Improved icestorm example

9 files changed, 226 insertions, 76 deletions

diff --git a/scripts/icestorm/Makefile b/scripts/icestorm/Makefile
new file mode 100644
index 0000000..296c8ed
--- /dev/null
+++ b/scripts/icestorm/Makefile
@@ -0,0 +1,42 @@
+
+TOOLCHAIN_PREFIX = riscv64-unknown-elf-
+ICECUBE_DIR = /opt/lscc/iCEcube2.2014.08
+
+all: example.bin
+
+firmware.elf: firmware.S firmware.c firmware.lds
+	$(TOOLCHAIN_PREFIX)gcc -Os -m32 -ffreestanding -nostdlib -o firmware.elf firmware.S firmware.c \
+			--std=gnu99 -Wl,-Bstatic,-T,firmware.lds,-Map,firmware.map,--strip-debug -lgcc
+
+firmware.bin: firmware.elf
+	$(TOOLCHAIN_PREFIX)objcopy -O binary firmware.elf firmware.bin
+
+firmware.hex: firmware.bin
+	python3 ../../firmware/makehex.py firmware.bin 128 > firmware.hex
+
+synth.blif: example.v firmware.hex
+	yosys -v3 -l synth.log -p 'synth_ice40 -top top -blif synth.blif; write_verilog -attr2comment synth.v' ../../picorv32.v example.v
+
+example.txt: synth.blif
+	arachne-pnr -d 8k -o example.txt -p example.pcf synth.blif
+
+example.bin: example.txt
+	icepack example.txt example.bin
+
+example_tb.exe: example_tb.v example.v firmware.hex
+	iverilog -o example_tb.exe -s testbench example.v example_tb.v ../../picorv32.v # $(ICECUBE_DIR)/verilog/sb_ice_syn.v
+	chmod -x example_tb.exe
+
+sim: example_tb.exe
+	vvp -N example_tb.exe # +vcd
+
+prog_sram:
+	iceprog -S example.bin
+
+clean:
+	rm -f firmware.elf firmware.map firmware.bin firmware.hex
+	rm -f synth.log synth.v synth.blif example.txt example.bin
+	rm -f example_tb.exe example.vcd
+
+.PHONY: all sim prog_sram clean
+
diff --git a/scripts/icestorm/build.sh b/scripts/icestorm/build.sh
deleted file mode 100644
index cdefd04..0000000
--- a/scripts/icestorm/build.sh
+++ /dev/null
@@ -1,6 +0,0 @@
-#!/bin/bash
-set -ex
-echo -n > firmware.hex
-yosys -l synth.log -p 'synth_ice40 -top top -blif synth.blif' ../../picorv32.v top.v
-arachne-pnr -d 8k -o synth.txt synth.blif
-icepack synth.txt synth.bin
diff --git a/scripts/icestorm/example.pcf b/scripts/icestorm/example.pcf
new file mode 100644
index 0000000..5f21bd6
--- /dev/null
+++ b/scripts/icestorm/example.pcf
@@ -0,0 +1,9 @@
+set_io LED0 B5
+set_io LED1 B4
+set_io LED2 A2
+set_io LED3 A1
+set_io LED4 C5
+set_io LED5 C4
+set_io LED6 B3
+set_io LED7 C3
+set_io clk_pin J3
diff --git a/scripts/icestorm/example.v b/scripts/icestorm/example.v
new file mode 100644
index 0000000..5c40661
--- /dev/null
+++ b/scripts/icestorm/example.v
@@ -0,0 +1,94 @@
+`timescale 1 ns / 1 ps
+
+module top (
+	input clk_pin,
+	output reg LED0, LED1, LED2, LED3, LED4, LED5, LED6, LED7
+);
+	// -------------------------------
+	// Clock Buffer
+
+	wire clk;
+
+`ifdef USE_SB_GB_IO
+	SB_GB_IO #(
+		.PIN_TYPE(6'b 0000_01)
+	) clk_gb (
+		.PACKAGE_PIN(clk_pin),
+		.GLOBAL_BUFFER_OUTPUT(clk)
+	);
+`else
+	assign clk = clk_pin;
+`endif
+
+	// -------------------------------
+	// Reset Generator
+
+	reg [7:0] resetn_counter = 0;
+	wire resetn = &resetn_counter;
+
+	always @(posedge clk) begin
+		if (!resetn)
+			resetn_counter <= resetn_counter + 1;
+	end
+
+	// -------------------------------
+	// PicoRV32 Core
+
+	wire mem_valid;
+	wire [31:0] mem_addr;
+	wire [31:0] mem_wdata;
+	wire [3:0] mem_wstrb;
+
+	reg mem_ready;
+	reg [31:0] mem_rdata;
+
+	picorv32 #(
+		.ENABLE_COUNTERS(0),
+		.LATCHED_MEM_RDATA(1),
+		.TWO_STAGE_SHIFT(0),
+		.TWO_CYCLE_ALU(1),
+		.CATCH_MISALIGN(0),
+		.CATCH_ILLINSN(0)
+	) cpu (
+		.clk      (clk      ),
+		.resetn   (resetn   ),
+		.mem_valid(mem_valid),
+		.mem_ready(mem_ready),
+		.mem_addr (mem_addr ),
+		.mem_wdata(mem_wdata),
+		.mem_wstrb(mem_wstrb),
+		.mem_rdata(mem_rdata)
+	);
+
+	// -------------------------------
+	// Memory/IO Interface
+
+	// 128 32bit words = 512 bytes memory
+	localparam MEM_SIZE = 128;
+	reg [31:0] memory [0:MEM_SIZE-1];
+	initial $readmemh("firmware.hex", memory);
+
+	always @(posedge clk) begin
+		mem_ready <= 0;
+		if (resetn && mem_valid && !mem_ready) begin
+			(* parallel_case *)
+			case (1)
+				!mem_wstrb && (mem_addr >> 2) < MEM_SIZE: begin
+					mem_rdata <= memory[mem_addr >> 2];
+					mem_ready <= 1;
+				end
+				|mem_wstrb && (mem_addr >> 2) < MEM_SIZE: begin
+					if (mem_wstrb[0]) memory[mem_addr >> 2][ 7: 0] <= mem_wdata[ 7: 0];
+					if (mem_wstrb[1]) memory[mem_addr >> 2][15: 8] <= mem_wdata[15: 8];
+					if (mem_wstrb[2]) memory[mem_addr >> 2][23:16] <= mem_wdata[23:16];
+					if (mem_wstrb[3]) memory[mem_addr >> 2][31:24] <= mem_wdata[31:24];
+					mem_ready <= 1;
+				end
+				|mem_wstrb && mem_addr == 32'h1000_0000: begin
+					{LED7, LED6, LED5, LED4, LED3, LED2, LED1, LED0} <= mem_wdata;
+					mem_ready <= 1;
+				end
+			endcase
+		end
+	end
+endmodule
diff --git a/scripts/icestorm/example_tb.v b/scripts/icestorm/example_tb.v
new file mode 100644
index 0000000..7fda120
--- /dev/null
+++ b/scripts/icestorm/example_tb.v
@@ -0,0 +1,30 @@
+`timescale 1 ns / 1 ps
+
+module testbench;
+	reg clk_pin = 1;
+	always #5 clk_pin = ~clk_pin;
+	wire LED0, LED1, LED2, LED3, LED4, LED5, LED6, LED7;
+
+	top uut (
+		.clk_pin(clk_pin),
+		.LED0(LED0),
+		.LED1(LED1),
+		.LED2(LED2),
+		.LED3(LED3),
+		.LED4(LED4),
+		.LED5(LED5),
+		.LED6(LED6),
+		.LED7(LED7)
+	);
+
+	initial begin
+		if ($test$plusargs("vcd")) begin
+			$dumpfile("example.vcd");
+			$dumpvars(0, testbench);
+		end
+
+		$monitor(LED7, LED6, LED5, LED4, LED3, LED2, LED1, LED0);
+		repeat (10000000) @(posedge clk_pin);
+		$finish;
+	end
+endmodule
diff --git a/scripts/icestorm/firmware.S b/scripts/icestorm/firmware.S
new file mode 100644
index 0000000..e6c6e42
--- /dev/null
+++ b/scripts/icestorm/firmware.S
@@ -0,0 +1,12 @@
+.section .init
+.global main
+
+/* set stack pointer */
+lui sp, %hi(512)
+addi sp, sp, %lo(512)
+
+/* call main */
+jal ra, main
+
+/* break */
+sbreak
diff --git a/scripts/icestorm/firmware.c b/scripts/icestorm/firmware.c
new file mode 100644
index 0000000..b400ba0
--- /dev/null
+++ b/scripts/icestorm/firmware.c
@@ -0,0 +1,28 @@
+#include <stdint.h>
+
+#define SHIFT_COUNTER_BITS 16
+
+void output(uint8_t c)
+{
+	*(volatile char*)0x10000000 = c;
+}
+
+void output_gray(uint8_t c)
+{
+	unsigned int in_buf = c, out_buf = 0;
+	for (int i = 0; i < 8; i++) {
+		unsigned int bit = (in_buf & 1) ^ ((in_buf >> 1) & 1);
+		in_buf = in_buf >> 1;
+		out_buf = (out_buf << 1) | bit;
+	}
+	output(out_buf);
+}
+
+void main()
+{
+	for (uint32_t counter = (2+4+32+64) << SHIFT_COUNTER_BITS;; counter++) {
+		asm volatile ("" : : "r"(counter));
+		if ((counter & ~(~0 << SHIFT_COUNTER_BITS)) == 0)
+			output_gray(counter >> SHIFT_COUNTER_BITS);
+	}
+}
diff --git a/scripts/icestorm/firmware.lds b/scripts/icestorm/firmware.lds
new file mode 100644
index 0000000..970000a
--- /dev/null
+++ b/scripts/icestorm/firmware.lds
@@ -0,0 +1,11 @@
+SECTIONS {
+	.memory : {
+		. = 0x000000;
+		*(.init);
+		*(.text);
+		*(*);
+		. = ALIGN(4);
+		end = .;
+	}
+}
+
diff --git a/scripts/icestorm/top.v b/scripts/icestorm/top.v
deleted file mode 100644
index 026321d..0000000
--- a/scripts/icestorm/top.v
+++ /dev/null
@@ -1,70 +0,0 @@
-`timescale 1 ns / 1 ps
-
-module top (
-	input            clk,
-	input            resetn,
-	output           trap,
-	output reg [7:0] out_byte,
-	output reg       out_byte_en
-);
-	// 1024 32bit words = 4kB memory
-	parameter MEM_SIZE = 1024;
-
-	wire mem_valid;
-	wire mem_instr;
-	wire mem_ready;
-	wire [31:0] mem_addr;
-	wire [31:0] mem_wdata;
-	wire [3:0] mem_wstrb;
-	reg [31:0] mem_rdata;
-
-	wire mem_la_read;
-	wire mem_la_write;
-	wire [31:0] mem_la_addr;
-	wire [31:0] mem_la_wdata;
-	wire [3:0] mem_la_wstrb;
-
-	picorv32 #(
-		.ENABLE_COUNTERS(0),
-		.TWO_STAGE_SHIFT(0),
-		.CATCH_MISALIGN(0),
-		.CATCH_ILLINSN(0)
-	) uut (
-		.clk         (clk         ),
-		.resetn      (resetn      ),
-		.trap        (trap        ),
-		.mem_valid   (mem_valid   ),
-		.mem_instr   (mem_instr   ),
-		.mem_ready   (mem_ready   ),
-		.mem_addr    (mem_addr    ),
-		.mem_wdata   (mem_wdata   ),
-		.mem_wstrb   (mem_wstrb   ),
-		.mem_rdata   (mem_rdata   ),
-		.mem_la_read (mem_la_read ),
-		.mem_la_write(mem_la_write),
-		.mem_la_addr (mem_la_addr ),
-		.mem_la_wdata(mem_la_wdata),
-		.mem_la_wstrb(mem_la_wstrb)
-	);
-
-	reg [31:0] memory [0:MEM_SIZE-1];
-	initial $readmemh("firmware.hex", memory);
-
-	assign mem_ready = 1;
-
-	always @(posedge clk) begin
-		out_byte_en <= 0;
-		mem_rdata <= memory[mem_la_addr >> 2];
-		if (mem_la_write && (mem_la_addr >> 2) < MEM_SIZE) begin
-			if (mem_la_wstrb[0]) memory[mem_la_addr >> 2][ 7: 0] <= mem_la_wdata[ 7: 0];
-			if (mem_la_wstrb[1]) memory[mem_la_addr >> 2][15: 8] <= mem_la_wdata[15: 8];
-			if (mem_la_wstrb[2]) memory[mem_la_addr >> 2][23:16] <= mem_la_wdata[23:16];
-			if (mem_la_wstrb[3]) memory[mem_la_addr >> 2][31:24] <= mem_la_wdata[31:24];
-		end
-		else
-		if (mem_la_write && mem_la_addr == 32'h1000_0000) begin
-			out_byte_en <= 1;
-			out_byte <= mem_la_wdata;
-		end
-	end
-endmodule