From ecd7308793ad639880faf2a44f3b8b603d87c7fd Mon Sep 17 00:00:00 2001
From: Josh Blum <josh@joshknows.com>
Date: Fri, 9 Jul 2010 10:55:17 -0700
Subject: uhd: callback in vrt packet handler to handle overrun

---
 host/lib/transport/vrt_packet_handler.hpp | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

(limited to 'host/lib/transport')

diff --git a/host/lib/transport/vrt_packet_handler.hpp b/host/lib/transport/vrt_packet_handler.hpp
index f06fe94c0..11d749a81 100644
--- a/host/lib/transport/vrt_packet_handler.hpp
+++ b/host/lib/transport/vrt_packet_handler.hpp
@@ -21,6 +21,7 @@
 #include <uhd/config.hpp>
 #include <uhd/device.hpp>
 #include <uhd/utils/assert.hpp>
+#include <uhd/utils/byteswap.hpp>
 #include <uhd/types/io_type.hpp>
 #include <uhd/types/otw_type.hpp>
 #include <uhd/types/metadata.hpp>
@@ -39,6 +40,9 @@ namespace vrt_packet_handler{
  **********************************************************************/
     typedef std::vector<uhd::transport::managed_recv_buffer::sptr> managed_recv_buffs_t;
     typedef boost::function<bool(managed_recv_buffs_t &)> get_recv_buffs_t;
+    typedef boost::function<void(size_t /*which channel*/)> handle_overrun_t;
+
+    void handle_overrun_nop(size_t){}
 
     struct recv_state{
         //width of the receiver in channels
@@ -53,7 +57,7 @@ namespace vrt_packet_handler{
         size_t size_of_copy_buffs;
         size_t fragment_offset_in_samps;
 
-        recv_state(size_t width):
+        recv_state(size_t width = 1):
             width(width),
             next_packet_seq(width, 0),
             managed_buffs(width),
@@ -75,6 +79,7 @@ namespace vrt_packet_handler{
         uhd::rx_metadata_t &metadata,
         double tick_rate,
         vrt_unpacker_type vrt_unpacker,
+        const handle_overrun_t &handle_overrun,
         size_t vrt_header_offset_words32
     ){
         //vrt unpack each managed buffer
@@ -92,6 +97,7 @@ namespace vrt_packet_handler{
             const boost::uint32_t *vrt_hdr = state.managed_buffs[i]->cast<const boost::uint32_t *>() + vrt_header_offset_words32;
             if_packet_info.num_packet_words32 = num_packet_words32 - vrt_header_offset_words32;
             vrt_unpacker(vrt_hdr, if_packet_info);
+            const boost::uint32_t *vrt_data = vrt_hdr + if_packet_info.num_header_words32;
 
             //handle the packet count / sequence number
             if (if_packet_info.packet_count != state.next_packet_seq[i]){
@@ -102,12 +108,16 @@ namespace vrt_packet_handler{
             //make sure that its a data packet (TODO handle non-data packets)
             if (if_packet_info.packet_type != uhd::transport::vrt::if_packet_info_t::PACKET_TYPE_DATA){
                 std::cout << "vrt packet handler _recv1_helper got non data packet" << std::endl;
+                //extract the context word (we dont know the endianness so mirror the bytes)
+                boost::uint32_t word0 = vrt_data[0] | uhd::byteswap(vrt_data[0]);
+                if (word0 & 8) handle_overrun(i);
+                // 4: broken chain, 2: late command...
                 state.size_of_copy_buffs = 0;
                 return; //must exit here after setting the buffer
             }
 
             //setup the buffer to point to the data
-            state.copy_buffs[i] = reinterpret_cast<const boost::uint8_t *>(vrt_hdr + if_packet_info.num_header_words32);
+            state.copy_buffs[i] = reinterpret_cast<const boost::uint8_t *>(vrt_data);
 
             //store the minimum payload length into the copy buffer length
             size_t num_payload_bytes = if_packet_info.num_payload_words32*sizeof(boost::uint32_t);
@@ -142,7 +152,7 @@ namespace vrt_packet_handler{
         double tick_rate,
         vrt_unpacker_type vrt_unpacker,
         const get_recv_buffs_t &get_recv_buffs,
-        //use these two params to handle a layer above vrt
+        const handle_overrun_t &handle_overrun,
         size_t vrt_header_offset_words32
     ){
         metadata.has_time_spec = false; //false unless set in the helper
@@ -153,7 +163,9 @@ namespace vrt_packet_handler{
             if (not get_recv_buffs(state.managed_buffs)) return 0;
             try{
                 _recv1_helper(
-                    state, metadata, tick_rate, vrt_unpacker, vrt_header_offset_words32
+                    state, metadata, tick_rate,
+                    vrt_unpacker, handle_overrun,
+                    vrt_header_offset_words32
                 );
             }catch(const std::exception &e){
                 std::cerr << "Error (recv): " << e.what() << std::endl;
@@ -204,7 +216,7 @@ namespace vrt_packet_handler{
         double tick_rate,
         vrt_unpacker_type vrt_unpacker,
         const get_recv_buffs_t &get_recv_buffs,
-        //use these two params to handle a layer above vrt
+        const handle_overrun_t &handle_overrun = &handle_overrun_nop,
         size_t vrt_header_offset_words32 = 0
     ){
         switch(recv_mode){
@@ -221,6 +233,7 @@ namespace vrt_packet_handler{
                 tick_rate,
                 vrt_unpacker,
                 get_recv_buffs,
+                handle_overrun,
                 vrt_header_offset_words32
             );
         }
@@ -240,6 +253,7 @@ namespace vrt_packet_handler{
                     tick_rate,
                     vrt_unpacker,
                     get_recv_buffs,
+                    handle_overrun,
                     vrt_header_offset_words32
                 );
                 if (num_samps == 0) break; //had a recv timeout or error, break loop
@@ -328,7 +342,6 @@ namespace vrt_packet_handler{
         vrt_packer_type vrt_packer,
         const get_send_buffs_t &get_send_buffs,
         size_t max_samples_per_packet,
-        //use these two params to handle a layer above vrt
         size_t vrt_header_offset_words32 = 0
     ){
         //translate the metadata to vrt if packet info
-- 
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