[platform][lpc15xx] add script and code to sign lk.bin

LPC wants you to stuff a checksum in the 8th vector slot.

platform/lpc15xx/lpccheck.py

@@ -0,0 +1,23 @@
+#!/usr/bin/env python
+
+import sys, os, struct
+
+if len(sys.argv) < 2:
+    print "not enough args, usage:"
+    print "%s <binfile>" % sys.argv[0]
+    sys.exit(1)
+
+f = open(sys.argv[1], "r+b")
+
+a = struct.unpack('iiiiiii', f.read(7*4))
+
+s = 0
+for i in a:
+    s += i
+s = -s
+
+f.seek(7*4)
+f.write(struct.pack('i', s))
+
+f.close()
+

platform/lpc15xx/rules.mk

@@ -54,4 +54,16 @@ MODULE_DEPS += \
 	platform/lpc15xx/lpcopen \
 	lib/cbuf
 
+LPCSIGNEDBIN := $(OUTBIN).sign
+LPCCHECK := $(LOCAL_DIR)/lpccheck.py
+EXTRA_BUILDDEPS += $(LPCSIGNEDBIN)
+GENERATED += $(LPCSIGNEDBIN)
+
+$(LPCSIGNEDBIN): $(OUTBIN) $(LPCCHECK)
+	@$(MKDIR)
+	$(NOECHO)echo generating $@; \
+	cp $< $@.tmp; \
+	$(LPCCHECK) $@.tmp; \
+	mv $@.tmp $@
+
 include make/module.mk