RNDIS: Add Data aggregation (multi packet) support

Add data aggregation support using RNDIS Multi Packet feature
to achieve better UDP Downlink throughput. Max 3 RNDIS Packets
aggregated into one RNDIS Packet with this implementation.

With this change, seeing UDP Downlink throughput increase
from 90 Mbps to above 100 Mbps when using Iperf and sending
data more than 100 Mbps.

Change-Id: I21c39482718944bb1b1068bdd02f626531e58f08
Signed-off-by: Mayank Rana <mrana@codeaurora.org>
Signed-off-by: Rajkumar Raghupathy <raghup@codeaurora.org>

diff --git a/drivers/usb/gadget/function/f_rndis.c b/drivers/usb/gadget/function/f_rndis.c
index 479fa2938412493ff322db46589efc0081a6a82f..07fad13f93d2fac141ee953f4f029f77778d5944 100644 (file)
--- a/drivers/usb/gadget/function/f_rndis.c
+++ b/drivers/usb/gadget/function/f_rndis.c
@@ -460,6 +460,7 @@ static void rndis_command_complete(struct usb_ep *ep, struct usb_request *req)
 {
        struct f_rndis                  *rndis = req->context;
        int                             status;
+       rndis_init_msg_type             *buf;
 
        /* received RNDIS command from USB_CDC_SEND_ENCAPSULATED_COMMAND */
 //     spin_lock(&dev->lock);
@@ -467,6 +468,19 @@ static void rndis_command_complete(struct usb_ep *ep, struct usb_request *req)
        if (status < 0)
                pr_err("RNDIS command error %d, %d/%d\n",
                        status, req->actual, req->length);
+
+       buf = (rndis_init_msg_type *)req->buf;
+
+       if (buf->MessageType == RNDIS_MSG_INIT) {
+               if (buf->MaxTransferSize > 2048)
+                       rndis->port.multi_pkt_xfer = 1;
+               else
+                       rndis->port.multi_pkt_xfer = 0;
+               DBG(cdev, "%s: MaxTransferSize: %d : Multi_pkt_txr: %s\n",
+                               __func__, buf->MaxTransferSize,
+                               rndis->port.multi_pkt_xfer ? "enabled" :
+                                                           "disabled");
+       }
 //     spin_unlock(&dev->lock);
 }
 

diff --git a/drivers/usb/gadget/function/u_ether.c b/drivers/usb/gadget/function/u_ether.c
index 998e67b038647f48a29fd76d5f78b887250354f3..25a77ce82caa95af62eb921b2fb570d84ffdf677 100644 (file)
--- a/drivers/usb/gadget/function/u_ether.c
+++ b/drivers/usb/gadget/function/u_ether.c
@@ -67,6 +67,11 @@ struct eth_dev {
        spinlock_t              req_lock;       /* guard {rx,tx}_reqs */
        struct list_head        tx_reqs, rx_reqs;
        unsigned                tx_qlen;
+/* Minimum number of TX USB request queued to UDC */
+#define TX_REQ_THRESHOLD       5
+       int                     no_tx_req_used;
+       int                     tx_skb_hold_count;
+       u32                     tx_req_bufsize;
 
        struct sk_buff_head     rx_frames;
 
@@ -475,6 +480,11 @@ static void tx_complete(struct usb_ep *ep, struct usb_request *req)
 {
        struct sk_buff  *skb = req->context;
        struct eth_dev  *dev = ep->driver_data;
+       struct net_device *net = dev->net;
+       struct usb_request *new_req;
+       struct usb_ep *in;
+       int length;
+       int retval;
 
        switch (req->status) {
        default:
@@ -485,14 +495,73 @@ static void tx_complete(struct usb_ep *ep, struct usb_request *req)
        case -ESHUTDOWN:                /* disconnect etc */
                break;
        case 0:
-               dev->net->stats.tx_bytes += skb->len;
+               if (!req->zero)
+                       dev->net->stats.tx_bytes += req->length-1;
+               else
+                       dev->net->stats.tx_bytes += req->length;
        }
        dev->net->stats.tx_packets++;
 
        spin_lock(&dev->req_lock);
-       list_add(&req->list, &dev->tx_reqs);
-       spin_unlock(&dev->req_lock);
-       dev_kfree_skb_any(skb);
+       list_add_tail(&req->list, &dev->tx_reqs);
+
+       if (dev->port_usb->multi_pkt_xfer) {
+               dev->no_tx_req_used--;
+               req->length = 0;
+               in = dev->port_usb->in_ep;
+
+               if (!list_empty(&dev->tx_reqs)) {
+                       new_req = container_of(dev->tx_reqs.next,
+                                       struct usb_request, list);
+                       list_del(&new_req->list);
+                       spin_unlock(&dev->req_lock);
+                       if (new_req->length > 0) {
+                               length = new_req->length;
+
+                               /* NCM requires no zlp if transfer is
+                                * dwNtbInMaxSize */
+                               if (dev->port_usb->is_fixed &&
+                                       length == dev->port_usb->fixed_in_len &&
+                                       (length % in->maxpacket) == 0)
+                                       new_req->zero = 0;
+                               else
+                                       new_req->zero = 1;
+
+                               /* use zlp framing on tx for strict CDC-Ether
+                                * conformance, though any robust network rx
+                                * path ignores extra padding. and some hardware
+                                * doesn't like to write zlps.
+                                */
+                               if (new_req->zero && !dev->zlp &&
+                                               (length % in->maxpacket) == 0) {
+                                       new_req->zero = 0;
+                                       length++;
+                               }
+
+                               new_req->length = length;
+                               retval = usb_ep_queue(in, new_req, GFP_ATOMIC);
+                               switch (retval) {
+                               default:
+                                       DBG(dev, "tx queue err %d\n", retval);
+                                       break;
+                               case 0:
+                                       spin_lock(&dev->req_lock);
+                                       dev->no_tx_req_used++;
+                                       spin_unlock(&dev->req_lock);
+                                       net->trans_start = jiffies;
+                               }
+                       } else {
+                               spin_lock(&dev->req_lock);
+                               list_add(&new_req->list, &dev->tx_reqs);
+                               spin_unlock(&dev->req_lock);
+                       }
+               } else {
+                       spin_unlock(&dev->req_lock);
+               }
+       } else {
+               spin_unlock(&dev->req_lock);
+               dev_kfree_skb_any(skb);
+       }
 
        if (netif_carrier_ok(dev->net))
                netif_wake_queue(dev->net);
@@ -503,6 +572,26 @@ static inline int is_promisc(u16 cdc_filter)
        return cdc_filter & USB_CDC_PACKET_TYPE_PROMISCUOUS;
 }
 
+static void alloc_tx_buffer(struct eth_dev *dev)
+{
+       struct list_head        *act;
+       struct usb_request      *req;
+
+       dev->tx_req_bufsize = (TX_SKB_HOLD_THRESHOLD *
+                               (dev->net->mtu
+                               + sizeof(struct ethhdr)
+                               /* size of rndis_packet_msg_type */
+                               + 44
+                               + 22));
+
+       list_for_each(act, &dev->tx_reqs) {
+               req = container_of(act, struct usb_request, list);
+               if (!req->buf)
+                       req->buf = kmalloc(dev->tx_req_bufsize,
+                                               GFP_ATOMIC);
+       }
+}
+
 static netdev_tx_t eth_start_xmit(struct sk_buff *skb,
                                        struct net_device *net)
 {
@@ -529,6 +618,10 @@ static netdev_tx_t eth_start_xmit(struct sk_buff *skb,
                return NETDEV_TX_OK;
        }
 
+       /* Allocate memory for tx_reqs to support multi packet transfer */
+       if (dev->port_usb->multi_pkt_xfer && !dev->tx_req_bufsize)
+               alloc_tx_buffer(dev);
+
        /* apply outgoing CDC or RNDIS filters */
        if (skb && !is_promisc(cdc_filter)) {
                u8              *dest = skb->data;
@@ -591,9 +684,37 @@ static netdev_tx_t eth_start_xmit(struct sk_buff *skb,
                }
        }
 
-       length = skb->len;
-       req->buf = skb->data;
-       req->context = skb;
+       spin_lock_irqsave(&dev->req_lock, flags);
+       dev->tx_skb_hold_count++;
+       spin_unlock_irqrestore(&dev->req_lock, flags);
+
+       if (dev->port_usb->multi_pkt_xfer) {
+               memcpy(req->buf + req->length, skb->data, skb->len);
+               req->length = req->length + skb->len;
+               length = req->length;
+               dev_kfree_skb_any(skb);
+
+               spin_lock_irqsave(&dev->req_lock, flags);
+               if (dev->tx_skb_hold_count < TX_SKB_HOLD_THRESHOLD) {
+                       if (dev->no_tx_req_used > TX_REQ_THRESHOLD) {
+                               list_add(&req->list, &dev->tx_reqs);
+                               spin_unlock_irqrestore(&dev->req_lock, flags);
+                               goto success;
+                       }
+               }
+
+               dev->no_tx_req_used++;
+               spin_unlock_irqrestore(&dev->req_lock, flags);
+
+               spin_lock_irqsave(&dev->lock, flags);
+               dev->tx_skb_hold_count = 0;
+               spin_unlock_irqrestore(&dev->lock, flags);
+       } else {
+               length = skb->len;
+               req->buf = skb->data;
+               req->context = skb;
+       }
+
        req->complete = tx_complete;
 
        /* NCM requires no zlp if transfer is dwNtbInMaxSize */
@@ -608,8 +729,10 @@ static netdev_tx_t eth_start_xmit(struct sk_buff *skb,
         * though any robust network rx path ignores extra padding.
         * and some hardware doesn't like to write zlps.
         */
-       if (req->zero && !dev->zlp && (length % in->maxpacket) == 0)
+       if (req->zero && !dev->zlp && (length % in->maxpacket) == 0) {
+               req->zero = 0;
                length++;
+       }
 
        req->length = length;
 
@@ -617,7 +740,7 @@ static netdev_tx_t eth_start_xmit(struct sk_buff *skb,
        if (gadget_is_dualspeed(dev->gadget) &&
                         (dev->gadget->speed == USB_SPEED_HIGH)) {
                dev->tx_qlen++;
-               if (dev->tx_qlen == qmult) {
+               if (dev->tx_qlen == (qmult/2)) {
                        req->no_interrupt = 0;
                        dev->tx_qlen = 0;
                } else {
@@ -637,7 +760,8 @@ static netdev_tx_t eth_start_xmit(struct sk_buff *skb,
        }
 
        if (retval) {
-               dev_kfree_skb_any(skb);
+               if (!dev->port_usb->multi_pkt_xfer)
+                       dev_kfree_skb_any(skb);
 drop:
                dev->net->stats.tx_dropped++;
 multiframe:
@@ -647,6 +771,7 @@ multiframe:
                list_add(&req->list, &dev->tx_reqs);
                spin_unlock_irqrestore(&dev->req_lock, flags);
        }
+success:
        return NETDEV_TX_OK;
 }
 
@@ -1121,6 +1246,9 @@ struct net_device *gether_connect(struct gether *link)
                dev->ul_max_pkts_per_xfer = link->ul_max_pkts_per_xfer;
 
                spin_lock(&dev->lock);
+               dev->tx_skb_hold_count = 0;
+               dev->no_tx_req_used = 0;
+               dev->tx_req_bufsize = 0;
                dev->port_usb = link;
                if (netif_running(dev->net)) {
                        if (link->open)
@@ -1188,6 +1316,8 @@ void gether_disconnect(struct gether *link)
                list_del(&req->list);
 
                spin_unlock(&dev->req_lock);
+               if (link->multi_pkt_xfer)
+                       kfree(req->buf);
                usb_ep_free_request(link->in_ep, req);
                spin_lock(&dev->req_lock);
        }