bl2/src/flash_map.c

/*
 * Copyright (c) 2019-2021, Arm Limited. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 *
 */

#include <stdbool.h>
#include "target.h"
#include "flash_map/flash_map.h"
#include "flash_map_backend/flash_map_backend.h"
#include "bootutil_priv.h"
#include "bootutil/bootutil_log.h"
#include "Driver_Flash.h"

#define FLASH_PROGRAM_UNIT    TFM_HAL_FLASH_PROGRAM_UNIT

/**
 * Return the greatest value not greater than `value` that is aligned to
 * `alignment`.
 */
#define FLOOR_ALIGN(value, alignment) ((value) & ~((alignment) - 1))

/**
 * Return the least value not less than `value` that is aligned to `alignment`.
 */
#define CEILING_ALIGN(value, alignment) \
                         (((value) + ((alignment) - 1)) & ~((alignment) - 1))

extern const struct flash_area flash_map[];
extern const int flash_map_entry_num;

/*
 * Check the target address in the flash_area_xxx operation.
 */
static bool is_range_valid(const struct flash_area *area,
                           uint32_t off,
                           uint32_t len)
{
    uint32_t size;

    if (!area) {
        return false;
    }

    if (!boot_u32_safe_add(&size, off, len)) {
        return false;
    }

    if (area->fa_size < size) {
        return false;
    }

    return true;
}

/*
 * `open` a flash area.  The `area` in this case is not the individual
 * sectors, but describes the particular flash area in question.
 */
int flash_area_open(uint8_t id, const struct flash_area **area)
{
    int i;

    BOOT_LOG_DBG("area %d", id);

    for (i = 0; i < flash_map_entry_num; i++) {
        if (id == flash_map[i].fa_id) {
            break;
        }
    }
    if (i == flash_map_entry_num) {
        return -1;
    }

    *area = &flash_map[i];
    return 0;
}

void flash_area_close(const struct flash_area *area)
{
    /* Nothing to do. */
}

/*
 * Read/write/erase. Offset is relative from beginning of flash area.
 * `off` and `len` can be any alignment.
 * Return 0 on success, other value on failure.
 */
int flash_area_read(const struct flash_area *area, uint32_t off, void *dst,
                    uint32_t len)
{
    uint32_t remaining_len;
    uint32_t aligned_off;
    uint8_t temp_buffer[sizeof(uint32_t)];
    uint8_t align_unit, i = 0;
    int ret;

    /* Valid entries for data item width */
    uint32_t data_width_byte[] = {
        sizeof(uint8_t),
        sizeof(uint16_t),
        sizeof(uint32_t),
    };
    ARM_FLASH_CAPABILITIES DriverCapabilities;

    BOOT_LOG_DBG("read area=%d, off=%#x, len=%#x", area->fa_id, off, len);

    if (!is_range_valid(area, off, len)) {
        return -1;
    }
    remaining_len = len;

    /* CMSIS ARM_FLASH_ReadData API requires the `addr` data type size aligned.
     * Data type size is specified by the data_width in ARM_FLASH_CAPABILITIES.
     */
    DriverCapabilities = DRV_FLASH_AREA(area)->GetCapabilities();
    align_unit = data_width_byte[DriverCapabilities.data_width];
    aligned_off = FLOOR_ALIGN(off, align_unit);

    /* Read the first align_unit long data if `off` is not aligned. */
    if (aligned_off != off) {
        ret = DRV_FLASH_AREA(area)->ReadData(area->fa_off + aligned_off,
                                             temp_buffer,
                                             align_unit);
        if (ret < 0) {
            return ret;
        }

        /* Copy the read data from off. */
        for (i = 0; i + off - aligned_off < align_unit; i++) {
            ((uint8_t *)dst)[i] = temp_buffer[i + off - aligned_off];
        }
        remaining_len -= align_unit - (off - aligned_off);
    }

    /* CMSIS ARM_FLASH_ReadData does not require the alignment of `cnt`.*/
    if (remaining_len) {
        ret = DRV_FLASH_AREA(area)->ReadData(area->fa_off + off + i,
                                             (uint8_t *)dst + i,
                                             remaining_len);
    }

    /* CMSIS ARM_FLASH_ReadData can return the number of data items read or
     * Status Error Codes which are negative for failures.
     */
    if (ret < 0) {
        return ret;
    } else {
        return 0;
    }
}

/* Writes `len` bytes of flash memory at `off` from the buffer at `src`.
 * `off` and `len` can be any alignment.
 */
int flash_area_write(const struct flash_area *area, uint32_t off,
                     const void *src, uint32_t len)
{
    uint8_t add_padding[FLASH_PROGRAM_UNIT];
    uint8_t len_padding[FLASH_PROGRAM_UNIT - 1];

    /* The PROGRAM_UNIT aligned value of `off` */
    uint32_t aligned_off;

    /* The total write length. */
    uint32_t aligned_len;
    uint32_t i, k;

    /* The index in src[] that has been programmed. */
    uint32_t src_written_idx = 0;
    uint32_t add_padding_size, len_padding_size;
    uint32_t write_size;
    uint32_t last_unit_start_off = 0;
    /*
     *    aligned_off           off           last_unit_start_off
     *        |                  |                     |
     *        | add_padding_size |                     |   | len_padding_size  |
     *        |+++++++++++++++++++**|******************|***@@@@@@@@@@@@@@@@@@@@|
     *        |                     |                  |                       |
     * ---->--|---- PROGRAM UNIT ---|-- PROGRAM UNIT --|---- PROGRAM UNIT -----|
     *        |                     |                  |                       |
     *        |+++++++++++++++++++**|******************|***@@@@@@@@@@@@@@@@@@@@|
     *                            |<-------- len --------->|
     */

    BOOT_LOG_DBG("write area=%d, off=%#x, len=%#x", area->fa_id, off, len);

    /* Align the target address. The area->fa_off should already be aligned. */
    aligned_off = FLOOR_ALIGN(off, FLASH_PROGRAM_UNIT);
    add_padding_size = off - aligned_off;
    if (!is_range_valid(area, off, len)) {
        return -1;
    }

    /* Read the bytes from aligned_off to off. */
    if (flash_area_read(area, aligned_off, add_padding, add_padding_size)) {
        return -1;
    }

    /* Align the write size */
    aligned_len = CEILING_ALIGN(len + add_padding_size, FLASH_PROGRAM_UNIT);
    len_padding_size = aligned_len - len - add_padding_size;
    if (!is_range_valid(area, aligned_off, aligned_len)) {
        return -1;
    }

    /* Read the bytes from (off + len) to (off + aligned_len). */
    if (flash_area_read(area, off + len, len_padding,
                        len_padding_size)) {
        return -1;
    }

    /* Program the first FLASH_PROGRAM_UNIT. */
    if (add_padding_size) {
        /* Fill the first program unit bytes with data from src. */
        for (i = add_padding_size, src_written_idx = 0;
             i < FLASH_PROGRAM_UNIT && src_written_idx < len;
             i++, src_written_idx++) {
            add_padding[i] = ((uint8_t *)src)[src_written_idx];
        }
        if (src_written_idx == len) {
            /* aligned_len equals to FLASH_PROGRAM_UNIT in this case.
             * Fill the len_padding_size datas into add_padding.
             */
            for (k = 0; i < FLASH_PROGRAM_UNIT && k < len_padding_size;
                 i++, k++) {
                add_padding[i] = len_padding[k];
            }
            if (k != len_padding_size) {
                return -1;
            }
        }

        /* Check the first program unit bytes are all filled. */
        if (i != FLASH_PROGRAM_UNIT) {
            return -1;
        }
        if (DRV_FLASH_AREA(area)->ProgramData(area->fa_off + aligned_off,
                                              add_padding,
                                              FLASH_PROGRAM_UNIT)) {
            return -1;
        }
    }

    /* 'src_written_idx' indicates the number of the src data which has already
     * been programed into flash. 'src_written_idx' equals to 'len' means that
     * all the data in src has been programmed and aligned_len equals to
     * FLASH_PROGRAM_UNIT. This case has been handled above.
     * 'src_written_idx' less than 'len' means that not all the data in src has
     * been programmed.
     */
    if (src_written_idx < len) {
        /* Program from the first aligned bytes(src_written_idx) to the last
         * aligned bytes in src.
         */
        write_size = FLOOR_ALIGN(len - src_written_idx, FLASH_PROGRAM_UNIT);
        if (write_size > 0) {
            if (DRV_FLASH_AREA(area)->ProgramData(
                                           area->fa_off + off + src_written_idx,
                                           src,
                                           write_size)) {
                return -1;
            }
            src_written_idx += write_size;
        }
        last_unit_start_off = src_written_idx;

        /* Program the last program unit data into flash. */
        if (len_padding_size) {
            /* Copy the last unaligned bytes in src to add_padding. */
            for (i = 0; i < FLASH_PROGRAM_UNIT && src_written_idx < len;
                 i++, src_written_idx++) {
                add_padding[i] = ((uint8_t *)src)[src_written_idx];
            }

            if (src_written_idx != len) {
                return -1;
            }
            /* Copy the len_padding_size bytes in len_padding to add_padding. */
            for (k = 0; i < FLASH_PROGRAM_UNIT && k < len_padding_size;
                 i++, k++) {
                add_padding[i] = len_padding[k];
            }
            write_size = add_padding_size + last_unit_start_off +
                         FLASH_PROGRAM_UNIT;
            if (i != FLASH_PROGRAM_UNIT || k != len_padding_size ||
                aligned_len != write_size) {
                return -1;
            }
            if (DRV_FLASH_AREA(area)->ProgramData(
                                area->fa_off + off + last_unit_start_off,
                                add_padding,
                                FLASH_PROGRAM_UNIT)) {
                return -1;
            }
        }
    }

    return 0;
}

int flash_area_erase(const struct flash_area *area, uint32_t off, uint32_t len)
{
    ARM_FLASH_INFO *flash_info;
    uint32_t deleted_len = 0;
    int32_t rc = 0;

    BOOT_LOG_DBG("erase area=%d, off=%#x, len=%#x", area->fa_id, off, len);

    if (!is_range_valid(area, off, len)) {
        return -1;
    }

    flash_info = DRV_FLASH_AREA(area)->GetInfo();

    if (flash_info->sector_info == NULL) {
        /* Uniform sector layout */
        while (deleted_len < len) {
            rc = DRV_FLASH_AREA(area)->EraseSector(area->fa_off + off);
            if (rc != 0) {
                break;
            }
            deleted_len += flash_info->sector_size;
            off         += flash_info->sector_size;
        }
    } else {
        /* Inhomogeneous sector layout, explicitly defined
         * Currently not supported.
         */
    }

    return rc;
}

uint32_t flash_area_align(const struct flash_area *area)
{
    ARM_FLASH_INFO *flash_info;

    flash_info = DRV_FLASH_AREA(area)->GetInfo();
    return flash_info->program_unit;
}