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dfu: mcuboot: add boot_read_bank_header()

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This is an accessor function for the MCUboot image header of an image
bank. The interface may seem a little cumbersome, but it is
future-proof against MCUboot feature and incompatible header version
changes.

Signed-off-by: Marti Bolivar <marti@opensourcefoundries.com>
This commit is contained in:
Marti Bolivar 2018-02-01 01:29:56 -05:00 • committed by Anas Nashif
commit e2c9be1a18
2 changed files with 195 additions and 4 deletions
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82
include/dfu/mcuboot.h
View file

@ -9,6 +9,88 @@
#define __MCUBOOT_H__ #define __MCUBOOT_H__
#include <stdbool.h> #include <stdbool.h>
#include <stddef.h>
#include <zephyr/types.h>
/**
* @brief MCUboot image header representation for image version
*
* The header for an MCUboot firmware image contains an embedded
* version number, in semantic versioning format. This structure
* represents the information it contains.
*/
struct mcuboot_img_sem_ver {
u8_t major;
u8_t minor;
u16_t revision;
u32_t build_num;
};
/**
* @brief Model for the MCUboot image header as of version 1
*
* This represents the data present in the image header, in version 1
* of the header format.
*
* Some information present in the header but not currently relevant
* to applications is omitted.
*/
struct mcuboot_img_header_v1 {
/** The size of the image, in bytes. */
u32_t image_size;
/** The image version. */
struct mcuboot_img_sem_ver sem_ver;
};
/**
* @brief Model for the MCUBoot image header
*
* This contains the decoded image header, along with the major
* version of MCUboot that the header was built for.
*
* (The MCUboot project guarantees that incompatible changes to the
* image header will result in major version changes to the bootloader
* itself, and will be detectable in the persistent representation of
* the header.)
*/
struct mcuboot_img_header {
/**
* The version of MCUboot the header is built for.
*
* The value 1 corresponds to MCUboot versions 1.x.y.
*/
u32_t mcuboot_version;
/**
* The header information. It is only valid to access fields
* in the union member corresponding to the mcuboot_version
* field above.
*/
union {
/** Header information for MCUboot version 1. */
struct mcuboot_img_header_v1 v1;
} h;
};
/**
* @brief Read the MCUboot image header information from an image bank.
*
* This attempts to parse the image header, which must begin at offset
* @a bank_offset from the beginning of the flash device used by
* MCUboot.
*
* @param bank_offset Offset of the image header from the start of the
* flash device used by MCUboot to store firmware.
* @param header On success, the returned header information is available
* in this structure.
* @param header_size Size of the header structure passed by the caller.
* If this is not large enough to contain all of the
* necessary information, an error is returned.
* @return Zero on success, a negative value on error.
*/
int boot_read_bank_header(u32_t bank_offset,
struct mcuboot_img_header *header,
size_t header_size);
/** /**
* @brief Check if the currently running image is confirmed as OK. * @brief Check if the currently running image is confirmed as OK.

117
subsys/dfu/boot/mcuboot.c
View file

@ -13,22 +13,51 @@
#include <init.h> #include <init.h>
#include <misc/__assert.h> #include <misc/__assert.h>
#include <misc/byteorder.h>
#include <board.h> #include <board.h>
#include <dfu/mcuboot.h> #include <dfu/mcuboot.h>
/* /*
* Helpers for image trailer, as defined by mcuboot. * Helpers for image headers and trailers, as defined by mcuboot.
*/ */
/* /*
* Strict defines: Defines in block below must be equal to coresponding * Strict defines: the definitions in the following block contain
* mcuboot defines * values which are MCUboot implementation requirements.
*/ */
/* Header: */
#define BOOT_HEADER_MAGIC_V1 0x96f3b83d
#define BOOT_HEADER_SIZE_V1 32
/* Trailer: */
#define BOOT_MAX_ALIGN 8 #define BOOT_MAX_ALIGN 8
#define BOOT_MAGIC_SZ 16 #define BOOT_MAGIC_SZ 16
#define BOOT_FLAG_SET 0x01 #define BOOT_FLAG_SET 0x01
#define BOOT_FLAG_UNSET 0xff #define BOOT_FLAG_UNSET 0xff
/* end_of Strict defines */
/*
* Raw (on-flash) representation of the v1 image header.
*/
struct mcuboot_v1_raw_header {
u32_t header_magic;
u32_t image_load_address;
u16_t header_size;
u16_t pad;
u32_t image_size;
u32_t image_flags;
struct {
u8_t major;
u8_t minor;
u16_t revision;
u32_t build_num;
} version;
u32_t pad2;
} __packed;
/*
* End of strict defines
*/
#define BOOT_MAGIC_GOOD 1 #define BOOT_MAGIC_GOOD 1
#define BOOT_MAGIC_BAD 2 #define BOOT_MAGIC_BAD 2
@ -156,6 +185,86 @@ static int boot_magic_write(u32_t bank_offs)
return rc; return rc;
} }
static int boot_read_v1_header(u32_t bank_offset,
struct mcuboot_v1_raw_header *v1_raw)
{
int rc;
/*
* Read and sanity-check the raw header.
*/
rc = flash_read(flash_dev, bank_offset, v1_raw, sizeof(*v1_raw));
if (rc) {
return rc;
}
v1_raw->header_magic = sys_le32_to_cpu(v1_raw->header_magic);
v1_raw->image_load_address =
sys_le32_to_cpu(v1_raw->image_load_address);
v1_raw->header_size = sys_le16_to_cpu(v1_raw->header_size);
v1_raw->image_size = sys_le32_to_cpu(v1_raw->image_size);
v1_raw->image_flags = sys_le32_to_cpu(v1_raw->image_flags);
v1_raw->version.revision =
sys_le16_to_cpu(v1_raw->version.revision);
v1_raw->version.build_num =
sys_le32_to_cpu(v1_raw->version.build_num);
/*
* Sanity checks.
*
* Larger values in header_size than BOOT_HEADER_SIZE_V1 are
* possible, e.g. if Zephyr was linked with
* CONFIG_TEXT_SECTION_OFFSET > BOOT_HEADER_SIZE_V1.
*/
if ((v1_raw->header_magic != BOOT_HEADER_MAGIC_V1) ||
(v1_raw->header_size < BOOT_HEADER_SIZE_V1)) {
return -EIO;
}
return 0;
}
int boot_read_bank_header(u32_t bank_offset,
struct mcuboot_img_header *header,
size_t header_size)
{
int rc;
struct mcuboot_v1_raw_header v1_raw;
struct mcuboot_img_sem_ver *sem_ver;
size_t v1_min_size = (sizeof(u32_t) +
sizeof(struct mcuboot_img_header_v1));
/*
* Only version 1 image headers are supported.
*/
if (header_size < v1_min_size) {
return -ENOMEM;
}
rc = boot_read_v1_header(bank_offset, &v1_raw);
if (rc) {
return rc;
}
/*
* Copy just the fields we care about into the return parameter.
*
* - header_magic: skip (only used to check format)
* - image_load_address: skip (only matters for PIC code)
* - header_size: skip (only used to check format)
* - image_size: include
* - image_flags: skip (all unsupported or not relevant)
* - version: include
*/
header->mcuboot_version = 1;
header->h.v1.image_size = v1_raw.image_size;
sem_ver = &header->h.v1.sem_ver;
sem_ver->major = v1_raw.version.major;
sem_ver->minor = v1_raw.version.minor;
sem_ver->revision = v1_raw.version.revision;
sem_ver->build_num = v1_raw.version.build_num;
return 0;
}
int boot_request_upgrade(int permanent) int boot_request_upgrade(int permanent)
{ {
int rc; int rc;