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/arc/lib/bootm.c

@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2013-2014 Synopsys, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+static ulong get_sp(void)
+{
+	ulong ret;
+
+	asm("mov %0, sp" : "=r"(ret) : );
+	return ret;
+}
+
+void arch_lmb_reserve(struct lmb *lmb)
+{
+	ulong sp;
+
+	/*
+	 * Booting a (Linux) kernel image
+	 *
+	 * Allocate space for command line and board info - the
+	 * address should be as high as possible within the reach of
+	 * the kernel (see CONFIG_SYS_BOOTMAPSZ settings), but in unused
+	 * memory, which means far enough below the current stack
+	 * pointer.
+	 */
+	sp = get_sp();
+	debug("## Current stack ends at 0x%08lx ", sp);
+
+	/* adjust sp by 4K to be safe */
+	sp -= 4096;
+	lmb_reserve(lmb, sp, (CONFIG_SYS_SDRAM_BASE + gd->ram_size - sp));
+}
+
+static int cleanup_before_linux(void)
+{
+	disable_interrupts();
+	flush_dcache_all();
+	invalidate_icache_all();
+
+	return 0;
+}
+
+/* Subcommand: PREP */
+static void boot_prep_linux(bootm_headers_t *images)
+{
+	if (image_setup_linux(images))
+		hang();
+}
+
+__weak void smp_set_core_boot_addr(unsigned long addr, int corenr) {}
+__weak void smp_kick_all_cpus(void) {}
+
+/* Subcommand: GO */
+static void boot_jump_linux(bootm_headers_t *images, int flag)
+{
+	void (*kernel_entry)(int zero, int arch, uint params);
+	unsigned int r0, r2;
+	int fake = (flag & BOOTM_STATE_OS_FAKE_GO);
+
+	kernel_entry = (void (*)(int, int, uint))images->ep;
+
+	debug("## Transferring control to Linux (at address %08lx)...\n",
+	      (ulong) kernel_entry);
+	bootstage_mark(BOOTSTAGE_ID_RUN_OS);
+
+	printf("\nStarting kernel ...%s\n\n", fake ?
+	       "(fake run for tracing)" : "");
+	bootstage_mark_name(BOOTSTAGE_ID_BOOTM_HANDOFF, "start_kernel");
+
+	cleanup_before_linux();
+
+	if (IMAGE_ENABLE_OF_LIBFDT && images->ft_len) {
+		r0 = 2;
+		r2 = (unsigned int)images->ft_addr;
+	} else {
+		r0 = 1;
+		r2 = (unsigned int)getenv("bootargs");
+	}
+
+	smp_set_core_boot_addr((unsigned long)kernel_entry, -1);
+	smp_kick_all_cpus();
+
+	if (!fake)
+		kernel_entry(r0, 0, r2);
+}
+
+int do_bootm_linux(int flag, int argc, char *argv[], bootm_headers_t *images)
+{
+	/* No need for those on ARC */
+	if ((flag & BOOTM_STATE_OS_BD_T) || (flag & BOOTM_STATE_OS_CMDLINE))
+		return -1;
+
+	if (flag & BOOTM_STATE_OS_PREP) {
+		boot_prep_linux(images);
+		return 0;
+	}
+
+	if (flag & (BOOTM_STATE_OS_GO | BOOTM_STATE_OS_FAKE_GO)) {
+		boot_jump_linux(images, flag);
+		return 0;
+	}
+
+	boot_prep_linux(images);
+	boot_jump_linux(images, flag);
+	return 0;
+}