xmc4xxx: Integrate build of erase check code

Instead of pointing to the assembler sources in a comment and
inline-commenting the THUMB bytecode, place the hex array alongside the
assembler sources and include it via preprocessor.

Originally inspired by a typo in the file path during driver development,
but it also facilitates making changes to the assembler sources.

A Makefile is provided to help automate updating the bytecode. It is not
integrated with the automake system to avoid forcing an ARM cross-compiler
onto every user, i.e. after modifying the sources they need to be rebuilt
in that directory before building the usual way. ARM_CROSS_COMPILE= can
be passed on the make command line to deal with native ARM toolchains
or with varying prefixes of cross-toolchains.

Change-Id: I00ceb980a68c8554a180dd13719ac77b677a8bcd
Signed-off-by: Andreas Färber <afaerber@suse.de>
Reviewed-on: http://openocd.zylin.com/3133
Tested-by: jenkins
Reviewed-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>
Reviewed-by: Paul Fertser <fercerpav@gmail.com>

contrib/loaders/erase_check/Makefile

@@ -0,0 +1,19 @@
+BIN2C = ../../../src/helper/bin2char.sh
+
+ARM_CROSS_COMPILE ?= arm-none-eabi-
+ARM_AS      ?= $(ARM_CROSS_COMPILE)as
+ARM_OBJCOPY ?= $(ARM_CROSS_COMPILE)objcopy
+
+arm: armv7m_erase_check.inc armv7m_0_erase_check.inc
+
+armv7m_%.elf: armv7m_%.s
+	$(ARM_AS) $< -o $@
+
+armv7m_%.bin: armv7m_%.elf
+	$(ARM_OBJCOPY) -Obinary $< $@
+
+armv7m_%.inc: armv7m_%.bin
+	$(BIN2C) < $< > $@
+
+clean:
+	-rm -f *.elf *.bin *.inc

contrib/loaders/erase_check/armv7m_0_erase_check.inc

@@ -0,0 +1,2 @@
+/* Autogenerated with ../../../src/helper/bin2char.sh */
+0x03,0x78,0x01,0x30,0x1a,0x43,0x01,0x39,0xfa,0xd1,0x00,0xbe,

src/flash/nor/xmc4xxx.c

@@ -628,16 +628,8 @@ int xmc4xxx_blank_check_memory(struct target *target,
 	struct armv7m_algorithm armv7m_info;
 	int retval;
 
-	/* see contrib/loaders/erase_check/armv7m_0_erase_check.s for src */
-
 	static const uint8_t erase_check_code[] = {
-		/* loop: */
-		0x03, 0x78,		/* ldrb	r3, [r0] */
-		0x01, 0x30,		/* adds	r0, #1 */
-		0x1A, 0x43,		/* orrs	r2, r2, r3 */
-		0x01, 0x39,		/* subs	r1, r1, #1 */
-		0xFA, 0xD1,		/* bne	loop */
-		0x00, 0xBE		/* bkpt	#0 */
+#include "../../../contrib/loaders/erase_check/armv7m_0_erase_check.inc"
 	};
 
 	/* make sure we have a working area */