The net common is too slow in usrp2 firmware to figure out if its vrt data.

Added a custom function to tell if a packet is vrt data, seems to be feeding fast enough at this rate...
Fixed some buffer size calculation logic.

3 files changed, 28 insertions, 12 deletions

diff --git a/firmware/microblaze/apps/txrx.c b/firmware/microblaze/apps/txrx.c
index e4e40e7e0..9c3caa4f2 100644
--- a/firmware/microblaze/apps/txrx.c
+++ b/firmware/microblaze/apps/txrx.c
@@ -158,19 +158,10 @@ static struct ip_addr get_my_ip_addr(void){
     return addr;
 }
 
-static bool _is_data;
-
 void handle_udp_data_packet(
     struct socket_address src, struct socket_address dst,
     unsigned char *payload, int payload_len
 ){
-    //forward this data to the dsp when the payload is sufficient
-    //the small payload is used to give the device the udp source port
-    if (payload_len > sizeof(uint32_t)){
-        _is_data = true;
-        return;
-    }
-
     //its a tiny payload, load the fast-path variables
     fp_mac_addr_src = get_my_eth_mac_addr();
     arp_cache_lookup_mac(&src.addr, &fp_mac_addr_dst);
@@ -513,9 +504,18 @@ void handle_udp_ctrl_packet(
 static bool
 eth_pkt_inspector(dbsm_t *sm, int bufno)
 {
-  _is_data = false;
-  handle_eth_packet(buffer_ram(bufno), buffer_pool_status->last_line[bufno] - 3);
-  return !_is_data;
+  //extract buffer point and length
+  uint32_t *buff = (uint32_t *)buffer_ram(bufno);
+  size_t len = buffer_pool_status->last_line[bufno] - 3;
+
+  //treat this as fast-path data?
+  if (is_udp_packet_with_vrt(buff, len, USRP2_UDP_DATA_PORT)){
+    return false;
+  }
+
+  //pass it to the slow-path handler
+  handle_eth_packet(buff, len);
+  return true;
 }
 
 //------------------------------------------------------------------
@@ -751,6 +751,10 @@ main(void)
   // tell app_common that this dbsm could be sending to the ethernet
   ac_could_be_sending_to_eth = &dsp_rx_sm;
 
+  sr_tx_ctrl->clear_state = 1;
+  bp_clear_buf(DSP_TX_BUF_0);
+  bp_clear_buf(DSP_TX_BUF_1);
+
   // kick off the state machine
   dbsm_start(&dsp_tx_sm);
 
diff --git a/firmware/microblaze/lib/net_common.c b/firmware/microblaze/lib/net_common.c
index 693502d18..ab7aadca9 100644
--- a/firmware/microblaze/lib/net_common.c
+++ b/firmware/microblaze/lib/net_common.c
@@ -378,6 +378,17 @@ handle_arp_packet(struct arp_eth_ipv4 *p, size_t size)
   }
 }
 
+bool is_udp_packet_with_vrt(uint32_t *p, size_t nlines, int port){
+    struct ip_hdr *ip = (struct ip_hdr *)(p + 4);
+    struct udp_hdr *udp = (struct udp_hdr *)(((char *)ip) + IP_HLEN);
+    uint32_t *payload = (uint32_t *)(((char *)udp) + UDP_HLEN);
+    return \
+        (p[3] & 0xffff) == ETHERTYPE_IPV4 &&
+        IPH_PROTO(ip) == IP_PROTO_UDP &&
+        udp->dest == port &&
+        payload[0] != 0; //must be non zero vrt header
+}
+
 void
 handle_eth_packet(uint32_t *p, size_t nlines)
 {
diff --git a/firmware/microblaze/lib/net_common.h b/firmware/microblaze/lib/net_common.h
index cfba43412..1a7052f71 100644
--- a/firmware/microblaze/lib/net_common.h
+++ b/firmware/microblaze/lib/net_common.h
@@ -56,5 +56,6 @@ void send_udp_pkt(int src_port, struct socket_address dst,
 
 void handle_eth_packet(uint32_t *p, size_t nlines);
 
+bool is_udp_packet_with_vrt(uint32_t *p, size_t nlines, int port);
 
 #endif /* INCLUDED_NET_COMMON_H */