diff options
Diffstat (limited to 'fpga/usrp3/lib/packet_proc/source_flow_control.v')
| -rw-r--r-- | fpga/usrp3/lib/packet_proc/source_flow_control.v | 127 |
1 files changed, 0 insertions, 127 deletions
diff --git a/fpga/usrp3/lib/packet_proc/source_flow_control.v b/fpga/usrp3/lib/packet_proc/source_flow_control.v deleted file mode 100644 index d26b848c9..000000000 --- a/fpga/usrp3/lib/packet_proc/source_flow_control.v +++ /dev/null @@ -1,127 +0,0 @@ - -// source_flow_control.v -// -// This block passes the in_* AXI port to the out_* AXI port only when it has -// enough flow control credits. Data is held when there are not enough credits. -// Credits are replenished with extension context packets which update the -// last_consumed packet register. Max credits are controlled by settings regs. -// The 2nd line of the packet contains the sequence number in the low 12 bits. -// These packets should not have a time value, but if they do it will be ignored. - -module source_flow_control - #(parameter BASE=0) - (input clk, input reset, input clear, - input set_stb, input [7:0] set_addr, input [31:0] set_data, - input [63:0] fc_tdata, input fc_tlast, input fc_tvalid, output fc_tready, - input [63:0] in_tdata, input in_tlast, input in_tvalid, output in_tready, - output [63:0] out_tdata, output out_tlast, output out_tvalid, input out_tready); - - reg [31:0] last_seqnum_consumed; - wire [31:0] window_size; - wire [31:0] go_until_seqnum = last_seqnum_consumed + window_size + 1; - reg [31:0] current_seqnum; - wire window_reset; - wire window_enable; - wire setting_changed; - - setting_reg #(.my_addr(BASE)) sr_window_size - (.clk(clk),.rst(reset),.strobe(set_stb),.addr(set_addr),.in(set_data), - .out(window_size),.changed(setting_changed)); - - setting_reg #(.my_addr(BASE+1), .width(1)) sr_window_enable - (.clk(clk),.rst(reset),.strobe(set_stb),.addr(set_addr),.in(set_data), - .out(window_enable),.changed(window_reset)); - - reg go; - reg [1:0] sfc_state; - - - localparam SFC_HEAD = 2'd0; - localparam SFC_TIME = 2'd1; - localparam SFC_BODY = 2'd2; - localparam SFC_DUMP = 2'd3; - - always @(posedge clk) - if(reset | clear | window_reset) - begin - last_seqnum_consumed <= 32'hFFFFFFFF; - sfc_state <= SFC_HEAD; - end - else - if(fc_tvalid & fc_tready) - case(sfc_state) - SFC_HEAD : - if(fc_tlast) - sfc_state <= SFC_HEAD; // Error. CHDR packet with only a header is an error. - else if(~fc_tdata[63]) // Is this NOT an extension context packet? - sfc_state <= SFC_DUMP; // Error. Only extension context packets should come in on this interface. - else if(fc_tdata[61]) // Does this packet have time? - sfc_state <= SFC_TIME; - else - sfc_state <= SFC_BODY; - - SFC_TIME : - if(fc_tlast) - sfc_state <= SFC_HEAD; // Error, CHDR packet with only header and time is an error. - else - sfc_state <= SFC_BODY; - - SFC_BODY : - begin - last_seqnum_consumed <= fc_tdata[31:0]; // Sequence number is in lower 32bits. - if(fc_tlast) - sfc_state <= SFC_HEAD; - else - sfc_state <= SFC_DUMP; // Error. Not expecting any more data in a CHDR packet. - end - - SFC_DUMP : // shouldn't ever need to be here, this is an error condition - if(fc_tlast) - sfc_state <= SFC_HEAD; - endcase // case (sfc_state) - - assign fc_tready = 1'b1; // Always consume FC -- FIXME Even if we are getting reset? - assign out_tdata = in_tdata; // CHDR data flows through combinatorially. - assign out_tlast = in_tlast; - assign in_tready = go ? out_tready : 1'b0; - assign out_tvalid = go ? in_tvalid : 1'b0; - - // - // Each time we recieve the end of an IF data packet increment the current_seqnum. - // We bravely assume that no packets go missing...or at least that they will be detected elsewhere - // and then handled appropriately. - // The SEQNUM needs to be initialized every time we start a new stream. In new_rx_framer this is done - // as a side effect of writing a new SID value to the setting reg. - // - // By incrementing current_seqnum on the last signal we get the nice effect that packet flow is - // always suspended between packets rather than within a packet. - // - always @(posedge clk) - if(reset | clear | window_reset) - current_seqnum <= 0; - else if (in_tvalid && in_tready && in_tlast) - current_seqnum <= current_seqnum + 1; - - always @(posedge clk) - if(reset | clear) - go <= 1'b0; - else - if(~window_enable) - go <= 1'b1; - else - case(go) - 1'b0 : - // This test assumes the host is well behaved in sending good numbers for packets consumed - // and that current_seqnum increments always by 1 only. - // This way wraps are dealt with without a large logic penalty. - if (in_tvalid & (go_until_seqnum - current_seqnum != 0)) - // if(in_tvalid & (go_until_seqnum > current_seqnum)) // FIXME will need to handle wrap of 32-bit seqnum - go <= 1'b1; - - 1'b1 : - if(in_tvalid & in_tready & in_tlast) - go <= 1'b0; - endcase // case (go) - - -endmodule // source_flow_control |