bmode-usb: add recipe to set i.mx 6 boot mode

This linux userspace tool does what U-Boot's 'bmode usb noreset' does.
On the next reboot the i.MX 6 will boot to recovery aka serial download
mode.

Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>
Signed-off-by: Stefan Agner <stefan.agner@toradex.com>

1 files changed, 45 insertions, 0 deletions

diff --git a/recipes-support/bmode-usb/bmode-usb/bmode_usb.c b/recipes-support/bmode-usb/bmode-usb/bmode_usb.c
new file mode 100644
index 0000000..c8ca7e2
--- /dev/null
+++ b/recipes-support/bmode-usb/bmode-usb/bmode_usb.c
@@ -0,0 +1,45 @@
+/*
+ * Copyright 2017 Toradex AG.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+/*
+ * Running this will set GPR9/GPR10 to values which will make the module
+ * go to recovery mode on next reboot.
+ * It has the same effect as 'bmode usb noreset' in U-Boot
+ *
+ * $ arm-linux-gnueabihf-gcc -o bmode_usb bmode_usb.c
+ * $ arm-linux-gnueabihf-strip bmode_usb
+ */
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+/* valid for i.MX6DL/i.MX6Q */
+#define SRC_BASE_ADDR	0x020D8000
+#define SRC_GPR9_OFF	(0x40/4)
+#define SRC_GPR10_OFF	(0x44/4)
+
+int main(void)
+{
+	int fd;
+	unsigned reg;
+	unsigned *src;
+
+	fd = open("/dev/mem", O_RDWR);
+	src = (unsigned *)mmap(0, SRC_GPR10_OFF + 4, PROT_READ|PROT_WRITE,
+			       MAP_SHARED, fd, 0x020D8000);
+	if(src == NULL) {
+		printf("Failed to mmap register\n");
+		return -1;
+	}
+
+	src[SRC_GPR9_OFF] = 0x10;
+	src[SRC_GPR10_OFF] |= 0x10000000;
+
+	printf("Next reboot (not powercycle!) will boot to recovery mode\n");
+	return 0;
+}