// 1/2 : route to proper - but this requires indicator in extcmd to distinguish i vs. d
// 2/1 : arbitrate
// 2/2 : passthru
//
// also handle special ops when possible (dcbz, ...)
// select one command per output bus
// ext_cmd is not tied to i/d, but does it need to have multiple outstanding (nop=0, and valid that require i/d info also must have that info provided)
// needs ext_tkn if not tied to i/d; needs to set q valid if tied to i/d (based on ext i or d type)
// seems like these are all tied to an i or d and require a response, so shouldn't need i+d+ext outstanding?
// possible extended command modifiers
// prefetch
// larx
// stcx
// lwsync
// hwsync
// tlbsync
// ici, icbi
// dci, dcbi, etc
// dcbtst
// dcbz
// tlbie, etc
// possible extended responses
// errors
// crit first, xfer# for larger bus width on core side
// credits
// resv valid
// stcx comp/pass
// sync ack
// back inv val/addr
// possible extra functions
// integrated L2
// doorbell/mailbox (peer/broadcast msg/rsp/intr side channel crossbar)
`include "defs.v"
reg [77:0] cmd_queue_q[0:1];
wire [77:0] cmd_queue_d[0:1];
wire [77:0] cmd_queue_in[0:1];
wire [77:0] cmd_queue_out;
reg [7:0] ext_queue_q;
wire [7:0] ext_queue_d;
wire [7:0] ext_queue_in;
module cmd_wb #(
parameter CORE_TYPE = `CORE_TYPE_WB2,
parameter BUS_TYPE = `BUS_TYPE_WB2
) (
input clk,
input rst,
input i_wb_cyc,
input i_wb_stb,
input [31:2] i_wb_adr,
input d_wb_cyc,
input d_wb_stb,
input d_wb_we,
input [3:0] d_wb_sel,
input [31:0] d_wb_adr,
input [31:0] d_wb_datw,
input [7:0] ext_cmd,
input [2:0] cmd_taken, // bit vector, one per queued cmd (could simultaneously occur in some designs)
output [77:0] cmd_out_0,
output [77:0] cmd_out_1
);
case (CORE_TYPE)
`CORE_TYPE_WB1: begin
// q[0] = i or d
assign cmd_queue_in[0][77] = d_wb_cyc & d_wb_stb; // valid - may need ext decode too
assign cmd_queue_in[0][76] = d_wb_we;
assign cmd_queue_in[0][75:72] = d_wb_sel;
assign cmd_queue_in[0][71:40] = d_wb_adr;
assign cmd_queue_in[0][39:8] = d_wb_datw;
assign cmd_queue_in[0][7:0] = ext_cmd;
end
`CORE_TYPE_WB2: begin
// q[0]=i, q[1]=d
assign cmd_queue_in[0][77] = i_wb_cyc & i_wb_stb; // valid - may need ext decode too
assign cmd_queue_in[0][76:72] = 'h0;
assign cmd_queue_in[0][71:40] = {i_wb_adr, 2'b0};
assign cmd_queue_in[0][39:8] = 'h0;
assign cmd_queue_in[0][7:0] = ext_cmd;
assign cmd_queue_in[1][77] = d_wb_cyc & d_wb_stb; // valid - may need ext decode too
assign cmd_queue_in[1][76] = d_wb_we;
assign cmd_queue_in[1][75:72] = d_wb_sel;
assign cmd_queue_in[1][71:40] = d_wb_adr;
assign cmd_queue_in[1][39:8] = d_wb_datw;
assign cmd_queue_in[1][7:0] = ext_cmd;
assign ext_queue_in = ext_cmd;
end
endcase
// queue routing/arbitration to cmd processing
// create generic command format out, handling i,d,ext!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
// dual wb cmds may need taken AND next; depends though on what should be ordering; start with INORDER=1 parameter?
case (CORE_TYPE)
`CORE_TYPE_WB1: begin
case (BUS_TYPE)
`BUS_TYPE_WB1: begin
assign cmd_out_0 = cmd_queue_q[0];
end
`BUS_TYPE_WB2: begin
assign cmd_out_0 = ext_queue_q[0] ? cmd_queue_q[1] : cmd_queue_q[7]; // select i vs d
end
endcase
end
`CORE_TYPE_WB2: begin
case (BUS_TYPE)
`BUS_TYPE_WB1:begin
// both valid: send d
// want selected bit; set first cycle; dont change once selected until not valid
wtf
3 years ago