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-rw-r--r--bootrom/bram.mk79
-rw-r--r--bootrom/common/bram.ld40
-rw-r--r--bootrom/common/mem.awk63
-rw-r--r--bootrom/demo/Makefile5
-rw-r--r--bootrom/demo/demo.S71
-rw-r--r--bootrom/demo/hello_msg.txt37
6 files changed, 295 insertions, 0 deletions
diff --git a/bootrom/bram.mk b/bootrom/bram.mk
new file mode 100644
index 0000000..2c7875a
--- /dev/null
+++ b/bootrom/bram.mk
@@ -0,0 +1,79 @@
+ifndef _BRAM_MK
+_BRAM_MK := # defined
+
+BRAM_ADDR := 0x1000
+
+BASEDIR := $(dir $(lastword $(MAKEFILE_LIST)))
+BASEDIR := $(BASEDIR:/=)
+DATADIR := $(BASEDIR)/common
+
+LDSCRIPT := $(DATADIR)/bram.ld
+MEMSCRIPT := $(DATADIR)/mem.awk
+
+BITFILEDIR := $(BASEDIR)/../bitfile
+BITFILE_VERSION ?= 0-1
+
+BITFILE := $(BITFILEDIR)/freedom-e300-arty-$(BITFILE_VERSION).bit
+CFGFILE := $(BITFILEDIR)/FreedomE-$(BITFILE_VERSION).cfg
+MEMINFO := $(BITFILEDIR)/freedom-e300-arty-$(BITFILE_VERSION).mmi
+BRAM_INST := `cat $(BITFILEDIR)/freedom-e300-arty-$(BITFILE_VERSION)-bootrom.txt`
+
+XLEN = 32
+BRAM_WIDTH=64
+
+all: mcs
+
+$(BITFILE):
+ @echo "In order to get Version $(BITFILE_VERSION) of the bitfile:"
+ @echo ""
+ @cat $(BITFILEDIR)/README.md
+
+CC := ../../toolchain/bin/riscv$(XLEN)-unknown-elf-gcc
+UPDATEMEM ?= updatemem
+
+CDEFINES += -DCFG_STRING=\"$(CFGFILE)\"
+
+CFLAGS ?= -m$(XLEN) -O2 -std=c11 -pedantic -Wall \
+ -nostartfiles -fno-common -mcmodel=medany -g \
+ $(CDEFINES)
+
+LDFLAGS ?= -T$(LDSCRIPT) -static -nostdlib
+OBJCOPY ?= objcopy
+elf: $(PROG).elf
+hex: $(PROG).hex
+mem: $(PROG).impl.mem
+mcs: $(PROG).mcs
+
+$(PROG).elf: $(SRCS) $(EXTRAS) $(CFGFILE)
+ $(CC) $(CFLAGS) $(LDFLAGS) -o $@ $(SRCS)
+
+$(PROG).hex: $(PROG).elf
+ $(OBJCOPY) -S -O verilog --change-addresses -$(BRAM_ADDR) $< $@
+
+# Manually reverse the byte order due to limitations in UpdateMEM.
+# Per UG898: "When UpdateMEM inputs data, it takes data from data input
+# files in Bit Lane sized chunks from the most right value first to the
+# left most. For example, if the first 64 bits of input data are
+# 0xB47DDE02826A8419 then the value 0xB4 is the first value to be set
+# into a Block RAM."
+$(PROG).impl.mem: $(PROG).hex $(MEMSCRIPT)
+ awk -v WIDTH=$(BRAM_WIDTH) -v REVERSE=1 -f $(MEMSCRIPT) $< > $@
+
+.PHONY: $(PROG).mcs
+$(PROG).mcs : $(BITFILE) $(PROG).impl.mem
+ @echo ""
+ @echo ""
+ @echo "TO COMPLETE THE BUILD OF $(PROG).mcs, "
+ @echo "ENTER THE FOLLOWING IN THE VIVADO TCL WINDOW:"
+ @echo ""
+ @echo "cd `pwd`"
+ @echo ""
+ @echo "exec $(UPDATEMEM) -meminfo $(MEMINFO) -data $(PROG).impl.mem -proc $(BRAM_INST) -bit $(BITFILE) --out $(PROG).bit -force"
+ @echo ""
+ @echo "write_cfgmem -format mcs -interface spix4 -size 16 -loadbit {up 0x0 $(PROG).bit} -file $(PROG).mcs -force"
+ @echo ""
+
+clean:
+ rm -f -- $(foreach ext,elf hex impl.mem bit mcs,$(PROG).$(ext))
+
+endif # _BRAM_MK
diff --git a/bootrom/common/bram.ld b/bootrom/common/bram.ld
new file mode 100644
index 0000000..45df67f
--- /dev/null
+++ b/bootrom/common/bram.ld
@@ -0,0 +1,40 @@
+OUTPUT_ARCH("riscv")
+ENTRY(_start)
+
+MEMORY
+{
+ rom (rx) : ORIGIN = 0x00001000, LENGTH = 4K
+ ram (rwx) : ORIGIN = 0x80000000, LENGTH = 256M
+}
+
+SECTIONS
+{
+ PROVIDE(_rom = ORIGIN(rom));
+ PROVIDE(_rom_end = _rom + LENGTH(rom));
+ PROVIDE(_ram = ORIGIN(ram));
+ PROVIDE(_ram_end = _ram + LENGTH(ram));
+
+ .text : {
+ PROVIDE(_ftext = .);
+ *(.text.init)
+ *(.text .text.* .gnu.linkonce.t.*)
+ PROVIDE(_etext = .);
+ } > rom
+
+ .rodata : {
+ *(.rodata .rodata.* .gnu.linkonce.r.*)
+ } > rom
+
+ .bss : ALIGN(8) {
+ PROVIDE(_fbss = .);
+ *(.bss .bss.* .gnu.linkonce.b.*)
+ *(.sbss .sbss.* .gnu.linkonce.sb.*)
+ . = ALIGN(8);
+ PROVIDE(_ebss = .);
+ } > ram
+
+ . += 0x1000;
+ PROVIDE(_sp = NEXT(0x1000));
+
+ PROVIDE(_end = .);
+}
diff --git a/bootrom/common/mem.awk b/bootrom/common/mem.awk
new file mode 100644
index 0000000..3003b56
--- /dev/null
+++ b/bootrom/common/mem.awk
@@ -0,0 +1,63 @@
+BEGIN {
+ RS = ORS = "\r\n"
+ addr = 0
+ buf = ""
+ limit = (WIDTH > 0 ? WIDTH / 4 : 16)
+ print "@00000000"
+}
+
+# Portable strtonum() replacement
+function atoi(str, x, n, i, b, c) {
+ if (str ~ /^0[0-7]*$/) {
+ i = 2
+ b = 8
+ } else if (str ~ /^0[xX][[:xdigit:]]+$/) {
+ i = 3
+ b = 16
+ } else {
+ return str
+ }
+
+ x = 0
+ n = length(str)
+ for (; i <= n; i++) {
+ c = tolower(substr(str, i , 1))
+ c = index("123456789abcdef", c)
+ x = (x * b) + c
+ }
+ return x
+}
+
+function out(x) {
+ addr++
+ buf = (REVERSE ? buf x : x buf)
+ if (length(buf) >= limit) {
+ print buf
+ buf = ""
+ }
+}
+
+function pad(n) {
+ while (addr < n) {
+ out("00")
+ }
+}
+
+match($1, /^@[[:xdigit:]]+/) {
+ pad(atoi("0x" substr($1, RSTART+1, RLENGTH-1)))
+ next
+}
+
+{
+ for (i = 1; i <= NF; i++) {
+ out($i)
+ }
+}
+
+END {
+ align = limit / 2
+ pad(int((addr + align - 1) / align) * align)
+ if (length(buf) > 0) {
+ print buf;
+ }
+}
diff --git a/bootrom/demo/Makefile b/bootrom/demo/Makefile
new file mode 100644
index 0000000..dfe3663
--- /dev/null
+++ b/bootrom/demo/Makefile
@@ -0,0 +1,5 @@
+PROG := demo
+SRCS := demo.S
+EXTRAS := hello_msg.txt
+
+include ../bram.mk
diff --git a/bootrom/demo/demo.S b/bootrom/demo/demo.S
new file mode 100644
index 0000000..c6f2618
--- /dev/null
+++ b/bootrom/demo/demo.S
@@ -0,0 +1,71 @@
+#define UART_BASE 0x48000000
+#define SPI_BASE 0x48001000
+#define GPIO_BASE 0x48002000
+
+#ifndef CFG_STRING
+#error Must define CFG_STRING
+#endif
+
+ .globl _start
+_start:
+ j uart_init
+ nop
+ nop
+ .word cfgstr
+
+uart_init:
+ // a1 = UART_TX
+ // a2 = hello_msg_end
+ // for (a0 = hello_msg_start; a0 != a2; ++ a0){
+ // while (a3 = TX_READY == 0);
+ // a3 = *a0
+ // *a1 = a3
+ // }
+
+ la a0, hello_msg_start
+ la a2, hello_msg_end
+ li a1, UART_BASE
+
+uart_loop:
+ lw a3, 4(a1) // Wait until non-zero (uart can send data).
+ beqz a3, uart_loop
+
+ lb a3, 0(a0) // read the next character in hello_msg
+ sw a3, 0(a1) // Write the current character.
+ addi a0, a0, 1 // increment the pointer.
+ bne a0, a2, uart_loop
+
+gpio_init:
+ li a0, GPIO_BASE
+ li t0, 0xFFFF0000
+ sw t0, 4(a0)
+
+gpio_loop:
+ // For Red LEDs, increment manually.
+ li t0, 0x1
+ sw t0, (a0)
+ li t0, 0x2
+ sw t0, (a0)
+ li t0, 0x4
+ sw t0, (a0)
+ li t0, 0x8
+ sw t0, (a0)
+
+ // For Blue and Green LEDs, sample the switches & buttons
+
+ lw t0, (a0)
+ srli t0, t0, 16
+ andi t0, t0, 0xFF
+ slli t0, t0, 4
+ sw t0, (a0)
+
+ j gpio_loop
+
+ .section .rodata
+
+hello_msg_start:
+ .incbin "hello_msg.txt"
+hello_msg_end:
+
+cfgstr:
+ .incbin CFG_STRING
diff --git a/bootrom/demo/hello_msg.txt b/bootrom/demo/hello_msg.txt
new file mode 100644
index 0000000..c3cb3f2
--- /dev/null
+++ b/bootrom/demo/hello_msg.txt
@@ -0,0 +1,37 @@
+
+ SIFIVE, INC.
+
+ 5555555555555555555555555
+ 5555 5555
+ 5555 5555
+ 5555 5555
+ 5555 5555555555555555555555
+ 5555 555555555555555555555555
+ 5555 5555
+ 5555 5555
+ 5555 5555
+5555555555555555555555555555 55555
+ 55555 555555555 55555
+ 55555 55555 55555
+ 55555 5 55555
+ 55555 55555
+ 55555 55555
+ 55555 55555
+ 55555 55555
+ 55555 55555
+ 555555555
+ 55555
+ 5
+
+ SiFive RISC-V Coreplex
+
+Welcome to the Arty FPGA Freedom E Dev Kit.
+The red LEDs are blinking very fast and appear
+dim. Try pressing the buttons and switches to control
+the blue and green LEDs. You can try using the
+debugger to step through the boot code.
+
+
+
+
+
generated by cgit v1.2.3 (git 2.25.1) at 2025-10-31 11:12:06 +0000