pico-imx6: Add Falcon mode

Add Falcon mode support, which allows the SPL to load and
jump to the Linux kernel directly, without the need of loading
U-Boot proper.

CONFIG_SPL_OS_BOOT=y needs to be passed in the defconfig
in order to use Falcon mode.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
diff --git a/board/technexion/pico-imx6/spl.c b/board/technexion/pico-imx6/spl.c
index 5bf8702..06ad0a8 100644
--- a/board/technexion/pico-imx6/spl.c
+++ b/board/technexion/pico-imx6/spl.c
@@ -27,6 +27,17 @@
 #define IMX6DQ_DRIVE_STRENGTH		0x30
 #define IMX6SDL_DRIVE_STRENGTH		0x28
 
+#ifdef CONFIG_SPL_OS_BOOT
+int spl_start_uboot(void)
+{
+	/* Break into full U-Boot on 'c' */
+	if (serial_tstc() && serial_getc() == 'c')
+		return 1;
+
+	return 0;
+}
+#endif
+
 /* configure MX6Q/DUAL mmdc DDR io registers */
 static struct mx6dq_iomux_ddr_regs mx6dq_ddr_ioregs = {
 	.dram_sdclk_0 = IMX6DQ_DRIVE_STRENGTH,