flash/nor/core.c

Go to the documentation of this file.

// SPDX-License-Identifier: GPL-2.0-or-later
 
/***************************************************************************
 *   Copyright (C) 2005 by Dominic Rath <Dominic.Rath@gmx.de>              *
 *   Copyright (C) 2007-2010 Øyvind Harboe <oyvind.harboe@zylin.com>       *
 *   Copyright (C) 2008 by Spencer Oliver <spen@spen-soft.co.uk>           *
 *   Copyright (C) 2009 Zachary T Welch <zw@superlucidity.net>             *
 *   Copyright (C) 2010 by Antonio Borneo <borneo.antonio@gmail.com>       *
 *   Copyright (C) 2017-2018 Tomas Vanek <vanekt@fbl.cz>                   *
 ***************************************************************************/
 
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <flash/common.h>
#include <flash/nor/core.h>
#include <flash/nor/imp.h>
#include <target/image.h>
 
static struct flash_bank *flash_banks;
 
int flash_driver_erase(struct flash_bank *bank, unsigned int first,
        unsigned int last)
{
    int retval;
 
    retval = bank->driver->erase(bank, first, last);
    if (retval != ERROR_OK)
        LOG_ERROR("failed erasing sectors %u to %u", first, last);
 
    return retval;
}
 
int flash_driver_protect(struct flash_bank *bank, int set, unsigned int first,
        unsigned int last)
{
    int retval;
    unsigned int num_blocks;
 
    if (!bank->driver->protect) {
        LOG_ERROR("Flash protection is not supported");
        return ERROR_FLASH_OPER_UNSUPPORTED;
    }
 
    if (bank->num_prot_blocks)
        num_blocks = bank->num_prot_blocks;
    else
        num_blocks = bank->num_sectors;
 
 
    /* callers may not supply illegal parameters ... */
    if (first > last || last >= num_blocks) {
        LOG_ERROR("illegal protection block range");
        return ERROR_FAIL;
    }
 
    /* force "set" to 0/1 */
    set = !!set;
 
    /* DANGER!
     *
     * We must not use any cached information about protection state!!!!
     *
     * There are a million things that could change the protect state:
     *
     * the target could have reset, power cycled, been hot plugged,
     * the application could have run, etc.
     *
     * Drivers only receive valid protection block range.
     */
    retval = bank->driver->protect(bank, set, first, last);
    if (retval != ERROR_OK)
        LOG_ERROR("failed setting protection for blocks %u to %u", first, last);
 
    return retval;
}
 
int flash_driver_write(struct flash_bank *bank,
    const uint8_t *buffer, uint32_t offset, uint32_t count)
{
    int retval;
 
    retval = bank->driver->write(bank, buffer, offset, count);
    if (retval != ERROR_OK) {
        LOG_ERROR(
            "error writing to flash at address " TARGET_ADDR_FMT
            " at offset 0x%8.8" PRIx32,
            bank->base,
            offset);
    }
 
    return retval;
}
 
int flash_driver_read(struct flash_bank *bank,
    uint8_t *buffer, uint32_t offset, uint32_t count)
{
    int retval;
 
    LOG_DEBUG("call flash_driver_read()");
 
    retval = bank->driver->read(bank, buffer, offset, count);
    if (retval != ERROR_OK) {
        LOG_ERROR(
            "error reading to flash at address " TARGET_ADDR_FMT
            " at offset 0x%8.8" PRIx32,
            bank->base,
            offset);
    }
 
    return retval;
}
 
int default_flash_read(struct flash_bank *bank,
    uint8_t *buffer, uint32_t offset, uint32_t count)
{
    return target_read_buffer(bank->target, offset + bank->base, count, buffer);
}
 
int flash_driver_verify(struct flash_bank *bank,
    const uint8_t *buffer, uint32_t offset, uint32_t count)
{
    int retval;
 
    retval = bank->driver->verify ? bank->driver->verify(bank, buffer, offset, count) :
        default_flash_verify(bank, buffer, offset, count);
    if (retval != ERROR_OK) {
        LOG_ERROR("verify failed in bank at " TARGET_ADDR_FMT " starting at 0x%8.8" PRIx32,
            bank->base, offset);
    }
 
    return retval;
}
 
int default_flash_verify(struct flash_bank *bank,
    const uint8_t *buffer, uint32_t offset, uint32_t count)
{
    uint32_t target_crc, image_crc;
    int retval;
 
    retval = image_calculate_checksum(buffer, count, &image_crc);
    if (retval != ERROR_OK)
        return retval;
 
    retval = target_checksum_memory(bank->target, offset + bank->base, count, &target_crc);
    if (retval != ERROR_OK)
        return retval;
 
    LOG_DEBUG("addr " TARGET_ADDR_FMT ", len 0x%08" PRIx32 ", crc 0x%08" PRIx32 " 0x%08" PRIx32,
        offset + bank->base, count, ~image_crc, ~target_crc);
    if (target_crc == image_crc)
        return ERROR_OK;
    else
        return ERROR_FAIL;
}
 
void flash_bank_add(struct flash_bank *bank)
{
    /* put flash bank in linked list */
    unsigned int bank_num = 0;
    if (flash_banks) {
        /* find last flash bank */
        struct flash_bank *p = flash_banks;
        while (p->next) {
            bank_num += 1;
            p = p->next;
        }
        p->next = bank;
        bank_num += 1;
    } else
        flash_banks = bank;
 
    bank->bank_number = bank_num;
}
 
struct flash_bank *flash_bank_list(void)
{
    return flash_banks;
}
 
struct flash_bank *get_flash_bank_by_num_noprobe(unsigned int num)
{
    struct flash_bank *p;
    unsigned int i = 0;
 
    for (p = flash_banks; p; p = p->next) {
        if (i++ == num)
            return p;
    }
    LOG_ERROR("flash bank %d does not exist", num);
    return NULL;
}
 
unsigned int flash_get_bank_count(void)
{
    struct flash_bank *p;
    unsigned int i = 0;
    for (p = flash_banks; p; p = p->next)
        i++;
    return i;
}
 
void default_flash_free_driver_priv(struct flash_bank *bank)
{
    free(bank->driver_priv);
    bank->driver_priv = NULL;
}
 
void flash_free_all_banks(void)
{
    struct flash_bank *bank = flash_banks;
    while (bank) {
        struct flash_bank *next = bank->next;
        if (bank->driver->free_driver_priv)
            bank->driver->free_driver_priv(bank);
        else
            LOG_WARNING("Flash driver of %s does not support free_driver_priv()", bank->name);
 
        free(bank->sectors);
        free(bank->prot_blocks);
 
        free(bank->name);
        free(bank);
        bank = next;
    }
    flash_banks = NULL;
}
 
struct flash_bank *get_flash_bank_by_name_noprobe(const char *name)
{
    unsigned int requested = get_flash_name_index(name);
    unsigned int found = 0;
 
    struct flash_bank *bank;
    for (bank = flash_banks; bank; bank = bank->next) {
        if (strcmp(bank->name, name) == 0)
            return bank;
        if (!flash_driver_name_matches(bank->driver->name, name))
            continue;
        if (++found < requested)
            continue;
        return bank;
    }
    return NULL;
}
 
int get_flash_bank_by_name(const char *name, struct flash_bank **bank_result)
{
    struct flash_bank *bank;
    int retval;
 
    bank = get_flash_bank_by_name_noprobe(name);
    if (bank) {
        retval = bank->driver->auto_probe(bank);
 
        if (retval != ERROR_OK) {
            LOG_ERROR("auto_probe failed");
            return retval;
        }
    }
 
    *bank_result = bank;
    return ERROR_OK;
}
 
int get_flash_bank_by_num(unsigned int num, struct flash_bank **bank)
{
    struct flash_bank *p = get_flash_bank_by_num_noprobe(num);
    int retval;
 
    if (!p)
        return ERROR_FAIL;
 
    retval = p->driver->auto_probe(p);
 
    if (retval != ERROR_OK) {
        LOG_ERROR("auto_probe failed");
        return retval;
    }
    *bank = p;
    return ERROR_OK;
}
 
/* lookup flash bank by address, bank not found is success, but
 * result_bank is set to NULL. */
int get_flash_bank_by_addr(struct target *target,
    target_addr_t addr,
    bool check,
    struct flash_bank **result_bank)
{
    struct flash_bank *c;
 
    /* cycle through bank list */
    for (c = flash_banks; c; c = c->next) {
        if (c->target != target)
            continue;
 
        int retval;
        retval = c->driver->auto_probe(c);
 
        if (retval != ERROR_OK) {
            LOG_ERROR("auto_probe failed");
            return retval;
        }
        /* check whether address belongs to this flash bank */
        if ((addr >= c->base) && (addr <= c->base + (c->size - 1))) {
            *result_bank = c;
            return ERROR_OK;
        }
    }
    *result_bank = NULL;
    if (check) {
        LOG_ERROR("No flash at address " TARGET_ADDR_FMT, addr);
        return ERROR_FAIL;
    }
    return ERROR_OK;
}
 
static int default_flash_mem_blank_check(struct flash_bank *bank)
{
    struct target *target = bank->target;
    const int buffer_size = 1024;
    uint32_t n_bytes;
    int retval = ERROR_OK;
 
    if (bank->target->state != TARGET_HALTED) {
        LOG_ERROR("Target not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    uint8_t *buffer = malloc(buffer_size);
 
    for (unsigned int i = 0; i < bank->num_sectors; i++) {
        uint32_t j;
        bank->sectors[i].is_erased = 1;
 
        for (j = 0; j < bank->sectors[i].size; j += buffer_size) {
            uint32_t chunk;
            chunk = buffer_size;
            if (chunk > (bank->sectors[i].size - j))
                chunk = (bank->sectors[i].size - j);
 
            retval = target_read_memory(target,
                    bank->base + bank->sectors[i].offset + j,
                    4,
                    chunk/4,
                    buffer);
            if (retval != ERROR_OK)
                goto done;
 
            for (n_bytes = 0; n_bytes < chunk; n_bytes++) {
                if (buffer[n_bytes] != bank->erased_value) {
                    bank->sectors[i].is_erased = 0;
                    break;
                }
            }
        }
    }
 
done:
    free(buffer);
 
    return retval;
}
 
int default_flash_blank_check(struct flash_bank *bank)
{
    struct target *target = bank->target;
    int retval;
 
    if (bank->target->state != TARGET_HALTED) {
        LOG_ERROR("Target not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    struct target_memory_check_block *block_array;
    block_array = malloc(bank->num_sectors * sizeof(struct target_memory_check_block));
    if (!block_array)
        return default_flash_mem_blank_check(bank);
 
    for (unsigned int i = 0; i < bank->num_sectors; i++) {
        block_array[i].address = bank->base + bank->sectors[i].offset;
        block_array[i].size = bank->sectors[i].size;
        block_array[i].result = UINT32_MAX; /* erase state unknown */
    }
 
    bool fast_check = true;
    for (unsigned int i = 0; i < bank->num_sectors; ) {
        unsigned int checked;
        retval = target_blank_check_memory(target,
                block_array + i, bank->num_sectors - i,
                bank->erased_value, &checked);
        if (retval != ERROR_OK) {
            /* Run slow fallback if the first run gives no result
             * otherwise use possibly incomplete results */
            if (i == 0)
                fast_check = false;
            break;
        }
        i += checked; /* add number of blocks done this round */
    }
 
    if (fast_check) {
        for (unsigned int i = 0; i < bank->num_sectors; i++)
            bank->sectors[i].is_erased = block_array[i].result;
        retval = ERROR_OK;
    } else {
        if (retval == ERROR_NOT_IMPLEMENTED)
            LOG_USER("Running slow fallback erase check");
        else
            LOG_USER("Running slow fallback erase check - add working memory");
 
        retval = default_flash_mem_blank_check(bank);
    }
    free(block_array);
 
    return retval;
}
 
/* Manipulate given flash region, selecting the bank according to target
 * and address.  Maps an address range to a set of sectors, and issues
 * the callback() on that set ... e.g. to erase or unprotect its members.
 *
 * Parameter iterate_protect_blocks switches iteration of protect block
 * instead of erase sectors. If there is no protect blocks array, sectors
 * are used in iteration, so compatibility for old flash drivers is retained.
 *
 * The "pad_reason" parameter is a kind of boolean:  when it's NULL, the
 * range must fit those sectors exactly.  This is clearly safe; it can't
 * erase data which the caller said to leave alone, for example.  If it's
 * non-NULL, rather than failing, extra data in the first and/or last
 * sectors will be added to the range, and that reason string is used when
 * warning about those additions.
 */
static int flash_iterate_address_range_inner(struct target *target,
    char *pad_reason, target_addr_t addr, uint32_t length,
    bool iterate_protect_blocks,
    int (*callback)(struct flash_bank *bank, unsigned int first,
        unsigned int last))
{
    struct flash_bank *c;
    struct flash_sector *block_array;
    target_addr_t last_addr = addr + length - 1;    /* the last address of range */
    int first = -1;
    int last = -1;
    int i;
    int num_blocks;
 
    int retval = get_flash_bank_by_addr(target, addr, true, &c);
    if (retval != ERROR_OK)
        return retval;
 
    if (c->size == 0 || c->num_sectors == 0) {
        LOG_ERROR("Bank is invalid");
        return ERROR_FLASH_BANK_INVALID;
    }
 
    if (length == 0) {
        /* special case, erase whole bank when length is zero */
        if (addr != c->base) {
            LOG_ERROR("Whole bank access must start at beginning of bank.");
            return ERROR_FLASH_DST_BREAKS_ALIGNMENT;
        }
 
        return callback(c, 0, c->num_sectors - 1);
    }
 
    /* check whether it all fits in this bank */
    if (last_addr > c->base + c->size - 1) {
        LOG_ERROR("Flash access does not fit into bank.");
        return ERROR_FLASH_DST_BREAKS_ALIGNMENT;
    }
 
    if (!c->prot_blocks || c->num_prot_blocks == 0) {
        /* flash driver does not define protect blocks, use sectors instead */
        iterate_protect_blocks = false;
    }
 
    if (iterate_protect_blocks) {
        block_array = c->prot_blocks;
        num_blocks = c->num_prot_blocks;
    } else {
        block_array = c->sectors;
        num_blocks = c->num_sectors;
    }
 
    for (i = 0; i < num_blocks; i++) {
        struct flash_sector *f = &block_array[i];
        target_addr_t sector_addr = c->base + f->offset;
        target_addr_t sector_last_addr = sector_addr + f->size - 1;
 
        /* start only on a sector boundary */
        if (first < 0) {
            /* scanned past the first sector? */
            if (addr < sector_addr)
                break;
 
            /* is this the first sector? */
            if (addr == sector_addr)
                first = i;
 
            /* Does this need head-padding?  If so, pad and warn;
             * or else force an error.
             *
             * Such padding can make trouble, since *WE* can't
             * ever know if that data was in use.  The warning
             * should help users sort out messes later.
             */
            else if (addr <= sector_last_addr && pad_reason) {
                /* FIXME say how many bytes (e.g. 80 KB) */
                LOG_WARNING("Adding extra %s range, "
                    TARGET_ADDR_FMT " .. " TARGET_ADDR_FMT,
                    pad_reason,
                    sector_addr,
                    addr - 1);
                first = i;
            } else
                continue;
        }
 
        /* is this (also?) the last sector? */
        if (last_addr == sector_last_addr) {
            last = i;
            break;
        }
 
        /* Does this need tail-padding?  If so, pad and warn;
         * or else force an error.
         */
        if (last_addr < sector_last_addr && pad_reason) {
            /* FIXME say how many bytes (e.g. 80 KB) */
            LOG_WARNING("Adding extra %s range, "
                TARGET_ADDR_FMT " .. " TARGET_ADDR_FMT,
                pad_reason,
                last_addr + 1,
                sector_last_addr);
            last = i;
            break;
        }
 
        /* MUST finish on a sector boundary */
        if (last_addr < sector_addr)
            break;
    }
 
    /* invalid start or end address? */
    if (first == -1 || last == -1) {
        LOG_ERROR("address range " TARGET_ADDR_FMT " .. " TARGET_ADDR_FMT
            " is not sector-aligned",
            addr,
            last_addr);
        return ERROR_FLASH_DST_BREAKS_ALIGNMENT;
    }
 
    /* The NOR driver may trim this range down, based on what
     * sectors are already erased/unprotected.  GDB currently
     * blocks such optimizations.
     */
    return callback(c, first, last);
}
 
/* The inner fn only handles a single bank, we could be spanning
 * multiple chips.
 */
static int flash_iterate_address_range(struct target *target,
    char *pad_reason, target_addr_t addr, uint32_t length,
    bool iterate_protect_blocks,
    int (*callback)(struct flash_bank *bank, unsigned int first,
        unsigned int last))
{
    struct flash_bank *c;
    int retval = ERROR_OK;
 
    /* Danger! zero-length iterations means entire bank! */
    do {
        retval = get_flash_bank_by_addr(target, addr, true, &c);
        if (retval != ERROR_OK)
            return retval;
 
        uint32_t cur_length = length;
        /* check whether it all fits in this bank */
        if (addr + length - 1 > c->base + c->size - 1) {
            LOG_DEBUG("iterating over more than one flash bank.");
            cur_length = c->base + c->size - addr;
        }
        retval = flash_iterate_address_range_inner(target,
                pad_reason, addr, cur_length,
                iterate_protect_blocks,
                callback);
        if (retval != ERROR_OK)
            break;
 
        length -= cur_length;
        addr += cur_length;
    } while (length > 0);
 
    return retval;
}
 
int flash_erase_address_range(struct target *target,
    bool pad, target_addr_t addr, uint32_t length)
{
    return flash_iterate_address_range(target, pad ? "erase" : NULL,
        addr, length, false, &flash_driver_erase);
}
 
static int flash_driver_unprotect(struct flash_bank *bank, unsigned int first,
        unsigned int last)
{
    return flash_driver_protect(bank, 0, first, last);
}
 
int flash_unlock_address_range(struct target *target, target_addr_t addr,
        uint32_t length)
{
    /* By default, pad to sector boundaries ... the real issue here
     * is that our (only) caller *permanently* removes protection,
     * and doesn't restore it.
     */
    return flash_iterate_address_range(target, "unprotect",
        addr, length, true, &flash_driver_unprotect);
}
 
static int compare_section(const void *a, const void *b)
{
    struct imagesection *b1, *b2;
    b1 = *((struct imagesection **)a);
    b2 = *((struct imagesection **)b);
 
    if (b1->base_address == b2->base_address)
        return 0;
    else if (b1->base_address > b2->base_address)
        return 1;
    else
        return -1;
}
 
target_addr_t flash_write_align_start(struct flash_bank *bank, target_addr_t addr)
{
    if (addr < bank->base || addr >= bank->base + bank->size
            || bank->write_start_alignment <= 1)
        return addr;
 
    if (bank->write_start_alignment == FLASH_WRITE_ALIGN_SECTOR) {
        uint32_t offset = addr - bank->base;
        uint32_t aligned = 0;
        for (unsigned int sect = 0; sect < bank->num_sectors; sect++) {
            if (bank->sectors[sect].offset > offset)
                break;
 
            aligned = bank->sectors[sect].offset;
        }
        return bank->base + aligned;
    }
 
    return addr & ~(bank->write_start_alignment - 1);
}
 
target_addr_t flash_write_align_end(struct flash_bank *bank, target_addr_t addr)
{
    if (addr < bank->base || addr >= bank->base + bank->size
            || bank->write_end_alignment <= 1)
        return addr;
 
    if (bank->write_end_alignment == FLASH_WRITE_ALIGN_SECTOR) {
        uint32_t offset = addr - bank->base;
        uint32_t aligned = 0;
        for (unsigned int sect = 0; sect < bank->num_sectors; sect++) {
            aligned = bank->sectors[sect].offset + bank->sectors[sect].size - 1;
            if (aligned >= offset)
                break;
        }
        return bank->base + aligned;
    }
 
    return addr | (bank->write_end_alignment - 1);
}
 
static bool flash_write_check_gap(struct flash_bank *bank,
                target_addr_t addr1, target_addr_t addr2)
{
    if (bank->minimal_write_gap == FLASH_WRITE_CONTINUOUS
            || addr1 < bank->base || addr1 >= bank->base + bank->size
            || addr2 < bank->base || addr2 >= bank->base + bank->size)
        return false;
 
    if (bank->minimal_write_gap == FLASH_WRITE_GAP_SECTOR) {
        unsigned int sect;
        uint32_t offset1 = addr1 - bank->base;
        /* find the sector following the one containing addr1 */
        for (sect = 0; sect < bank->num_sectors; sect++) {
            if (bank->sectors[sect].offset > offset1)
                break;
        }
        if (sect >= bank->num_sectors)
            return false;
 
        uint32_t offset2 = addr2 - bank->base;
        return bank->sectors[sect].offset + bank->sectors[sect].size <= offset2;
    }
 
    target_addr_t aligned1 = flash_write_align_end(bank, addr1);
    target_addr_t aligned2 = flash_write_align_start(bank, addr2);
    return aligned1 + bank->minimal_write_gap < aligned2;
}
 
 
int flash_write_unlock_verify(struct target *target, struct image *image,
    uint32_t *written, bool erase, bool unlock, bool write, bool verify)
{
    int retval = ERROR_OK;
 
    unsigned int section;
    uint32_t section_offset;
    struct flash_bank *c;
    int *padding;
 
    section = 0;
    section_offset = 0;
 
    if (written)
        *written = 0;
 
    if (erase) {
        /* assume all sectors need erasing - stops any problems
         * when flash_write is called multiple times */
 
        flash_set_dirty();
    }
 
    /* allocate padding array */
    padding = calloc(image->num_sections, sizeof(*padding));
 
    /* This fn requires all sections to be in ascending order of addresses,
     * whereas an image can have sections out of order. */
    struct imagesection **sections = malloc(sizeof(struct imagesection *) *
            image->num_sections);
 
    for (unsigned int i = 0; i < image->num_sections; i++)
        sections[i] = &image->sections[i];
 
    qsort(sections, image->num_sections, sizeof(struct imagesection *),
        compare_section);
 
    /* loop until we reach end of the image */
    while (section < image->num_sections) {
        uint32_t buffer_idx;
        uint8_t *buffer;
        unsigned int section_last;
        target_addr_t run_address = sections[section]->base_address + section_offset;
        uint32_t run_size = sections[section]->size - section_offset;
        int pad_bytes = 0;
 
        if (sections[section]->size ==  0) {
            LOG_WARNING("empty section %d", section);
            section++;
            section_offset = 0;
            continue;
        }
 
        /* find the corresponding flash bank */
        retval = get_flash_bank_by_addr(target, run_address, false, &c);
        if (retval != ERROR_OK)
            goto done;
        if (!c) {
            LOG_WARNING("no flash bank found for address " TARGET_ADDR_FMT, run_address);
            section++;  /* and skip it */
            section_offset = 0;
            continue;
        }
 
        /* collect consecutive sections which fall into the same bank */
        section_last = section;
        padding[section] = 0;
        while ((run_address + run_size - 1 < c->base + c->size - 1) &&
                (section_last + 1 < image->num_sections)) {
            /* sections are sorted */
            assert(sections[section_last + 1]->base_address >= c->base);
            if (sections[section_last + 1]->base_address >= (c->base + c->size)) {
                /* Done with this bank */
                break;
            }
 
            /* if we have multiple sections within our image,
             * flash programming could fail due to alignment issues
             * attempt to rebuild a consecutive buffer for the flash loader */
            target_addr_t run_next_addr = run_address + run_size;
            target_addr_t next_section_base = sections[section_last + 1]->base_address;
            if (next_section_base < run_next_addr) {
                LOG_ERROR("Section at " TARGET_ADDR_FMT
                    " overlaps section ending at " TARGET_ADDR_FMT,
                    next_section_base, run_next_addr);
                LOG_ERROR("Flash write aborted.");
                retval = ERROR_FAIL;
                goto done;
            }
 
            pad_bytes = next_section_base - run_next_addr;
            if (pad_bytes) {
                if (flash_write_check_gap(c, run_next_addr - 1, next_section_base)) {
                    LOG_INFO("Flash write discontinued at " TARGET_ADDR_FMT
                        ", next section at " TARGET_ADDR_FMT,
                        run_next_addr, next_section_base);
                    break;
                }
            }
            if (pad_bytes > 0)
                LOG_INFO("Padding image section %d at " TARGET_ADDR_FMT
                    " with %d bytes",
                    section_last, run_next_addr, pad_bytes);
 
            padding[section_last] = pad_bytes;
            run_size += pad_bytes;
            run_size += sections[++section_last]->size;
        }
 
        if (run_address + run_size - 1 > c->base + c->size - 1) {
            /* If we have more than one flash chip back to back, then we limit
             * the current write operation to the current chip.
             */
            LOG_DEBUG("Truncate flash run size to the current flash chip.");
 
            run_size = c->base + c->size - run_address;
            assert(run_size > 0);
        }
 
        uint32_t padding_at_start = 0;
        if (c->write_start_alignment || c->write_end_alignment) {
            /* align write region according to bank requirements */
            target_addr_t aligned_start = flash_write_align_start(c, run_address);
            padding_at_start = run_address - aligned_start;
            if (padding_at_start > 0) {
                LOG_WARNING("Section start address " TARGET_ADDR_FMT
                    " breaks the required alignment of flash bank %s",
                    run_address, c->name);
                LOG_WARNING("Padding %" PRIu32 " bytes from " TARGET_ADDR_FMT,
                    padding_at_start, aligned_start);
 
                run_address -= padding_at_start;
                run_size += padding_at_start;
            }
 
            target_addr_t run_end = run_address + run_size - 1;
            target_addr_t aligned_end = flash_write_align_end(c, run_end);
            pad_bytes = aligned_end - run_end;
            if (pad_bytes > 0) {
                LOG_INFO("Padding image section %d at " TARGET_ADDR_FMT
                    " with %d bytes (bank write end alignment)",
                    section_last, run_end + 1, pad_bytes);
 
                padding[section_last] += pad_bytes;
                run_size += pad_bytes;
            }
 
        } else if (unlock || erase) {
            /* If we're applying any sector automagic, then pad this
             * (maybe-combined) segment to the end of its last sector.
             */
            uint32_t offset_start = run_address - c->base;
            uint32_t offset_end = offset_start + run_size;
            uint32_t end = offset_end, delta;
 
            for (unsigned int sector = 0; sector < c->num_sectors; sector++) {
                end = c->sectors[sector].offset
                    + c->sectors[sector].size;
                if (offset_end <= end)
                    break;
            }
 
            delta = end - offset_end;
            padding[section_last] += delta;
            run_size += delta;
        }
 
        /* allocate buffer */
        buffer = malloc(run_size);
        if (!buffer) {
            LOG_ERROR("Out of memory for flash bank buffer");
            retval = ERROR_FAIL;
            goto done;
        }
 
        if (padding_at_start)
            memset(buffer, c->default_padded_value, padding_at_start);
 
        buffer_idx = padding_at_start;
 
        /* read sections to the buffer */
        while (buffer_idx < run_size) {
            size_t size_read;
 
            size_read = run_size - buffer_idx;
            if (size_read > sections[section]->size - section_offset)
                size_read = sections[section]->size - section_offset;
 
            /* KLUDGE!
             *
             * #¤%#"%¤% we have to figure out the section # from the sorted
             * list of pointers to sections to invoke image_read_section()...
             */
            intptr_t diff = (intptr_t)sections[section] - (intptr_t)image->sections;
            int t_section_num = diff / sizeof(struct imagesection);
 
            LOG_DEBUG("image_read_section: section = %d, t_section_num = %d, "
                    "section_offset = %"PRIu32", buffer_idx = %"PRIu32", size_read = %zu",
                section, t_section_num, section_offset,
                buffer_idx, size_read);
            retval = image_read_section(image, t_section_num, section_offset,
                    size_read, buffer + buffer_idx, &size_read);
            if (retval != ERROR_OK || size_read == 0) {
                free(buffer);
                goto done;
            }
 
            buffer_idx += size_read;
            section_offset += size_read;
 
            /* see if we need to pad the section */
            if (padding[section]) {
                memset(buffer + buffer_idx, c->default_padded_value, padding[section]);
                buffer_idx += padding[section];
            }
 
            if (section_offset >= sections[section]->size) {
                section++;
                section_offset = 0;
            }
        }
 
        retval = ERROR_OK;
 
        if (unlock)
            retval = flash_unlock_address_range(target, run_address, run_size);
        if (retval == ERROR_OK) {
            if (erase) {
                /* calculate and erase sectors */
                retval = flash_erase_address_range(target,
                        true, run_address, run_size);
            }
        }
 
        if (retval == ERROR_OK) {
            if (write) {
                /* write flash sectors */
                retval = flash_driver_write(c, buffer, run_address - c->base, run_size);
            }
        }
 
        if (retval == ERROR_OK) {
            if (verify) {
                /* verify flash sectors */
                retval = flash_driver_verify(c, buffer, run_address - c->base, run_size);
            }
        }
 
        free(buffer);
 
        if (retval != ERROR_OK) {
            /* abort operation */
            goto done;
        }
 
        if (written)
            *written += run_size;   /* add run size to total written counter */
    }
 
done:
    free(sections);
    free(padding);
 
    return retval;
}
 
int flash_write(struct target *target, struct image *image,
    uint32_t *written, bool erase)
{
    return flash_write_unlock_verify(target, image, written, erase, false, true, false);
}
 
struct flash_sector *alloc_block_array(uint32_t offset, uint32_t size,
        unsigned int num_blocks)
{
    struct flash_sector *array = calloc(num_blocks, sizeof(struct flash_sector));
    if (!array)
        return NULL;
 
    for (unsigned int i = 0; i < num_blocks; i++) {
        array[i].offset = offset;
        array[i].size = size;
        array[i].is_erased = -1;
        array[i].is_protected = -1;
        offset += size;
    }
 
    return array;
}