Subject: [PATCH v9 2/3] MTD : add helper functions library and header files for GPMI NAND driver

From: [email-masked] (Marek Vasut)
Date: Sat, 20 Aug 2011 13:46:21 +0200

On Wednesday, August 17, 2011 01:50:27 PM Huang Shijie wrote:
> bch-regs.h : registers file for BCH module
> gpmi-regs.h: registers file for GPMI module
> gpmi-lib.c: helper functions library.
> 
> Signed-off-by: Huang Shijie <[email-masked]>
> ---
>  drivers/mtd/nand/gpmi-nand/bch-regs.h  |   88 +++
>  drivers/mtd/nand/gpmi-nand/gpmi-lib.c  |  978
> ++++++++++++++++++++++++++++++++ drivers/mtd/nand/gpmi-nand/gpmi-regs.h | 
> 174 ++++++
>  3 files changed, 1240 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/mtd/nand/gpmi-nand/bch-regs.h
>  create mode 100644 drivers/mtd/nand/gpmi-nand/gpmi-lib.c
>  create mode 100644 drivers/mtd/nand/gpmi-nand/gpmi-regs.h
> 
> diff --git a/drivers/mtd/nand/gpmi-nand/bch-regs.h
> b/drivers/mtd/nand/gpmi-nand/bch-regs.h new file mode 100644
> index 0000000..cec1dfa
> --- /dev/null
> +++ b/drivers/mtd/nand/gpmi-nand/bch-regs.h
> @@ -0,0 +1,88 @@
> +/*
> + * Freescale GPMI NAND Flash Driver
> + *
> + * Copyright 2008-2011 Freescale Semiconductor, Inc.
> + * Copyright 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.
> + */
> +#ifndef __GPMI_NAND_BCH_REGS_H
> +#define __GPMI_NAND_BCH_REGS_H
> +

Aaargh, please remove these separators.

> +/*========================================================================
> ====*/ +#define HW_BCH_CTRL				0x00000000
> +#define HW_BCH_CTRL_SET				0x00000004
> +#define HW_BCH_CTRL_CLR				0x00000008
> +#define HW_BCH_CTRL_TOG				0x0000000c
> +
> +#define BM_BCH_CTRL_COMPLETE_IRQ_EN		(1 << 8)
> +#define BM_BCH_CTRL_COMPLETE_IRQ		(1 << 0)
> +
> +/*========================================================================
> ====*/ +#define HW_BCH_STATUS0				0x00000010
> +#define HW_BCH_MODE				0x00000020
> +#define HW_BCH_ENCODEPTR			0x00000030
> +#define HW_BCH_DATAPTR				0x00000040
> +#define HW_BCH_METAPTR				0x00000050
> +#define HW_BCH_LAYOUTSELECT			0x00000070
> +
> +/*========================================================================
> ====*/ +#define HW_BCH_FLASH0LAYOUT0			0x00000080
> +
> +#define BP_BCH_FLASH0LAYOUT0_NBLOCKS		24
> +#define BM_BCH_FLASH0LAYOUT0_NBLOCKS	(0xff <<
> BP_BCH_FLASH0LAYOUT0_NBLOCKS) +#define BF_BCH_FLASH0LAYOUT0_NBLOCKS(v)		\
> +	(((v) << BP_BCH_FLASH0LAYOUT0_NBLOCKS) & BM_BCH_FLASH0LAYOUT0_NBLOCKS)
> +
> +#define BP_BCH_FLASH0LAYOUT0_META_SIZE		16
> +#define BM_BCH_FLASH0LAYOUT0_META_SIZE	(0xff <<
> BP_BCH_FLASH0LAYOUT0_META_SIZE) +#define
> BF_BCH_FLASH0LAYOUT0_META_SIZE(v)	\
> +	(((v) << BP_BCH_FLASH0LAYOUT0_META_SIZE)\
> +					 & BM_BCH_FLASH0LAYOUT0_META_SIZE)
> +
> +#define BP_BCH_FLASH0LAYOUT0_ECC0		12
> +#define BM_BCH_FLASH0LAYOUT0_ECC0	(0xf << BP_BCH_FLASH0LAYOUT0_ECC0)
> +#define BF_BCH_FLASH0LAYOUT0_ECC0(v)		\
> +	(((v) << BP_BCH_FLASH0LAYOUT0_ECC0) & BM_BCH_FLASH0LAYOUT0_ECC0)
> +
> +#define BP_BCH_FLASH0LAYOUT0_DATA0_SIZE		0
> +#define BM_BCH_FLASH0LAYOUT0_DATA0_SIZE		\
> +			(0xfff << BP_BCH_FLASH0LAYOUT0_DATA0_SIZE)
> +#define BF_BCH_FLASH0LAYOUT0_DATA0_SIZE(v)	\
> +	(((v) << BP_BCH_FLASH0LAYOUT0_DATA0_SIZE)\
> +					 & BM_BCH_FLASH0LAYOUT0_DATA0_SIZE)
> +
> +/*========================================================================
> ====*/ +#define HW_BCH_FLASH0LAYOUT1			0x00000090
> +
> +#define BP_BCH_FLASH0LAYOUT1_PAGE_SIZE		16
> +#define BM_BCH_FLASH0LAYOUT1_PAGE_SIZE		\
> +			(0xffff << BP_BCH_FLASH0LAYOUT1_PAGE_SIZE)
> +#define BF_BCH_FLASH0LAYOUT1_PAGE_SIZE(v)	\
> +	(((v) << BP_BCH_FLASH0LAYOUT1_PAGE_SIZE) \
> +					 & BM_BCH_FLASH0LAYOUT1_PAGE_SIZE)
> +
> +#define BP_BCH_FLASH0LAYOUT1_ECCN		12
> +#define BM_BCH_FLASH0LAYOUT1_ECCN	(0xf << BP_BCH_FLASH0LAYOUT1_ECCN)
> +#define BF_BCH_FLASH0LAYOUT1_ECCN(v)		\
> +	(((v) << BP_BCH_FLASH0LAYOUT1_ECCN) & BM_BCH_FLASH0LAYOUT1_ECCN)
> +
> +#define BP_BCH_FLASH0LAYOUT1_DATAN_SIZE		0
> +#define BM_BCH_FLASH0LAYOUT1_DATAN_SIZE		\
> +			(0xfff << BP_BCH_FLASH0LAYOUT1_DATAN_SIZE)
> +#define BF_BCH_FLASH0LAYOUT1_DATAN_SIZE(v)	\
> +	(((v) << BP_BCH_FLASH0LAYOUT1_DATAN_SIZE) \
> +					 & BM_BCH_FLASH0LAYOUT1_DATAN_SIZE)
> +#endif
> diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
> b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c new file mode 100644
> index 0000000..1368842
> --- /dev/null
> +++ b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
> @@ -0,0 +1,978 @@
> +/*
> + * Freescale GPMI NAND Flash Driver
> + *
> + * Copyright (C) 2008-2011 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 "gpmi-nand.h"
> +#include "gpmi-regs.h"
> +#include "bch-regs.h"
> +
> +struct timing_threshod timing_default_threshold = {
> +	.max_data_setup_cycles       = (BM_GPMI_TIMING0_DATA_SETUP >>
> +						BP_GPMI_TIMING0_DATA_SETUP),
> +	.internal_data_setup_in_ns   = 0,
> +	.max_sample_delay_factor     = (BM_GPMI_CTRL1_RDN_DELAY >>
> +						BP_GPMI_CTRL1_RDN_DELAY),
> +	.max_dll_clock_period_in_ns  = 32,
> +	.max_dll_delay_in_ns         = 16,
> +};
> +
> +int gpmi_init(struct gpmi_nand_data *this)
> +{
> +	struct resources *r = &this->resources;
> +	int ret;
> +
> +	ret = clk_enable(r->clock);
> +	if (ret)
> +		goto err_out;
> +	ret = mxs_reset_block(r->gpmi_regs);
> +	if (ret)
> +		goto err_out;
> +
> +	/* Choose NAND mode. */
> +	writel(BM_GPMI_CTRL1_GPMI_MODE, r->gpmi_regs + HW_GPMI_CTRL1_CLR);
> +
> +	/* Set the IRQ polarity. */
> +	writel(BM_GPMI_CTRL1_ATA_IRQRDY_POLARITY,
> +				r->gpmi_regs + HW_GPMI_CTRL1_SET);
> +
> +	/* Disable Write-Protection. */
> +	writel(BM_GPMI_CTRL1_DEV_RESET, r->gpmi_regs + HW_GPMI_CTRL1_SET);
> +
> +	/* Select BCH ECC. */
> +	writel(BM_GPMI_CTRL1_BCH_MODE, r->gpmi_regs + HW_GPMI_CTRL1_SET);
> +
> +	clk_disable(r->clock);
> +	return 0;
> +err_out:
> +	return ret;
> +}
> +
> +/* This is very useful! */

Really? Cool, what for ?
btw. this should really be enclosed in some #ifdef debug or whatnot.

> +void gpmi_show_regs(struct gpmi_nand_data *this)
> +{
> +	struct resources *r = &this->resources;
> +	u32 reg;
> +	int i;
> +	int n;
> +
> +	n = HW_GPMI_DEBUG / 0x10 + 1;
> +
> +	pr_info("-------------- Show GPMI registers ----------\n");
> +	for (i = 0; i <= n; i++) {
> +		reg = readl(r->gpmi_regs + i * 0x10);
> +		pr_info("offset 0x%.3x : 0x%.8x\n", i * 0x10, reg);
> +	}
> +	pr_info("-------------- Show GPMI registers end ----------\n");
> +}
> +
> +/* Configures the geometry for BCH.  */
> +int bch_set_geometry(struct gpmi_nand_data *this)
> +{
> +	struct resources *r = &this->resources;
> +	struct bch_geometry *bch_geo = &this->bch_geometry;
> +	unsigned int block_count;
> +	unsigned int block_size;
> +	unsigned int metadata_size;
> +	unsigned int ecc_strength;
> +	unsigned int page_size;
> +	int ret;
> +
> +	if (common_nfc_set_geometry(this))
> +		return !0;
> +
> +	block_count   = bch_geo->ecc_chunk_count - 1;
> +	block_size    = bch_geo->ecc_chunk_size_in_bytes;
> +	metadata_size = bch_geo->metadata_size_in_bytes;
> +	ecc_strength  = bch_geo->ecc_strength >> 1;
> +	page_size     = bch_geo->page_size_in_bytes;
> +
> +	ret = clk_enable(r->clock);
> +	if (ret)
> +		goto err_out;
> +	ret = mxs_reset_block(r->bch_regs);
> +	if (ret)
> +		goto err_out;
> +
> +	/* Configure layout 0. */
> +	writel(BF_BCH_FLASH0LAYOUT0_NBLOCKS(block_count)
> +			| BF_BCH_FLASH0LAYOUT0_META_SIZE(metadata_size)
> +			| BF_BCH_FLASH0LAYOUT0_ECC0(ecc_strength)
> +			| BF_BCH_FLASH0LAYOUT0_DATA0_SIZE(block_size),
> +			r->bch_regs + HW_BCH_FLASH0LAYOUT0);
> +
> +	writel(BF_BCH_FLASH0LAYOUT1_PAGE_SIZE(page_size)
> +			| BF_BCH_FLASH0LAYOUT1_ECCN(ecc_strength)
> +			| BF_BCH_FLASH0LAYOUT1_DATAN_SIZE(block_size),
> +			r->bch_regs + HW_BCH_FLASH0LAYOUT1);
> +
> +	/* Set *all* chip selects to use layout 0. */
> +	writel(0, r->bch_regs + HW_BCH_LAYOUTSELECT);
> +
> +	/* Enable interrupts. */
> +	writel(BM_BCH_CTRL_COMPLETE_IRQ_EN,
> +				r->bch_regs + HW_BCH_CTRL_SET);
> +
> +	clk_disable(r->clock);
> +	return 0;
> +err_out:
> +	return ret;
> +}
> +
> +/*
> + * 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.
> + */
> +static int gpmi_nfc_compute_hardware_timing(struct gpmi_nand_data *this,
> +					struct gpmi_nfc_hardware_timing *hw)
> +{
> +	struct gpmi_nand_platform_data *pdata = this->pdata;
> +	struct timing_threshod *nfc = &timing_default_threshold;
> +	struct nand_chip *nand = &this->mil.nand;
> +	struct nand_timing target = this->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;
> +}
> +
> +/* Begin the I/O */
> +void gpmi_begin(struct gpmi_nand_data *this)
> +{
> +	struct resources *r = &this->resources;
> +	struct timing_threshod *nfc = &timing_default_threshold;
> +	unsigned char  *gpmi_regs = r->gpmi_regs;
> +	unsigned int   clock_period_in_ns;
> +	uint32_t       reg;
> +	unsigned int   dll_wait_time_in_us;
> +	struct gpmi_nfc_hardware_timing  hw;
> +	int ret;
> +
> +	/* Enable the clock. */
> +	ret = clk_enable(r->clock);
> +	if (ret) {
> +		pr_info("We failed in enable the clk\n");
> +		goto err_out;
> +	}
> +
> +	/* set ready/busy timeout */
> +	writel(0x500 << 16, gpmi_regs + HW_GPMI_TIMING1);
> +
> +	/* Get the timing information we need. */
> +	nfc->clock_frequency_in_hz = clk_get_rate(r->clock);
> +	clock_period_in_ns = 1000000000 / nfc->clock_frequency_in_hz;
> +
> +	gpmi_nfc_compute_hardware_timing(this, &hw);
> +
> +	/* Set up all the simple timing parameters. */
> +	reg = BF_GPMI_TIMING0_ADDRESS_SETUP(hw.address_setup_in_cycles) |
> +		BF_GPMI_TIMING0_DATA_HOLD(hw.data_hold_in_cycles)         |
> +		BF_GPMI_TIMING0_DATA_SETUP(hw.data_setup_in_cycles)       ;
> +
> +	writel(reg, gpmi_regs + HW_GPMI_TIMING0);
> +
> +	/*
> +	 * HEY - PAY ATTENTION!

Please fix this comment and pay attention to other comments ;-)

> +	 *
> +	 * DLL_ENABLE must be set to zero when setting RDN_DELAY or HALF_PERIOD.
> +	 */
> +	writel(BM_GPMI_CTRL1_DLL_ENABLE, gpmi_regs + HW_GPMI_CTRL1_CLR);
> +
> +	/* Clear out the DLL control fields. */
> +	writel(BM_GPMI_CTRL1_RDN_DELAY,   gpmi_regs + HW_GPMI_CTRL1_CLR);
> +	writel(BM_GPMI_CTRL1_HALF_PERIOD, gpmi_regs + HW_GPMI_CTRL1_CLR);
> +
> +	/* If no sample delay is called for, return immediately. */
> +	if (!hw.sample_delay_factor)
> +		return;
> +
> +	/* Configure the HALF_PERIOD flag. */
> +	if (hw.use_half_periods)
> +		writel(BM_GPMI_CTRL1_HALF_PERIOD,
> +						gpmi_regs + HW_GPMI_CTRL1_SET);
> +
> +	/* Set the delay factor. */
> +	writel(BF_GPMI_CTRL1_RDN_DELAY(hw.sample_delay_factor),
> +						gpmi_regs + HW_GPMI_CTRL1_SET);
> +
> +	/* Enable the DLL. */
> +	writel(BM_GPMI_CTRL1_DLL_ENABLE, gpmi_regs + HW_GPMI_CTRL1_SET);
> +
> +	/*
> +	 * After we enable the GPMI DLL, we have to wait 64 clock cycles before
> +	 * we can use the GPMI.
> +	 *
> +	 * Calculate the amount of time we need to wait, in microseconds.
> +	 */
> +	dll_wait_time_in_us = (clock_period_in_ns * 64) / 1000;
> +
> +	if (!dll_wait_time_in_us)
> +		dll_wait_time_in_us = 1;
> +
> +	/* Wait for the DLL to settle. */
> +	udelay(dll_wait_time_in_us);
> +
> +err_out:
> +	return;
> +}
> +
> +void gpmi_end(struct gpmi_nand_data *this)
> +{
> +	struct resources *r = &this->resources;
> +	clk_disable(r->clock);
> +}
> +
> +/* Clears a BCH interrupt. */
> +void gpmi_clear_bch(struct gpmi_nand_data *this)
> +{
> +	struct resources *r = &this->resources;
> +	writel(BM_BCH_CTRL_COMPLETE_IRQ, r->bch_regs + HW_BCH_CTRL_CLR);
> +}
> +
> +/* Returns the Ready/Busy status of the given chip. */
> +int gpmi_is_ready(struct gpmi_nand_data *this, unsigned chip)
> +{
> +	struct resources *r = &this->resources;
> +	uint32_t mask;
> +	uint32_t reg;
> +
> +	if (GPMI_IS_MX23(this)) {
> +		mask = MX23_BM_GPMI_DEBUG_READY0 << chip;
> +		reg = readl(r->gpmi_regs + HW_GPMI_DEBUG);
> +	} else if (GPMI_IS_MX28(this)) {
> +		mask = MX28_BF_GPMI_STAT_READY_BUSY(1 << chip);
> +		reg = readl(r->gpmi_regs + HW_GPMI_STAT);
> +	} else
> +		BUG();
> +	return !!(reg & mask);
> +}
> +
> +static inline void set_dma_type(struct gpmi_nand_data *this,
> +					enum dma_ops_type type)
> +{
> +	this->last_dma_type = this->dma_type;
> +	this->dma_type = type;
> +}
> +
> +int gpmi_send_command(struct gpmi_nand_data *this)
> +{
> +	struct dma_chan *channel = get_dma_chan(this);
> +	struct mil *mil	= &this->mil;
> +	struct dma_async_tx_descriptor *desc;
> +	struct scatterlist *sgl;
> +	int chip = mil->current_chip;
> +	u32 pio[3];
> +
> +	/* [1] send out the PIO words */
> +	pio[0] = BF_GPMI_CTRL0_COMMAND_MODE(BV_GPMI_CTRL0_COMMAND_MODE__WRITE)
> +		| BM_GPMI_CTRL0_WORD_LENGTH
> +		| BF_GPMI_CTRL0_CS(chip, this)
> +		| BF_GPMI_CTRL0_LOCK_CS(LOCK_CS_ENABLE, this)
> +		| BF_GPMI_CTRL0_ADDRESS(BV_GPMI_CTRL0_ADDRESS__NAND_CLE)
> +		| BM_GPMI_CTRL0_ADDRESS_INCREMENT
> +		| BF_GPMI_CTRL0_XFER_COUNT(mil->command_length);
> +	pio[1] = pio[2] = 0;
> +	desc = channel->device->device_prep_slave_sg(channel,
> +					(struct scatterlist *)pio,
> +					ARRAY_SIZE(pio), DMA_NONE, 0);
> +	if (!desc) {
> +		pr_info("step 1 error\n");
> +		return -1;
> +	}
> +
> +	/* [2] send out the COMMAND + ADDRESS string stored in @buffer */
> +	sgl = &mil->cmd_sgl;
> +
> +	sg_init_one(sgl, mil->cmd_buffer, mil->command_length);
> +	dma_map_sg(this->dev, sgl, 1, DMA_TO_DEVICE);
> +	desc = channel->device->device_prep_slave_sg(channel,
> +					sgl, 1, DMA_TO_DEVICE, 1);
> +	if (!desc) {
> +		pr_info("step 2 error\n");
> +		return -1;
> +	}
> +
> +	/* [3] submit the DMA */
> +	set_dma_type(this, DMA_FOR_COMMAND);
> +	return start_dma_without_bch_irq(this, desc);
> +}
> +
> +int gpmi_send_data(struct gpmi_nand_data *this)
> +{
> +	struct dma_async_tx_descriptor *desc;
> +	struct dma_chan *channel = get_dma_chan(this);
> +	struct mil *mil	= &this->mil;
> +	int chip = mil->current_chip;
> +	uint32_t command_mode;
> +	uint32_t address;
> +	u32 pio[2];
> +
> +	/* [1] PIO */
> +	command_mode = BV_GPMI_CTRL0_COMMAND_MODE__WRITE;
> +	address      = BV_GPMI_CTRL0_ADDRESS__NAND_DATA;
> +
> +	pio[0] = BF_GPMI_CTRL0_COMMAND_MODE(command_mode)
> +		| BM_GPMI_CTRL0_WORD_LENGTH
> +		| BF_GPMI_CTRL0_CS(chip, this)
> +		| BF_GPMI_CTRL0_LOCK_CS(LOCK_CS_ENABLE, this)
> +		| BF_GPMI_CTRL0_ADDRESS(address)
> +		| BF_GPMI_CTRL0_XFER_COUNT(mil->upper_len);
> +	pio[1] = 0;
> +	desc = channel->device->device_prep_slave_sg(channel,
> +					(struct scatterlist *)pio,
> +					ARRAY_SIZE(pio), DMA_NONE, 0);
> +	if (!desc) {
> +		pr_info("step 1 error\n");
> +		return -1;
> +	}
> +
> +	/* [2] send DMA request */
> +	prepare_data_dma(this, DMA_TO_DEVICE);
> +	desc = channel->device->device_prep_slave_sg(channel, &mil->data_sgl,
> +						1, DMA_TO_DEVICE, 1);
> +	if (!desc) {
> +		pr_info("step 2 error\n");
> +		return -1;
> +	}
> +	/* [3] submit the DMA */
> +	set_dma_type(this, DMA_FOR_WRITE_DATA);
> +	return start_dma_without_bch_irq(this, desc);
> +}
> +
> +int gpmi_read_data(struct gpmi_nand_data *this)
> +{
> +	struct dma_async_tx_descriptor *desc;
> +	struct dma_chan *channel = get_dma_chan(this);
> +	struct mil *mil = &this->mil;
> +	int chip = mil->current_chip;
> +	u32 pio[2];
> +
> +	/* [1] : send PIO */
> +	pio[0] = BF_GPMI_CTRL0_COMMAND_MODE(BV_GPMI_CTRL0_COMMAND_MODE__READ)
> +		| BM_GPMI_CTRL0_WORD_LENGTH
> +		| BF_GPMI_CTRL0_CS(chip, this)
> +		| BF_GPMI_CTRL0_LOCK_CS(LOCK_CS_ENABLE, this)
> +		| BF_GPMI_CTRL0_ADDRESS(BV_GPMI_CTRL0_ADDRESS__NAND_DATA)
> +		| BF_GPMI_CTRL0_XFER_COUNT(mil->upper_len);
> +	pio[1] = 0;
> +	desc = channel->device->device_prep_slave_sg(channel,
> +					(struct scatterlist *)pio,
> +					ARRAY_SIZE(pio), DMA_NONE, 0);
> +	if (!desc) {
> +		pr_info("step 1 error\n");
> +		return -1;
> +	}
> +
> +	/* [2] : send DMA request */
> +	prepare_data_dma(this, DMA_FROM_DEVICE);
> +	desc = channel->device->device_prep_slave_sg(channel, &mil->data_sgl,
> +						1, DMA_FROM_DEVICE, 1);
> +	if (!desc) {
> +		pr_info("step 2 error\n");
> +		return -1;
> +	}
> +
> +	/* [3] : submit the DMA */
> +	set_dma_type(this, DMA_FOR_READ_DATA);
> +	return start_dma_without_bch_irq(this, desc);
> +}
> +
> +int gpmi_send_page(struct gpmi_nand_data *this,
> +			dma_addr_t payload, dma_addr_t auxiliary)
> +{
> +	struct bch_geometry *geo = &this->bch_geometry;
> +	uint32_t command_mode;
> +	uint32_t address;
> +	uint32_t ecc_command;
> +	uint32_t buffer_mask;
> +	struct dma_async_tx_descriptor *desc;
> +	struct dma_chan *channel = get_dma_chan(this);
> +	struct mil *mil = &this->mil;
> +	int chip = mil->current_chip;
> +	u32 pio[6];
> +
> +	/* A DMA descriptor that does an ECC page read. */
> +	command_mode = BV_GPMI_CTRL0_COMMAND_MODE__WRITE;
> +	address      = BV_GPMI_CTRL0_ADDRESS__NAND_DATA;
> +	ecc_command  = BV_GPMI_ECCCTRL_ECC_CMD__BCH_ENCODE;
> +	buffer_mask  = BV_GPMI_ECCCTRL_BUFFER_MASK__BCH_PAGE |
> +				BV_GPMI_ECCCTRL_BUFFER_MASK__BCH_AUXONLY;
> +
> +	pio[0] = BF_GPMI_CTRL0_COMMAND_MODE(command_mode)
> +		| BM_GPMI_CTRL0_WORD_LENGTH
> +		| BF_GPMI_CTRL0_CS(chip, this)
> +		| BF_GPMI_CTRL0_LOCK_CS(LOCK_CS_ENABLE, this)
> +		| BF_GPMI_CTRL0_ADDRESS(address)
> +		| BF_GPMI_CTRL0_XFER_COUNT(0);
> +	pio[1] = 0;
> +	pio[2] = BM_GPMI_ECCCTRL_ENABLE_ECC
> +		| BF_GPMI_ECCCTRL_ECC_CMD(ecc_command)
> +		| BF_GPMI_ECCCTRL_BUFFER_MASK(buffer_mask);
> +	pio[3] = geo->page_size_in_bytes;
> +	pio[4] = payload;
> +	pio[5] = auxiliary;
> +
> +	desc = channel->device->device_prep_slave_sg(channel,
> +					(struct scatterlist *)pio,
> +					ARRAY_SIZE(pio), DMA_NONE, 0);
> +	if (!desc) {
> +		pr_info("step 2 error\n");
> +		return -1;
> +	}
> +	set_dma_type(this, DMA_FOR_WRITE_ECC_PAGE);
> +	return start_dma_with_bch_irq(this, desc);
> +}
> +
> +int gpmi_read_page(struct gpmi_nand_data *this,
> +				dma_addr_t payload, dma_addr_t auxiliary)
> +{
> +	struct bch_geometry *geo = &this->bch_geometry;
> +	uint32_t command_mode;
> +	uint32_t address;
> +	uint32_t ecc_command;
> +	uint32_t buffer_mask;
> +	struct dma_async_tx_descriptor *desc;
> +	struct dma_chan *channel = get_dma_chan(this);
> +	struct mil *mil = &this->mil;
> +	int chip = mil->current_chip;
> +	u32 pio[6];
> +
> +	/* [1] Wait for the chip to report ready. */
> +	command_mode = BV_GPMI_CTRL0_COMMAND_MODE__WAIT_FOR_READY;
> +	address      = BV_GPMI_CTRL0_ADDRESS__NAND_DATA;
> +
> +	pio[0] =  BF_GPMI_CTRL0_COMMAND_MODE(command_mode)
> +		| BM_GPMI_CTRL0_WORD_LENGTH
> +		| BF_GPMI_CTRL0_CS(chip, this)
> +		| BF_GPMI_CTRL0_LOCK_CS(LOCK_CS_ENABLE, this)
> +		| BF_GPMI_CTRL0_ADDRESS(address)
> +		| BF_GPMI_CTRL0_XFER_COUNT(0);
> +	pio[1] = 0;
> +	desc = channel->device->device_prep_slave_sg(channel,
> +				(struct scatterlist *)pio, 2, DMA_NONE, 0);
> +	if (!desc) {
> +		pr_info("step 1 error\n");
> +		return -1;
> +	}
> +
> +	/* [2] Enable the BCH block and read. */
> +	command_mode = BV_GPMI_CTRL0_COMMAND_MODE__READ;
> +	address      = BV_GPMI_CTRL0_ADDRESS__NAND_DATA;
> +	ecc_command  = BV_GPMI_ECCCTRL_ECC_CMD__BCH_DECODE;
> +	buffer_mask  = BV_GPMI_ECCCTRL_BUFFER_MASK__BCH_PAGE
> +			| BV_GPMI_ECCCTRL_BUFFER_MASK__BCH_AUXONLY;
> +
> +	pio[0] =  BF_GPMI_CTRL0_COMMAND_MODE(command_mode)
> +		| BM_GPMI_CTRL0_WORD_LENGTH
> +		| BF_GPMI_CTRL0_CS(chip, this)
> +		| BF_GPMI_CTRL0_LOCK_CS(LOCK_CS_ENABLE, this)
> +		| BF_GPMI_CTRL0_ADDRESS(address)
> +		| BF_GPMI_CTRL0_XFER_COUNT(geo->page_size_in_bytes);
> +
> +	pio[1] = 0;
> +	pio[2] =  BM_GPMI_ECCCTRL_ENABLE_ECC
> +		| BF_GPMI_ECCCTRL_ECC_CMD(ecc_command)
> +		| BF_GPMI_ECCCTRL_BUFFER_MASK(buffer_mask);
> +	pio[3] = geo->page_size_in_bytes;
> +	pio[4] = payload;
> +	pio[5] = auxiliary;
> +	desc = channel->device->device_prep_slave_sg(channel,
> +					(struct scatterlist *)pio,
> +					ARRAY_SIZE(pio), DMA_NONE, 1);
> +	if (!desc) {
> +		pr_info("step 2 error\n");
> +		return -1;
> +	}
> +
> +	/* [3] Disable the BCH block */
> +	command_mode = BV_GPMI_CTRL0_COMMAND_MODE__WAIT_FOR_READY;
> +	address      = BV_GPMI_CTRL0_ADDRESS__NAND_DATA;
> +
> +	pio[0] = BF_GPMI_CTRL0_COMMAND_MODE(command_mode)
> +		| BM_GPMI_CTRL0_WORD_LENGTH
> +		| BF_GPMI_CTRL0_CS(chip, this)
> +		| BF_GPMI_CTRL0_LOCK_CS(LOCK_CS_ENABLE, this)
> +		| BF_GPMI_CTRL0_ADDRESS(address)
> +		| BF_GPMI_CTRL0_XFER_COUNT(geo->page_size_in_bytes);
> +	pio[1] = 0;
> +	desc = channel->device->device_prep_slave_sg(channel,
> +				(struct scatterlist *)pio, 2, DMA_NONE, 1);
> +	if (!desc) {
> +		pr_info("step 3 error\n");
> +		return -1;
> +	}
> +
> +	/* [4] submit the DMA */
> +	set_dma_type(this, DMA_FOR_READ_ECC_PAGE);
> +	return start_dma_with_bch_irq(this, desc);
> +}
> diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-regs.h
> b/drivers/mtd/nand/gpmi-nand/gpmi-regs.h new file mode 100644
> index 0000000..c0381cd
> --- /dev/null
> +++ b/drivers/mtd/nand/gpmi-nand/gpmi-regs.h
> @@ -0,0 +1,174 @@
> +/*
> + * Freescale GPMI NAND Flash Driver
> + *
> + * Copyright 2008-2011 Freescale Semiconductor, Inc.
> + * Copyright 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.
> + */
> +#ifndef __GPMI_NAND_GPMI_REGS_H
> +#define __GPMI_NAND_GPMI_REGS_H
> +
> +/*========================================================================
> ====*/ +#define HW_GPMI_CTRL0					0x00000000
> +#define HW_GPMI_CTRL0_SET				0x00000004
> +#define HW_GPMI_CTRL0_CLR				0x00000008
> +#define HW_GPMI_CTRL0_TOG				0x0000000c
> +
> +#define BP_GPMI_CTRL0_COMMAND_MODE			24
> +#define BM_GPMI_CTRL0_COMMAND_MODE	(3 << BP_GPMI_CTRL0_COMMAND_MODE)
> +#define BF_GPMI_CTRL0_COMMAND_MODE(v)	\
> +	(((v) << BP_GPMI_CTRL0_COMMAND_MODE) & BM_GPMI_CTRL0_COMMAND_MODE)
> +#define BV_GPMI_CTRL0_COMMAND_MODE__WRITE		0x0
> +#define BV_GPMI_CTRL0_COMMAND_MODE__READ		0x1
> +#define BV_GPMI_CTRL0_COMMAND_MODE__READ_AND_COMPARE	0x2
> +#define BV_GPMI_CTRL0_COMMAND_MODE__WAIT_FOR_READY	0x3
> +
> +#define BM_GPMI_CTRL0_WORD_LENGTH			(1 << 23)
> +#define BV_GPMI_CTRL0_WORD_LENGTH__16_BIT		0x0
> +#define BV_GPMI_CTRL0_WORD_LENGTH__8_BIT		0x1
> +
> +/*
> + *  Difference in LOCK_CS between imx23 and imx28 :
> + *  This bit may impact the _POWER_ consumption. So some chips
> + *  do not set it.
> + */
> +#define MX23_BP_GPMI_CTRL0_LOCK_CS			22
> +#define MX28_BP_GPMI_CTRL0_LOCK_CS			27
> +#define LOCK_CS_ENABLE					0x1
> +#define BF_GPMI_CTRL0_LOCK_CS(v, x)			0x0
> +
> +/* Difference in CS between imx23 and imx28 */
> +#define BP_GPMI_CTRL0_CS				20
> +#define MX23_BM_GPMI_CTRL0_CS		(3 << BP_GPMI_CTRL0_CS)
> +#define MX28_BM_GPMI_CTRL0_CS		(7 << BP_GPMI_CTRL0_CS)
> +#define BF_GPMI_CTRL0_CS(v, x)		(((v) << BP_GPMI_CTRL0_CS) & \
> +						(GPMI_IS_MX23((x)) \
> +						? MX23_BM_GPMI_CTRL0_CS	\
> +						: MX28_BM_GPMI_CTRL0_CS))
> +
> +#define BP_GPMI_CTRL0_ADDRESS				17
> +#define BM_GPMI_CTRL0_ADDRESS		(3 << BP_GPMI_CTRL0_ADDRESS)
> +#define BF_GPMI_CTRL0_ADDRESS(v)	\
> +		(((v) << BP_GPMI_CTRL0_ADDRESS) & BM_GPMI_CTRL0_ADDRESS)
> +#define BV_GPMI_CTRL0_ADDRESS__NAND_DATA		0x0
> +#define BV_GPMI_CTRL0_ADDRESS__NAND_CLE			0x1
> +#define BV_GPMI_CTRL0_ADDRESS__NAND_ALE			0x2
> +
> +#define BM_GPMI_CTRL0_ADDRESS_INCREMENT			(1 << 16)
> +#define BV_GPMI_CTRL0_ADDRESS_INCREMENT__DISABLED	0x0
> +#define BV_GPMI_CTRL0_ADDRESS_INCREMENT__ENABLED	0x1
> +
> +#define BP_GPMI_CTRL0_XFER_COUNT			0
> +#define BM_GPMI_CTRL0_XFER_COUNT	(0xffff << BP_GPMI_CTRL0_XFER_COUNT)
> +#define BF_GPMI_CTRL0_XFER_COUNT(v)	\
> +		(((v) << BP_GPMI_CTRL0_XFER_COUNT) & BM_GPMI_CTRL0_XFER_COUNT)
> +
> +/*========================================================================
> ====*/ +#define HW_GPMI_COMPARE					0x00000010
> +/*========================================================================
> ====*/ +#define HW_GPMI_ECCCTRL					0x00000020
> +#define HW_GPMI_ECCCTRL_SET				0x00000024
> +#define HW_GPMI_ECCCTRL_CLR				0x00000028
> +#define HW_GPMI_ECCCTRL_TOG				0x0000002c
> +
> +#define BP_GPMI_ECCCTRL_ECC_CMD				13
> +#define BM_GPMI_ECCCTRL_ECC_CMD		(3 << BP_GPMI_ECCCTRL_ECC_CMD)
> +#define BF_GPMI_ECCCTRL_ECC_CMD(v)	\
> +		(((v) << BP_GPMI_ECCCTRL_ECC_CMD) & BM_GPMI_ECCCTRL_ECC_CMD)
> +#define BV_GPMI_ECCCTRL_ECC_CMD__BCH_DECODE		0x0
> +#define BV_GPMI_ECCCTRL_ECC_CMD__BCH_ENCODE		0x1
> +
> +#define BM_GPMI_ECCCTRL_ENABLE_ECC			(1 << 12)
> +#define BV_GPMI_ECCCTRL_ENABLE_ECC__ENABLE		0x1
> +#define BV_GPMI_ECCCTRL_ENABLE_ECC__DISABLE		0x0
> +
> +#define BP_GPMI_ECCCTRL_BUFFER_MASK			0
> +#define BM_GPMI_ECCCTRL_BUFFER_MASK	(0x1ff << BP_GPMI_ECCCTRL_BUFFER_MASK)
> +#define BF_GPMI_ECCCTRL_BUFFER_MASK(v)	\
> +	(((v) << BP_GPMI_ECCCTRL_BUFFER_MASK) & BM_GPMI_ECCCTRL_BUFFER_MASK)
> +#define BV_GPMI_ECCCTRL_BUFFER_MASK__BCH_AUXONLY	0x100
> +#define BV_GPMI_ECCCTRL_BUFFER_MASK__BCH_PAGE		0x1FF
> +
> +/*========================================================================
> ====*/ +#define HW_GPMI_ECCCOUNT				0x00000030
> +#define HW_GPMI_PAYLOAD					0x00000040
> +#define HW_GPMI_AUXILIARY				0x00000050
> +/*========================================================================
> ====*/ +#define HW_GPMI_CTRL1					0x00000060
> +#define HW_GPMI_CTRL1_SET				0x00000064
> +#define HW_GPMI_CTRL1_CLR				0x00000068
> +#define HW_GPMI_CTRL1_TOG				0x0000006c
> +
> +#define BM_GPMI_CTRL1_BCH_MODE				(1 << 18)
> +
> +#define BP_GPMI_CTRL1_DLL_ENABLE			17
> +#define BM_GPMI_CTRL1_DLL_ENABLE	(1 << BP_GPMI_CTRL1_DLL_ENABLE)
> +
> +#define BP_GPMI_CTRL1_HALF_PERIOD			16
> +#define BM_GPMI_CTRL1_HALF_PERIOD	(1 << BP_GPMI_CTRL1_HALF_PERIOD)
> +
> +#define BP_GPMI_CTRL1_RDN_DELAY				12
> +#define BM_GPMI_CTRL1_RDN_DELAY		(0xf << BP_GPMI_CTRL1_RDN_DELAY)
> +#define BF_GPMI_CTRL1_RDN_DELAY(v)	\
> +		(((v) << BP_GPMI_CTRL1_RDN_DELAY) & BM_GPMI_CTRL1_RDN_DELAY)
> +
> +#define BM_GPMI_CTRL1_DEV_RESET				(1 << 3)
> +#define BV_GPMI_CTRL1_DEV_RESET__ENABLED		0x0
> +#define BV_GPMI_CTRL1_DEV_RESET__DISABLED		0x1
> +
> +#define BM_GPMI_CTRL1_ATA_IRQRDY_POLARITY		(1 << 2)
> +#define BV_GPMI_CTRL1_ATA_IRQRDY_POLARITY__ACTIVELOW	0x0
> +#define BV_GPMI_CTRL1_ATA_IRQRDY_POLARITY__ACTIVEHIGH	0x1
> +
> +#define BM_GPMI_CTRL1_CAMERA_MODE			(1 << 1)
> +#define BV_GPMI_CTRL1_GPMI_MODE__NAND			0x0
> +#define BV_GPMI_CTRL1_GPMI_MODE__ATA			0x1
> +
> +#define BM_GPMI_CTRL1_GPMI_MODE				(1 << 0)
> +
> +/*========================================================================
> ====*/ +#define HW_GPMI_TIMING0					0x00000070
> +
> +#define BP_GPMI_TIMING0_ADDRESS_SETUP			16
> +#define BM_GPMI_TIMING0_ADDRESS_SETUP	(0xff <<
> BP_GPMI_TIMING0_ADDRESS_SETUP) +#define BF_GPMI_TIMING0_ADDRESS_SETUP(v)	\
> +	(((v) << BP_GPMI_TIMING0_ADDRESS_SETUP) & BM_GPMI_TIMING0_ADDRESS_SETUP)
> +
> +#define BP_GPMI_TIMING0_DATA_HOLD			8
> +#define BM_GPMI_TIMING0_DATA_HOLD	(0xff << BP_GPMI_TIMING0_DATA_HOLD)
> +#define BF_GPMI_TIMING0_DATA_HOLD(v)		\
> +	(((v) << BP_GPMI_TIMING0_DATA_HOLD) & BM_GPMI_TIMING0_DATA_HOLD)
> +
> +#define BP_GPMI_TIMING0_DATA_SETUP			0
> +#define BM_GPMI_TIMING0_DATA_SETUP	(0xff << BP_GPMI_TIMING0_DATA_SETUP)
> +#define BF_GPMI_TIMING0_DATA_SETUP(v)		\
> +	(((v) << BP_GPMI_TIMING0_DATA_SETUP) & BM_GPMI_TIMING0_DATA_SETUP)
> +
> +/*========================================================================
> ====*/ +#define HW_GPMI_TIMING1					0x00000080
> +#define HW_GPMI_TIMING2					0x00000090
> +#define HW_GPMI_DATA					0x000000a0
> +/*============================ MX28 uses this to detect READY
> ================*/ +#define HW_GPMI_STAT					0x000000b0
> +#define MX28_BP_GPMI_STAT_READY_BUSY			24
> +#define MX28_BM_GPMI_STAT_READY_BUSY	(0xff <<
> MX28_BP_GPMI_STAT_READY_BUSY) +#define MX28_BF_GPMI_STAT_READY_BUSY(v)		
\
> +	(((v) << MX28_BP_GPMI_STAT_READY_BUSY) & MX28_BM_GPMI_STAT_READY_BUSY)
> +/*============================ MX23 uses this to detect READY
> ================*/ +#define HW_GPMI_DEBUG					0x000000c0
> +#define MX23_BP_GPMI_DEBUG_READY0			28
> +#define MX23_BM_GPMI_DEBUG_READY0	(1 << MX23_BP_GPMI_DEBUG_READY0)
> +#endif