WIP: add WISHBONE interconnect support

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>

1 files changed, 202 insertions, 0 deletions

diff --git a/picorv32.v b/picorv32.v
index e3dd708..28d7027 100644
--- a/picorv32.v
+++ b/picorv32.v
@@ -2547,3 +2547,205 @@ module picorv32_axi_adapter (
 	end
 endmodule
 
+
+/***************************************************************
+ * picorv32_wb
+ ***************************************************************/
+
+module picorv32_wb #(
+	parameter [ 0:0] ENABLE_COUNTERS = 1,
+	parameter [ 0:0] ENABLE_COUNTERS64 = 1,
+	parameter [ 0:0] ENABLE_REGS_16_31 = 1,
+	parameter [ 0:0] ENABLE_REGS_DUALPORT = 1,
+	parameter [ 0:0] TWO_STAGE_SHIFT = 1,
+	parameter [ 0:0] BARREL_SHIFTER = 0,
+	parameter [ 0:0] TWO_CYCLE_COMPARE = 0,
+	parameter [ 0:0] TWO_CYCLE_ALU = 0,
+	parameter [ 0:0] COMPRESSED_ISA = 0,
+	parameter [ 0:0] CATCH_MISALIGN = 1,
+	parameter [ 0:0] CATCH_ILLINSN = 1,
+	parameter [ 0:0] ENABLE_PCPI = 0,
+	parameter [ 0:0] ENABLE_MUL = 0,
+	parameter [ 0:0] ENABLE_FAST_MUL = 0,
+	parameter [ 0:0] ENABLE_DIV = 0,
+	parameter [ 0:0] ENABLE_IRQ = 0,
+	parameter [ 0:0] ENABLE_IRQ_QREGS = 1,
+	parameter [ 0:0] ENABLE_IRQ_TIMER = 1,
+	parameter [ 0:0] ENABLE_TRACE = 0,
+	parameter [ 0:0] REGS_INIT_ZERO = 0,
+	parameter [31:0] MASKED_IRQ = 32'h 0000_0000,
+	parameter [31:0] LATCHED_IRQ = 32'h ffff_ffff,
+	parameter [31:0] PROGADDR_RESET = 32'h 0000_0000,
+	parameter [31:0] PROGADDR_IRQ = 32'h 0000_0010,
+	parameter [31:0] STACKADDR = 32'h ffff_ffff
+) (
+	output trap,
+
+	// Wishbone interfaces
+	input wb_rst_i,
+	input wb_clk_i,
+
+	output reg [31:0] wbm_adr_o,
+	output reg [31:0] wbm_dat_o,
+	input [31:0] wbm_dat_i,
+	output reg wbm_we_o,
+	output reg [3:0] wbm_sel_o,
+	output reg wbm_stb_o,
+	input wbm_ack_i,
+	output reg wbm_cyc_o,
+
+	// Pico Co-Processor Interface (PCPI)
+	output        pcpi_valid,
+	output [31:0] pcpi_insn,
+	output [31:0] pcpi_rs1,
+	output [31:0] pcpi_rs2,
+	input         pcpi_wr,
+	input  [31:0] pcpi_rd,
+	input         pcpi_wait,
+	input         pcpi_ready,
+
+	// IRQ interface
+	input  [31:0] irq,
+	output [31:0] eoi,
+
+	// Trace Interface
+	output        trace_valid,
+	output [35:0] trace_data
+);
+	wire        mem_valid;
+	wire [31:0] mem_addr;
+	wire [31:0] mem_wdata;
+	wire [ 3:0] mem_wstrb;
+	wire        mem_instr;
+	reg         mem_ready;
+	reg [31:0] mem_rdata;
+
+	wire clk;
+	wire resetn;
+
+	assign clk = wb_clk_i;
+	assign resetn = ~wb_rst_i;
+
+	picorv32 #(
+		.ENABLE_COUNTERS     (ENABLE_COUNTERS     ),
+		.ENABLE_COUNTERS64   (ENABLE_COUNTERS64   ),
+		.ENABLE_REGS_16_31   (ENABLE_REGS_16_31   ),
+		.ENABLE_REGS_DUALPORT(ENABLE_REGS_DUALPORT),
+		.TWO_STAGE_SHIFT     (TWO_STAGE_SHIFT     ),
+		.BARREL_SHIFTER      (BARREL_SHIFTER      ),
+		.TWO_CYCLE_COMPARE   (TWO_CYCLE_COMPARE   ),
+		.TWO_CYCLE_ALU       (TWO_CYCLE_ALU       ),
+		.COMPRESSED_ISA      (COMPRESSED_ISA      ),
+		.CATCH_MISALIGN      (CATCH_MISALIGN      ),
+		.CATCH_ILLINSN       (CATCH_ILLINSN       ),
+		.ENABLE_PCPI         (ENABLE_PCPI         ),
+		.ENABLE_MUL          (ENABLE_MUL          ),
+		.ENABLE_FAST_MUL     (ENABLE_FAST_MUL     ),
+		.ENABLE_DIV          (ENABLE_DIV          ),
+		.ENABLE_IRQ          (ENABLE_IRQ          ),
+		.ENABLE_IRQ_QREGS    (ENABLE_IRQ_QREGS    ),
+		.ENABLE_IRQ_TIMER    (ENABLE_IRQ_TIMER    ),
+		.ENABLE_TRACE        (ENABLE_TRACE        ),
+		.REGS_INIT_ZERO      (REGS_INIT_ZERO      ),
+		.MASKED_IRQ          (MASKED_IRQ          ),
+		.LATCHED_IRQ         (LATCHED_IRQ         ),
+		.PROGADDR_RESET      (PROGADDR_RESET      ),
+		.PROGADDR_IRQ        (PROGADDR_IRQ        ),
+		.STACKADDR           (STACKADDR           )
+	) picorv32_core (
+		.clk      (clk   ),
+		.resetn   (resetn),
+		.trap     (trap  ),
+
+		.mem_valid(mem_valid),
+		.mem_addr (mem_addr ),
+		.mem_wdata(mem_wdata),
+		.mem_wstrb(mem_wstrb),
+		.mem_instr(mem_instr),
+		.mem_ready(mem_ready),
+		.mem_rdata(mem_rdata),
+
+		.pcpi_valid(pcpi_valid),
+		.pcpi_insn (pcpi_insn ),
+		.pcpi_rs1  (pcpi_rs1  ),
+		.pcpi_rs2  (pcpi_rs2  ),
+		.pcpi_wr   (pcpi_wr   ),
+		.pcpi_rd   (pcpi_rd   ),
+		.pcpi_wait (pcpi_wait ),
+		.pcpi_ready(pcpi_ready),
+
+		.irq(irq),
+		.eoi(eoi),
+
+		.trace_valid(trace_valid),
+		.trace_data (trace_data)
+	);
+
+	localparam IDLE = 2'b00;
+	localparam WBSTART = 2'b01;
+	localparam WBEND = 2'b10;
+
+	reg [1:0] state;
+
+	wire we;
+	assign we = (mem_wstrb[0] | mem_wstrb[1] | mem_wstrb[2] | mem_wstrb[3]);
+
+	always @(posedge wb_clk_i)
+	if (wb_rst_i)
+	begin
+		wbm_adr_o <= 0;
+		wbm_dat_o <= 0;
+		wbm_we_o <= 0;
+		wbm_sel_o <= 0;
+		wbm_stb_o <= 0;
+		wbm_cyc_o <= 0;
+		state <= IDLE;
+	end
+	else
+	begin
+		case (state)
+		IDLE:
+			if (mem_valid)
+			begin
+				wbm_adr_o <= mem_addr;
+				wbm_dat_o <= mem_wdata;
+				wbm_we_o <= we;
+				wbm_sel_o <= mem_wstrb;
+
+				wbm_stb_o <= 1'b1;
+				wbm_cyc_o <= 1'b1;
+				state <= WBSTART;
+			end
+			else
+			begin
+				mem_ready <= 1'b0;
+
+				wbm_stb_o <= 1'b0;
+				wbm_cyc_o <= 1'b0;
+				wbm_we_o <= 1'b0;
+			end
+		WBSTART:
+			if (wbm_ack_i)
+			begin
+				mem_rdata <= wbm_dat_i;
+				mem_ready <= 1'b1;
+
+				state <= WBEND;
+
+				wbm_stb_o <= 1'b0;
+				wbm_cyc_o <= 1'b0;
+				wbm_we_o <= 1'b0;
+			end
+
+		WBEND:
+			begin
+				mem_ready <= 1'b0;
+
+				state <= IDLE;
+			end
+
+		default:
+			state <= IDLE;
+		endcase
+	end
+endmodule