[PATCH v2 4/5] ARM: zynq: add zynq fsbl checksum script

[Steffen Trumtrar]

The bootrom only reads an image if the correct checksum is present in the
header. The calculation is pretty simple:
sum over all words from 0x20 to 0x44
Two of this words are the image length. That is why the checksum can not be
calculated until barebox_image_size is known.
The easiest solution is a program that has to be run after make.
Maybe this can be replaced with some linker-fu.

Signed-off-by: Steffen Trumtrar <s.trumtrar at pengutronix.de>
---
 scripts/Makefile        |  1 +
 scripts/zynq_checksum.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 73 insertions(+)
 create mode 100644 scripts/zynq_checksum.c

diff --git a/scripts/Makefile b/scripts/Makefile
index 08b325c..41c892e 100644
--- a/scripts/Makefile
+++ b/scripts/Makefile
@@ -12,6 +12,7 @@ hostprogs-$(CONFIG_ARCH_NETX)    += gen_netx_image
 hostprogs-$(CONFIG_ARCH_OMAP)    += omap_signGP mk-am35xx-spi-image
 hostprogs-$(CONFIG_ARCH_S5PCxx)  += s5p_cksum
 hostprogs-$(CONFIG_ARCH_DAVINCI) += mkublheader
+hostprogs-$(CONFIG_ARCH_ZYNQ)	 += zynq_checksum
 
 HOSTLOADLIBES_omap4_usbboot = -lpthread
 omap4_usbboot-objs               := usb_linux.o omap4_usbboot.o
diff --git a/scripts/zynq_checksum.c b/scripts/zynq_checksum.c
new file mode 100644
index 0000000..f32db61
--- /dev/null
+++ b/scripts/zynq_checksum.c
@@ -0,0 +1,72 @@
+#include <endian.h>
+#include <errno.h>
+#include <malloc.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+
+static void usage(char *name)
+{
+	printf("Usage: %s barebox.bin <outfile>\n", name);
+}
+
+int main(int argc, char *argv[])
+{
+	FILE *ifile, *ofile;
+	unsigned int *buf;
+	const char *infile;
+	const char *outfile;
+	struct stat st;
+	unsigned int i;
+	unsigned long sum = 0;
+
+	if (argc != 3) {
+		usage(argv[0]);
+		exit(1);
+	}
+
+	infile = argv[1];
+	outfile = argv[2];
+
+	if (stat(infile, &st) == -1) {
+		perror("stat");
+		exit(EXIT_FAILURE);
+	}
+
+	buf = malloc(sizeof(*buf) * st.st_size);
+	if (!buf) {
+		fprintf(stderr, "Unable to allocate buffer\n");
+		return -1;
+	}
+	ifile = fopen(infile, "rb");
+	if (!ifile) {
+		fprintf(stderr, "Cannot open %s for reading\n",
+			infile);
+		free(buf);
+		exit(EXIT_FAILURE);
+	}
+	ofile = fopen(outfile, "wb");
+	if (!ofile) {
+		fprintf(stderr, "Cannot open %s for writing\n",
+			outfile);
+		fclose(ifile);
+		free(buf);
+		exit(EXIT_FAILURE);
+	}
+
+	fread(buf, 4, st.st_size, ifile);
+
+	for (i = 0x8; i < 0x12; i++)
+		sum += htole32(buf[i]);
+
+	sum = ~sum;
+	buf[i] = sum;
+
+	fwrite(buf, st.st_size / 4, 4, ofile);
+
+	fclose(ofile);
+	fclose(ifile);
+	free(buf);
+
+	return 0;
+}
-- 
1.8.2.rc2