U-Boot

// SPDX-License-Identifier: GPL-2.0+
/*
 * (C) Copyright 2018 Arm Ltd.
 */

#include "imagetool.h"
#include <image.h>

#include <sunxi_image.h>

/*
 * NAND requires 8K padding. SD/eMMC gets away with 512 bytes,
 * but let's use the larger padding by default to cover both.
 */
#define PAD_SIZE			8192
#define PAD_SIZE_MIN			512

static int egon_get_arch(struct imgtool *itl)
{
	if (itl->Aflag)
		return itl->arch;

	/* For compatibility, assume ARM when no architecture specified */
	return IH_ARCH_ARM;
}

static int egon_check_params(struct imgtool *itl)
{
	/*
	 * Check whether the architecture is supported.
	 */
	switch (egon_get_arch(itl)) {
	case IH_ARCH_ARM:
	case IH_ARCH_RISCV:
		break;
	default:
		return EXIT_FAILURE;
	}

	/* We need a binary image file. */
	return !itl->dflag;
}

static int egon_verify_header(unsigned char *ptr, int image_size,
			      struct imgtool *itl)
{
	const struct boot_file_head *header = (void *)ptr;
	uint32_t length;

	/*
	 * First 4 bytes must be a branch instruction of the corresponding
	 * architecture.
	 */
	switch (egon_get_arch(itl)) {
	case IH_ARCH_ARM:
		if ((le32_to_cpu(header->b_instruction) & 0xff000000) != 0xea000000)
			return EXIT_FAILURE;
		break;
	case IH_ARCH_RISCV:
		if ((le32_to_cpu(header->b_instruction) & 0x00000fff) != 0x0000006f)
			return EXIT_FAILURE;
		break;
	default:
		return EXIT_FAILURE; /* Unknown architecture */
	}

	if (memcmp(header->magic, BOOT0_MAGIC, sizeof(header->magic)))
		return EXIT_FAILURE;

	length = le32_to_cpu(header->length);
	/* Must be at least 512 byte aligned. */
	if (length & 511)
		return EXIT_FAILURE;

	/*
	 * Image could also contain U-Boot proper, so could be bigger.
	 * But it must not be shorter.
	 */
	if (image_size < length)
		return EXIT_FAILURE;

	return EXIT_SUCCESS;
}

static void egon_print_header(const void *buf, struct imgtool *itl)
{
	const struct boot_file_head *header = buf;

	printf("Allwinner eGON image, size: %d bytes\n",
	       le32_to_cpu(header->length));

	if (memcmp(header->spl_signature, SPL_SIGNATURE, 3))
		return;

	printf("\tSPL header version %d.%d\n",
	       header->spl_signature[3] >> SPL_MINOR_BITS,
	       header->spl_signature[3] & ((1U << SPL_MINOR_BITS) - 1));
	if (header->spl_signature[3] >= SPL_DT_HEADER_VERSION) {
		uint32_t dt_name_offs = le32_to_cpu(header->dt_name_offset);

		if (dt_name_offs > 0)
			printf("\tDT name: %s\n", (char *)buf + dt_name_offs);
	}
}

static void egon_set_header(void *buf, struct stat *sbuf, int infd,
			    struct imgtool *itl)
{
	struct boot_file_head *header = buf;
	uint32_t *buf32 = buf;
	uint32_t checksum = 0, value;
	int i;

	/*
	 * Different architectures need different first instruction to
	 * branch to the body.
	 */
	switch (egon_get_arch(itl)) {
	case IH_ARCH_ARM:
		/* Generate an ARM branch instruction to jump over the header. */
		value = 0xea000000 | (sizeof(struct boot_file_head) / 4 - 2);
		header->b_instruction = cpu_to_le32(value);
		break;
	case IH_ARCH_RISCV:
		/*
		 * Generate a RISC-V JAL instruction with rd=x0
		 * (pseudo instruction J, jump without side effects).
		 *
		 * The following weird bit operation maps imm[20]
		 * to inst[31], imm[10:1] to inst[30:21],
		 * imm[11] to inst[20], imm[19:12] to inst[19:12],
		 * and imm[0] is dropped (because 1-byte RISC-V instruction
		 * is not allowed).
		 */
		value = 0x0000006f |
			((sizeof(struct boot_file_head) & 0x00100000) << 11) |
			((sizeof(struct boot_file_head) & 0x000007fe) << 20) |
			((sizeof(struct boot_file_head) & 0x00000800) << 9) |
			((sizeof(struct boot_file_head) & 0x000ff000) << 0);
		header->b_instruction = cpu_to_le32(value);
		break;
	}

	memcpy(header->magic, BOOT0_MAGIC, sizeof(header->magic));
	header->check_sum = cpu_to_le32(BROM_STAMP_VALUE);
	header->length = cpu_to_le32(itl->file_size);

	memcpy(header->spl_signature, SPL_SIGNATURE, 3);
	header->spl_signature[3] = SPL_ENV_HEADER_VERSION;

	/* If an image name has been provided, use it as the DT name. */
	if (itl->imagename && itl->imagename[0]) {
		if (strlen(itl->imagename) > sizeof(header->string_pool) - 1)
			printf("WARNING: DT name too long for SPL header!\n");
		else {
			strcpy((char *)header->string_pool, itl->imagename);
			value = offsetof(struct boot_file_head, string_pool);
			header->dt_name_offset = cpu_to_le32(value);
			header->spl_signature[3] = SPL_DT_HEADER_VERSION;
		}
	}

	/* Calculate the checksum. Yes, it's that simple. */
	for (i = 0; i < sbuf->st_size / 4; i++)
		checksum += le32_to_cpu(buf32[i]);
	header->check_sum = cpu_to_le32(checksum);
}

static int egon_check_image_type(uint8_t type)
{
	return type == IH_TYPE_SUNXI_EGON ? 0 : 1;
}

static int egon_vrec_header(struct imgtool *itl, struct imgtool_funcs *tparams)
{
	int pad_size = ALIGN(itl->bl_len ?: PAD_SIZE, PAD_SIZE_MIN);

	tparams->hdr = calloc(sizeof(struct boot_file_head), 1);

	/* Return padding to complete blocks. */
	return ALIGN(itl->file_size, pad_size) - itl->file_size;
}

U_BOOT_IMAGE_TYPE(
	sunxi_egon,
	"Allwinner eGON Boot Image support",
	sizeof(struct boot_file_head),
	NULL,
	egon_check_params,
	egon_verify_header,
	egon_print_header,
	egon_set_header,
	NULL,
	egon_check_image_type,
	NULL,
	egon_vrec_header
);