usb: Add support for rndis uplink aggregation

RNDIS protocol supports data aggregation on uplink and can help
reduce mips by reducing number of interrupts on device. Throughput
also improved by 20-30%. Aggregation is disabled by setting
aggregation packet size to 1. To help better UL throughput, set
as ul aggregation support to 3 rndis packets by default. It can be
configured via module parameter: rndis_ul_max_pkt_per_xfer.

Change-Id: I0b62a21a5c3ceb6b04933d0d6da33301dbafe493
Signed-off-by: Vamsi Krishna <vskrishn@codeaurora.org>
Signed-off-by: Xerox Lin <xerox_lin@htc.com>
diff --git a/drivers/usb/gadget/function/rndis.c b/drivers/usb/gadget/function/rndis.c
index 31b3d550..fe9c044 100644
--- a/drivers/usb/gadget/function/rndis.c
+++ b/drivers/usb/gadget/function/rndis.c
@@ -42,6 +42,16 @@
 
 #include "rndis.h"
 
+int rndis_ul_max_pkt_per_xfer_rcvd;
+module_param(rndis_ul_max_pkt_per_xfer_rcvd, int, S_IRUGO);
+MODULE_PARM_DESC(rndis_ul_max_pkt_per_xfer_rcvd,
+		"Max num of REMOTE_NDIS_PACKET_MSGs received in a single transfer");
+
+int rndis_ul_max_xfer_size_rcvd;
+module_param(rndis_ul_max_xfer_size_rcvd, int, S_IRUGO);
+MODULE_PARM_DESC(rndis_ul_max_xfer_size_rcvd,
+		"Max size of bus transfer received");
+
 
 /* The driver for your USB chip needs to support ep0 OUT to work with
  * RNDIS, plus all three CDC Ethernet endpoints (interrupt not optional).
@@ -579,12 +589,12 @@
 	resp->MinorVersion = cpu_to_le32(RNDIS_MINOR_VERSION);
 	resp->DeviceFlags = cpu_to_le32(RNDIS_DF_CONNECTIONLESS);
 	resp->Medium = cpu_to_le32(RNDIS_MEDIUM_802_3);
-	resp->MaxPacketsPerTransfer = cpu_to_le32(1);
-	resp->MaxTransferSize = cpu_to_le32(
-		  params->dev->mtu
+	resp->MaxPacketsPerTransfer = cpu_to_le32(params->max_pkt_per_xfer);
+	resp->MaxTransferSize = cpu_to_le32(params->max_pkt_per_xfer *
+		(params->dev->mtu
 		+ sizeof(struct ethhdr)
 		+ sizeof(struct rndis_packet_msg_type)
-		+ 22);
+		+ 22));
 	resp->PacketAlignmentFactor = cpu_to_le32(0);
 	resp->AFListOffset = cpu_to_le32(0);
 	resp->AFListSize = cpu_to_le32(0);
@@ -964,6 +974,8 @@
 	params->dev = dev;
 	params->filter = cdc_filter;
 
+	rndis_ul_max_xfer_size_rcvd = 0;
+	rndis_ul_max_pkt_per_xfer_rcvd = 0;
 	return 0;
 }
 EXPORT_SYMBOL_GPL(rndis_set_param_dev);
@@ -996,6 +1008,13 @@
 }
 EXPORT_SYMBOL_GPL(rndis_set_param_medium);
 
+void rndis_set_max_pkt_xfer(u8 configNr, u8 max_pkt_per_xfer)
+{
+	pr_debug("%s:\n", __func__);
+
+	rndis_per_dev_params[configNr].max_pkt_per_xfer = max_pkt_per_xfer;
+}
+
 void rndis_add_hdr(struct sk_buff *skb)
 {
 	struct rndis_packet_msg_type *header;
@@ -1062,23 +1081,73 @@
 			struct sk_buff *skb,
 			struct sk_buff_head *list)
 {
-	/* tmp points to a struct rndis_packet_msg_type */
-	__le32 *tmp = (void *)skb->data;
+	int num_pkts = 1;
 
-	/* MessageType, MessageLength */
-	if (cpu_to_le32(RNDIS_MSG_PACKET)
-			!= get_unaligned(tmp++)) {
-		dev_kfree_skb_any(skb);
-		return -EINVAL;
-	}
-	tmp++;
+	if (skb->len > rndis_ul_max_xfer_size_rcvd)
+		rndis_ul_max_xfer_size_rcvd = skb->len;
 
-	/* DataOffset, DataLength */
-	if (!skb_pull(skb, get_unaligned_le32(tmp++) + 8)) {
-		dev_kfree_skb_any(skb);
-		return -EOVERFLOW;
+	while (skb->len) {
+		struct rndis_packet_msg_type *hdr;
+		struct sk_buff          *skb2;
+		u32             msg_len, data_offset, data_len;
+
+		/* some rndis hosts send extra byte to avoid zlp, ignore it */
+		if (skb->len == 1) {
+			dev_kfree_skb_any(skb);
+			return 0;
+		}
+
+		if (skb->len < sizeof *hdr) {
+			pr_err("invalid rndis pkt: skblen:%u hdr_len:%u",
+					skb->len, sizeof *hdr);
+			dev_kfree_skb_any(skb);
+			return -EINVAL;
+		}
+
+		hdr = (void *)skb->data;
+		msg_len = le32_to_cpu(hdr->MessageLength);
+		data_offset = le32_to_cpu(hdr->DataOffset);
+		data_len = le32_to_cpu(hdr->DataLength);
+
+		if (skb->len < msg_len ||
+				((data_offset + data_len + 8) > msg_len)) {
+			pr_err("invalid rndis message: %d/%d/%d/%d, len:%d\n",
+					le32_to_cpu(hdr->MessageType),
+					msg_len, data_offset, data_len, skb->len);
+			dev_kfree_skb_any(skb);
+			return -EOVERFLOW;
+		}
+		if (le32_to_cpu(hdr->MessageType) != RNDIS_MSG_PACKET) {
+			pr_err("invalid rndis message: %d/%d/%d/%d, len:%d\n",
+					le32_to_cpu(hdr->MessageType),
+					msg_len, data_offset, data_len, skb->len);
+			dev_kfree_skb_any(skb);
+			return -EINVAL;
+		}
+
+		skb_pull(skb, data_offset + 8);
+
+		if (msg_len == skb->len) {
+			skb_trim(skb, data_len);
+			break;
+		}
+
+		skb2 = skb_clone(skb, GFP_ATOMIC);
+		if (!skb2) {
+			pr_err("%s:skb clone failed\n", __func__);
+			dev_kfree_skb_any(skb);
+			return -ENOMEM;
+		}
+
+		skb_pull(skb, msg_len - sizeof *hdr);
+		skb_trim(skb2, data_len);
+		skb_queue_tail(list, skb2);
+
+		num_pkts++;
 	}
-	skb_trim(skb, get_unaligned_le32(tmp++));
+
+	if (num_pkts > rndis_ul_max_pkt_per_xfer_rcvd)
+		rndis_ul_max_pkt_per_xfer_rcvd = num_pkts;
 
 	skb_queue_tail(list, skb);
 	return 0;