avionic design with actual uboot and tooling

submodule of avionic design uboot bootloader and with included tools to
get you started , read readme.md and readme-tk1-loader.md

u-boot/arch/arm/imx-common/imx_bootaux.c

@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2016 Freescale Semiconductor, Inc.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <command.h>
+
+/* Allow for arch specific config before we boot */
+static int __arch_auxiliary_core_up(u32 core_id, u32 boot_private_data)
+{
+	/* please define platform specific arch_auxiliary_core_up() */
+	return CMD_RET_FAILURE;
+}
+
+int arch_auxiliary_core_up(u32 core_id, u32 boot_private_data)
+	__attribute__((weak, alias("__arch_auxiliary_core_up")));
+
+/* Allow for arch specific config before we boot */
+static int __arch_auxiliary_core_check_up(u32 core_id)
+{
+	/* please define platform specific arch_auxiliary_core_check_up() */
+	return 0;
+}
+
+int arch_auxiliary_core_check_up(u32 core_id)
+	__attribute__((weak, alias("__arch_auxiliary_core_check_up")));
+
+/*
+ * To i.MX6SX and i.MX7D, the image supported by bootaux needs
+ * the reset vector at the head for the image, with SP and PC
+ * as the first two words.
+ *
+ * Per the cortex-M reference manual, the reset vector of M4 needs
+ * to exist at 0x0 (TCMUL). The PC and SP are the first two addresses
+ * of that vector.  So to boot M4, the A core must build the M4's reset
+ * vector with getting the PC and SP from image and filling them to
+ * TCMUL. When M4 is kicked, it will load the PC and SP by itself.
+ * The TCMUL is mapped to (M4_BOOTROM_BASE_ADDR) at A core side for
+ * accessing the M4 TCMUL.
+ */
+int do_bootaux(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	ulong addr;
+	int ret, up;
+
+	if (argc < 2)
+		return CMD_RET_USAGE;
+
+	up = arch_auxiliary_core_check_up(0);
+	if (up) {
+		printf("## Auxiliary core is already up\n");
+		return CMD_RET_SUCCESS;
+	}
+
+	addr = simple_strtoul(argv[1], NULL, 16);
+
+	printf("## Starting auxiliary core at 0x%08lX ...\n", addr);
+
+	ret = arch_auxiliary_core_up(0, addr);
+	if (ret)
+		return CMD_RET_FAILURE;
+
+	return CMD_RET_SUCCESS;
+}
+
+U_BOOT_CMD(
+	bootaux, CONFIG_SYS_MAXARGS, 1,	do_bootaux,
+	"Start auxiliary core",
+	""
+);