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litex/verilog/lm32/lm32_jtag.v

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// ==================================================================
// >>>>>>>>>>>>>>>>>>>>>>> COPYRIGHT NOTICE <<<<<<<<<<<<<<<<<<<<<<<<<
// ------------------------------------------------------------------
// Copyright (c) 2006-2011 by Lattice Semiconductor Corporation
// ALL RIGHTS RESERVED
// ------------------------------------------------------------------
//
// IMPORTANT: THIS FILE IS AUTO-GENERATED BY THE LATTICEMICO SYSTEM.
//
// Permission:
//
// Lattice Semiconductor grants permission to use this code
// pursuant to the terms of the Lattice Semiconductor Corporation
// Open Source License Agreement.
//
// Disclaimer:
//
// Lattice Semiconductor provides no warranty regarding the use or
// functionality of this code. It is the user's responsibility to
// verify the user's design for consistency and functionality through
// the use of formal verification methods.
//
// --------------------------------------------------------------------
//
// Lattice Semiconductor Corporation
// 5555 NE Moore Court
// Hillsboro, OR 97214
// U.S.A
//
// TEL: 1-800-Lattice (USA and Canada)
// 503-286-8001 (other locations)
//
// web: http://www.latticesemi.com/
// email: techsupport@latticesemi.com
//
// --------------------------------------------------------------------
// FILE DETAILS
// Project : LatticeMico32
// File : lm32_jtag.v
// Title : JTAG interface
// Dependencies : lm32_include.v
// Version : 6.1.17
// : Initial Release
// Version : 7.0SP2, 3.0
// : No Change
// Version : 3.1
// : No Change
// =============================================================================
`include "lm32_include.v"
`ifdef CFG_JTAG_ENABLED
`define LM32_DP 3'b000
`define LM32_TX 3'b001
`define LM32_RX 3'b010
// LM32 Debug Protocol commands IDs
`define LM32_DP_RNG 3:0
`define LM32_DP_READ_MEMORY 4'b0001
`define LM32_DP_WRITE_MEMORY 4'b0010
`define LM32_DP_READ_SEQUENTIAL 4'b0011
`define LM32_DP_WRITE_SEQUENTIAL 4'b0100
`define LM32_DP_WRITE_CSR 4'b0101
`define LM32_DP_BREAK 4'b0110
`define LM32_DP_RESET 4'b0111
// States for FSM
`define LM32_JTAG_STATE_RNG 3:0
`define LM32_JTAG_STATE_READ_COMMAND 4'h0
`define LM32_JTAG_STATE_READ_BYTE_0 4'h1
`define LM32_JTAG_STATE_READ_BYTE_1 4'h2
`define LM32_JTAG_STATE_READ_BYTE_2 4'h3
`define LM32_JTAG_STATE_READ_BYTE_3 4'h4
`define LM32_JTAG_STATE_READ_BYTE_4 4'h5
`define LM32_JTAG_STATE_PROCESS_COMMAND 4'h6
`define LM32_JTAG_STATE_WAIT_FOR_MEMORY 4'h7
`define LM32_JTAG_STATE_WAIT_FOR_CSR 4'h8
/////////////////////////////////////////////////////
// Module interface
/////////////////////////////////////////////////////
module lm32_jtag (
// ----- Inputs -------
clk_i,
rst_i,
jtag_clk,
jtag_update,
jtag_reg_q,
jtag_reg_addr_q,
`ifdef CFG_JTAG_UART_ENABLED
csr,
csr_write_enable,
csr_write_data,
stall_x,
`endif
`ifdef CFG_HW_DEBUG_ENABLED
jtag_read_data,
jtag_access_complete,
`endif
`ifdef CFG_DEBUG_ENABLED
exception_q_w,
`endif
// ----- Outputs -------
`ifdef CFG_JTAG_UART_ENABLED
jtx_csr_read_data,
jrx_csr_read_data,
`endif
`ifdef CFG_HW_DEBUG_ENABLED
jtag_csr_write_enable,
jtag_csr_write_data,
jtag_csr,
jtag_read_enable,
jtag_write_enable,
jtag_write_data,
jtag_address,
`endif
`ifdef CFG_DEBUG_ENABLED
jtag_break,
jtag_reset,
`endif
jtag_reg_d,
jtag_reg_addr_d
);
/////////////////////////////////////////////////////
// Inputs
/////////////////////////////////////////////////////
input clk_i; // Clock
input rst_i; // Reset
input jtag_clk; // JTAG clock
input jtag_update; // JTAG data register has been updated
input [`LM32_BYTE_RNG] jtag_reg_q; // JTAG data register
input [2:0] jtag_reg_addr_q; // JTAG data register
`ifdef CFG_JTAG_UART_ENABLED
input [`LM32_CSR_RNG] csr; // CSR to write
input csr_write_enable; // CSR write enable
input [`LM32_WORD_RNG] csr_write_data; // Data to write to specified CSR
input stall_x; // Stall instruction in X stage
`endif
`ifdef CFG_HW_DEBUG_ENABLED
input [`LM32_BYTE_RNG] jtag_read_data; // Data read from requested address
input jtag_access_complete; // Memory access if complete
`endif
`ifdef CFG_DEBUG_ENABLED
input exception_q_w; // Indicates an exception has occured in W stage
`endif
/////////////////////////////////////////////////////
// Outputs
/////////////////////////////////////////////////////
`ifdef CFG_JTAG_UART_ENABLED
output [`LM32_WORD_RNG] jtx_csr_read_data; // Value of JTX CSR for rcsr instructions
wire [`LM32_WORD_RNG] jtx_csr_read_data;
output [`LM32_WORD_RNG] jrx_csr_read_data; // Value of JRX CSR for rcsr instructions
wire [`LM32_WORD_RNG] jrx_csr_read_data;
`endif
`ifdef CFG_HW_DEBUG_ENABLED
output jtag_csr_write_enable; // CSR write enable
reg jtag_csr_write_enable;
output [`LM32_WORD_RNG] jtag_csr_write_data; // Data to write to specified CSR
wire [`LM32_WORD_RNG] jtag_csr_write_data;
output [`LM32_CSR_RNG] jtag_csr; // CSR to write
wire [`LM32_CSR_RNG] jtag_csr;
output jtag_read_enable; // Memory read enable
reg jtag_read_enable;
output jtag_write_enable; // Memory write enable
reg jtag_write_enable;
output [`LM32_BYTE_RNG] jtag_write_data; // Data to write to specified address
wire [`LM32_BYTE_RNG] jtag_write_data;
output [`LM32_WORD_RNG] jtag_address; // Memory read/write address
wire [`LM32_WORD_RNG] jtag_address;
`endif
`ifdef CFG_DEBUG_ENABLED
output jtag_break; // Request to raise a breakpoint exception
reg jtag_break;
output jtag_reset; // Request to raise a reset exception
reg jtag_reset;
`endif
output [`LM32_BYTE_RNG] jtag_reg_d;
reg [`LM32_BYTE_RNG] jtag_reg_d;
output [2:0] jtag_reg_addr_d;
wire [2:0] jtag_reg_addr_d;
/////////////////////////////////////////////////////
// Internal nets and registers
/////////////////////////////////////////////////////
reg rx_toggle; // Clock-domain crossing registers
reg rx_toggle_r; // Registered version of rx_toggle
reg rx_toggle_r_r; // Registered version of rx_toggle_r
reg rx_toggle_r_r_r; // Registered version of rx_toggle_r_r
reg [`LM32_BYTE_RNG] rx_byte;
reg [2:0] rx_addr;
`ifdef CFG_JTAG_UART_ENABLED
reg [`LM32_BYTE_RNG] uart_tx_byte; // UART TX data
reg uart_tx_valid; // TX data is valid
reg [`LM32_BYTE_RNG] uart_rx_byte; // UART RX data
reg uart_rx_valid; // RX data is valid
`endif
reg [`LM32_DP_RNG] command; // The last received command
`ifdef CFG_HW_DEBUG_ENABLED
reg [`LM32_BYTE_RNG] jtag_byte_0; // Registers to hold command paramaters
reg [`LM32_BYTE_RNG] jtag_byte_1;
reg [`LM32_BYTE_RNG] jtag_byte_2;
reg [`LM32_BYTE_RNG] jtag_byte_3;
reg [`LM32_BYTE_RNG] jtag_byte_4;
reg processing; // Indicates if we're still processing a memory read/write
`endif
reg [`LM32_JTAG_STATE_RNG] state; // Current state of FSM
/////////////////////////////////////////////////////
// Combinational Logic
/////////////////////////////////////////////////////
`ifdef CFG_HW_DEBUG_ENABLED
assign jtag_csr_write_data = {jtag_byte_0, jtag_byte_1, jtag_byte_2, jtag_byte_3};
assign jtag_csr = jtag_byte_4[`LM32_CSR_RNG];
assign jtag_address = {jtag_byte_0, jtag_byte_1, jtag_byte_2, jtag_byte_3};
assign jtag_write_data = jtag_byte_4;
`endif
// Generate status flags for reading via the JTAG interface
`ifdef CFG_JTAG_UART_ENABLED
assign jtag_reg_addr_d[1:0] = {uart_rx_valid, uart_tx_valid};
`else
assign jtag_reg_addr_d[1:0] = 2'b00;
`endif
`ifdef CFG_HW_DEBUG_ENABLED
assign jtag_reg_addr_d[2] = processing;
`else
assign jtag_reg_addr_d[2] = 1'b0;
`endif
`ifdef CFG_JTAG_UART_ENABLED
assign jtx_csr_read_data = {{`LM32_WORD_WIDTH-9{1'b0}}, uart_tx_valid, 8'h00};
assign jrx_csr_read_data = {{`LM32_WORD_WIDTH-9{1'b0}}, uart_rx_valid, uart_rx_byte};
`endif
/////////////////////////////////////////////////////
// Sequential Logic
/////////////////////////////////////////////////////
// Toggle a flag when a JTAG write occurs
always @(negedge jtag_update `CFG_RESET_SENSITIVITY)
begin
if (rst_i == `TRUE)
rx_toggle <= 1'b0;
else
rx_toggle <= ~rx_toggle;
end
always @(*)
begin
rx_byte = jtag_reg_q;
rx_addr = jtag_reg_addr_q;
end
// Clock domain crossing from JTAG clock domain to CPU clock domain
always @(posedge clk_i `CFG_RESET_SENSITIVITY)
begin
if (rst_i == `TRUE)
begin
rx_toggle_r <= 1'b0;
rx_toggle_r_r <= 1'b0;
rx_toggle_r_r_r <= 1'b0;
end
else
begin
rx_toggle_r <= rx_toggle;
rx_toggle_r_r <= rx_toggle_r;
rx_toggle_r_r_r <= rx_toggle_r_r;
end
end
// LM32 debug protocol state machine
always @(posedge clk_i `CFG_RESET_SENSITIVITY)
begin
if (rst_i == `TRUE)
begin
state <= `LM32_JTAG_STATE_READ_COMMAND;
command <= 4'b0000;
jtag_reg_d <= 8'h00;
`ifdef CFG_HW_DEBUG_ENABLED
processing <= `FALSE;
jtag_csr_write_enable <= `FALSE;
jtag_read_enable <= `FALSE;
jtag_write_enable <= `FALSE;
`endif
`ifdef CFG_DEBUG_ENABLED
jtag_break <= `FALSE;
jtag_reset <= `FALSE;
`endif
`ifdef CFG_JTAG_UART_ENABLED
uart_tx_byte <= 8'h00;
uart_tx_valid <= `FALSE;
uart_rx_byte <= 8'h00;
uart_rx_valid <= `FALSE;
`endif
end
else
begin
`ifdef CFG_JTAG_UART_ENABLED
if ((csr_write_enable == `TRUE) && (stall_x == `FALSE))
begin
case (csr)
`LM32_CSR_JTX:
begin
// Set flag indicating data is available
uart_tx_byte <= csr_write_data[`LM32_BYTE_0_RNG];
uart_tx_valid <= `TRUE;
end
`LM32_CSR_JRX:
begin
// Clear flag indidicating data has been received
uart_rx_valid <= `FALSE;
end
endcase
end
`endif
`ifdef CFG_DEBUG_ENABLED
// When an exception has occured, clear the requests
if (exception_q_w == `TRUE)
begin
jtag_break <= `FALSE;
jtag_reset <= `FALSE;
end
`endif
case (state)
`LM32_JTAG_STATE_READ_COMMAND:
begin
// Wait for rx register to toggle which indicates new data is available
if (rx_toggle_r_r != rx_toggle_r_r_r)
begin
command <= rx_byte[7:4];
case (rx_addr)
`ifdef CFG_DEBUG_ENABLED
`LM32_DP:
begin
case (rx_byte[7:4])
`ifdef CFG_HW_DEBUG_ENABLED
`LM32_DP_READ_MEMORY:
state <= `LM32_JTAG_STATE_READ_BYTE_0;
`LM32_DP_READ_SEQUENTIAL:
begin
{jtag_byte_2, jtag_byte_3} <= {jtag_byte_2, jtag_byte_3} + 1'b1;
state <= `LM32_JTAG_STATE_PROCESS_COMMAND;
end
`LM32_DP_WRITE_MEMORY:
state <= `LM32_JTAG_STATE_READ_BYTE_0;
`LM32_DP_WRITE_SEQUENTIAL:
begin
{jtag_byte_2, jtag_byte_3} <= {jtag_byte_2, jtag_byte_3} + 1'b1;
state <= 5;
end
`LM32_DP_WRITE_CSR:
state <= `LM32_JTAG_STATE_READ_BYTE_0;
`endif
`LM32_DP_BREAK:
begin
`ifdef CFG_JTAG_UART_ENABLED
uart_rx_valid <= `FALSE;
uart_tx_valid <= `FALSE;
`endif
jtag_break <= `TRUE;
end
`LM32_DP_RESET:
begin
`ifdef CFG_JTAG_UART_ENABLED
uart_rx_valid <= `FALSE;
uart_tx_valid <= `FALSE;
`endif
jtag_reset <= `TRUE;
end
endcase
end
`endif
`ifdef CFG_JTAG_UART_ENABLED
`LM32_TX:
begin
uart_rx_byte <= rx_byte;
uart_rx_valid <= `TRUE;
end
`LM32_RX:
begin
jtag_reg_d <= uart_tx_byte;
uart_tx_valid <= `FALSE;
end
`endif
default:
;
endcase
end
end
`ifdef CFG_HW_DEBUG_ENABLED
`LM32_JTAG_STATE_READ_BYTE_0:
begin
if (rx_toggle_r_r != rx_toggle_r_r_r)
begin
jtag_byte_0 <= rx_byte;
state <= `LM32_JTAG_STATE_READ_BYTE_1;
end
end
`LM32_JTAG_STATE_READ_BYTE_1:
begin
if (rx_toggle_r_r != rx_toggle_r_r_r)
begin
jtag_byte_1 <= rx_byte;
state <= `LM32_JTAG_STATE_READ_BYTE_2;
end
end
`LM32_JTAG_STATE_READ_BYTE_2:
begin
if (rx_toggle_r_r != rx_toggle_r_r_r)
begin
jtag_byte_2 <= rx_byte;
state <= `LM32_JTAG_STATE_READ_BYTE_3;
end
end
`LM32_JTAG_STATE_READ_BYTE_3:
begin
if (rx_toggle_r_r != rx_toggle_r_r_r)
begin
jtag_byte_3 <= rx_byte;
if (command == `LM32_DP_READ_MEMORY)
state <= `LM32_JTAG_STATE_PROCESS_COMMAND;
else
state <= `LM32_JTAG_STATE_READ_BYTE_4;
end
end
`LM32_JTAG_STATE_READ_BYTE_4:
begin
if (rx_toggle_r_r != rx_toggle_r_r_r)
begin
jtag_byte_4 <= rx_byte;
state <= `LM32_JTAG_STATE_PROCESS_COMMAND;
end
end
`LM32_JTAG_STATE_PROCESS_COMMAND:
begin
case (command)
`LM32_DP_READ_MEMORY,
`LM32_DP_READ_SEQUENTIAL:
begin
jtag_read_enable <= `TRUE;
processing <= `TRUE;
state <= `LM32_JTAG_STATE_WAIT_FOR_MEMORY;
end
`LM32_DP_WRITE_MEMORY,
`LM32_DP_WRITE_SEQUENTIAL:
begin
jtag_write_enable <= `TRUE;
processing <= `TRUE;
state <= `LM32_JTAG_STATE_WAIT_FOR_MEMORY;
end
`LM32_DP_WRITE_CSR:
begin
jtag_csr_write_enable <= `TRUE;
processing <= `TRUE;
state <= `LM32_JTAG_STATE_WAIT_FOR_CSR;
end
endcase
end
`LM32_JTAG_STATE_WAIT_FOR_MEMORY:
begin
if (jtag_access_complete == `TRUE)
begin
jtag_read_enable <= `FALSE;
jtag_reg_d <= jtag_read_data;
jtag_write_enable <= `FALSE;
processing <= `FALSE;
state <= `LM32_JTAG_STATE_READ_COMMAND;
end
end
`LM32_JTAG_STATE_WAIT_FOR_CSR:
begin
jtag_csr_write_enable <= `FALSE;
processing <= `FALSE;
state <= `LM32_JTAG_STATE_READ_COMMAND;
end
`endif
endcase
end
end
endmodule
`endif
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