[karo-tx-linux.git] / drivers / mtd / nand / gpmi-nfc / gpmi-nfc.c

/*
 * Freescale GPMI NFC NAND Flash Driver
 *
 * Copyright (C) 2010-2011 Freescale Semiconductor, Inc.
 * Copyright (C) 2008 Embedded Alley Solutions, Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
#include <linux/slab.h>
#include "gpmi-nfc.h"

/* add our owner bbt descriptor */
static uint8_t scan_ff_pattern[] = { 0xff };
static struct nand_bbt_descr gpmi_bbt_descr = {
        .options        = 0,
        .offs           = 0,
        .len            = 1,
        .pattern        = scan_ff_pattern
};

/* debug control */
int gpmi_debug;
module_param(gpmi_debug, int, 0644);
MODULE_PARM_DESC(gpmi_debug, "print out the debug infomation.");

static ssize_t show_ignorebad(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct gpmi_nfc_data *this = dev_get_drvdata(dev);
        struct mil *mil = &this->mil;

        return sprintf(buf, "%d\n", mil->ignore_bad_block_marks);
}

static ssize_t
store_ignorebad(struct device *dev, struct device_attribute *attr,
                        const char *buf, size_t size)
{
        struct gpmi_nfc_data *this = dev_get_drvdata(dev);
        struct mil *mil = &this->mil;
        const char *p = buf;
        unsigned long v;

        if (strict_strtoul(p, 0, &v) < 0)
                return -EINVAL;

        if (v > 0)
                v = 1;

        if (v != mil->ignore_bad_block_marks) {
                if (v) {
                        /*
                         * This will cause the NAND Flash MTD code to believe
                         * that it never created a BBT and force it to call our
                         * block_bad function.
                         *
                         * See mil_block_bad for more details.
                         */
                        mil->saved_bbt = mil->nand.bbt;
                        mil->nand.bbt  = NULL;
                } else {
                        /*
                         * Restore the NAND Flash MTD's pointer
                         * to its in-memory BBT.
                         */
                        mil->nand.bbt = mil->saved_bbt;
                }
                mil->ignore_bad_block_marks = v;
        }
        return size;
}

static DEVICE_ATTR(ignorebad, 0644, show_ignorebad, store_ignorebad);
static struct device_attribute *device_attributes[] = {
        &dev_attr_ignorebad,
};

static irqreturn_t bch_irq(int irq, void *cookie)
{
        struct gpmi_nfc_data *this = cookie;
        struct nfc_hal *nfc = this->nfc;

        /* Clear the BCH interrupt */
        nfc->clear_bch(this);

        complete(&nfc->bch_done);
        return IRQ_HANDLED;
}

/* calculate the ECC strength by hand */
static inline int get_ecc_strength(struct gpmi_nfc_data *this)
{
        struct mtd_info *mtd = &this->mil.mtd;
        int ecc_strength = 0;

        switch (mtd->writesize) {
        case 2048:
                ecc_strength = 8;
                break;
        case 4096:
                switch (mtd->oobsize) {
                case 128:
                        ecc_strength = 8;
                        break;
                case 224:
                case 218:
                        ecc_strength = 16;
                        break;
                }
                break;
        case 8192:
                ecc_strength = 24;
                break;
        }

        return ecc_strength;
}

bool is_ddr_nand(struct gpmi_nfc_data *this)
{
        struct nand_chip *chip = &this->mil.nand;

        /* ONFI nand */
        if (chip->onfi_version != 0)
                return true;

        /* TOGGLE nand */

        return false;
}

static inline int get_ecc_chunk_size(struct gpmi_nfc_data *this)
{
        /* the ONFI/TOGGLE nands use 1k ecc chunk size */
        if (is_ddr_nand(this))
                return 1024;

        /* for historical reason */
        return 512;
}

int common_nfc_set_geometry(struct gpmi_nfc_data *this)
{
        struct nfc_geometry *geo = &this->nfc_geometry;
        struct mtd_info *mtd = &this->mil.mtd;
        unsigned int metadata_size;
        unsigned int status_size;
        unsigned int chunk_data_size_in_bits;
        unsigned int chunk_ecc_size_in_bits;
        unsigned int chunk_total_size_in_bits;
        unsigned int block_mark_chunk_number;
        unsigned int block_mark_chunk_bit_offset;
        unsigned int block_mark_bit_offset;

        /* We only support BCH now. */
        geo->ecc_algorithm = "BCH";

        /*
         * We always choose a metadata size of 10. Don't try to make sense of
         * it -- this is really only for historical compatibility.
         */
        geo->metadata_size_in_bytes = 10;

        /* ECC chunks */
        geo->ecc_chunk_size_in_bytes = get_ecc_chunk_size(this);

        /*
         * Compute the total number of ECC chunks in a page. This includes the
         * slightly larger chunk at the beginning of the page, which contains
         * both data and metadata.
         */
        geo->ecc_chunk_count = mtd->writesize / geo->ecc_chunk_size_in_bytes;

        /*
         * We use the same ECC strength for all chunks, including the first one.
         */
        geo->ecc_strength = get_ecc_strength(this);
        if (!geo->ecc_strength) {
                pr_info("Page size:%d, OOB:%d\n", mtd->writesize, mtd->oobsize);
                return -EINVAL;
        }

        /* Compute the page size, include page and oob. */
        geo->page_size_in_bytes = mtd->writesize + mtd->oobsize;

        /*
         * ONFI/TOGGLE nand needs GF14, so re-calculate DMA page size.
         * The ONFI nand must do the recalculation,
         * else it will fail in DMA in some platform(such as imx50).
         */
        if (is_ddr_nand(this))
                geo->page_size_in_bytes = mtd->writesize +
                                geo->metadata_size_in_bytes +
                        (geo->ecc_strength * 14 * 8 / geo->ecc_chunk_count);

        geo->payload_size_in_bytes = mtd->writesize;
        /*
         * In principle, computing the auxiliary buffer geometry is NFC
         * version-specific. However, at this writing, all versions share the
         * same model, so this code can also be shared.
         *
         * The auxiliary buffer contains the metadata and the ECC status. The
         * metadata is padded to the nearest 32-bit boundary. The ECC status
         * contains one byte for every ECC chunk, and is also padded to the
         * nearest 32-bit boundary.
         */
        metadata_size = ALIGN(geo->metadata_size_in_bytes, 4);
        status_size   = ALIGN(geo->ecc_chunk_count, 4);

        geo->auxiliary_size_in_bytes = metadata_size + status_size;
        geo->auxiliary_status_offset = metadata_size;

        /* Check if we're going to do block mark swapping. */
        if (!this->swap_block_mark)
                return 0;

        /*
         * If control arrives here, we're doing block mark swapping, so we need
         * to compute the byte and bit offsets of the physical block mark within
         * the ECC-based view of the page data. In principle, this isn't a
         * difficult computation -- but it's very important and it's easy to get
         * it wrong, so we do it carefully.
         *
         * Note that this calculation is simpler because we use the same ECC
         * strength for all chunks, including the zero'th one, which contains
         * the metadata. The calculation would be slightly more complicated
         * otherwise.
         *
         * We start by computing the physical bit offset of the block mark. We
         * then subtract the number of metadata and ECC bits appearing before
         * the mark to arrive at its bit offset within the data alone.
         */

        /* Compute some important facts about chunk geometry. */
        chunk_data_size_in_bits = geo->ecc_chunk_size_in_bytes * 8;

        /* ONFI/TOGGLE nand needs GF14 */
        if (is_ddr_nand(this))
                chunk_ecc_size_in_bits  = geo->ecc_strength * 14;
        else
                chunk_ecc_size_in_bits  = geo->ecc_strength * 13;

        chunk_total_size_in_bits =
                        chunk_data_size_in_bits + chunk_ecc_size_in_bits;

        /* Compute the bit offset of the block mark within the physical page. */
        block_mark_bit_offset = mtd->writesize * 8;

        /* Subtract the metadata bits. */
        block_mark_bit_offset -= geo->metadata_size_in_bytes * 8;

        /*
         * Compute the chunk number (starting at zero) in which the block mark
         * appears.
         */
        block_mark_chunk_number =
                        block_mark_bit_offset / chunk_total_size_in_bits;

        /*
         * Compute the bit offset of the block mark within its chunk, and
         * validate it.
         */
        block_mark_chunk_bit_offset =
                block_mark_bit_offset -
                        (block_mark_chunk_number * chunk_total_size_in_bits);

        if (block_mark_chunk_bit_offset > chunk_data_size_in_bits) {
                /*
                 * If control arrives here, the block mark actually appears in
                 * the ECC bits of this chunk. This wont' work.
                 */
                pr_info("Unsupported page geometry : %u:%u\n",
                                mtd->writesize, mtd->oobsize);
                return -EINVAL;
        }

        /*
         * Now that we know the chunk number in which the block mark appears,
         * we can subtract all the ECC bits that appear before it.
         */
        block_mark_bit_offset -=
                        block_mark_chunk_number * chunk_ecc_size_in_bits;

        /*
         * We now know the absolute bit offset of the block mark within the
         * ECC-based data. We can now compute the byte offset and the bit
         * offset within the byte.
         */
        geo->block_mark_byte_offset = block_mark_bit_offset / 8;
        geo->block_mark_bit_offset  = block_mark_bit_offset % 8;

        return 0;
}

struct dma_chan *get_dma_chan(struct gpmi_nfc_data *this)
{
        int chip = this->mil.current_chip;

        BUG_ON(chip < 0);
        return this->dma_chans[chip];
}

/* Can we use the upper's buffer directly for DMA? */
void prepare_data_dma(struct gpmi_nfc_data *this, enum dma_data_direction dr)
{
        struct mil *mil = &this->mil;
        struct scatterlist *sgl = &mil->data_sgl;
        int ret;

        mil->direct_dma_map_ok = true;

        /* first try to map the upper buffer directly */
        sg_init_one(sgl, mil->upper_buf, mil->upper_len);
        ret = dma_map_sg(this->dev, sgl, 1, dr);
        if (ret == 0) {
                /* We have to use our own DMA buffer. */
                sg_init_one(sgl, mil->data_buffer_dma, PAGE_SIZE);

                if (dr == DMA_TO_DEVICE)
                        memcpy(mil->data_buffer_dma, mil->upper_buf,
                                mil->upper_len);

                ret = dma_map_sg(this->dev, sgl, 1, dr);
                BUG_ON(ret == 0);

                mil->direct_dma_map_ok = false;
        }
}

/* This will be called after the DMA operation is finished. */
static void dma_irq_callback(void *param)
{
        struct gpmi_nfc_data *this = param;
        struct nfc_hal *nfc = this->nfc;
        struct mil *mil = &this->mil;

        complete(&nfc->dma_done);

        switch (this->dma_type) {
        case DMA_FOR_COMMAND:
                dma_unmap_sg(this->dev, &mil->cmd_sgl, 1, DMA_TO_DEVICE);
                break;

        case DMA_FOR_READ_DATA:
                dma_unmap_sg(this->dev, &mil->data_sgl, 1, DMA_FROM_DEVICE);
                if (mil->direct_dma_map_ok == false)
                        memcpy(mil->upper_buf, mil->data_buffer_dma,
                                mil->upper_len);
                break;

        case DMA_FOR_WRITE_DATA:
                dma_unmap_sg(this->dev, &mil->data_sgl, 1, DMA_TO_DEVICE);
                break;

        case DMA_FOR_READ_ECC_PAGE:
        case DMA_FOR_WRITE_ECC_PAGE:
                /* We have to wait the BCH interrupt to finish. */
                break;

        default:
                BUG();
        }
}

int start_dma_without_bch_irq(struct gpmi_nfc_data *this,
                                struct dma_async_tx_descriptor *desc)
{
        struct nfc_hal *nfc = this->nfc;
        int err;

        init_completion(&nfc->dma_done);

        desc->callback          = dma_irq_callback;
        desc->callback_param    = this;
        dmaengine_submit(desc);

        /* Wait for the interrupt from the DMA block. */
        err = wait_for_completion_timeout(&nfc->dma_done,
                                        msecs_to_jiffies(1000));
        err = (!err) ? -ETIMEDOUT : 0;
        if (err)
                pr_info("DMA timeout!!!\n");
        return err;
}

/*
 * This function is used in BCH reading or BCH writing pages.
 * It will wait for the BCH interrupt as long as ONE second.
 * Actually, we must wait for two interrupts :
 *      [1] firstly the DMA interrupt and
 *      [2] secondly the BCH interrupt.
 *
 * @this:       Per-device data structure.
 * @desc:       DMA channel
 */
int start_dma_with_bch_irq(struct gpmi_nfc_data *this,
                        struct dma_async_tx_descriptor *desc)
{
        struct nfc_hal *nfc = this->nfc;
        int err;

        /* Prepare to receive an interrupt from the BCH block. */
        init_completion(&nfc->bch_done);

        /* start the DMA */
        start_dma_without_bch_irq(this, desc);

        /* Wait for the interrupt from the BCH block. */
        err = wait_for_completion_timeout(&nfc->bch_done,
                                        msecs_to_jiffies(1000));
        err = (!err) ? -ETIMEDOUT : 0;
        if (err)
                pr_info("bch timeout!!!\n");
        return err;
}

/**
 * ns_to_cycles - Converts time in nanoseconds to cycles.
 *
 * @ntime:   The time, in nanoseconds.
 * @period:  The cycle period, in nanoseconds.
 * @min:     The minimum allowable number of cycles.
 */
static unsigned int ns_to_cycles(unsigned int time,
                                        unsigned int period, unsigned int min)
{
        unsigned int k;

        /*
         * Compute the minimum number of cycles that entirely contain the
         * given time.
         */
        k = (time + period - 1) / period;
        return max(k, min);
}

/**
 * gpmi_compute_hardware_timing - Apply timing to current hardware conditions.
 *
 * @this:             Per-device data.
 * @hardware_timing:  A pointer to a hardware timing structure that will receive
 *                    the results of our calculations.
 */
int gpmi_nfc_compute_hardware_timing(struct gpmi_nfc_data *this,
                                        struct gpmi_nfc_hardware_timing *hw)
{
        struct gpmi_nfc_platform_data *pdata = this->pdata;
        struct nfc_hal *nfc = this->nfc;
        struct nand_chip *nand = &this->mil.nand;
        struct nand_timing target = nfc->timing;
        bool improved_timing_is_available;
        unsigned long clock_frequency_in_hz;
        unsigned int clock_period_in_ns;
        bool dll_use_half_periods;
        unsigned int dll_delay_shift;
        unsigned int max_sample_delay_in_ns;
        unsigned int address_setup_in_cycles;
        unsigned int data_setup_in_ns;
        unsigned int data_setup_in_cycles;
        unsigned int data_hold_in_cycles;
        int ideal_sample_delay_in_ns;
        unsigned int sample_delay_factor;
        int tEYE;
        unsigned int min_prop_delay_in_ns = pdata->min_prop_delay_in_ns;
        unsigned int max_prop_delay_in_ns = pdata->max_prop_delay_in_ns;

        /*
         * If there are multiple chips, we need to relax the timings to allow
         * for signal distortion due to higher capacitance.
         */
        if (nand->numchips > 2) {
                target.data_setup_in_ns    += 10;
                target.data_hold_in_ns     += 10;
                target.address_setup_in_ns += 10;
        } else if (nand->numchips > 1) {
                target.data_setup_in_ns    += 5;
                target.data_hold_in_ns     += 5;
                target.address_setup_in_ns += 5;
        }

        /* Check if improved timing information is available. */
        improved_timing_is_available =
                (target.tREA_in_ns  >= 0) &&
                (target.tRLOH_in_ns >= 0) &&
                (target.tRHOH_in_ns >= 0) ;

        /* Inspect the clock. */
        clock_frequency_in_hz = nfc->clock_frequency_in_hz;
        clock_period_in_ns    = 1000000000 / clock_frequency_in_hz;

        /*
         * The NFC quantizes setup and hold parameters in terms of clock cycles.
         * Here, we quantize the setup and hold timing parameters to the
         * next-highest clock period to make sure we apply at least the
         * specified times.
         *
         * For data setup and data hold, the hardware interprets a value of zero
         * as the largest possible delay. This is not what's intended by a zero
         * in the input parameter, so we impose a minimum of one cycle.
         */
        data_setup_in_cycles    = ns_to_cycles(target.data_setup_in_ns,
                                                        clock_period_in_ns, 1);
        data_hold_in_cycles     = ns_to_cycles(target.data_hold_in_ns,
                                                        clock_period_in_ns, 1);
        address_setup_in_cycles = ns_to_cycles(target.address_setup_in_ns,
                                                        clock_period_in_ns, 0);

        /*
         * The clock's period affects the sample delay in a number of ways:
         *
         * (1) The NFC HAL tells us the maximum clock period the sample delay
         *     DLL can tolerate. If the clock period is greater than half that
         *     maximum, we must configure the DLL to be driven by half periods.
         *
         * (2) We need to convert from an ideal sample delay, in ns, to a
         *     "sample delay factor," which the NFC uses. This factor depends on
         *     whether we're driving the DLL with full or half periods.
         *     Paraphrasing the reference manual:
         *
         *         AD = SDF x 0.125 x RP
         *
         * where:
         *
         *     AD   is the applied delay, in ns.
         *     SDF  is the sample delay factor, which is dimensionless.
         *     RP   is the reference period, in ns, which is a full clock period
         *          if the DLL is being driven by full periods, or half that if
         *          the DLL is being driven by half periods.
         *
         * Let's re-arrange this in a way that's more useful to us:
         *
         *                        8
         *         SDF  =  AD x ----
         *                       RP
         *
         * The reference period is either the clock period or half that, so this
         * is:
         *
         *                        8       AD x DDF
         *         SDF  =  AD x -----  =  --------
         *                      f x P        P
         *
         * where:
         *
         *       f  is 1 or 1/2, depending on how we're driving the DLL.
         *       P  is the clock period.
         *     DDF  is the DLL Delay Factor, a dimensionless value that
         *          incorporates all the constants in the conversion.
         *
         * DDF will be either 8 or 16, both of which are powers of two. We can
         * reduce the cost of this conversion by using bit shifts instead of
         * multiplication or division. Thus:
         *
         *                 AD << DDS
         *         SDF  =  ---------
         *                     P
         *
         *     or
         *
         *         AD  =  (SDF >> DDS) x P
         *
         * where:
         *
         *     DDS  is the DLL Delay Shift, the logarithm to base 2 of the DDF.
         */
        if (clock_period_in_ns > (nfc->max_dll_clock_period_in_ns >> 1)) {
                dll_use_half_periods = true;
                dll_delay_shift      = 3 + 1;
        } else {
                dll_use_half_periods = false;
                dll_delay_shift      = 3;
        }

        /*
         * Compute the maximum sample delay the NFC allows, under current
         * conditions. If the clock is running too slowly, no sample delay is
         * possible.
         */
        if (clock_period_in_ns > nfc->max_dll_clock_period_in_ns)
                max_sample_delay_in_ns = 0;
        else {
                /*
                 * Compute the delay implied by the largest sample delay factor
                 * the NFC allows.
                 */
                max_sample_delay_in_ns =
                        (nfc->max_sample_delay_factor * clock_period_in_ns) >>
                                                                dll_delay_shift;

                /*
                 * Check if the implied sample delay larger than the NFC
                 * actually allows.
                 */
                if (max_sample_delay_in_ns > nfc->max_dll_delay_in_ns)
                        max_sample_delay_in_ns = nfc->max_dll_delay_in_ns;
        }

        /*
         * Check if improved timing information is available. If not, we have to
         * use a less-sophisticated algorithm.
         */
        if (!improved_timing_is_available) {
                /*
                 * Fold the read setup time required by the NFC into the ideal
                 * sample delay.
                 */
                ideal_sample_delay_in_ns = target.gpmi_sample_delay_in_ns +
                                                nfc->internal_data_setup_in_ns;

                /*
                 * The ideal sample delay may be greater than the maximum
                 * allowed by the NFC. If so, we can trade off sample delay time
                 * for more data setup time.
                 *
                 * In each iteration of the following loop, we add a cycle to
                 * the data setup time and subtract a corresponding amount from
                 * the sample delay until we've satisified the constraints or
                 * can't do any better.
                 */
                while ((ideal_sample_delay_in_ns > max_sample_delay_in_ns) &&
                        (data_setup_in_cycles < nfc->max_data_setup_cycles)) {

                        data_setup_in_cycles++;
                        ideal_sample_delay_in_ns -= clock_period_in_ns;

                        if (ideal_sample_delay_in_ns < 0)
                                ideal_sample_delay_in_ns = 0;

                }

                /*
                 * Compute the sample delay factor that corresponds most closely
                 * to the ideal sample delay. If the result is too large for the
                 * NFC, use the maximum value.
                 *
                 * Notice that we use the ns_to_cycles function to compute the
                 * sample delay factor. We do this because the form of the
                 * computation is the same as that for calculating cycles.
                 */
                sample_delay_factor =
                        ns_to_cycles(
                                ideal_sample_delay_in_ns << dll_delay_shift,
                                                        clock_period_in_ns, 0);

                if (sample_delay_factor > nfc->max_sample_delay_factor)
                        sample_delay_factor = nfc->max_sample_delay_factor;

                /* Skip to the part where we return our results. */
                goto return_results;
        }

        /*
         * If control arrives here, we have more detailed timing information,
         * so we can use a better algorithm.
         */

        /*
         * Fold the read setup time required by the NFC into the maximum
         * propagation delay.
         */
        max_prop_delay_in_ns += nfc->internal_data_setup_in_ns;

        /*
         * Earlier, we computed the number of clock cycles required to satisfy
         * the data setup time. Now, we need to know the actual nanoseconds.
         */
        data_setup_in_ns = clock_period_in_ns * data_setup_in_cycles;

        /*
         * Compute tEYE, the width of the data eye when reading from the NAND
         * Flash. The eye width is fundamentally determined by the data setup
         * time, perturbed by propagation delays and some characteristics of the
         * NAND Flash device.
         *
         * start of the eye = max_prop_delay + tREA
         * end of the eye   = min_prop_delay + tRHOH + data_setup
         */
        tEYE = (int)min_prop_delay_in_ns + (int)target.tRHOH_in_ns +
                                                        (int)data_setup_in_ns;

        tEYE -= (int)max_prop_delay_in_ns + (int)target.tREA_in_ns;

        /*
         * The eye must be open. If it's not, we can try to open it by
         * increasing its main forcer, the data setup time.
         *
         * In each iteration of the following loop, we increase the data setup
         * time by a single clock cycle. We do this until either the eye is
         * open or we run into NFC limits.
         */
        while ((tEYE <= 0) &&
                        (data_setup_in_cycles < nfc->max_data_setup_cycles)) {
                /* Give a cycle to data setup. */
                data_setup_in_cycles++;
                /* Synchronize the data setup time with the cycles. */
                data_setup_in_ns += clock_period_in_ns;
                /* Adjust tEYE accordingly. */
                tEYE += clock_period_in_ns;
        }

        /*
         * When control arrives here, the eye is open. The ideal time to sample
         * the data is in the center of the eye:
         *
         *     end of the eye + start of the eye
         *     ---------------------------------  -  data_setup
         *                    2
         *
         * After some algebra, this simplifies to the code immediately below.
         */
        ideal_sample_delay_in_ns =
                ((int)max_prop_delay_in_ns +
                        (int)target.tREA_in_ns +
                                (int)min_prop_delay_in_ns +
                                        (int)target.tRHOH_in_ns -
                                                (int)data_setup_in_ns) >> 1;

        /*
         * The following figure illustrates some aspects of a NAND Flash read:
         *
         *
         *           __                   _____________________________________
         * RDN         \_________________/
         *
         *                                         <---- tEYE ----->
         *                                        /-----------------\
         * Read Data ----------------------------<                   >---------
         *                                        \-----------------/
         *             ^                 ^                 ^              ^
         *             |                 |                 |              |
         *             |<--Data Setup -->|<--Delay Time -->|              |
         *             |                 |                 |              |
         *             |                 |                                |
         *             |                 |<--   Quantized Delay Time   -->|
         *             |                 |                                |
         *
         *
         * We have some issues we must now address:
         *
         * (1) The *ideal* sample delay time must not be negative. If it is, we
         *     jam it to zero.
         *
         * (2) The *ideal* sample delay time must not be greater than that
         *     allowed by the NFC. If it is, we can increase the data setup
         *     time, which will reduce the delay between the end of the data
         *     setup and the center of the eye. It will also make the eye
         *     larger, which might help with the next issue...
         *
         * (3) The *quantized* sample delay time must not fall either before the
         *     eye opens or after it closes (the latter is the problem
         *     illustrated in the above figure).
         */

        /* Jam a negative ideal sample delay to zero. */
        if (ideal_sample_delay_in_ns < 0)
                ideal_sample_delay_in_ns = 0;

        /*
         * Extend the data setup as needed to reduce the ideal sample delay
         * below the maximum permitted by the NFC.
         */
        while ((ideal_sample_delay_in_ns > max_sample_delay_in_ns) &&
                        (data_setup_in_cycles < nfc->max_data_setup_cycles)) {

                /* Give a cycle to data setup. */
                data_setup_in_cycles++;
                /* Synchronize the data setup time with the cycles. */
                data_setup_in_ns += clock_period_in_ns;
                /* Adjust tEYE accordingly. */
                tEYE += clock_period_in_ns;

                /*
                 * Decrease the ideal sample delay by one half cycle, to keep it
                 * in the middle of the eye.
                 */
                ideal_sample_delay_in_ns -= (clock_period_in_ns >> 1);

                /* Jam a negative ideal sample delay to zero. */
                if (ideal_sample_delay_in_ns < 0)
                        ideal_sample_delay_in_ns = 0;
        }

        /*
         * Compute the sample delay factor that corresponds to the ideal sample
         * delay. If the result is too large, then use the maximum allowed
         * value.
         *
         * Notice that we use the ns_to_cycles function to compute the sample
         * delay factor. We do this because the form of the computation is the
         * same as that for calculating cycles.
         */
        sample_delay_factor =
                ns_to_cycles(ideal_sample_delay_in_ns << dll_delay_shift,
                                                        clock_period_in_ns, 0);

        if (sample_delay_factor > nfc->max_sample_delay_factor)
                sample_delay_factor = nfc->max_sample_delay_factor;

        /*
         * These macros conveniently encapsulate a computation we'll use to
         * continuously evaluate whether or not the data sample delay is inside
         * the eye.
         */
        #define IDEAL_DELAY  ((int) ideal_sample_delay_in_ns)

        #define QUANTIZED_DELAY  \
                ((int) ((sample_delay_factor * clock_period_in_ns) >> \
                                                        dll_delay_shift))

        #define DELAY_ERROR  (abs(QUANTIZED_DELAY - IDEAL_DELAY))

        #define SAMPLE_IS_NOT_WITHIN_THE_EYE  (DELAY_ERROR > (tEYE >> 1))

        /*
         * While the quantized sample time falls outside the eye, reduce the
         * sample delay or extend the data setup to move the sampling point back
         * toward the eye. Do not allow the number of data setup cycles to
         * exceed the maximum allowed by the NFC.
         */
        while (SAMPLE_IS_NOT_WITHIN_THE_EYE &&
                        (data_setup_in_cycles < nfc->max_data_setup_cycles)) {
                /*
                 * If control arrives here, the quantized sample delay falls
                 * outside the eye. Check if it's before the eye opens, or after
                 * the eye closes.
                 */
                if (QUANTIZED_DELAY > IDEAL_DELAY) {
                        /*
                         * If control arrives here, the quantized sample delay
                         * falls after the eye closes. Decrease the quantized
                         * delay time and then go back to re-evaluate.
                         */
                        if (sample_delay_factor != 0)
                                sample_delay_factor--;
                        continue;
                }

                /*
                 * If control arrives here, the quantized sample delay falls
                 * before the eye opens. Shift the sample point by increasing
                 * data setup time. This will also make the eye larger.
                 */

                /* Give a cycle to data setup. */
                data_setup_in_cycles++;
                /* Synchronize the data setup time with the cycles. */
                data_setup_in_ns += clock_period_in_ns;
                /* Adjust tEYE accordingly. */
                tEYE += clock_period_in_ns;

                /*
                 * Decrease the ideal sample delay by one half cycle, to keep it
                 * in the middle of the eye.
                 */
                ideal_sample_delay_in_ns -= (clock_period_in_ns >> 1);

                /* ...and one less period for the delay time. */
                ideal_sample_delay_in_ns -= clock_period_in_ns;

                /* Jam a negative ideal sample delay to zero. */
                if (ideal_sample_delay_in_ns < 0)
                        ideal_sample_delay_in_ns = 0;

                /*
                 * We have a new ideal sample delay, so re-compute the quantized
                 * delay.
                 */
                sample_delay_factor =
                        ns_to_cycles(
                                ideal_sample_delay_in_ns << dll_delay_shift,
                                                        clock_period_in_ns, 0);

                if (sample_delay_factor > nfc->max_sample_delay_factor)
                        sample_delay_factor = nfc->max_sample_delay_factor;
        }

        /* Control arrives here when we're ready to return our results. */
return_results:
        hw->data_setup_in_cycles    = data_setup_in_cycles;
        hw->data_hold_in_cycles     = data_hold_in_cycles;
        hw->address_setup_in_cycles = address_setup_in_cycles;
        hw->use_half_periods        = dll_use_half_periods;
        hw->sample_delay_factor     = sample_delay_factor;

        /* Return success. */
        return 0;
}

static int __devinit acquire_register_block(struct gpmi_nfc_data *this,
                        const char *resource_name, void **reg_block_base)
{
        struct platform_device *pdev = this->pdev;
        struct resource *r;
        void *p;

        r = platform_get_resource_byname(pdev, IORESOURCE_MEM, resource_name);
        if (!r) {
                pr_info("Can't get resource for %s\n", resource_name);
                return -ENXIO;
        }

        /* remap the register block */
        p = ioremap(r->start, resource_size(r));
        if (!p) {
                pr_info("Can't remap %s\n", resource_name);
                return -ENOMEM;
        }

        *reg_block_base = p;
        return 0;
}

static void release_register_block(struct gpmi_nfc_data *this,
                                void *reg_block_base)
{
        iounmap(reg_block_base);
}

static int __devinit acquire_interrupt(struct gpmi_nfc_data *this,
                        const char *resource_name,
                        irq_handler_t interrupt_handler, int *lno, int *hno)
{
        struct platform_device *pdev = this->pdev;
        struct resource *r;
        int err;

        r = platform_get_resource_byname(pdev, IORESOURCE_IRQ, resource_name);
        if (!r) {
                pr_info("Can't get resource for %s\n", resource_name);
                return -ENXIO;
        }

        BUG_ON(r->start != r->end);
        err = request_irq(r->start, interrupt_handler, 0, resource_name, this);
        if (err) {
                pr_info("Can't own %s\n", resource_name);
                return err;
        }

        *lno = r->start;
        *hno = r->end;
        return 0;
}

static void release_interrupt(struct gpmi_nfc_data *this,
                        int low_interrupt_number, int high_interrupt_number)
{
        int i;
        for (i = low_interrupt_number; i <= high_interrupt_number; i++)
                free_irq(i, this);
}

static bool gpmi_dma_filter(struct dma_chan *chan, void *param)
{
        struct gpmi_nfc_data *this = param;
        struct resource *r = this->private;

        if (!mxs_dma_is_apbh(chan))
                return false;
        /*
         * only catch the GPMI dma channels :
         *      for mx23 :      MX23_DMA_GPMI0 ~ MX23_DMA_GPMI3
         *              (These four channels share the same IRQ!)
         *
         *      for mx28 :      MX28_DMA_GPMI0 ~ MX28_DMA_GPMI7
         *              (These eight channels share the same IRQ!)
         */
        if (r->start <= chan->chan_id && chan->chan_id <= r->end) {
                chan->private = &this->dma_data;
                return true;
        }
        return false;
}

static void release_dma_channels(struct gpmi_nfc_data *this)
{
        unsigned int i;
        for (i = 0; i < DMA_CHANS; i++)
                if (this->dma_chans[i]) {
                        dma_release_channel(this->dma_chans[i]);
                        this->dma_chans[i] = NULL;
                }
}

static int __devinit acquire_dma_channels(struct gpmi_nfc_data *this,
                                const char *resource_name,
                                unsigned *low_channel, unsigned *high_channel)
{
        struct platform_device *pdev = this->pdev;
        struct gpmi_nfc_platform_data *pdata = this->pdata;
        struct resource *r, *r_dma;
        unsigned int i;

        r = platform_get_resource_byname(pdev, IORESOURCE_DMA, resource_name);
        r_dma = platform_get_resource_byname(pdev, IORESOURCE_IRQ,
                                        GPMI_NFC_DMA_INTERRUPT_RES_NAME);
        if (!r || !r_dma) {
                pr_info("Can't get resource for DMA\n");
                return -ENXIO;
        }

        /* used in gpmi_dma_filter() */
        this->private = r;

        for (i = r->start; i <= r->end; i++) {
                dma_cap_mask_t          mask;
                struct dma_chan         *dma_chan;

                if (i - r->start >= pdata->max_chip_count)
                        break;

                dma_cap_zero(mask);
                dma_cap_set(DMA_SLAVE, mask);

                /* get the DMA interrupt */
                this->dma_data.chan_irq = r_dma->start +
                        ((r_dma->start != r_dma->end) ? (i - r->start) : 0);

                dma_chan = dma_request_channel(mask, gpmi_dma_filter, this);
                if (!dma_chan)
                        goto acquire_err;
                /* fill the first empty item */
                this->dma_chans[i - r->start] = dma_chan;
        }

        *low_channel  = r->start;
        *high_channel = i;
        return 0;

acquire_err:
        pr_info("Can't acquire DMA channel %u\n", i);
        release_dma_channels(this);
        return -EINVAL;
}

static int __devinit acquire_resources(struct gpmi_nfc_data *this)
{
        struct resources *resources = &this->resources;
        int error;

        /* Attempt to acquire the GPMI register block. */
        error = acquire_register_block(this,
                                GPMI_NFC_GPMI_REGS_ADDR_RES_NAME,
                                &resources->gpmi_regs);
        if (error)
                goto exit_gpmi_regs;

        /* Attempt to acquire the BCH register block. */
        error = acquire_register_block(this,
                                GPMI_NFC_BCH_REGS_ADDR_RES_NAME,
                                &resources->bch_regs);
        if (error)
                goto exit_bch_regs;

        /* Attempt to acquire the BCH interrupt. */
        error = acquire_interrupt(this,
                                GPMI_NFC_BCH_INTERRUPT_RES_NAME,
                                bch_irq,
                                &resources->bch_low_interrupt,
                                &resources->bch_high_interrupt);
        if (error)
                goto exit_bch_interrupt;

        /* Attempt to acquire the DMA channels. */
        error = acquire_dma_channels(this,
                                GPMI_NFC_DMA_CHANNELS_RES_NAME,
                                &resources->dma_low_channel,
                                &resources->dma_high_channel);
        if (error)
                goto exit_dma_channels;

        /* Attempt to acquire our clock. */
        resources->clock = clk_get(&this->pdev->dev, NULL);
        if (IS_ERR(resources->clock)) {
                error = -ENOENT;
                pr_info("can not get the clock\n");
                goto exit_clock;
        }
        return 0;

exit_clock:
        release_dma_channels(this);
exit_dma_channels:
        release_interrupt(this, resources->bch_low_interrupt,
                                resources->bch_high_interrupt);
exit_bch_interrupt:
        release_register_block(this, resources->bch_regs);
exit_bch_regs:
        release_register_block(this, resources->gpmi_regs);
exit_gpmi_regs:
        return error;
}

static void release_resources(struct gpmi_nfc_data *this)
{
        struct resources  *resources = &this->resources;

        clk_put(resources->clock);
        release_register_block(this, resources->gpmi_regs);
        release_register_block(this, resources->bch_regs);
        release_interrupt(this, resources->bch_low_interrupt,
                                resources->bch_low_interrupt);
        release_dma_channels(this);
}

static void exit_nfc_hal(struct gpmi_nfc_data *this)
{
        if (this->nfc)
                this->nfc->exit(this);
}

static int __devinit set_up_nfc_hal(struct gpmi_nfc_data *this)
{
        struct nfc_hal *nfc = NULL;
        int error;

        /*
         * This structure contains the "safe" GPMI timing that should succeed
         * with any NAND Flash device
         * (although, with less-than-optimal performance).
         */
        static struct nand_timing  safe_timing = {
                .data_setup_in_ns        = 80,
                .data_hold_in_ns         = 60,
                .address_setup_in_ns     = 25,
                .gpmi_sample_delay_in_ns =  6,
                .tREA_in_ns              = -1,
                .tRLOH_in_ns             = -1,
                .tRHOH_in_ns             = -1,
        };

#if defined(CONFIG_SOC_IMX23) || defined(CONFIG_SOC_IMX28)
        if (GPMI_IS_MX23(this) || GPMI_IS_MX28(this))
                nfc = &gpmi_nfc_hal_imx23_imx28;
#endif
#if defined(CONFIG_SOC_IMX50)
        if (GPMI_IS_MX50(this))
                nfc = &gpmi_nfc_hal_mx50;
#endif
        BUG_ON(nfc == NULL);
        this->nfc = nfc;

        /* Initialize the NFC HAL. */
        error = nfc->init(this);
        if (error)
                return error;

        /* Set up safe timing. */
        nfc->set_timing(this, &safe_timing);
        return 0;
}

/* Creates/Removes sysfs files for this device.*/
static void manage_sysfs_files(struct gpmi_nfc_data *this, int create)
{
        struct device *dev = this->dev;
        struct device_attribute **attr;
        unsigned int i;
        int error;

        for (i = 0, attr = device_attributes;
                        i < ARRAY_SIZE(device_attributes); i++, attr++) {

                if (create) {
                        error = device_create_file(dev, *attr);
                        if (error) {
                                while (--attr >= device_attributes)
                                        device_remove_file(dev, *attr);
                                return;
                        }
                } else {
                        device_remove_file(dev, *attr);
                }
        }
}

static int read_page_prepare(struct gpmi_nfc_data *this,
                        void *destination, unsigned length,
                        void *alt_virt, dma_addr_t alt_phys, unsigned alt_size,
                        void **use_virt, dma_addr_t *use_phys)
{
        struct device  *dev = this->dev;
        dma_addr_t destination_phys = ~0;

        if (virt_addr_valid(destination))
                destination_phys = dma_map_single(dev, destination,
                                                length, DMA_FROM_DEVICE);

        if (dma_mapping_error(dev, destination_phys)) {
                if (alt_size < length) {
                        pr_info("Alternate buffer is too small\n");
                        return -ENOMEM;
                }

                *use_virt = alt_virt;
                *use_phys = alt_phys;
                this->mil.direct_dma_map_ok = false;
        } else {
                *use_virt = destination;
                *use_phys = destination_phys;
                this->mil.direct_dma_map_ok = true;
        }
        return 0;
}

static void read_page_end(struct gpmi_nfc_data *this,
                        void *destination, unsigned length,
                        void *alt_virt, dma_addr_t alt_phys, unsigned alt_size,
                        void *used_virt, dma_addr_t used_phys)
{
        if (this->mil.direct_dma_map_ok)
                dma_unmap_single(this->dev, used_phys, length, DMA_FROM_DEVICE);
}

static void read_page_swap_end(struct gpmi_nfc_data *this,
                        void *destination, unsigned length,
                        void *alt_virt, dma_addr_t alt_phys, unsigned alt_size,
                        void *used_virt, dma_addr_t used_phys)
{
        struct device *dev = this->dev;

        if (!this->mil.direct_dma_map_ok)
                memcpy(destination, alt_virt, length);
}

static int send_page_prepare(struct gpmi_nfc_data *this,
                        const void *source, unsigned length,
                        void *alt_virt, dma_addr_t alt_phys, unsigned alt_size,
                        const void **use_virt, dma_addr_t *use_phys)
{
        dma_addr_t source_phys = ~0;
        struct device *dev = this->dev;

        if (virt_addr_valid(source))
                source_phys = dma_map_single(dev,
                                (void *)source, length, DMA_TO_DEVICE);

        if (dma_mapping_error(dev, source_phys)) {
                if (alt_size < length) {
                        pr_info("Alternate buffer is too small\n");
                        return -ENOMEM;
                }

                /*
                 * Copy the contents of the source buffer into the alternate
                 * buffer and set up the return values accordingly.
                 */
                memcpy(alt_virt, source, length);

                *use_virt = alt_virt;
                *use_phys = alt_phys;
        } else {
                *use_virt = source;
                *use_phys = source_phys;
        }
        return 0;
}

static void send_page_end(struct gpmi_nfc_data *this,
                        const void *source, unsigned length,
                        void *alt_virt, dma_addr_t alt_phys, unsigned alt_size,
                        const void *used_virt, dma_addr_t used_phys)
{
        struct device *dev = this->dev;
        if (used_virt == source)
                dma_unmap_single(dev, used_phys, length, DMA_TO_DEVICE);
}

static void mil_free_dma_buffer(struct gpmi_nfc_data *this)
{
        struct device *dev = this->dev;
        struct mil *mil = &this->mil;

        if (mil->page_buffer_virt && virt_addr_valid(mil->page_buffer_virt))
                dma_free_coherent(dev, mil->page_buffer_size,
                                        mil->page_buffer_virt,
                                        mil->page_buffer_phys);
        kfree(mil->cmd_buffer);
        kfree(mil->data_buffer_dma);

        mil->cmd_buffer         = NULL;
        mil->data_buffer_dma    = NULL;
        mil->page_buffer_virt   = NULL;
        mil->page_buffer_size   =  0;
        mil->page_buffer_phys   = ~0;
}

/* Allocate the DMA buffers */
static int mil_alloc_dma_buffer(struct gpmi_nfc_data *this)
{
        struct nfc_geometry *geo = &this->nfc_geometry;
        struct device *dev = this->dev;
        struct mil *mil = &this->mil;

        /* [1] Allocate a command buffer. PAGE_SIZE is enough. */
        mil->cmd_buffer = kzalloc(PAGE_SIZE, GFP_DMA);
        if (mil->cmd_buffer == NULL)
                goto error_alloc;

        /* [2] Allocate a read/write data buffer. PAGE_SIZE is enough. */
        mil->data_buffer_dma = kzalloc(PAGE_SIZE, GFP_DMA);
        if (mil->data_buffer_dma == NULL)
                goto error_alloc;

        /*
         * [3] Allocate the page buffer.
         *
         * Both the payload buffer and the auxiliary buffer must appear on
         * 32-bit boundaries. We presume the size of the payload buffer is a
         * power of two and is much larger than four, which guarantees the
         * auxiliary buffer will appear on a 32-bit boundary.
         */
        mil->page_buffer_size = geo->payload_size_in_bytes +
                                geo->auxiliary_size_in_bytes;

        mil->page_buffer_virt = dma_alloc_coherent(dev, mil->page_buffer_size,
                                        &mil->page_buffer_phys, GFP_DMA);
        if (!mil->page_buffer_virt)
                goto error_alloc;


        /* Slice up the page buffer. */
        mil->payload_virt = mil->page_buffer_virt;
        mil->payload_phys = mil->page_buffer_phys;
        mil->auxiliary_virt = mil->payload_virt + geo->payload_size_in_bytes;
        mil->auxiliary_phys = mil->payload_phys + geo->payload_size_in_bytes;
        return 0;

error_alloc:
        mil_free_dma_buffer(this);
        pr_info("allocate DMA buffer error!!\n");
        return -ENOMEM;
}

static void mil_cmd_ctrl(struct mtd_info *mtd, int data, unsigned int ctrl)
{
        struct nand_chip *nand = mtd->priv;
        struct gpmi_nfc_data *this = nand->priv;
        struct mil *mil = &this->mil;
        struct nfc_hal *nfc = this->nfc;
        int error;

        /*
         * Every operation begins with a command byte and a series of zero or
         * more address bytes. These are distinguished by either the Address
         * Latch Enable (ALE) or Command Latch Enable (CLE) signals being
         * asserted. When MTD is ready to execute the command, it will deassert
         * both latch enables.
         *
         * Rather than run a separate DMA operation for every single byte, we
         * queue them up and run a single DMA operation for the entire series
         * of command and data bytes. NAND_CMD_NONE means the END of the queue.
         */
        if ((ctrl & (NAND_ALE | NAND_CLE))) {
                if (data != NAND_CMD_NONE)
                        mil->cmd_buffer[mil->command_length++] = data;
                return;
        }

        if (!mil->command_length)
                return;

        error = nfc->send_command(this);
        if (error)
                pr_info("Chip: %u, Error %d\n", mil->current_chip, error);

        mil->command_length = 0;
}

static int mil_dev_ready(struct mtd_info *mtd)
{
        struct nand_chip *nand = mtd->priv;
        struct gpmi_nfc_data *this = nand->priv;
        struct nfc_hal *nfc = this->nfc;
        struct mil *mil = &this->mil;

        return nfc->is_ready(this, mil->current_chip);
}

static void mil_select_chip(struct mtd_info *mtd, int chip)
{
        struct nand_chip *nand = mtd->priv;
        struct gpmi_nfc_data *this = nand->priv;
        struct nfc_hal *nfc = this->nfc;
        struct mil *mil = &this->mil;

        if ((mil->current_chip < 0) && (chip >= 0))
                nfc->begin(this);
        else if ((mil->current_chip >= 0) && (chip < 0))
                nfc->end(this);
        else
                ;

        mil->current_chip = chip;
}

static void mil_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
{
        struct nand_chip *nand = mtd->priv;
        struct gpmi_nfc_data *this = nand->priv;
        struct nfc_hal *nfc = this->nfc;
        struct mil *mil = &this->mil;

        logio(GPMI_DEBUG_READ);
        /* save the info in mil{} for future */
        mil->upper_buf  = buf;
        mil->upper_len  = len;

        nfc->read_data(this);
}

static void mil_write_buf(struct mtd_info *mtd, const uint8_t *buf, int len)
{
        struct nand_chip *nand = mtd->priv;
        struct gpmi_nfc_data *this = nand->priv;
        struct nfc_hal *nfc = this->nfc;
        struct mil *mil = &this->mil;

        logio(GPMI_DEBUG_WRITE);
        /* save the info in mil{} for future */
        mil->upper_buf  = (uint8_t *)buf;
        mil->upper_len  = len;

        nfc->send_data(this);
}

static uint8_t mil_read_byte(struct mtd_info *mtd)
{
        struct nand_chip *nand = mtd->priv;
        struct gpmi_nfc_data *this = nand->priv;
        struct mil *mil = &this->mil;
        uint8_t *buf = mil->data_buffer_dma;

        mil_read_buf(mtd, buf, 1);
        return buf[0];
}

/**
 * mil_handle_block_mark_swapping() - Handles block mark swapping.
 *
 * Note that, when this function is called, it doesn't know whether it's
 * swapping the block mark, or swapping it *back* -- but it doesn't matter
 * because the the operation is the same.
 *
 * @this:       Per-device data.
 * @payload:    A pointer to the payload buffer.
 * @auxiliary:  A pointer to the auxiliary buffer.
 */
static void mil_handle_block_mark_swapping(struct gpmi_nfc_data *this,
                                                void *payload, void *auxiliary)
{
        struct nfc_geometry *nfc_geo = &this->nfc_geometry;
        unsigned char *p;
        unsigned char *a;
        unsigned int  bit;
        unsigned char mask;
        unsigned char from_data;
        unsigned char from_oob;

        /* Check if we're doing block mark swapping. */
        if (!this->swap_block_mark)
                return;

        /*
         * If control arrives here, we're swapping. Make some convenience
         * variables.
         */
        bit = nfc_geo->block_mark_bit_offset;
        p   = payload + nfc_geo->block_mark_byte_offset;
        a   = auxiliary;

        /*
         * Get the byte from the data area that overlays the block mark. Since
         * the ECC engine applies its own view to the bits in the page, the
         * physical block mark won't (in general) appear on a byte boundary in
         * the data.
         */
        from_data = (p[0] >> bit) | (p[1] << (8 - bit));

        /* Get the byte from the OOB. */
        from_oob = a[0];

        /* Swap them. */
        a[0] = from_data;

        mask = (0x1 << bit) - 1;
        p[0] = (p[0] & mask) | (from_oob << bit);

        mask = ~0 << bit;
        p[1] = (p[1] & mask) | (from_oob >> (8 - bit));
}

static int mil_ecc_read_page(struct mtd_info *mtd, struct nand_chip *nand,
                                uint8_t *buf, int page)
{
        struct gpmi_nfc_data *this = nand->priv;
        struct nfc_hal *nfc = this->nfc;
        struct nfc_geometry *nfc_geo = &this->nfc_geometry;
        struct mil *mil = &this->mil;
        void          *payload_virt;
        dma_addr_t    payload_phys;
        void          *auxiliary_virt;
        dma_addr_t    auxiliary_phys;
        unsigned int  i;
        unsigned char *status;
        unsigned int  failed;
        unsigned int  corrected;
        int           error;

        logio(GPMI_DEBUG_ECC_READ);
        error = read_page_prepare(this, buf, mtd->writesize,
                                        mil->payload_virt, mil->payload_phys,
                                        nfc_geo->payload_size_in_bytes,
                                        &payload_virt, &payload_phys);
        if (error) {
                pr_info("Inadequate DMA buffer\n");
                error = -ENOMEM;
                return error;
        }
        auxiliary_virt = mil->auxiliary_virt;
        auxiliary_phys = mil->auxiliary_phys;

        /* ask the NFC */
        error = nfc->read_page(this, payload_phys, auxiliary_phys);
        read_page_end(this, buf, mtd->writesize,
                        mil->payload_virt, mil->payload_phys,
                        nfc_geo->payload_size_in_bytes,
                        payload_virt, payload_phys);
        if (error) {
                pr_info("Error in ECC-based read: %d\n", error);
                goto exit_nfc;
        }

        /* handle the block mark swapping */
        mil_handle_block_mark_swapping(this, payload_virt, auxiliary_virt);

        /* Loop over status bytes, accumulating ECC status. */
        failed          = 0;
        corrected       = 0;
        status          = auxiliary_virt + nfc_geo->auxiliary_status_offset;

        for (i = 0; i < nfc_geo->ecc_chunk_count; i++, status++) {
                if ((*status == STATUS_GOOD) || (*status == STATUS_ERASED))
                        continue;

                if (*status == STATUS_UNCORRECTABLE) {
                        failed++;
                        continue;
                }
                corrected += *status;
        }

        /*
         * Propagate ECC status to the owning MTD only when failed or
         * corrected times nearly reaches our ECC correction threshold.
         */
        if (failed || corrected >= (nfc_geo->ecc_strength - 1)) {
                mtd->ecc_stats.failed    += failed;
                mtd->ecc_stats.corrected += corrected;
        }

        /*
         * It's time to deliver the OOB bytes. See mil_ecc_read_oob() for
         * details about our policy for delivering the OOB.
         *
         * We fill the caller's buffer with set bits, and then copy the block
         * mark to th caller's buffer. Note that, if block mark swapping was
         * necessary, it has already been done, so we can rely on the first
         * byte of the auxiliary buffer to contain the block mark.
         */
        memset(nand->oob_poi, ~0, mtd->oobsize);
        nand->oob_poi[0] = ((uint8_t *) auxiliary_virt)[0];

        read_page_swap_end(this, buf, mtd->writesize,
                        mil->payload_virt, mil->payload_phys,
                        nfc_geo->payload_size_in_bytes,
                        payload_virt, payload_phys);
exit_nfc:
        return error;
}

static void mil_ecc_write_page(struct mtd_info *mtd,
                                struct nand_chip *nand, const uint8_t *buf)
{
        struct gpmi_nfc_data *this = nand->priv;
        struct nfc_hal *nfc =  this->nfc;
        struct nfc_geometry *nfc_geo = &this->nfc_geometry;
        struct mil *mil = &this->mil;
        const void *payload_virt;
        dma_addr_t payload_phys;
        const void *auxiliary_virt;
        dma_addr_t auxiliary_phys;
        int        error;

        logio(GPMI_DEBUG_ECC_WRITE);
        if (this->swap_block_mark) {
                /*
                 * If control arrives here, we're doing block mark swapping.
                 * Since we can't modify the caller's buffers, we must copy them
                 * into our own.
                 */
                memcpy(mil->payload_virt, buf, mtd->writesize);
                payload_virt = mil->payload_virt;
                payload_phys = mil->payload_phys;

                memcpy(mil->auxiliary_virt, nand->oob_poi,
                                nfc_geo->auxiliary_size_in_bytes);
                auxiliary_virt = mil->auxiliary_virt;
                auxiliary_phys = mil->auxiliary_phys;

                /* Handle block mark swapping. */
                mil_handle_block_mark_swapping(this,
                                (void *) payload_virt, (void *) auxiliary_virt);
        } else {
                /*
                 * If control arrives here, we're not doing block mark swapping,
                 * so we can to try and use the caller's buffers.
                 */
                error = send_page_prepare(this,
                                buf, mtd->writesize,
                                mil->payload_virt, mil->payload_phys,
                                nfc_geo->payload_size_in_bytes,
                                &payload_virt, &payload_phys);
                if (error) {
                        pr_info("Inadequate payload DMA buffer\n");
                        return;
                }

                error = send_page_prepare(this,
                                nand->oob_poi, mtd->oobsize,
                                mil->auxiliary_virt, mil->auxiliary_phys,
                                nfc_geo->auxiliary_size_in_bytes,
                                &auxiliary_virt, &auxiliary_phys);
                if (error) {
                        pr_info("Inadequate auxiliary DMA buffer\n");
                        goto exit_auxiliary;
                }
        }

        /* Ask the NFC. */
        error = nfc->send_page(this, payload_phys, auxiliary_phys);
        if (error)
                pr_info("Error in ECC-based write: %d\n", error);

        if (!this->swap_block_mark) {
                send_page_end(this, nand->oob_poi, mtd->oobsize,
                                mil->auxiliary_virt, mil->auxiliary_phys,
                                nfc_geo->auxiliary_size_in_bytes,
                                auxiliary_virt, auxiliary_phys);
exit_auxiliary:
                send_page_end(this, buf, mtd->writesize,
                                mil->payload_virt, mil->payload_phys,
                                nfc_geo->payload_size_in_bytes,
                                payload_virt, payload_phys);
        }
}

static int mil_hook_block_markbad(struct mtd_info *mtd, loff_t ofs)
{
        register struct nand_chip *chip = mtd->priv;
        struct gpmi_nfc_data *this = chip->priv;
        struct mil *mil = &this->mil;
        int ret;

        mil->marking_a_bad_block = true;
        ret = mil->hooked_block_markbad(mtd, ofs);
        mil->marking_a_bad_block = false;
        return ret;
}

/**
 * mil_ecc_read_oob() - MTD Interface ecc.read_oob().
 *
 * There are several places in this driver where we have to handle the OOB and
 * block marks. This is the function where things are the most complicated, so
 * this is where we try to explain it all. All the other places refer back to
 * here.
 *
 * These are the rules, in order of decreasing importance:
 *
 * 1) Nothing the caller does can be allowed to imperil the block mark, so all
 *    write operations take measures to protect it.
 *
 * 2) In read operations, the first byte of the OOB we return must reflect the
 *    true state of the block mark, no matter where that block mark appears in
 *    the physical page.
 *
 * 3) ECC-based read operations return an OOB full of set bits (since we never
 *    allow ECC-based writes to the OOB, it doesn't matter what ECC-based reads
 *    return).
 *
 * 4) "Raw" read operations return a direct view of the physical bytes in the
 *    page, using the conventional definition of which bytes are data and which
 *    are OOB. This gives the caller a way to see the actual, physical bytes
 *    in the page, without the distortions applied by our ECC engine.
 *
 *
 * What we do for this specific read operation depends on two questions:
 *
 * 1) Are we doing a "raw" read, or an ECC-based read?
 *
 * 2) Are we using block mark swapping or transcription?
 *
 * There are four cases, illustrated by the following Karnaugh map:
 *
 *                    |           Raw           |         ECC-based       |
 *       -------------+-------------------------+-------------------------+
 *                    | Read the conventional   |                         |
 *                    | OOB at the end of the   |                         |
 *       Swapping     | page and return it. It  |                         |
 *                    | contains exactly what   |                         |
 *                    | we want.                | Read the block mark and |
 *       -------------+-------------------------+ return it in a buffer   |
 *                    | Read the conventional   | full of set bits.       |
 *                    | OOB at the end of the   |                         |
 *                    | page and also the block |                         |
 *       Transcribing | mark in the metadata.   |                         |
 *                    | Copy the block mark     |                         |
 *                    | into the first byte of  |                         |
 *                    | the OOB.                |                         |
 *       -------------+-------------------------+-------------------------+
 *
 * Note that we break rule #4 in the Transcribing/Raw case because we're not
 * giving an accurate view of the actual, physical bytes in the page (we're
 * overwriting the block mark). That's OK because it's more important to follow
 * rule #2.
 *
 * It turns out that knowing whether we want an "ECC-based" or "raw" read is not
 * easy. When reading a page, for example, the NAND Flash MTD code calls our
 * ecc.read_page or ecc.read_page_raw function. Thus, the fact that MTD wants an
 * ECC-based or raw view of the page is implicit in which function it calls
 * (there is a similar pair of ECC-based/raw functions for writing).
 *
 * Since MTD assumes the OOB is not covered by ECC, there is no pair of
 * ECC-based/raw functions for reading or or writing the OOB. The fact that the
 * caller wants an ECC-based or raw view of the page is not propagated down to
 * this driver.
 *
 * @mtd:     A pointer to the owning MTD.
 * @nand:    A pointer to the owning NAND Flash MTD.
 * @page:    The page number to read.
 * @sndcmd:  Indicates this function should send a command to the chip before
 *           reading the out-of-band bytes. This is only false for small page
 *           chips that support auto-increment.
 */
static int mil_ecc_read_oob(struct mtd_info *mtd, struct nand_chip *nand,
                                                        int page, int sndcmd)
{
        struct gpmi_nfc_data *this = nand->priv;

        /* clear the OOB buffer */
        memset(nand->oob_poi, ~0, mtd->oobsize);

        /* Read out the conventional OOB. */
        nand->cmdfunc(mtd, NAND_CMD_READ0, mtd->writesize, page);
        nand->read_buf(mtd, nand->oob_poi, mtd->oobsize);

        /*
         * Now, we want to make sure the block mark is correct. In the
         * Swapping/Raw case, we already have it. Otherwise, we need to
         * explicitly read it.
         */
        if (!this->swap_block_mark) {
                /* Read the block mark into the first byte of the OOB buffer. */
                nand->cmdfunc(mtd, NAND_CMD_READ0, 0, page);
                nand->oob_poi[0] = nand->read_byte(mtd);
        }

        /*
         * Return true, indicating that the next call to this function must send
         * a command.
         */
        return true;
}

static int mil_ecc_write_oob(struct mtd_info *mtd,
                                struct nand_chip *nand, int page)
{
        struct gpmi_nfc_data *this = nand->priv;
        struct device *dev = this->dev;
        struct mil *mil = &this->mil;
        uint8_t *block_mark;
        int block_mark_column;
        int status;
        int error = 0;

        /* Only marking a block bad is permitted to write the OOB. */
        if (!mil->marking_a_bad_block) {
                dev_emerg(dev, "This driver doesn't support writing the OOB\n");
                WARN_ON(1);
                error = -EIO;
                goto exit;
        }

        if (this->swap_block_mark)
                block_mark_column = mtd->writesize;
        else
                block_mark_column = 0;

        /* Write the block mark. */
        block_mark = mil->data_buffer_dma;
        block_mark[0] = 0; /* bad block marker */

        nand->cmdfunc(mtd, NAND_CMD_SEQIN, block_mark_column, page);
        nand->write_buf(mtd, block_mark, 1);
        nand->cmdfunc(mtd, NAND_CMD_PAGEPROG, -1, -1);

        status = nand->waitfunc(mtd, nand);

        /* Check if it worked. */
        if (status & NAND_STATUS_FAIL)
                error = -EIO;
exit:
        return error;
}

/**
 * mil_block_bad - Claims all blocks are good.
 *
 * In principle, this function is *only* called when the NAND Flash MTD system
 * isn't allowed to keep an in-memory bad block table, so it is forced to ask
 * the driver for bad block information.
 *
 * In fact, we permit the NAND Flash MTD system to have an in-memory BBT, so
 * this function is *only* called when we take it away.
 *
 * We take away the in-memory BBT when the user sets the "ignorebad" parameter,
 * which indicates that all blocks should be reported good.
 *
 * Thus, this function is only called when we want *all* blocks to look good,
 * so it *always* return success.
 *
 * @mtd:      Ignored.
 * @ofs:      Ignored.
 * @getchip:  Ignored.
 */
static int mil_block_bad(struct mtd_info *mtd, loff_t ofs, int getchip)
{
        return 0;
}

static int __devinit nand_boot_set_geometry(struct gpmi_nfc_data *this)
{
        struct boot_rom_geometry *geometry = &this->rom_geometry;

        /*
         * Set the boot block stride size.
         *
         * In principle, we should be reading this from the OTP bits, since
         * that's where the ROM is going to get it. In fact, we don't have any
         * way to read the OTP bits, so we go with the default and hope for the
         * best.
         */
        geometry->stride_size_in_pages = 64;

        /*
         * Set the search area stride exponent.
         *
         * In principle, we should be reading this from the OTP bits, since
         * that's where the ROM is going to get it. In fact, we don't have any
         * way to read the OTP bits, so we go with the default and hope for the
         * best.
         */
        geometry->search_area_stride_exponent = 2;

        if (gpmi_debug & GPMI_DEBUG_INIT)
                pr_info("stride size in page : %d, search areas : %d\n",
                        geometry->stride_size_in_pages,
                        geometry->search_area_stride_exponent);
        return 0;
}

static const char  *fingerprint = "STMP";
static int __devinit mx23_check_transcription_stamp(struct gpmi_nfc_data *this)
{
        struct boot_rom_geometry *rom_geo = &this->rom_geometry;
        struct mil *mil = &this->mil;
        struct mtd_info *mtd = &mil->mtd;
        struct nand_chip *nand = &mil->nand;
        unsigned int search_area_size_in_strides;
        unsigned int stride;
        unsigned int page;
        loff_t byte;
        uint8_t *buffer = nand->buffers->databuf;
        int saved_chip_number;
        int found_an_ncb_fingerprint = false;

        /* Compute the number of strides in a search area. */
        search_area_size_in_strides = 1 << rom_geo->search_area_stride_exponent;

        /* Select chip 0. */
        saved_chip_number = mil->current_chip;
        nand->select_chip(mtd, 0);

        /*
         * Loop through the first search area, looking for the NCB fingerprint.
         */
        pr_info("Scanning for an NCB fingerprint...\n");

        for (stride = 0; stride < search_area_size_in_strides; stride++) {
                /* Compute the page and byte addresses. */
                page = stride * rom_geo->stride_size_in_pages;
                byte = page   * mtd->writesize;

                pr_info("  Looking for a fingerprint in page 0x%x\n", page);

                /*
                 * Read the NCB fingerprint. The fingerprint is four bytes long
                 * and starts in the 12th byte of the page.
                 */
                nand->cmdfunc(mtd, NAND_CMD_READ0, 12, page);
                nand->read_buf(mtd, buffer, strlen(fingerprint));

                /* Look for the fingerprint. */
                if (!memcmp(buffer, fingerprint, strlen(fingerprint))) {
                        found_an_ncb_fingerprint = true;
                        break;
                }

        }

        /* Deselect chip 0. */
        nand->select_chip(mtd, saved_chip_number);

        if (found_an_ncb_fingerprint)
                pr_info("  Found a fingerprint\n");
        else
                pr_info("  No fingerprint found\n");
        return found_an_ncb_fingerprint;
}

/* Writes a transcription stamp. */
static int __devinit mx23_write_transcription_stamp(struct gpmi_nfc_data *this)
{
        struct device *dev = this->dev;
        struct boot_rom_geometry *rom_geo = &this->rom_geometry;
        struct mil *mil = &this->mil;
        struct mtd_info *mtd = &mil->mtd;
        struct nand_chip *nand = &mil->nand;
        unsigned int block_size_in_pages;
        unsigned int search_area_size_in_strides;
        unsigned int search_area_size_in_pages;
        unsigned int search_area_size_in_blocks;
        unsigned int block;
        unsigned int stride;
        unsigned int page;
        loff_t       byte;
        uint8_t      *buffer = nand->buffers->databuf;
        int saved_chip_number;
        int status;

        /* Compute the search area geometry. */
        block_size_in_pages = mtd->erasesize / mtd->writesize;
        search_area_size_in_strides = 1 << rom_geo->search_area_stride_exponent;
        search_area_size_in_pages = search_area_size_in_strides *
                                        rom_geo->stride_size_in_pages;
        search_area_size_in_blocks =
                  (search_area_size_in_pages + (block_size_in_pages - 1)) /
                                    block_size_in_pages;

        pr_info("-------------------------------------------\n");
        pr_info("Search Area Geometry\n");
        pr_info("-------------------------------------------\n");
        pr_info("Search Area in Blocks : %u\n", search_area_size_in_blocks);
        pr_info("Search Area in Strides: %u\n", search_area_size_in_strides);
        pr_info("Search Area in Pages  : %u\n", search_area_size_in_pages);

        /* Select chip 0. */
        saved_chip_number = mil->current_chip;
        nand->select_chip(mtd, 0);

        /* Loop over blocks in the first search area, erasing them. */
        pr_info("Erasing the search area...\n");

        for (block = 0; block < search_area_size_in_blocks; block++) {
                /* Compute the page address. */
                page = block * block_size_in_pages;

                /* Erase this block. */
                pr_info("  Erasing block 0x%x\n", block);
                nand->cmdfunc(mtd, NAND_CMD_ERASE1, -1, page);
                nand->cmdfunc(mtd, NAND_CMD_ERASE2, -1, -1);

                /* Wait for the erase to finish. */
                status = nand->waitfunc(mtd, nand);
                if (status & NAND_STATUS_FAIL)
                        dev_err(dev, "[%s] Erase failed.\n", __func__);
        }

        /* Write the NCB fingerprint into the page buffer. */
        memset(buffer, ~0, mtd->writesize);
        memset(nand->oob_poi, ~0, mtd->oobsize);
        memcpy(buffer + 12, fingerprint, strlen(fingerprint));

        /* Loop through the first search area, writing NCB fingerprints. */
        pr_info("Writing NCB fingerprints...\n");
        for (stride = 0; stride < search_area_size_in_strides; stride++) {
                /* Compute the page and byte addresses. */
                page = stride * rom_geo->stride_size_in_pages;
                byte = page   * mtd->writesize;

                /* Write the first page of the current stride. */
                pr_info("  Writing an NCB fingerprint in page 0x%x\n", page);
                nand->cmdfunc(mtd, NAND_CMD_SEQIN, 0x00, page);
                nand->ecc.write_page_raw(mtd, nand, buffer);
                nand->cmdfunc(mtd, NAND_CMD_PAGEPROG, -1, -1);

                /* Wait for the write to finish. */
                status = nand->waitfunc(mtd, nand);
                if (status & NAND_STATUS_FAIL)
                        dev_err(dev, "[%s] Write failed.\n", __func__);
        }

        /* Deselect chip 0. */
        nand->select_chip(mtd, saved_chip_number);
        return 0;
}

static int __devinit mx23_boot_init(struct gpmi_nfc_data  *this)
{
        struct device *dev = this->dev;
        struct mil *mil = &this->mil;
        struct nand_chip *nand = &mil->nand;
        struct mtd_info *mtd = &mil->mtd;
        unsigned int block_count;
        unsigned int block;
        int     chip;
        int     page;
        loff_t  byte;
        uint8_t block_mark;
        int     error = 0;

        /*
         * If control arrives here, we can't use block mark swapping, which
         * means we're forced to use transcription. First, scan for the
         * transcription stamp. If we find it, then we don't have to do
         * anything -- the block marks are already transcribed.
         */
        if (mx23_check_transcription_stamp(this))
                return 0;

        /*
         * If control arrives here, we couldn't find a transcription stamp, so
         * so we presume the block marks are in the conventional location.
         */
        pr_info("Transcribing bad block marks...\n");

        /* Compute the number of blocks in the entire medium. */
        block_count = nand->chipsize >> nand->phys_erase_shift;

        /*
         * Loop over all the blocks in the medium, transcribing block marks as
         * we go.
         */
        for (block = 0; block < block_count; block++) {
                /*
                 * Compute the chip, page and byte addresses for this block's
                 * conventional mark.
                 */
                chip = block >> (nand->chip_shift - nand->phys_erase_shift);
                page = block << (nand->phys_erase_shift - nand->page_shift);
                byte = block <<  nand->phys_erase_shift;

                /* Select the chip. */
                nand->select_chip(mtd, chip);

                /* Send the command to read the conventional block mark. */
                nand->cmdfunc(mtd, NAND_CMD_READ0, mtd->writesize, page);

                /* Read the conventional block mark. */
                block_mark = nand->read_byte(mtd);

                /*
                 * Check if the block is marked bad. If so, we need to mark it
                 * again, but this time the result will be a mark in the
                 * location where we transcribe block marks.
                 *
                 * Notice that we have to explicitly set the marking_a_bad_block
                 * member before we call through the block_markbad function
                 * pointer in the owning struct nand_chip. If we could call
                 * though the block_markbad function pointer in the owning
                 * struct mtd_info, which we have hooked, then this would be
                 * taken care of for us. Unfortunately, we can't because that
                 * higher-level code path will do things like consulting the
                 * in-memory bad block table -- which doesn't even exist yet!
                 * So, we have to call at a lower level and handle some details
                 * ourselves.
                 */
                if (block_mark != 0xff) {
                        pr_info("Transcribing mark in block %u\n", block);
                        mil->marking_a_bad_block = true;
                        error = nand->block_markbad(mtd, byte);
                        mil->marking_a_bad_block = false;
                        if (error)
                                dev_err(dev, "Failed to mark block bad with "
                                                        "error %d\n", error);
                }

                /* Deselect the chip. */
                nand->select_chip(mtd, -1);
        }

        /* Write the stamp that indicates we've transcribed the block marks. */
        mx23_write_transcription_stamp(this);
        return 0;
}

static int __devinit nand_boot_init(struct gpmi_nfc_data  *this)
{
        nand_boot_set_geometry(this);

        /* This is ROM arch-specific initilization before the BBT scanning. */
        if (GPMI_IS_MX23(this))
                return mx23_boot_init(this);
        return 0;
}

static void show_nfc_geometry(struct nfc_geometry *geo)
{
        pr_info("---------------------------------------\n");
        pr_info("       NFC Geometry (used by BCH)\n");
        pr_info("---------------------------------------\n");
        pr_info("ECC Algorithm          : %s\n", geo->ecc_algorithm);
        pr_info("ECC Strength           : %u\n", geo->ecc_strength);
        pr_info("Page Size in Bytes     : %u\n", geo->page_size_in_bytes);
        pr_info("Metadata Size in Bytes : %u\n", geo->metadata_size_in_bytes);
        pr_info("ECC Chunk Size in Bytes: %u\n", geo->ecc_chunk_size_in_bytes);
        pr_info("ECC Chunk Count        : %u\n", geo->ecc_chunk_count);
        pr_info("Payload Size in Bytes  : %u\n", geo->payload_size_in_bytes);
        pr_info("Auxiliary Size in Bytes: %u\n", geo->auxiliary_size_in_bytes);
        pr_info("Auxiliary Status Offset: %u\n", geo->auxiliary_status_offset);
        pr_info("Block Mark Byte Offset : %u\n", geo->block_mark_byte_offset);
        pr_info("Block Mark Bit Offset  : %u\n", geo->block_mark_bit_offset);
}

static int __devinit mil_set_geometry(struct gpmi_nfc_data *this)
{
        struct nfc_hal *nfc = this->nfc;
        struct nfc_geometry *geo = &this->nfc_geometry;
        int error;

        /* Free the temporary DMA memory for read ID case */
        mil_free_dma_buffer(this);

        /* Set up the NFC geometry which is used by BCH. */
        error = nfc->set_geometry(this);
        if (error != 0) {
                pr_info("NFC set geometry error : %d\n", error);
                return error;
        }
        if (gpmi_debug & GPMI_DEBUG_INIT)
                show_nfc_geometry(geo);

        /* Alloc the new DMA buffers according to the pagesize and oobsize */
        return mil_alloc_dma_buffer(this);
}

static int mil_pre_bbt_scan(struct gpmi_nfc_data  *this)
{
        struct nand_chip *nand = &this->mil.nand;
        struct mtd_info *mtd = &this->mil.mtd;
        struct nand_ecclayout *layout = nand->ecc.layout;
        struct nfc_hal *nfc = this->nfc;
        int error;

        /* fix the ECC layout before the scanning */
        layout->eccbytes          = 0;
        layout->oobavail          = mtd->oobsize;
        layout->oobfree[0].offset = 0;
        layout->oobfree[0].length = mtd->oobsize;

        mtd->oobavail = nand->ecc.layout->oobavail;

        /* Set up swap block-mark, must be set before the mil_set_geometry() */
        if (GPMI_IS_MX23(this))
                this->swap_block_mark = false;
        else
                this->swap_block_mark = true;

        /* Set up the medium geometry */
        error = mil_set_geometry(this);
        if (error)
                return error;

        /* extra init */
        if (nfc->extra_init) {
                error = nfc->extra_init(this);
                if (error != 0)
                        return error;
        }

        /* NAND boot init, depends on the mil_set_geometry(). */
        return nand_boot_init(this);
}

static int mil_scan_bbt(struct mtd_info *mtd)
{
        struct nand_chip *nand = mtd->priv;
        struct gpmi_nfc_data *this = nand->priv;
        int error;

        /* Prepare for the BBT scan. */
        error = mil_pre_bbt_scan(this);
        if (error)
                return error;

        /* use the default BBT implementation */
        return nand_default_bbt(mtd);
}

static const char *cmd_parse[] = {"cmdlinepart", NULL};
static int __devinit mil_partitions_init(struct gpmi_nfc_data *this)
{
        struct gpmi_nfc_platform_data *pdata = this->pdata;
        struct mil *mil = &this->mil;
        struct mtd_info *mtd = &mil->mtd;

        /* use the command line for simple partitions layout */
        mil->partition_count = parse_mtd_partitions(mtd, cmd_parse,
                                                &mil->partitions, 0);
        if (mil->partition_count)
                return add_mtd_partitions(mtd, mil->partitions,
                                        mil->partition_count);

        /* The complicated partitions layout uses this. */
        if (pdata->partitions && pdata->partition_count > 0)
                return add_mtd_partitions(mtd, pdata->partitions,
                                        pdata->partition_count);
        return add_mtd_device(mtd);
}

static void mil_partitions_exit(struct gpmi_nfc_data *this)
{
        struct mil *mil = &this->mil;

        if (mil->partition_count) {
                struct mtd_info *mtd = &mil->mtd;

                del_mtd_partitions(mtd);
                kfree(mil->partitions);
                mil->partition_count = 0;
        }
}

/* Initializes the MTD Interface Layer */
static int __devinit gpmi_nfc_mil_init(struct gpmi_nfc_data *this)
{
        struct gpmi_nfc_platform_data *pdata = this->pdata;
        struct mil *mil = &this->mil;
        struct mtd_info  *mtd = &mil->mtd;
        struct nand_chip *nand = &mil->nand;
        int error;

        /* Initialize MIL data */
        mil->current_chip       = -1;
        mil->command_length     =  0;
        mil->page_buffer_virt   =  NULL;
        mil->page_buffer_phys   = ~0;
        mil->page_buffer_size   =  0;

        /* Initialize the MTD data structures */
        mtd->priv               = nand;
        mtd->name               = "gpmi-nfc";
        mtd->owner              = THIS_MODULE;
        nand->priv              = this;

        /* Controls */
        nand->select_chip       = mil_select_chip;
        nand->cmd_ctrl          = mil_cmd_ctrl;
        nand->dev_ready         = mil_dev_ready;

        /*
         * Low-level I/O :
         *      We don't support a 16-bit NAND Flash bus,
         *      so we don't implement read_word.
         */
        nand->read_byte         = mil_read_byte;
        nand->read_buf          = mil_read_buf;
        nand->write_buf         = mil_write_buf;

        /* ECC-aware I/O */
        nand->ecc.read_page     = mil_ecc_read_page;
        nand->ecc.write_page    = mil_ecc_write_page;

        /* High-level I/O */
        nand->ecc.read_oob      = mil_ecc_read_oob;
        nand->ecc.write_oob     = mil_ecc_write_oob;

        /* Bad Block Management */
        nand->block_bad         = mil_block_bad;
        nand->scan_bbt          = mil_scan_bbt;
        nand->badblock_pattern  = &gpmi_bbt_descr;

        /* Disallow partial page writes */
        nand->options           |= NAND_NO_SUBPAGE_WRITE;

        /*
         * Tell the NAND Flash MTD system that we'll be handling ECC with our
         * own hardware. It turns out that we still have to fill in the ECC size
         * because the MTD code will divide by it -- even though it doesn't
         * actually care.
         */
        nand->ecc.mode          = NAND_ECC_HW;
        nand->ecc.size          = 1;

        /* use our layout */
        nand->ecc.layout = &mil->oob_layout;

        /* Allocate a temporary DMA buffer for reading ID in the nand_scan() */
        this->nfc_geometry.payload_size_in_bytes        = 1024;
        this->nfc_geometry.auxiliary_size_in_bytes      = 128;
        error = mil_alloc_dma_buffer(this);
        if (error)
                goto exit_dma_allocation;

        printk(KERN_INFO "GPMI-NFC : Scanning for NAND Flash chips...\n");
        error = nand_scan(mtd, pdata->max_chip_count);
        if (error) {
                pr_info("Chip scan failed\n");
                goto exit_nand_scan;
        }

        /* Take over the management of the OOB */
        mil->hooked_block_markbad = mtd->block_markbad;
        mtd->block_markbad        = mil_hook_block_markbad;

        /* Construct partitions as necessary. */
        error = mil_partitions_init(this);
        if (error)
                goto exit_partitions;
        return 0;

exit_partitions:
        nand_release(&mil->mtd);
exit_nand_scan:
        mil_free_dma_buffer(this);
exit_dma_allocation:
        return error;
}

void gpmi_nfc_mil_exit(struct gpmi_nfc_data *this)
{
        struct mil *mil = &this->mil;

        mil_partitions_exit(this);
        nand_release(&mil->mtd);
        mil_free_dma_buffer(this);
}

static int __devinit gpmi_nfc_probe(struct platform_device *pdev)
{
        struct gpmi_nfc_platform_data *pdata = pdev->dev.platform_data;
        struct gpmi_nfc_data *this;
        int error;

        this = kzalloc(sizeof(*this), GFP_KERNEL);
        if (!this) {
                pr_info("Failed to allocate per-device memory\n");
                return -ENOMEM;
        }

        /* Set up our data structures. */
        platform_set_drvdata(pdev, this);
        this->pdev  = pdev;
        this->dev   = &pdev->dev;
        this->pdata = pdata;

        /* setup the platform */
        if (pdata->platform_init) {
                error = pdata->platform_init();
                if (error)
                        goto platform_init_error;
        }

        /* Acquire the resources we need. */
        error = acquire_resources(this);
        if (error)
                goto exit_acquire_resources;

        /* Set up the NFC. */
        error = set_up_nfc_hal(this);
        if (error)
                goto exit_nfc_init;

        /* Initialize the MTD Interface Layer. */
        error = gpmi_nfc_mil_init(this);
        if (error)
                goto exit_mil_init;

        manage_sysfs_files(this, true);
        return 0;

exit_mil_init:
        exit_nfc_hal(this);
exit_nfc_init:
        release_resources(this);
platform_init_error:
exit_acquire_resources:
        platform_set_drvdata(pdev, NULL);
        kfree(this);
        return error;
}

static int __exit gpmi_nfc_remove(struct platform_device *pdev)
{
        struct gpmi_nfc_data *this = platform_get_drvdata(pdev);

        manage_sysfs_files(this, false);
        gpmi_nfc_mil_exit(this);
        exit_nfc_hal(this);
        release_resources(this);
        platform_set_drvdata(pdev, NULL);
        kfree(this);
        return 0;
}

static const struct platform_device_id gpmi_ids[] = {
        {
                .name = "imx23-gpmi-nfc",
                .driver_data = IS_MX23,
        }, {
                .name = "imx28-gpmi-nfc",
                .driver_data = IS_MX28,
        }, {
                .name = "imx50-gpmi-nfc",
                .driver_data = IS_MX50,
        }, {},
};

/* This structure represents this driver to the platform management system. */
static struct platform_driver gpmi_nfc_driver = {
        .driver = {
                .name = "gpmi-nfc",
        },
        .probe   = gpmi_nfc_probe,
        .remove  = __exit_p(gpmi_nfc_remove),
        .id_table = gpmi_ids,
};

static int __init gpmi_nfc_init(void)
{
        int err;

        err = platform_driver_register(&gpmi_nfc_driver);
        if (err == 0)
                printk(KERN_INFO "GPMI NFC driver registered. (IMX)\n");
        else
                pr_err("i.MX GPMI NFC driver registration failed\n");
        return err;
}

static void __exit gpmi_nfc_exit(void)
{
        platform_driver_unregister(&gpmi_nfc_driver);
}

static int __init gpmi_debug_setup(char *__unused)
{
        gpmi_debug = GPMI_DEBUG_INIT;
        return 1;
}
__setup("gpmi_debug_init", gpmi_debug_setup);

module_init(gpmi_nfc_init);
module_exit(gpmi_nfc_exit);

MODULE_AUTHOR("Freescale Semiconductor, Inc.");
MODULE_DESCRIPTION("i.MX GPMI NAND Flash Controller Driver");
MODULE_LICENSE("GPL");