flash: add stm32f2x async flash loader

[openocd.git] / src / flash / nor / stm32f2x.c

/***************************************************************************
 *   Copyright (C) 2005 by Dominic Rath                                    *
 *   Dominic.Rath@gmx.de                                                   *
 *                                                                         *
 *   Copyright (C) 2008 by Spencer Oliver                                  *
 *   spen@spen-soft.co.uk                                                  *
 *                                                                         *
 *   Copyright (C) 2011 Øyvind Harboe                                      *
 *   oyvind.harboe@zylin.com                                               *
 *                                                                         *
 *   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, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "imp.h"
#include <helper/binarybuffer.h>
#include <target/algorithm.h>
#include <target/armv7m.h>

/* Regarding performance:
 *
 * Short story - it might be best to leave the performance at
 * current levels.
 *
 * You may see a jump in speed if you change to using
 * 32bit words for the block programming.
 *
 * Its a shame you cannot use the double word as its
 * even faster - but you require external VPP for that mode.
 *
 * Having said all that 16bit writes give us the widest vdd
 * operating range, so may be worth adding a note to that effect.
 *
 */

/* Danger!!!! The STM32F1x and STM32F2x series actually have
 * quite different flash controllers.
 *
 * What's more scary is that the names of the registers and their
 * addresses are the same, but the actual bits and what they do are
 * can be very different.
 *
 * To reduce testing complexity and dangers of regressions,
 * a seperate file is used for stm32fx2x.
 *
 * 1mByte part with 4 x 16, 1 x 64, 7 x 128kBytes sectors
 *
 * What's the protection page size???
 *
 * Tested with STM3220F-EVAL board.
 *
 * STM32F21xx series for reference.
 *
 * RM0033
 * http://www.st.com/internet/mcu/product/250192.jsp
 *
 * PM0059
 * www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/
 * PROGRAMMING_MANUAL/CD00233952.pdf
 *
 * STM32F1x series - notice that this code was copy, pasted and knocked
 * into a stm32f2x driver, so in case something has been converted or
 * bugs haven't been fixed, here are the original manuals:
 *
 * RM0008 - Reference manual
 *
 * RM0042, the Flash programming manual for low-, medium- high-density and
 * connectivity line STM32F10x devices
 *
 * PM0068, the Flash programming manual for XL-density STM32F10x devices.
 *
 */

/* Erase time can be as high as 1000ms, 10x this and it's toast... */
#define FLASH_ERASE_TIMEOUT 10000
#define FLASH_WRITE_TIMEOUT 5

#define STM32_FLASH_BASE        0x40023c00
#define STM32_FLASH_ACR         0x40023c00
#define STM32_FLASH_KEYR        0x40023c04
#define STM32_FLASH_OPTKEYR     0x40023c08
#define STM32_FLASH_SR          0x40023c0C
#define STM32_FLASH_CR          0x40023c10
#define STM32_FLASH_OPTCR       0x40023c14
#define STM32_FLASH_OBR         0x40023c1C

/* option byte location */

#define STM32_OB_RDP            0x1FFFF800
#define STM32_OB_USER           0x1FFFF802
#define STM32_OB_DATA0          0x1FFFF804
#define STM32_OB_DATA1          0x1FFFF806
#define STM32_OB_WRP0           0x1FFFF808
#define STM32_OB_WRP1           0x1FFFF80A
#define STM32_OB_WRP2           0x1FFFF80C
#define STM32_OB_WRP3           0x1FFFF80E

/* FLASH_CR register bits */

#define FLASH_PG                (1 << 0)
#define FLASH_SER               (1 << 1)
#define FLASH_MER               (1 << 2)
#define FLASH_STRT              (1 << 16)
#define FLASH_PSIZE_8   (0 << 8)
#define FLASH_PSIZE_16  (1 << 8)
#define FLASH_PSIZE_32  (2 << 8)
#define FLASH_PSIZE_64  (3 << 8)
#define FLASH_SNB(a)    ((a) << 3)
#define FLASH_LOCK              (1 << 31)

/* FLASH_SR register bits */

#define FLASH_BSY               (1 << 16)
#define FLASH_PGSERR    (1 << 7) /* Programming sequence error */
#define FLASH_PGPERR    (1 << 6) /* Programming parallelism error */
#define FLASH_PGAERR    (1 << 5) /* Programming alignment error */
#define FLASH_WRPERR    (1 << 4) /* Write protection error */
#define FLASH_OPERR             (1 << 1) /* Operation error */

#define FLASH_ERROR (FLASH_PGSERR | FLASH_PGPERR | FLASH_PGAERR | FLASH_WRPERR | FLASH_OPERR)

/* STM32_FLASH_OBR bit definitions (reading) */

#define OPT_ERROR               0
#define OPT_READOUT             1
#define OPT_RDWDGSW             2
#define OPT_RDRSTSTOP   3
#define OPT_RDRSTSTDBY  4
#define OPT_BFB2                5       /* dual flash bank only */

/* register unlock keys */

#define KEY1                    0x45670123
#define KEY2                    0xCDEF89AB

struct stm32x_flash_bank {
        struct working_area *write_algorithm;
        int probed;
};


/* flash bank stm32x <base> <size> 0 0 <target#>
 */
FLASH_BANK_COMMAND_HANDLER(stm32x_flash_bank_command)
{
        struct stm32x_flash_bank *stm32x_info;

        if (CMD_ARGC < 6)
                return ERROR_COMMAND_SYNTAX_ERROR;

        stm32x_info = malloc(sizeof(struct stm32x_flash_bank));
        bank->driver_priv = stm32x_info;

        stm32x_info->write_algorithm = NULL;
        stm32x_info->probed = 0;

        return ERROR_OK;
}

static inline int stm32x_get_flash_reg(struct flash_bank *bank, uint32_t reg)
{
        return reg;
}

static inline int stm32x_get_flash_status(struct flash_bank *bank, uint32_t *status)
{
        struct target *target = bank->target;
        return target_read_u32(target, stm32x_get_flash_reg(bank, STM32_FLASH_SR), status);
}

static int stm32x_wait_status_busy(struct flash_bank *bank, int timeout)
{
        struct target *target = bank->target;
        uint32_t status;
        int retval = ERROR_OK;

        /* wait for busy to clear */
        for (;;) {
                retval = stm32x_get_flash_status(bank, &status);
                if (retval != ERROR_OK)
                        return retval;
                LOG_DEBUG("status: 0x%" PRIx32 "", status);
                if ((status & FLASH_BSY) == 0)
                        break;
                if (timeout-- <= 0) {
                        LOG_ERROR("timed out waiting for flash");
                        return ERROR_FAIL;
                }
                alive_sleep(1);
        }


        if (status & FLASH_WRPERR) {
                LOG_ERROR("stm32x device protected");
                retval = ERROR_FAIL;
        }

        /* Clear but report errors */
        if (status & FLASH_ERROR) {
                /* If this operation fails, we ignore it and report the original
                 * retval
                 */
                target_write_u32(target, stm32x_get_flash_reg(bank, STM32_FLASH_SR),
                                status & FLASH_ERROR);
        }
        return retval;
}

static int stm32x_unlock_reg(struct target *target)
{
        uint32_t ctrl;

        /* first check if not already unlocked
         * otherwise writing on STM32_FLASH_KEYR will fail
         */
        int retval = target_read_u32(target, STM32_FLASH_CR, &ctrl);
        if (retval != ERROR_OK)
                return retval;

        if ((ctrl & FLASH_LOCK) == 0)
                return ERROR_OK;

        /* unlock flash registers */
        retval = target_write_u32(target, STM32_FLASH_KEYR, KEY1);
        if (retval != ERROR_OK)
                return retval;

        retval = target_write_u32(target, STM32_FLASH_KEYR, KEY2);
        if (retval != ERROR_OK)
                return retval;

        retval = target_read_u32(target, STM32_FLASH_CR, &ctrl);
        if (retval != ERROR_OK)
                return retval;

        if (ctrl & FLASH_LOCK) {
                LOG_ERROR("flash not unlocked STM32_FLASH_CR: %x", ctrl);
                return ERROR_TARGET_FAILURE;
        }

        return ERROR_OK;
}

static int stm32x_protect_check(struct flash_bank *bank)
{
        return ERROR_OK;
}

static int stm32x_erase(struct flash_bank *bank, int first, int last)
{
        struct target *target = bank->target;
        int i;

        if (bank->target->state != TARGET_HALTED) {
                LOG_ERROR("Target not halted");
                return ERROR_TARGET_NOT_HALTED;
        }

        int retval;
        retval = stm32x_unlock_reg(target);
        if (retval != ERROR_OK)
                return retval;

        /*
        Sector Erase
        To erase a sector, follow the procedure below:
        1. Check that no Flash memory operation is ongoing by checking the BSY bit in the
          FLASH_SR register
        2. Set the SER bit and select the sector (out of the 12 sectors in the main memory block)
          you wish to erase (SNB) in the FLASH_CR register
        3. Set the STRT bit in the FLASH_CR register
        4. Wait for the BSY bit to be cleared
         */

        for (i = first; i <= last; i++) {
                retval = target_write_u32(target,
                                stm32x_get_flash_reg(bank, STM32_FLASH_CR), FLASH_SER | FLASH_SNB(i) | FLASH_STRT);
                if (retval != ERROR_OK)
                        return retval;

                retval = stm32x_wait_status_busy(bank, FLASH_ERASE_TIMEOUT);
                if (retval != ERROR_OK)
                        return retval;

                bank->sectors[i].is_erased = 1;
        }

        retval = target_write_u32(target, stm32x_get_flash_reg(bank, STM32_FLASH_CR), FLASH_LOCK);
        if (retval != ERROR_OK)
                return retval;

        return ERROR_OK;
}

static int stm32x_protect(struct flash_bank *bank, int set, int first, int last)
{
        return ERROR_OK;
}

static int stm32x_write_block(struct flash_bank *bank, uint8_t *buffer,
                uint32_t offset, uint32_t count)
{
        struct stm32x_flash_bank *stm32x_info = bank->driver_priv;
        struct target *target = bank->target;
        uint32_t buffer_size = 16384;
        struct working_area *source;
        uint32_t address = bank->base + offset;
        struct reg_param reg_params[5];
        struct armv7m_algorithm armv7m_info;
        int retval = ERROR_OK;

        /* see contrib/loaders/flash/stm32f2x.S for src */

        static const uint8_t stm32x_flash_write_code[] = {
                                                                        /* wait_fifo: */
                0xD0, 0xF8, 0x00, 0x80,         /* ldr          r8, [r0, #0] */
                0xB8, 0xF1, 0x00, 0x0F,         /* cmp          r8, #0 */
                0x1A, 0xD0,                                     /* beq          exit */
                0x47, 0x68,                                     /* ldr          r7, [r0, #4] */
                0x47, 0x45,                                     /* cmp          r7, r8 */
                0xF7, 0xD0,                                     /* beq          wait_fifo */

                0xDF, 0xF8, 0x30, 0x60,         /* ldr          r6, STM32_PROG16 */
                0x26, 0x61,                                     /* str          r6, [r4, #STM32_FLASH_CR_OFFSET] */
                0x37, 0xF8, 0x02, 0x6B,         /* ldrh         r6, [r7], #0x02 */
                0x22, 0xF8, 0x02, 0x6B,         /* strh         r6, [r2], #0x02 */
                                                                        /* busy: */
                0xE6, 0x68,                                     /* ldr          r6, [r4, #STM32_FLASH_SR_OFFSET] */
                0x16, 0xF4, 0x80, 0x3F,         /* tst          r6, #0x10000 */
                0xFB, 0xD1,                                     /* bne          busy */
                0x16, 0xF0, 0xF0, 0x0F,         /* tst          r6, #0xf0 */
                0x07, 0xD1,                                     /* bne          error */

                0x8F, 0x42,                                     /* cmp          r7, r1 */
                0x28, 0xBF,                                     /* it           cs */
                0x00, 0xF1, 0x08, 0x07,         /* addcs        r7, r0, #8 */
                0x47, 0x60,                                     /* str          r7, [r0, #4] */
                0x01, 0x3B,                                     /* subs         r3, r3, #1 */
                0x13, 0xB1,                                     /* cbz          r3, exit */
                0xE1, 0xE7,                                     /* b            wait_fifo */
                                                                        /* error: */
                0x00, 0x21,                                     /* movs         r1, #0 */
                0x41, 0x60,                                     /* str          r1, [r0, #4] */
                                                                        /* exit: */
                0x30, 0x46,                                     /* mov          r0, r6 */
                0x00, 0xBE,                                     /* bkpt         #0x00 */

                /* <STM32_PROG16>: */
                0x01, 0x01, 0x00, 0x00,         /* .word        0x00000101 */
        };

        if (target_alloc_working_area(target, sizeof(stm32x_flash_write_code),
                        &stm32x_info->write_algorithm) != ERROR_OK) {
                LOG_WARNING("no working area available, can't do block memory writes");
                return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
        };

        retval = target_write_buffer(target, stm32x_info->write_algorithm->address,
                        sizeof(stm32x_flash_write_code),
                        (uint8_t *)stm32x_flash_write_code);
        if (retval != ERROR_OK)
                return retval;

        /* memory buffer */
        while (target_alloc_working_area_try(target, buffer_size, &source) != ERROR_OK) {
                buffer_size /= 2;
                if (buffer_size <= 256) {
                        /* if we already allocated the writing code, but failed to get a
                         * buffer, free the algorithm */
                        if (stm32x_info->write_algorithm)
                                target_free_working_area(target, stm32x_info->write_algorithm);

                        LOG_WARNING("no large enough working area available, can't do block memory writes");
                        return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
                }
        };

        armv7m_info.common_magic = ARMV7M_COMMON_MAGIC;
        armv7m_info.core_mode = ARMV7M_MODE_ANY;

        init_reg_param(&reg_params[0], "r0", 32, PARAM_IN_OUT);         /* buffer start, status (out) */
        init_reg_param(&reg_params[1], "r1", 32, PARAM_OUT);            /* buffer end */
        init_reg_param(&reg_params[2], "r2", 32, PARAM_OUT);            /* target address */
        init_reg_param(&reg_params[3], "r3", 32, PARAM_OUT);            /* count (halfword-16bit) */
        init_reg_param(&reg_params[4], "r4", 32, PARAM_OUT);            /* flash base */

        buf_set_u32(reg_params[0].value, 0, 32, source->address);
        buf_set_u32(reg_params[1].value, 0, 32, source->address + source->size);
        buf_set_u32(reg_params[2].value, 0, 32, address);
        buf_set_u32(reg_params[3].value, 0, 32, count);
        buf_set_u32(reg_params[4].value, 0, 32, STM32_FLASH_BASE);

        retval = target_run_flash_async_algorithm(target, buffer, count, 2,
                        0, NULL,
                        5, reg_params,
                        source->address, source->size,
                        stm32x_info->write_algorithm->address, 0,
                        &armv7m_info);

        if (retval == ERROR_FLASH_OPERATION_FAILED) {
                LOG_ERROR("error executing stm32x flash write algorithm");

                uint32_t error = buf_get_u32(reg_params[0].value, 0, 32) & FLASH_ERROR;

                if (error & FLASH_WRPERR)
                        LOG_ERROR("flash memory write protected");

                if (error != 0) {
                        LOG_ERROR("flash write failed = %08x", error);
                        /* Clear but report errors */
                        target_write_u32(target, STM32_FLASH_SR, error);
                        retval = ERROR_FAIL;
                }
        }

        target_free_working_area(target, source);
        target_free_working_area(target, stm32x_info->write_algorithm);

        destroy_reg_param(&reg_params[0]);
        destroy_reg_param(&reg_params[1]);
        destroy_reg_param(&reg_params[2]);
        destroy_reg_param(&reg_params[3]);
        destroy_reg_param(&reg_params[4]);

        return retval;
}

static int stm32x_write(struct flash_bank *bank, uint8_t *buffer,
                uint32_t offset, uint32_t count)
{
        struct target *target = bank->target;
        uint32_t words_remaining = (count / 2);
        uint32_t bytes_remaining = (count & 0x00000001);
        uint32_t address = bank->base + offset;
        uint32_t bytes_written = 0;
        int retval;

        if (bank->target->state != TARGET_HALTED) {
                LOG_ERROR("Target not halted");
                return ERROR_TARGET_NOT_HALTED;
        }

        if (offset & 0x1) {
                LOG_WARNING("offset 0x%" PRIx32 " breaks required 2-byte alignment", offset);
                return ERROR_FLASH_DST_BREAKS_ALIGNMENT;
        }

        retval = stm32x_unlock_reg(target);
        if (retval != ERROR_OK)
                return retval;

        /* multiple half words (2-byte) to be programmed? */
        if (words_remaining > 0) {
                /* try using a block write */
                retval = stm32x_write_block(bank, buffer, offset, words_remaining);
                if (retval != ERROR_OK) {
                        if (retval == ERROR_TARGET_RESOURCE_NOT_AVAILABLE) {
                                /* if block write failed (no sufficient working area),
                                 * we use normal (slow) single dword accesses */
                                LOG_WARNING("couldn't use block writes, falling back to single memory accesses");
                        }
                } else {
                        buffer += words_remaining * 2;
                        address += words_remaining * 2;
                        words_remaining = 0;
                }
        }

        if ((retval != ERROR_OK) && (retval != ERROR_TARGET_RESOURCE_NOT_AVAILABLE))
                return retval;

        /*
        Standard programming
        The Flash memory programming sequence is as follows:
        1. Check that no main Flash memory operation is ongoing by checking the BSY bit in the
          FLASH_SR register.
        2. Set the PG bit in the FLASH_CR register
        3. Perform the data write operation(s) to the desired memory address (inside main
          memory block or OTP area):
        – – Half-word access in case of x16 parallelism
        – Word access in case of x32 parallelism
        –
        4.
        Byte access in case of x8 parallelism
        Double word access in case of x64 parallelism
        Wait for the BSY bit to be cleared
        */
        while (words_remaining > 0) {
                uint16_t value;
                memcpy(&value, buffer + bytes_written, sizeof(uint16_t));

                retval = target_write_u32(target, stm32x_get_flash_reg(bank, STM32_FLASH_CR),
                                FLASH_PG | FLASH_PSIZE_16);
                if (retval != ERROR_OK)
                        return retval;

                retval = target_write_u16(target, address, value);
                if (retval != ERROR_OK)
                        return retval;

                retval = stm32x_wait_status_busy(bank, FLASH_WRITE_TIMEOUT);
                if (retval != ERROR_OK)
                        return retval;

                bytes_written += 2;
                words_remaining--;
                address += 2;
        }

        if (bytes_remaining) {
                retval = target_write_u32(target, stm32x_get_flash_reg(bank, STM32_FLASH_CR),
                                FLASH_PG | FLASH_PSIZE_8);
                if (retval != ERROR_OK)
                        return retval;
                retval = target_write_u8(target, address, buffer[bytes_written]);
                if (retval != ERROR_OK)
                        return retval;

                retval = stm32x_wait_status_busy(bank, FLASH_WRITE_TIMEOUT);
                if (retval != ERROR_OK)
                        return retval;
        }

        return target_write_u32(target, STM32_FLASH_CR, FLASH_LOCK);
}

static void setup_sector(struct flash_bank *bank, int start, int num, int size)
{
        for (int i = start; i < (start + num) ; i++) {
                bank->sectors[i].offset = bank->size;
                bank->sectors[i].size = size;
                bank->size += bank->sectors[i].size;
        }
}

static int stm32x_get_device_id(struct flash_bank *bank, uint32_t *device_id)
{
        /* this checks for a stm32f4x errata issue where a
         * stm32f2x DBGMCU_IDCODE is incorrectly returned.
         * If the issue is detected target is forced to stm32f4x Rev A.
         * Only effects Rev A silicon */

        struct target *target = bank->target;
        uint32_t cpuid;

        /* read stm32 device id register */
        int retval = target_read_u32(target, 0xE0042000, device_id);
        if (retval != ERROR_OK)
                return retval;

        if ((*device_id & 0xfff) == 0x411) {
                /* read CPUID reg to check core type */
                retval = target_read_u32(target, 0xE000ED00, &cpuid);
                if (retval != ERROR_OK)
                        return retval;

                /* check for cortex_m4 */
                if (((cpuid >> 4) & 0xFFF) == 0xC24) {
                        *device_id &= ~((0xFFFF << 16) | 0xfff);
                        *device_id |= (0x1000 << 16) | 0x413;
                        LOG_INFO("stm32f4x errata detected - fixing incorrect MCU_IDCODE");
                }
        }
        return retval;
}

static int stm32x_probe(struct flash_bank *bank)
{
        struct target *target = bank->target;
        struct stm32x_flash_bank *stm32x_info = bank->driver_priv;
        int i;
        uint16_t flash_size_in_kb;
        uint32_t device_id;
        uint32_t base_address = 0x08000000;

        stm32x_info->probed = 0;

        /* read stm32 device id register */
        int retval = stm32x_get_device_id(bank, &device_id);
        if (retval != ERROR_OK)
                return retval;
        LOG_INFO("device id = 0x%08" PRIx32 "", device_id);

        /* get flash size from target. */
        retval = target_read_u16(target, 0x1FFF7A22, &flash_size_in_kb);
        if (retval != ERROR_OK) {
                LOG_WARNING("failed reading flash size, default to max target family");
                /* failed reading flash size, default to max target family */
                flash_size_in_kb = 0xffff;
        }

        if ((device_id & 0xfff) == 0x411) {
                /* check for early silicon */
                if (flash_size_in_kb == 0xffff) {
                        /* number of sectors may be incorrrect on early silicon */
                        LOG_WARNING("STM32 flash size failed, probe inaccurate - assuming 1024k flash");
                        flash_size_in_kb = 1024;
                }
        } else if ((device_id & 0xfff) == 0x413) {
                /* check for early silicon */
                if (flash_size_in_kb == 0xffff) {
                        /* number of sectors may be incorrrect on early silicon */
                        LOG_WARNING("STM32 flash size failed, probe inaccurate - assuming 1024k flash");
                        flash_size_in_kb = 1024;
                }
        } else {
                LOG_WARNING("Cannot identify target as a STM32 family.");
                return ERROR_FAIL;
        }

        LOG_INFO("flash size = %dkbytes", flash_size_in_kb);

        /* did we assign flash size? */
        assert(flash_size_in_kb != 0xffff);

        /* calculate numbers of pages */
        int num_pages = (flash_size_in_kb / 128) + 4;

        /* check that calculation result makes sense */
        assert(num_pages > 0);

        if (bank->sectors) {
                free(bank->sectors);
                bank->sectors = NULL;
        }

        bank->base = base_address;
        bank->num_sectors = num_pages;
        bank->sectors = malloc(sizeof(struct flash_sector) * num_pages);
        bank->size = 0;

        /* fixed memory */
        setup_sector(bank, 0, 4, 16 * 1024);
        setup_sector(bank, 4, 1, 64 * 1024);

        /* dynamic memory */
        setup_sector(bank, 4 + 1, num_pages - 5, 128 * 1024);

        for (i = 0; i < num_pages; i++) {
                bank->sectors[i].is_erased = -1;
                bank->sectors[i].is_protected = 0;
        }

        stm32x_info->probed = 1;

        return ERROR_OK;
}

static int stm32x_auto_probe(struct flash_bank *bank)
{
        struct stm32x_flash_bank *stm32x_info = bank->driver_priv;
        if (stm32x_info->probed)
                return ERROR_OK;
        return stm32x_probe(bank);
}

static int get_stm32x_info(struct flash_bank *bank, char *buf, int buf_size)
{
        uint32_t device_id;
        int printed;

        /* read stm32 device id register */
        int retval = stm32x_get_device_id(bank, &device_id);
        if (retval != ERROR_OK)
                return retval;

        if ((device_id & 0xfff) == 0x411) {
                printed = snprintf(buf, buf_size, "stm32f2x - Rev: ");
                buf += printed;
                buf_size -= printed;

                switch (device_id >> 16) {
                        case 0x1000:
                                snprintf(buf, buf_size, "A");
                                break;

                        case 0x2000:
                                snprintf(buf, buf_size, "B");
                                break;

                        case 0x1001:
                                snprintf(buf, buf_size, "Z");
                                break;

                        case 0x2001:
                                snprintf(buf, buf_size, "Y");
                                break;

                        default:
                                snprintf(buf, buf_size, "unknown");
                                break;
                }
        } else if ((device_id & 0xfff) == 0x413) {
                printed = snprintf(buf, buf_size, "stm32f4x - Rev: ");
                buf += printed;
                buf_size -= printed;

                switch (device_id >> 16) {
                        case 0x1000:
                                snprintf(buf, buf_size, "A");
                                break;

                        case 0x1001:
                                snprintf(buf, buf_size, "Z");
                                break;

                        default:
                                snprintf(buf, buf_size, "unknown");
                                break;
                }
        } else {
                snprintf(buf, buf_size, "Cannot identify target as a stm32x\n");
                return ERROR_FAIL;
        }

        return ERROR_OK;
}

static int stm32x_mass_erase(struct flash_bank *bank)
{
        int retval;
        struct target *target = bank->target;

        if (target->state != TARGET_HALTED) {
                LOG_ERROR("Target not halted");
                return ERROR_TARGET_NOT_HALTED;
        }

        retval = stm32x_unlock_reg(target);
        if (retval != ERROR_OK)
                return retval;

        /* mass erase flash memory */
        retval = target_write_u32(target, stm32x_get_flash_reg(bank, STM32_FLASH_CR), FLASH_MER);
        if (retval != ERROR_OK)
                return retval;
        retval = target_write_u32(target, stm32x_get_flash_reg(bank, STM32_FLASH_CR),
                FLASH_MER | FLASH_STRT);
        if (retval != ERROR_OK)
                return retval;

        retval = stm32x_wait_status_busy(bank, 30000);
        if (retval != ERROR_OK)
                return retval;

        retval = target_write_u32(target, stm32x_get_flash_reg(bank, STM32_FLASH_CR), FLASH_LOCK);
        if (retval != ERROR_OK)
                return retval;

        return ERROR_OK;
}

COMMAND_HANDLER(stm32x_handle_mass_erase_command)
{
        int i;

        if (CMD_ARGC < 1) {
                command_print(CMD_CTX, "stm32x mass_erase <bank>");
                return ERROR_COMMAND_SYNTAX_ERROR;
        }

        struct flash_bank *bank;
        int retval = CALL_COMMAND_HANDLER(flash_command_get_bank, 0, &bank);
        if (ERROR_OK != retval)
                return retval;

        retval = stm32x_mass_erase(bank);
        if (retval == ERROR_OK) {
                /* set all sectors as erased */
                for (i = 0; i < bank->num_sectors; i++)
                        bank->sectors[i].is_erased = 1;

                command_print(CMD_CTX, "stm32x mass erase complete");
        } else {
                command_print(CMD_CTX, "stm32x mass erase failed");
        }

        return retval;
}

static const struct command_registration stm32x_exec_command_handlers[] = {
        {
                .name = "mass_erase",
                .handler = stm32x_handle_mass_erase_command,
                .mode = COMMAND_EXEC,
                .usage = "bank_id",
                .help = "Erase entire flash device.",
        },
        COMMAND_REGISTRATION_DONE
};

static const struct command_registration stm32x_command_handlers[] = {
        {
                .name = "stm32f2x",
                .mode = COMMAND_ANY,
                .help = "stm32f2x flash command group",
                .usage = "",
                .chain = stm32x_exec_command_handlers,
        },
        COMMAND_REGISTRATION_DONE
};

struct flash_driver stm32f2x_flash = {
        .name = "stm32f2x",
        .commands = stm32x_command_handlers,
        .flash_bank_command = stm32x_flash_bank_command,
        .erase = stm32x_erase,
        .protect = stm32x_protect,
        .write = stm32x_write,
        .read = default_flash_read,
        .probe = stm32x_probe,
        .auto_probe = stm32x_auto_probe,
        .erase_check = default_flash_mem_blank_check,
        .protect_check = stm32x_protect_check,
        .info = get_stm32x_info,
};