Merge pull request #94 from hutch31/master

Added new testbench and linker file for ROM load

9 files changed, 469 insertions, 0 deletions

diff --git a/scripts/romload/.gitignore b/scripts/romload/.gitignore
new file mode 100644
index 0000000..6f1295b
--- /dev/null
+++ b/scripts/romload/.gitignore
@@ -0,0 +1,11 @@
+firmware.d
+firmware.elf
+firmware.hex
+firmware32.hex
+firmware.o
+firmware_addr.txt
+firmware_dbg.v
+syscalls.o
+testbench.vvp
+testbench.vcd
+start.elf
diff --git a/scripts/romload/Makefile b/scripts/romload/Makefile
new file mode 100644
index 0000000..d510fa8
--- /dev/null
+++ b/scripts/romload/Makefile
@@ -0,0 +1,41 @@
+ifndef RISCV_TOOLS_PREFIX
+RISCV_TOOLS_PREFIX = /opt/riscv32ic/bin/riscv32-unknown-elf-
+endif
+CXX = $(RISCV_TOOLS_PREFIX)g++ -march=rv32i
+CC = $(RISCV_TOOLS_PREFIX)gcc -march=rv32i
+AS = $(RISCV_TOOLS_PREFIX)gcc -march=rv32i
+CXXFLAGS = -MD -Os -Wall -std=c++11
+CCFLAGS = -MD -Os -Wall
+#LDFLAGS = -Wl,--gc-sections,--no-relax
+LDFLAGS = -Wl,--gc-sections
+LDLIBS =
+
+test: testbench.vvp firmware32.hex
+	vvp -l testbench.log -N testbench.vvp
+
+testbench.vvp: testbench.v ../../picorv32.v firmware_dbg.v
+	iverilog -o testbench.vvp testbench.v ../../picorv32.v
+	chmod -x testbench.vvp
+
+firmware32.hex: firmware.elf hex8tohex32.py
+	$(RISCV_TOOLS_PREFIX)objcopy -O verilog firmware.elf firmware.tmp
+	python3 hex8tohex32.py firmware.tmp > firmware32.hex
+
+
+firmware_dbg.v: firmware.map
+	python3 map2debug.py
+
+start.o: start.S
+	$(CC) -c -nostdlib start.S $(LDLIBS)
+
+firmware.elf: firmware.o syscalls.o start.o
+	$(CC) $(LDFLAGS),-Map=firmware.map -o $@ $^ -T sections.ld $(LDLIBS)
+	chmod -x firmware.elf
+
+clean:
+	rm -f *.o *.d *.tmp start.elf
+	rm -f firmware.elf firmware.hex firmware32.hex
+	rm -f testbench.vvp testbench.vcd
+
+-include *.d
+.PHONY: test clean
diff --git a/scripts/romload/firmware.c b/scripts/romload/firmware.c
new file mode 100644
index 0000000..72bb9a1
--- /dev/null
+++ b/scripts/romload/firmware.c
@@ -0,0 +1,21 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int x1 = 1000;
+int x2 = 2000;
+
+void main() 
+{
+  int z;
+  x1 = 50;
+  x2 = 50;
+
+  printf("hello\n");
+  z = (x1 + x2);
+  if (z == 100)
+    printf("TEST PASSED\n");
+  else
+    printf("TEST FAILED, z=%d\n", z);
+  exit(0);
+}
+
diff --git a/scripts/romload/hex8tohex32.py b/scripts/romload/hex8tohex32.py
new file mode 100644
index 0000000..ae44101
--- /dev/null
+++ b/scripts/romload/hex8tohex32.py
@@ -0,0 +1,34 @@
+#!/usr/bin/env python3
+
+import fileinput
+import itertools
+
+ptr = 0
+data = []
+
+def write_data():
+    if len(data) != 0:
+        print("@%08x" % (ptr >> 2))
+        while len(data) % 4 != 0:
+            data.append(0)
+        for word_bytes in zip(*([iter(data)]*4)):
+            print("".join(["%02x" % b for b in reversed(word_bytes)]))
+
+for line in fileinput.input():
+    if line.startswith("@"):
+        addr = int(line[1:], 16)
+        if addr > ptr+4:
+            write_data()
+            ptr = addr
+            data = []
+            while ptr % 4 != 0:
+                data.append(0)
+                ptr -= 1
+        else:
+            while ptr + len(data) < addr:
+                data.append(0)
+    else:
+        data += [int(tok, 16) for tok in line.split()]
+
+write_data()
+
diff --git a/scripts/romload/map2debug.py b/scripts/romload/map2debug.py
new file mode 100644
index 0000000..fc5c97c
--- /dev/null
+++ b/scripts/romload/map2debug.py
@@ -0,0 +1,30 @@
+#!/usr/bin/env python3
+
+import re
+
+symbol = re.compile("\s*0x([0-9a-f]+)\s+([\w_]+)")
+symbol_map = {}
+with open("firmware.map", "r") as fh:
+    for fd in fh:
+        sym = symbol.match(fd)
+        if (sym):
+            addr = int(sym.group(1), 16)
+            symbol_map[addr] = sym.group(2)
+
+with open("firmware_dbg.v", "w") as fh:
+    for k, v in symbol_map.items():
+        fh.write("`define C_SYM_{1:s} 32'h{0:08x}\n".format(k, v.upper()))
+    fh.write("  task firmware_dbg;\n")
+    fh.write("  input [31:0] addr;\n");
+    fh.write("  begin\n");
+    fh.write("    case (addr)\n");
+    for k, v in symbol_map.items():
+        fh.write("      32'h{0:08x} : $display(\"%t: FCALL: {1:s}\", $time);\n".format(k, v))
+    fh.write("    endcase\n");
+    fh.write("  end\n");
+    fh.write("  endtask\n");
+
+with open("firmware_addr.txt", "w") as fh:
+    for k, v in symbol_map.items():
+        fh.write("{0:08x} {1:s}\n".format(k,v))
+
diff --git a/scripts/romload/sections.ld b/scripts/romload/sections.ld
new file mode 100644
index 0000000..2ec3954
--- /dev/null
+++ b/scripts/romload/sections.ld
@@ -0,0 +1,45 @@
+/*
+This is free and unencumbered software released into the public domain.
+
+Anyone is free to copy, modify, publish, use, compile, sell, or
+distribute this software, either in source code form or as a compiled
+binary, for any purpose, commercial or non-commercial, and by any
+means.
+*/
+
+/* starting address needs to be > 0 due to known bug in RISCV/GNU linker */
+MEMORY {
+	rom(rwx) : ORIGIN = 0x00000100, LENGTH = 63k
+        ram(rwx) : ORIGIN = 0x00020000, LENGTH = 16k
+}
+
+ENTRY(_pvstart);
+
+SECTIONS {
+	.rom : {
+                _pvstart*(.text);
+		start*(.text);
+                . = 0x100;
+                . = ALIGN(4);
+		*(.text);
+        } > rom
+
+        .data : {
+          _data_lma = LOADADDR(.data);
+          _data = .;
+          __global_pointer$ = . ;
+          *(.data .data.* )
+          *(.sdata .sdata.*)
+           . = ALIGN(4);
+          _edata = .;
+        } >ram AT>rom
+
+        .bss : {
+          _bss_start = .;
+          *(.bss .bss.*)
+           . = ALIGN(4);
+          _bss_end = .;
+          _end = .;
+        } >ram
+
+}
diff --git a/scripts/romload/start.S b/scripts/romload/start.S
new file mode 100644
index 0000000..be59808
--- /dev/null
+++ b/scripts/romload/start.S
@@ -0,0 +1,52 @@
+.section .text
+.global _start
+.global _pvstart
+
+_pvstart:
+/* zero-initialize all registers */
+addi x1, zero, 0
+addi x2, zero, 0
+addi x3, zero, 0
+addi x4, zero, 0
+addi x5, zero, 0
+addi x6, zero, 0
+addi x7, zero, 0
+addi x8, zero, 0
+addi x9, zero, 0
+addi x10, zero, 0
+addi x11, zero, 0
+addi x12, zero, 0
+addi x13, zero, 0
+addi x14, zero, 0
+addi x15, zero, 0
+addi x16, zero, 0
+addi x17, zero, 0
+addi x18, zero, 0
+addi x19, zero, 0
+addi x20, zero, 0
+addi x21, zero, 0
+addi x22, zero, 0
+addi x23, zero, 0
+addi x24, zero, 0
+addi x25, zero, 0
+addi x26, zero, 0
+addi x27, zero, 0
+addi x28, zero, 0
+addi x29, zero, 0
+addi x30, zero, 0
+addi x31, zero, 0
+
+/* set stack pointer */
+
+lui sp, %hi(4*1024*1024)
+addi sp, sp, %lo(4*1024*1024)
+
+/* push zeros on the stack for argc and argv */
+/* (stack is aligned to 16 bytes in riscv calling convention) */
+addi sp,sp,-16
+sw zero,0(sp)
+sw zero,4(sp)
+sw zero,8(sp)
+sw zero,12(sp)
+
+j _start
diff --git a/scripts/romload/syscalls.c b/scripts/romload/syscalls.c
new file mode 100644
index 0000000..82e633b
--- /dev/null
+++ b/scripts/romload/syscalls.c
@@ -0,0 +1,95 @@
+// An extremely minimalist syscalls.c for newlib
+// Based on riscv newlib libgloss/riscv/sys_*.c
+// Written by Clifford Wolf.
+
+#include <sys/stat.h>
+#include <unistd.h>
+#include <errno.h>
+
+#define UNIMPL_FUNC(_f) ".globl " #_f "\n.type " #_f ", @function\n" #_f ":\n"
+
+asm (
+	".text\n"
+	".align 2\n"
+	UNIMPL_FUNC(_open)
+	UNIMPL_FUNC(_openat)
+	UNIMPL_FUNC(_lseek)
+	UNIMPL_FUNC(_stat)
+	UNIMPL_FUNC(_lstat)
+	UNIMPL_FUNC(_fstatat)
+	UNIMPL_FUNC(_isatty)
+	UNIMPL_FUNC(_access)
+	UNIMPL_FUNC(_faccessat)
+	UNIMPL_FUNC(_link)
+	UNIMPL_FUNC(_unlink)
+	UNIMPL_FUNC(_execve)
+	UNIMPL_FUNC(_getpid)
+	UNIMPL_FUNC(_fork)
+	UNIMPL_FUNC(_kill)
+	UNIMPL_FUNC(_wait)
+	UNIMPL_FUNC(_times)
+	UNIMPL_FUNC(_gettimeofday)
+	UNIMPL_FUNC(_ftime)
+	UNIMPL_FUNC(_utime)
+	UNIMPL_FUNC(_chown)
+	UNIMPL_FUNC(_chmod)
+	UNIMPL_FUNC(_chdir)
+	UNIMPL_FUNC(_getcwd)
+	UNIMPL_FUNC(_sysconf)
+	"j unimplemented_syscall\n"
+);
+
+void unimplemented_syscall()
+{
+	const char *p = "Unimplemented system call called!\n";
+	while (*p)
+		*(volatile int*)0x10000000 = *(p++);
+	asm volatile ("ebreak");
+	__builtin_unreachable();
+}
+
+ssize_t _read(int file, void *ptr, size_t len)
+{
+	// always EOF
+	return 0;
+}
+
+ssize_t _write(int file, const void *ptr, size_t len)
+{
+	const void *eptr = ptr + len;
+	while (ptr != eptr)
+		*(volatile int*)0x10000000 = *(char*)(ptr++);
+	return len;
+}
+
+int _close(int file)
+{
+	// close is called before _exit()
+	return 0;
+}
+
+int _fstat(int file, struct stat *st)
+{
+	// fstat is called during libc startup
+	errno = ENOENT;
+	return -1;
+}
+
+void *_sbrk(ptrdiff_t incr)
+{
+	extern unsigned char _end[];	// Defined by linker
+	static unsigned long heap_end;
+
+	if (heap_end == 0)
+		heap_end = (long)_end;
+
+	heap_end += incr;
+	return (void *)(heap_end - incr);
+}
+
+void _exit(int exit_status)
+{
+	asm volatile ("ebreak");
+	__builtin_unreachable();
+}
+
diff --git a/scripts/romload/testbench.v b/scripts/romload/testbench.v
new file mode 100644
index 0000000..e38819d
--- /dev/null
+++ b/scripts/romload/testbench.v
@@ -0,0 +1,140 @@
+`timescale 1 ns / 1 ps
+`undef VERBOSE_MEM
+//`undef WRITE_VCD
+`undef MEM8BIT
+
+// define the size of our ROM
+// simulates ROM by suppressing writes below this address
+`define ROM_SIZE 32'h0001_00FF
+
+module testbench;
+	reg clk = 1;
+	reg resetn = 0;
+	wire trap;
+
+	always #5 clk = ~clk;
+
+	initial begin
+		repeat (100) @(posedge clk);
+		resetn <= 1;
+	end
+
+	wire mem_valid;
+	wire mem_instr;
+	reg mem_ready;
+	wire [31:0] mem_addr;
+	wire [31:0] mem_wdata;
+	wire [3:0] mem_wstrb;
+	reg  [31:0] mem_rdata;
+
+`include "firmware_dbg.v"
+
+	picorv32 #(
+		.COMPRESSED_ISA(1),
+		.PROGADDR_RESET(32'h100)
+	) 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  )
+	);
+
+	localparam MEM_SIZE = 4*1024*1024;
+`ifdef MEM8BIT
+	reg [7:0] memory [0:MEM_SIZE-1];
+	initial 
+		$readmemh("firmware.hex", memory);
+	end
+`else
+	reg [31:0] memory [0:MEM_SIZE/4-1];
+	integer x;
+
+	// simulate hardware assist of clearing RAM and copying ROM data into
+	// memory
+	initial
+	begin
+		// clear memory
+		for (x=0; x<MEM_SIZE/4; x=x+1) memory[x] = 0;
+		// load rom contents
+		$readmemh("firmware32.hex", memory);
+		// copy .data section
+		for (x=0; x<(`C_SYM__BSS_START - `C_SYM___GLOBAL_POINTER); x=x+4)
+			memory[(`C_SYM___GLOBAL_POINTER+x)/4] = memory[(`C_SYM__DATA_LMA+x)/4];
+	end
+`endif
+
+	always @(posedge clk) begin
+		mem_ready <= 0;
+		if (mem_valid && !mem_ready) begin
+			mem_ready <= 1;
+			mem_rdata <= 'bx;
+			case (1)
+				mem_addr < MEM_SIZE: begin
+`ifdef MEM8BIT
+					if (|mem_wstrb) begin
+						if (mem_wstrb[0]) memory[mem_addr + 0] <= mem_wdata[ 7: 0];
+						if (mem_wstrb[1]) memory[mem_addr + 1] <= mem_wdata[15: 8];
+						if (mem_wstrb[2]) memory[mem_addr + 2] <= mem_wdata[23:16];
+						if (mem_wstrb[3]) memory[mem_addr + 3] <= mem_wdata[31:24];
+					end else begin
+						mem_rdata <= {memory[mem_addr+3], memory[mem_addr+2], memory[mem_addr+1], memory[mem_addr]};
+					end
+`else
+					if ((|mem_wstrb) && (mem_addr >= `ROM_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];
+					end else begin
+						mem_rdata <= memory[mem_addr >> 2];
+					end
+`endif
+				end
+				mem_addr == 32'h 1000_0000: begin
+					$write("%c", mem_wdata[7:0]);
+				end
+			endcase
+		end
+		if (mem_valid && mem_ready) begin
+`ifdef FIRMWARE_DEBUG_ADDR
+			firmware_dbg(mem_addr);
+`endif
+			if ((mem_wstrb == 4'h0) && (mem_rdata === 32'bx)) $display("READ FROM UNITIALIZED ADDR=%x", mem_addr);
+`ifdef VERBOSE_MEM
+			if (|mem_wstrb)
+				$display("WR: ADDR=%x DATA=%x MASK=%b", mem_addr, mem_wdata, mem_wstrb);
+			else
+				$display("RD: ADDR=%x DATA=%x%s", mem_addr, mem_rdata, mem_instr ? " INSN" : "");
+`endif
+			if (^mem_addr === 1'bx ||
+					(mem_wstrb[0] && ^mem_wdata[ 7: 0] == 1'bx) ||
+					(mem_wstrb[1] && ^mem_wdata[15: 8] == 1'bx) ||
+					(mem_wstrb[2] && ^mem_wdata[23:16] == 1'bx) ||
+					(mem_wstrb[3] && ^mem_wdata[31:24] == 1'bx)) begin
+				$display("CRITICAL UNDEF MEM TRANSACTION");
+				$finish;
+			end
+		end
+	end
+
+`ifdef WRITE_VCD
+	initial begin
+		$dumpfile("testbench.vcd");
+		$dumpvars(0, testbench);
+	end
+`endif
+
+	always @(posedge clk) begin
+		if (resetn && trap) begin
+			repeat (10) @(posedge clk);
+			$display("TRAP");
+			$finish;
+		end
+	end
+endmodule