From mboxrd@z Thu Jan  1 00:00:00 1970
From: LW@KARO-electronics.de (=?utf-8?Q?Lothar_Wa=C3=9Fmann?=)
Date: Wed, 13 Apr 2011 21:54:43 +0200
Subject: [PATCH v5 2/4] MTD : add the common code for GPMI controller
	driver
In-Reply-To: <1302675881-18862-3-git-send-email-b32955@freescale.com>
References: <1302675881-18862-1-git-send-email-b32955@freescale.com>
	<1302675881-18862-3-git-send-email-b32955@freescale.com>
Message-ID: <19877.65411.687158.113390@ipc1.ka-ro>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

Huang Shijie writes:
> These files contain the common code for the GPMI driver.
> 
> Signed-off-by: Huang Shijie <b32955@freescale.com>
> ---
>  drivers/mtd/nand/gpmi-nfc/gpmi-nfc-main.c | 2502 +++++++++++++++++++++++++++++
>  drivers/mtd/nand/gpmi-nfc/gpmi-nfc.h      |  488 ++++++
>  2 files changed, 2990 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/mtd/nand/gpmi-nfc/gpmi-nfc-main.c
>  create mode 100644 drivers/mtd/nand/gpmi-nfc/gpmi-nfc.h
> 
> diff --git a/drivers/mtd/nand/gpmi-nfc/gpmi-nfc-main.c b/drivers/mtd/nand/gpmi-nfc/gpmi-nfc-main.c
> new file mode 100644
> index 0000000..33d9f2d
> --- /dev/null
> +++ b/drivers/mtd/nand/gpmi-nfc/gpmi-nfc-main.c
> @@ -0,0 +1,2502 @@
> +/*
> + * 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;
> +
> +static ssize_t show_gpmi_debug(struct device *dev,
> +				struct device_attribute *attr, char *buf)
> +{
> +	return sprintf(buf, "%d\n", gpmi_debug);
> +}
> +
> +static ssize_t
> +store_gpmi_debug(struct device *dev, struct device_attribute *attr,
> +			const char *buf, size_t size)
> +{
> +	const char *p = buf;
> +	unsigned long v;
> +
> +	if (strict_strtoul(p, 0, &v) < 0)
> +		return size;
> +
> +	gpmi_debug = v;
> +	return size;
> +}
> +
> +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 size;
> +
> +	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 DEVICE_ATTR(gpmi_debug, 0644, show_gpmi_debug, store_gpmi_debug);
> +static struct device_attribute *device_attributes[] = {
> +	&dev_attr_ignorebad,
> +	&dev_attr_gpmi_debug,
> +};
> +
> +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;
> +}
> +
> +static inline bool is_ddr_nand(struct nand_chip *chip)
> +{
> +	/* 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)
> +{
> +	struct nand_chip	*chip = &this->mil.nand;
> +
> +	/* the ONFI/TOGGLE nands use 1k ecc chunk size */
> +	if (is_ddr_nand(chip))
> +		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;
> +	struct nand_chip	*chip = &this->mil.nand;
>
inconsistent indentation. You should decide whether to use <TAB> or
<SPACE> for indentation. This is a global issue.

> +	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) {
> +		log("Unsupported page geometry.");
> +		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-culculate DMA page size.
>
s/culculate/calculate/

> +	 * The ONFI nand must do the reculation,
>
s/reculation/recalculation/

> +	 * else it will fail in DMA in some platform(such as imx50).
> +	 */
> +	if (is_ddr_nand(chip))
> +		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 = (geo->metadata_size_in_bytes + 0x3) & ~0x3;
> +	status_size   = (geo->ecc_chunk_count        + 0x3) & ~0x3;
>
You might use:
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(chip))
> +		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.
> +		 */
> +		log("Unsupported page geometry (block mark in ECC): %u:%u",
> +				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, (char *)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)
> +		log("DMA timeout!!!");
> +	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)
> +		log("bch timeout!!!");
> +	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 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) {
> +		log("Can't get resource information for '%s'", resource_name);
> +		return -ENXIO;
> +	}
> +
> +	/* remap the register block */
> +	p = ioremap(r->start, resource_size(r));
> +	if (!p) {
> +		log("Can't remap %s", 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 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) {
> +		log("Can't get resource information for '%s'", resource_name);
> +		return -ENXIO;
> +	}
> +
> +	BUG_ON(r->start != r->end);
> +	err = request_irq(r->start, interrupt_handler, 0, resource_name, this);
> +	if (err) {
> +		log("Can't own %s", 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 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 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) {
> +		log("Can't get resource for DMA");
> +		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;
> +
> +		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 = r->end;
> +	return 0;
> +
> +acquire_err:
> +	log("Can't acquire DMA channel %u", i);
> +	release_dma_channels(this);
> +	return -EINVAL;
> +}
> +
> +static inline int acquire_clock(struct gpmi_nfc_data *this, struct clk **clock)
> +{
> +	struct clk *c;
> +
> +	c = clk_get(&this->pdev->dev, NULL);
> +	if (IS_ERR(c)) {
> +		log("Can't own clock");
> +		return PTR_ERR(c);
> +	}
> +	*clock = c;
> +	return 0;
> +}
> +
> +static void release_clock(struct gpmi_nfc_data *this, struct clk *clock)
> +{
> +	clk_put(clock);
> +}
> +
> +static int 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. */
> +	error = acquire_clock(this, &resources->clock);
> +	if (error)
> +		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;
> +
> +	release_clock(this, 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 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 (GPMI_IS_MX23(this) || GPMI_IS_MX28(this))
> +		nfc = &gpmi_nfc_hal_imx23_imx28;
> +
> +	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;
> +	int                      error;
> +	unsigned int             i;
> +	struct device_attribute  **attr;
> +
> +	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, (void *)destination,
> +						length, DMA_FROM_DEVICE);
> +
> +	if (dma_mapping_error(dev, destination_phys)) {
> +		if (alt_size < length) {
> +			log("Alternate buffer is too small for incoming I/O.");
> +			return -ENOMEM;
> +		}
> +
> +		*use_virt = alt_virt;
> +		*use_phys = alt_phys;
> +	} else {
> +		*use_virt = destination;
> +		*use_phys = destination_phys;
> +	}
> +	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)
> +{
> +	struct device  *dev = this->dev;
> +
> +	if (used_virt == destination)
> +		dma_unmap_single(dev, used_phys, length, DMA_FROM_DEVICE);
> +	else
> +		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) {
> +			log("Alternate buffer is too small for outgoing I/O");
> +			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 device        *dev	= this->dev;
> +	struct nfc_geometry  *geo	= &this->nfc_geometry;
> +	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 = ((char *) 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);
> +	log("allocate DMA buffer error!!");
> +	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)
> +		log("Chip: %u, Error %d", 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 mil            *mil   = &this->mil;
> +	struct nfc_hal        *nfc   =  this->nfc;
> +
> +	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) {
> +		log("Inadequate DMA buffer");
> +		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);
> +	if (error) {
> +		log("Error in ECC-based read: %d", 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];
> +
> +exit_nfc:
> +	read_page_end(this, buf, mtd->writesize,
> +					mil->payload_virt, mil->payload_phys,
> +					nfc_geo->payload_size_in_bytes,
> +					payload_virt, payload_phys);
> +	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) {
> +			log("Inadequate payload DMA buffer");
> +			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) {
> +			log("Inadequate auxiliary DMA buffer");
> +			goto exit_auxiliary;
> +		}
> +	}
> +
> +	/* Ask the NFC. */
> +	error = nfc->send_page(this, payload_phys, auxiliary_phys);
> +	if (error)
> +		log("Error in ECC-based write: %d", 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 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)
> +		log("stride size in page : %d, search areas : %d",
> +			geometry->stride_size_in_pages,
> +			geometry->search_area_stride_exponent);
> +	return 0;
> +}
> +
> +static const char  *fingerprint = "STMP";
> +static int 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 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 Size in Blocks : %u", search_area_size_in_blocks);
> +	pr_info("Search Area Size in Strides: %u", search_area_size_in_strides);
> +	pr_info("Search Area Size in Pages  : %u", 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;
> +}
> +
> +int 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 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 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) {
> +		log("NFC set geometry error : %d", 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() */
> +	this->swap_block_mark = true;
> +	if (GPMI_IS_MX23(this))
> +		this->swap_block_mark = false;
>
if ... else ...?

> +	/* 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";
> +static int 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;
> +	int  error = 0;
> +
> +	/* The complicated partitions layout use this. */
> +	if (pdata->partitions && pdata->partition_count > 0)
> +		return add_mtd_partitions(mtd, pdata->partitions,
> +						pdata->partition_count);
> +
> +	/* use the command line for simple partitions layout */
> +	mil->partition_count = parse_mtd_partitions(mtd,
> +						&cmd_parse,
> +						&mil->partitions, 0);
> +	if (mil->partition_count)
> +		error = add_mtd_partitions(mtd, mil->partitions,
> +						mil->partition_count);
>
I would do the cmdline parsing first, so that any compiled-in
partitioning can be overridden with cmdline parameters.

> +	return error;
> +}
> +
> +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 */
> +int 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	=  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-main";
>
Why not 'gpmi-nfc' like the driver name?


Lothar Wa?mann
-- 
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