path: root/common/spl/spl.c

/*
 * (C) Copyright 2010
 * Texas Instruments, <www.ti.com>
 *
 * Aneesh V <aneesh@ti.com>
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */
#include <common.h>
#include <dm.h>
#include <spl.h>
#include <asm/u-boot.h>
#include <nand.h>
#include <fat.h>
#include <version.h>
#include <i2c.h>
#include <image.h>
#include <malloc.h>
#include <dm/root.h>
#include <linux/compiler.h>
#include <omap_remoteproc.h>
#include <fdt_support.h>
#include <asm/omap_sec_common.h>

DECLARE_GLOBAL_DATA_PTR;

#ifndef CONFIG_SYS_UBOOT_START
#define CONFIG_SYS_UBOOT_START	CONFIG_SYS_TEXT_BASE
#endif
#ifndef CONFIG_SYS_MONITOR_LEN
/* Unknown U-Boot size, let's assume it will not be more than 200 KB */
#define CONFIG_SYS_MONITOR_LEN	(200 * 1024)
#endif

u32 *boot_params_ptr = NULL;
struct spl_image_info spl_image;

/* Define board data structure */
static bd_t bdata __attribute__ ((section(".data")));

/*
 * Default function to determine if u-boot or the OS should
 * be started. This implementation always returns 1.
 *
 * Please implement your own board specific funcion to do this.
 *
 * RETURN
 * 0 to not start u-boot
 * positive if u-boot should start
 */
#ifdef CONFIG_SPL_OS_BOOT
__weak int spl_start_uboot(void)
{
	puts("SPL: Please implement spl_start_uboot() for your board\n");
	puts("SPL: Direct Linux boot not active!\n");
	return 1;
}
#endif

void spl_fixup_fdt(void)
{
#ifdef CONFIG_SPL_OF_LIBFDT
	void *fdt_blob = (void *)CONFIG_SYS_SPL_ARGS_ADDR;
	int err;

	err = fdt_check_header(fdt_blob);
	if (err < 0) {
		printf("fdt_root: %s\n", fdt_strerror(err));
		return;
	}

	/* fixup the memory dt node */
	err = fdt_shrink_to_minimum(fdt_blob);
	if (err == 0) {
		printf("spl: fdt_shrink_to_minimum err - %d\n", err);
		return;
	}

	err = arch_fixup_fdt(fdt_blob);
	if (err) {
		printf("spl: arch_fixup_fdt err - %d\n", err);
		return;
	}
#endif
}

/*
 * Weak default function for board specific cleanup/preparation before
 * Linux boot. Some boards/platforms might not need it, so just provide
 * an empty stub here.
 */
__weak void spl_board_prepare_for_linux(void)
{
	/* Nothing to do! */
}

__weak void spl_board_prepare_for_boot(void)
{
	/* Nothing to do! */
}

void spl_set_header_raw_uboot(void)
{
	spl_image.size = CONFIG_SYS_MONITOR_LEN;
	spl_image.entry_point = CONFIG_SYS_UBOOT_START;
	spl_image.load_addr = CONFIG_SYS_TEXT_BASE;
	spl_image.os = IH_OS_U_BOOT;
	spl_image.name = "U-Boot";
}

void spl_parse_image_header(const struct image_header *header)
{
#ifdef CONFIG_SPL_PANIC_ON_NON_FIT_IMAGE
	panic("** non-FIT images are not supported");
#else
	u32 header_size = sizeof(struct image_header);

	if (image_get_magic(header) == IH_MAGIC) {
		if (spl_image.flags & SPL_COPY_PAYLOAD_ONLY) {
			/*
			 * On some system (e.g. powerpc), the load-address and
			 * entry-point is located at address 0. We can't load
			 * to 0-0x40. So skip header in this case.
			 */
			spl_image.load_addr = image_get_load(header);
			spl_image.entry_point = image_get_ep(header);
			spl_image.size = image_get_data_size(header);
		} else {
			spl_image.entry_point = image_get_load(header);
			/* Load including the header */
			spl_image.load_addr = spl_image.entry_point -
				header_size;
			spl_image.size = image_get_data_size(header) +
				header_size;
		}
		spl_image.os = image_get_os(header);
		spl_image.name = image_get_name(header);
		debug("spl: payload image: %.*s load addr: 0x%x size: %d\n",
			(int)sizeof(spl_image.name), spl_image.name,
			spl_image.load_addr, spl_image.size);
#ifdef CONFIG_SPL_ANDROID_BOOT_SUPPORT
	} else if (genimg_get_format(header) == IMAGE_FORMAT_ANDROID) {
		ulong kern_start;
		android_image_get_kernel((const struct andr_img_hdr *)header,
					 true, &kern_start,
					 (ulong *)&spl_image.size);
		spl_image.entry_point = android_image_get_kload((const struct andr_img_hdr *)header);
		spl_image.load_addr = spl_image.entry_point - (kern_start - (ulong)header);
		spl_image.size += (kern_start - (ulong)header);
		spl_image.os = IH_OS_LINUX;
		spl_image.name = "Android Image";
		debug("spl: android image: %.*s load addr: 0x%x size: %d\n",
			sizeof(spl_image.name), spl_image.name,
			spl_image.load_addr, spl_image.size);
#endif
	} else {
#ifdef CONFIG_SPL_PANIC_ON_RAW_IMAGE
		/*
		 * CONFIG_SPL_PANIC_ON_RAW_IMAGE is defined when the
		 * code which loads images in SPL cannot guarantee that
		 * absolutely all read errors will be reported.
		 * An example is the LPC32XX MLC NAND driver, which
		 * will consider that a completely unreadable NAND block
		 * is bad, and thus should be skipped silently.
		 */
		panic("** no mkimage signature but raw image not supported");
#else
		/* Signature not found - assume u-boot.bin */
		debug("mkimage signature not found - ih_magic = %x\n",
			header->ih_magic);
		spl_set_header_raw_uboot();
#endif
	}
#endif
}

__weak void __noreturn jump_to_image_no_args(struct spl_image_info *spl_image)
{
	typedef void __noreturn (*image_entry_noargs_t)(void);

	image_entry_noargs_t image_entry =
		(image_entry_noargs_t)(unsigned long)spl_image->entry_point;

	debug("image entry point: 0x%X\n", spl_image->entry_point);
	image_entry();
}

#ifndef CONFIG_SPL_LOAD_FIT_ADDRESS
# define CONFIG_SPL_LOAD_FIT_ADDRESS	0
#endif

#if defined(CONFIG_SPL_RAM_DEVICE) || defined(CONFIG_SPL_DFU_SUPPORT)
static ulong spl_ram_load_read(struct spl_load_info *load, ulong sector,
			       ulong count, void *buf)
{
	debug("%s: sector %lx, count %lx, buf %lx\n",
	      __func__, sector, count, (ulong)buf);
	memcpy(buf, (void *)(CONFIG_SPL_LOAD_FIT_ADDRESS + sector), count);
	return count;
}

static int spl_ram_load_image(void)
{
	struct image_header *header;

	header = (struct image_header *)CONFIG_SPL_LOAD_FIT_ADDRESS;

	if (IS_ENABLED(CONFIG_SPL_LOAD_FIT) &&
	    image_get_magic(header) == FDT_MAGIC) {
		struct spl_load_info load;

		debug("Found FIT\n");
		load.bl_len = 1;
		load.read = spl_ram_load_read;
		spl_load_simple_fit(&load, 0, header);
	} else {
		debug("Legacy image\n");
		/*
		 * Get the header.  It will point to an address defined by
		 * handoff which will tell where the image located inside
		 * the flash. For now, it will temporary fixed to address
		 * pointed by U-Boot.
		 */
		header = (struct image_header *)
			(CONFIG_SYS_TEXT_BASE -	sizeof(struct image_header));

		spl_parse_image_header(header);
	}

	return 0;
}
#endif

void enable_firewall_non_emif(void)
{
#if defined(CONFIG_TI_SECURE_DEVICE)

	//Setting MPU FW for IPU2 boot space 0x94000000 to 0x99000000
	/*if(0 != secure_mpu_firewall_lock(1, FW_INITIATOR_MPU, FW_INITIATOR_READ,
												0x94000000,0x05000000))
		printf("MPU_FW Region 1 setting failed!\n");*/

	//Setting MPU FW for DSP2 boot space 0x9f000000 - 0xA0000000
	/*if(0 != secure_mpu_firewall_lock(2, FW_INITIATOR_MPU, FW_INITIATOR_READ,
												0x9f000000,0x01000000))
		printf("MPU_FW Region 2 setting failed!\n");*/

	//Set the MPU firewall for RVC frame buffers RVC pool1
	if(0 != secure_mpu_firewall_lock(3, FW_INITIATOR_MPU, FW_INITIATOR_READ,
												0x84000000,0x10000000))
		printf("MPU_FW Region 3 setting failed!\n");

	//Set the MPU firewall for  RVC pool2
	/*if(0 != secure_mpu_firewall_lock(4, FW_INITIATOR_MPU, FW_INITIATOR_READ,
												0xA0000000,0x02000000))
		printf("MPU_FW Region 4 setting failed!\n");*/

	//Enable the L4Per3 FW for VPE & VIP1 regions
	if(0 != secure_l4per3_firewall_lock())
		printf("L4PER3 FW setting failed!\n");

#endif
	return;

}

#ifdef CONFIG_LATE_ATTACH

/*
 * Loads the remotecores specified in the cores array.
 *
 * In case of failure, the core id array is OR'ed with an error code
 * to indicate that the load has failed.
 *
 * This information can be used to indicate status of the remotecore
 * load to the kernel.
 */
void spl_load_cores(u32 boot_device, u32 *cores, u32 numcores)
{
	u32 i = 0;

	for (i = 0; i < numcores ; i++) {
		u32 core = cores[i];
		if (spl_mmc_load_core(core, boot_device) ||
		    spl_boot_core(core)) {
			cores[i] = (cores[i] | SPL_CORE_LOAD_ERR_ID);
			printf("Error loading remotecore %s!,"
				 "Continuing with boot ...\n",
				 rproc_cfg_arr[core]->core_name);
		} else {
			debug("loading remote core %s successful\n",
			      rproc_cfg_arr[core]->core_name);
		}
	}

	enable_firewall_non_emif();

	return;
}
#endif

int spl_init(void)
{
	int ret;

	debug("spl_init()\n");
#if defined(CONFIG_SYS_MALLOC_F_LEN)
	gd->malloc_limit = CONFIG_SYS_MALLOC_F_LEN;
	gd->malloc_ptr = 0;
#endif
	if (CONFIG_IS_ENABLED(OF_CONTROL)) {
		ret = fdtdec_setup();
		if (ret) {
			debug("fdtdec_setup() returned error %d\n", ret);
			return ret;
		}
	}
	if (IS_ENABLED(CONFIG_SPL_DM)) {
		ret = dm_init_and_scan(true);
		if (ret) {
			debug("dm_init_and_scan() returned error %d\n", ret);
			return ret;
		}
	}
	gd->flags |= GD_FLG_SPL_INIT;

	return 0;
}

#ifndef BOOT_DEVICE_NONE
#define BOOT_DEVICE_NONE 0xdeadbeef
#endif

static u32 spl_boot_list[] = {
	BOOT_DEVICE_NONE,
	BOOT_DEVICE_NONE,
	BOOT_DEVICE_NONE,
	BOOT_DEVICE_NONE,
	BOOT_DEVICE_NONE,
};

__weak void board_boot_order(u32 *spl_boot_list)
{
	spl_boot_list[0] = spl_boot_device();
}

#ifdef CONFIG_SPL_BOARD_LOAD_IMAGE
__weak void spl_board_announce_boot_device(void) { }
#endif

#ifdef CONFIG_SPL_LIBCOMMON_SUPPORT
struct boot_device_name {
	u32 boot_dev;
	const char *name;
};

struct boot_device_name boot_name_table[] = {
#ifdef CONFIG_SPL_RAM_DEVICE
	{ BOOT_DEVICE_RAM, "RAM" },
#endif
#ifdef CONFIG_SPL_MMC_SUPPORT
	{ BOOT_DEVICE_MMC1, "MMC1" },
	{ BOOT_DEVICE_MMC2, "MMC2" },
	{ BOOT_DEVICE_MMC2_2, "MMC2_2" },
#endif
#ifdef CONFIG_SPL_NAND_SUPPORT
	{ BOOT_DEVICE_NAND, "NAND" },
#endif
#ifdef CONFIG_SPL_ONENAND_SUPPORT
	{ BOOT_DEVICE_ONENAND, "OneNAND" },
#endif
#ifdef CONFIG_SPL_NOR_SUPPORT
	{ BOOT_DEVICE_NOR, "NOR" },
#endif
#ifdef CONFIG_SPL_YMODEM_SUPPORT
	{ BOOT_DEVICE_UART, "UART" },
#endif
#ifdef CONFIG_SPL_SPI_SUPPORT
	{ BOOT_DEVICE_SPI, "SPI" },
#endif
#ifdef CONFIG_SPL_ETH_SUPPORT
#ifdef CONFIG_SPL_ETH_DEVICE
	{ BOOT_DEVICE_CPGMAC, "eth device" },
#else
	{ BOOT_DEVICE_CPGMAC, "net" },
#endif
#endif
#ifdef CONFIG_SPL_USBETH_SUPPORT
	{ BOOT_DEVICE_USBETH, "USB eth" },
#endif
#ifdef CONFIG_SPL_USB_SUPPORT
	{ BOOT_DEVICE_USB, "USB" },
#endif
#ifdef CONFIG_SPL_DFU_SUPPORT
	{ BOOT_DEVICE_DFU, "USB DFU" },
#endif
#ifdef CONFIG_SPL_SATA_SUPPORT
	{ BOOT_DEVICE_SATA, "SATA" },
#endif
	/* Keep this entry last */
	{ BOOT_DEVICE_NONE, "unknown boot device" },
};

static void announce_boot_device(u32 boot_device)
{
	int i;

	puts("Trying to boot from ");

#ifdef CONFIG_SPL_BOARD_LOAD_IMAGE
	if (boot_device == BOOT_DEVICE_BOARD) {
		spl_board_announce_boot_device();
		puts("\n");
		return;
	}
#endif
	for (i = 0; i < ARRAY_SIZE(boot_name_table) - 1; i++) {
		if (boot_name_table[i].boot_dev == boot_device)
			break;
	}

	printf("%s\n", boot_name_table[i].name);
}
#else
static inline void announce_boot_device(u32 boot_device) { }
#endif

#ifdef CONFIG_LATE_ATTACH
/* List the id of the remotecores that need to be earlybooted
 *  in this array. This array is global as the success/failure
 * of the early load operation is specified by updating this
 * array.
 */
u32 cores_to_boot[] = { IPU2, DSP1 };
#endif

static int spl_load_image(u32 boot_device)
{
#ifdef CONFIG_EARLY_VIDEO
	u32 load_size1 = 0;
	char *part1 = "video";
	u32 load_size2 = 0;
	char *part2 = "videodata";
#endif

	switch (boot_device) {
#ifdef CONFIG_SPL_RAM_DEVICE
	case BOOT_DEVICE_RAM:
		return spl_ram_load_image();
#endif
#ifdef CONFIG_SPL_MMC_SUPPORT
	case BOOT_DEVICE_MMC1:
	case BOOT_DEVICE_MMC2:
	case BOOT_DEVICE_MMC2_2:
#ifdef CONFIG_LATE_ATTACH
#ifdef CONFIG_EARLY_VIDEO
		spl_mmc_load_part(part1 , (u32 *)0xA2400000, &load_size1, boot_device);
		if (load_size1) {
			debug ("Loaded %d of %s partition \n", load_size1, part1);
		}
		spl_mmc_load_part(part2 , (u32 *)0xA3000000, &load_size2, boot_device);
		if (load_size2) {
			debug ("Loaded %d of %s partition \n", load_size2, part2);
		}
#endif
		spl_load_cores(boot_device, cores_to_boot,
			       sizeof(cores_to_boot)/sizeof(u32));
#endif
		return spl_mmc_load_image(boot_device);
#endif
#ifdef CONFIG_SPL_NAND_SUPPORT
	case BOOT_DEVICE_NAND:
		return spl_nand_load_image();
#endif
#ifdef CONFIG_SPL_ONENAND_SUPPORT
	case BOOT_DEVICE_ONENAND:
		return spl_onenand_load_image();
#endif
#ifdef CONFIG_SPL_NOR_SUPPORT
	case BOOT_DEVICE_NOR:
		return spl_nor_load_image();
#endif
#ifdef CONFIG_SPL_YMODEM_SUPPORT
	case BOOT_DEVICE_UART:
		return spl_ymodem_load_image();
#endif
#ifdef CONFIG_SPL_SPI_SUPPORT
	case BOOT_DEVICE_SPI:
		spl_setup_display();
#ifdef CONFIG_LATE_ATTACH
#ifdef CONFIG_EARLY_VIDEO
                spl_mmc_load_part(part1 , (u32 *)0xA2400000, &load_size1, boot_device);
                if (load_size1) {
                        debug ("Loaded %d of %s partition \n", load_size1, part1);
                }
                spl_mmc_load_part(part2 , (u32 *)0xA3000000, &load_size2, boot_device);
                if (load_size2) {
                        debug ("Loaded %d of %s partition \n", load_size2, part2);
                }
#endif
                spl_load_cores(boot_device, cores_to_boot,
                               sizeof(cores_to_boot)/sizeof(u32));
#endif
		return spl_spi_load_image();
#endif
#ifdef CONFIG_SPL_ETH_SUPPORT
	case BOOT_DEVICE_CPGMAC:
#ifdef CONFIG_SPL_ETH_DEVICE
		return spl_net_load_image(CONFIG_SPL_ETH_DEVICE);
#else
		return spl_net_load_image(NULL);
#endif
#endif
#ifdef CONFIG_SPL_USBETH_SUPPORT
	case BOOT_DEVICE_USBETH:
		return spl_net_load_image("usb_ether");
#endif
#ifdef CONFIG_SPL_USB_SUPPORT
	case BOOT_DEVICE_USB:
		return spl_usb_load_image();
#endif
#ifdef CONFIG_SPL_DFU_SUPPORT
	case BOOT_DEVICE_DFU:
		spl_dfu_cmd(0, "dfu_alt_info_ram", "ram", "0");
		return spl_ram_load_image();
#endif
#ifdef CONFIG_SPL_SATA_SUPPORT
	case BOOT_DEVICE_SATA:
		return spl_sata_load_image();
#endif
#ifdef CONFIG_SPL_BOARD_LOAD_IMAGE
	case BOOT_DEVICE_BOARD:
		return spl_board_load_image();
#endif
	default:
#if defined(CONFIG_SPL_SERIAL_SUPPORT) && defined(CONFIG_SPL_LIBCOMMON_SUPPORT)
		puts("SPL: Unsupported Boot Device!\n");
#endif
		return -ENODEV;
	}

	return -EINVAL;
}

#if !(defined(CONFIG_SYS_ICACHE_OFF) && defined(CONFIG_SYS_DCACHE_OFF)) && \
		defined(CONFIG_ARM)
static int reserve_mmu(void)
{
	phys_addr_t ram_top = 0;
	/* reserve TLB table */
	gd->arch.tlb_size = PGTABLE_SIZE;

#ifdef CONFIG_SYS_SDRAM_BASE
	ram_top = CONFIG_SYS_SDRAM_BASE;
#endif
	ram_top += get_effective_memsize();
	gd->arch.tlb_addr = ram_top - gd->arch.tlb_size;
	debug("TLB table from %08lx to %08lx\n", gd->arch.tlb_addr,
	      gd->arch.tlb_addr + gd->arch.tlb_size);
	return 0;
}

__weak void dram_init_banksize(void)
{
#if defined(CONFIG_NR_DRAM_BANKS) && defined(CONFIG_SYS_SDRAM_BASE)
	gd->bd->bi_dram[0].start = CONFIG_SYS_SDRAM_BASE;
	gd->bd->bi_dram[0].size = get_effective_memsize();
#endif
}

#endif

void board_init_r(gd_t *dummy1, ulong dummy2)
{
	int i;

	debug(">>spl:board_init_r()\n");
	gd->bd = &bdata;

#if !(defined(CONFIG_SYS_ICACHE_OFF) && defined(CONFIG_SYS_DCACHE_OFF)) && \
		defined(CONFIG_ARM)
	dram_init_banksize();
	reserve_mmu();
	enable_caches();
#endif

#if defined(CONFIG_SYS_SPL_MALLOC_START)
	mem_malloc_init(CONFIG_SYS_SPL_MALLOC_START,
			CONFIG_SYS_SPL_MALLOC_SIZE);
	gd->flags |= GD_FLG_FULL_MALLOC_INIT;
#endif
	if (!(gd->flags & GD_FLG_SPL_INIT)) {
		if (spl_init())
			hang();
	}
#ifndef CONFIG_PPC
	/*
	 * timer_init() does not exist on PPC systems. The timer is initialized
	 * and enabled (decrementer) in interrupt_init() here.
	 */
	timer_init();
#endif

#ifdef CONFIG_SPL_BOARD_INIT
	spl_board_init();
#endif

	board_boot_order(spl_boot_list);
	for (i = 0; i < ARRAY_SIZE(spl_boot_list) &&
			spl_boot_list[i] != BOOT_DEVICE_NONE; i++) {
		announce_boot_device(spl_boot_list[i]);
		if (!spl_load_image(spl_boot_list[i]))
			break;
	}

	if (i == ARRAY_SIZE(spl_boot_list) ||
	    spl_boot_list[i] == BOOT_DEVICE_NONE) {
		puts("SPL: failed to boot from all boot devices\n");
		hang();
	}

#if !(defined(CONFIG_SYS_ICACHE_OFF) && defined(CONFIG_SYS_DCACHE_OFF)) && \
		defined(CONFIG_ARM)
	cleanup_before_linux();
#endif

	switch (spl_image.os) {
	case IH_OS_U_BOOT:
		debug("Jumping to U-Boot\n");
		break;
#ifdef CONFIG_SPL_OS_BOOT
	case IH_OS_LINUX:
		debug("Jumping to Linux\n");
		spl_fixup_fdt();
		spl_board_prepare_for_linux();
		jump_to_image_linux((void *)CONFIG_SYS_SPL_ARGS_ADDR);
#endif
	default:
		debug("Unsupported OS image.. Jumping nevertheless..\n");
	}
#if defined(CONFIG_SYS_MALLOC_F_LEN) && !defined(CONFIG_SYS_SPL_MALLOC_SIZE)
	debug("SPL malloc() used %#lx bytes (%ld KB)\n", gd->malloc_ptr,
	      gd->malloc_ptr / 1024);
#endif

	debug("loaded - jumping to U-Boot...");
	spl_board_prepare_for_boot();
	jump_to_image_no_args(&spl_image);
}

/*
 * This requires UART clocks to be enabled.  In order for this to work the
 * caller must ensure that the gd pointer is valid.
 */
void preloader_console_init(void)
{
	gd->baudrate = CONFIG_BAUDRATE;

	serial_init();		/* serial communications setup */

	gd->have_console = 1;

	puts("\nU-Boot SPL " PLAIN_VERSION " (" U_BOOT_DATE " - " \
			U_BOOT_TIME ")\n");
#ifdef CONFIG_SPL_DISPLAY_PRINT
	spl_display_print();
#endif
}

/**
 * spl_relocate_stack_gd() - Relocate stack ready for board_init_r() execution
 *
 * Sometimes board_init_f() runs with a stack in SRAM but we want to use SDRAM
 * for the main board_init_r() execution. This is typically because we need
 * more stack space for things like the MMC sub-system.
 *
 * This function calculates the stack position, copies the global_data into
 * place, sets the new gd (except for ARM, for which setting GD within a C
 * function may not always work) and returns the new stack position. The
 * caller is responsible for setting up the sp register and, in the case
 * of ARM, setting up gd.
 *
 * All of this is done using the same layout and alignments as done in
 * board_init_f_init_reserve() / board_init_f_alloc_reserve().
 *
 * @return new stack location, or 0 to use the same stack
 */
ulong spl_relocate_stack_gd(void)
{
#ifdef CONFIG_SPL_STACK_R
	gd_t *new_gd;
	ulong ptr = CONFIG_SPL_STACK_R_ADDR;

#ifdef CONFIG_SPL_SYS_MALLOC_SIMPLE
	if (CONFIG_SPL_STACK_R_MALLOC_SIMPLE_LEN) {
		if (!(gd->flags & GD_FLG_SPL_INIT))
			panic_str("spl_init must be called before heap reloc");

		ptr -= CONFIG_SPL_STACK_R_MALLOC_SIMPLE_LEN;
		gd->malloc_base = ptr;
		gd->malloc_limit = CONFIG_SPL_STACK_R_MALLOC_SIMPLE_LEN;
		gd->malloc_ptr = 0;
	}
#endif
	/* Get stack position: use 8-byte alignment for ABI compliance */
	ptr = CONFIG_SPL_STACK_R_ADDR - roundup(sizeof(gd_t),16);
	new_gd = (gd_t *)ptr;
	memcpy(new_gd, (void *)gd, sizeof(gd_t));
#if !defined(CONFIG_ARM)
	gd = new_gd;
#endif
	return ptr;
#else
	return 0;
#endif
}