[usb-flasher] Create a standalone DFU .bin.

Change-Id: I34e87b66cc51f4e6f4578c8efc7a510ee08cd138

build/targets.device.mak

@@ -43,3 +43,6 @@ products += $(patsubst %.$(EXE),%.map,$(filter %.$(EXE),$(products)))
 .PHONY: openocd
 openocd:
 	openocd -f build/device/openocd.cfg
+
+flasher.$(EXE): LDFLAGS = --gc-sections -T ion/src/device/usb/flasher.ld
+flasher.$(EXE): $(objs) $(usb_objs) ion/src/device/usb/flasher.o

ion/src/device/usb/Makefile

@@ -34,19 +34,19 @@ objs += $(usb_objs)
 
 else
 
-usb_objs += liba/src/assert.o
-usb_objs += liba/src/strlen.o
-usb_objs += liba/src/strlcpy.o
-usb_objs += liba/src/memset.o
-usb_objs += liba/src/memcpy.o
-usb_objs += libaxx/src/cxxabi/pure_virtual.o
-usb_objs += ion/src/device/usb/boot.o
-usb_objs += ion/src/device/keyboard.o
-usb_objs += ion/src/device/device.o
-usb_objs += ion/src/device/usb.o
+dfu_objs += liba/src/assert.o
+dfu_objs += liba/src/strlen.o
+dfu_objs += liba/src/strlcpy.o
+dfu_objs += liba/src/memset.o
+dfu_objs += liba/src/memcpy.o
+dfu_objs += libaxx/src/cxxabi/pure_virtual.o
+dfu_objs += ion/src/device/usb/boot.o
+dfu_objs += ion/src/device/keyboard.o
+dfu_objs += ion/src/device/device.o
+dfu_objs += ion/src/device/usb.o
 
-ion/src/device/usb/dfu.elf: LDFLAGS = --gc-sections -T ion/src/device/boot/dfu.ld
-ion/src/device/usb/dfu.elf: $(usb_objs)
+ion/src/device/usb/dfu.elf: LDFLAGS = --gc-sections -T ion/src/device/usb/dfu.ld
+ion/src/device/usb/dfu.elf: $(usb_objs) $(dfu_objs)
 
 ion/src/device/usb/dfu.o: ion/src/device/usb/dfu.bin
 	@echo "OBJCOPY $@"

ion/src/device/usb/flasher.cpp

@@ -0,0 +1,8 @@
+#include "../regs/regs.h"
+#include "../usb/calculator.h"
+
+void ion_main(int argc, char * argv[]) {
+  while (!OTG.GINTSTS()->getENUMDNE()) {
+  }
+  Ion::USB::Device::Calculator::Poll();
+}

ion/src/device/usb/flasher.ld

@@ -0,0 +1,68 @@
+/* Create a flash bridge.
+ * Load it at address 0x20004000 and execute it from there
+ * TODO: Explain the 16K offset (ST's DFU ROMed bootloader)
+ */
+
+MEMORY {
+  RAM_BUFFER (rw) : ORIGIN = 0x20000000 + 16K, LENGTH = 256K - 16K
+}
+
+STACK_SIZE = 4K;
+
+SECTIONS {
+  .isr_vector_table ORIGIN(RAM_BUFFER) : {
+    KEEP(*(.isr_vector_table))
+  } >RAM_BUFFER
+
+  .text : {
+    . = ALIGN(4);
+    *(.text)
+    *(.text.*)
+  } >RAM_BUFFER
+
+  .init_array : {
+    . = ALIGN(4);
+    _init_array_start = .;
+    KEEP (*(.init_array*))
+    _init_array_end = .;
+  } >RAM_BUFFER
+
+  .rodata : {
+    . = ALIGN(4);
+    *(.rodata)
+    *(.rodata.*)
+  } >RAM_BUFFER
+
+  .data : {
+    . = ALIGN(4);
+    *(.data)
+    *(.data.*)
+  } >RAM_BUFFER
+
+  .bss : {
+    . = ALIGN(4);
+    _bss_section_start_ram = .;
+    *(.bss)
+    *(.bss.*)
+    *(COMMON)
+    _bss_section_end_ram = .;
+  } >RAM_BUFFER
+
+  .stack : {
+    . = ALIGN(8);
+    _stack_end = .;
+    . += (STACK_SIZE - 8);
+    . = ALIGN(8);
+    _stack_start = .;
+  } >RAM_BUFFER
+
+  .phony : {
+    /* We won't do dynamic memory allocation */
+    _heap_start = .;
+    _heap_end = .;
+    /* Effectively bypass copying .data to RAM */
+    _data_section_start_flash = .;
+    _data_section_start_ram = .;
+    _data_section_end_ram = .;
+  } >RAM_BUFFER
+}