Refactor picosoc code

picosoc/.gitignore

@@ -6,8 +6,8 @@
 /firmware_vma.elf
 /firmware.hex
 /firmware.bin
-/design.asc
+/hx8kdemo.asc
-/design.bin
+/hx8kdemo.bin
-/design.blif
+/hx8kdemo.blif
-/design.log
+/hx8kdemo.log
-/design.rpt
+/hx8kdemo.rpt

picosoc/Makefile

@@ -1,4 +1,6 @@
 
+# ---- Generic Testbenches ----
+
 testbench: testbench.vvp firmware.hex
 	vvp -N $<
 
@@ -11,10 +13,24 @@ spiflash_tb: spiflash_tb.vvp firmware.hex
 spiflash_tb.vvp: spiflash.v spiflash_tb.v
 	iverilog -s testbench -o $@ $^
 
-prog: design.bin firmware.bin
+# ---- iCE40 HX8K Breakout Board ----
-	iceprog design.bin
+
+hx8kprog: hx8kdemo.bin firmware.bin
+	iceprog hx8kdemo.bin
 	iceprog -o 1M firmware.bin
 
+hx8kdemo.blif: hx8kdemo.v spimemio.v picosoc.v ../picorv32.v
+	yosys -ql hx8kdemo.log -p 'synth_ice40 -top hx8kdemo -blif hx8kdemo.blif' $^
+
+hx8kdemo.asc: hx8kdemo.pcf hx8kdemo.blif
+	arachne-pnr -d 8k -o hx8kdemo.asc -p hx8kdemo.pcf hx8kdemo.blif
+
+hx8kdemo.bin: hx8kdemo.asc
+	icetime -d hx8k -c 12 -mtr hx8kdemo.rpt hx8kdemo.asc
+	icepack hx8kdemo.asc hx8kdemo.bin
+
+# ---- Example Firmware ----
+
 firmware.elf: firmware.s
 	riscv32-unknown-elf-gcc -c -o firmware.elf firmware.s
 
@@ -27,20 +43,12 @@ firmware.hex: firmware_vma.elf
 firmware.bin: firmware.elf
 	riscv32-unknown-elf-objcopy -O binary firmware.elf firmware.bin
 
-design.blif: spimemio.v picosoc.v ../picorv32.v
+# ---- Clean ----
-	yosys -ql design.log -p 'synth_ice40 -top picosoc -blif design.blif' $^
-
-design.asc: pinout.pcf design.blif
-	arachne-pnr -d 8k -o design.asc -p pinout.pcf design.blif
-
-design.bin: design.asc
-	icetime -d hx8k -c 12 -mtr design.rpt design.asc
-	icepack design.asc design.bin
 
 clean:
 	rm -f testbench.vvp testbench.vcd spiflash_tb.vvp spiflash_tb.vcd
 	rm -f firmware.elf firmware_vma.elf firmware.hex firmware.bin
-	rm -f design.blif design.log design.asc design.rpt design.bin
+	rm -f hx8kdemo.blif hx8kdemo.log hx8kdemo.asc hx8kdemo.rpt hx8kdemo.bin
 
-.PHONY: testbench spiflash_tb prog clean
+.PHONY: testbench spiflash_tb hx8kprog clean
 

picosoc/README.md

@@ -5,11 +5,11 @@ PicoSoC - A simple example SoC using PicoRV32
 This is a simple PicoRV32 example design that can run code directly from an SPI
 flash chip. This example design uses the Lattice iCE40-HX8K Breakout Board.
 
-The flash is mapped to the memory region starting at 0x80000000. The reset
+The flash is mapped to the memory region starting at 0x01000000. The reset
-vector is set to 0x80100000, i.e. at the 1MB offset inside the flash memory.
+vector is set to 0x01100000, i.e. at the 1MB offset inside the flash memory.
 
 A small scratchpad memory (default 256 words, i.e. 1 kB) is mapped to address
-0x00000000. A simple GPIO controller is mapped to address 0xC0000000.
+0x00000000.
 
 Run `make test` to run the test bench (and create `testbench.vcd`).
 
@@ -17,11 +17,13 @@ Run `make prog` to build the configuration bit-stream and firmware images
 and upload them to a connected iCE40-HX8K Breakout Board.
 
 | File                          | Description                                                     |
-| --------------------------- | --------------------------------------------------------------- |
+| ----------------------------- | --------------------------------------------------------------- |
-| [picosoc.v](picosoc.v)      | Top-level Verilog module for the design                         |
+| [picosoc.v](picosoc.v)        | Top-level PicoSoC Verilog module                                |
+| [picosoc.v](picosoc.v)        | Top-level PicoSoC Verilog module                                |
 | [spimemio.v](spimemio.v)      | Memory controller that interfaces to external SPI flash         |
 | [spiflash.v](spiflash.v)      | Simulation model of an SPI flash (used by testbench.v)          |
 | [testbench.v](testbench.v)    | Simple test bench for the design (requires firmware.hex).       |
 | [firmware.s](firmware.s)      | Assembler source for firmware.hex/firmware.bin.                 |
-| [pinout.pcf](pinout.pcf)    | Pin constraints for implementation on iCE40-HX8K Breakout Board |
+| [hx8kdemo.v](hx8kdemo.v)      | FPGA-based example implementation on iCE40-HX8K Breakout Board  |
+| [hx8kdemo.pcf](hx8kdemo.pcf)  | Pin constraints for implementation on iCE40-HX8K Breakout Board |
 

picosoc/firmware.s

@@ -23,7 +23,7 @@ li      x5,0x00008067   # ret
 sw      x5,80(x0)
 
 # setup gpio address in x5
-li      x5,0xc0000000
+li      x5,0x02000000
 sw      x0,0(x5)
 
 # initial entry point into RAM code

picosoc/hx8kdemo.pcf

@@ -0,0 +1,24 @@
+
+# Pinout for the iCE40-HX8K Breakout Board
+
+set_io clk J3
+
+set_io flash_csb R12
+set_io flash_clk R11
+set_io flash_io0 P12
+set_io flash_io1 P11
+set_io flash_io2 T9  # center on J3
+set_io flash_io3 P8  # center on J3
+
+set_io ser_tx B12
+set_io ser_rx B10
+
+set_io leds[0] B5  # LED0
+set_io leds[1] B4  # LED1
+set_io leds[2] A2  # LED2
+set_io leds[3] A1  # LED3
+set_io leds[4] C5  # LED4
+set_io leds[5] C4  # LED5
+set_io leds[6] B3  # LED6
+set_io leds[7] C3  # LED7
+

picosoc/hx8kdemo.v

@@ -0,0 +1,109 @@
+/*
+ *  PicoSoC - A simple example SoC using PicoRV32
+ *
+ *  Copyright (C) 2017  Clifford Wolf <clifford@clifford.at>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+module hx8kdemo (
+	input clk,
+
+	input ser_tx,
+	input ser_rx,
+
+	output [7:0] leds,
+
+	output flash_csb,
+	output flash_clk,
+	inout  flash_io0,
+	inout  flash_io1,
+	inout  flash_io2,
+	inout  flash_io3
+);
+	reg [5:0] reset_cnt = 0;
+	wire resetn = &reset_cnt;
+
+	always @(posedge clk) begin
+		reset_cnt <= reset_cnt + !resetn;
+	end
+
+	wire flash_io0_oe, flash_io0_do, flash_io0_di;
+	wire flash_io1_oe, flash_io1_do, flash_io1_di;
+	wire flash_io2_oe, flash_io2_do, flash_io2_di;
+	wire flash_io3_oe, flash_io3_do, flash_io3_di;
+
+	SB_IO #(
+		.PIN_TYPE(6'b 1010_01),
+		.PULLUP(1'b 0)
+	) flash_io_buf [3:0] (
+		.PACKAGE_PIN({flash_io3, flash_io2, flash_io1, flash_io0}),
+		.OUTPUT_ENABLE({flash_io3_oe, flash_io2_oe, flash_io1_oe, flash_io0_oe}),
+		.D_OUT_0({flash_io3_do, flash_io2_do, flash_io1_do, flash_io0_do}),
+		.D_IN_0({flash_io3_di, flash_io2_di, flash_io1_di, flash_io0_di})
+	);
+
+	wire        iomem_valid;
+	reg         iomem_ready;
+	wire [3:0]  iomem_wstrb;
+	wire [31:0] iomem_addr;
+	wire [31:0] iomem_wdata;
+	reg  [31:0] iomem_rdata;
+
+	reg [31:0] gpio;
+
+	assign leds = gpio >> 12;
+
+	always @(posedge clk) begin
+		iomem_ready <= 0;
+		if (iomem_valid && !iomem_ready && iomem_addr[31:24] == 8'h 02) begin
+			iomem_ready <= 1;
+			iomem_rdata <= gpio;
+			if (iomem_wstrb[0]) gpio[ 7: 0] <= iomem_wdata[ 7: 0];
+			if (iomem_wstrb[1]) gpio[15: 8] <= iomem_wdata[15: 8];
+			if (iomem_wstrb[2]) gpio[23:16] <= iomem_wdata[23:16];
+			if (iomem_wstrb[3]) gpio[31:24] <= iomem_wdata[31:24];
+		end
+	end
+
+	picosoc uut (
+		.clk          (clk         ),
+		.resetn       (resetn      ),
+
+		.flash_csb    (flash_csb   ),
+		.flash_clk    (flash_clk   ),
+
+		.flash_io0_oe (flash_io0_oe),
+		.flash_io1_oe (flash_io1_oe),
+		.flash_io2_oe (flash_io2_oe),
+		.flash_io3_oe (flash_io3_oe),
+
+		.flash_io0_do (flash_io0_do),
+		.flash_io1_do (flash_io1_do),
+		.flash_io2_do (flash_io2_do),
+		.flash_io3_do (flash_io3_do),
+
+		.flash_io0_di (flash_io0_di),
+		.flash_io1_di (flash_io1_di),
+		.flash_io2_di (flash_io2_di),
+		.flash_io3_di (flash_io3_di),
+
+		.iomem_valid  (iomem_valid ),
+		.iomem_ready  (iomem_ready ),
+		.iomem_wstrb  (iomem_wstrb ),
+		.iomem_addr   (iomem_addr  ),
+		.iomem_wdata  (iomem_wdata ),
+		.iomem_rdata  (iomem_rdata )
+	);
+endmodule

picosoc/picosoc.v

@@ -19,93 +19,111 @@
 
 module picosoc (
 	input clk,
-	output trap,
+	input resetn,
 
-	input [31:0] gpio_i,
+	output        iomem_valid,
-	output reg [31:0] gpio_o,
+	input         iomem_ready,
+	output [ 3:0] iomem_wstrb,
+	output [31:0] iomem_addr,
+	output [31:0] iomem_wdata,
+	input  [31:0] iomem_rdata,
 
 	output flash_csb,
 	output flash_clk,
-	output flash_io0,
+
-	input  flash_io1,
+	output flash_io0_oe,
-	input  flash_io2,
+	output flash_io1_oe,
-	input  flash_io3
+	output flash_io2_oe,
+	output flash_io3_oe,
+
+	output flash_io0_do,
+	output flash_io1_do,
+	output flash_io2_do,
+	output flash_io3_do,
+
+	input  flash_io0_di,
+	input  flash_io1_di,
+	input  flash_io2_di,
+	input  flash_io3_di
 );
 	parameter integer MEM_WORDS = 256;
 	parameter [31:0] STACKADDR = (4*MEM_WORDS);       // end of memory
-	parameter [31:0] PROGADDR_RESET = 32'h 8010_0000; // 1 MB into flash
+	parameter [31:0] PROGADDR_RESET = 32'h 0110_0000; // 1 MB into flash
-
-	reg [5:0] reset_cnt = 0;
-	wire resetn = &reset_cnt;
-
-	always @(posedge clk) begin
-		reset_cnt <= reset_cnt + !resetn;
-	end
 
 	wire mem_valid;
 	wire mem_instr;
-	reg mem_ready;
+	wire mem_ready;
 	wire [31:0] mem_addr;
 	wire [31:0] mem_wdata;
 	wire [3:0] mem_wstrb;
-	reg  [31:0] mem_rdata;
+	wire [31:0] mem_rdata;
 
 	wire spimem_ready;
 	wire [31:0] spimem_rdata;
 
+	reg ram_ready;
+	reg [31:0] ram_rdata;
+
+	assign iomem_valid = mem_valid && (mem_addr[31:24] > 8'h 01);
+	assign iomem_wstrb = mem_wstrb;
+	assign iomem_addr = mem_addr;
+	assign iomem_wdata = mem_wdata;
+
+	assign mem_ready = (iomem_valid && iomem_ready) || spimem_ready || ram_ready;
+	assign mem_rdata = (iomem_valid && iomem_ready) ? iomem_rdata : spimem_ready ? spimem_rdata : ram_ready ? ram_rdata : 32'h xxxx_xxxx;
+
 	picorv32 #(
 		.STACKADDR(STACKADDR),
 		.PROGADDR_RESET(PROGADDR_RESET)
 	) cpu (
 		.clk         (clk        ),
 		.resetn      (resetn     ),
-		.trap        (trap       ),
 		.mem_valid   (mem_valid  ),
 		.mem_instr   (mem_instr  ),
-		.mem_ready   (mem_ready  || spimem_ready),
+		.mem_ready   (mem_ready  ),
 		.mem_addr    (mem_addr   ),
 		.mem_wdata   (mem_wdata  ),
 		.mem_wstrb   (mem_wstrb  ),
-		.mem_rdata   (spimem_ready ? spimem_rdata : mem_rdata  )
+		.mem_rdata   (mem_rdata  )
 	);
 
 	spimemio spimemio (
 		.clk(clk),
 		.resetn(resetn),
-		.valid (mem_valid && mem_addr[31:30] == 2'b10),
+		.valid (mem_valid && mem_addr[31:24] == 8'h 01),
 		.ready (spimem_ready),
 		.addr  (mem_addr[23:0]),
 		.rdata (spimem_rdata),
 
 		.flash_csb (flash_csb),
 		.flash_clk (flash_clk),
-		.flash_io0 (flash_io0),
+
-		.flash_io1 (flash_io1),
+		.flash_io0 (flash_io0_do),
-		.flash_io2 (flash_io2),
+		.flash_io1 (flash_io1_di),
-		.flash_io3 (flash_io3)
+		.flash_io2 (flash_io2_di),
+		.flash_io3 (flash_io3_di)
 	);
 
+	assign flash_io0_oe = 1;
+	assign flash_io1_oe = 0;
+	assign flash_io2_oe = 0;
+	assign flash_io3_oe = 0;
+
+	assign flash_io1_do = 0;
+	assign flash_io2_do = 0;
+	assign flash_io3_do = 0;
+
 	reg [31:0] memory [0:MEM_WORDS-1];
 
 	always @(posedge clk) begin
-		mem_ready <= 0;
+		ram_ready <= 0;
-		if (mem_valid && !mem_ready) begin
+		if (mem_valid && !mem_ready && mem_addr[31:24] == 8'h 00) begin
-			if (mem_addr < 4*MEM_WORDS) begin
+			ram_ready <= 1;
-				mem_ready <= 1;
+			ram_rdata <= memory[mem_addr >> 2];
-				mem_rdata <= memory[mem_addr >> 2];
 			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];
 		end
-			if (mem_addr == 32'h c000_0000) begin
-				mem_ready <= 1;
-				mem_rdata <= gpio_i;
-				if (mem_wstrb[0]) gpio_o[ 7: 0] <= mem_wdata[ 7: 0];
-				if (mem_wstrb[1]) gpio_o[15: 8] <= mem_wdata[15: 8];
-				if (mem_wstrb[2]) gpio_o[23:16] <= mem_wdata[23:16];
-				if (mem_wstrb[3]) gpio_o[31:24] <= mem_wdata[31:24];
-			end
-		end
 	end
 endmodule

picosoc/pinout.pcf

@@ -1,83 +0,0 @@
-
-# Pinout for the iCE40-HX8K Breakout Board
-
-set_io clk J3
-
-set_io flash_csb R12
-set_io flash_clk R11
-set_io flash_io0 P12
-set_io flash_io1 P11
-set_io flash_io2 T9  # center on J3
-set_io flash_io3 P8  # center on J3
-
-# All the GPIO pins below are connected to pins that are floating
-# on the iCE40-HX8K Breakout Board, expect the marked LED pins.
-
-set_io trap C3 # LED7
-
-set_io gpio_o[0] C14
-set_io gpio_o[1] D13
-set_io gpio_o[2] C12
-set_io gpio_o[3] E11
-set_io gpio_o[4] C13
-set_io gpio_o[5] E10
-set_io gpio_o[6] C11
-set_io gpio_o[7] D11
-set_io gpio_o[8] C10
-set_io gpio_o[9] D10
-set_io gpio_o[10] L10
-set_io gpio_o[11] E9
-set_io gpio_o[12] B5  # LED0
-set_io gpio_o[13] B4  # LED1
-set_io gpio_o[14] A2  # LED2
-set_io gpio_o[15] A1  # LED3
-set_io gpio_o[16] C5  # LED4
-set_io gpio_o[17] C4  # LED5
-set_io gpio_o[18] B3  # LED6
-set_io gpio_o[19] D9
-set_io gpio_o[20] F9
-set_io gpio_o[21] D8
-set_io gpio_o[22] D7
-set_io gpio_o[23] D6
-set_io gpio_o[24] E6
-set_io gpio_o[25] D5
-set_io gpio_o[26] D4
-set_io gpio_o[27] E5
-set_io gpio_o[28] D3
-set_io gpio_o[29] M13
-set_io gpio_o[30] M14
-set_io gpio_o[31] L12
-
-set_io gpio_i[0] L13
-set_io gpio_i[1] L14
-set_io gpio_i[2] K12
-set_io gpio_i[3] J10
-set_io gpio_i[4] J11
-set_io gpio_i[5] K13
-set_io gpio_i[6] J12
-set_io gpio_i[7] J13
-set_io gpio_i[8] J16
-set_io gpio_i[9] H13
-set_io gpio_i[10] H12
-set_io gpio_i[11] G10
-set_io gpio_i[12] G11
-set_io gpio_i[13] G13
-set_io gpio_i[14] G12
-set_io gpio_i[15] F12
-set_io gpio_i[16] F11
-set_io gpio_i[17] E14
-set_io gpio_i[18] F13
-set_io gpio_i[19] E13
-set_io gpio_i[20] N6
-set_io gpio_i[21] P4
-set_io gpio_i[22] N5
-set_io gpio_i[23] P5
-set_io gpio_i[24] M7
-set_io gpio_i[25] N7
-set_io gpio_i[26] P6
-set_io gpio_i[27] M8
-set_io gpio_i[28] L9
-set_io gpio_i[29] P7
-set_io gpio_i[30] N9
-set_io gpio_i[31] M9
-

picosoc/testbench.v

@@ -18,13 +18,20 @@
  */
 
 module testbench;
-	reg clk = 1;
+	reg clk;
-	always #5 clk = ~clk;
+	always #5 clk = (clk === 1'b0);
+
+	reg resetn = 0;
 
 	initial begin
 		$dumpfile("testbench.vcd");
 		$dumpvars(0, testbench);
+
+		repeat (100) @(posedge clk);
+		resetn <= 1;
+
 		repeat (100000) @(posedge clk);
+
 		$display("");
 		$display("[TIMEOUT]");
 		$stop;
@@ -35,32 +42,92 @@ module testbench;
 
 	wire flash_csb;
 	wire flash_clk;
+
 	wire flash_io0;
 	wire flash_io1;
 	wire flash_io2;
 	wire flash_io3;
 
-	always @(gpio_o) begin
+	wire flash_io0_oe;
-		$write("<GPIO:%02x>", gpio_o[7:0]);
+	wire flash_io1_oe;
-		if (gpio_o == 63) begin
+	wire flash_io2_oe;
+	wire flash_io3_oe;
+
+	wire flash_io0_do;
+	wire flash_io1_do;
+	wire flash_io2_do;
+	wire flash_io3_do;
+
+	wire flash_io0_di = flash_io0;
+	wire flash_io1_di = flash_io1;
+	wire flash_io2_di = flash_io2;
+	wire flash_io3_di = flash_io3;
+
+	assign flash_io0 = flash_io0_oe ? flash_io0_do : 1'bz;
+	assign flash_io1 = flash_io1_oe ? flash_io1_do : 1'bz;
+	assign flash_io2 = flash_io2_oe ? flash_io2_do : 1'bz;
+	assign flash_io3 = flash_io3_oe ? flash_io3_do : 1'bz;
+
+	wire        iomem_valid;
+	reg         iomem_ready;
+	wire [3:0]  iomem_wstrb;
+	wire [31:0] iomem_addr;
+	wire [31:0] iomem_wdata;
+	reg  [31:0] iomem_rdata;
+
+	reg [31:0] gpio;
+
+	always @(posedge clk) begin
+		iomem_ready <= 0;
+		if (iomem_valid && !iomem_ready && iomem_addr[31:24] == 8'h 02) begin
+			iomem_ready <= 1;
+			iomem_rdata <= gpio;
+			if (iomem_wstrb[0]) gpio[ 7: 0] <= iomem_wdata[ 7: 0];
+			if (iomem_wstrb[1]) gpio[15: 8] <= iomem_wdata[15: 8];
+			if (iomem_wstrb[2]) gpio[23:16] <= iomem_wdata[23:16];
+			if (iomem_wstrb[3]) gpio[31:24] <= iomem_wdata[31:24];
+		end
+	end
+
+	always @(gpio) begin
+		$write("<GPIO:%02x>", gpio[7:0]);
+		if (gpio == 63) begin
 			$display("[OK]");
 			$finish;
 		end
-		if (gpio_o % 8 == 7) begin
+		if (gpio % 8 == 7) begin
 			$display("");
 		end
 	end
 
 	picosoc uut (
 		.clk          (clk         ),
-		.gpio_i   (gpio_i   ),
+		.resetn       (resetn      ),
-		.gpio_o   (gpio_o   ),
+
-		.flash_csb(flash_csb),
+		.flash_csb    (flash_csb   ),
-		.flash_clk(flash_clk),
+		.flash_clk    (flash_clk   ),
-		.flash_io0(flash_io0),
+
-		.flash_io1(flash_io1),
+		.flash_io0_oe (flash_io0_oe),
-		.flash_io2(flash_io2),
+		.flash_io1_oe (flash_io1_oe),
-		.flash_io3(flash_io3)
+		.flash_io2_oe (flash_io2_oe),
+		.flash_io3_oe (flash_io3_oe),
+
+		.flash_io0_do (flash_io0_do),
+		.flash_io1_do (flash_io1_do),
+		.flash_io2_do (flash_io2_do),
+		.flash_io3_do (flash_io3_do),
+
+		.flash_io0_di (flash_io0_di),
+		.flash_io1_di (flash_io1_di),
+		.flash_io2_di (flash_io2_di),
+		.flash_io3_di (flash_io3_di),
+
+		.iomem_valid  (iomem_valid ),
+		.iomem_ready  (iomem_ready ),
+		.iomem_wstrb  (iomem_wstrb ),
+		.iomem_addr   (iomem_addr  ),
+		.iomem_wdata  (iomem_wdata ),
+		.iomem_rdata  (iomem_rdata )
 	);
 
 	spiflash spiflash (