncm_nth16 *)memset(skb_put(skb_out, sizeof(struct usb_cdc_ncm_nth16)), 0, sizeof(struct usb_cdc_ncm_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++);
 
-		/* make room for NTH and NDP */
-		offset = ALIGN(sizeof(struct usb_cdc_ncm_nth16),
-					ctx->tx_ndp_modulus) +
-					sizeof(struct usb_cdc_ncm_ndp16) +
-					(ctx->tx_max_datagrams + 1) *
-					sizeof(struct usb_cdc_ncm_dpe16);
-
-		/* store last valid offset before alignment */
-		last_offset = offset;
-		/* align first Datagram offset correctly */
-		offset = ALIGN(offset, ctx->tx_modulus) + ctx->tx_remainder;
-		/* zero buffer till the first IP datagram */
-		cdc_ncm_zero_fill(skb_out->data, 0, offset, offset);
-		n = 0;
+		/* count total number of frames in this NTB */
 		ctx->tx_curr_frame_num = 0;
 	}
 
-	for (; n < ctx->tx_max_datagrams; n++) {
-		/* check if end of transmit buffer is reached */
-		if (offset >= ctx->tx_max) {
-			ready2send = 1;
-			break;
-		}
-		/* compute maximum buffer size */
-		rem = ctx->tx_max - offset;
-
+	for (n = ctx->tx_curr_frame_num; n < ctx->tx_max_datagrams; n++) {
+		/* send any remaining skb first */
 		if (skb == NULL) {
 			skb = ctx->tx_rem_skb;
+			sign = ctx->tx_rem_sign;
 			ctx->tx_rem_skb = NULL;
 
 			/* check for end of skb */
@@ -734,7 +685,14 @@ cdc_ncm_fill_tx_frame(struct cdc_ncm_ctx *ctx, struct sk_buff *skb)
 				break;
 		}
 
-		if (skb->len > rem) {
+		/* get the appropriate NDP for this skb */
+		ndp16 = cdc_ncm_ndp(ctx, skb_out, sign, skb->len + ctx->tx_modulus + ctx->tx_remainder);
+
+		/* align beginning of next frame */
+		cdc_ncm_align_tail(skb_out,  ctx->tx_modulus, ctx->tx_remainder, ctx->tx_max);
+
+		/* check if we had enough room left for both NDP and frame */
+		if (!ndp16 || skb_out->len + skb->len > ctx->tx_max) {
 			if (n == 0) {
 				/* won't fit, MTU problem? */
 				dev_kfree_skb_any(skb);
@@ -747,31 +705,30 @@ cdc_ncm_fill_tx_frame(struct cdc_ncm_ctx *ctx, struct sk_buff *skb)
 					ctx->netdev->stats.tx_dropped++;
 				}
 				ctx->tx_rem_skb = skb;
+				ctx->tx_rem_sign = sign;
 				skb = NULL;
 				ready2send = 1;
 			}
 			break;
 		}
 
-		memcpy(((u8 *)skb_out->data) + offset, skb->data, skb->len);
-
-		ctx->tx_ncm.dpe16[n].wDatagramLength = cpu_to_le16(skb->len);
-		ctx->tx_ncm.dpe16[n].wDatagramIndex = cpu_to_le16(offset);
-
-		/* update offset */
-		offset += skb->len;
-
-		/* store last valid offset before alignment */
-		last_offset = offset;
-
-		/* align offset correctly */
-		offset = ALIGN(offset, ctx->tx_modulus) + ctx->tx_remainder;
+		/* calculate frame number withing this NDP */
+		ndplen = le16_to_cpu(ndp16->wLength);
+		index = (ndplen - sizeof(struct usb_cdc_ncm_ndp16)) / sizeof(struct usb_cdc_ncm_dpe16) - 1;
 
-		/* zero padding */
-		cdc_ncm_zero_fill(skb_out->data, last_offset, offset,
-								ctx->tx_max);
+		/* OK, add this skb */
+		ndp16->dpe16[index].wDatagramLength = cpu_to_le16(skb->len);
+		ndp16->dpe16[index].wDatagramIndex = cpu_to_le16(skb_out->len);
+		ndp16->wLength = cpu_to_le16(ndplen + sizeof(struct usb_cdc_ncm_dpe16));
+		memcpy(skb_put(skb_out, skb->len), skb->data, skb->len);
 		dev_kfree_skb_any(skb);
 		skb = NULL;
+
+		/* send now if this NDP is full */
+		if (index >= CDC_NCM_DPT_DATAGRAMS_MAX) {
+			ready2send = 1;
+			break;
+		}
 	}
 
 	/* free up any dangling skb */
@@ -787,16 +744,12 @@ cdc_ncm_fill_tx_frame(struct cdc_ncm_ctx *ctx, struct sk_buff *skb)
 		/* wait for more frames */
 		/* push variables */
 		ctx->tx_curr_skb = skb_out;
-		ctx->tx_curr_offset = offset;
-		ctx->tx_curr_last_offset = last_offset;
 		goto exit_no_skb;
 
 	} else if ((n < ctx->tx_max_datagrams) && (ready2send == 0)) {
 		/* wait for more frames */
 		/* push variables */
 		ctx->tx_curr_skb = skb_out;
-		ctx->tx_curr_offset = offset;
-		ctx->tx_curr_last_offset = last_offset;
 		/* set the pending count */
 		if (n < CDC_NCM_RESTART_TIMER_DATAGRAM_CNT)
 			ctx->tx_timer_pending = CDC_NCM_TIMER_PENDING_CNT;
@@ -807,75 +760,24 @@ cdc_ncm_fill_tx_frame(struct cdc_ncm_ctx *ctx, struct sk_buff *skb)
 		/* variables will be reset at next call */
 	}
 
-	/* check for overflow */
-	if (last_offset > ctx->tx_max)
-		last_offset = ctx->tx_max;
-
-	/* revert offset */
-	offset = last_offset;
-
 	/*
 	 * If collected data size is less or equal CDC_NCM_MIN_TX_PKT bytes,
 	 * we send buffers as it is. If we get more data, it would be more
 	 * efficient for USB HS mobile device with DMA engine to receive a full
 	 * size NTB, than canceling DMA transfer and receiving a short packet.
 	 */
-	if (offset > CDC_NCM_MIN_TX_PKT)
-		offset = ctx->tx_max;
-
-	/* final zero padding */
-	cdc_ncm_zero_fill(skb_out->data, last_offset, offset, ctx->tx_max);
-
-	/* store last offset */
-	last_offset = offset;
-
-	if (((last_offset < ctx->tx_max) && ((last_offset %
-			le16_to_cpu(ctx->out_ep->desc.wMaxPacketSize)) == 0)) ||
-	    (((last_offset == ctx->tx_max) && ((ctx->tx_max %
-		le16_to_cpu(ctx->out_ep->desc.wMaxPacketSize)) == 0)) &&
-		(ctx->tx_max < le32_to_cpu(ctx->ncm_parm.dwNtbOutMaxSize)))) {
-		/* force short packet */
-		*(((u8 *)skb_out->data) + last_offset) = 0;
-		last_offset++;
-	}
-
-	/* zero the rest of the DPEs plus the last NULL entry */
-	for (; n <= CDC_NCM_DPT_DATAGRAMS_MAX; n++) {
-		ctx->tx_ncm.dpe16[n].wDatagramLength = 0;
-		ctx->tx_ncm.dpe16[n].wDatagramIndex = 0;
-	}
+	if (skb_out->len > CDC_NCM_MIN_TX_PKT)
+		/* final zero padding */
+		memset(skb_put(skb_out, ctx->tx_max - skb_out->len), 0, ctx->tx_max - skb_out->len);
 
-	/* fill out 16-bit NTB header */
-	ctx->tx_ncm.nth16.dwSignature = cpu_to_le32(USB_CDC_NCM_NTH16_SIGN);
-	ctx->tx_ncm.nth16.wHeaderLength =
-					cpu_to_le16(sizeof(ctx->tx_ncm.nth16));
-	ctx->tx_ncm.nth16.wSequence = cpu_to_le16(ctx->tx_seq);
-	ctx->tx_ncm.nth16.wBlockLength = cpu_to_le16(last_offset);
-	index = ALIGN(sizeof(struct usb_cdc_ncm_nth16), ctx->tx_ndp_modulus);
-	ctx->tx_ncm.nth16.wNdpIndex = cpu_to_le16(index);
-
-	memcpy(skb_out->data, &(ctx->tx_ncm.nth16), sizeof(ctx->tx_ncm.nth16));
-	ctx->tx_seq++;
-
-	/* fill out 16-bit NDP table */
-	ctx->tx_ncm.ndp16.dwSignature =
-				cpu_to_le32(USB_CDC_NCM_NDP16_NOCRC_SIGN);
-	rem = sizeof(ctx->tx_ncm.ndp16) + ((ctx->tx_curr_frame_num + 1) *
-					sizeof(struct usb_cdc_ncm_dpe16));
-	ctx->tx_ncm.ndp16.wLength = cpu_to_le16(rem);
-	ctx->tx_ncm.ndp16.wNextNdpIndex = 0; /* reserved */
-
-	memcpy(((u8 *)skb_out->data) + index,
-						&(ctx->tx_ncm.ndp16),
-						sizeof(ctx->tx_ncm.ndp16));
+	/* do we need to prevent a ZLP? */
+	if (((skb_out->len % le16_to_cpu(ctx->out_ep->desc.wMaxPacketSize)) == 0) &&
+	    (skb_out->len < le32_to_cpu(ctx->ncm_parm.dwNtbOutMaxSize)) && skb_tailroom(skb_out))
+		*skb_put(skb_out, 1) = 0;	/* force short packet */
 
-	memcpy(((u8 *)skb_out->data) + index + sizeof(ctx->tx_ncm.ndp16),
-					&(ctx->tx_ncm.dpe16),
-					(ctx->tx_curr_frame_num + 1) *
-					sizeof(struct usb_cdc_ncm_dpe16));
-
-	/* set frame length */
-	skb_put(skb_out, last_offset);
+	/* set final frame length */
+	nth16 = (struct usb_cdc_ncm_nth16 *)skb_out->data;
+	nth16->wBlockLength = cpu_to_le16(skb_out->len);
 
 	/* return skb */
 	ctx->tx_curr_skb = NULL;
@@ -888,6 +790,7 @@ exit_no_skb:
 		cdc_ncm_tx_timeout_start(ctx);
 	return NULL;
 }
+EXPORT_SYMBOL_GPL(cdc_ncm_fill_tx_frame);
 
 static void cdc_ncm_tx_timeout_start(struct cdc_ncm_ctx *ctx)
 {
@@ -922,6 +825,8 @@ static void cdc_ncm_txpath_bh(unsigned long param)
 		netif_tx_lock_bh(ctx->netdev);
 		usbnet_start_xmit(NULL, ctx->netdev);
 		netif_tx_unlock_bh(ctx->netdev);
+	} else {
+		spin_unlock_bh(&ctx->mtx);
 	}
 }
 
@@ -942,7 +847,7 @@ cdc_ncm_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
 		goto error;
 
 	spin_lock_bh(&ctx->mtx);
-	skb_out = cdc_ncm_fill_tx_frame(ctx, skb);
+	skb_out = cdc_ncm_fill_tx_frame(ctx, skb, cpu_to_le32(USB_CDC_NCM_NDP16_NOCRC_SIGN));
 	spin_unlock_bh(&ctx->mtx);
 	return skb_out;
 
@@ -953,17 +858,12 @@ error:
 	return NULL;
 }
 
-static int cdc_ncm_rx_fixup(struct usbnet *dev, struct sk_buff *skb_in)
+/* verify NTB header and return offset of first NDP, or negative error */
+int cdc_ncm_rx_verify_nth16(struct cdc_ncm_ctx *ctx, struct sk_buff *skb_in)
 {
-	struct sk_buff *skb;
-	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
-	int len;
-	int nframes;
-	int x;
-	int offset;
 	struct usb_cdc_ncm_nth16 *nth16;
-	struct usb_cdc_ncm_ndp16 *ndp16;
-	struct usb_cdc_ncm_dpe16 *dpe16;
+	int len;
+	int ret = -EINVAL;
 
 	if (ctx == NULL)
 		goto error;
@@ -997,20 +897,23 @@ static int cdc_ncm_rx_fixup(struct usbnet *dev, struct sk_buff *skb_in)
 	}
 	ctx->rx_seq = le16_to_cpu(nth16->wSequence);
 
-	len = le16_to_cpu(nth16->wNdpIndex);
-	if ((len + sizeof(struct usb_cdc_ncm_ndp16)) > skb_in->len) {
-		pr_debug("invalid DPT16 index <%u>\n",
-					le16_to_cpu(nth16->wNdpIndex));
-		goto error;
-	}
+	ret = le16_to_cpu(nth16->wNdpIndex);
+error:
+	return ret;
+}
+EXPORT_SYMBOL_GPL(cdc_ncm_rx_verify_nth16);
 
-	ndp16 = (struct usb_cdc_ncm_ndp16 *)(((u8 *)skb_in->data) + len);
+/* verify NDP header and return number of datagrams, or negative error */
+int cdc_ncm_rx_verify_ndp16(struct sk_buff *skb_in, int ndpoffset)
+{
+	struct usb_cdc_ncm_ndp16 *ndp16;
+	int ret = -EINVAL;
 
-	if (le32_to_cpu(ndp16->dwSignature) != USB_CDC_NCM_NDP16_NOCRC_SIGN) {
-		pr_debug("invalid DPT16 signature <%u>\n",
-					le32_to_cpu(ndp16->dwSignature));
+	if ((ndpoffset + sizeof(struct usb_cdc_ncm_ndp16)) > skb_in->len) {
+		pr_debug("invalid NDP offset  <%u>\n", ndpoffset);
 		goto error;
 	}
+	ndp16 = (struct usb_cdc_ncm_ndp16 *)(skb_in->data + ndpoffset);
 
 	if (le16_to_cpu(ndp16->wLength) < USB_CDC_NCM_NDP16_LENGTH_MIN) {
 		pr_debug("invalid DPT16 length <%u>\n",
@@ -1018,20 +921,52 @@ static int cdc_ncm_rx_fixup(struct usbnet *dev, struct sk_buff *skb_in)
 		goto error;
 	}
 
-	nframes = ((le16_to_cpu(ndp16->wLength) -
+	ret = ((le16_to_cpu(ndp16->wLength) -
 					sizeof(struct usb_cdc_ncm_ndp16)) /
 					sizeof(struct usb_cdc_ncm_dpe16));
-	nframes--; /* we process NDP entries except for the last one */
-
-	len += sizeof(struct usb_cdc_ncm_ndp16);
+	ret--; /* we process NDP entries except for the last one */
 
-	if ((len + nframes * (sizeof(struct usb_cdc_ncm_dpe16))) >
+	if ((sizeof(struct usb_cdc_ncm_ndp16) + ret * (sizeof(struct usb_cdc_ncm_dpe16))) >
 								skb_in->len) {
-		pr_debug("Invalid nframes = %d\n", nframes);
-		goto error;
+		pr_debug("Invalid nframes = %d\n", ret);
+		ret = -EINVAL;
 	}
 
-	dpe16 = (struct usb_cdc_ncm_dpe16 *)(((u8 *)skb_in->data) + len);
+error:
+	return ret;
+}
+EXPORT_SYMBOL_GPL(cdc_ncm_rx_verify_ndp16);
+
+static int cdc_ncm_rx_fixup(struct usbnet *dev, struct sk_buff *skb_in)
+{
+	struct sk_buff *skb;
+	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
+	int len;
+	int nframes;
+	int x;
+	int offset;
+	struct usb_cdc_ncm_ndp16 *ndp16;
+	struct usb_cdc_ncm_dpe16 *dpe16;
+	int ndpoffset;
+	int loopcount = 50; /* arbitrary max preventing infinite loop */
+
+	ndpoffset = cdc_ncm_rx_verify_nth16(ctx, skb_in);
+	if (ndpoffset < 0)
+		goto error;
+
+next_ndp:
+	nframes = cdc_ncm_rx_verify_ndp16(skb_in, ndpoffset);
+	if (nframes < 0)
+		goto error;
+
+	ndp16 = (struct usb_cdc_ncm_ndp16 *)(skb_in->data + ndpoffset);
+
+	if (le32_to_cpu(ndp16->dwSignature) != USB_CDC_NCM_NDP16_NOCRC_SIGN) {
+		pr_debug("invalid DPT16 signature <%u>\n",
+			 le32_to_cpu(ndp16->dwSignature));
+		goto err_ndp;
+	}
+	dpe16 = ndp16->dpe16;
 
 	for (x = 0; x < nframes; x++, dpe16++) {
 		offset = le16_to_cpu(dpe16->wDatagramIndex);
@@ -1043,7 +978,7 @@ static int cdc_ncm_rx_fixup(struct usbnet *dev, struct sk_buff *skb_in)
 		 */
 		if ((offset == 0) || (len == 0)) {
 			if (!x)
-				goto error; /* empty NTB */
+				goto err_ndp; /* empty NTB */
 			break;
 		}
 
@@ -1054,7 +989,7 @@ static int cdc_ncm_rx_fixup(struct usbnet *dev, struct sk_buff *skb_in)
 					"offset[%u]=%u, length=%u, skb=%p\n",
 					x, offset, len, skb_in);
 			if (!x)
-				goto error;
+				goto err_ndp;
 			break;
 
 		} else {
@@ -1067,6 +1002,12 @@ static int cdc_ncm_rx_fixup(struct usbnet *dev, struct sk_buff *skb_in)
 			usbnet_skb_return(dev, skb);
 		}
 	}
+err_ndp:
+	/* are there more NDPs to process? */
+	ndpoffset = le16_to_cpu(ndp16->wNextNdpIndex);
+	if (ndpoffset && loopcount--)
+		goto next_ndp;
+
 	return 1;
 error:
 	return 0;
@@ -1131,7 +1072,7 @@ static void cdc_ncm_status(struct usbnet *dev, struct urb *urb)
 		 * USB_CDC_NOTIFY_NETWORK_CONNECTION notification shall be
 		 * sent by device after USB_CDC_NOTIFY_SPEED_CHANGE.
 		 */
-		ctx->connected = event->wValue;
+		ctx->connected = le16_to_cpu(event->wValue);
 
 		printk(KERN_INFO KBUILD_MODNAME ": %s: network connection:"
 			" %sconnected\n",