Re: [RFC PATCH 01/11] scripts: Add Allwinner eGON image support

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

On 11.05.23 01:37, Jules Maselbas wrote:
> On power-up Allwinner SoC starts in boot ROM, aka BROM, which will search
> for an eGON image: first from the SD card, then from eMMC. If no image is
> found then the BROM will enter into FEL mode that can be used for initial
> programming and recovery of devices using USB.
> 
> The eGON header structure is adapted from u-boot: /include/sunxi_image.h,
> the header structure is also documented on https://linux-sunxi.org/EGON
> 
> BROM will load, at most, the first 32KB of the image into SRAM, including
> the header itself! The jump instruction in the header needs to be patched
> accordingly with the image size.

S-o-b missing.

> ---
>  arch/arm/mach-sunxi/egon_header.c |  11 +++
>  include/mach/sunxi/egon.h         |  63 ++++++++++++++++
>  scripts/Kconfig                   |   7 ++
>  scripts/Makefile                  |   1 +
>  scripts/egon_mkimage.c            | 115 ++++++++++++++++++++++++++++++
>  5 files changed, 197 insertions(+)
>  create mode 100644 arch/arm/mach-sunxi/egon_header.c
>  create mode 100644 include/mach/sunxi/egon.h
>  create mode 100644 scripts/egon_mkimage.c
> 
> diff --git a/arch/arm/mach-sunxi/egon_header.c b/arch/arm/mach-sunxi/egon_header.c
> new file mode 100644
> index 0000000000..9a4822f71d
> --- /dev/null
> +++ b/arch/arm/mach-sunxi/egon_header.c
> @@ -0,0 +1,11 @@
> +#include <common.h>
> +#include <mach/sunxi/egon.h>
> +#if 0

Dead code

> +const struct egon_header sunxi_egon_header
> +__attribute__((section(".text_egon_header"))) = {
> +	 /* put a valid arm32 jump over the header, in order for images to
> +	  * to work when not loaded by boot rom but by the FEL */
> +	.branch = EGON_HDR_BRANCH,
> +	.magic = "eGON",
> +};
> +#endif
> diff --git a/include/mach/sunxi/egon.h b/include/mach/sunxi/egon.h
> new file mode 100644
> index 0000000000..f70730ee25
> --- /dev/null
> +++ b/include/mach/sunxi/egon.h
> @@ -0,0 +1,63 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +
> +#ifndef SUNIX_EGON
> +#define SUNIX_EGON
> +
> +struct egon_header {
> +	uint32_t branch; /* branch instruction to jump over the header */
> +	uint8_t magic[8]; /* "eGON.BT0" or "eGON.BT1" */
> +	uint32_t check_sum;
> +	uint32_t length;
> +	/*
> +	 * We use a simplified header, only filling in what is needed
> +	 * by the boot ROM. To be compatible with Allwinner tools we
> +	 * would need to implement the proper fields here instead of
> +	 * padding.
> +	 *
> +	 * Actually we want the ability to recognize our "sunxi" variant
> +	 * of the SPL. To do so, let's place a special signature into the
> +	 * "pub_head_size" field. We can reasonably expect Allwinner's
> +	 * boot0 to always have the upper 16 bits of this set to 0 (after
> +	 * all the value shouldn't be larger than the limit imposed by
> +	 * SRAM size).
> +	 * If the signature is present (at 0x14), then we know it's safe
> +	 * to use the remaining 8 bytes (at 0x18) for our own purposes.
> +	 * (E.g. sunxi-tools "fel" utility can pass information there.)
> +	 */
> +	union {
> +		uint32_t header_size;
> +		uint8_t spl_signature[4];
> +	};
> +	uint32_t fel_script_address;/* since v0.1, set by sunxi-fel */
> +	/*
> +	 * If the fel_uEnv_length member below is set to a non-zero value,
> +	 * it specifies the size (byte count) of data at fel_script_address.
> +	 * At the same time this indicates that the data is in uEnv.txt
> +	 * compatible format, ready to be imported via "env import -t".
> +	 */
> +	uint32_t fel_uEnv_length;/* since v0.1, set by sunxi-fel */
> +	/*
> +	 * Offset of an ASCIIZ string (relative to the SPL header), which
> +	 * contains the default device tree name (CONFIG_DEFAULT_DEVICE_TREE).
> +	 * This is optional and may be set to NULL. Is intended to be used
> +	 * by flash programming tools for providing nice informative messages
> +	 * to the users.
> +	 */
> +	uint32_t dt_name_offset;/* since v0.2, set by mksunxiboot */
> +	uint32_t dram_size;/* in MiB, since v0.3, set by SPL */
> +	uint32_t boot_media;/* written here by the boot ROM */
> +	/* A padding area (may be used for storing text strings) */
> +	uint32_t string_pool[13];/* since v0.2, filled by mksunxiboot */
> +	/* The header must be a multiple of 32 bytes (for VBAR alignment) */
> +	/* And at least 64 byte (https://patchwork.ozlabs.org/patch/622173) */
> +};
> +#define EGON_HDR_BRANCH (0xea000000 | (sizeof(struct egon_header) / 4 - 2))
> +#define sunxi_egon_header()						\
> +	{								\
> +		static const struct egon_header _hdr			\
> +			__attribute__((section(".text_head_egon_header"))) = \
> +			{ .branch = EGON_HDR_BRANCH, .magic = "eGON" };	\
> +		__keep_symbolref(_hdr);					\
> +	}
> +
> +#endif
> diff --git a/scripts/Kconfig b/scripts/Kconfig
> index dcd5f32d1d..7517f5b79f 100644
> --- a/scripts/Kconfig
> +++ b/scripts/Kconfig
> @@ -56,6 +56,13 @@ config RK_IMAGE
>  	help
>  	  This enables building the image creation tool for Rockchip SoCs
>  
> +config EGON_IMAGE
> +       bool "Allwinner eGON image tool" if COMPILE_HOST_TOOLS
> +       depends on ARCH_SUNXI || COMPILE_HOST_TOOLS
> +       default y if ARCH_SUNXI
> +       help
> +         This enables building the image creation tool for Allwinner sunxi SoCs
> +
>  config OMAP_IMAGE
>  	bool "TI OMAP image tools" if COMPILE_HOST_TOOLS
>  	depends on ARCH_OMAP || COMPILE_HOST_TOOLS
> diff --git a/scripts/Makefile b/scripts/Makefile
> index 72ad9ad7a6..13e80db7af 100644
> --- a/scripts/Makefile
> +++ b/scripts/Makefile
> @@ -28,6 +28,7 @@ hostprogs-always-$(CONFIG_LAYERSCAPE_PBLIMAGE)		+= pblimage
>  hostprogs-always-$(CONFIG_STM32_IMAGE)			+= stm32image
>  hostprogs-always-$(CONFIG_RISCV)			+= prelink-riscv
>  hostprogs-always-$(CONFIG_RK_IMAGE)			+= rkimage
> +hostprogs-always-$(CONFIG_EGON_IMAGE)			+= egon_mkimage
>  HOSTCFLAGS_rkimage = `pkg-config --cflags openssl`
>  HOSTLDLIBS_rkimage = `pkg-config --libs openssl`
>  KBUILD_HOSTCFLAGS += -I$(srctree)/scripts/include/
> diff --git a/scripts/egon_mkimage.c b/scripts/egon_mkimage.c
> new file mode 100644
> index 0000000000..887caa29f0
> --- /dev/null
> +++ b/scripts/egon_mkimage.c
> @@ -0,0 +1,115 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +
> +#include <stdio.h>
> +#include <errno.h>
> +#include <stdlib.h>
> +#include <stdint.h>
> +#include <string.h>
> +
> +#include "../include/mach/sunxi/egon.h"
> +
> +#include "compiler.h"
> +#include "common.h"
> +#include "common.c"
> +
> +#define ALIGN(x, a)		__ALIGN_MASK(x, (typeof(x))(a) - 1)
> +#define __ALIGN_MASK(x, mask)	(((x) + (mask)) & ~(mask))
> +#define STAMP_VALUE 0x5f0a6c39
> +
> +static void mkimage(char *infile, char *outfile)
> +{
> +	struct egon_header *hdr;
> +	uint32_t *p32;
> +	uint32_t sum;
> +	int i;
> +	size_t hdr_size;
> +	size_t bin_size;
> +	size_t img_size;
> +	char *bin;
> +	int fd, ret;
> +
> +	bin = read_file(infile, &bin_size);
> +	if (!bin) {
> +		perror("read_file");
> +		exit(1);
> +	}
> +
> +	/* the header must be a multiple of 32 bytes */
> +	hdr_size = sizeof(*hdr);
> +
> +	/* test if the binary has reserved space for the header */
> +	hdr = (void *)bin;
> +	if (hdr->branch == EGON_HDR_BRANCH && memcmp(hdr->magic, "eGON", 4) == 0) {
> +		/* strip the existing header */
> +		bin += hdr_size;
> +		bin_size -= hdr_size;
> +	}
> +	hdr = calloc(1, hdr_size);
> +	if (!hdr) {
> +		perror("malloc");
> +		exit(1);
> +	}
> +
> +	/* The total image length must be a multiple of 4K bytes */
> +	img_size = ALIGN(hdr_size + bin_size, 4096);
> +
> +	hdr->check_sum = 0;
> +	hdr->branch = EGON_HDR_BRANCH;
> +	hdr->length = cpu_to_le32(img_size);
> +	memcpy(hdr->magic, "eGON.BT0", 8);
> +	memcpy(hdr->spl_signature, "SPL", 3);
> +	hdr->spl_signature[3] = 0x03; /* version 0.3 */
> +
> +	/* calculate the checksum */
> +	sum = STAMP_VALUE;
> +	for (p32 = (void *) hdr, i = 0; i < hdr_size / sizeof(uint32_t); i++)
> +		sum += le32_to_cpu(p32[i]);
> +	for (p32 = (void *) bin, i = 0; i < bin_size / sizeof(uint32_t); i++)
> +		sum += le32_to_cpu(p32[i]);
> +	hdr->check_sum = cpu_to_le32(sum);
> +
> +	fd = open(outfile, O_WRONLY | O_TRUNC | O_CREAT,
> +		  S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
> +	if (fd < 0) {
> +		fprintf(stderr, "Cannot open %s: %s\n", outfile, strerror(errno));
> +		exit(1);
> +	}
> +	/* write the header */
> +	ret = write_full(fd, hdr, hdr_size);
> +	if (ret < 0) {
> +		perror("write_full");
> +		exit(1);
> +	}
> +	/* write the binary */
> +	ret = write_full(fd, bin, bin_size);
> +	if (ret < 0) {
> +		perror("write_full");
> +		exit(1);
> +	}
> +	/* align the image */
> +	ret = ftruncate(fd, img_size);
> +	if (ret < 0) {
> +		perror("ftruncate");
> +		exit(1);
> +	}
> +	close(fd);
> +
> +	free(hdr);
> +}
> +
> +static void usage(char *argv0)
> +{
> +	fprintf(stderr, "usage: %s <infile> <outfile>\n", argv0);
> +}
> +
> +int main(int argc, char *argv[])
> +{
> +	if (argc != 3) {
> +		usage(argv[0]);
> +		return 1;
> +	}
> +
> +	mkimage(argv[1], argv[2]);
> +
> +	return 0;
> +}

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