flash: New driver for XMC4xxx microcontroller family

[openocd.git] / src / flash / nor / xmc4xxx.c

/**************************************************************************
*   Copyright (C) 2015 Jeff Ciesielski <jeffciesielski@gmail.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.                          *
*                                                                         *
***************************************************************************/

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

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

/* Maximum number of sectors */
#define MAX_XMC_SECTORS 12

/* System control unit registers */
#define SCU_REG_BASE 0x50004000

#define SCU_ID_CHIP 0x04

/* Base of the non-cached flash memory */
#define PFLASH_BASE     0x0C000000

/* User configuration block offsets */
#define UCB0_BASE       0x00000000
#define UCB1_BASE       0x00000400
#define UCB2_BASE       0x00000800

/* Flash register base */
#define FLASH_REG_BASE 0x58000000

/* PMU ID Registers */
#define FLASH_REG_PMU_ID        (FLASH_REG_BASE | 0x0508)

/* PMU Fields */
#define PMU_MOD_REV_MASK        0xFF
#define PMU_MOD_TYPE_MASK       0xFF00
#define PMU_MOD_NO_MASK         0xFFFF0000

/* Prefetch Config */
#define FLASH_REG_PREF_PCON     (FLASH_REG_BASE | 0x4000)

/* Prefetch Fields */
#define PCON_IBYP       (1 << 0)
#define PCON_IINV       (1 << 1)

/* Flash ID Register */
#define FLASH_REG_FLASH0_ID     (FLASH_REG_BASE | 0x2008)

/* Flash Status Register */
#define FLASH_REG_FLASH0_FSR    (FLASH_REG_BASE | 0x2010)

#define FSR_PBUSY       (0)
#define FSR_FABUSY      (1)
#define FSR_PROG        (4)
#define FSR_ERASE       (5)
#define FSR_PFPAGE      (6)
#define FSR_PFOPER      (8)
#define FSR_SQER        (10)
#define FSR_PROER       (11)
#define FSR_PFSBER      (12)
#define FSR_PFDBER      (14)
#define FSR_PROIN       (16)
#define FSR_RPROIN      (18)
#define FSR_RPRODIS     (19)
#define FSR_WPROIN0     (21)
#define FSR_WPROIN1     (22)
#define FSR_WPROIN2     (23)
#define FSR_WPRODIS0    (25)
#define FSR_WPRODIS1    (26)
#define FSR_SLM         (28)
#define FSR_VER         (31)

#define FSR_PBUSY_MASK          (0x01 << FSR_PBUSY)
#define FSR_FABUSY_MASK         (0x01 << FSR_FABUSY)
#define FSR_PROG_MASK           (0x01 << FSR_PROG)
#define FSR_ERASE_MASK          (0x01 << FSR_ERASE)
#define FSR_PFPAGE_MASK         (0x01 << FSR_PFPAGE)
#define FSR_PFOPER_MASK         (0x01 << FSR_PFOPER)
#define FSR_SQER_MASK           (0x01 << FSR_SQER)
#define FSR_PROER_MASK          (0x01 << FSR_PROER)
#define FSR_PFSBER_MASK         (0x01 << FSR_PFSBER)
#define FSR_PFDBER_MASK         (0x01 << FSR_PFDBER)
#define FSR_PROIN_MASK          (0x01 << FSR_PROIN)
#define FSR_RPROIN_MASK         (0x01 << FSR_RPROIN)
#define FSR_RPRODIS_MASK        (0x01 << FSR_RPRODIS)
#define FSR_WPROIN0_MASK        (0x01 << FSR_WPROIN0)
#define FSR_WPROIN1_MASK        (0x01 << FSR_WPROIN1)
#define FSR_WPROIN2_MASK        (0x01 << FSR_WPROIN2)
#define FSR_WPRODIS0_MASK       (0x01 << FSR_WPRODIS0)
#define FSR_WPRODIS1_MASK       (0x01 << FSR_WPRODIS1)
#define FSR_SLM_MASK            (0x01 << FSR_SLM)
#define FSR_VER_MASK            (0x01 << FSR_VER)

/* Flash Config Register */
#define FLASH_REG_FLASH0_FCON   (FLASH_REG_BASE | 0x2014)

#define FCON_WSPFLASH           (0)
#define FCON_WSECPF             (4)
#define FCON_IDLE               (13)
#define FCON_ESLDIS             (14)
#define FCON_SLEEP              (15)
#define FCON_RPA                (16)
#define FCON_DCF                (17)
#define FCON_DDF                (18)
#define FCON_VOPERM             (24)
#define FCON_SQERM              (25)
#define FCON_PROERM             (26)
#define FCON_PFSBERM            (27)
#define FCON_PFDBERM            (29)
#define FCON_EOBM               (31)

#define FCON_WSPFLASH_MASK      (0x0f << FCON_WSPFLASH)
#define FCON_WSECPF_MASK        (0x01 << FCON_WSECPF)
#define FCON_IDLE_MASK          (0x01 << FCON_IDLE)
#define FCON_ESLDIS_MASK        (0x01 << FCON_ESLDIS)
#define FCON_SLEEP_MASK         (0x01 << FCON_SLEEP)
#define FCON_RPA_MASK           (0x01 << FCON_RPA)
#define FCON_DCF_MASK           (0x01 << FCON_DCF)
#define FCON_DDF_MASK           (0x01 << FCON_DDF)
#define FCON_VOPERM_MASK        (0x01 << FCON_VOPERM)
#define FCON_SQERM_MASK         (0x01 << FCON_SQERM)
#define FCON_PROERM_MASK        (0x01 << FCON_PROERM)
#define FCON_PFSBERM_MASK       (0x01 << FCON_PFSBERM)
#define FCON_PFDBERM_MASK       (0x01 << FCON_PFDBERM)
#define FCON_EOBM_MASK          (0x01 << FCON_EOBM)

/* Flash Margin Control Register */
#define FLASH_REG_FLASH0_MARP   (FLASH_REG_BASE | 0x2018)

#define MARP_MARGIN             (0)
#define MARP_TRAPDIS            (15)

#define MARP_MARGIN_MASK        (0x0f << MARP_MARGIN)
#define MARP_TRAPDIS_MASK       (0x01 << MARP_TRAPDIS)

/* Flash Protection Registers */
#define FLASH_REG_FLASH0_PROCON0        (FLASH_REG_BASE | 0x2020)
#define FLASH_REG_FLASH0_PROCON1        (FLASH_REG_BASE | 0x2024)
#define FLASH_REG_FLASH0_PROCON2        (FLASH_REG_BASE | 0x2028)

#define PROCON_S0L             (0)
#define PROCON_S1L             (1)
#define PROCON_S2L             (2)
#define PROCON_S3L             (3)
#define PROCON_S4L             (4)
#define PROCON_S5L             (5)
#define PROCON_S6L             (6)
#define PROCON_S7L             (7)
#define PROCON_S8L             (8)
#define PROCON_S9L             (9)
#define PROCON_S10_S11L        (10)
#define PROCON_RPRO            (15)

#define PROCON_S0L_MASK        (0x01 << PROCON_S0L)
#define PROCON_S1L_MASK        (0x01 << PROCON_S1L)
#define PROCON_S2L_MASK        (0x01 << PROCON_S2L)
#define PROCON_S3L_MASK        (0x01 << PROCON_S3L)
#define PROCON_S4L_MASK        (0x01 << PROCON_S4L)
#define PROCON_S5L_MASK        (0x01 << PROCON_S5L)
#define PROCON_S6L_MASK        (0x01 << PROCON_S6L)
#define PROCON_S7L_MASK        (0x01 << PROCON_S7L)
#define PROCON_S8L_MASK        (0x01 << PROCON_S8L)
#define PROCON_S9L_MASK        (0x01 << PROCON_S9L)
#define PROCON_S10_S11L_MASK   (0x01 << PROCON_S10_S11L)
#define PROCON_RPRO_MASK       (0x01 << PROCON_RPRO)

#define FLASH_PROTECT_CONFIRMATION_CODE 0x8AFE15C3

/* Flash controller configuration values */
#define FLASH_ID_XMC4500        0xA2
#define FLASH_ID_XMC4100_4200   0x9C
#define FLASH_ID_XMC4400        0x9F

/* Timeouts */
#define FLASH_OP_TIMEOUT 5000

/* Flash commands (write/erase/protect) are performed using special
 * command sequences that are written to magic addresses in the flash controller */
/* Command sequence addresses.  See reference manual, section 8: Flash Command Sequences */
#define FLASH_CMD_ERASE_1 0x0C005554
#define FLASH_CMD_ERASE_2 0x0C00AAA8
#define FLASH_CMD_ERASE_3 FLASH_CMD_ERASE_1
#define FLASH_CMD_ERASE_4 FLASH_CMD_ERASE_1
#define FLASH_CMD_ERASE_5 FLASH_CMD_ERASE_2
/* ERASE_6 is the sector base address */

#define FLASH_CMD_CLEAR_STATUS FLASH_CMD_ERASE_1

#define FLASH_CMD_ENTER_PAGEMODE FLASH_CMD_ERASE_1

#define FLASH_CMD_LOAD_PAGE_1 0x0C0055F0
#define FLASH_CMD_LOAD_PAGE_2 0x0C0055F4

#define FLASH_CMD_WRITE_PAGE_1 FLASH_CMD_ERASE_1
#define FLASH_CMD_WRITE_PAGE_2 FLASH_CMD_ERASE_2
#define FLASH_CMD_WRITE_PAGE_3 FLASH_CMD_ERASE_1
/* WRITE_PAGE_4 is the page base address */

#define FLASH_CMD_TEMP_UNPROT_1 FLASH_CMD_ERASE_1
#define FLASH_CMD_TEMP_UNPROT_2 FLASH_CMD_ERASE_2
#define FLASH_CMD_TEMP_UNPROT_3 0x0C00553C
#define FLASH_CMD_TEMP_UNPROT_4 FLASH_CMD_ERASE_2
#define FLASH_CMD_TEMP_UNPROT_5 FLASH_CMD_ERASE_2
#define FLASH_CMD_TEMP_UNPROT_6 0x0C005558

struct xmc4xxx_flash_bank {
        bool probed;

        /* We need the flash controller ID to choose the sector layout */
        uint32_t fcon_id;

        /* Passwords used for protection operations */
        uint32_t pw1;
        uint32_t pw2;
        bool pw_set;

        /* Protection flags */
        bool read_protected;

        bool write_prot_otp[MAX_XMC_SECTORS];
};

struct xmc4xxx_command_seq {
        uint32_t address;
        uint32_t magic;
};

/* Sector capacities.  See section 8 of xmc4x00_rm */
static unsigned int sector_capacity_8[] = {
        16, 16, 16, 16, 16, 16, 16, 128
};

static unsigned int sector_capacity_9[] = {
        16, 16, 16, 16, 16, 16, 16, 128, 256
};

static unsigned int sector_capacity_12[] = {
        16, 16, 16, 16, 16, 16, 16, 16, 128, 256, 256, 256
};

static int xmc4xxx_write_command_sequence(struct flash_bank *bank,
                                         struct xmc4xxx_command_seq *seq,
                                         int seq_len)
{
        int res = ERROR_OK;

        for (int i = 0; i < seq_len; i++) {
                res = target_write_u32(bank->target, seq[i].address,
                                       seq[i].magic);
                if (res != ERROR_OK)
                        return res;
        }

        return ERROR_OK;
}

static int xmc4xxx_load_bank_layout(struct flash_bank *bank)
{
        unsigned int *capacity = NULL;

        /* At this point, we know which flash controller ID we're
         * talking to and simply need to fill out the bank structure accordingly */
        LOG_DEBUG("%d sectors", bank->num_sectors);

        switch (bank->num_sectors) {
        case 8:
                capacity = sector_capacity_8;
                break;
        case 9:
                capacity = sector_capacity_9;
                break;
        case 12:
                capacity = sector_capacity_12;
                break;
        default:
                LOG_ERROR("Unexpected number of sectors, %d\n",
                          bank->num_sectors);
                return ERROR_FAIL;
        }

        /* This looks like a bank that we understand, now we know the
         * corresponding sector capacities and we can add those up into the
         * bank size. */
        uint32_t total_offset = 0;
        bank->sectors = calloc(bank->num_sectors,
                               sizeof(struct flash_sector));
        for (int i = 0; i < bank->num_sectors; i++) {
                bank->sectors[i].size = capacity[i] * 1024;
                bank->sectors[i].offset = total_offset;
                bank->sectors[i].is_erased = -1;
                bank->sectors[i].is_protected = -1;

                bank->size += bank->sectors[i].size;
                LOG_DEBUG("\t%d: %uk", i, capacity[i]);
                total_offset += bank->sectors[i].size;
        }

        /* This part doesn't follow the typical standard of 0xff
         * being the default padding value.*/
        bank->default_padded_value = 0x00;

        return ERROR_OK;
}

static int xmc4xxx_probe(struct flash_bank *bank)
{
        int res;
        uint32_t devid, config;
        struct xmc4xxx_flash_bank *fb = bank->driver_priv;
        uint8_t flash_id;

        if (fb->probed)
                return ERROR_OK;

        /* It's not possible for the DAP to access the OTP locations needed for
         * probing the part info and Flash geometry so we require that the target
         * be halted before proceeding. */
        if (bank->target->state != TARGET_HALTED) {
                LOG_WARNING("Cannot communicate... target not halted.");
                return ERROR_TARGET_NOT_HALTED;
        }

        /* The SCU registers contain the ID of the chip */
        res = target_read_u32(bank->target, SCU_REG_BASE + SCU_ID_CHIP, &devid);
        if (res != ERROR_OK) {
                LOG_ERROR("Cannot read device identification register.");
                return res;
        }

        /* Make sure this is a XMC4000 family device */
        if ((devid & 0xF0000) != 0x40000) {
                LOG_ERROR("Platform ID doesn't match XMC4xxx: 0x%08" PRIx32, devid);
                return ERROR_FAIL;
        }

        LOG_DEBUG("Found XMC4xxx with devid: 0x%08" PRIx32, devid);

        /* Now sanity-check the Flash controller itself. */
        res = target_read_u32(bank->target, FLASH_REG_FLASH0_ID,
                        &config);
        if (res != ERROR_OK) {
                LOG_ERROR("Cannot read Flash bank configuration.");
                return res;
        }
        flash_id = (config & 0xff0000) >> 16;

        /* The Flash configuration register is our only means of
         * determining the sector layout. We need to make sure that
         * we understand the type of controller we're dealing with */
        switch (flash_id) {
        case FLASH_ID_XMC4100_4200:
                bank->num_sectors = 8;
                LOG_DEBUG("XMC4xxx: XMC4100/4200 detected.");
                break;
        case FLASH_ID_XMC4400:
                bank->num_sectors = 9;
                LOG_DEBUG("XMC4xxx: XMC4400 detected.");
                break;
        case FLASH_ID_XMC4500:
                bank->num_sectors = 12;
                LOG_DEBUG("XMC4xxx: XMC4500 detected.");
                break;
        default:
                LOG_ERROR("XMC4xxx: Unexpected flash ID. got %02" PRIx8,
                          flash_id);
                return ERROR_FAIL;
        }

        /* Retrieve information about the particular bank we're probing and fill in
         * the bank structure accordingly. */
        res = xmc4xxx_load_bank_layout(bank);
        if (res == ERROR_OK) {
                /* We're done */
                fb->probed = true;
        } else {
                LOG_ERROR("Unable to load bank information.");
                return ERROR_FAIL;
        }

        return ERROR_OK;
}

static int xmc4xxx_get_sector_start_addr(struct flash_bank *bank,
                                         int sector, uint32_t *ret_addr)
{
        /* Make sure we understand this sector */
        if (sector > bank->num_sectors)
                return ERROR_FAIL;

        *ret_addr = bank->base + bank->sectors[sector].offset;

        return ERROR_OK;

}

static int xmc4xxx_clear_flash_status(struct flash_bank *bank)
{
        int res;
        /* TODO: Do we need to check for sequence error? */
        LOG_INFO("Clearing flash status");
        res = target_write_u32(bank->target, FLASH_CMD_CLEAR_STATUS,
                               0xF5);
        if (res != ERROR_OK) {
                LOG_ERROR("Unable to write erase command sequence");
                return res;
        }

        return ERROR_OK;
}

static int xmc4xxx_get_flash_status(struct flash_bank *bank, uint32_t *status)
{
        int res;

        res = target_read_u32(bank->target, FLASH_REG_FLASH0_FSR, status);

        if (res != ERROR_OK)
                LOG_ERROR("Cannot read flash status register.");

        return res;
}

static int xmc4xxx_wait_status_busy(struct flash_bank *bank, int timeout)
{
        int res;
        uint32_t status;

        res = xmc4xxx_get_flash_status(bank, &status);
        if (res != ERROR_OK)
                return res;

        /* While the flash controller is busy, wait */
        while (status & FSR_PBUSY_MASK) {
                res = xmc4xxx_get_flash_status(bank, &status);
                if (res != ERROR_OK)
                        return res;

                if (timeout-- <= 0) {
                        LOG_ERROR("Timed out waiting for flash");
                        return ERROR_FAIL;
                }
                alive_sleep(1);
                keep_alive();
        }

        if (status & FSR_PROER_MASK) {
                LOG_ERROR("XMC4xxx flash protected");
                res = ERROR_FAIL;
        }

        return res;
}

static int xmc4xxx_erase_sector(struct flash_bank *bank, uint32_t address,
                                bool user_config)
{
        int res;
        uint32_t status;

        /* See reference manual table 8.4: Command Sequences for Flash Control */
        struct xmc4xxx_command_seq erase_cmd_seq[6] = {
                {FLASH_CMD_ERASE_1, 0xAA},
                {FLASH_CMD_ERASE_2, 0x55},
                {FLASH_CMD_ERASE_3, 0x80},
                {FLASH_CMD_ERASE_4, 0xAA},
                {FLASH_CMD_ERASE_5, 0x55},
                {0xFF,              0xFF} /* Needs filled in */
        };

        /* We need to fill in the base address of the sector we'll be
         * erasing, as well as the magic code that determines whether
         * this is a standard flash sector or a user configuration block */

        erase_cmd_seq[5].address = address;
        if (user_config) {
                /* Removing flash protection requires the addition of
                 * the base address */
                erase_cmd_seq[5].address += bank->base;
                erase_cmd_seq[5].magic = 0xC0;
        } else {
                erase_cmd_seq[5].magic = 0x30;
        }

        res = xmc4xxx_write_command_sequence(bank, erase_cmd_seq,
                                             ARRAY_SIZE(erase_cmd_seq));
        if (res != ERROR_OK)
                return res;

        /* Read the flash status register */
        res = target_read_u32(bank->target, FLASH_REG_FLASH0_FSR, &status);
        if (res != ERROR_OK) {
                LOG_ERROR("Cannot read flash status register.");
                return res;
        }

        /* Check for a sequence error */
        if (status & FSR_SQER_MASK) {
                LOG_ERROR("Error with flash erase sequence");
                return ERROR_FAIL;
        }

        /* Make sure a flash erase was triggered */
        if (!(status & FSR_ERASE_MASK)) {
                LOG_ERROR("Flash failed to erase");
                return ERROR_FAIL;
        }

        /* Now we must wait for the erase operation to end */
        res = xmc4xxx_wait_status_busy(bank, FLASH_OP_TIMEOUT);

        return res;
}

static int xmc4xxx_erase(struct flash_bank *bank, int first, int last)
{
        struct xmc4xxx_flash_bank *fb = bank->driver_priv;
        int res;

        if (bank->target->state != TARGET_HALTED) {
                LOG_ERROR("Unable to erase, target is not halted");
                return ERROR_TARGET_NOT_HALTED;
        }

        if (!fb->probed) {
                res = xmc4xxx_probe(bank);
                if (res != ERROR_OK)
                        return res;
        }

        uint32_t tmp_addr;
        /* Loop through the sectors and erase each one */
        for (int i = first; i <= last; i++) {
                res = xmc4xxx_get_sector_start_addr(bank, i, &tmp_addr);
                if (res != ERROR_OK) {
                        LOG_ERROR("Invalid sector %d", i);
                        return res;
                }

                LOG_DEBUG("Erasing sector %d @ 0x%08"PRIx32, i, tmp_addr);

                res = xmc4xxx_erase_sector(bank, tmp_addr, false);
                if (res != ERROR_OK) {
                        LOG_ERROR("Unable to write erase command sequence");
                        goto clear_status_and_exit;
                }

                /* Now we must wait for the erase operation to end */
                res = xmc4xxx_wait_status_busy(bank, FLASH_OP_TIMEOUT);

                if (res != ERROR_OK)
                        goto clear_status_and_exit;

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

clear_status_and_exit:
        res = xmc4xxx_clear_flash_status(bank);
        return res;

}

static int xmc4xxx_enter_page_mode(struct flash_bank *bank)
{
        int res;
        uint32_t status;

        res = target_write_u32(bank->target, FLASH_CMD_ENTER_PAGEMODE, 0x50);
        if (res != ERROR_OK) {
                LOG_ERROR("Unable to write enter page mode command");
                return ERROR_FAIL;
        }

        res = xmc4xxx_get_flash_status(bank, &status);

        if (res != ERROR_OK)
                return res;

        /* Make sure we're in page mode */
        if (!(status & FSR_PFPAGE_MASK)) {
                LOG_ERROR("Unable to enter page mode");
                return ERROR_FAIL;
        }

        /* Make sure we didn't encounter a sequence error */
        if (status & FSR_SQER_MASK) {
                LOG_ERROR("Sequence error while entering page mode");
                return ERROR_FAIL;
        }

        return res;
}

/* The logical erase value of an xmc4xxx memory cell is 0x00,
 * therefore, we cannot use the built in flash blank check and must
 * implement our own */

/** Checks whether a memory region is zeroed. */
int xmc4xxx_blank_check_memory(struct target *target,
        uint32_t address, uint32_t count, uint32_t *blank)
{
        struct working_area *erase_check_algorithm;
        struct reg_param reg_params[3];
        struct armv7m_algorithm armv7m_info;
        int retval;

        /* see contrib/loaders/erase_check/armv7m_0_erase_check.s for src */

        static const uint8_t erase_check_code[] = {
                /* loop: */
                0x03, 0x78,             /* ldrb r3, [r0] */
                0x01, 0x30,             /* adds r0, #1 */
                0x1A, 0x43,             /* orrs r2, r2, r3 */
                0x01, 0x39,             /* subs r1, r1, #1 */
                0xFA, 0xD1,             /* bne  loop */
                0x00, 0xBE              /* bkpt #0 */
        };

        /* make sure we have a working area */
        if (target_alloc_working_area(target, sizeof(erase_check_code),
                &erase_check_algorithm) != ERROR_OK)
                return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;

        retval = target_write_buffer(target, erase_check_algorithm->address,
                        sizeof(erase_check_code), (uint8_t *)erase_check_code);
        if (retval != ERROR_OK)
                return retval;

        armv7m_info.common_magic = ARMV7M_COMMON_MAGIC;
        armv7m_info.core_mode = ARM_MODE_THREAD;

        init_reg_param(&reg_params[0], "r0", 32, PARAM_OUT);
        buf_set_u32(reg_params[0].value, 0, 32, address);

        init_reg_param(&reg_params[1], "r1", 32, PARAM_OUT);
        buf_set_u32(reg_params[1].value, 0, 32, count);

        init_reg_param(&reg_params[2], "r2", 32, PARAM_IN_OUT);
        buf_set_u32(reg_params[2].value, 0, 32, 0x00);

        retval = target_run_algorithm(target,
                                      0,
                                      NULL,
                                      3,
                                      reg_params,
                                      erase_check_algorithm->address,
                                      erase_check_algorithm->address + (sizeof(erase_check_code) - 2),
                                      10000,
                                      &armv7m_info);

        if (retval == ERROR_OK)
                *blank = buf_get_u32(reg_params[2].value, 0, 32);

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

        target_free_working_area(target, erase_check_algorithm);

        return retval;
}

static int xmc4xxx_flash_blank_check(struct flash_bank *bank)
{
        struct target *target = bank->target;
        int i;
        int retval;
        uint32_t blank;

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

        for (i = 0; i < bank->num_sectors; i++) {
                uint32_t address = bank->base + bank->sectors[i].offset;
                uint32_t size = bank->sectors[i].size;

                LOG_DEBUG("Erase checking 0x%08"PRIx32, address);
                retval = xmc4xxx_blank_check_memory(target, address, size, &blank);

                if (retval != ERROR_OK)
                        break;

                if (blank == 0x00)
                        bank->sectors[i].is_erased = 1;
                else
                        bank->sectors[i].is_erased = 0;
        }

        return ERROR_OK;
}

static int xmc4xxx_write_page(struct flash_bank *bank, const uint8_t *pg_buf,
                              uint32_t offset, bool user_config)
{
        int res;
        uint32_t status;

        /* Base of the flash write command */
        struct xmc4xxx_command_seq write_cmd_seq[4] = {
                {FLASH_CMD_WRITE_PAGE_1, 0xAA},
                {FLASH_CMD_WRITE_PAGE_2, 0x55},
                {FLASH_CMD_WRITE_PAGE_3, 0xFF}, /* Needs filled in */
                {0xFF,                   0xFF}  /* Needs filled in */
        };

        /* The command sequence differs depending on whether this is
         * being written to standard flash or the user configuration
         * area */
        if (user_config)
                write_cmd_seq[2].magic = 0xC0;
        else
                write_cmd_seq[2].magic = 0xA0;

        /* Finally, we need to add the address that this page will be
         * written to */
        write_cmd_seq[3].address = bank->base + offset;
        write_cmd_seq[3].magic = 0xAA;


        /* Flash pages are written 256 bytes at a time.  For each 256
         * byte chunk, we need to:
         * 1. Enter page mode. This activates the flash write buffer
         * 2. Load the page buffer with data (2x 32 bit words at a time)
         * 3. Burn the page buffer into its intended location
         * If the starting offset is not on a 256 byte boundary, we
         * will need to pad the beginning of the write buffer
         * accordingly. Likewise, if the last page does not fill the
         * buffer, we should pad it to avoid leftover data from being
         * written to flash
         */
        res = xmc4xxx_enter_page_mode(bank);
        if (res != ERROR_OK)
                return res;

        /* Copy the data into the page buffer*/
        for (int i = 0; i < 256; i += 8) {
                uint32_t w_lo = target_buffer_get_u32(bank->target, &pg_buf[i]);
                uint32_t w_hi = target_buffer_get_u32(bank->target, &pg_buf[i + 4]);
                LOG_DEBUG("WLO: %08"PRIx32, w_lo);
                LOG_DEBUG("WHI: %08"PRIx32, w_hi);

                /* Data is loaded 2x 32 bit words at a time */
                res = target_write_u32(bank->target, FLASH_CMD_LOAD_PAGE_1, w_lo);
                if (res != ERROR_OK)
                        return res;

                res = target_write_u32(bank->target, FLASH_CMD_LOAD_PAGE_2, w_hi);
                if (res != ERROR_OK)
                        return res;

                /* Check for an error */
                res = xmc4xxx_get_flash_status(bank, &status);
                if (res != ERROR_OK)
                        return res;

                if (status & FSR_SQER_MASK) {
                        LOG_ERROR("Error loading page buffer");
                        return ERROR_FAIL;
                }
        }

        /* The page buffer is now full, time to commit it to flash */

        res = xmc4xxx_write_command_sequence(bank, write_cmd_seq, ARRAY_SIZE(write_cmd_seq));
        if (res != ERROR_OK) {
                LOG_ERROR("Unable to enter write command sequence");
                return res;
        }

        /* Read the flash status register */
        res = xmc4xxx_get_flash_status(bank, &status);
        if (res != ERROR_OK)
                return res;

        /* Check for a sequence error */
        if (status & FSR_SQER_MASK) {
                LOG_ERROR("Error with flash write sequence");
                return ERROR_FAIL;
        }

        /* Make sure a flash write was triggered */
        if (!(status & FSR_PROG_MASK)) {
                LOG_ERROR("Failed to write flash page");
                return ERROR_FAIL;
        }

        /* Wait for the write operation to end */
        res = xmc4xxx_wait_status_busy(bank, FLASH_OP_TIMEOUT);
        if (res != ERROR_OK)
                return res;

        /* TODO: Verify that page was written without error */
        return res;
}

static int xmc4xxx_write(struct flash_bank *bank, const uint8_t *buffer,
                         uint32_t offset, uint32_t count)
{
        struct xmc4xxx_flash_bank *fb = bank->driver_priv;
        int res = ERROR_OK;

        if (bank->target->state != TARGET_HALTED) {
                LOG_ERROR("Unable to erase, target is not halted");
                return ERROR_TARGET_NOT_HALTED;
        }

        if (!fb->probed) {
                res = xmc4xxx_probe(bank);
                if (res != ERROR_OK)
                        return res;
        }

        /* Make sure we won't run off the end of the flash bank */
        if ((offset + count) > (bank->size)) {
                LOG_ERROR("Attempting to write past the end of flash");
                return ERROR_FAIL;
        }


        /* Attempt to write the passed in buffer to flash */
        /* Pages are written 256 bytes at a time, we need to handle
         * scenarios where padding is required at the beginning and
         * end of a page */
        while (count) {
                /* page working area */
                uint8_t tmp_buf[256] = {0};

                /* Amount of data we'll be writing to this page */
                int remaining;
                int end_pad;

                remaining = MIN(count, sizeof(tmp_buf));
                end_pad   = sizeof(tmp_buf) - remaining;

                /* Make sure we're starting on a page boundary */
                int start_pad = offset % 256;
                if (start_pad) {
                        LOG_INFO("Write does not start on a 256 byte boundary. "
                                 "Padding by %d bytes", start_pad);
                        memset(tmp_buf, 0xff, start_pad);
                        /* Subtract the amount of start offset from
                         * the amount of data we'll need to write */
                        remaining -= start_pad;
                }

                /* Remove the amount we'll be writing from the total count */
                count -= remaining;

                /* Now copy in the remaining data */
                memcpy(&tmp_buf[start_pad], buffer, remaining);

                if (end_pad) {
                        LOG_INFO("Padding end of page @%08"PRIx32" by %d bytes",
                                 bank->base + offset, end_pad);
                        memset(&tmp_buf[256 - end_pad], 0xff, end_pad);
                }

                /* Now commit this page to flash, if there was start
                 * padding, we should subtract that from the target offset */
                res = xmc4xxx_write_page(bank, tmp_buf, (offset - start_pad), false);
                if (res != ERROR_OK) {
                        LOG_ERROR("Unable to write flash page");
                        goto abort_write_and_exit;
                }

                /* Advance the buffer pointer */
                buffer += remaining;

                /* Advance the offset */
                offset += remaining;
        }

abort_write_and_exit:
        xmc4xxx_clear_flash_status(bank);
        return res;

}

static int xmc4xxx_get_info_command(struct flash_bank *bank, char *buf, int buf_size)
{
        struct xmc4xxx_flash_bank *fb = bank->driver_priv;
        uint32_t scu_idcode;

        if (bank->target->state != TARGET_HALTED) {
                LOG_WARNING("Cannot communicate... target not halted.");
                return ERROR_TARGET_NOT_HALTED;
        }

        /* The SCU registers contain the ID of the chip */
        int res = target_read_u32(bank->target, SCU_REG_BASE + SCU_ID_CHIP, &scu_idcode);
        if (res != ERROR_OK) {
                LOG_ERROR("Cannot read device identification register.");
                return res;
        }

        uint16_t dev_id = (scu_idcode & 0xfff0) >> 4;
        uint16_t rev_id = scu_idcode & 0xf;
        const char *dev_str;
        const char *rev_str = NULL;

        switch (dev_id) {
        case 0x100:
                dev_str = "XMC4100";

                switch (rev_id) {
                case 0x1:
                        rev_str = "AA";
                        break;
                case 0x2:
                        rev_str = "AB";
                        break;
                }
                break;
        case 0x200:
                dev_str = "XMC4200";

                switch (rev_id) {
                case 0x1:
                        rev_str = "AA";
                        break;
                case 0x2:
                        rev_str = "AB";
                        break;
                }
                break;
        case 0x400:
                dev_str = "XMC4400";

                switch (rev_id) {
                case 0x1:
                        rev_str = "AA";
                        break;
                case 0x2:
                        rev_str = "AB";
                        break;
                }
                break;
        case 0x500:
                dev_str = "XMC4500";

                switch (rev_id) {
                case 0x2:
                        rev_str = "AA";
                        break;
                case 0x3:
                        rev_str = "AB";
                        break;
                case 0x4:
                        rev_str = "AC";
                        break;
                }
                break;

        default:
                snprintf(buf, buf_size,
                         "Cannot identify target as an XMC4xxx. SCU_ID: %"PRIx32"\n",
                         scu_idcode);
                return ERROR_OK;
        }

        /* String to declare protection data held in the private driver */
        char prot_str[512] = {0};
        if (fb->read_protected)
                snprintf(prot_str, sizeof(prot_str), "\nFlash is read protected");

        bool otp_enabled = false;
        for (int i = 0; i < bank->num_sectors; i++)
                if (fb->write_prot_otp[i])
                        otp_enabled = true;

        /* If OTP Write protection is enabled (User 2), list each
         * sector that has it enabled */
        char otp_str[8];
        if (otp_enabled) {
                strcat(prot_str, "\nOTP Protection is enabled for sectors:\n");
                for (int i = 0; i < bank->num_sectors; i++) {
                        if (fb->write_prot_otp[i]) {
                                snprintf(otp_str, sizeof(otp_str), "- %d\n", i);
                                strncat(prot_str, otp_str, ARRAY_SIZE(otp_str));
                        }
                }
        }

        if (rev_str != NULL)
                snprintf(buf, buf_size, "%s - Rev: %s%s",
                         dev_str, rev_str, prot_str);
        else
                snprintf(buf, buf_size, "%s - Rev: unknown (0x%01x)%s",
                         dev_str, rev_id, prot_str);

        return ERROR_OK;
}

static int xmc4xxx_temp_unprotect(struct flash_bank *bank, int user_level)
{
        struct xmc4xxx_flash_bank *fb;
        int res = ERROR_OK;
        uint32_t status = 0;

        struct xmc4xxx_command_seq temp_unprot_seq[6] = {
                {FLASH_CMD_TEMP_UNPROT_1, 0xAA},
                {FLASH_CMD_TEMP_UNPROT_2, 0x55},
                {FLASH_CMD_TEMP_UNPROT_3, 0xFF}, /* Needs filled in */
                {FLASH_CMD_TEMP_UNPROT_4, 0xFF}, /* Needs filled in */
                {FLASH_CMD_TEMP_UNPROT_5, 0xFF}, /* Needs filled in */
                {FLASH_CMD_TEMP_UNPROT_6, 0x05}
        };

        if (user_level < 0 || user_level > 2) {
                LOG_ERROR("Invalid user level, must be 0-2");
                return ERROR_FAIL;
        }

        fb = bank->driver_priv;

        /* Fill in the user level and passwords */
        temp_unprot_seq[2].magic = user_level;
        temp_unprot_seq[3].magic = fb->pw1;
        temp_unprot_seq[4].magic = fb->pw2;

        res = xmc4xxx_write_command_sequence(bank, temp_unprot_seq,
                                             ARRAY_SIZE(temp_unprot_seq));
        if (res != ERROR_OK) {
                LOG_ERROR("Unable to write temp unprotect sequence");
                return res;
        }

        res = xmc4xxx_get_flash_status(bank, &status);
        if (res != ERROR_OK)
                return res;

        if (status & FSR_WPRODIS0) {
                LOG_INFO("Flash is temporarily unprotected");
        } else {
                LOG_INFO("Unable to disable flash protection");
                res = ERROR_FAIL;
        }


        return res;
}

static int xmc4xxx_flash_unprotect(struct flash_bank *bank, int32_t level)
{
        uint32_t addr;
        int res;

        if ((level < 0) || (level > 1)) {
                LOG_ERROR("Invalid user level. Must be 0-1");
                return ERROR_FAIL;
        }

        switch (level) {
        case 0:
                addr = UCB0_BASE;
                break;
        case 1:
                addr = UCB1_BASE;
                break;
        }

        res = xmc4xxx_erase_sector(bank, addr, true);

        if (res != ERROR_OK)
                LOG_ERROR("Error erasing user configuration block");

        return res;
}

/* Reference: "XMC4500 Flash Protection.pptx" app note */
static int xmc4xxx_flash_protect(struct flash_bank *bank, int level, bool read_protect,
                                 int first, int last)
{
        /* User configuration block buffers */
        uint8_t ucp0_buf[8 * sizeof(uint32_t)] = {0};
        uint32_t ucb_base = 0;
        uint32_t procon = 0;
        int res = ERROR_OK;
        uint32_t status = 0;
        bool proin = false;

        struct xmc4xxx_flash_bank *fb = bank->driver_priv;

        /* Read protect only works for user 0, make sure we don't try
         * to do something silly */
        if (level != 0 && read_protect) {
                LOG_ERROR("Read protection is for user level 0 only!");
                return ERROR_FAIL;
        }

        /* Check to see if protection is already installed for the
         * specified user level.  If it is, the user configuration
         * block will need to be erased before we can continue */

        /* Grab the flash status register*/
        res = xmc4xxx_get_flash_status(bank, &status);
        if (res != ERROR_OK)
                return res;

        switch (level) {
        case 0:
                if ((status & FSR_RPROIN_MASK) || (status & FSR_WPROIN0_MASK))
                        proin = true;
                break;
        case 1:
                if (status & FSR_WPROIN1_MASK)
                        proin = true;
                break;
        case 2:
                if (status & FSR_WPROIN2_MASK)
                        proin = true;
                break;
        }

        if (proin) {
                LOG_ERROR("Flash protection is installed for user %d"
                          " and must be removed before continuing", level);
                return ERROR_FAIL;
        }

        /* If this device has 12 flash sectors, protection for
         * sectors 10 & 11 are handled jointly. If we are trying to
         * write all sectors, we should decrement
         * last to ensure we don't write to a register bit that
         * doesn't exist*/
        if ((bank->num_sectors == 12) && (last == 12))
                last--;

        /*  We need to fill out the procon register representation
         *   that we will be writing to the device */
        for (int i = first; i <= last; i++)
                procon |= 1 << i;

        /* If read protection is requested, set the appropriate bit
         * (we checked that this is allowed above) */
        if (read_protect)
                procon |= PROCON_RPRO_MASK;

        LOG_DEBUG("Setting flash protection with procon:");
        LOG_DEBUG("PROCON: %"PRIx32, procon);

        /* First we need to copy in the procon register to the buffer
         * we're going to attempt to write.  This is written twice */
        target_buffer_set_u32(bank->target, &ucp0_buf[0 * 4], procon);
        target_buffer_set_u32(bank->target, &ucp0_buf[2 * 4], procon);

        /* Now we must copy in both flash passwords.  As with the
         * procon data, this must be written twice (4 total words
         * worth of data) */
        target_buffer_set_u32(bank->target, &ucp0_buf[4 * 4], fb->pw1);
        target_buffer_set_u32(bank->target, &ucp0_buf[5 * 4], fb->pw2);
        target_buffer_set_u32(bank->target, &ucp0_buf[6 * 4], fb->pw1);
        target_buffer_set_u32(bank->target, &ucp0_buf[7 * 4], fb->pw2);

        /* Finally, (if requested) we copy in the confirmation
         * code so that the protection is permanent and will
         * require a password to undo. */
        target_buffer_set_u32(bank->target, &ucp0_buf[0 * 4], FLASH_PROTECT_CONFIRMATION_CODE);
        target_buffer_set_u32(bank->target, &ucp0_buf[2 * 4], FLASH_PROTECT_CONFIRMATION_CODE);

        /* Now that the data is copied into place, we must write
         * these pages into flash */

        /* The user configuration block base depends on what level of
         * protection we're trying to install, select the proper one */
        switch (level) {
        case 0:
                ucb_base = UCB0_BASE;
                break;
        case 1:
                ucb_base = UCB1_BASE;
                break;
        case 2:
                ucb_base = UCB2_BASE;
                break;
        }

        /* Write the user config pages */
        res = xmc4xxx_write_page(bank, ucp0_buf, ucb_base, true);
        if (res != ERROR_OK) {
                LOG_ERROR("Error writing user configuration block 0");
                return res;
        }

        return ERROR_OK;
}

static int xmc4xxx_protect(struct flash_bank *bank, int set, int first, int last)
{
        int ret;
        struct xmc4xxx_flash_bank *fb = bank->driver_priv;

        /* Check for flash passwords */
        if (!fb->pw_set) {
                LOG_ERROR("Flash passwords not set, use xmc4xxx flash_password to set them");
                return ERROR_FAIL;
        }

        /* We want to clear flash protection temporarily*/
        if (set == 0) {
                LOG_WARNING("Flash protection will be temporarily disabled"
                            " for all pages (User 0 only)!");
                ret = xmc4xxx_temp_unprotect(bank, 0);
                return ret;
        }

        /* Install write protection for user 0 on the specified pages */
        ret = xmc4xxx_flash_protect(bank, 0, false, first, last);

        return ret;
}

static int xmc4xxx_protect_check(struct flash_bank *bank)
{
        int ret;
        uint32_t protection[3] = {0};
        struct xmc4xxx_flash_bank *fb = bank->driver_priv;

        ret = target_read_u32(bank->target, FLASH_REG_FLASH0_PROCON0, &protection[0]);
        if (ret != ERROR_OK) {
                LOG_ERROR("Unable to read flash User0 protection register");
                return ret;
        }

        ret = target_read_u32(bank->target, FLASH_REG_FLASH0_PROCON1, &protection[1]);
        if (ret != ERROR_OK) {
                LOG_ERROR("Unable to read flash User1 protection register");
                return ret;
        }

        ret = target_read_u32(bank->target, FLASH_REG_FLASH0_PROCON2, &protection[2]);
        if (ret != ERROR_OK) {
                LOG_ERROR("Unable to read flash User2 protection register");
                return ret;
        }

        int sectors = bank->num_sectors;

        /* On devices with 12 sectors, sectors 10 & 11 are ptected
         * together instead of individually */
        if (sectors == 12)
                sectors--;

        /* Clear the protection status */
        for (int i = 0; i < bank->num_sectors; i++) {
                bank->sectors[i].is_protected = 0;
                fb->write_prot_otp[i] = false;
        }
        fb->read_protected = false;

        /* The xmc4xxx series supports 3 levels of user protection
         * (User0, User1 (low priority), and User 2(OTP), we need to
         * check all 3 */
        for (unsigned int i = 0; i < ARRAY_SIZE(protection); i++) {

                /* Check for write protection on every available
                *  sector */
                for (int j = 0; j < sectors; j++) {
                        int set = (protection[i] & (1 << j)) ? 1 : 0;
                        bank->sectors[j].is_protected |= set;

                        /* Handle sector 11 */
                        if (j == 10)
                                bank->sectors[j + 1].is_protected |= set;

                        /* User 2 indicates this protection is
                         * permanent, make note in the private driver structure */
                        if (i == 2 && set) {
                                fb->write_prot_otp[j] = true;

                                /* Handle sector 11 */
                                if (j == 10)
                                        fb->write_prot_otp[j + 1] = true;
                        }

                }
        }

        /* XMC4xxx also supports read proptection, make a note
         * in the private driver structure */
        if (protection[0] & PROCON_RPRO_MASK)
                fb->read_protected = true;

        return ERROR_OK;
}

FLASH_BANK_COMMAND_HANDLER(xmc4xxx_flash_bank_command)
{
        bank->driver_priv = malloc(sizeof(struct xmc4xxx_flash_bank));

        if (!bank->driver_priv)
                return ERROR_FLASH_OPERATION_FAILED;

        (void)memset(bank->driver_priv, 0, sizeof(struct xmc4xxx_flash_bank));

        return ERROR_OK;
}

COMMAND_HANDLER(xmc4xxx_handle_flash_password_command)
{
        int res;
        struct flash_bank *bank;

        if (CMD_ARGC < 3)
                return ERROR_COMMAND_SYNTAX_ERROR;

        res = CALL_COMMAND_HANDLER(flash_command_get_bank, 0, &bank);
        if (res != ERROR_OK)
                return res;

        struct xmc4xxx_flash_bank *fb = bank->driver_priv;

        errno = 0;

        /* We skip over the flash bank */
        fb->pw1 = strtol(CMD_ARGV[1], NULL, 16);

        if (errno)
                return ERROR_COMMAND_SYNTAX_ERROR;

        fb->pw2 = strtol(CMD_ARGV[2], NULL, 16);

        if (errno)
                return ERROR_COMMAND_SYNTAX_ERROR;

        fb->pw_set = true;

        command_print(CMD_CTX, "XMC4xxx flash passwords set to:\n");
        command_print(CMD_CTX, "-0x%08"PRIx32"\n", fb->pw1);
        command_print(CMD_CTX, "-0x%08"PRIx32"\n", fb->pw2);
        return ERROR_OK;
}

COMMAND_HANDLER(xmc4xxx_handle_flash_unprotect_command)
{
        struct flash_bank *bank;
        int res;
        int32_t level;

        if (CMD_ARGC < 2)
                return ERROR_COMMAND_SYNTAX_ERROR;

        res = CALL_COMMAND_HANDLER(flash_command_get_bank, 0, &bank);
        if (res != ERROR_OK)
                return res;

        COMMAND_PARSE_NUMBER(s32, CMD_ARGV[1], level);

        res = xmc4xxx_flash_unprotect(bank, level);

        return res;
}

static const struct command_registration xmc4xxx_exec_command_handlers[] = {
        {
                .name = "flash_password",
                .handler = xmc4xxx_handle_flash_password_command,
                .mode = COMMAND_EXEC,
                .usage = "bank_id password1 password2",
                .help = "Set the flash passwords used for protect operations. "
                "Passwords should be in standard hex form (0x00000000). "
                "(You must call this before any other protect commands) "
                "NOTE: The xmc4xxx's UCB area only allows for FOUR cycles. "
                "Please use protection carefully!",
        },
        {
                .name = "flash_unprotect",
                .handler = xmc4xxx_handle_flash_unprotect_command,
                .mode = COMMAND_EXEC,
                .usage = "bank_id user_level[0-1]",
                .help = "Permanently Removes flash protection (read and write) "
                "for the specified user level",
        },      COMMAND_REGISTRATION_DONE
};

static const struct command_registration xmc4xxx_command_handlers[] = {
        {
                .name = "xmc4xxx",
                .mode = COMMAND_ANY,
                .help = "xmc4xxx flash command group",
                .usage = "",
                .chain = xmc4xxx_exec_command_handlers,
        },
        COMMAND_REGISTRATION_DONE
};

struct flash_driver xmc4xxx_flash = {
        .name = "xmc4xxx",
        .commands = xmc4xxx_command_handlers,
        .flash_bank_command = xmc4xxx_flash_bank_command,
        .erase = xmc4xxx_erase,
        .write = xmc4xxx_write,
        .read = default_flash_read,
        .probe = xmc4xxx_probe,
        .auto_probe = xmc4xxx_probe,
        .erase_check = xmc4xxx_flash_blank_check,
        .info = xmc4xxx_get_info_command,
        .protect_check = xmc4xxx_protect_check,
        .protect = xmc4xxx_protect,
};