flash/nor: handle flash write alignment/padding in the infrastructure

[openocd.git] / src / flash / nor / core.c

/***************************************************************************
 *   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>                   *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>. *
 ***************************************************************************/

#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>

/**
 * @file
 * Upper level of NOR flash framework.
 * The lower level interfaces are to drivers.  These upper level ones
 * primarily support access from Tcl scripts or from GDB.
 */

static struct flash_bank *flash_banks;

int flash_driver_erase(struct flash_bank *bank, int first, int last)
{
        int retval;

        retval = bank->driver->erase(bank, first, last);
        if (retval != ERROR_OK)
                LOG_ERROR("failed erasing sectors %d to %d", first, last);

        return retval;
}

int flash_driver_protect(struct flash_bank *bank, int set, int first, int last)
{
        int retval;
        int num_blocks;

        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 < 0 || 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 %d to %d", first, last);

        return retval;
}

int flash_driver_write(struct flash_bank *bank,
        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 0x%08" PRIx32 " 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 0x%08" PRIx32 " 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);
}

void flash_bank_add(struct flash_bank *bank)
{
        /* put flash bank in linked list */
        unsigned bank_num = 0;
        if (flash_banks) {
                /* find last flash bank */
                struct flash_bank *p = flash_banks;
                while (NULL != 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(int num)
{
        struct flash_bank *p;
        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;
}

int flash_get_bank_count(void)
{
        struct flash_bank *p;
        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->name);
                free(bank->sectors);
                free(bank->prot_blocks);
                free(bank);
                bank = next;
        }
        flash_banks = NULL;
}

struct flash_bank *get_flash_bank_by_name_noprobe(const char *name)
{
        unsigned requested = get_flash_name_index(name);
        unsigned found = 0;

        struct flash_bank *bank;
        for (bank = flash_banks; NULL != 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 != NULL) {
                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(int num, struct flash_bank **bank)
{
        struct flash_bank *p = get_flash_bank_by_num_noprobe(num);
        int retval;

        if (p == NULL)
                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,
        uint32_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 0x%08" PRIx32, 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;
        int i;
        uint32_t nBytes;
        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 (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 > (j - bank->sectors[i].size))
                                chunk = (j - bank->sectors[i].size);

                        retval = target_read_memory(target,
                                        bank->base + bank->sectors[i].offset + j,
                                        4,
                                        chunk/4,
                                        buffer);
                        if (retval != ERROR_OK)
                                goto done;

                        for (nBytes = 0; nBytes < chunk; nBytes++) {
                                if (buffer[nBytes] != 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 i;
        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 == NULL)
                return default_flash_mem_blank_check(bank);

        for (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 (i = 0; i < bank->num_sectors; ) {
                retval = target_blank_check_memory(target,
                                block_array + i, bank->num_sectors - i,
                                bank->erased_value);
                if (retval < 1) {
                        /* Run slow fallback if the first run gives no result
                         * otherwise use possibly incomplete results */
                        if (i == 0)
                                fast_check = false;
                        break;
                }
                i += retval; /* add number of blocks done this round */
        }

        if (fast_check) {
                for (i = 0; i < bank->num_sectors; i++)
                        bank->sectors[i].is_erased = block_array[i].result;
                retval = ERROR_OK;
        } 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, uint32_t addr, uint32_t length,
        bool iterate_protect_blocks,
        int (*callback)(struct flash_bank *bank, int first, int last))
{
        struct flash_bank *c;
        struct flash_sector *block_array;
        uint32_t last_addr = addr + length;     /* first address AFTER end */
        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 (addr + length - 1 > c->base + c->size - 1) {
                LOG_ERROR("Flash access does not fit into bank.");
                return ERROR_FLASH_DST_BREAKS_ALIGNMENT;
        }

        if (c->prot_blocks == NULL || 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;
        }

        addr -= c->base;
        last_addr -= c->base;

        for (i = 0; i < num_blocks; i++) {
                struct flash_sector *f = &block_array[i];
                uint32_t end = f->offset + f->size;

                /* start only on a sector boundary */
                if (first < 0) {
                        /* scanned past the first sector? */
                        if (addr < f->offset)
                                break;

                        /* is this the first sector? */
                        if (addr == f->offset)
                                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 < end && pad_reason) {
                                /* FIXME say how many bytes (e.g. 80 KB) */
                                LOG_WARNING("Adding extra %s range, "
                                        "%#8.8x to %#8.8x",
                                        pad_reason,
                                        (unsigned) f->offset,
                                        (unsigned) addr - 1);
                                first = i;
                        } else
                                continue;
                }

                /* is this (also?) the last sector? */
                if (last_addr == end) {
                        last = i;
                        break;
                }

                /* Does this need tail-padding?  If so, pad and warn;
                 * or else force an error.
                 */
                if (last_addr < end && pad_reason) {
                        /* FIXME say how many bytes (e.g. 80 KB) */
                        LOG_WARNING("Adding extra %s range, "
                                "%#8.8x to %#8.8x",
                                pad_reason,
                                (unsigned) last_addr,
                                (unsigned) end - 1);
                        last = i;
                        break;
                }

                /* MUST finish on a sector boundary */
                if (last_addr <= f->offset)
                        break;
        }

        /* invalid start or end address? */
        if (first == -1 || last == -1) {
                LOG_ERROR("address range 0x%8.8x .. 0x%8.8x "
                        "is not sector-aligned",
                        (unsigned) (c->base + addr),
                        (unsigned) (c->base + last_addr - 1));
                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, uint32_t addr, uint32_t length,
        bool iterate_protect_blocks,
        int (*callback)(struct flash_bank *bank, int first, 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, uint32_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, int first, int last)
{
        return flash_driver_protect(bank, 0, first, last);
}

int flash_unlock_address_range(struct target *target, uint32_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;
}

/**
 * Get aligned start address of a flash write region
 */
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;
                int sect;
                for (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);
}

/**
 * Get aligned end address of a flash write region
 */
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;
                int sect;
                for (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);
}

/**
 * Check if gap between sections is bigger than minimum required to discontinue flash write
 */
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) {
                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(struct target *target, struct image *image,
        uint32_t *written, int erase, bool unlock)
{
        int retval = ERROR_OK;

        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);
        int i;
        for (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;
                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 == NULL) {
                        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 %d 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.
                         */
                        int sector;
                        uint32_t offset_start = run_address - c->base;
                        uint32_t offset_end = offset_start + run_size;
                        uint32_t end = offset_end, delta;

                        for (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 == NULL) {
                        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) {
                        /* write flash sectors */
                        retval = flash_driver_write(c, buffer, run_address - c->base, run_size);
                }

                free(buffer);

                if (retval != ERROR_OK) {
                        /* abort operation */
                        goto done;
                }

                if (written != NULL)
                        *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, int erase)
{
        return flash_write_unlock(target, image, written, erase, false);
}

struct flash_sector *alloc_block_array(uint32_t offset, uint32_t size, int num_blocks)
{
        int i;

        struct flash_sector *array = calloc(num_blocks, sizeof(struct flash_sector));
        if (array == NULL)
                return NULL;

        for (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;
}