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/sandbox/cpu/cpu.c

@@ -0,0 +1,138 @@
+/*
+ * Copyright (c) 2011 The Chromium OS Authors.
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+#define DEBUG
+#include <common.h>
+#include <dm/root.h>
+#include <os.h>
+#include <asm/io.h>
+#include <asm/state.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/* Enable access to PCI memory with map_sysmem() */
+static bool enable_pci_map;
+
+#ifdef CONFIG_PCI
+/* Last device that was mapped into memory, and length of mapping */
+static struct udevice *map_dev;
+unsigned long map_len;
+#endif
+
+void sandbox_exit(void)
+{
+	/* Do this here while it still has an effect */
+	os_fd_restore();
+	if (state_uninit())
+		os_exit(2);
+
+	if (dm_uninit())
+		os_exit(2);
+
+	/* This is considered normal termination for now */
+	os_exit(0);
+}
+
+/* delay x useconds */
+void __udelay(unsigned long usec)
+{
+	struct sandbox_state *state = state_get_current();
+
+	if (!state->skip_delays)
+		os_usleep(usec);
+}
+
+int cleanup_before_linux(void)
+{
+	return 0;
+}
+
+int cleanup_before_linux_select(int flags)
+{
+	return 0;
+}
+
+void *map_physmem(phys_addr_t paddr, unsigned long len, unsigned long flags)
+{
+#ifdef CONFIG_PCI
+	unsigned long plen = len;
+	void *ptr;
+
+	map_dev = NULL;
+	if (enable_pci_map && !pci_map_physmem(paddr, &len, &map_dev, &ptr)) {
+		if (plen != len) {
+			printf("%s: Warning: partial map at %x, wanted %lx, got %lx\n",
+			       __func__, paddr, len, plen);
+		}
+		map_len = len;
+		return ptr;
+	}
+#endif
+
+	return (void *)(gd->arch.ram_buf + paddr);
+}
+
+void unmap_physmem(const void *vaddr, unsigned long flags)
+{
+#ifdef CONFIG_PCI
+	if (map_dev) {
+		pci_unmap_physmem(vaddr, map_len, map_dev);
+		map_dev = NULL;
+	}
+#endif
+}
+
+void sandbox_set_enable_pci_map(int enable)
+{
+	enable_pci_map = enable;
+}
+
+phys_addr_t map_to_sysmem(const void *ptr)
+{
+	return (u8 *)ptr - gd->arch.ram_buf;
+}
+
+void flush_dcache_range(unsigned long start, unsigned long stop)
+{
+}
+
+int sandbox_read_fdt_from_file(void)
+{
+	struct sandbox_state *state = state_get_current();
+	const char *fname = state->fdt_fname;
+	void *blob;
+	loff_t size;
+	int err;
+	int fd;
+
+	blob = map_sysmem(CONFIG_SYS_FDT_LOAD_ADDR, 0);
+	if (!state->fdt_fname) {
+		err = fdt_create_empty_tree(blob, 256);
+		if (!err)
+			goto done;
+		printf("Unable to create empty FDT: %s\n", fdt_strerror(err));
+		return -EINVAL;
+	}
+
+	err = os_get_filesize(fname, &size);
+	if (err < 0) {
+		printf("Failed to file FDT file '%s'\n", fname);
+		return err;
+	}
+	fd = os_open(fname, OS_O_RDONLY);
+	if (fd < 0) {
+		printf("Failed to open FDT file '%s'\n", fname);
+		return -EACCES;
+	}
+	if (os_read(fd, blob, size) != size) {
+		os_close(fd);
+		return -EIO;
+	}
+	os_close(fd);
+
+done:
+	gd->fdt_blob = blob;
+
+	return 0;
+}