[fw/openocd] / src / flash / lpc2900.c

/***************************************************************************
 *   Copyright (C) 2009 by                                                 *
 *   Rolf Meeser <rolfm_9dq@yahoo.de>                                      *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/

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


#include "image.h"

#include "lpc2900.h"
#include "binarybuffer.h"
#include "armv4_5.h"


/* 1024 bytes */
#define KiB                 1024

/* Some flash constants */
#define FLASH_PAGE_SIZE     512     /* bytes */
#define FLASH_ERASE_TIME    100000  /* microseconds */
#define FLASH_PROGRAM_TIME  1000    /* microseconds */

/* Chip ID / Feature Registers */
#define CHIPID          0xE0000000  /* Chip ID */
#define FEAT0           0xE0000100  /* Chip feature 0 */
#define FEAT1           0xE0000104  /* Chip feature 1 */
#define FEAT2           0xE0000108  /* Chip feature 2 (contains flash size indicator) */
#define FEAT3           0xE000010C  /* Chip feature 3 */

#define EXPECTED_CHIPID 0x209CE02B  /* Chip ID of all LPC2900 devices */

/* Flash/EEPROM Control Registers */
#define FCTR            0x20200000  /* Flash control */
#define FPTR            0x20200008  /* Flash program-time */
#define FTCTR           0x2020000C  /* Flash test control */
#define FBWST           0x20200010  /* Flash bridge wait-state */
#define FCRA            0x2020001C  /* Flash clock divider */
#define FMSSTART        0x20200020  /* Flash Built-In Selft Test start address */
#define FMSSTOP         0x20200024  /* Flash Built-In Selft Test stop address */
#define FMS16           0x20200028  /* Flash 16-bit signature */
#define FMSW0           0x2020002C  /* Flash 128-bit signature Word 0 */
#define FMSW1           0x20200030  /* Flash 128-bit signature Word 1 */
#define FMSW2           0x20200034  /* Flash 128-bit signature Word 2 */
#define FMSW3           0x20200038  /* Flash 128-bit signature Word 3 */

#define EECMD           0x20200080  /* EEPROM command */
#define EEADDR          0x20200084  /* EEPROM address */
#define EEWDATA         0x20200088  /* EEPROM write data */
#define EERDATA         0x2020008C  /* EEPROM read data */
#define EEWSTATE        0x20200090  /* EEPROM wait state */
#define EECLKDIV        0x20200094  /* EEPROM clock divider */
#define EEPWRDWN        0x20200098  /* EEPROM power-down/start */
#define EEMSSTART       0x2020009C  /* EEPROM BIST start address */
#define EEMSSTOP        0x202000A0  /* EEPROM BIST stop address */
#define EEMSSIG         0x202000A4  /* EEPROM 24-bit BIST signature */

#define INT_CLR_ENABLE  0x20200FD8  /* Flash/EEPROM interrupt clear enable */
#define INT_SET_ENABLE  0x20200FDC  /* Flash/EEPROM interrupt set enable */
#define INT_STATUS      0x20200FE0  /* Flash/EEPROM interrupt status */
#define INT_ENABLE      0x20200FE4  /* Flash/EEPROM interrupt enable */
#define INT_CLR_STATUS  0x20200FE8  /* Flash/EEPROM interrupt clear status */
#define INT_SET_STATUS  0x20200FEC  /* Flash/EEPROM interrupt set status */

/* Interrupt sources */
#define INTSRC_END_OF_PROG    (1 << 28)
#define INTSRC_END_OF_BIST    (1 << 27)
#define INTSRC_END_OF_RDWR    (1 << 26)
#define INTSRC_END_OF_MISR    (1 << 2)
#define INTSRC_END_OF_BURN    (1 << 1)
#define INTSRC_END_OF_ERASE   (1 << 0)


/* FCTR bits */
#define FCTR_FS_LOADREQ       (1 << 15)
#define FCTR_FS_CACHECLR      (1 << 14)
#define FCTR_FS_CACHEBYP      (1 << 13)
#define FCTR_FS_PROGREQ       (1 << 12)
#define FCTR_FS_RLS           (1 << 11)
#define FCTR_FS_PDL           (1 << 10)
#define FCTR_FS_PD            (1 << 9)
#define FCTR_FS_WPB           (1 << 7)
#define FCTR_FS_ISS           (1 << 6)
#define FCTR_FS_RLD           (1 << 5)
#define FCTR_FS_DCR           (1 << 4)
#define FCTR_FS_WEB           (1 << 2)
#define FCTR_FS_WRE           (1 << 1)
#define FCTR_FS_CS            (1 << 0)
/* FPTR bits */
#define FPTR_EN_T             (1 << 15)
/* FTCTR bits */
#define FTCTR_FS_BYPASS_R     (1 << 29)
#define FTCTR_FS_BYPASS_W     (1 << 28)
/* FMSSTOP bits */
#define FMSSTOP_MISR_START    (1 << 17)
/* EEMSSTOP bits */
#define EEMSSTOP_STRTBIST     (1 << 31)

/* Index sector */
#define ISS_CUSTOMER_START1   (0x830)
#define ISS_CUSTOMER_END1     (0xA00)
#define ISS_CUSTOMER_SIZE1    (ISS_CUSTOMER_END1 - ISS_CUSTOMER_START1)
#define ISS_CUSTOMER_NWORDS1  (ISS_CUSTOMER_SIZE1 / 4)
#define ISS_CUSTOMER_START2   (0xA40)
#define ISS_CUSTOMER_END2     (0xC00)
#define ISS_CUSTOMER_SIZE2    (ISS_CUSTOMER_END2 - ISS_CUSTOMER_START2)
#define ISS_CUSTOMER_NWORDS2  (ISS_CUSTOMER_SIZE2 / 4)
#define ISS_CUSTOMER_SIZE     (ISS_CUSTOMER_SIZE1 + ISS_CUSTOMER_SIZE2)



/**
 * Private data for \c lpc2900 flash driver.
 */
typedef struct lpc2900_flash_bank_s
{
        /**
         * Holds the value read from CHIPID register.
         * The driver will not load if the chipid doesn't match the expected
         * value of 0x209CE02B of the LPC2900 family. A probe will only be done
         * if the chipid does not yet contain the expected value.
         */
        uint32_t chipid;

        /**
         * String holding device name.
         * This string is set by the probe function to the type number of the
         * device. It takes the form "LPC29xx".
         */
        char * target_name;

        /**
         * System clock frequency.
         * Holds the clock frequency in Hz, as passed by the configuration file
         * to the <tt>flash bank</tt> command.
         */
        uint32_t clk_sys_fmc;

        /**
         * Flag to indicate that dangerous operations are possible.
         * This flag can be set by passing the correct password to the
         * <tt>lpc2900 password</tt> command. If set, other dangerous commands,
         * which operate on the index sector, can be executed.
         */
        uint32_t risky;

        /**
         * Maximum contiguous block of internal SRAM (bytes).
         * Autodetected by the driver. Not the total amount of SRAM, only the
         * the largest \em contiguous block!
         */
        uint32_t max_ram_block;

} lpc2900_flash_bank_t;


static uint32_t lpc2900_wait_status(flash_bank_t *bank, uint32_t mask, int timeout);
static void lpc2900_setup(struct flash_bank_s *bank);
static uint32_t lpc2900_is_ready(struct flash_bank_s *bank);
static uint32_t lpc2900_read_security_status(struct flash_bank_s *bank);
static uint32_t lpc2900_run_bist128(struct flash_bank_s *bank,
                                    uint32_t addr_from, uint32_t addr_to,
                                    uint32_t (*signature)[4] );
static uint32_t lpc2900_address2sector(struct flash_bank_s *bank, uint32_t offset);
static uint32_t lpc2900_calc_tr( uint32_t clock, uint32_t time );


/***********************  Helper functions  **************************/


/**
 * Wait for an event in mask to occur in INT_STATUS.
 *
 * Return when an event occurs, or after a timeout.
 *
 * @param[in] bank Pointer to the flash bank descriptor
 * @param[in] mask Mask to be used for INT_STATUS
 * @param[in] timeout Timeout in ms
 */
static uint32_t lpc2900_wait_status( flash_bank_t *bank,
                                     uint32_t mask,
                                     int timeout )
{
        uint32_t int_status;
        target_t *target = bank->target;


        do
        {
                alive_sleep(1);
                timeout--;
                target_read_u32(target, INT_STATUS, &int_status);
        }
        while( ((int_status & mask) == 0) && (timeout != 0) );

        if (timeout == 0)
        {
                LOG_DEBUG("Timeout!");
                return ERROR_FLASH_OPERATION_FAILED;
        }

        return ERROR_OK;
}



/**
 * Set up the flash for erase/program operations.
 *
 * Enable the flash, and set the correct CRA clock of 66 kHz.
 *
 * @param bank Pointer to the flash bank descriptor
 */
static void lpc2900_setup( struct flash_bank_s *bank )
{
        uint32_t fcra;
        lpc2900_flash_bank_t *lpc2900_info = bank->driver_priv;


        /* Power up the flash block */
        target_write_u32( bank->target, FCTR, FCTR_FS_WEB | FCTR_FS_CS );


        fcra = (lpc2900_info->clk_sys_fmc / (3 * 66000)) - 1;
        target_write_u32( bank->target, FCRA, fcra );
}



/**
 * Check if device is ready.
 *
 * Check if device is ready for flash operation:
 * Must have been successfully probed.
 * Must be halted.
 */
static uint32_t lpc2900_is_ready( struct flash_bank_s *bank )
{
        lpc2900_flash_bank_t *lpc2900_info = bank->driver_priv;

        if( lpc2900_info->chipid != EXPECTED_CHIPID )
        {
                return ERROR_FLASH_BANK_NOT_PROBED;
        }

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

        return ERROR_OK;
}


/**
 * Read the status of sector security from the index sector.
 *
 * @param bank Pointer to the flash bank descriptor
 */
static uint32_t lpc2900_read_security_status( struct flash_bank_s *bank )
{
        uint32_t status;
        if( (status = lpc2900_is_ready( bank )) != ERROR_OK )
        {
                return status;
        }

        target_t *target = bank->target;

        /* Enable ISS access */
        target_write_u32(target, FCTR, FCTR_FS_CS | FCTR_FS_WEB | FCTR_FS_ISS);

        /* Read the relevant block of memory from the ISS sector */
        uint32_t iss_secured_field[ 0x230/16 ][ 4 ];
        target_read_memory(target, bank->base + 0xC00, 4, 0x230/4,
                                   (uint8_t *)iss_secured_field);

        /* Disable ISS access */
        target_write_u32(target, FCTR, FCTR_FS_CS | FCTR_FS_WEB);

        /* Check status of each sector. Note that the sector numbering in the LPC2900
         * is different from the logical sector numbers used in OpenOCD!
         * Refer to the user manual for details.
         *
         * All zeros (16x 0x00) are treated as a secured sector (is_protected = 1)
         * All ones (16x 0xFF) are treated as a non-secured sector (is_protected = 0)
         * Anything else is undefined (is_protected = -1). This is treated as
         * a protected sector!
         */
        int sector;
        int index;
        for( sector = 0; sector < bank->num_sectors; sector++ )
        {
                /* Convert logical sector number to physical sector number */
                if( sector <= 4 )
                {
                        index = sector + 11;
                }
                else if( sector <= 7 )
                {
                        index = sector + 27;
                }
                else
                {
                        index = sector - 8;
                }

                bank->sectors[sector].is_protected = -1;

                if (
                    (iss_secured_field[index][0] == 0x00000000) &&
                    (iss_secured_field[index][1] == 0x00000000) &&
                    (iss_secured_field[index][2] == 0x00000000) &&
                    (iss_secured_field[index][3] == 0x00000000) )
                {
                        bank->sectors[sector].is_protected = 1;
                }

                if (
                    (iss_secured_field[index][0] == 0xFFFFFFFF) &&
                    (iss_secured_field[index][1] == 0xFFFFFFFF) &&
                    (iss_secured_field[index][2] == 0xFFFFFFFF) &&
                    (iss_secured_field[index][3] == 0xFFFFFFFF) )
                {
                        bank->sectors[sector].is_protected = 0;
                }
        }

        return ERROR_OK;
}


/**
 * Use BIST to calculate a 128-bit hash value over a range of flash.
 *
 * @param bank Pointer to the flash bank descriptor
 * @param addr_from
 * @param addr_to
 * @param signature
 */
static uint32_t lpc2900_run_bist128(struct flash_bank_s *bank,
                                    uint32_t addr_from,
                                    uint32_t addr_to,
                                    uint32_t (*signature)[4] )
{
        target_t *target = bank->target;

        /* Clear END_OF_MISR interrupt status */
        target_write_u32( target, INT_CLR_STATUS, INTSRC_END_OF_MISR );

        /* Start address */
        target_write_u32( target, FMSSTART, addr_from >> 4);
        /* End address, and issue start command */
        target_write_u32( target, FMSSTOP, (addr_to >> 4) | FMSSTOP_MISR_START );

        /* Poll for end of operation. Calculate a reasonable timeout. */
        if( lpc2900_wait_status( bank, INTSRC_END_OF_MISR, 1000 ) != ERROR_OK )
        {
                return ERROR_FLASH_OPERATION_FAILED;
        }

        /* Return the signature */
        target_read_memory( target, FMSW0, 4, 4, (uint8_t *)signature );

        return ERROR_OK;
}


/**
 * Return sector number for given address.
 *
 * Return the (logical) sector number for a given relative address.
 * No sanity check is done. It assumed that the address is valid.
 *
 * @param bank Pointer to the flash bank descriptor
 * @param offset Offset address relative to bank start
 */
static uint32_t lpc2900_address2sector( struct flash_bank_s *bank,
                                        uint32_t offset )
{
        uint32_t address = bank->base + offset;


        /* Run through all sectors of this bank */
        int sector;
        for( sector = 0; sector < bank->num_sectors; sector++ )
        {
                /* Return immediately if address is within the current sector */
                if( address < (bank->sectors[sector].offset + bank->sectors[sector].size) )
                {
                        return sector;
                }
        }

        /* We should never come here. If we do, return an arbitrary sector number. */
        return 0;
}




/**
 * Write one page to the index sector.
 *
 * @param bank Pointer to the flash bank descriptor
 * @param pagenum Page number (0...7)
 * @param page Page array (FLASH_PAGE_SIZE bytes)
 */
static int lpc2900_write_index_page( struct flash_bank_s *bank,
                                     int pagenum,
                                     uint8_t (*page)[FLASH_PAGE_SIZE] )
{
        /* Only pages 4...7 are user writable */
        if ((pagenum < 4) || (pagenum > 7))
        {
                LOG_ERROR("Refuse to burn index sector page %d", pagenum);
                return ERROR_COMMAND_ARGUMENT_INVALID;
        }

        /* Get target, and check if it's halted */
        target_t *target = bank->target;
        if( target->state != TARGET_HALTED )
        {
                LOG_ERROR( "Target not halted" );
                return ERROR_TARGET_NOT_HALTED;
        }

        /* Private info */
        lpc2900_flash_bank_t *lpc2900_info = bank->driver_priv;

        /* Enable flash block and set the correct CRA clock of 66 kHz */
        lpc2900_setup( bank );

        /* Un-protect the index sector */
        target_write_u32( target, bank->base, 0 );
        target_write_u32( target, FCTR,
                          FCTR_FS_LOADREQ | FCTR_FS_WPB | FCTR_FS_ISS |
                          FCTR_FS_WEB | FCTR_FS_WRE | FCTR_FS_CS );

        /* Set latch load mode */
        target_write_u32( target, FCTR,
                          FCTR_FS_ISS | FCTR_FS_WEB | FCTR_FS_WRE | FCTR_FS_CS );

        /* Write whole page to flash data latches */
        if( target_write_memory( target,
                                 bank->base + pagenum * FLASH_PAGE_SIZE,
                                 4, FLASH_PAGE_SIZE / 4, (uint8_t *)page) != ERROR_OK )
        {
                LOG_ERROR("Index sector write failed @ page %d", pagenum);
                target_write_u32( target, FCTR, FCTR_FS_CS | FCTR_FS_WEB );

                return ERROR_FLASH_OPERATION_FAILED;
        }

        /* Clear END_OF_BURN interrupt status */
        target_write_u32( target, INT_CLR_STATUS, INTSRC_END_OF_BURN );

        /* Set the program/erase time to FLASH_PROGRAM_TIME */
        target_write_u32(target, FPTR,
                         FPTR_EN_T | lpc2900_calc_tr( lpc2900_info->clk_sys_fmc,
                                                      FLASH_PROGRAM_TIME ));

        /* Trigger flash write */
        target_write_u32( target, FCTR,
                          FCTR_FS_PROGREQ | FCTR_FS_ISS |
                          FCTR_FS_WPB | FCTR_FS_WRE | FCTR_FS_CS );

        /* Wait for the end of the write operation. If it's not over after one
         * second, something went dreadfully wrong... :-(
         */
        if (lpc2900_wait_status(bank, INTSRC_END_OF_BURN, 1000) != ERROR_OK)
        {
                LOG_ERROR("Index sector write failed @ page %d", pagenum);
                target_write_u32(target, FCTR, FCTR_FS_CS | FCTR_FS_WEB);

                return ERROR_FLASH_OPERATION_FAILED;
        }

        target_write_u32( target, FCTR, FCTR_FS_CS | FCTR_FS_WEB );

        return ERROR_OK;
}



/**
 * Calculate FPTR.TR register value for desired program/erase time.
 *
 * @param clock System clock in Hz
 * @param time Program/erase time in µs
 */
static uint32_t lpc2900_calc_tr( uint32_t clock, uint32_t time )
{
        /*           ((time[µs]/1e6) * f[Hz]) + 511
         * FPTR.TR = -------------------------------
         *                         512
         *
         * The result is the
         */

        uint32_t tr_val = (uint32_t)((((time / 1e6) * clock) + 511.0) / 512.0);

        return tr_val;
}


/***********************  Private flash commands  **************************/


/**
 * Command to determine the signature of the whole flash.
 *
 * Uses the Built-In-Self-Test (BIST) to generate a 128-bit hash value
 * of the flash content.
 */
static int lpc2900_handle_signature_command( struct command_context_s *cmd_ctx,
                                             char *cmd, char **args, int argc )
{
        uint32_t status;
        uint32_t signature[4];


        if( argc < 1 )
        {
                LOG_WARNING( "Too few arguments. Call: lpc2900 signature <bank#>" );
                return ERROR_FLASH_BANK_INVALID;
        }

        flash_bank_t *bank;
        int retval = flash_command_get_bank_by_num(cmd_ctx, args[0], &bank);
        if (ERROR_OK != retval)
                return retval;

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

        /* Run BIST over whole flash range */
        if( (status = lpc2900_run_bist128( bank,
                                           bank->base,
                                           bank->base + (bank->size - 1),
                                           &signature)
                                         ) != ERROR_OK )
        {
                return status;
        }

        command_print( cmd_ctx, "signature: 0x%8.8" PRIx32
                                          ":0x%8.8" PRIx32
                                          ":0x%8.8" PRIx32
                                          ":0x%8.8" PRIx32,
                      signature[3], signature[2], signature[1], signature[0] );

        return ERROR_OK;
}



/**
 * Store customer info in file.
 *
 * Read customer info from index sector, and store that block of data into
 * a disk file. The format is binary.
 */
static int lpc2900_handle_read_custom_command( struct command_context_s *cmd_ctx,
                                               char *cmd, char **args, int argc )
{
        if( argc < 2 )
        {
                return ERROR_COMMAND_SYNTAX_ERROR;
        }

        flash_bank_t *bank;
        int retval = flash_command_get_bank_by_num(cmd_ctx, args[0], &bank);
        if (ERROR_OK != retval)
                return retval;

        lpc2900_flash_bank_t *lpc2900_info = bank->driver_priv;
        lpc2900_info->risky = 0;

        /* Get target, and check if it's halted */
        target_t *target = bank->target;
        if( target->state != TARGET_HALTED )
        {
                LOG_ERROR( "Target not halted" );
                return ERROR_TARGET_NOT_HALTED;
        }

        /* Storage for customer info. Read in two parts */
        uint32_t customer[ ISS_CUSTOMER_NWORDS1 + ISS_CUSTOMER_NWORDS2 ];

        /* Enable access to index sector */
        target_write_u32( target, FCTR, FCTR_FS_CS | FCTR_FS_WEB | FCTR_FS_ISS );

        /* Read two parts */
        target_read_memory( target, bank->base+ISS_CUSTOMER_START1, 4,
                                    ISS_CUSTOMER_NWORDS1,
                                    (uint8_t *)&customer[0] );
        target_read_memory( target, bank->base+ISS_CUSTOMER_START2, 4,
                                    ISS_CUSTOMER_NWORDS2,
                                    (uint8_t *)&customer[ISS_CUSTOMER_NWORDS1] );

        /* Deactivate access to index sector */
        target_write_u32( target, FCTR, FCTR_FS_CS | FCTR_FS_WEB );

        /* Try and open the file */
        fileio_t fileio;
        const char *filename = args[1];
        int ret = fileio_open( &fileio, filename, FILEIO_WRITE, FILEIO_BINARY );
        if( ret != ERROR_OK )
        {
                LOG_WARNING( "Could not open file %s", filename );
                return ret;
        }

        uint32_t nwritten;
        ret = fileio_write( &fileio, sizeof(customer),
                        (const uint8_t *)customer, &nwritten );
        if( ret != ERROR_OK )
        {
                LOG_ERROR( "Write operation to file %s failed", filename );
                fileio_close( &fileio );
                return ret;
        }

        fileio_close( &fileio );

        return ERROR_OK;
}




/**
 * Enter password to enable potentially dangerous options.
 */
static int lpc2900_handle_password_command(struct command_context_s *cmd_ctx,
                                           char *cmd, char **args, int argc)
{
        if (argc < 2)
        {
                return ERROR_COMMAND_SYNTAX_ERROR;
        }

        flash_bank_t *bank;
        int retval = flash_command_get_bank_by_num(cmd_ctx, args[0], &bank);
        if (ERROR_OK != retval)
                return retval;

        lpc2900_flash_bank_t *lpc2900_info = bank->driver_priv;

#define ISS_PASSWORD "I_know_what_I_am_doing"

        lpc2900_info->risky = !strcmp( args[1], ISS_PASSWORD );

        if( !lpc2900_info->risky )
        {
                command_print(cmd_ctx, "Wrong password (use '%s')", ISS_PASSWORD);
                return ERROR_COMMAND_ARGUMENT_INVALID;
        }

        command_print(cmd_ctx,
                  "Potentially dangerous operation allowed in next command!");

        return ERROR_OK;
}



/**
 * Write customer info from file to the index sector.
 */
static int lpc2900_handle_write_custom_command( struct command_context_s *cmd_ctx,
                                                char *cmd, char **args, int argc )
{
        if (argc < 2)
        {
                return ERROR_COMMAND_SYNTAX_ERROR;
        }

        flash_bank_t *bank;
        int retval = flash_command_get_bank_by_num(cmd_ctx, args[0], &bank);
        if (ERROR_OK != retval)
                return retval;

        lpc2900_flash_bank_t *lpc2900_info = bank->driver_priv;

        /* Check if command execution is allowed. */
        if( !lpc2900_info->risky )
        {
                command_print( cmd_ctx, "Command execution not allowed!" );
                return ERROR_COMMAND_ARGUMENT_INVALID;
        }
        lpc2900_info->risky = 0;

        /* Get target, and check if it's halted */
        target_t *target = bank->target;
        if (target->state != TARGET_HALTED)
        {
                LOG_ERROR("Target not halted");
                return ERROR_TARGET_NOT_HALTED;
        }

        /* The image will always start at offset 0 */
        image_t image;
        image.base_address_set = 1;
        image.base_address = 0;
        image.start_address_set = 0;

        const char *filename = args[1];
        const char *type = (argc >= 3) ? args[2] : NULL;
        retval = image_open(&image, filename, type);
        if (retval != ERROR_OK)
        {
                return retval;
        }

        /* Do a sanity check: The image must be exactly the size of the customer
           programmable area. Any other size is rejected. */
        if( image.num_sections != 1 )
        {
                LOG_ERROR("Only one section allowed in image file.");
                return ERROR_COMMAND_SYNTAX_ERROR;
        }
        if( (image.sections[0].base_address != 0) ||
        (image.sections[0].size != ISS_CUSTOMER_SIZE) )
        {
                LOG_ERROR("Incorrect image file size. Expected %d, "
                        "got %" PRIu32,
                   ISS_CUSTOMER_SIZE, image.sections[0].size);
                return ERROR_COMMAND_SYNTAX_ERROR;
        }

        /* Well boys, I reckon this is it... */

        /* Customer info is split into two blocks in pages 4 and 5. */
        uint8_t page[FLASH_PAGE_SIZE];

        /* Page 4 */
        uint32_t offset = ISS_CUSTOMER_START1 % FLASH_PAGE_SIZE;
        memset( page, 0xff, FLASH_PAGE_SIZE );
        uint32_t size_read;
        retval = image_read_section( &image, 0, 0,
                                     ISS_CUSTOMER_SIZE1, &page[offset], &size_read);
        if( retval != ERROR_OK )
        {
                LOG_ERROR("couldn't read from file '%s'", filename);
                image_close(&image);
                return retval;
        }
        if( (retval = lpc2900_write_index_page( bank, 4, &page )) != ERROR_OK )
        {
                image_close(&image);
                return retval;
        }

        /* Page 5 */
        offset = ISS_CUSTOMER_START2 % FLASH_PAGE_SIZE;
        memset( page, 0xff, FLASH_PAGE_SIZE );
        retval = image_read_section( &image, 0, ISS_CUSTOMER_SIZE1,
                                     ISS_CUSTOMER_SIZE2, &page[offset], &size_read);
        if( retval != ERROR_OK )
        {
                LOG_ERROR("couldn't read from file '%s'", filename);
                image_close(&image);
                return retval;
        }
        if( (retval = lpc2900_write_index_page( bank, 5, &page )) != ERROR_OK )
        {
                image_close(&image);
                return retval;
        }

        image_close(&image);

        return ERROR_OK;
}



/**
 * Activate 'sector security' for a range of sectors.
 */
static int lpc2900_handle_secure_sector_command(struct command_context_s *cmd_ctx,
                                                char *cmd, char **args, int argc)
{
        if (argc < 3)
        {
                return ERROR_COMMAND_SYNTAX_ERROR;
        }

        /* Get the bank descriptor */
        flash_bank_t *bank;
        int retval = flash_command_get_bank_by_num(cmd_ctx, args[0], &bank);
        if (ERROR_OK != retval)
                return retval;

        lpc2900_flash_bank_t *lpc2900_info = bank->driver_priv;

        /* Check if command execution is allowed. */
        if( !lpc2900_info->risky )
        {
                command_print( cmd_ctx, "Command execution not allowed! "
                "(use 'password' command first)");
                return ERROR_COMMAND_ARGUMENT_INVALID;
        }
        lpc2900_info->risky = 0;

        /* Read sector range, and do a sanity check. */
        int first, last;
        COMMAND_PARSE_NUMBER(int, args[1], first);
        COMMAND_PARSE_NUMBER(int, args[2], last);
        if( (first >= bank->num_sectors) ||
            (last >= bank->num_sectors) ||
            (first > last) )
        {
                command_print( cmd_ctx, "Illegal sector range" );
                return ERROR_COMMAND_ARGUMENT_INVALID;
        }

        uint8_t page[FLASH_PAGE_SIZE];
        int sector;

        /* Sectors in page 6 */
        if( (first <= 4) || (last >= 8) )
        {
                memset( &page, 0xff, FLASH_PAGE_SIZE );
                for( sector = first; sector <= last; sector++ )
                {
                        if( sector <= 4 )
                        {
                                memset( &page[0xB0 + 16*sector], 0, 16 );
                        }
                        else if( sector >= 8 )
                        {
                                memset( &page[0x00 + 16*(sector - 8)], 0, 16 );
                        }
                }

                if( (retval = lpc2900_write_index_page( bank, 6, &page )) != ERROR_OK )
                {
                        LOG_ERROR("failed to update index sector page 6");
                        return retval;
                }
        }

        /* Sectors in page 7 */
        if( (first <= 7) && (last >= 5) )
        {
                memset( &page, 0xff, FLASH_PAGE_SIZE );
                for( sector = first; sector <= last; sector++ )
                {
                        if( (sector >= 5) && (sector <= 7) )
                        {
                                memset( &page[0x00 + 16*(sector - 5)], 0, 16 );
                        }
                }

                if( (retval = lpc2900_write_index_page( bank, 7, &page )) != ERROR_OK )
                {
                        LOG_ERROR("failed to update index sector page 7");
                        return retval;
                }
        }

        command_print( cmd_ctx,
                "Sectors security will become effective after next power cycle");

        /* Update the sector security status */
        if ( lpc2900_read_security_status(bank) != ERROR_OK )
        {
                LOG_ERROR( "Cannot determine sector security status" );
                return ERROR_FLASH_OPERATION_FAILED;
        }

        return ERROR_OK;
}



/**
 * Activate JTAG protection.
 */
static int lpc2900_handle_secure_jtag_command(struct command_context_s *cmd_ctx,
                                              char *cmd, char **args, int argc)
{
        if (argc < 1)
        {
                return ERROR_COMMAND_SYNTAX_ERROR;
        }

        /* Get the bank descriptor */
        flash_bank_t *bank;
        int retval = flash_command_get_bank_by_num(cmd_ctx, args[0], &bank);
        if (ERROR_OK != retval)
                return retval;

        lpc2900_flash_bank_t *lpc2900_info = bank->driver_priv;

        /* Check if command execution is allowed. */
        if( !lpc2900_info->risky )
        {
                command_print( cmd_ctx, "Command execution not allowed! "
                                        "(use 'password' command first)");
                return ERROR_COMMAND_ARGUMENT_INVALID;
        }
        lpc2900_info->risky = 0;

        /* Prepare page */
        uint8_t page[FLASH_PAGE_SIZE];
        memset( &page, 0xff, FLASH_PAGE_SIZE );


        /* Insert "soft" protection word */
        page[0x30 + 15] = 0x7F;
        page[0x30 + 11] = 0x7F;
        page[0x30 +  7] = 0x7F;
        page[0x30 +  3] = 0x7F;

        /* Write to page 5 */
        if( (retval = lpc2900_write_index_page( bank, 5, &page ))
                        != ERROR_OK )
        {
                LOG_ERROR("failed to update index sector page 5");
                return retval;
        }

        LOG_INFO("JTAG security set. Good bye!");

        return ERROR_OK;
}



/***********************  Flash interface functions  **************************/


/**
 * Register private command handlers.
 */
static int lpc2900_register_commands(struct command_context_s *cmd_ctx)
{
        command_t *lpc2900_cmd = register_command(cmd_ctx, NULL, "lpc2900",
                                                  NULL, COMMAND_ANY, NULL);

        register_command(
            cmd_ctx,
            lpc2900_cmd,
            "signature",
            lpc2900_handle_signature_command,
            COMMAND_EXEC,
            "<bank> | "
            "print device signature of flash bank");

        register_command(
            cmd_ctx,
            lpc2900_cmd,
            "read_custom",
            lpc2900_handle_read_custom_command,
            COMMAND_EXEC,
            "<bank> <filename> | "
            "read customer information from index sector to file");

        register_command(
            cmd_ctx,
            lpc2900_cmd,
            "password",
            lpc2900_handle_password_command,
            COMMAND_EXEC,
            "<bank> <password> | "
            "enter password to enable 'dangerous' options");

        register_command(
            cmd_ctx,
            lpc2900_cmd,
            "write_custom",
            lpc2900_handle_write_custom_command,
            COMMAND_EXEC,
            "<bank> <filename> [<type>] | "
            "write customer info from file to index sector");

        register_command(
            cmd_ctx,
            lpc2900_cmd,
            "secure_sector",
            lpc2900_handle_secure_sector_command,
            COMMAND_EXEC,
            "<bank> <first> <last> | "
            "activate sector security for a range of sectors");

        register_command(
            cmd_ctx,
            lpc2900_cmd,
            "secure_jtag",
            lpc2900_handle_secure_jtag_command,
            COMMAND_EXEC,
            "<bank> <level> | "
            "activate JTAG security");

        return ERROR_OK;
}


/// Evaluate flash bank command.
static int lpc2900_flash_bank_command(struct command_context_s *cmd_ctx,
                                      char *cmd, char **args, int argc,
                                      struct flash_bank_s *bank)
{
        lpc2900_flash_bank_t *lpc2900_info;

        if (argc < 6)
        {
                LOG_WARNING("incomplete flash_bank LPC2900 configuration");
                return ERROR_FLASH_BANK_INVALID;
        }

        lpc2900_info = malloc(sizeof(lpc2900_flash_bank_t));
        bank->driver_priv = lpc2900_info;

        /* Get flash clock.
         * Reject it if we can't meet the requirements for program time
         * (if clock too slow), or for erase time (clock too fast).
         */
        uint32_t clk_sys_fmc;
        COMMAND_PARSE_NUMBER(u32, args[6], clk_sys_fmc);
        lpc2900_info->clk_sys_fmc = clk_sys_fmc * 1000;

        uint32_t clock_limit;
        /* Check program time limit */
        clock_limit = 512000000l / FLASH_PROGRAM_TIME;
        if (lpc2900_info->clk_sys_fmc < clock_limit)
        {
                LOG_WARNING("flash clock must be at least %" PRIu32 " kHz",
                    (clock_limit / 1000));
                return ERROR_FLASH_BANK_INVALID;
        }

        /* Check erase time limit */
        clock_limit = (uint32_t)((32767.0 * 512.0 * 1e6) / FLASH_ERASE_TIME);
        if (lpc2900_info->clk_sys_fmc > clock_limit)
        {
                LOG_WARNING("flash clock must be a maximum of %" PRIu32" kHz",
                    (clock_limit / 1000));
                return ERROR_FLASH_BANK_INVALID;
        }

        /* Chip ID will be obtained by probing the device later */
        lpc2900_info->chipid = 0;

        return ERROR_OK;
}


/**
 * Erase sector(s).
 *
 * @param bank Pointer to the flash bank descriptor
 * @param first First sector to be erased
 * @param last Last sector (including) to be erased
 */
static int lpc2900_erase(struct flash_bank_s *bank, int first, int last)
{
        uint32_t status;
        int sector;
        int last_unsecured_sector;
        target_t *target = bank->target;
        lpc2900_flash_bank_t *lpc2900_info = bank->driver_priv;


        status = lpc2900_is_ready(bank);
        if (status != ERROR_OK)
        {
                return status;
        }

        /* Sanity check on sector range */
        if ((first < 0) || (last < first) || (last >= bank->num_sectors))
        {
                LOG_INFO("Bad sector range");
                return ERROR_FLASH_SECTOR_INVALID;
        }

        /* Update the info about secured sectors */
        lpc2900_read_security_status( bank );

        /* The selected sector range might include secured sectors. An attempt
         * to erase such a sector will cause the erase to fail also for unsecured
         * sectors. It is necessary to determine the last unsecured sector now,
         * because we have to treat the last relevant sector in the list in
         * a special way.
         */
        last_unsecured_sector = -1;
        for (sector = first; sector <= last; sector++)
        {
                if ( !bank->sectors[sector].is_protected )
                {
                        last_unsecured_sector = sector;
                }
        }

        /* Exit now, in case of the rare constellation where all sectors in range
         * are secured. This is regarded a success, since erasing/programming of
         * secured sectors shall be handled transparently.
         */
        if ( last_unsecured_sector == -1 )
        {
                return ERROR_OK;
        }

        /* Enable flash block and set the correct CRA clock of 66 kHz */
        lpc2900_setup(bank);

        /* Clear END_OF_ERASE interrupt status */
        target_write_u32(target, INT_CLR_STATUS, INTSRC_END_OF_ERASE);

        /* Set the program/erase timer to FLASH_ERASE_TIME */
        target_write_u32(target, FPTR,
                         FPTR_EN_T | lpc2900_calc_tr( lpc2900_info->clk_sys_fmc,
                                                      FLASH_ERASE_TIME ));

        /* Sectors are marked for erasure, then erased all together */
        for (sector = first; sector <= last_unsecured_sector; sector++)
        {
                /* Only mark sectors that aren't secured. Any attempt to erase a group
                 * of sectors will fail if any single one of them is secured!
                 */
                if ( !bank->sectors[sector].is_protected )
                {
                        /* Unprotect the sector */
                        target_write_u32(target, bank->sectors[sector].offset, 0);
                        target_write_u32(target, FCTR,
                                         FCTR_FS_LOADREQ | FCTR_FS_WPB |
                                         FCTR_FS_WEB | FCTR_FS_WRE | FCTR_FS_CS);

                        /* Mark the sector for erasure. The last sector in the list
                           triggers the erasure. */
                        target_write_u32(target, bank->sectors[sector].offset, 0);
                        if ( sector == last_unsecured_sector )
                        {
                                target_write_u32(target, FCTR,
                                                 FCTR_FS_PROGREQ | FCTR_FS_WPB | FCTR_FS_CS);
                        }
                        else
                        {
                                target_write_u32(target, FCTR,
                                                 FCTR_FS_LOADREQ | FCTR_FS_WPB |
                                                 FCTR_FS_WEB | FCTR_FS_CS);
                        }
                }
        }

        /* Wait for the end of the erase operation. If it's not over after two seconds,
         * something went dreadfully wrong... :-(
         */
        if( lpc2900_wait_status(bank, INTSRC_END_OF_ERASE, 2000) != ERROR_OK )
        {
                return ERROR_FLASH_OPERATION_FAILED;
        }

        /* Normal flash operating mode */
        target_write_u32(target, FCTR, FCTR_FS_CS | FCTR_FS_WEB);

        return ERROR_OK;
}



static int lpc2900_protect(struct flash_bank_s *bank, int set, int first, int last)
{
        /* This command is not supported.
     * "Protection" in LPC2900 terms is handled transparently. Sectors will
     * automatically be unprotected as needed.
     * Instead we use the concept of sector security. A secured sector is shown
     * as "protected" in OpenOCD. Sector security is a permanent feature, and
     * cannot be disabled once activated.
     */

        return ERROR_OK;
}


/**
 * Write data to flash.
 *
 * @param bank Pointer to the flash bank descriptor
 * @param buffer Buffer with data
 * @param offset Start address (relative to bank start)
 * @param count Number of bytes to be programmed
 */
static int lpc2900_write(struct flash_bank_s *bank, uint8_t *buffer,
                         uint32_t offset, uint32_t count)
{
        uint8_t page[FLASH_PAGE_SIZE];
        uint32_t status;
        uint32_t num_bytes;
        target_t *target = bank->target;
        lpc2900_flash_bank_t *lpc2900_info = bank->driver_priv;
        int sector;
        int retval;

        static const uint32_t write_target_code[] = {
                /* Set auto latch mode: FCTR=CS|WRE|WEB */
                0xe3a0a007,   /* loop       mov r10, #0x007 */
                0xe583a000,   /*            str r10,[r3,#0] */

                /* Load complete page into latches */
                0xe3a06020,   /*            mov r6,#(512/16) */
                0xe8b00f00,   /* next       ldmia r0!,{r8-r11} */
                0xe8a10f00,   /*            stmia r1!,{r8-r11} */
                0xe2566001,   /*            subs r6,#1 */
                0x1afffffb,   /*            bne next */

                /* Clear END_OF_BURN interrupt status */
                0xe3a0a002,   /*            mov r10,#(1 << 1) */
                0xe583afe8,   /*            str r10,[r3,#0xfe8] */

                /* Set the erase time to FLASH_PROGRAM_TIME */
                0xe5834008,   /*            str r4,[r3,#8] */

                /* Trigger flash write
                        FCTR = CS | WRE | WPB | PROGREQ */
                0xe3a0a083,   /*            mov r10,#0x83 */
                0xe38aaa01,   /*            orr r10,#0x1000 */
                0xe583a000,   /*            str r10,[r3,#0] */

                /* Wait for end of burn */
                0xe593afe0,   /* wait       ldr r10,[r3,#0xfe0] */
                0xe21aa002,   /*            ands r10,#(1 << 1) */
                0x0afffffc,   /*            beq wait */

                /* End? */
                0xe2522001,   /*            subs r2,#1 */
                0x1affffed,   /*            bne loop */

                0xeafffffe    /* done       b done */
        };


        status = lpc2900_is_ready(bank);
        if (status != ERROR_OK)
        {
                return status;
        }

        /* Enable flash block and set the correct CRA clock of 66 kHz */
        lpc2900_setup(bank);

        /* Update the info about secured sectors */
        lpc2900_read_security_status( bank );

        /* Unprotect all involved sectors */
        for (sector = 0; sector < bank->num_sectors; sector++)
        {
                /* Start address in or before this sector? */
                /* End address in or behind this sector? */
                if ( ((bank->base + offset) <
                          (bank->sectors[sector].offset + bank->sectors[sector].size)) &&
                     ((bank->base + (offset + count - 1)) >= bank->sectors[sector].offset) )
                {
                        /* This sector is involved and needs to be unprotected.
                                * Don't do it for secured sectors.
                                */
                        if ( !bank->sectors[sector].is_protected )
                        {
                                target_write_u32(target, bank->sectors[sector].offset, 0);
                                target_write_u32(target, FCTR,
                                                 FCTR_FS_LOADREQ | FCTR_FS_WPB |
                                                 FCTR_FS_WEB | FCTR_FS_WRE | FCTR_FS_CS);
                        }
                }
        }

        /* Set the program/erase time to FLASH_PROGRAM_TIME */
        uint32_t prog_time = FPTR_EN_T | lpc2900_calc_tr( lpc2900_info->clk_sys_fmc,
                                                          FLASH_PROGRAM_TIME );

        /* If there is a working area of reasonable size, use it to program via
           a target algorithm. If not, fall back to host programming. */

        /* We need some room for target code. */
        uint32_t target_code_size = sizeof(write_target_code);

        /* Try working area allocation. Start with a large buffer, and try with
           reduced size if that fails. */
        working_area_t *warea;
        uint32_t buffer_size = lpc2900_info->max_ram_block - 1 * KiB;
        while( (retval = target_alloc_working_area(target,
                                                   buffer_size + target_code_size,
                                                   &warea)) != ERROR_OK )
        {
                /* Try a smaller buffer now, and stop if it's too small. */
                buffer_size -= 1 * KiB;
                if (buffer_size < 2 * KiB)
                {
                        LOG_INFO( "no (large enough) working area"
                                  ", falling back to host mode" );
                        warea = NULL;
                        break;
                }
        };

        if( warea )
        {
                reg_param_t reg_params[5];
                armv4_5_algorithm_t armv4_5_info;

                /* We can use target mode. Download the algorithm. */
                retval = target_write_buffer( target,
                                              (warea->address)+buffer_size,
                                              target_code_size,
                                              (uint8_t *)write_target_code);
                if (retval != ERROR_OK)
                {
                        LOG_ERROR("Unable to write block write code to target");
                        target_free_all_working_areas(target);
                        return ERROR_FLASH_OPERATION_FAILED;
                }

                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_OUT);
                init_reg_param(&reg_params[4], "r4", 32, PARAM_OUT);

                /* Write to flash in large blocks */
                while ( count != 0 )
                {
                        uint32_t this_npages;
                        uint8_t *this_buffer;
                        int start_sector = lpc2900_address2sector( bank, offset );

                        /* First page / last page / rest */
                        if( offset % FLASH_PAGE_SIZE )
                        {
                                /* Block doesn't start on page boundary.
                                   Burn first partial page separately. */
                                memset( &page, 0xff, sizeof(page) );
                                memcpy( &page[offset % FLASH_PAGE_SIZE],
                                        buffer,
                                        FLASH_PAGE_SIZE - (offset % FLASH_PAGE_SIZE) );
                                this_npages = 1;
                                this_buffer = &page[0];
                                count = count + (offset % FLASH_PAGE_SIZE);
                                offset = offset - (offset % FLASH_PAGE_SIZE);
                        }
                        else if( count < FLASH_PAGE_SIZE )
                        {
                                /* Download last incomplete page separately. */
                                memset( &page, 0xff, sizeof(page) );
                                memcpy( &page, buffer, count );
                                this_npages = 1;
                                this_buffer = &page[0];
                                count = FLASH_PAGE_SIZE;
                        }
                        else
                        {
                                /* Download as many full pages as possible */
                                this_npages = (count < buffer_size) ?
                                               count / FLASH_PAGE_SIZE :
                                               buffer_size / FLASH_PAGE_SIZE;
                                this_buffer = buffer;

                                /* Make sure we stop at the next secured sector */
                                int sector = start_sector + 1;
                                while( sector < bank->num_sectors )
                                {
                                        /* Secured? */
                                        if( bank->sectors[sector].is_protected )
                                        {
                                                /* Is that next sector within the current block? */
                                                if( (bank->sectors[sector].offset - bank->base) <
                                                        (offset + (this_npages * FLASH_PAGE_SIZE)) )
                                                {
                                                        /* Yes! Split the block */
                                                        this_npages =
                                                          (bank->sectors[sector].offset - bank->base - offset)
                                                              / FLASH_PAGE_SIZE;
                                                        break;
                                                }
                                        }

                                        sector++;
                                }
                        }

                        /* Skip the current sector if it is secured */
                        if (bank->sectors[start_sector].is_protected)
                        {
                                LOG_DEBUG("Skip secured sector %d",
                                                start_sector);

                                /* Stop if this is the last sector */
                                if (start_sector == bank->num_sectors - 1)
                                {
                                        break;
                                }

                                /* Skip */
                                uint32_t nskip = bank->sectors[start_sector].size -
                                                 (offset % bank->sectors[start_sector].size);
                                offset += nskip;
                                buffer += nskip;
                                count = (count >= nskip) ? (count - nskip) : 0;
                                continue;
                        }

                        /* Execute buffer download */
                        if ((retval = target_write_buffer(target,
                                                          warea->address,
                                                          this_npages * FLASH_PAGE_SIZE,
                                                          this_buffer)) != ERROR_OK)
                        {
                                LOG_ERROR("Unable to write data to target");
                                target_free_all_working_areas(target);
                                return ERROR_FLASH_OPERATION_FAILED;
                        }

                        /* Prepare registers */
                        buf_set_u32(reg_params[0].value, 0, 32, warea->address);
                        buf_set_u32(reg_params[1].value, 0, 32, offset);
                        buf_set_u32(reg_params[2].value, 0, 32, this_npages);
                        buf_set_u32(reg_params[3].value, 0, 32, FCTR);
                        buf_set_u32(reg_params[4].value, 0, 32, FPTR_EN_T | prog_time);

                        /* Execute algorithm, assume breakpoint for last instruction */
                        armv4_5_info.common_magic = ARMV4_5_COMMON_MAGIC;
                        armv4_5_info.core_mode = ARMV4_5_MODE_SVC;
                        armv4_5_info.core_state = ARMV4_5_STATE_ARM;

                        retval = target_run_algorithm(target, 0, NULL, 5, reg_params,
                                (warea->address) + buffer_size,
                                (warea->address) + buffer_size + target_code_size - 4,
                                10000, /* 10s should be enough for max. 16 KiB of data */
                                &armv4_5_info);

                        if (retval != ERROR_OK)
                        {
                                LOG_ERROR("Execution of flash algorithm failed.");
                                target_free_all_working_areas(target);
                                retval = ERROR_FLASH_OPERATION_FAILED;
                                break;
                        }

                        count -= this_npages * FLASH_PAGE_SIZE;
                        buffer += this_npages * FLASH_PAGE_SIZE;
                        offset += this_npages * FLASH_PAGE_SIZE;
                }

                /* Free all resources */
                destroy_reg_param(&reg_params[0]);
                destroy_reg_param(&reg_params[1]);
                destroy_reg_param(&reg_params[2]);
                destroy_reg_param(&reg_params[3]);
                destroy_reg_param(&reg_params[4]);
                target_free_all_working_areas(target);
        }
        else
        {
                /* Write to flash memory page-wise */
                while ( count != 0 )
                {
                        /* How many bytes do we copy this time? */
                        num_bytes = (count >= FLASH_PAGE_SIZE) ?
                                    FLASH_PAGE_SIZE - (offset % FLASH_PAGE_SIZE) :
                                    count;

                        /* Don't do anything with it if the page is in a secured sector. */
                        if ( !bank->sectors[lpc2900_address2sector(bank, offset)].is_protected )
                        {
                                /* Set latch load mode */
                                target_write_u32(target, FCTR,
                                                 FCTR_FS_CS | FCTR_FS_WRE | FCTR_FS_WEB);

                                /* Always clear the buffer (a little overhead, but who cares) */
                                memset(page, 0xFF, FLASH_PAGE_SIZE);

                                /* Copy them to the buffer */
                                memcpy( &page[offset % FLASH_PAGE_SIZE],
                                        &buffer[offset % FLASH_PAGE_SIZE],
                                        num_bytes );

                                /* Write whole page to flash data latches */
                                if (target_write_memory(
                                                 target,
                                                 bank->base + (offset - (offset % FLASH_PAGE_SIZE)),
                                                 4, FLASH_PAGE_SIZE / 4, page) != ERROR_OK)
                                {
                                        LOG_ERROR("Write failed @ 0x%8.8" PRIx32, offset);
                                        target_write_u32(target, FCTR, FCTR_FS_CS | FCTR_FS_WEB);

                                        return ERROR_FLASH_OPERATION_FAILED;
                                }

                                /* Clear END_OF_BURN interrupt status */
                                target_write_u32(target, INT_CLR_STATUS, INTSRC_END_OF_BURN);

                                /* Set the programming time */
                                target_write_u32(target, FPTR, FPTR_EN_T | prog_time);

                                /* Trigger flash write */
                                target_write_u32(target, FCTR,
                                    FCTR_FS_CS | FCTR_FS_WRE | FCTR_FS_WPB | FCTR_FS_PROGREQ);

                                /* Wait for the end of the write operation. If it's not over
                                 * after one second, something went dreadfully wrong... :-(
                                 */
                                if (lpc2900_wait_status(bank, INTSRC_END_OF_BURN, 1000) != ERROR_OK)
                                {
                                        LOG_ERROR("Write failed @ 0x%8.8" PRIx32, offset);
                                        target_write_u32(target, FCTR, FCTR_FS_CS | FCTR_FS_WEB);

                                        return ERROR_FLASH_OPERATION_FAILED;
                                }
                        }

                        /* Update pointers and counters */
                        offset += num_bytes;
                        buffer += num_bytes;
                        count -= num_bytes;
                }

                retval = ERROR_OK;
        }

        /* Normal flash operating mode */
        target_write_u32(target, FCTR, FCTR_FS_CS | FCTR_FS_WEB);

        return retval;
}


/**
 * Try and identify the device.
 *
 * Determine type number and its memory layout.
 *
 * @param bank Pointer to the flash bank descriptor
 */
static int lpc2900_probe(struct flash_bank_s *bank)
{
        lpc2900_flash_bank_t *lpc2900_info = bank->driver_priv;
        target_t *target = bank->target;
        int i = 0;
        uint32_t offset;


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

        /* We want to do this only once. Check if we already have a valid CHIPID,
         * because then we will have already successfully probed the device.
         */
        if (lpc2900_info->chipid == EXPECTED_CHIPID)
        {
                return ERROR_OK;
        }

        /* Probing starts with reading the CHIPID register. We will continue only
         * if this identifies as an LPC2900 device.
         */
        target_read_u32(target, CHIPID, &lpc2900_info->chipid);

        if (lpc2900_info->chipid != EXPECTED_CHIPID)
        {
                LOG_WARNING("Device is not an LPC29xx");
                return ERROR_FLASH_OPERATION_FAILED;
        }

        /* It's an LPC29xx device. Now read the feature register FEAT0...FEAT3. */
        uint32_t feat0, feat1, feat2, feat3;
        target_read_u32(target, FEAT0, &feat0);
        target_read_u32(target, FEAT1, &feat1);
        target_read_u32(target, FEAT2, &feat2);
        target_read_u32(target, FEAT3, &feat3);

        /* Base address */
        bank->base = 0x20000000;

        /* Determine flash layout from FEAT2 register */
        uint32_t num_64k_sectors = (feat2 >> 16) & 0xFF;
        uint32_t num_8k_sectors = (feat2 >> 0) & 0xFF;
        bank->num_sectors = num_64k_sectors + num_8k_sectors;
        bank->size = KiB * (64 * num_64k_sectors + 8 * num_8k_sectors);

        /* Determine maximum contiguous RAM block */
        lpc2900_info->max_ram_block = 16 * KiB;
        if( (feat1 & 0x30) == 0x30 )
        {
                lpc2900_info->max_ram_block = 32 * KiB;
                if( (feat1 & 0x0C) == 0x0C )
                {
                        lpc2900_info->max_ram_block = 48 * KiB;
                }
        }

        /* Determine package code and ITCM size */
        uint32_t package_code = feat0 & 0x0F;
        uint32_t itcm_code = (feat1 >> 16) & 0x1F;

        /* Determine the exact type number. */
        uint32_t found = 1;
        if ( (package_code == 4) && (itcm_code == 5) )
        {
                /* Old LPC2917 or LPC2919 (non-/01 devices) */
                lpc2900_info->target_name = (bank->size == 768*KiB) ? "LPC2919" : "LPC2917";
        }
        else
        {
                if ( package_code == 2 )
                {
                        /* 100-pin package */
                        if ( bank->size == 128*KiB )
                        {
                                lpc2900_info->target_name = "LPC2921";
                        }
                        else if ( bank->size == 256*KiB )
                        {
                                lpc2900_info->target_name = "LPC2923";
                        }
                        else if ( bank->size == 512*KiB )
                        {
                                lpc2900_info->target_name = "LPC2925";
                        }
                        else
                        {
                                found = 0;
                        }
                }
                else if ( package_code == 4 )
                {
                        /* 144-pin package */
                        if ( (bank->size == 512*KiB) && (feat3 == 0xFFFFFCF0) )
                        {
                                lpc2900_info->target_name = "LPC2917/01";
                        }
                        else if ( (bank->size == 512*KiB) && (feat3 == 0xFFFFFFF1) )
                        {
                                lpc2900_info->target_name = "LPC2927";
                        }
                        else if ( (bank->size == 768*KiB) && (feat3 == 0xFFFFFCF8) )
                        {
                                lpc2900_info->target_name = "LPC2919/01";
                        }
                        else if ( (bank->size == 768*KiB) && (feat3 == 0xFFFFFFF9) )
                        {
                                lpc2900_info->target_name = "LPC2929";
                        }
                        else
                        {
                                found = 0;
                        }
                }
                else if ( package_code == 5 )
                {
                        /* 208-pin package */
                        lpc2900_info->target_name = (bank->size == 0) ? "LPC2930" : "LPC2939";
                }
                else
                {
                        found = 0;
                }
        }

        if ( !found )
        {
                LOG_WARNING("Unknown LPC29xx derivative");
                return ERROR_FLASH_OPERATION_FAILED;
        }

        /* Show detected device */
        LOG_INFO("Flash bank %d"
                 ": Device %s, %" PRIu32
                 " KiB in %d sectors",
                 bank->bank_number,
                 lpc2900_info->target_name, bank->size / KiB,
                 bank->num_sectors);

        /* Flashless devices cannot be handled */
        if ( bank->num_sectors == 0 )
        {
                LOG_WARNING("Flashless device cannot be handled");
                return ERROR_FLASH_OPERATION_FAILED;
        }

        /* Sector layout.
         * These are logical sector numbers. When doing real flash operations,
         * the logical flash number are translated into the physical flash numbers
         * of the device.
         */
        bank->sectors = malloc(sizeof(flash_sector_t) * bank->num_sectors);

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

                if ( i <= 7 )
                {
                        bank->sectors[i].size = 8 * KiB;
                }
                else if ( i <= 18 )
                {
                        bank->sectors[i].size = 64 * KiB;
                }
                else
                {
                        /* We shouldn't come here. But there might be a new part out there
                         * that has more than 19 sectors. Politely ask for a fix then.
                         */
                        bank->sectors[i].size = 0;
                        LOG_ERROR("Never heard about sector %d", i);
                }

                offset += bank->sectors[i].size;
        }

        /* Read sector security status */
        if ( lpc2900_read_security_status(bank) != ERROR_OK )
        {
                LOG_ERROR("Cannot determine sector security status");
                return ERROR_FLASH_OPERATION_FAILED;
        }

        return ERROR_OK;
}


/**
 * Run a blank check for each sector.
 *
 * For speed reasons, the device isn't read word by word.
 * A hash value is calculated by the hardware ("BIST") for each sector.
 * This value is then compared against the known hash of an empty sector.
 *
 * @param bank Pointer to the flash bank descriptor
 */
static int lpc2900_erase_check(struct flash_bank_s *bank)
{
        uint32_t status = lpc2900_is_ready(bank);
        if (status != ERROR_OK)
        {
                LOG_INFO("Processor not halted/not probed");
                return status;
        }

        /* Use the BIST (Built-In Selft Test) to generate a signature of each flash
         * sector. Compare against the expected signature of an empty sector.
         */
        int sector;
        for ( sector = 0; sector < bank->num_sectors; sector++ )
        {
                uint32_t signature[4];
                if ( (status = lpc2900_run_bist128( bank,
                                                    bank->sectors[sector].offset,
                                                    bank->sectors[sector].offset +
                                                       (bank->sectors[sector].size - 1),
                                                    &signature)) != ERROR_OK )
                {
                        return status;
                }

                /* The expected signatures for an empty sector are different
                 * for 8 KiB and 64 KiB sectors.
                 */
                if ( bank->sectors[sector].size == 8*KiB )
                {
                        bank->sectors[sector].is_erased =
                            (signature[3] == 0x01ABAAAA) &&
                            (signature[2] == 0xAAAAAAAA) &&
                            (signature[1] == 0xAAAAAAAA) &&
                            (signature[0] == 0xAAA00AAA);
                }
                if ( bank->sectors[sector].size == 64*KiB )
                {
                        bank->sectors[sector].is_erased =
                            (signature[3] == 0x11801222) &&
                            (signature[2] == 0xB88844FF) &&
                            (signature[1] == 0x11A22008) &&
                            (signature[0] == 0x2B1BFE44);
                }
        }

        return ERROR_OK;
}


/**
 * Get protection (sector security) status.
 *
 * Determine the status of "sector security" for each sector.
 * A secured sector is one that can never be erased/programmed again.
 *
 * @param bank Pointer to the flash bank descriptor
 */
static int lpc2900_protect_check(struct flash_bank_s *bank)
{
        return lpc2900_read_security_status(bank);
}


/**
 * Print info about the driver (not the device).
 *
 * @param bank Pointer to the flash bank descriptor
 * @param buf Buffer to take the string
 * @param buf_size Maximum number of characters that the buffer can take
 */
static int lpc2900_info(struct flash_bank_s *bank, char *buf, int buf_size)
{
        snprintf(buf, buf_size, "lpc2900 flash driver");

        return ERROR_OK;
}


flash_driver_t lpc2900_flash =
{
        .name               = "lpc2900",
        .register_commands  = lpc2900_register_commands,
        .flash_bank_command = lpc2900_flash_bank_command,
        .erase              = lpc2900_erase,
        .protect            = lpc2900_protect,
        .write              = lpc2900_write,
        .probe              = lpc2900_probe,
        .auto_probe         = lpc2900_probe,
        .erase_check        = lpc2900_erase_check,
        .protect_check      = lpc2900_protect_check,
        .info               = lpc2900_info
};