mtd: add helper functions library and header files for GPMI NAND driver

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 <b32955@freescale.com>
Acked-by: Marek Vasut <marek.vasut@gmail.com>
Tested-by: Koen Beel <koen.beel@barco.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@intel.com>

3 files changed, 1313 insertions, 0 deletions

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 000000000000..4effb8c579db
--- /dev/null
+++ b/drivers/mtd/nand/gpmi-nand/bch-regs.h
@@ -0,0 +1,84 @@
+/*
+ * 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
+
+#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 000000000000..de4db7604a3f
--- /dev/null
+++ b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
@@ -0,0 +1,1057 @@
+/*
+ * 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 <linux/mtd/gpmi-nand.h>
+#include <linux/delay.h>
+#include <linux/clk.h>
+#include <mach/mxs.h>
+
+#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,
+};
+
+/*
+ * Clear the bit and poll it cleared.  This is usually called with
+ * a reset address and mask being either SFTRST(bit 31) or CLKGATE
+ * (bit 30).
+ */
+static int clear_poll_bit(void __iomem *addr, u32 mask)
+{
+	int timeout = 0x400;
+
+	/* clear the bit */
+	__mxs_clrl(mask, addr);
+
+	/*
+	 * SFTRST needs 3 GPMI clocks to settle, the reference manual
+	 * recommends to wait 1us.
+	 */
+	udelay(1);
+
+	/* poll the bit becoming clear */
+	while ((readl(addr) & mask) && --timeout)
+		/* nothing */;
+
+	return !timeout;
+}
+
+#define MODULE_CLKGATE		(1 << 30)
+#define MODULE_SFTRST		(1 << 31)
+/*
+ * The current mxs_reset_block() will do two things:
+ *  [1] enable the module.
+ *  [2] reset the module.
+ *
+ * In most of the cases, it's ok. But there is a hardware bug in the BCH block.
+ * If you try to soft reset the BCH block, it becomes unusable until
+ * the next hard reset. This case occurs in the NAND boot mode. When the board
+ * boots by NAND, the ROM of the chip will initialize the BCH blocks itself.
+ * So If the driver tries to reset the BCH again, the BCH will not work anymore.
+ * You will see a DMA timeout in this case.
+ *
+ * To avoid this bug, just add a new parameter `just_enable` for
+ * the mxs_reset_block(), and rewrite it here.
+ */
+int gpmi_reset_block(void __iomem *reset_addr, bool just_enable)
+{
+	int ret;
+	int timeout = 0x400;
+
+	/* clear and poll SFTRST */
+	ret = clear_poll_bit(reset_addr, MODULE_SFTRST);
+	if (unlikely(ret))
+		goto error;
+
+	/* clear CLKGATE */
+	__mxs_clrl(MODULE_CLKGATE, reset_addr);
+
+	if (!just_enable) {
+		/* set SFTRST to reset the block */
+		__mxs_setl(MODULE_SFTRST, reset_addr);
+		udelay(1);
+
+		/* poll CLKGATE becoming set */
+		while ((!(readl(reset_addr) & MODULE_CLKGATE)) && --timeout)
+			/* nothing */;
+		if (unlikely(!timeout))
+			goto error;
+	}
+
+	/* clear and poll SFTRST */
+	ret = clear_poll_bit(reset_addr, MODULE_SFTRST);
+	if (unlikely(ret))
+		goto error;
+
+	/* clear and poll CLKGATE */
+	ret = clear_poll_bit(reset_addr, MODULE_CLKGATE);
+	if (unlikely(ret))
+		goto error;
+
+	return 0;
+
+error:
+	pr_err("%s(%p): module reset timeout\n", __func__, reset_addr);
+	return -ETIMEDOUT;
+}
+
+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 = gpmi_reset_block(r->gpmi_regs, false);
+	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 function is very useful. It is called only when the bug occur. */
+void gpmi_dump_info(struct gpmi_nand_data *this)
+{
+	struct resources *r = &this->resources;
+	struct bch_geometry *geo = &this->bch_geometry;
+	u32 reg;
+	int i;
+
+	pr_err("Show GPMI registers :\n");
+	for (i = 0; i <= HW_GPMI_DEBUG / 0x10 + 1; i++) {
+		reg = readl(r->gpmi_regs + i * 0x10);
+		pr_err("offset 0x%.3x : 0x%.8x\n", i * 0x10, reg);
+	}
+
+	/* start to print out the BCH info */
+	pr_err("BCH Geometry :\n");
+	pr_err("GF length              : %u\n", geo->gf_len);
+	pr_err("ECC Strength           : %u\n", geo->ecc_strength);
+	pr_err("Page Size in Bytes     : %u\n", geo->page_size);
+	pr_err("Metadata Size in Bytes : %u\n", geo->metadata_size);
+	pr_err("ECC Chunk Size in Bytes: %u\n", geo->ecc_chunk_size);
+	pr_err("ECC Chunk Count        : %u\n", geo->ecc_chunk_count);
+	pr_err("Payload Size in Bytes  : %u\n", geo->payload_size);
+	pr_err("Auxiliary Size in Bytes: %u\n", geo->auxiliary_size);
+	pr_err("Auxiliary Status Offset: %u\n", geo->auxiliary_status_offset);
+	pr_err("Block Mark Byte Offset : %u\n", geo->block_mark_byte_offset);
+	pr_err("Block Mark Bit Offset  : %u\n", geo->block_mark_bit_offset);
+}
+
+/* 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;
+	metadata_size = bch_geo->metadata_size;
+	ecc_strength  = bch_geo->ecc_strength >> 1;
+	page_size     = bch_geo->page_size;
+
+	ret = clk_enable(r->clock);
+	if (ret)
+		goto err_out;
+
+	ret = gpmi_reset_block(r->bch_regs, true);
+	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;
+}
+
+/* Converts time in nanoseconds to cycles. */
+static unsigned int ns_to_cycles(unsigned int time,
+			unsigned int period, unsigned int min)
+{
+	unsigned int k;
+
+	k = (time + period - 1) / period;
+	return max(k, min);
+}
+
+/* Apply timing to current hardware conditions. */
+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->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_err("We failed in enable the clk\n");
+		goto err_out;
+	}
+
+	/* set ready/busy timeout */
+	writel(0x500 << BP_GPMI_TIMING1_BUSY_TIMEOUT,
+		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);
+
+	/*
+	 * DLL_ENABLE must be set to 0 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 = 0;
+	uint32_t reg = 0;
+
+	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
+		pr_err("unknow arch.\n");
+	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 dma_async_tx_descriptor *desc;
+	struct scatterlist *sgl;
+	int chip = this->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(this->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_err("step 1 error\n");
+		return -1;
+	}
+
+	/* [2] send out the COMMAND + ADDRESS string stored in @buffer */
+	sgl = &this->cmd_sgl;
+
+	sg_init_one(sgl, this->cmd_buffer, this->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_err("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);
+	int chip = this->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(this->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_err("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, &this->data_sgl,
+						1, DMA_TO_DEVICE, 1);
+	if (!desc) {
+		pr_err("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);
+	int chip = this->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(this->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_err("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, &this->data_sgl,
+						1, DMA_FROM_DEVICE, 1);
+	if (!desc) {
+		pr_err("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);
+	int chip = this->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;
+	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_err("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);
+	int chip = this->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_err("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);
+
+	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;
+	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_err("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);
+	pio[1] = 0;
+	desc = channel->device->device_prep_slave_sg(channel,
+				(struct scatterlist *)pio, 2, DMA_NONE, 1);
+	if (!desc) {
+		pr_err("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 000000000000..83431240e2f2
--- /dev/null
+++ b/drivers/mtd/nand/gpmi-nand/gpmi-regs.h
@@ -0,0 +1,172 @@
+/*
+ * 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 BP_GPMI_TIMING1_BUSY_TIMEOUT			16
+
+#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