ar100: Support for ar100 (#6054)

Add files to support AR100

Signed-off-by: Elias Bakken <elias@iagent.no>

src/ar100/Makefile

@@ -0,0 +1,45 @@
+CROSS_PREFIX=or1k-linux-musl-
+dirs-y += src/generic src/ar100 lib/ar100
+
+CFLAGS		+= -O3
+CFLAGS		+= -fno-builtin
+CFLAGS		+= -fno-pie
+CFLAGS		+= -ffreestanding
+CFLAGS		+= -msfimm -mshftimm -msoft-div -msoft-mul
+CFLAGS		+= -Ilib/ar100
+CFLAGS_klipper.elf := $(CFLAGS) -T src/ar100/ar100.ld
+CFLAGS_klipper.elf += -Wl,--gc-sections -static
+CFLAGS_klipper.elf += -Wl,--no-dynamic-linker
+
+SFLAGS		 = -nostdinc -MMD
+SFLAGS		+= -Ilib/ar100
+
+# Add source files
+src-y += ar100/main.c ar100/gpio.c ar100/serial.c
+src-y += ar100/util.c ar100/timer.c
+src-y += generic/crc16_ccitt.c generic/timer_irq.c
+
+# Remove files that are not needed to save space
+src-y := $(filter-out lcd_hd44780.c,$(src-y))
+src-y := $(filter-out lcd_st7920.c,$(src-y))
+src-y := $(filter-out sensor_angle.c,$(src-y))
+src-y := $(filter-out thermocouple.c,$(src-y))
+
+OBJS_klipper.elf += $(OUT)lib/ar100/start.o
+OBJS_klipper.elf += $(OUT)lib/ar100/runtime.o
+
+# Build the AR100 binary
+target-y += $(OUT)ar100.bin
+
+$(OUT)lib/ar100/start.o:
+	@echo "  Compiling $@"
+	$(Q)$(CC) $(SFLAGS) -c $(PWD)/lib/ar100/start.S -o $@
+
+$(OUT)lib/ar100/runtime.o:
+	@echo "  Compiling $@"
+	$(Q)$(CC) $(SFLAGS) -c $(PWD)/lib/ar100/runtime.S -o $@
+
+$(OUT)ar100.bin: $(OUT)klipper.elf
+	@echo "  Object copy $@"
+	$(OBJCOPY) -O binary -S --reverse-bytes 4 $(OUT)klipper.elf $@
+	truncate -s %8 $@