stm32lx: refactor and add support for STM32L0xx

[openocd.git] / src / flash / nor / stm32lx.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 by Clement Burin des Roziers                       *
 *   clement.burin-des-roziers@hikob.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.,                                       *
 *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.           *
 ***************************************************************************/

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

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

/* stm32lx flash register locations */

#define FLASH_ACR               0x00
#define FLASH_PECR              0x04
#define FLASH_PDKEYR    0x08
#define FLASH_PEKEYR    0x0C
#define FLASH_PRGKEYR   0x10
#define FLASH_OPTKEYR   0x14
#define FLASH_SR                0x18
#define FLASH_OBR               0x1C
#define FLASH_WRPR              0x20

/* FLASH_ACR bites */
#define FLASH_ACR__LATENCY              (1<<0)
#define FLASH_ACR__PRFTEN               (1<<1)
#define FLASH_ACR__ACC64                (1<<2)
#define FLASH_ACR__SLEEP_PD             (1<<3)
#define FLASH_ACR__RUN_PD               (1<<4)

/* FLASH_PECR bits */
#define FLASH_PECR__PELOCK              (1<<0)
#define FLASH_PECR__PRGLOCK             (1<<1)
#define FLASH_PECR__OPTLOCK             (1<<2)
#define FLASH_PECR__PROG                (1<<3)
#define FLASH_PECR__DATA                (1<<4)
#define FLASH_PECR__FTDW                (1<<8)
#define FLASH_PECR__ERASE               (1<<9)
#define FLASH_PECR__FPRG                (1<<10)
#define FLASH_PECR__EOPIE               (1<<16)
#define FLASH_PECR__ERRIE               (1<<17)
#define FLASH_PECR__OBL_LAUNCH  (1<<18)

/* FLASH_SR bits */
#define FLASH_SR__BSY           (1<<0)
#define FLASH_SR__EOP           (1<<1)
#define FLASH_SR__ENDHV         (1<<2)
#define FLASH_SR__READY         (1<<3)
#define FLASH_SR__WRPERR        (1<<8)
#define FLASH_SR__PGAERR        (1<<9)
#define FLASH_SR__SIZERR        (1<<10)
#define FLASH_SR__OPTVERR       (1<<11)

/* Unlock keys */
#define PEKEY1                  0x89ABCDEF
#define PEKEY2                  0x02030405
#define PRGKEY1                 0x8C9DAEBF
#define PRGKEY2                 0x13141516
#define OPTKEY1                 0xFBEAD9C8
#define OPTKEY2                 0x24252627

/* other registers */
#define DBGMCU_IDCODE           0xE0042000
#define DBGMCU_IDCODE_L0        0x40015800

/* Constants */
#define FLASH_SECTOR_SIZE 4096
#define FLASH_BANK0_ADDRESS 0x08000000

static int stm32lx_unlock_program_memory(struct flash_bank *bank);
static int stm32lx_lock_program_memory(struct flash_bank *bank);
static int stm32lx_enable_write_half_page(struct flash_bank *bank);
static int stm32lx_erase_sector(struct flash_bank *bank, int sector);
static int stm32lx_wait_until_bsy_clear(struct flash_bank *bank);

struct stm32lx_rev {
        uint16_t rev;
        const char *str;
};

struct stm32lx_part_info {
        uint16_t id;
        const char *device_str;
        const struct stm32lx_rev *revs;
        size_t num_revs;
        unsigned int page_size;
        unsigned int pages_per_sector;
        uint16_t max_flash_size_kb;
        uint16_t first_bank_size_kb; /* used when has_dual_banks is true */
        bool has_dual_banks;

        uint32_t flash_base;    /* Flash controller registers location */
        uint32_t fsize_base;    /* Location of FSIZE register */
};

struct stm32lx_flash_bank {
        int probed;
        uint32_t idcode;
        uint32_t user_bank_size;
        uint32_t flash_base;

        const struct stm32lx_part_info *part_info;
};

static const struct stm32lx_rev stm32_416_revs[] = {
        { 0x1000, "A" }, { 0x1008, "Y" }, { 0x1018, "X" }, { 0x1038, "W" },
        { 0x1078, "V" },
};
static const struct stm32lx_rev stm32_417_revs[] = {
        { 0x1000, "A" }, { 0x1008, "Z" },
};
static const struct stm32lx_rev stm32_427_revs[] = {
        { 0x1018, "A" },
};
static const struct stm32lx_rev stm32_436_revs[] = {
        { 0x1000, "A" }, { 0x1008, "Z" }, { 0x1018, "Y" },
};

static const struct stm32lx_part_info stm32lx_parts[] = {
        {
                .id                                     = 0x416,
                .revs                           = stm32_416_revs,
                .num_revs                       = ARRAY_SIZE(stm32_416_revs),
                .device_str                     = "STM32L1xx (Low/Medium Density)",
                .page_size                      = 256,
                .pages_per_sector       = 16,
                .max_flash_size_kb      = 128,
                .has_dual_banks         = false,
                .flash_base                     = 0x40023C00,
                .fsize_base                     = 0x1FF8004C,
        },
        {
                .id                                     = 0x417,
                .revs                           = stm32_417_revs,
                .num_revs                       = ARRAY_SIZE(stm32_417_revs),
                .device_str                     = "STM32L0xx",
                .page_size                      = 128,
                .pages_per_sector       = 32,
                .max_flash_size_kb      = 64,
                .has_dual_banks         = false,
                .flash_base                     = 0x40022000,
                .fsize_base                     = 0x1FF8007C,
        },
        {
                .id                                     = 0x427,
                .revs                           = stm32_427_revs,
                .num_revs                       = ARRAY_SIZE(stm32_427_revs),
                .device_str                     = "STM32L1xx (Medium+ Density)",
                .page_size                      = 256,
                .pages_per_sector       = 16,
                .max_flash_size_kb      = 256,
                .first_bank_size_kb     = 192,
                .has_dual_banks         = true,
                .flash_base                     = 0x40023C00,
                .fsize_base                     = 0x1FF800CC,
        },
        {
                .id                                     = 0x436,
                .revs                           = stm32_436_revs,
                .num_revs                       = ARRAY_SIZE(stm32_436_revs),
                .device_str                     = "STM32L1xx (Medium+/High Density)",
                .page_size                      = 256,
                .pages_per_sector       = 16,
                .max_flash_size_kb      = 384,
                .first_bank_size_kb     = 192,
                .has_dual_banks         = true,
                .flash_base                     = 0x40023C00,
                .fsize_base                     = 0x1FF800CC,
        },
        {
                .id                                     = 0x437,
                .device_str                     = "STM32L1xx (Medium+/High Density)",
                .page_size                      = 256,
                .pages_per_sector       = 16,
                .max_flash_size_kb      = 512,
                .first_bank_size_kb     = 256,
                .has_dual_banks         = true,
                .flash_base                     = 0x40023C00,
                .fsize_base                     = 0x1FF800CC,
        },
};

/* flash bank stm32lx <base> <size> 0 0 <target#>
 */
FLASH_BANK_COMMAND_HANDLER(stm32lx_flash_bank_command)
{
        struct stm32lx_flash_bank *stm32lx_info;
        if (CMD_ARGC < 6)
                return ERROR_COMMAND_SYNTAX_ERROR;

        /* Create the bank structure */
        stm32lx_info = malloc(sizeof(struct stm32lx_flash_bank));

        /* Check allocation */
        if (stm32lx_info == NULL) {
                LOG_ERROR("failed to allocate bank structure");
                return ERROR_FAIL;
        }

        bank->driver_priv = stm32lx_info;

        stm32lx_info->probed = 0;
        stm32lx_info->user_bank_size = bank->size;

        /* the stm32l erased value is 0x00 */
        bank->default_padded_value = 0x00;

        return ERROR_OK;
}

static int stm32lx_protect_check(struct flash_bank *bank)
{
        int retval;
        struct target *target = bank->target;
        struct stm32lx_flash_bank *stm32lx_info = bank->driver_priv;

        uint32_t wrpr;

        /*
         * Read the WRPR word, and check each bit (corresponding to each
         * flash sector
         */
        retval = target_read_u32(target, stm32lx_info->flash_base + FLASH_WRPR,
                        &wrpr);
        if (retval != ERROR_OK)
                return retval;

        for (int i = 0; i < bank->num_sectors; i++) {
                if (wrpr & (1 << i))
                        bank->sectors[i].is_protected = 1;
                else
                        bank->sectors[i].is_protected = 0;
        }
        return ERROR_OK;
}

static int stm32lx_erase(struct flash_bank *bank, int first, int last)
{
        int retval;

        /*
         * It could be possible to do a mass erase if all sectors must be
         * erased, but it is not implemented yet.
         */

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

        /*
         * Loop over the selected sectors and erase them
         */
        for (int i = first; i <= last; i++) {
                retval = stm32lx_erase_sector(bank, i);
                if (retval != ERROR_OK)
                        return retval;
                bank->sectors[i].is_erased = 1;
        }
        return ERROR_OK;
}

static int stm32lx_protect(struct flash_bank *bank, int set, int first,
                int last)
{
        LOG_WARNING("protection of the STM32L flash is not implemented");
        return ERROR_OK;
}

static int stm32lx_write_half_pages(struct flash_bank *bank, const uint8_t *buffer,
                uint32_t offset, uint32_t count)
{
        struct target *target = bank->target;
        struct stm32lx_flash_bank *stm32lx_info = bank->driver_priv;

        uint32_t hp_nb = stm32lx_info->part_info->page_size / 2;
        uint32_t buffer_size = 16384;
        struct working_area *write_algorithm;
        struct working_area *source;
        uint32_t address = bank->base + offset;

        struct reg_param reg_params[3];
        struct armv7m_algorithm armv7m_info;

        int retval = ERROR_OK;

        /* see contib/loaders/flash/stm32lx.S for src */

        static const uint8_t stm32lx_flash_write_code[] = {
                /* write_word: */
                0x00, 0x23,             /* movs r3, #0 */
                0x04, 0xe0,             /* b test_done */

                /* write_word: */
                0x51, 0xf8, 0x04, 0xcb, /* ldr ip, [r1], #4 */
                0x40, 0xf8, 0x04, 0xcb, /* str ip, [r0], #4 */
                0x01, 0x33,             /* adds r3, #1 */

                /* test_done: */
                0x93, 0x42,             /* cmp r3, r2 */
                0xf8, 0xd3,             /* bcc write_word */
                0x00, 0xbe,             /* bkpt 0 */

        };

        /* Make sure we're performing a half-page aligned write. */
        if (count % hp_nb) {
                LOG_ERROR("The byte count must be %" PRIu32 "B-aligned but count is %" PRIi32 "B)", hp_nb, count);
                return ERROR_FAIL;
        }

        /* flash write code */
        if (target_alloc_working_area(target, sizeof(stm32lx_flash_write_code),
                        &write_algorithm) != ERROR_OK) {
                LOG_DEBUG("no working area for block memory writes");
                return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
        };

        /* Write the flashing code */
        retval = target_write_buffer(target,
                        write_algorithm->address,
                        sizeof(stm32lx_flash_write_code),
                        stm32lx_flash_write_code);
        if (retval != ERROR_OK) {
                target_free_working_area(target, write_algorithm);
                return retval;
        }

        /* Allocate half pages memory */
        while (target_alloc_working_area_try(target, buffer_size, &source) != ERROR_OK) {
                if (buffer_size > 1024)
                        buffer_size -= 1024;
                else
                        buffer_size /= 2;

                if (buffer_size <= stm32lx_info->part_info->page_size) {
                        /* we already allocated the writing code, but failed to get a
                         * buffer, free the algorithm */
                        target_free_working_area(target, 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 = ARM_MODE_THREAD;
        init_reg_param(&reg_params[0], "r0", 32, PARAM_OUT);
        init_reg_param(&reg_params[1], "r1", 32, PARAM_OUT);
        init_reg_param(&reg_params[2], "r2", 32, PARAM_OUT);

        /* Enable half-page write */
        retval = stm32lx_enable_write_half_page(bank);
        if (retval != ERROR_OK) {
                target_free_working_area(target, source);
                target_free_working_area(target, write_algorithm);

                destroy_reg_param(&reg_params[0]);
                destroy_reg_param(&reg_params[1]);
                destroy_reg_param(&reg_params[2]);
                return retval;
        }

        struct armv7m_common *armv7m = target_to_armv7m(target);
        if (armv7m == NULL) {

                /* something is very wrong if armv7m is NULL */
                LOG_ERROR("unable to get armv7m target");
                return retval;
        }

        /* save any DEMCR flags and configure target to catch any Hard Faults */
        uint32_t demcr_save = armv7m->demcr;
        armv7m->demcr = VC_HARDERR;

        /* Loop while there are bytes to write */
        while (count > 0) {
                uint32_t this_count;
                this_count = (count > buffer_size) ? buffer_size : count;

                /* Write the next half pages */
                retval = target_write_buffer(target, source->address, this_count, buffer);
                if (retval != ERROR_OK)
                        break;

                /* 4: Store useful information in the registers */
                /* the destination address of the copy (R0) */
                buf_set_u32(reg_params[0].value, 0, 32, address);
                /* The source address of the copy (R1) */
                buf_set_u32(reg_params[1].value, 0, 32, source->address);
                /* The length of the copy (R2) */
                buf_set_u32(reg_params[2].value, 0, 32, this_count / 4);

                /* 5: Execute the bunch of code */
                retval = target_run_algorithm(target, 0, NULL, sizeof(reg_params)
                                / sizeof(*reg_params), reg_params,
                                write_algorithm->address, 0, 10000, &armv7m_info);
                if (retval != ERROR_OK)
                        break;

                /* check for Hard Fault */
                if (armv7m->exception_number == 3)
                        break;

                /* 6: Wait while busy */
                retval = stm32lx_wait_until_bsy_clear(bank);
                if (retval != ERROR_OK)
                        break;

                buffer += this_count;
                address += this_count;
                count -= this_count;
        }

        /* restore previous flags */
        armv7m->demcr = demcr_save;

        if (armv7m->exception_number == 3) {

                /* the stm32l15x devices seem to have an issue when blank.
                 * if a ram loader is executed on a blank device it will
                 * Hard Fault, this issue does not happen for a already programmed device.
                 * A related issue is described in the stm32l151xx errata (Doc ID 17721 Rev 6 - 2.1.3).
                 * The workaround of handling the Hard Fault exception does work, but makes the
                 * loader more complicated, as a compromise we manually write the pages, programming time
                 * is reduced by 50% using this slower method.
                 */

                LOG_WARNING("couldn't use loader, falling back to page memory writes");

                while (count > 0) {
                        uint32_t this_count;
                        this_count = (count > hp_nb) ? hp_nb : count;

                        /* Write the next half pages */
                        retval = target_write_buffer(target, address, this_count, buffer);
                        if (retval != ERROR_OK)
                                break;

                        /* Wait while busy */
                        retval = stm32lx_wait_until_bsy_clear(bank);
                        if (retval != ERROR_OK)
                                break;

                        buffer += this_count;
                        address += this_count;
                        count -= this_count;
                }
        }

        if (retval == ERROR_OK)
                retval = stm32lx_lock_program_memory(bank);

        target_free_working_area(target, source);
        target_free_working_area(target, write_algorithm);

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

        return retval;
}

static int stm32lx_write(struct flash_bank *bank, const uint8_t *buffer,
                uint32_t offset, uint32_t count)
{
        struct target *target = bank->target;
        struct stm32lx_flash_bank *stm32lx_info = bank->driver_priv;

        uint32_t hp_nb = stm32lx_info->part_info->page_size / 2;
        uint32_t halfpages_number;
        uint32_t bytes_remaining = 0;
        uint32_t address = bank->base + offset;
        uint32_t bytes_written = 0;
        int retval, retval2;

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

        if (offset & 0x3) {
                LOG_ERROR("offset 0x%" PRIx32 " breaks required 4-byte alignment", offset);
                return ERROR_FLASH_DST_BREAKS_ALIGNMENT;
        }

        retval = stm32lx_unlock_program_memory(bank);
        if (retval != ERROR_OK)
                return retval;

        /* first we need to write any unaligned head bytes upto
         * the next 128 byte page */

        if (offset % hp_nb)
                bytes_remaining = MIN(count, hp_nb - (offset % hp_nb));

        while (bytes_remaining > 0) {
                uint8_t value[4] = {0xff, 0xff, 0xff, 0xff};

                /* copy remaining bytes into the write buffer */
                uint32_t bytes_to_write = MIN(4, bytes_remaining);
                memcpy(value, buffer + bytes_written, bytes_to_write);

                retval = target_write_buffer(target, address, 4, value);
                if (retval != ERROR_OK)
                        goto reset_pg_and_lock;

                bytes_written += bytes_to_write;
                bytes_remaining -= bytes_to_write;
                address += 4;

                retval = stm32lx_wait_until_bsy_clear(bank);
                if (retval != ERROR_OK)
                        goto reset_pg_and_lock;
        }

        offset += bytes_written;
        count -= bytes_written;

        /* this should always pass this check here */
        assert((offset % hp_nb) == 0);

        /* calculate half pages */
        halfpages_number = count / hp_nb;

        if (halfpages_number) {
                retval = stm32lx_write_half_pages(bank, buffer + bytes_written, offset, hp_nb * halfpages_number);
                if (retval == ERROR_TARGET_RESOURCE_NOT_AVAILABLE) {
                        /* attempt slow memory writes */
                        LOG_WARNING("couldn't use block writes, falling back to single memory accesses");
                        halfpages_number = 0;
                } else {
                        if (retval != ERROR_OK)
                                return ERROR_FAIL;
                }
        }

        /* write any remaining bytes */
        uint32_t page_bytes_written = hp_nb * halfpages_number;
        bytes_written += page_bytes_written;
        address += page_bytes_written;
        bytes_remaining = count - page_bytes_written;

        retval = stm32lx_unlock_program_memory(bank);
        if (retval != ERROR_OK)
                return retval;

        while (bytes_remaining > 0) {
                uint8_t value[4] = {0xff, 0xff, 0xff, 0xff};

                /* copy remaining bytes into the write buffer */
                uint32_t bytes_to_write = MIN(4, bytes_remaining);
                memcpy(value, buffer + bytes_written, bytes_to_write);

                retval = target_write_buffer(target, address, 4, value);
                if (retval != ERROR_OK)
                        goto reset_pg_and_lock;

                bytes_written += bytes_to_write;
                bytes_remaining -= bytes_to_write;
                address += 4;

                retval = stm32lx_wait_until_bsy_clear(bank);
                if (retval != ERROR_OK)
                        goto reset_pg_and_lock;
        }

reset_pg_and_lock:
        retval2 = stm32lx_lock_program_memory(bank);
        if (retval == ERROR_OK)
                retval = retval2;

        return retval;
}

static int stm32lx_read_id_code(struct target *target, uint32_t *id)
{
        /* read stm32 device id register */
        int retval = target_read_u32(target, DBGMCU_IDCODE, id);
        if (retval != ERROR_OK)
                return retval;

        /* STM32L0 parts will have 0 there, try reading the L0's location for
         * DBG_IDCODE in case this is an L0 part. */
        if (*id == 0)
                retval = target_read_u32(target, DBGMCU_IDCODE_L0, id);

        return retval;
}

static int stm32lx_probe(struct flash_bank *bank)
{
        struct target *target = bank->target;
        struct stm32lx_flash_bank *stm32lx_info = bank->driver_priv;
        int i;
        uint16_t flash_size_in_kb;
        uint32_t device_id;
        uint32_t base_address = FLASH_BANK0_ADDRESS;
        uint32_t second_bank_base;

        stm32lx_info->probed = 0;

        int retval = stm32lx_read_id_code(bank->target, &device_id);
        if (retval != ERROR_OK)
                return retval;

        stm32lx_info->idcode = device_id;

        LOG_DEBUG("device id = 0x%08" PRIx32 "", device_id);

        for (unsigned int n = 0; n < ARRAY_SIZE(stm32lx_parts); n++) {
                if ((device_id & 0xfff) == stm32lx_parts[n].id)
                        stm32lx_info->part_info = &stm32lx_parts[n];
        }

        if (!stm32lx_info->part_info) {
                LOG_WARNING("Cannot identify target as a STM32L family.");
                return ERROR_FAIL;
        }

        stm32lx_info->flash_base = stm32lx_info->part_info->flash_base;

        /* Get the flash size from target. */
        retval = target_read_u16(target, stm32lx_info->part_info->fsize_base,
                        &flash_size_in_kb);

        /* 0x436 devices report their flash size as a 0 or 1 code indicating 384K
         * or 256K, respectively.  Please see RM0038 r8 or newer and refer to
         * section 30.1.1. */
        if (retval == ERROR_OK && (device_id & 0xfff) == 0x436) {
                if (flash_size_in_kb == 0)
                        flash_size_in_kb = 384;
                else if (flash_size_in_kb == 1)
                        flash_size_in_kb = 256;
        }

        /* Failed reading flash size or flash size invalid (early silicon),
         * default to max target family */
        if (retval != ERROR_OK || flash_size_in_kb == 0xffff || flash_size_in_kb == 0) {
                LOG_WARNING("STM32L flash size failed, probe inaccurate - assuming %dk flash",
                        stm32lx_info->part_info->max_flash_size_kb);
                flash_size_in_kb = stm32lx_info->part_info->max_flash_size_kb;
        } else if (flash_size_in_kb > stm32lx_info->part_info->max_flash_size_kb) {
                LOG_WARNING("STM32L probed flash size assumed incorrect since FLASH_SIZE=%dk > %dk, - assuming %dk flash",
                        flash_size_in_kb, stm32lx_info->part_info->max_flash_size_kb,
                        stm32lx_info->part_info->max_flash_size_kb);
                flash_size_in_kb = stm32lx_info->part_info->max_flash_size_kb;
        }

        if (stm32lx_info->part_info->has_dual_banks) {
                /* Use the configured base address to determine if this is the first or second flash bank.
                 * Verify that the base address is reasonably correct and determine the flash bank size
                 */
                second_bank_base = base_address +
                        stm32lx_info->part_info->first_bank_size_kb * 1024;
                if (bank->base == second_bank_base) {
                        /* This is the second bank  */
                        base_address = second_bank_base;
                        flash_size_in_kb = flash_size_in_kb -
                                stm32lx_info->part_info->first_bank_size_kb;
                } else if (bank->base == 0 || bank->base == base_address) {
                        /* This is the first bank */
                        flash_size_in_kb = stm32lx_info->part_info->first_bank_size_kb;
                } else {
                        LOG_WARNING("STM32L flash bank base address config is incorrect."
                                    " 0x%" PRIx32 " but should rather be 0x%" PRIx32 " or 0x%" PRIx32,
                                                bank->base, base_address, second_bank_base);
                        return ERROR_FAIL;
                }
                LOG_INFO("STM32L flash has dual banks. Bank (%d) size is %dkb, base address is 0x%" PRIx32,
                                bank->bank_number, flash_size_in_kb, base_address);
        } else {
                LOG_INFO("STM32L flash size is %dkb, base address is 0x%" PRIx32, flash_size_in_kb, base_address);
        }

        /* if the user sets the size manually then ignore the probed value
         * this allows us to work around devices that have a invalid flash size register value */
        if (stm32lx_info->user_bank_size) {
                flash_size_in_kb = stm32lx_info->user_bank_size / 1024;
                LOG_INFO("ignoring flash probed value, using configured bank size: %dkbytes", flash_size_in_kb);
        }

        /* calculate numbers of sectors (4kB per sector) */
        int num_sectors = (flash_size_in_kb * 1024) / FLASH_SECTOR_SIZE;

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

        bank->size = flash_size_in_kb * 1024;
        bank->base = base_address;
        bank->num_sectors = num_sectors;
        bank->sectors = malloc(sizeof(struct flash_sector) * num_sectors);
        if (bank->sectors == NULL) {
                LOG_ERROR("failed to allocate bank sectors");
                return ERROR_FAIL;
        }

        for (i = 0; i < num_sectors; i++) {
                bank->sectors[i].offset = i * FLASH_SECTOR_SIZE;
                bank->sectors[i].size = FLASH_SECTOR_SIZE;
                bank->sectors[i].is_erased = -1;
                bank->sectors[i].is_protected = 1;
        }

        stm32lx_info->probed = 1;

        return ERROR_OK;
}

static int stm32lx_auto_probe(struct flash_bank *bank)
{
        struct stm32lx_flash_bank *stm32lx_info = bank->driver_priv;

        if (stm32lx_info->probed)
                return ERROR_OK;

        return stm32lx_probe(bank);
}

static int stm32lx_erase_check(struct flash_bank *bank)
{
        struct target *target = bank->target;
        const int buffer_size = 4096;
        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);
        if (buffer == NULL) {
                LOG_ERROR("failed to allocate read buffer");
                return ERROR_FAIL;
        }

        for (i = 0; i < bank->num_sectors; i++) {
                uint32_t j;
                bank->sectors[i].is_erased = 1;

                /* Loop chunk by chunk over the sector */
                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)
                                break;

                        for (nBytes = 0; nBytes < chunk; nBytes++) {
                                if (buffer[nBytes] != 0x00) {
                                        bank->sectors[i].is_erased = 0;
                                        break;
                                }
                        }
                }
                if (retval != ERROR_OK)
                        break;
        }
        free(buffer);

        return retval;
}

/* This method must return a string displaying information about the bank */
static int stm32lx_get_info(struct flash_bank *bank, char *buf, int buf_size)
{
        struct stm32lx_flash_bank *stm32lx_info = bank->driver_priv;

        if (!stm32lx_info->probed) {
                int retval = stm32lx_probe(bank);
                if (retval != ERROR_OK) {
                        snprintf(buf, buf_size,
                                "Unable to find bank information.");
                        return retval;
                }
        }


        const struct stm32lx_part_info *info = stm32lx_info->part_info;

        if (info) {
                const char *rev_str = NULL;
                uint16_t rev_id = stm32lx_info->idcode >> 16;

                for (unsigned int i = 0; i < info->num_revs; i++)
                        if (rev_id == info->revs[i].rev)
                                rev_str = info->revs[i].str;

                if (rev_str != NULL) {
                        snprintf(buf, buf_size,
                                "%s - Rev: %s",
                                stm32lx_info->part_info->device_str, rev_str);
                } else {
                        snprintf(buf, buf_size,
                                "%s - Rev: unknown (0x%04x)",
                                stm32lx_info->part_info->device_str, rev_id);
                }

                return ERROR_OK;
        } else {
                snprintf(buf, buf_size, "Cannot identify target as a STM32Lx");

                return ERROR_FAIL;
        }
}

static const struct command_registration stm32lx_exec_command_handlers[] = {
        COMMAND_REGISTRATION_DONE
};

static const struct command_registration stm32lx_command_handlers[] = {
        {
                .name = "stm32lx",
                .mode = COMMAND_ANY,
                .help = "stm32lx flash command group",
                .usage = "",
                .chain = stm32lx_exec_command_handlers,
        },
        COMMAND_REGISTRATION_DONE
};

struct flash_driver stm32lx_flash = {
                .name = "stm32lx",
                .commands = stm32lx_command_handlers,
                .flash_bank_command = stm32lx_flash_bank_command,
                .erase = stm32lx_erase,
                .protect = stm32lx_protect,
                .write = stm32lx_write,
                .read = default_flash_read,
                .probe = stm32lx_probe,
                .auto_probe = stm32lx_auto_probe,
                .erase_check = stm32lx_erase_check,
                .protect_check = stm32lx_protect_check,
                .info = stm32lx_get_info,
};

/* Static methods implementation */
static int stm32lx_unlock_program_memory(struct flash_bank *bank)
{
        struct target *target = bank->target;
        struct stm32lx_flash_bank *stm32lx_info = bank->driver_priv;
        int retval;
        uint32_t reg32;

        /*
         * Unlocking the program memory is done by unlocking the PECR,
         * then by writing the 2 PRGKEY to the PRGKEYR register
         */

        /* check flash is not already unlocked */
        retval = target_read_u32(target, stm32lx_info->flash_base + FLASH_PECR,
                        &reg32);
        if (retval != ERROR_OK)
                return retval;

        if ((reg32 & FLASH_PECR__PRGLOCK) == 0)
                return ERROR_OK;

        /* To unlock the PECR write the 2 PEKEY to the PEKEYR register */
        retval = target_write_u32(target, stm32lx_info->flash_base + FLASH_PEKEYR,
                        PEKEY1);
        if (retval != ERROR_OK)
                return retval;

        retval = target_write_u32(target, stm32lx_info->flash_base + FLASH_PEKEYR,
                        PEKEY2);
        if (retval != ERROR_OK)
                return retval;

        /* Make sure it worked */
        retval = target_read_u32(target, stm32lx_info->flash_base + FLASH_PECR,
                        &reg32);
        if (retval != ERROR_OK)
                return retval;

        if (reg32 & FLASH_PECR__PELOCK) {
                LOG_ERROR("PELOCK is not cleared :(");
                return ERROR_FLASH_OPERATION_FAILED;
        }

        retval = target_write_u32(target, stm32lx_info->flash_base + FLASH_PRGKEYR,
                        PRGKEY1);
        if (retval != ERROR_OK)
                return retval;
        retval = target_write_u32(target, stm32lx_info->flash_base + FLASH_PRGKEYR,
                        PRGKEY2);
        if (retval != ERROR_OK)
                return retval;

        /* Make sure it worked */
        retval = target_read_u32(target, stm32lx_info->flash_base + FLASH_PECR,
                        &reg32);
        if (retval != ERROR_OK)
                return retval;

        if (reg32 & FLASH_PECR__PRGLOCK) {
                LOG_ERROR("PRGLOCK is not cleared :(");
                return ERROR_FLASH_OPERATION_FAILED;
        }

        return ERROR_OK;
}

static int stm32lx_enable_write_half_page(struct flash_bank *bank)
{
        struct target *target = bank->target;
        struct stm32lx_flash_bank *stm32lx_info = bank->driver_priv;
        int retval;
        uint32_t reg32;

        /**
         * Unlock the program memory, then set the FPRG bit in the PECR register.
         */
        retval = stm32lx_unlock_program_memory(bank);
        if (retval != ERROR_OK)
                return retval;

        retval = target_read_u32(target, stm32lx_info->flash_base + FLASH_PECR,
                        &reg32);
        if (retval != ERROR_OK)
                return retval;

        reg32 |= FLASH_PECR__FPRG;
        retval = target_write_u32(target, stm32lx_info->flash_base + FLASH_PECR,
                        reg32);
        if (retval != ERROR_OK)
                return retval;

        retval = target_read_u32(target, stm32lx_info->flash_base + FLASH_PECR,
                        &reg32);
        if (retval != ERROR_OK)
                return retval;

        reg32 |= FLASH_PECR__PROG;
        retval = target_write_u32(target, stm32lx_info->flash_base + FLASH_PECR,
                        reg32);

        return retval;
}

static int stm32lx_lock_program_memory(struct flash_bank *bank)
{
        struct target *target = bank->target;
        struct stm32lx_flash_bank *stm32lx_info = bank->driver_priv;
        int retval;
        uint32_t reg32;

        /* To lock the program memory, simply set the lock bit and lock PECR */

        retval = target_read_u32(target, stm32lx_info->flash_base + FLASH_PECR,
                        &reg32);
        if (retval != ERROR_OK)
                return retval;

        reg32 |= FLASH_PECR__PRGLOCK;
        retval = target_write_u32(target, stm32lx_info->flash_base + FLASH_PECR,
                        reg32);
        if (retval != ERROR_OK)
                return retval;

        retval = target_read_u32(target, stm32lx_info->flash_base + FLASH_PECR,
                        &reg32);
        if (retval != ERROR_OK)
                return retval;

        reg32 |= FLASH_PECR__PELOCK;
        retval = target_write_u32(target, stm32lx_info->flash_base + FLASH_PECR,
                        reg32);
        if (retval != ERROR_OK)
                return retval;

        return ERROR_OK;
}

static int stm32lx_erase_sector(struct flash_bank *bank, int sector)
{
        struct target *target = bank->target;
        struct stm32lx_flash_bank *stm32lx_info = bank->driver_priv;
        int retval;
        uint32_t reg32;

        /*
         * To erase a sector (i.e. stm32lx_info->part_info.pages_per_sector pages),
         * first unlock the memory, loop over the pages of this sector
         * and write 0x0 to its first word.
         */

        retval = stm32lx_unlock_program_memory(bank);
        if (retval != ERROR_OK)
                return retval;

        for (int page = 0; page < (int)stm32lx_info->part_info->pages_per_sector;
                        page++) {
                reg32 = FLASH_PECR__PROG | FLASH_PECR__ERASE;
                retval = target_write_u32(target,
                                stm32lx_info->flash_base + FLASH_PECR, reg32);
                if (retval != ERROR_OK)
                        return retval;

                retval = stm32lx_wait_until_bsy_clear(bank);
                if (retval != ERROR_OK)
                        return retval;

                uint32_t addr = bank->base + bank->sectors[sector].offset + (page
                                * stm32lx_info->part_info->page_size);
                retval = target_write_u32(target, addr, 0x0);
                if (retval != ERROR_OK)
                        return retval;

                retval = stm32lx_wait_until_bsy_clear(bank);
                if (retval != ERROR_OK)
                        return retval;
        }

        retval = stm32lx_lock_program_memory(bank);
        if (retval != ERROR_OK)
                return retval;

        return ERROR_OK;
}

static int stm32lx_wait_until_bsy_clear(struct flash_bank *bank)
{
        struct target *target = bank->target;
        struct stm32lx_flash_bank *stm32lx_info = bank->driver_priv;
        uint32_t status;
        int retval = ERROR_OK;
        int timeout = 100;

        /* wait for busy to clear */
        for (;;) {
                retval = target_read_u32(target, stm32lx_info->flash_base + FLASH_SR,
                                &status);
                if (retval != ERROR_OK)
                        return retval;

                if ((status & FLASH_SR__BSY) == 0)
                        break;
                if (timeout-- <= 0) {
                        LOG_ERROR("timed out waiting for flash");
                        return ERROR_FAIL;
                }
                alive_sleep(1);
        }

        if (status & FLASH_SR__WRPERR) {
                LOG_ERROR("access denied / write protected");
                retval = ERROR_FAIL;
        }

        if (status & FLASH_SR__PGAERR) {
                LOG_ERROR("invalid program address");
                retval = ERROR_FAIL;
        }

        return retval;
}