tools/rkcommon.c - filogic/uboot - Gitiles

 /*
  * (C) Copyright 2015 Google,  Inc
  * Written by Simon Glass <sjg@chromium.org>
  *
  * (C) 2017 Theobroma Systems Design und Consulting GmbH
  *
  * SPDX-License-Identifier:	GPL-2.0+
  *
  * Helper functions for Rockchip images
  */

 #include "imagetool.h"
 #include <image.h>
 #include <rc4.h>
 #include "mkimage.h"
 #include "rkcommon.h"

 #define DIV_ROUND_UP(n, d)	(((n) + (d) - 1) / (d))

 enum {
 	RK_SIGNATURE		= 0x0ff0aa55,
 };

 /**
  * struct header0_info - header block for boot ROM
  *
  * This is stored at SD card block 64 (where each block is 512 bytes, or at
  * the start of SPI flash. It is encoded with RC4.
  *
  * @signature:		Signature (must be RKSD_SIGNATURE)
  * @disable_rc4:	0 to use rc4 for boot image,  1 to use plain binary
  * @init_offset:	Offset in blocks of the SPL code from this header
  *			block. E.g. 4 means 2KB after the start of this header.
  * Other fields are not used by U-Boot
  */
 struct header0_info {
 	uint32_t signature;
 	uint8_t reserved[4];
 	uint32_t disable_rc4;
 	uint16_t init_offset;
 	uint8_t reserved1[492];
 	uint16_t init_size;
 	uint16_t init_boot_size;
 	uint8_t reserved2[2];
 };

 /**
  * struct header1_info
  */
 struct header1_info {
 	uint32_t magic;
 };

 /**
  * struct spl_info - spl info for each chip
  *
  * @imagename:		Image name(passed by "mkimage -n")
  * @spl_hdr:		Boot ROM requires a 4-bytes spl header
  * @spl_size:		Spl size(include extra 4-bytes spl header)
  * @spl_rc4:		RC4 encode the SPL binary (same key as header)
  * @spl_boot0:          A new-style (ARM_SOC_BOOT0_HOOK) image that should
  *                      have the boot magic (e.g. 'RK33') written to its first
  *                      word.
  */

 struct spl_info {
 	const char *imagename;
 	const char *spl_hdr;
 	const uint32_t spl_size;
 	const bool spl_rc4;
 	const bool spl_boot0;
 };

 static struct spl_info spl_infos[] = {
 	{ "rk3036", "RK30", 0x1000, false, false },
 	{ "rk3188", "RK31", 0x8000 - 0x800, true, false },
 	{ "rk3288", "RK32", 0x8000, false, false },
 	{ "rk3328", "RK32", 0x8000 - 0x1000, false, false },
 	{ "rk3399", "RK33", 0x20000, false, true },
 	{ "rv1108", "RK11", 0x1800, false, false},
 };

 static unsigned char rc4_key[16] = {
 	124, 78, 3, 4, 85, 5, 9, 7,
 	45, 44, 123, 56, 23, 13, 23, 17
 };

 static struct spl_info *rkcommon_get_spl_info(char *imagename)
 {
 	int i;

 	if (!imagename)
 		return NULL;

 	for (i = 0; i < ARRAY_SIZE(spl_infos); i++)
 		if (!strncmp(imagename, spl_infos[i].imagename, 6))
 			return spl_infos + i;

 	return NULL;
 }

 int rkcommon_check_params(struct image_tool_params *params)
 {
 	int i;

 	if (rkcommon_get_spl_info(params->imagename) != NULL)
 		return EXIT_SUCCESS;

 	/*
 	 * If this is a operation (list or extract), the don't require
 	 * imagename to be set.
 	 */
 	if (params->lflag || params->iflag)
 		return EXIT_SUCCESS;

 	fprintf(stderr, "ERROR: imagename (%s) is not supported!\n",
 		params->imagename ? params->imagename : "NULL");

 	fprintf(stderr, "Available imagename:");
 	for (i = 0; i < ARRAY_SIZE(spl_infos); i++)
 		fprintf(stderr, "\t%s", spl_infos[i].imagename);
 	fprintf(stderr, "\n");

 	return EXIT_FAILURE;
 }

 const char *rkcommon_get_spl_hdr(struct image_tool_params *params)
 {
 	struct spl_info *info = rkcommon_get_spl_info(params->imagename);

 	/*
 	 * info would not be NULL, because of we checked params before.
 	 */
 	return info->spl_hdr;
 }


 int rkcommon_get_spl_size(struct image_tool_params *params)
 {
 	struct spl_info *info = rkcommon_get_spl_info(params->imagename);

 	/*
 	 * info would not be NULL, because of we checked params before.
 	 */
 	return info->spl_size;
 }

 bool rkcommon_need_rc4_spl(struct image_tool_params *params)
 {
 	struct spl_info *info = rkcommon_get_spl_info(params->imagename);

 	/*
 	 * info would not be NULL, because of we checked params before.
 	 */
 	return info->spl_rc4;
 }

 bool rkcommon_spl_is_boot0(struct image_tool_params *params)
 {
 	struct spl_info *info = rkcommon_get_spl_info(params->imagename);

 	/*
 	 * info would not be NULL, because of we checked params before.
 	 */
 	return info->spl_boot0;
 }

 static void rkcommon_set_header0(void *buf, uint file_size,
 				 struct image_tool_params *params)
 {
 	struct header0_info *hdr = buf;

 	memset(buf, '\0', RK_INIT_OFFSET * RK_BLK_SIZE);
 	hdr->signature = RK_SIGNATURE;
 	hdr->disable_rc4 = !rkcommon_need_rc4_spl(params);
 	hdr->init_offset = RK_INIT_OFFSET;

 	hdr->init_size = DIV_ROUND_UP(file_size, RK_BLK_SIZE);
 	/*
 	 * The init_size has to be a multiple of 4 blocks (i.e. of 2K)
 	 * or the BootROM will not boot the image.
 	 *
 	 * Note: To verify that this is not a legacy constraint, we
 	 *       rechecked this against the RK3399 BootROM.
 	 */
 	hdr->init_size = ROUND(hdr->init_size, 4);
 	/*
 	 * init_boot_size needs to be set, as it is read by the BootROM
 	 * to determine the size of the next-stage bootloader (e.g. U-Boot
 	 * proper), when used with the back-to-bootrom functionality.
 	 *
 	 * see https://lists.denx.de/pipermail/u-boot/2017-May/293267.html
 	 * for a more detailed explanation by Andy Yan
 	 */
 	hdr->init_boot_size = hdr->init_size + RK_MAX_BOOT_SIZE / RK_BLK_SIZE;

 	rc4_encode(buf, RK_BLK_SIZE, rc4_key);
 }

 int rkcommon_set_header(void *buf, uint file_size,
 			struct image_tool_params *params)
 {
 	struct header1_info *hdr = buf + RK_SPL_HDR_START;

 	if (file_size > rkcommon_get_spl_size(params))
 		return -ENOSPC;

 	rkcommon_set_header0(buf, file_size, params);

 	/* Set up the SPL name (i.e. copy spl_hdr over) */
 	memcpy(&hdr->magic, rkcommon_get_spl_hdr(params), RK_SPL_HDR_SIZE);

 	if (rkcommon_need_rc4_spl(params))
 		rkcommon_rc4_encode_spl(buf, RK_SPL_HDR_START,
 					params->file_size - RK_SPL_HDR_START);

 	return 0;
 }

 static inline unsigned rkcommon_offset_to_spi(unsigned offset)
 {
 	/*
 	 * While SD/MMC images use a flat addressing, SPI images are padded
 	 * to use the first 2K of every 4K sector only.
 	 */
 	return ((offset & ~0x7ff) << 1) + (offset & 0x7ff);
 }

 static inline unsigned rkcommon_spi_to_offset(unsigned offset)
 {
 	return ((offset & ~0x7ff) >> 1) + (offset & 0x7ff);
 }

 static int rkcommon_parse_header(const void *buf, struct header0_info *header0,
 				 struct spl_info **spl_info)
 {
 	unsigned hdr1_offset;
 	struct header1_info *hdr1_sdmmc, *hdr1_spi;
 	int i;

 	if (spl_info)
 		*spl_info = NULL;

 	/*
 	 * The first header (hdr0) is always RC4 encoded, so try to decrypt
 	 * with the well-known key.
 	 */
 	memcpy((void *)header0, buf, sizeof(struct header0_info));
 	rc4_encode((void *)header0, sizeof(struct header0_info), rc4_key);

 	if (header0->signature != RK_SIGNATURE)
 		return -EPROTO;

 	/* We don't support RC4 encoded image payloads here, yet... */
 	if (header0->disable_rc4 == 0)
 		return -ENOSYS;

 	hdr1_offset = header0->init_offset * RK_BLK_SIZE;
 	hdr1_sdmmc = (struct header1_info *)(buf + hdr1_offset);
 	hdr1_spi = (struct header1_info *)(buf +
 					   rkcommon_offset_to_spi(hdr1_offset));

 	for (i = 0; i < ARRAY_SIZE(spl_infos); i++) {
 		if (!memcmp(&hdr1_sdmmc->magic, spl_infos[i].spl_hdr, 4)) {
 			if (spl_info)
 				*spl_info = &spl_infos[i];
 			return IH_TYPE_RKSD;
 		} else if (!memcmp(&hdr1_spi->magic, spl_infos[i].spl_hdr, 4)) {
 			if (spl_info)
 				*spl_info = &spl_infos[i];
 			return IH_TYPE_RKSPI;
 		}
 	}

 	return -1;
 }

 int rkcommon_verify_header(unsigned char *buf, int size,
 			   struct image_tool_params *params)
 {
 	struct header0_info header0;
 	struct spl_info *img_spl_info, *spl_info;
 	int ret;

 	ret = rkcommon_parse_header(buf, &header0, &img_spl_info);

 	/* If this is the (unimplemented) RC4 case, then rewrite the result */
 	if (ret == -ENOSYS)
 		return 0;

 	if (ret < 0)
 		return ret;

 	/*
 	 * If no 'imagename' is specified via the commandline (e.g. if this is
 	 * 'dumpimage -l' w/o any further constraints), we accept any spl_info.
 	 */
 	if (params->imagename == NULL)
 		return 0;

 	/* Match the 'imagename' against the 'spl_hdr' found */
 	spl_info = rkcommon_get_spl_info(params->imagename);
 	if (spl_info && img_spl_info)
 		return strcmp(spl_info->spl_hdr, img_spl_info->spl_hdr);

 	return -ENOENT;
 }

 void rkcommon_print_header(const void *buf)
 {
 	struct header0_info header0;
 	struct spl_info *spl_info;
 	uint8_t image_type;
 	int ret;

 	ret = rkcommon_parse_header(buf, &header0, &spl_info);

 	/* If this is the (unimplemented) RC4 case, then fail silently */
 	if (ret == -ENOSYS)
 		return;

 	if (ret < 0) {
 		fprintf(stderr, "Error: image verification failed\n");
 		return;
 	}

 	image_type = ret;

 	printf("Image Type:   Rockchip %s (%s) boot image\n",
 	       spl_info->spl_hdr,
 	       (image_type == IH_TYPE_RKSD) ? "SD/MMC" : "SPI");
 	printf("Data Size:    %d bytes\n", header0.init_size * RK_BLK_SIZE);
 }

 void rkcommon_rc4_encode_spl(void *buf, unsigned int offset, unsigned int size)
 {
 	unsigned int remaining = size;

 	while (remaining > 0) {
 		int step = (remaining > RK_BLK_SIZE) ? RK_BLK_SIZE : remaining;

 		rc4_encode(buf + offset, step, rc4_key);
 		offset += RK_BLK_SIZE;
 		remaining -= step;
 	}
 }

 int rkcommon_vrec_header(struct image_tool_params *params,
 			 struct image_type_params *tparams,
 			 unsigned int alignment)
 {
 	unsigned int  unpadded_size;
 	unsigned int  padded_size;

 	/*
 	 * The SPL image looks as follows:
 	 *
 	 * 0x0    header0 (see rkcommon.c)
 	 * 0x800  spl_name ('RK30', ..., 'RK33')
 	 *        (start of the payload for AArch64 payloads: we expect the
 	 *        first 4 bytes to be available for overwriting with our
 	 *        spl_name)
 	 * 0x804  first instruction to be executed
 	 *        (start of the image/payload for 32bit payloads)
 	 *
 	 * For AArch64 (ARMv8) payloads, natural alignment (8-bytes) is
 	 * required for its sections (so the image we receive needs to
 	 * have the first 4 bytes reserved for the spl_name).  Reserving
 	 * these 4 bytes is done using the BOOT0_HOOK infrastructure.
 	 *
 	 * Depending on this, the header is either 0x800 (if this is a
 	 * 'boot0'-style payload, which has reserved 4 bytes at the
 	 * beginning for the 'spl_name' and expects us to overwrite
 	 * its first 4 bytes) or 0x804 bytes in length.
 	 */
 	if (rkcommon_spl_is_boot0(params))
 		tparams->header_size = RK_SPL_HDR_START;
 	else
 		tparams->header_size = RK_SPL_HDR_START + 4;

 	/* Allocate, clear and install the header */
 	tparams->hdr = malloc(tparams->header_size);
 	if (!tparams->hdr)
 		return -ENOMEM;
 	memset(tparams->hdr, 0, tparams->header_size);

 	/*
 	 * If someone passed in 0 for the alignment, we'd better handle
 	 * it correctly...
 	 */
 	if (!alignment)
 		alignment = 1;

 	unpadded_size = tparams->header_size + params->file_size;
 	padded_size = ROUND(unpadded_size, alignment);

 	return padded_size - unpadded_size;
 }
	/*
	* (C) Copyright 2015 Google, Inc
	* Written by Simon Glass <sjg@chromium.org>
	*
	* (C) 2017 Theobroma Systems Design und Consulting GmbH
	*
	* SPDX-License-Identifier: GPL-2.0+
	*
	* Helper functions for Rockchip images
	*/

	#include "imagetool.h"
	#include <image.h>
	#include <rc4.h>
	#include "mkimage.h"
	#include "rkcommon.h"

	#define DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))

	enum {
	RK_SIGNATURE = 0x0ff0aa55,
	};

	/**
	* struct header0_info - header block for boot ROM
	*
	* This is stored at SD card block 64 (where each block is 512 bytes, or at
	* the start of SPI flash. It is encoded with RC4.
	*
	* @signature: Signature (must be RKSD_SIGNATURE)
	* @disable_rc4: 0 to use rc4 for boot image, 1 to use plain binary
	* @init_offset: Offset in blocks of the SPL code from this header
	* block. E.g. 4 means 2KB after the start of this header.
	* Other fields are not used by U-Boot
	*/
	struct header0_info {
	uint32_t signature;
	uint8_t reserved[4];
	uint32_t disable_rc4;
	uint16_t init_offset;
	uint8_t reserved1[492];
	uint16_t init_size;
	uint16_t init_boot_size;
	uint8_t reserved2[2];
	};

	/**
	* struct header1_info
	*/
	struct header1_info {
	uint32_t magic;
	};

	/**
	* struct spl_info - spl info for each chip
	*
	* @imagename: Image name(passed by "mkimage -n")
	* @spl_hdr: Boot ROM requires a 4-bytes spl header
	* @spl_size: Spl size(include extra 4-bytes spl header)
	* @spl_rc4: RC4 encode the SPL binary (same key as header)
	* @spl_boot0: A new-style (ARM_SOC_BOOT0_HOOK) image that should
	* have the boot magic (e.g. 'RK33') written to its first
	* word.
	*/

	struct spl_info {
	const char *imagename;
	const char *spl_hdr;
	const uint32_t spl_size;
	const bool spl_rc4;
	const bool spl_boot0;
	};

	static struct spl_info spl_infos[] = {
	{ "rk3036", "RK30", 0x1000, false, false },
	{ "rk3188", "RK31", 0x8000 - 0x800, true, false },
	{ "rk3288", "RK32", 0x8000, false, false },
	{ "rk3328", "RK32", 0x8000 - 0x1000, false, false },
	{ "rk3399", "RK33", 0x20000, false, true },
	{ "rv1108", "RK11", 0x1800, false, false},
	};

	static unsigned char rc4_key[16] = {
	124, 78, 3, 4, 85, 5, 9, 7,
	45, 44, 123, 56, 23, 13, 23, 17
	};

	static struct spl_info rkcommon_get_spl_info(char imagename)
	{
	int i;

	if (!imagename)
	return NULL;

	for (i = 0; i < ARRAY_SIZE(spl_infos); i++)
	if (!strncmp(imagename, spl_infos[i].imagename, 6))
	return spl_infos + i;

	return NULL;
	}

	int rkcommon_check_params(struct image_tool_params *params)
	{
	int i;

	if (rkcommon_get_spl_info(params->imagename) != NULL)
	return EXIT_SUCCESS;

	/*
	* If this is a operation (list or extract), the don't require
	* imagename to be set.
	*/
	if (params->lflag \|\| params->iflag)
	return EXIT_SUCCESS;

	fprintf(stderr, "ERROR: imagename (%s) is not supported!\n",
	params->imagename ? params->imagename : "NULL");

	fprintf(stderr, "Available imagename:");
	for (i = 0; i < ARRAY_SIZE(spl_infos); i++)
	fprintf(stderr, "\t%s", spl_infos[i].imagename);
	fprintf(stderr, "\n");

	return EXIT_FAILURE;
	}

	const char rkcommon_get_spl_hdr(struct image_tool_params params)
	{
	struct spl_info *info = rkcommon_get_spl_info(params->imagename);

	/*
	* info would not be NULL, because of we checked params before.
	*/
	return info->spl_hdr;
	}


	int rkcommon_get_spl_size(struct image_tool_params *params)
	{
	struct spl_info *info = rkcommon_get_spl_info(params->imagename);

	/*
	* info would not be NULL, because of we checked params before.
	*/
	return info->spl_size;
	}

	bool rkcommon_need_rc4_spl(struct image_tool_params *params)
	{
	struct spl_info *info = rkcommon_get_spl_info(params->imagename);

	/*
	* info would not be NULL, because of we checked params before.
	*/
	return info->spl_rc4;
	}

	bool rkcommon_spl_is_boot0(struct image_tool_params *params)
	{
	struct spl_info *info = rkcommon_get_spl_info(params->imagename);

	/*
	* info would not be NULL, because of we checked params before.
	*/
	return info->spl_boot0;
	}

	static void rkcommon_set_header0(void *buf, uint file_size,
	struct image_tool_params *params)
	{
	struct header0_info *hdr = buf;

	memset(buf, '\0', RK_INIT_OFFSET * RK_BLK_SIZE);
	hdr->signature = RK_SIGNATURE;
	hdr->disable_rc4 = !rkcommon_need_rc4_spl(params);
	hdr->init_offset = RK_INIT_OFFSET;

	hdr->init_size = DIV_ROUND_UP(file_size, RK_BLK_SIZE);
	/*
	* The init_size has to be a multiple of 4 blocks (i.e. of 2K)
	* or the BootROM will not boot the image.
	*
	* Note: To verify that this is not a legacy constraint, we
	* rechecked this against the RK3399 BootROM.
	*/
	hdr->init_size = ROUND(hdr->init_size, 4);
	/*
	* init_boot_size needs to be set, as it is read by the BootROM
	* to determine the size of the next-stage bootloader (e.g. U-Boot
	* proper), when used with the back-to-bootrom functionality.
	*
	* see https://lists.denx.de/pipermail/u-boot/2017-May/293267.html
	* for a more detailed explanation by Andy Yan
	*/
	hdr->init_boot_size = hdr->init_size + RK_MAX_BOOT_SIZE / RK_BLK_SIZE;

	rc4_encode(buf, RK_BLK_SIZE, rc4_key);
	}

	int rkcommon_set_header(void *buf, uint file_size,
	struct image_tool_params *params)
	{
	struct header1_info *hdr = buf + RK_SPL_HDR_START;

	if (file_size > rkcommon_get_spl_size(params))
	return -ENOSPC;

	rkcommon_set_header0(buf, file_size, params);

	/* Set up the SPL name (i.e. copy spl_hdr over) */
	memcpy(&hdr->magic, rkcommon_get_spl_hdr(params), RK_SPL_HDR_SIZE);

	if (rkcommon_need_rc4_spl(params))
	rkcommon_rc4_encode_spl(buf, RK_SPL_HDR_START,
	params->file_size - RK_SPL_HDR_START);

	return 0;
	}

	static inline unsigned rkcommon_offset_to_spi(unsigned offset)
	{
	/*
	* While SD/MMC images use a flat addressing, SPI images are padded
	* to use the first 2K of every 4K sector only.
	*/
	return ((offset & ~0x7ff) << 1) + (offset & 0x7ff);
	}

	static inline unsigned rkcommon_spi_to_offset(unsigned offset)
	{
	return ((offset & ~0x7ff) >> 1) + (offset & 0x7ff);
	}

	static int rkcommon_parse_header(const void buf, struct header0_info header0,
	struct spl_info **spl_info)
	{
	unsigned hdr1_offset;
	struct header1_info hdr1_sdmmc, hdr1_spi;
	int i;

	if (spl_info)
	*spl_info = NULL;

	/*
	* The first header (hdr0) is always RC4 encoded, so try to decrypt
	* with the well-known key.
	*/
	memcpy((void *)header0, buf, sizeof(struct header0_info));
	rc4_encode((void *)header0, sizeof(struct header0_info), rc4_key);

	if (header0->signature != RK_SIGNATURE)
	return -EPROTO;

	/* We don't support RC4 encoded image payloads here, yet... */
	if (header0->disable_rc4 == 0)
	return -ENOSYS;

	hdr1_offset = header0->init_offset * RK_BLK_SIZE;
	hdr1_sdmmc = (struct header1_info *)(buf + hdr1_offset);
	hdr1_spi = (struct header1_info *)(buf +
	rkcommon_offset_to_spi(hdr1_offset));

	for (i = 0; i < ARRAY_SIZE(spl_infos); i++) {
	if (!memcmp(&hdr1_sdmmc->magic, spl_infos[i].spl_hdr, 4)) {
	if (spl_info)
	*spl_info = &spl_infos[i];
	return IH_TYPE_RKSD;
	} else if (!memcmp(&hdr1_spi->magic, spl_infos[i].spl_hdr, 4)) {
	if (spl_info)
	*spl_info = &spl_infos[i];
	return IH_TYPE_RKSPI;
	}
	}

	return -1;
	}

	int rkcommon_verify_header(unsigned char *buf, int size,
	struct image_tool_params *params)
	{
	struct header0_info header0;
	struct spl_info img_spl_info, spl_info;
	int ret;

	ret = rkcommon_parse_header(buf, &header0, &img_spl_info);

	/* If this is the (unimplemented) RC4 case, then rewrite the result */
	if (ret == -ENOSYS)
	return 0;

	if (ret < 0)
	return ret;

	/*
	* If no 'imagename' is specified via the commandline (e.g. if this is
	* 'dumpimage -l' w/o any further constraints), we accept any spl_info.
	*/
	if (params->imagename == NULL)
	return 0;

	/* Match the 'imagename' against the 'spl_hdr' found */
	spl_info = rkcommon_get_spl_info(params->imagename);
	if (spl_info && img_spl_info)
	return strcmp(spl_info->spl_hdr, img_spl_info->spl_hdr);

	return -ENOENT;
	}

	void rkcommon_print_header(const void *buf)
	{
	struct header0_info header0;
	struct spl_info *spl_info;
	uint8_t image_type;
	int ret;

	ret = rkcommon_parse_header(buf, &header0, &spl_info);

	/* If this is the (unimplemented) RC4 case, then fail silently */
	if (ret == -ENOSYS)
	return;

	if (ret < 0) {
	fprintf(stderr, "Error: image verification failed\n");
	return;
	}

	image_type = ret;

	printf("Image Type: Rockchip %s (%s) boot image\n",
	spl_info->spl_hdr,
	(image_type == IH_TYPE_RKSD) ? "SD/MMC" : "SPI");
	printf("Data Size: %d bytes\n", header0.init_size * RK_BLK_SIZE);
	}

	void rkcommon_rc4_encode_spl(void *buf, unsigned int offset, unsigned int size)
	{
	unsigned int remaining = size;

	while (remaining > 0) {
	int step = (remaining > RK_BLK_SIZE) ? RK_BLK_SIZE : remaining;

	rc4_encode(buf + offset, step, rc4_key);
	offset += RK_BLK_SIZE;
	remaining -= step;
	}
	}

	int rkcommon_vrec_header(struct image_tool_params *params,
	struct image_type_params *tparams,
	unsigned int alignment)
	{
	unsigned int unpadded_size;
	unsigned int padded_size;

	/*
	* The SPL image looks as follows:
	*
	* 0x0 header0 (see rkcommon.c)
	* 0x800 spl_name ('RK30', ..., 'RK33')
	* (start of the payload for AArch64 payloads: we expect the
	* first 4 bytes to be available for overwriting with our
	* spl_name)
	* 0x804 first instruction to be executed
	* (start of the image/payload for 32bit payloads)
	*
	* For AArch64 (ARMv8) payloads, natural alignment (8-bytes) is
	* required for its sections (so the image we receive needs to
	* have the first 4 bytes reserved for the spl_name). Reserving
	* these 4 bytes is done using the BOOT0_HOOK infrastructure.
	*
	* Depending on this, the header is either 0x800 (if this is a
	* 'boot0'-style payload, which has reserved 4 bytes at the
	* beginning for the 'spl_name' and expects us to overwrite
	* its first 4 bytes) or 0x804 bytes in length.
	*/
	if (rkcommon_spl_is_boot0(params))
	tparams->header_size = RK_SPL_HDR_START;
	else
	tparams->header_size = RK_SPL_HDR_START + 4;

	/* Allocate, clear and install the header */
	tparams->hdr = malloc(tparams->header_size);
	if (!tparams->hdr)
	return -ENOMEM;
	memset(tparams->hdr, 0, tparams->header_size);

	/*
	* If someone passed in 0 for the alignment, we'd better handle
	* it correctly...
	*/
	if (!alignment)
	alignment = 1;

	unpadded_size = tparams->header_size + params->file_size;
	padded_size = ROUND(unpadded_size, alignment);

	return padded_size - unpadded_size;
	}