em357.c

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// SPDX-License-Identifier: GPL-2.0-or-later
 
/***************************************************************************
 *   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 Erik Botö
 *   erik.boto@pelagicore.com
 ***************************************************************************/
 
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
 
#include "imp.h"
#include <helper/binarybuffer.h>
#include <target/algorithm.h>
#include <target/armv7m.h>
 
/* em357 register locations */
 
#define EM357_FLASH_ACR         0x40008000
#define EM357_FLASH_KEYR        0x40008004
#define EM357_FLASH_OPTKEYR     0x40008008
#define EM357_FLASH_SR          0x4000800C
#define EM357_FLASH_CR          0x40008010
#define EM357_FLASH_AR          0x40008014
#define EM357_FLASH_OBR         0x4000801C
#define EM357_FLASH_WRPR        0x40008020
 
#define EM357_FPEC_CLK          0x4000402c
/* option byte location */
 
#define EM357_OB_RDP            0x08040800
#define EM357_OB_WRP0           0x08040808
#define EM357_OB_WRP1           0x0804080A
#define EM357_OB_WRP2           0x0804080C
 
/* FLASH_CR register bits */
 
#define FLASH_PG                (1 << 0)
#define FLASH_PER               (1 << 1)
#define FLASH_MER               (1 << 2)
#define FLASH_OPTPG             (1 << 4)
#define FLASH_OPTER             (1 << 5)
#define FLASH_STRT              (1 << 6)
#define FLASH_LOCK              (1 << 7)
#define FLASH_OPTWRE    (1 << 9)
 
/* FLASH_SR register bits */
 
#define FLASH_BSY               (1 << 0)
#define FLASH_PGERR             (1 << 2)
#define FLASH_WRPRTERR  (1 << 4)
#define FLASH_EOP               (1 << 5)
 
/* EM357_FLASH_OBR bit definitions (reading) */
 
#define OPT_ERROR               0
#define OPT_READOUT             1
 
/* register unlock keys */
 
#define KEY1                    0x45670123
#define KEY2                    0xCDEF89AB
 
struct em357_options {
    uint16_t RDP;
    uint16_t user_options;
    uint16_t protection[3];
};
 
struct em357_flash_bank {
    struct em357_options option_bytes;
    int ppage_size;
    bool probed;
};
 
static int em357_mass_erase(struct flash_bank *bank);
 
/* flash bank em357 <base> <size> 0 0 <target#>
 */
FLASH_BANK_COMMAND_HANDLER(em357_flash_bank_command)
{
    struct em357_flash_bank *em357_info;
 
    if (CMD_ARGC < 6)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    em357_info = malloc(sizeof(struct em357_flash_bank));
    bank->driver_priv = em357_info;
 
    em357_info->probed = false;
 
    return ERROR_OK;
}
 
static inline int em357_get_flash_status(struct flash_bank *bank, uint32_t *status)
{
    struct target *target = bank->target;
    return target_read_u32(target, EM357_FLASH_SR, status);
}
 
static int em357_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 = em357_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_WRPRTERR) {
        LOG_ERROR("em357 device protected");
        retval = ERROR_FAIL;
    }
 
    if (status & FLASH_PGERR) {
        LOG_ERROR("em357 device programming failed");
        retval = ERROR_FAIL;
    }
 
    /* Clear but report errors */
    if (status & (FLASH_WRPRTERR | FLASH_PGERR)) {
        /* If this operation fails, we ignore it and report the original
         * retval
         */
        target_write_u32(target, EM357_FLASH_SR, FLASH_WRPRTERR | FLASH_PGERR);
    }
    return retval;
}
 
static int em357_read_options(struct flash_bank *bank)
{
    uint32_t optiondata;
    struct em357_flash_bank *em357_info = NULL;
    struct target *target = bank->target;
 
    em357_info = bank->driver_priv;
 
    /* read current option bytes */
    int retval = target_read_u32(target, EM357_FLASH_OBR, &optiondata);
    if (retval != ERROR_OK)
        return retval;
 
    em357_info->option_bytes.user_options = (uint16_t)0xFFFC | ((optiondata >> 2) & 0x03);
    em357_info->option_bytes.RDP = (optiondata & (1 << OPT_READOUT)) ? 0xFFFF : 0x5AA5;
 
    if (optiondata & (1 << OPT_READOUT))
        LOG_INFO("Device Security Bit Set");
 
    /* each bit refers to a 4bank protection */
    retval = target_read_u32(target, EM357_FLASH_WRPR, &optiondata);
    if (retval != ERROR_OK)
        return retval;
 
    em357_info->option_bytes.protection[0] = (uint16_t)optiondata;
    em357_info->option_bytes.protection[1] = (uint16_t)(optiondata >> 8);
    em357_info->option_bytes.protection[2] = (uint16_t)(optiondata >> 16);
 
    return ERROR_OK;
}
 
static int em357_erase_options(struct flash_bank *bank)
{
    struct em357_flash_bank *em357_info = NULL;
    struct target *target = bank->target;
 
    em357_info = bank->driver_priv;
 
    /* read current options */
    em357_read_options(bank);
 
    /* unlock flash registers */
    int retval = target_write_u32(target, EM357_FLASH_KEYR, KEY1);
    if (retval != ERROR_OK)
        return retval;
 
    retval = target_write_u32(target, EM357_FLASH_KEYR, KEY2);
    if (retval != ERROR_OK)
        return retval;
 
    /* unlock option flash registers */
    retval = target_write_u32(target, EM357_FLASH_OPTKEYR, KEY1);
    if (retval != ERROR_OK)
        return retval;
    retval = target_write_u32(target, EM357_FLASH_OPTKEYR, KEY2);
    if (retval != ERROR_OK)
        return retval;
 
    /* erase option bytes */
    retval = target_write_u32(target, EM357_FLASH_CR, FLASH_OPTER | FLASH_OPTWRE);
    if (retval != ERROR_OK)
        return retval;
    retval = target_write_u32(target, EM357_FLASH_CR, FLASH_OPTER | FLASH_STRT | FLASH_OPTWRE);
    if (retval != ERROR_OK)
        return retval;
 
    retval = em357_wait_status_busy(bank, 10);
    if (retval != ERROR_OK)
        return retval;
 
    /* clear readout protection and complementary option bytes
     * this will also force a device unlock if set */
    em357_info->option_bytes.RDP = 0x5AA5;
 
    return ERROR_OK;
}
 
static int em357_write_options(struct flash_bank *bank)
{
    struct em357_flash_bank *em357_info = NULL;
    struct target *target = bank->target;
 
    em357_info = bank->driver_priv;
 
    /* unlock flash registers */
    int retval = target_write_u32(target, EM357_FLASH_KEYR, KEY1);
    if (retval != ERROR_OK)
        return retval;
    retval = target_write_u32(target, EM357_FLASH_KEYR, KEY2);
    if (retval != ERROR_OK)
        return retval;
 
    /* unlock option flash registers */
    retval = target_write_u32(target, EM357_FLASH_OPTKEYR, KEY1);
    if (retval != ERROR_OK)
        return retval;
    retval = target_write_u32(target, EM357_FLASH_OPTKEYR, KEY2);
    if (retval != ERROR_OK)
        return retval;
 
    /* program option bytes */
    retval = target_write_u32(target, EM357_FLASH_CR, FLASH_OPTPG | FLASH_OPTWRE);
    if (retval != ERROR_OK)
        return retval;
 
    retval = em357_wait_status_busy(bank, 10);
    if (retval != ERROR_OK)
        return retval;
 
    /* write protection byte 1 */
    retval = target_write_u16(target, EM357_OB_WRP0, em357_info->option_bytes.protection[0]);
    if (retval != ERROR_OK)
        return retval;
 
    retval = em357_wait_status_busy(bank, 10);
    if (retval != ERROR_OK)
        return retval;
 
    /* write protection byte 2 */
    retval = target_write_u16(target, EM357_OB_WRP1, em357_info->option_bytes.protection[1]);
    if (retval != ERROR_OK)
        return retval;
 
    retval = em357_wait_status_busy(bank, 10);
    if (retval != ERROR_OK)
        return retval;
 
    /* write protection byte 3 */
    retval = target_write_u16(target, EM357_OB_WRP2, em357_info->option_bytes.protection[2]);
    if (retval != ERROR_OK)
        return retval;
 
    retval = em357_wait_status_busy(bank, 10);
    if (retval != ERROR_OK)
        return retval;
 
    /* write readout protection bit */
    retval = target_write_u16(target, EM357_OB_RDP, em357_info->option_bytes.RDP);
    if (retval != ERROR_OK)
        return retval;
 
    retval = em357_wait_status_busy(bank, 10);
    if (retval != ERROR_OK)
        return retval;
 
    retval = target_write_u32(target, EM357_FLASH_CR, FLASH_LOCK);
    if (retval != ERROR_OK)
        return retval;
 
    return ERROR_OK;
}
 
static int em357_protect_check(struct flash_bank *bank)
{
    struct target *target = bank->target;
    struct em357_flash_bank *em357_info = bank->driver_priv;
 
    uint32_t protection;
    int i, s;
    int num_bits;
    int set;
 
    if (target->state != TARGET_HALTED) {
        LOG_ERROR("Target not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    /* each bit refers to a 4bank protection (bit 0-23) */
    int retval = target_read_u32(target, EM357_FLASH_WRPR, &protection);
    if (retval != ERROR_OK)
        return retval;
 
    /* each protection bit is for 4 * 2K pages */
    num_bits = (bank->num_sectors / em357_info->ppage_size);
 
    for (i = 0; i < num_bits; i++) {
        set = 1;
        if (protection & (1 << i))
            set = 0;
 
        for (s = 0; s < em357_info->ppage_size; s++)
            bank->sectors[(i * em357_info->ppage_size) + s].is_protected = set;
    }
 
    return ERROR_OK;
}
 
static int em357_erase(struct flash_bank *bank, unsigned int first,
        unsigned int last)
{
    struct target *target = bank->target;
 
    if (bank->target->state != TARGET_HALTED) {
        LOG_ERROR("Target not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    if ((first == 0) && (last == (bank->num_sectors - 1)))
        return em357_mass_erase(bank);
 
    /* Enable FPEC clock */
    target_write_u32(target, EM357_FPEC_CLK, 0x00000001);
 
    /* unlock flash registers */
    int retval = target_write_u32(target, EM357_FLASH_KEYR, KEY1);
    if (retval != ERROR_OK)
        return retval;
    retval = target_write_u32(target, EM357_FLASH_KEYR, KEY2);
    if (retval != ERROR_OK)
        return retval;
 
    for (unsigned int i = first; i <= last; i++) {
        retval = target_write_u32(target, EM357_FLASH_CR, FLASH_PER);
        if (retval != ERROR_OK)
            return retval;
        retval = target_write_u32(target, EM357_FLASH_AR,
                bank->base + bank->sectors[i].offset);
        if (retval != ERROR_OK)
            return retval;
        retval = target_write_u32(target, EM357_FLASH_CR, FLASH_PER | FLASH_STRT);
        if (retval != ERROR_OK)
            return retval;
 
        retval = em357_wait_status_busy(bank, 100);
        if (retval != ERROR_OK)
            return retval;
    }
 
    retval = target_write_u32(target, EM357_FLASH_CR, FLASH_LOCK);
    if (retval != ERROR_OK)
        return retval;
 
    return ERROR_OK;
}
 
static int em357_protect(struct flash_bank *bank, int set, unsigned int first,
        unsigned int last)
{
    struct em357_flash_bank *em357_info = NULL;
    struct target *target = bank->target;
    uint16_t prot_reg[4] = {0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF};
    int reg, bit;
    int status;
    uint32_t protection;
 
    em357_info = bank->driver_priv;
 
    if (target->state != TARGET_HALTED) {
        LOG_ERROR("Target not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    if ((first % em357_info->ppage_size) != 0) {
        LOG_WARNING("aligned start protect sector to a %d sector boundary",
            em357_info->ppage_size);
        first = first - (first % em357_info->ppage_size);
    }
    if (((last + 1) % em357_info->ppage_size) != 0) {
        LOG_WARNING("aligned end protect sector to a %d sector boundary",
            em357_info->ppage_size);
        last++;
        last = last - (last % em357_info->ppage_size);
        last--;
    }
 
    /* each bit refers to a 4bank protection */
    int retval = target_read_u32(target, EM357_FLASH_WRPR, &protection);
    if (retval != ERROR_OK)
        return retval;
 
    prot_reg[0] = (uint16_t)protection;
    prot_reg[1] = (uint16_t)(protection >> 8);
    prot_reg[2] = (uint16_t)(protection >> 16);
 
    for (unsigned int i = first; i <= last; i++) {
        reg = (i / em357_info->ppage_size) / 8;
        bit = (i / em357_info->ppage_size) - (reg * 8);
 
        LOG_WARNING("reg, bit: %d, %d", reg, bit);
        if (set)
            prot_reg[reg] &= ~(1 << bit);
        else
            prot_reg[reg] |= (1 << bit);
    }
 
    status = em357_erase_options(bank);
    if (retval != ERROR_OK)
        return status;
 
    em357_info->option_bytes.protection[0] = prot_reg[0];
    em357_info->option_bytes.protection[1] = prot_reg[1];
    em357_info->option_bytes.protection[2] = prot_reg[2];
 
    return em357_write_options(bank);
}
 
static int em357_write_block(struct flash_bank *bank, const uint8_t *buffer,
    uint32_t offset, uint32_t count)
{
    struct target *target = bank->target;
    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[4];
    struct armv7m_algorithm armv7m_info;
    int retval = ERROR_OK;
 
    /* see contrib/loaders/flash/stm32x.s for src, the same is used here except for
     * a modified *_FLASH_BASE */
 
    static const uint8_t em357_flash_write_code[] = {
        /* #define EM357_FLASH_CR_OFFSET    0x10
         * #define EM357_FLASH_SR_OFFSET    0x0C
         * write: */
        0x08, 0x4c,                 /* ldr  r4, EM357_FLASH_BASE */
        0x1c, 0x44,                 /* add  r4, r3 */
        /* write_half_word: */
        0x01, 0x23,                 /* movs r3, #0x01 */
        0x23, 0x61,                 /* str  r3, [r4,
                                 *#EM357_FLASH_CR_OFFSET] */
        0x30, 0xf8, 0x02, 0x3b,     /* ldrh r3, [r0], #0x02 */
        0x21, 0xf8, 0x02, 0x3b,     /* strh r3, [r1], #0x02 */
        /* busy: */
        0xe3, 0x68,                 /* ldr  r3, [r4,
                                 *#EM357_FLASH_SR_OFFSET] */
        0x13, 0xf0, 0x01, 0x0f,     /* tst  r3, #0x01 */
        0xfb, 0xd0,                 /* beq  busy */
        0x13, 0xf0, 0x14, 0x0f,     /* tst  r3, #0x14 */
        0x01, 0xd1,                 /* bne  exit */
        0x01, 0x3a,                 /* subs r2, r2, #0x01 */
        0xf0, 0xd1,                 /* bne  write_half_word */
        /* exit: */
        0x00, 0xbe,                 /* bkpt #0x00 */
        0x00, 0x80, 0x00, 0x40,     /* EM357_FLASH_BASE: .word 0x40008000 */
    };
 
    /* flash write code */
    if (target_alloc_working_area(target, sizeof(em357_flash_write_code),
            &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, write_algorithm->address,
            sizeof(em357_flash_write_code), em357_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) {
            /* 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);
    init_reg_param(&reg_params[3], "r3", 32, PARAM_IN_OUT);
 
    while (count > 0) {
        uint32_t thisrun_count = (count > (buffer_size / 2)) ?
            (buffer_size / 2) : count;
 
        retval = target_write_buffer(target, source->address, thisrun_count * 2, buffer);
        if (retval != ERROR_OK)
            break;
 
        buf_set_u32(reg_params[0].value, 0, 32, source->address);
        buf_set_u32(reg_params[1].value, 0, 32, address);
        buf_set_u32(reg_params[2].value, 0, 32, thisrun_count);
        buf_set_u32(reg_params[3].value, 0, 32, 0);
 
        retval = target_run_algorithm(target, 0, NULL, 4, reg_params,
                write_algorithm->address, 0, 10000, &armv7m_info);
        if (retval != ERROR_OK) {
            LOG_ERROR("error executing em357 flash write algorithm");
            break;
        }
 
        if (buf_get_u32(reg_params[3].value, 0, 32) & FLASH_PGERR) {
            LOG_ERROR("flash memory not erased before writing");
            /* Clear but report errors */
            target_write_u32(target, EM357_FLASH_SR, FLASH_PGERR);
            retval = ERROR_FAIL;
            break;
        }
 
        if (buf_get_u32(reg_params[3].value, 0, 32) & FLASH_WRPRTERR) {
            LOG_ERROR("flash memory write protected");
            /* Clear but report errors */
            target_write_u32(target, EM357_FLASH_SR, FLASH_WRPRTERR);
            retval = ERROR_FAIL;
            break;
        }
 
        buffer += thisrun_count * 2;
        address += thisrun_count * 2;
        count -= thisrun_count;
    }
 
    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]);
    destroy_reg_param(&reg_params[3]);
 
    return retval;
}
 
static int em357_write(struct flash_bank *bank, const 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;
    }
 
    /* unlock flash registers */
    retval = target_write_u32(target, EM357_FLASH_KEYR, KEY1);
    if (retval != ERROR_OK)
        return retval;
    retval = target_write_u32(target, EM357_FLASH_KEYR, KEY2);
    if (retval != ERROR_OK)
        return retval;
 
    target_write_u32(target, EM357_FPEC_CLK, 0x00000001);
 
    /* multiple half words (2-byte) to be programmed? */
    if (words_remaining > 0) {
        /* try using a block write */
        retval = em357_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;
 
    while (words_remaining > 0) {
        uint16_t value;
        memcpy(&value, buffer + bytes_written, sizeof(uint16_t));
 
        retval = target_write_u32(target, EM357_FLASH_CR, FLASH_PG);
        if (retval != ERROR_OK)
            return retval;
        retval = target_write_u16(target, address, value);
        if (retval != ERROR_OK)
            return retval;
 
        retval = em357_wait_status_busy(bank, 5);
        if (retval != ERROR_OK)
            return retval;
 
        bytes_written += 2;
        words_remaining--;
        address += 2;
    }
 
    if (bytes_remaining) {
        uint16_t value = 0xffff;
        memcpy(&value, buffer + bytes_written, bytes_remaining);
 
        retval = target_write_u32(target, EM357_FLASH_CR, FLASH_PG);
        if (retval != ERROR_OK)
            return retval;
        retval = target_write_u16(target, address, value);
        if (retval != ERROR_OK)
            return retval;
 
        retval = em357_wait_status_busy(bank, 5);
        if (retval != ERROR_OK)
            return retval;
    }
 
    return target_write_u32(target, EM357_FLASH_CR, FLASH_LOCK);
}
 
static int em357_probe(struct flash_bank *bank)
{
    struct target *target = bank->target;
    struct em357_flash_bank *em357_info = bank->driver_priv;
    int i;
    uint16_t num_pages;
    int page_size;
    uint32_t base_address = 0x08000000;
 
    em357_info->probed = false;
 
    switch (bank->size) {
        case 0x10000:
            /* 64k -- 64 1k pages */
            num_pages = 64;
            page_size = 1024;
            break;
        case 0x20000:
            /* 128k -- 128 1k pages */
            num_pages = 128;
            page_size = 1024;
            break;
        case 0x30000:
            /* 192k -- 96 2k pages */
            num_pages = 96;
            page_size = 2048;
            break;
        case 0x40000:
            /* 256k -- 128 2k pages */
            num_pages = 128;
            page_size = 2048;
            break;
        case 0x80000:
            /* 512k -- 256 2k pages */
            num_pages = 256;
            page_size = 2048;
            break;
        default:
            LOG_WARNING("No size specified for em357 flash driver, assuming 192k!");
            num_pages = 96;
            page_size = 2048;
            break;
    }
 
    /* Enable FPEC CLK */
    int retval = target_write_u32(target, EM357_FPEC_CLK, 0x00000001);
    if (retval != ERROR_OK)
        return retval;
 
    em357_info->ppage_size = 4;
 
    LOG_INFO("flash size = %d KiB", num_pages*page_size/1024);
 
    free(bank->sectors);
 
    bank->base = base_address;
    bank->size = (num_pages * page_size);
    bank->num_sectors = num_pages;
    bank->sectors = malloc(sizeof(struct flash_sector) * num_pages);
 
    for (i = 0; i < num_pages; i++) {
        bank->sectors[i].offset = i * page_size;
        bank->sectors[i].size = page_size;
        bank->sectors[i].is_erased = -1;
        bank->sectors[i].is_protected = 1;
    }
 
    em357_info->probed = true;
 
    return ERROR_OK;
}
 
static int em357_auto_probe(struct flash_bank *bank)
{
    struct em357_flash_bank *em357_info = bank->driver_priv;
    if (em357_info->probed)
        return ERROR_OK;
    return em357_probe(bank);
}
 
COMMAND_HANDLER(em357_handle_lock_command)
{
    struct target *target = NULL;
    struct em357_flash_bank *em357_info = NULL;
 
    if (CMD_ARGC < 1)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    struct flash_bank *bank;
    int retval = CALL_COMMAND_HANDLER(flash_command_get_bank, 0, &bank);
    if (retval != ERROR_OK)
        return retval;
 
    em357_info = bank->driver_priv;
 
    target = bank->target;
 
    if (target->state != TARGET_HALTED) {
        LOG_ERROR("Target not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    if (em357_erase_options(bank) != ERROR_OK) {
        command_print(CMD, "em357 failed to erase options");
        return ERROR_OK;
    }
 
    /* set readout protection */
    em357_info->option_bytes.RDP = 0;
 
    if (em357_write_options(bank) != ERROR_OK) {
        command_print(CMD, "em357 failed to lock device");
        return ERROR_OK;
    }
 
    command_print(CMD, "em357 locked");
 
    return ERROR_OK;
}
 
COMMAND_HANDLER(em357_handle_unlock_command)
{
    struct target *target = NULL;
 
    if (CMD_ARGC < 1)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    struct flash_bank *bank;
    int retval = CALL_COMMAND_HANDLER(flash_command_get_bank, 0, &bank);
    if (retval != ERROR_OK)
        return retval;
 
    target = bank->target;
 
    if (target->state != TARGET_HALTED) {
        LOG_ERROR("Target not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    if (em357_erase_options(bank) != ERROR_OK) {
        command_print(CMD, "em357 failed to unlock device");
        return ERROR_OK;
    }
 
    if (em357_write_options(bank) != ERROR_OK) {
        command_print(CMD, "em357 failed to lock device");
        return ERROR_OK;
    }
 
    command_print(CMD, "em357 unlocked.\n"
        "INFO: a reset or power cycle is required "
        "for the new settings to take effect.");
 
    return ERROR_OK;
}
 
static int em357_mass_erase(struct flash_bank *bank)
{
    struct target *target = bank->target;
 
    if (target->state != TARGET_HALTED) {
        LOG_ERROR("Target not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    /* Make sure the flash clock is on */
    target_write_u32(target, EM357_FPEC_CLK, 0x00000001);
 
    /* unlock option flash registers */
    int retval = target_write_u32(target, EM357_FLASH_KEYR, KEY1);
    if (retval != ERROR_OK)
        return retval;
    retval = target_write_u32(target, EM357_FLASH_KEYR, KEY2);
    if (retval != ERROR_OK)
        return retval;
 
    /* mass erase flash memory */
    retval = target_write_u32(target, EM357_FLASH_CR, FLASH_MER);
    if (retval != ERROR_OK)
        return retval;
    retval = target_write_u32(target, EM357_FLASH_CR, FLASH_MER | FLASH_STRT);
    if (retval != ERROR_OK)
        return retval;
 
    retval = em357_wait_status_busy(bank, 100);
    if (retval != ERROR_OK)
        return retval;
 
    retval = target_write_u32(target, EM357_FLASH_CR, FLASH_LOCK);
    if (retval != ERROR_OK)
        return retval;
 
    return ERROR_OK;
}
 
COMMAND_HANDLER(em357_handle_mass_erase_command)
{
    if (CMD_ARGC < 1)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    struct flash_bank *bank;
    int retval = CALL_COMMAND_HANDLER(flash_command_get_bank, 0, &bank);
    if (retval != ERROR_OK)
        return retval;
 
    retval = em357_mass_erase(bank);
    if (retval == ERROR_OK)
        command_print(CMD, "em357 mass erase complete");
    else
        command_print(CMD, "em357 mass erase failed");
 
    return retval;
}
 
static const struct command_registration em357_exec_command_handlers[] = {
    {
        .name = "lock",
        .usage = "<bank>",
        .handler = em357_handle_lock_command,
        .mode = COMMAND_EXEC,
        .help = "Lock entire flash device.",
    },
    {
        .name = "unlock",
        .usage = "<bank>",
        .handler = em357_handle_unlock_command,
        .mode = COMMAND_EXEC,
        .help = "Unlock entire protected flash device.",
    },
    {
        .name = "mass_erase",
        .usage = "<bank>",
        .handler = em357_handle_mass_erase_command,
        .mode = COMMAND_EXEC,
        .help = "Erase entire flash device.",
    },
    COMMAND_REGISTRATION_DONE
};
 
static const struct command_registration em357_command_handlers[] = {
    {
        .name = "em357",
        .mode = COMMAND_ANY,
        .help = "em357 flash command group",
        .usage = "",
        .chain = em357_exec_command_handlers,
    },
    COMMAND_REGISTRATION_DONE
};
 
const struct flash_driver em357_flash = {
    .name = "em357",
    .commands = em357_command_handlers,
    .flash_bank_command = em357_flash_bank_command,
    .erase = em357_erase,
    .protect = em357_protect,
    .write = em357_write,
    .read = default_flash_read,
    .probe = em357_probe,
    .auto_probe = em357_auto_probe,
    .erase_check = default_flash_blank_check,
    .protect_check = em357_protect_check,
    .free_driver_priv = default_flash_free_driver_priv,
};