diff options
| -rw-r--r-- | usrp2/fifo/ll8_to_fifo19.v | 71 |
1 files changed, 44 insertions, 27 deletions
diff --git a/usrp2/fifo/ll8_to_fifo19.v b/usrp2/fifo/ll8_to_fifo19.v index af3b91afb..3c95c2374 100644 --- a/usrp2/fifo/ll8_to_fifo19.v +++ b/usrp2/fifo/ll8_to_fifo19.v @@ -10,33 +10,42 @@ module ll8_to_fifo19 output [18:0] f19_data, output f19_src_rdy_o, input f19_dst_rdy_i ); + + // Short FIFO on input to guarantee no deadlock + wire [7:0] ll_data_int; + wire ll_sof_int, ll_eof_int, ll_src_rdy_int, ll_dst_rdy_int; + wire ll_dst_rdy; + + ll8_shortfifo head_fifo + (.clk(clk), .reset(reset), .clear(clear), + .datain(ll_data), .sof_i(~ll_sof_n), .eof_i(~ll_eof_n), + .error_i(0), .src_rdy_i(~ll_src_rdy_n), .dst_rdy_o(ll_dst_rdy), + .dataout(ll_data_int), .sof_o(ll_sof_int), .eof_o(ll_eof_int), + .error_o(), .src_rdy_o(ll_src_rdy_int), .dst_rdy_i(ll_dst_rdy_int)); + + assign ll_dst_rdy_n = ~ll_dst_rdy; + // Actual ll8_to_fifo19 which could deadlock if not connected to a shortfifo localparam XFER_EMPTY = 0; localparam XFER_HALF = 1; localparam XFER_HALF_WRITE = 3; - // Why anybody would use active low in an FPGA is beyond me... - wire ll_sof = ~ll_sof_n; - wire ll_eof = ~ll_eof_n; - wire ll_src_rdy = ~ll_src_rdy_n; - wire ll_dst_rdy; - assign ll_dst_rdy_n = ~ll_dst_rdy; - - wire xfer_out = f19_src_rdy_o & f19_dst_rdy_i; - wire xfer_in = ll_src_rdy & ll_dst_rdy; - - reg hold_sof; - wire f19_sof, f19_eof, f19_occ; + wire [18:0] f19_data_int; + wire f19_sof_int, f19_eof_int, f19_occ_int, f19_src_rdy_int, f19_dst_rdy_int; + + wire xfer_out = f19_src_rdy_int & f19_dst_rdy_int; + wire xfer_in = ll_src_rdy_int & ll_dst_rdy_int; + reg hold_sof; - reg [1:0] state; - reg [7:0] hold_reg; + reg [1:0] state; + reg [7:0] hold_reg; always @(posedge clk) - if(ll_src_rdy & (state==XFER_EMPTY)) - hold_reg <= ll_data; + if(ll_src_rdy_int & (state==XFER_EMPTY)) + hold_reg <= ll_data_int; always @(posedge clk) - if(ll_sof & (state==XFER_EMPTY)) + if(ll_sof_int & (state==XFER_EMPTY)) hold_sof <= 1; else if(xfer_out) hold_sof <= 0; @@ -47,27 +56,35 @@ module ll8_to_fifo19 else case(state) XFER_EMPTY : - if(ll_src_rdy) - if(ll_eof) + if(ll_src_rdy_int) + if(ll_eof_int) state <= XFER_HALF_WRITE; else state <= XFER_HALF; XFER_HALF : - if(ll_src_rdy & f19_dst_rdy_i) + if(ll_src_rdy_int & f19_dst_rdy_int) state <= XFER_EMPTY; XFER_HALF_WRITE : - if(f19_dst_rdy_i) + if(f19_dst_rdy_int) state <= XFER_EMPTY; endcase // case (state) - assign ll_dst_rdy = (state==XFER_EMPTY) | ((state==XFER_HALF)&f19_dst_rdy_i); - assign f19_src_rdy_o = (state==XFER_HALF_WRITE) | ((state==XFER_HALF)&ll_src_rdy); + assign ll_dst_rdy_int = (state==XFER_EMPTY) | ((state==XFER_HALF)&f19_dst_rdy_int); + assign f19_src_rdy_int= (state==XFER_HALF_WRITE) | ((state==XFER_HALF)&ll_src_rdy_int); - assign f19_sof = hold_sof | (ll_sof & (state==XFER_HALF)); - assign f19_eof = (state == XFER_HALF_WRITE) | ll_eof; - assign f19_occ = (state == XFER_HALF_WRITE); + assign f19_sof_int = hold_sof | (ll_sof_int & (state==XFER_HALF)); + assign f19_eof_int = (state == XFER_HALF_WRITE) | ll_eof_int; + assign f19_occ_int = (state == XFER_HALF_WRITE); - assign f19_data = {f19_occ,f19_eof,f19_sof,hold_reg,ll_data}; + assign f19_data_int = {f19_occ_int,f19_eof_int,f19_sof_int,hold_reg,ll_data_int}; + + // Shortfifo on output to guarantee no deadlock + fifo_short #(.WIDTH(19)) tail_fifo + (.clk(clk),.reset(reset),.clear(clear), + .datain(f19_data_int), .src_rdy_i(f19_src_rdy_int), .dst_rdy_o(f19_dst_rdy_int), + .dataout(f19_data), .src_rdy_o(f19_src_rdy_o), .dst_rdy_i(f19_dst_rdy_i), + .space(),.occupied() ); + endmodule // ll8_to_fifo19 |