flash/nor: Add Infineon XMC1000 flash driver

The XMC1000 family uses a very different flash interface from XMC4000.

Tested on XMC 2Go and XMC1100 Boot Kit.

Change-Id: I3edaed420ef1c0fb89fdf221022c8b04163d41b3
Signed-off-by: Andreas Färber <afaerber@suse.de>
Reviewed-on: http://openocd.zylin.com/3418
Reviewed-by: Freddie Chopin <freddie.chopin@gmail.com>
Tested-by: jenkins

contrib/loaders/flash/xmc1xxx/erase.S

@@ -0,0 +1,53 @@
+/*
+ * Infineon XMC1000 flash sectors erase
+ *
+ * Copyright (c) 2016 Andreas Färber
+ *
+ * Based on XMC1100 AA-Step Reference Manual
+ *
+ * License: GPL-2.0+
+ */
+
+#include "xmc1xxx.S"
+
+#define DUMMY_VALUE 0x42
+
+	.macro erase_page, nvmbase, addr, tmp, tmp2
+
+	movs	\tmp, #DUMMY_VALUE
+	str	\tmp, [\addr]
+
+	busy_wait \nvmbase, \tmp, \tmp2
+
+	.endm
+
+
+	.macro erase, nvmbase, addr, end, tmp, tmp2
+
+	movs	\tmp, #NVMPROG_ACTION_PAGE_ERASE_CONTINUOUS
+	strh	\tmp, [\nvmbase, #NVMPROG]
+2001:
+	erase_page \nvmbase, \addr, \tmp, \tmp2
+
+	movs	\tmp, #(NVM_PAGE_SIZE - 1)
+	adds	\tmp, \tmp, #1
+	add	\addr, \addr, \tmp
+	cmp	\addr, \end
+	blt	2001b
+
+	movs	\tmp, #NVMPROG_ACTION_IDLE
+	strh	\tmp, [\nvmbase, #NVMPROG]
+
+	.endm
+
+
+	/*
+	 * r0 = 0x40050000
+	 * r1 = e.g. 0x10001000
+	 * r2 = e.g. 0x10011000
+	 * NVMPROG.ACTION = 0x00
+	 */
+erase:
+	erase r0, r1, r2, r3, r4
+
+	bkpt	#0