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Diffstat (limited to 'fpga/usrp2/gpif/packet_splitter.v')
| -rw-r--r-- | fpga/usrp2/gpif/packet_splitter.v | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/fpga/usrp2/gpif/packet_splitter.v b/fpga/usrp2/gpif/packet_splitter.v new file mode 100644 index 000000000..ba4c8cded --- /dev/null +++ b/fpga/usrp2/gpif/packet_splitter.v @@ -0,0 +1,123 @@ +// +// Copyright 2011 Ettus Research LLC +// +// This program is free software: you can redistribute it and/or modify +// it under the terms of the GNU General Public License as published by +// the Free Software Foundation, either version 3 of the License, or +// (at your option) any later version. +// +// This program is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License +// along with this program. If not, see <http://www.gnu.org/licenses/>. +// + + +// Split vita packets longer than one GPIF frame, add padding on short frames + +module packet_splitter + #(parameter FRAME_LEN=256) + (input clk, input reset, input clear, + input [7:0] frames_per_packet, + input [18:0] data_i, + input src_rdy_i, + output dst_rdy_o, + output [18:0] data_o, + output src_rdy_o, + input dst_rdy_i, + output [31:0] debug0, + output [31:0] debug1); + + reg [1:0] state; + reg [15:0] length; + reg [15:0] frame_len; + reg [7:0] frame_count; + + localparam PS_IDLE = 0; + localparam PS_FRAME = 1; + localparam PS_NEW_FRAME = 2; + localparam PS_PAD = 3; + + wire eof_i = data_i[17]; + + always @(posedge clk) + if(reset | clear) + begin + state <= PS_IDLE; + frame_count <= 0; + end + else + case(state) + PS_IDLE : + if(src_rdy_i & dst_rdy_i) + begin + length <= { data_i[14:0],1'b0}; + frame_len <= FRAME_LEN; + state <= PS_FRAME; + frame_count <= 1; + end + PS_FRAME : + if(src_rdy_i & dst_rdy_i) + if((frame_len == 2) & ((length == 2) | eof_i)) + state <= PS_IDLE; + else if(frame_len == 2) + begin + length <= length - 1; + state <= PS_NEW_FRAME; + frame_count <= frame_count + 1; + end + else if((length == 2)|eof_i) + begin + frame_len <= frame_len - 1; + state <= PS_PAD; + end + else + begin + frame_len <= frame_len - 1; + length <= length - 1; + end + PS_NEW_FRAME : + if(src_rdy_i & dst_rdy_i) + begin + frame_len <= FRAME_LEN; + if((length == 2)|eof_i) + state <= PS_PAD; + else + begin + state <= PS_FRAME; + length <= length - 1; + end // else: !if((length == 2)|eof_i) + end // if (src_rdy_i & dst_rdy_i) + + PS_PAD : + if(dst_rdy_i) + if(frame_len == 2) + state <= PS_IDLE; + else + frame_len <= frame_len - 1; + + endcase // case (state) + + wire next_state_is_idle = dst_rdy_i & (frame_len==2) & + ( (state==PS_PAD) | ( (state==PS_FRAME) & src_rdy_i & ((length==2)|eof_i) ) ); + + + + + assign dst_rdy_o = dst_rdy_i & (state != PS_PAD); + assign src_rdy_o = src_rdy_i | (state == PS_PAD); + + wire eof_out = (frame_len == 2) & (state != PS_IDLE) & (state != PS_NEW_FRAME); + wire sof_out = (state == PS_IDLE) | (state == PS_NEW_FRAME); + wire occ_out = eof_out & next_state_is_idle & (frames_per_packet != frame_count); + + wire [15:0] data_out = data_i[15:0]; + assign data_o = {occ_out, eof_out, sof_out, data_out}; + + assign debug0 = { 8'd0, dst_rdy_o, src_rdy_o, next_state_is_idle, eof_out, sof_out, occ_out, state[1:0], frame_count[7:0], frames_per_packet[7:0] }; + assign debug1 = { length[15:0], frame_len[15:0] }; + +endmodule // packet_splitter |