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/* A wishbone slave testing module (a "mock") */
`default_nettype none
`include "messages.vh"
`ifndef SIMULATION
`error_SIMULATION_not_defined
; /* Cause syntax error */
`endif
module master_model
#(
parameter MASTER_NR = -1,
parameter OPERATIONS_FILE = "master_operations.mem",
parameter OPERATIONS_COUNT = 10
)
(
input wire ACK_I,
input wire CLK_I,
output wire [19:0] ADR_O,
input wire [15:0] DAT_I,
output wire [15:0] DAT_O,
input wire RST_I,
output wire STB_O,
output wire CYC_O,
output wire WE_O,
input wire STALL_I,
/* Non-wishbone */
output wire finished
);
parameter
OP_READ = 0,
OP_WRITE = 1,
OP_WAIT = 2, /* Keep CYC_O high, but STB_O low for 1 tick */
OP_DESELECT = 3; /* Drive CYC_O low for one tick */
/*
* Bits 39:36 specify type of the operation; bits 35:16 contain the
* address for read wnd write operations (may contain garbage otherwise);
* bits 15:0 contain data to write (for write operation) or expected data
* (for read operation) or are irrelevant (for other operations)
*/
reg [39:0] operations [OPERATIONS_COUNT - 1 : 0];
/*
* This will allow us to check whether read operation returned proper data;
* bit 16 tells us whether the corresponding command was a read; if not,
* bits 15:0 don't matter; if yes bits 15:0 contain the data we should
* receive from that read operation
*/
reg [16:0] expected_results [OPERATIONS_COUNT - 1 : 0];
integer i, j;
initial begin
$readmemh(OPERATIONS_FILE, operations, 0, OPERATIONS_COUNT - 1);
j = 0;
for (i = 0; i < OPERATIONS_COUNT; i++) begin
if (operations[i][39:36] == OP_READ ||
operations[i][39:36] == OP_WRITE) begin
if (operations[i][39:36] == OP_READ)
expected_results[j] <= {1'b1, operations[i][15:0]};
else
expected_results[j] <= {1'b0, 16'bx};
j++;
end
end
end
reg [31:0] operations_performed;
reg [31:0] commands_sent;
reg [31:0] commands_acknowledged;
/* Those are irrelevant if RST_I is high */
wire command_successful;
wire wait_successful;
wire deselect_successful;
wire [2:0] current_operation_type;
wire operation_successful;
wire [31:0] operations_performed_next_tick;
wire [39:0] operation_to_perform;
wire acknowledgement_successful;
wire [31:0] commands_sent_next_tick;
wire [31:0] commands_acknowledged_next_tick;
wire [31:0] acknowledgements_needed;
assign command_successful = CYC_O && STB_O && !STALL_I;
assign wait_successful = !STB_O && !STALL_I;
assign deselect_successful = !CYC_O;
assign current_operation_type = operations[operations_performed][39:36];
assign operation_successful
= operations_performed < OPERATIONS_COUNT &&
((current_operation_type == OP_READ && command_successful) ||
(current_operation_type == OP_WRITE && command_successful) ||
(current_operation_type == OP_WAIT && wait_successful) ||
(current_operation_type == OP_DESELECT && deselect_successful));
assign operations_performed_next_tick
= operations_performed + operation_successful;
assign operation_to_perform = operations[operations_performed_next_tick];
assign commands_sent_next_tick = commands_sent + command_successful;
assign acknowledgement_successful
= CYC_O && ACK_I && commands_sent_next_tick > commands_acknowledged;
assign commands_acknowledged_next_tick
= commands_acknowledged + acknowledgement_successful;
assign acknowledgements_needed
= commands_sent_next_tick - commands_acknowledged_next_tick;
reg strobe;
assign STB_O = strobe;
reg cycle;
assign CYC_O = cycle;
reg write_enable;
assign WE_O = write_enable;
reg [15:0] output_data;
assign DAT_O = output_data;
reg [19:0] addr;
assign ADR_O = addr;
reg done;
assign finished = done;
initial begin
strobe <= 0;
cycle <= 0;
operations_performed <= 0;
commands_sent <= 0;
commands_acknowledged <= 0;
done <= 0;
end
always @ (posedge CLK_I) begin
if (RST_I) begin
strobe <= 0;
cycle <= 0;
operations_performed <= 0;
commands_sent <= 0;
commands_acknowledged <= 0;
done <= 0;
end else begin
/* debug messages */
if (command_successful) begin
case (current_operation_type)
OP_READ : begin
`DBG(("Master %0d: sent read command at h%x", MASTER_NR,
operations[operations_performed][35:16]));
end
OP_WRITE : begin
`DBG(("Master %0d: sent write command of h%x at h%x",
MASTER_NR, operations[operations_performed][15:0],
operations[operations_performed][35:16]));
end
default :
`MSG(("Master %0d: error: bug in test bench", MASTER_NR));
endcase // case (current_operation_type)
end // if (command_successful)
if (acknowledgement_successful) begin
if (expected_results[commands_acknowledged][16])
`DBG(("Master %0d: acknowledged read of h%x", MASTER_NR, DAT_I));
else
`DBG(("Master %0d: acknowledged write", MASTER_NR));
end
operations_performed <= operations_performed_next_tick;
commands_sent <= commands_sent_next_tick;
commands_acknowledged <= commands_acknowledged_next_tick;
if (operations_performed_next_tick == OPERATIONS_COUNT) begin
strobe <= 0;
if (acknowledgements_needed == 0) begin
cycle <= 0;
done <= 1;
end
end else begin
operations_performed <= operations_performed_next_tick;
case (operation_to_perform[39:36])
OP_READ : begin
cycle <= 1;
strobe <= 1;
write_enable <= 0;
addr <= operation_to_perform[35:16];
end
OP_WRITE : begin
cycle <= 1;
strobe <= 1;
write_enable <= 1;
addr <= operation_to_perform[35:16];
output_data <= operation_to_perform[15:0];
end
OP_WAIT : begin
cycle <= 1;
strobe <= 0;
end
OP_DESELECT : begin
cycle <= acknowledgements_needed > 0;
strobe <= 0;
end
endcase // case (operation_to_perform[39:36])
end // else: !if(operations_performed_next_tick == OPERATIONS_COUNT)
if (acknowledgement_successful) begin
if (expected_results[commands_acknowledged][15:0] !== DAT_I &&
expected_results[commands_acknowledged][16]) begin
`MSG(("Master %0d: error: read h%x instead of h%x",
MASTER_NR, DAT_I,
expected_results[commands_acknowledged][15:0]));
end
end
end // else: !if(RST_I)
end // always @ (posedge CLK_I)
endmodule // master_model
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