Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 3069 insertions, 0 deletions

diff --git a/drivers/mtd/nand/raw/qcom_nandc.c b/drivers/mtd/nand/raw/qcom_nandc.c
new file mode 100644
index 000000000..c64b408f0
--- /dev/null
+++ b/drivers/mtd/nand/raw/qcom_nandc.c
@@ -0,0 +1,3069 @@
+/*
+ * Copyright (c) 2016, The Linux Foundation. All rights reserved.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ */
+#include <linux/clk.h>
+#include <linux/slab.h>
+#include <linux/bitops.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmaengine.h>
+#include <linux/module.h>
+#include <linux/mtd/rawnand.h>
+#include <linux/mtd/partitions.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/delay.h>
+#include <linux/dma/qcom_bam_dma.h>
+
+/* NANDc reg offsets */
+#define	NAND_FLASH_CMD			0x00
+#define	NAND_ADDR0			0x04
+#define	NAND_ADDR1			0x08
+#define	NAND_FLASH_CHIP_SELECT		0x0c
+#define	NAND_EXEC_CMD			0x10
+#define	NAND_FLASH_STATUS		0x14
+#define	NAND_BUFFER_STATUS		0x18
+#define	NAND_DEV0_CFG0			0x20
+#define	NAND_DEV0_CFG1			0x24
+#define	NAND_DEV0_ECC_CFG		0x28
+#define	NAND_DEV1_ECC_CFG		0x2c
+#define	NAND_DEV1_CFG0			0x30
+#define	NAND_DEV1_CFG1			0x34
+#define	NAND_READ_ID			0x40
+#define	NAND_READ_STATUS		0x44
+#define	NAND_DEV_CMD0			0xa0
+#define	NAND_DEV_CMD1			0xa4
+#define	NAND_DEV_CMD2			0xa8
+#define	NAND_DEV_CMD_VLD		0xac
+#define	SFLASHC_BURST_CFG		0xe0
+#define	NAND_ERASED_CW_DETECT_CFG	0xe8
+#define	NAND_ERASED_CW_DETECT_STATUS	0xec
+#define	NAND_EBI2_ECC_BUF_CFG		0xf0
+#define	FLASH_BUF_ACC			0x100
+
+#define	NAND_CTRL			0xf00
+#define	NAND_VERSION			0xf08
+#define	NAND_READ_LOCATION_0		0xf20
+#define	NAND_READ_LOCATION_1		0xf24
+#define	NAND_READ_LOCATION_2		0xf28
+#define	NAND_READ_LOCATION_3		0xf2c
+
+/* dummy register offsets, used by write_reg_dma */
+#define	NAND_DEV_CMD1_RESTORE		0xdead
+#define	NAND_DEV_CMD_VLD_RESTORE	0xbeef
+
+/* NAND_FLASH_CMD bits */
+#define	PAGE_ACC			BIT(4)
+#define	LAST_PAGE			BIT(5)
+
+/* NAND_FLASH_CHIP_SELECT bits */
+#define	NAND_DEV_SEL			0
+#define	DM_EN				BIT(2)
+
+/* NAND_FLASH_STATUS bits */
+#define	FS_OP_ERR			BIT(4)
+#define	FS_READY_BSY_N			BIT(5)
+#define	FS_MPU_ERR			BIT(8)
+#define	FS_DEVICE_STS_ERR		BIT(16)
+#define	FS_DEVICE_WP			BIT(23)
+
+/* NAND_BUFFER_STATUS bits */
+#define	BS_UNCORRECTABLE_BIT		BIT(8)
+#define	BS_CORRECTABLE_ERR_MSK		0x1f
+
+/* NAND_DEVn_CFG0 bits */
+#define	DISABLE_STATUS_AFTER_WRITE	4
+#define	CW_PER_PAGE			6
+#define	UD_SIZE_BYTES			9
+#define	ECC_PARITY_SIZE_BYTES_RS	19
+#define	SPARE_SIZE_BYTES		23
+#define	NUM_ADDR_CYCLES			27
+#define	STATUS_BFR_READ			30
+#define	SET_RD_MODE_AFTER_STATUS	31
+
+/* NAND_DEVn_CFG0 bits */
+#define	DEV0_CFG1_ECC_DISABLE		0
+#define	WIDE_FLASH			1
+#define	NAND_RECOVERY_CYCLES		2
+#define	CS_ACTIVE_BSY			5
+#define	BAD_BLOCK_BYTE_NUM		6
+#define	BAD_BLOCK_IN_SPARE_AREA		16
+#define	WR_RD_BSY_GAP			17
+#define	ENABLE_BCH_ECC			27
+
+/* NAND_DEV0_ECC_CFG bits */
+#define	ECC_CFG_ECC_DISABLE		0
+#define	ECC_SW_RESET			1
+#define	ECC_MODE			4
+#define	ECC_PARITY_SIZE_BYTES_BCH	8
+#define	ECC_NUM_DATA_BYTES		16
+#define	ECC_FORCE_CLK_OPEN		30
+
+/* NAND_DEV_CMD1 bits */
+#define	READ_ADDR			0
+
+/* NAND_DEV_CMD_VLD bits */
+#define	READ_START_VLD			BIT(0)
+#define	READ_STOP_VLD			BIT(1)
+#define	WRITE_START_VLD			BIT(2)
+#define	ERASE_START_VLD			BIT(3)
+#define	SEQ_READ_START_VLD		BIT(4)
+
+/* NAND_EBI2_ECC_BUF_CFG bits */
+#define	NUM_STEPS			0
+
+/* NAND_ERASED_CW_DETECT_CFG bits */
+#define	ERASED_CW_ECC_MASK		1
+#define	AUTO_DETECT_RES			0
+#define	MASK_ECC			(1 << ERASED_CW_ECC_MASK)
+#define	RESET_ERASED_DET		(1 << AUTO_DETECT_RES)
+#define	ACTIVE_ERASED_DET		(0 << AUTO_DETECT_RES)
+#define	CLR_ERASED_PAGE_DET		(RESET_ERASED_DET | MASK_ECC)
+#define	SET_ERASED_PAGE_DET		(ACTIVE_ERASED_DET | MASK_ECC)
+
+/* NAND_ERASED_CW_DETECT_STATUS bits */
+#define	PAGE_ALL_ERASED			BIT(7)
+#define	CODEWORD_ALL_ERASED		BIT(6)
+#define	PAGE_ERASED			BIT(5)
+#define	CODEWORD_ERASED			BIT(4)
+#define	ERASED_PAGE			(PAGE_ALL_ERASED | PAGE_ERASED)
+#define	ERASED_CW			(CODEWORD_ALL_ERASED | CODEWORD_ERASED)
+
+/* NAND_READ_LOCATION_n bits */
+#define READ_LOCATION_OFFSET		0
+#define READ_LOCATION_SIZE		16
+#define READ_LOCATION_LAST		31
+
+/* Version Mask */
+#define	NAND_VERSION_MAJOR_MASK		0xf0000000
+#define	NAND_VERSION_MAJOR_SHIFT	28
+#define	NAND_VERSION_MINOR_MASK		0x0fff0000
+#define	NAND_VERSION_MINOR_SHIFT	16
+
+/* NAND OP_CMDs */
+#define	OP_PAGE_READ			0x2
+#define	OP_PAGE_READ_WITH_ECC		0x3
+#define	OP_PAGE_READ_WITH_ECC_SPARE	0x4
+#define	OP_PROGRAM_PAGE			0x6
+#define	OP_PAGE_PROGRAM_WITH_ECC	0x7
+#define	OP_PROGRAM_PAGE_SPARE		0x9
+#define	OP_BLOCK_ERASE			0xa
+#define	OP_FETCH_ID			0xb
+#define	OP_RESET_DEVICE			0xd
+
+/* Default Value for NAND_DEV_CMD_VLD */
+#define NAND_DEV_CMD_VLD_VAL		(READ_START_VLD | WRITE_START_VLD | \
+					 ERASE_START_VLD | SEQ_READ_START_VLD)
+
+/* NAND_CTRL bits */
+#define	BAM_MODE_EN			BIT(0)
+
+/*
+ * the NAND controller performs reads/writes with ECC in 516 byte chunks.
+ * the driver calls the chunks 'step' or 'codeword' interchangeably
+ */
+#define	NANDC_STEP_SIZE			512
+
+/*
+ * the largest page size we support is 8K, this will have 16 steps/codewords
+ * of 512 bytes each
+ */
+#define	MAX_NUM_STEPS			(SZ_8K / NANDC_STEP_SIZE)
+
+/* we read at most 3 registers per codeword scan */
+#define	MAX_REG_RD			(3 * MAX_NUM_STEPS)
+
+/* ECC modes supported by the controller */
+#define	ECC_NONE	BIT(0)
+#define	ECC_RS_4BIT	BIT(1)
+#define	ECC_BCH_4BIT	BIT(2)
+#define	ECC_BCH_8BIT	BIT(3)
+
+#define nandc_set_read_loc(nandc, reg, offset, size, is_last)	\
+nandc_set_reg(nandc, NAND_READ_LOCATION_##reg,			\
+	      ((offset) << READ_LOCATION_OFFSET) |		\
+	      ((size) << READ_LOCATION_SIZE) |			\
+	      ((is_last) << READ_LOCATION_LAST))
+
+/*
+ * Returns the actual register address for all NAND_DEV_ registers
+ * (i.e. NAND_DEV_CMD0, NAND_DEV_CMD1, NAND_DEV_CMD2 and NAND_DEV_CMD_VLD)
+ */
+#define dev_cmd_reg_addr(nandc, reg) ((nandc)->props->dev_cmd_reg_start + (reg))
+
+/* Returns the NAND register physical address */
+#define nandc_reg_phys(chip, offset) ((chip)->base_phys + (offset))
+
+/* Returns the dma address for reg read buffer */
+#define reg_buf_dma_addr(chip, vaddr) \
+	((chip)->reg_read_dma + \
+	((uint8_t *)(vaddr) - (uint8_t *)(chip)->reg_read_buf))
+
+#define QPIC_PER_CW_CMD_ELEMENTS	32
+#define QPIC_PER_CW_CMD_SGL		32
+#define QPIC_PER_CW_DATA_SGL		8
+
+#define QPIC_NAND_COMPLETION_TIMEOUT	msecs_to_jiffies(2000)
+
+/*
+ * Flags used in DMA descriptor preparation helper functions
+ * (i.e. read_reg_dma/write_reg_dma/read_data_dma/write_data_dma)
+ */
+/* Don't set the EOT in current tx BAM sgl */
+#define NAND_BAM_NO_EOT			BIT(0)
+/* Set the NWD flag in current BAM sgl */
+#define NAND_BAM_NWD			BIT(1)
+/* Finish writing in the current BAM sgl and start writing in another BAM sgl */
+#define NAND_BAM_NEXT_SGL		BIT(2)
+/*
+ * Erased codeword status is being used two times in single transfer so this
+ * flag will determine the current value of erased codeword status register
+ */
+#define NAND_ERASED_CW_SET		BIT(4)
+
+/*
+ * This data type corresponds to the BAM transaction which will be used for all
+ * NAND transfers.
+ * @bam_ce - the array of BAM command elements
+ * @cmd_sgl - sgl for NAND BAM command pipe
+ * @data_sgl - sgl for NAND BAM consumer/producer pipe
+ * @bam_ce_pos - the index in bam_ce which is available for next sgl
+ * @bam_ce_start - the index in bam_ce which marks the start position ce
+ *		   for current sgl. It will be used for size calculation
+ *		   for current sgl
+ * @cmd_sgl_pos - current index in command sgl.
+ * @cmd_sgl_start - start index in command sgl.
+ * @tx_sgl_pos - current index in data sgl for tx.
+ * @tx_sgl_start - start index in data sgl for tx.
+ * @rx_sgl_pos - current index in data sgl for rx.
+ * @rx_sgl_start - start index in data sgl for rx.
+ * @wait_second_completion - wait for second DMA desc completion before making
+ *			     the NAND transfer completion.
+ * @txn_done - completion for NAND transfer.
+ * @last_data_desc - last DMA desc in data channel (tx/rx).
+ * @last_cmd_desc - last DMA desc in command channel.
+ */
+struct bam_transaction {
+	struct bam_cmd_element *bam_ce;
+	struct scatterlist *cmd_sgl;
+	struct scatterlist *data_sgl;
+	u32 bam_ce_pos;
+	u32 bam_ce_start;
+	u32 cmd_sgl_pos;
+	u32 cmd_sgl_start;
+	u32 tx_sgl_pos;
+	u32 tx_sgl_start;
+	u32 rx_sgl_pos;
+	u32 rx_sgl_start;
+	bool wait_second_completion;
+	struct completion txn_done;
+	struct dma_async_tx_descriptor *last_data_desc;
+	struct dma_async_tx_descriptor *last_cmd_desc;
+};
+
+/*
+ * This data type corresponds to the nand dma descriptor
+ * @list - list for desc_info
+ * @dir - DMA transfer direction
+ * @adm_sgl - sgl which will be used for single sgl dma descriptor. Only used by
+ *	      ADM
+ * @bam_sgl - sgl which will be used for dma descriptor. Only used by BAM
+ * @sgl_cnt - number of SGL in bam_sgl. Only used by BAM
+ * @dma_desc - low level DMA engine descriptor
+ */
+struct desc_info {
+	struct list_head node;
+
+	enum dma_data_direction dir;
+	union {
+		struct scatterlist adm_sgl;
+		struct {
+			struct scatterlist *bam_sgl;
+			int sgl_cnt;
+		};
+	};
+	struct dma_async_tx_descriptor *dma_desc;
+};
+
+/*
+ * holds the current register values that we want to write. acts as a contiguous
+ * chunk of memory which we use to write the controller registers through DMA.
+ */
+struct nandc_regs {
+	__le32 cmd;
+	__le32 addr0;
+	__le32 addr1;
+	__le32 chip_sel;
+	__le32 exec;
+
+	__le32 cfg0;
+	__le32 cfg1;
+	__le32 ecc_bch_cfg;
+
+	__le32 clrflashstatus;
+	__le32 clrreadstatus;
+
+	__le32 cmd1;
+	__le32 vld;
+
+	__le32 orig_cmd1;
+	__le32 orig_vld;
+
+	__le32 ecc_buf_cfg;
+	__le32 read_location0;
+	__le32 read_location1;
+	__le32 read_location2;
+	__le32 read_location3;
+
+	__le32 erased_cw_detect_cfg_clr;
+	__le32 erased_cw_detect_cfg_set;
+};
+
+/*
+ * NAND controller data struct
+ *
+ * @controller:			base controller structure
+ * @host_list:			list containing all the chips attached to the
+ *				controller
+ * @dev:			parent device
+ * @base:			MMIO base
+ * @base_phys:			physical base address of controller registers
+ * @base_dma:			dma base address of controller registers
+ * @core_clk:			controller clock
+ * @aon_clk:			another controller clock
+ *
+ * @chan:			dma channel
+ * @cmd_crci:			ADM DMA CRCI for command flow control
+ * @data_crci:			ADM DMA CRCI for data flow control
+ * @desc_list:			DMA descriptor list (list of desc_infos)
+ *
+ * @data_buffer:		our local DMA buffer for page read/writes,
+ *				used when we can't use the buffer provided
+ *				by upper layers directly
+ * @buf_size/count/start:	markers for chip->read_buf/write_buf functions
+ * @reg_read_buf:		local buffer for reading back registers via DMA
+ * @reg_read_dma:		contains dma address for register read buffer
+ * @reg_read_pos:		marker for data read in reg_read_buf
+ *
+ * @regs:			a contiguous chunk of memory for DMA register
+ *				writes. contains the register values to be
+ *				written to controller
+ * @cmd1/vld:			some fixed controller register values
+ * @props:			properties of current NAND controller,
+ *				initialized via DT match data
+ * @max_cwperpage:		maximum QPIC codewords required. calculated
+ *				from all connected NAND devices pagesize
+ */
+struct qcom_nand_controller {
+	struct nand_controller controller;
+	struct list_head host_list;
+
+	struct device *dev;
+
+	void __iomem *base;
+	phys_addr_t base_phys;
+	dma_addr_t base_dma;
+
+	struct clk *core_clk;
+	struct clk *aon_clk;
+
+	union {
+		/* will be used only by QPIC for BAM DMA */
+		struct {
+			struct dma_chan *tx_chan;
+			struct dma_chan *rx_chan;
+			struct dma_chan *cmd_chan;
+		};
+
+		/* will be used only by EBI2 for ADM DMA */
+		struct {
+			struct dma_chan *chan;
+			unsigned int cmd_crci;
+			unsigned int data_crci;
+		};
+	};
+
+	struct list_head desc_list;
+	struct bam_transaction *bam_txn;
+
+	u8		*data_buffer;
+	int		buf_size;
+	int		buf_count;
+	int		buf_start;
+	unsigned int	max_cwperpage;
+
+	__le32 *reg_read_buf;
+	dma_addr_t reg_read_dma;
+	int reg_read_pos;
+
+	struct nandc_regs *regs;
+
+	u32 cmd1, vld;
+	const struct qcom_nandc_props *props;
+};
+
+/*
+ * NAND chip structure
+ *
+ * @chip:			base NAND chip structure
+ * @node:			list node to add itself to host_list in
+ *				qcom_nand_controller
+ *
+ * @cs:				chip select value for this chip
+ * @cw_size:			the number of bytes in a single step/codeword
+ *				of a page, consisting of all data, ecc, spare
+ *				and reserved bytes
+ * @cw_data:			the number of bytes within a codeword protected
+ *				by ECC
+ * @use_ecc:			request the controller to use ECC for the
+ *				upcoming read/write
+ * @bch_enabled:		flag to tell whether BCH ECC mode is used
+ * @ecc_bytes_hw:		ECC bytes used by controller hardware for this
+ *				chip
+ * @status:			value to be returned if NAND_CMD_STATUS command
+ *				is executed
+ * @last_command:		keeps track of last command on this chip. used
+ *				for reading correct status
+ *
+ * @cfg0, cfg1, cfg0_raw..:	NANDc register configurations needed for
+ *				ecc/non-ecc mode for the current nand flash
+ *				device
+ */
+struct qcom_nand_host {
+	struct nand_chip chip;
+	struct list_head node;
+
+	int cs;
+	int cw_size;
+	int cw_data;
+	bool use_ecc;
+	bool bch_enabled;
+	int ecc_bytes_hw;
+	int spare_bytes;
+	int bbm_size;
+	u8 status;
+	int last_command;
+
+	u32 cfg0, cfg1;
+	u32 cfg0_raw, cfg1_raw;
+	u32 ecc_buf_cfg;
+	u32 ecc_bch_cfg;
+	u32 clrflashstatus;
+	u32 clrreadstatus;
+};
+
+/*
+ * This data type corresponds to the NAND controller properties which varies
+ * among different NAND controllers.
+ * @ecc_modes - ecc mode for NAND
+ * @is_bam - whether NAND controller is using BAM
+ * @is_qpic - whether NAND CTRL is part of qpic IP
+ * @dev_cmd_reg_start - NAND_DEV_CMD_* registers starting offset
+ */
+struct qcom_nandc_props {
+	u32 ecc_modes;
+	bool is_bam;
+	bool is_qpic;
+	u32 dev_cmd_reg_start;
+};
+
+/* Frees the BAM transaction memory */
+static void free_bam_transaction(struct qcom_nand_controller *nandc)
+{
+	struct bam_transaction *bam_txn = nandc->bam_txn;
+
+	devm_kfree(nandc->dev, bam_txn);
+}
+
+/* Allocates and Initializes the BAM transaction */
+static struct bam_transaction *
+alloc_bam_transaction(struct qcom_nand_controller *nandc)
+{
+	struct bam_transaction *bam_txn;
+	size_t bam_txn_size;
+	unsigned int num_cw = nandc->max_cwperpage;
+	void *bam_txn_buf;
+
+	bam_txn_size =
+		sizeof(*bam_txn) + num_cw *
+		((sizeof(*bam_txn->bam_ce) * QPIC_PER_CW_CMD_ELEMENTS) +
+		(sizeof(*bam_txn->cmd_sgl) * QPIC_PER_CW_CMD_SGL) +
+		(sizeof(*bam_txn->data_sgl) * QPIC_PER_CW_DATA_SGL));
+
+	bam_txn_buf = devm_kzalloc(nandc->dev, bam_txn_size, GFP_KERNEL);
+	if (!bam_txn_buf)
+		return NULL;
+
+	bam_txn = bam_txn_buf;
+	bam_txn_buf += sizeof(*bam_txn);
+
+	bam_txn->bam_ce = bam_txn_buf;
+	bam_txn_buf +=
+		sizeof(*bam_txn->bam_ce) * QPIC_PER_CW_CMD_ELEMENTS * num_cw;
+
+	bam_txn->cmd_sgl = bam_txn_buf;
+	bam_txn_buf +=
+		sizeof(*bam_txn->cmd_sgl) * QPIC_PER_CW_CMD_SGL * num_cw;
+
+	bam_txn->data_sgl = bam_txn_buf;
+
+	init_completion(&bam_txn->txn_done);
+
+	return bam_txn;
+}
+
+/* Clears the BAM transaction indexes */
+static void clear_bam_transaction(struct qcom_nand_controller *nandc)
+{
+	struct bam_transaction *bam_txn = nandc->bam_txn;
+
+	if (!nandc->props->is_bam)
+		return;
+
+	bam_txn->bam_ce_pos = 0;
+	bam_txn->bam_ce_start = 0;
+	bam_txn->cmd_sgl_pos = 0;
+	bam_txn->cmd_sgl_start = 0;
+	bam_txn->tx_sgl_pos = 0;
+	bam_txn->tx_sgl_start = 0;
+	bam_txn->rx_sgl_pos = 0;
+	bam_txn->rx_sgl_start = 0;
+	bam_txn->last_data_desc = NULL;
+	bam_txn->wait_second_completion = false;
+
+	sg_init_table(bam_txn->cmd_sgl, nandc->max_cwperpage *
+		      QPIC_PER_CW_CMD_SGL);
+	sg_init_table(bam_txn->data_sgl, nandc->max_cwperpage *
+		      QPIC_PER_CW_DATA_SGL);
+
+	reinit_completion(&bam_txn->txn_done);
+}
+
+/* Callback for DMA descriptor completion */
+static void qpic_bam_dma_done(void *data)
+{
+	struct bam_transaction *bam_txn = data;
+
+	/*
+	 * In case of data transfer with NAND, 2 callbacks will be generated.
+	 * One for command channel and another one for data channel.
+	 * If current transaction has data descriptors
+	 * (i.e. wait_second_completion is true), then set this to false
+	 * and wait for second DMA descriptor completion.
+	 */
+	if (bam_txn->wait_second_completion)
+		bam_txn->wait_second_completion = false;
+	else
+		complete(&bam_txn->txn_done);
+}
+
+static inline struct qcom_nand_host *to_qcom_nand_host(struct nand_chip *chip)
+{
+	return container_of(chip, struct qcom_nand_host, chip);
+}
+
+static inline struct qcom_nand_controller *
+get_qcom_nand_controller(struct nand_chip *chip)
+{
+	return container_of(chip->controller, struct qcom_nand_controller,
+			    controller);
+}
+
+static inline u32 nandc_read(struct qcom_nand_controller *nandc, int offset)
+{
+	return ioread32(nandc->base + offset);
+}
+
+static inline void nandc_write(struct qcom_nand_controller *nandc, int offset,
+			       u32 val)
+{
+	iowrite32(val, nandc->base + offset);
+}
+
+static inline void nandc_read_buffer_sync(struct qcom_nand_controller *nandc,
+					  bool is_cpu)
+{
+	if (!nandc->props->is_bam)
+		return;
+
+	if (is_cpu)
+		dma_sync_single_for_cpu(nandc->dev, nandc->reg_read_dma,
+					MAX_REG_RD *
+					sizeof(*nandc->reg_read_buf),
+					DMA_FROM_DEVICE);
+	else
+		dma_sync_single_for_device(nandc->dev, nandc->reg_read_dma,
+					   MAX_REG_RD *
+					   sizeof(*nandc->reg_read_buf),
+					   DMA_FROM_DEVICE);
+}
+
+static __le32 *offset_to_nandc_reg(struct nandc_regs *regs, int offset)
+{
+	switch (offset) {
+	case NAND_FLASH_CMD:
+		return &regs->cmd;
+	case NAND_ADDR0:
+		return &regs->addr0;
+	case NAND_ADDR1:
+		return &regs->addr1;
+	case NAND_FLASH_CHIP_SELECT:
+		return &regs->chip_sel;
+	case NAND_EXEC_CMD:
+		return &regs->exec;
+	case NAND_FLASH_STATUS:
+		return &regs->clrflashstatus;
+	case NAND_DEV0_CFG0:
+		return &regs->cfg0;
+	case NAND_DEV0_CFG1:
+		return &regs->cfg1;
+	case NAND_DEV0_ECC_CFG:
+		return &regs->ecc_bch_cfg;
+	case NAND_READ_STATUS:
+		return &regs->clrreadstatus;
+	case NAND_DEV_CMD1:
+		return &regs->cmd1;
+	case NAND_DEV_CMD1_RESTORE:
+		return &regs->orig_cmd1;
+	case NAND_DEV_CMD_VLD:
+		return &regs->vld;
+	case NAND_DEV_CMD_VLD_RESTORE:
+		return &regs->orig_vld;
+	case NAND_EBI2_ECC_BUF_CFG:
+		return &regs->ecc_buf_cfg;
+	case NAND_READ_LOCATION_0:
+		return &regs->read_location0;
+	case NAND_READ_LOCATION_1:
+		return &regs->read_location1;
+	case NAND_READ_LOCATION_2:
+		return &regs->read_location2;
+	case NAND_READ_LOCATION_3:
+		return &regs->read_location3;
+	default:
+		return NULL;
+	}
+}
+
+static void nandc_set_reg(struct qcom_nand_controller *nandc, int offset,
+			  u32 val)
+{
+	struct nandc_regs *regs = nandc->regs;
+	__le32 *reg;
+
+	reg = offset_to_nandc_reg(regs, offset);
+
+	if (reg)
+		*reg = cpu_to_le32(val);
+}
+
+/* helper to configure address register values */
+static void set_address(struct qcom_nand_host *host, u16 column, int page)
+{
+	struct nand_chip *chip = &host->chip;
+	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+
+	if (chip->options & NAND_BUSWIDTH_16)
+		column >>= 1;
+
+	nandc_set_reg(nandc, NAND_ADDR0, page << 16 | column);
+	nandc_set_reg(nandc, NAND_ADDR1, page >> 16 & 0xff);
+}
+
+/*
+ * update_rw_regs:	set up read/write register values, these will be
+ *			written to the NAND controller registers via DMA
+ *
+ * @num_cw:		number of steps for the read/write operation
+ * @read:		read or write operation
+ */
+static void update_rw_regs(struct qcom_nand_host *host, int num_cw, bool read)
+{
+	struct nand_chip *chip = &host->chip;
+	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+	u32 cmd, cfg0, cfg1, ecc_bch_cfg;
+
+	if (read) {
+		if (host->use_ecc)
+			cmd = OP_PAGE_READ_WITH_ECC | PAGE_ACC | LAST_PAGE;
+		else
+			cmd = OP_PAGE_READ | PAGE_ACC | LAST_PAGE;
+	} else {
+		cmd = OP_PROGRAM_PAGE | PAGE_ACC | LAST_PAGE;
+	}
+
+	if (host->use_ecc) {
+		cfg0 = (host->cfg0 & ~(7U << CW_PER_PAGE)) |
+				(num_cw - 1) << CW_PER_PAGE;
+
+		cfg1 = host->cfg1;
+		ecc_bch_cfg = host->ecc_bch_cfg;
+	} else {
+		cfg0 = (host->cfg0_raw & ~(7U << CW_PER_PAGE)) |
+				(num_cw - 1) << CW_PER_PAGE;
+
+		cfg1 = host->cfg1_raw;
+		ecc_bch_cfg = 1 << ECC_CFG_ECC_DISABLE;
+	}
+
+	nandc_set_reg(nandc, NAND_FLASH_CMD, cmd);
+	nandc_set_reg(nandc, NAND_DEV0_CFG0, cfg0);
+	nandc_set_reg(nandc, NAND_DEV0_CFG1, cfg1);
+	nandc_set_reg(nandc, NAND_DEV0_ECC_CFG, ecc_bch_cfg);
+	nandc_set_reg(nandc, NAND_EBI2_ECC_BUF_CFG, host->ecc_buf_cfg);
+	nandc_set_reg(nandc, NAND_FLASH_STATUS, host->clrflashstatus);
+	nandc_set_reg(nandc, NAND_READ_STATUS, host->clrreadstatus);
+	nandc_set_reg(nandc, NAND_EXEC_CMD, 1);
+
+	if (read)
+		nandc_set_read_loc(nandc, 0, 0, host->use_ecc ?
+				   host->cw_data : host->cw_size, 1);
+}
+
+/*
+ * Maps the scatter gather list for DMA transfer and forms the DMA descriptor
+ * for BAM. This descriptor will be added in the NAND DMA descriptor queue
+ * which will be submitted to DMA engine.
+ */
+static int prepare_bam_async_desc(struct qcom_nand_controller *nandc,
+				  struct dma_chan *chan,
+				  unsigned long flags)
+{
+	struct desc_info *desc;
+	struct scatterlist *sgl;
+	unsigned int sgl_cnt;
+	int ret;
+	struct bam_transaction *bam_txn = nandc->bam_txn;
+	enum dma_transfer_direction dir_eng;
+	struct dma_async_tx_descriptor *dma_desc;
+
+	desc = kzalloc(sizeof(*desc), GFP_KERNEL);
+	if (!desc)
+		return -ENOMEM;
+
+	if (chan == nandc->cmd_chan) {
+		sgl = &bam_txn->cmd_sgl[bam_txn->cmd_sgl_start];
+		sgl_cnt = bam_txn->cmd_sgl_pos - bam_txn->cmd_sgl_start;
+		bam_txn->cmd_sgl_start = bam_txn->cmd_sgl_pos;
+		dir_eng = DMA_MEM_TO_DEV;
+		desc->dir = DMA_TO_DEVICE;
+	} else if (chan == nandc->tx_chan) {
+		sgl = &bam_txn->data_sgl[bam_txn->tx_sgl_start];
+		sgl_cnt = bam_txn->tx_sgl_pos - bam_txn->tx_sgl_start;
+		bam_txn->tx_sgl_start = bam_txn->tx_sgl_pos;
+		dir_eng = DMA_MEM_TO_DEV;
+		desc->dir = DMA_TO_DEVICE;
+	} else {
+		sgl = &bam_txn->data_sgl[bam_txn->rx_sgl_start];
+		sgl_cnt = bam_txn->rx_sgl_pos - bam_txn->rx_sgl_start;
+		bam_txn->rx_sgl_start = bam_txn->rx_sgl_pos;
+		dir_eng = DMA_DEV_TO_MEM;
+		desc->dir = DMA_FROM_DEVICE;
+	}
+
+	sg_mark_end(sgl + sgl_cnt - 1);
+	ret = dma_map_sg(nandc->dev, sgl, sgl_cnt, desc->dir);
+	if (ret == 0) {
+		dev_err(nandc->dev, "failure in mapping desc\n");
+		kfree(desc);
+		return -ENOMEM;
+	}
+
+	desc->sgl_cnt = sgl_cnt;
+	desc->bam_sgl = sgl;
+
+	dma_desc = dmaengine_prep_slave_sg(chan, sgl, sgl_cnt, dir_eng,
+					   flags);
+
+	if (!dma_desc) {
+		dev_err(nandc->dev, "failure in prep desc\n");
+		dma_unmap_sg(nandc->dev, sgl, sgl_cnt, desc->dir);
+		kfree(desc);
+		return -EINVAL;
+	}
+
+	desc->dma_desc = dma_desc;
+
+	/* update last data/command descriptor */
+	if (chan == nandc->cmd_chan)
+		bam_txn->last_cmd_desc = dma_desc;
+	else
+		bam_txn->last_data_desc = dma_desc;
+
+	list_add_tail(&desc->node, &nandc->desc_list);
+
+	return 0;
+}
+
+/*
+ * Prepares the command descriptor for BAM DMA which will be used for NAND
+ * register reads and writes. The command descriptor requires the command
+ * to be formed in command element type so this function uses the command
+ * element from bam transaction ce array and fills the same with required
+ * data. A single SGL can contain multiple command elements so
+ * NAND_BAM_NEXT_SGL will be used for starting the separate SGL
+ * after the current command element.
+ */
+static int prep_bam_dma_desc_cmd(struct qcom_nand_controller *nandc, bool read,
+				 int reg_off, const void *vaddr,
+				 int size, unsigned int flags)
+{
+	int bam_ce_size;
+	int i, ret;
+	struct bam_cmd_element *bam_ce_buffer;
+	struct bam_transaction *bam_txn = nandc->bam_txn;
+
+	bam_ce_buffer = &bam_txn->bam_ce[bam_txn->bam_ce_pos];
+
+	/* fill the command desc */
+	for (i = 0; i < size; i++) {
+		if (read)
+			bam_prep_ce(&bam_ce_buffer[i],
+				    nandc_reg_phys(nandc, reg_off + 4 * i),
+				    BAM_READ_COMMAND,
+				    reg_buf_dma_addr(nandc,
+						     (__le32 *)vaddr + i));
+		else
+			bam_prep_ce_le32(&bam_ce_buffer[i],
+					 nandc_reg_phys(nandc, reg_off + 4 * i),
+					 BAM_WRITE_COMMAND,
+					 *((__le32 *)vaddr + i));
+	}
+
+	bam_txn->bam_ce_pos += size;
+
+	/* use the separate sgl after this command */
+	if (flags & NAND_BAM_NEXT_SGL) {
+		bam_ce_buffer = &bam_txn->bam_ce[bam_txn->bam_ce_start];
+		bam_ce_size = (bam_txn->bam_ce_pos -
+				bam_txn->bam_ce_start) *
+				sizeof(struct bam_cmd_element);
+		sg_set_buf(&bam_txn->cmd_sgl[bam_txn->cmd_sgl_pos],
+			   bam_ce_buffer, bam_ce_size);
+		bam_txn->cmd_sgl_pos++;
+		bam_txn->bam_ce_start = bam_txn->bam_ce_pos;
+
+		if (flags & NAND_BAM_NWD) {
+			ret = prepare_bam_async_desc(nandc, nandc->cmd_chan,
+						     DMA_PREP_FENCE |
+						     DMA_PREP_CMD);
+			if (ret)
+				return ret;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Prepares the data descriptor for BAM DMA which will be used for NAND
+ * data reads and writes.
+ */
+static int prep_bam_dma_desc_data(struct qcom_nand_controller *nandc, bool read,
+				  const void *vaddr,
+				  int size, unsigned int flags)
+{
+	int ret;
+	struct bam_transaction *bam_txn = nandc->bam_txn;
+
+	if (read) {
+		sg_set_buf(&bam_txn->data_sgl[bam_txn->rx_sgl_pos],
+			   vaddr, size);
+		bam_txn->rx_sgl_pos++;
+	} else {
+		sg_set_buf(&bam_txn->data_sgl[bam_txn->tx_sgl_pos],
+			   vaddr, size);
+		bam_txn->tx_sgl_pos++;
+
+		/*
+		 * BAM will only set EOT for DMA_PREP_INTERRUPT so if this flag
+		 * is not set, form the DMA descriptor
+		 */
+		if (!(flags & NAND_BAM_NO_EOT)) {
+			ret = prepare_bam_async_desc(nandc, nandc->tx_chan,
+						     DMA_PREP_INTERRUPT);
+			if (ret)
+				return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int prep_adm_dma_desc(struct qcom_nand_controller *nandc, bool read,
+			     int reg_off, const void *vaddr, int size,
+			     bool flow_control)
+{
+	struct desc_info *desc;
+	struct dma_async_tx_descriptor *dma_desc;
+	struct scatterlist *sgl;
+	struct dma_slave_config slave_conf;
+	enum dma_transfer_direction dir_eng;
+	int ret;
+
+	desc = kzalloc(sizeof(*desc), GFP_KERNEL);
+	if (!desc)
+		return -ENOMEM;
+
+	sgl = &desc->adm_sgl;
+
+	sg_init_one(sgl, vaddr, size);
+
+	if (read) {
+		dir_eng = DMA_DEV_TO_MEM;
+		desc->dir = DMA_FROM_DEVICE;
+	} else {
+		dir_eng = DMA_MEM_TO_DEV;
+		desc->dir = DMA_TO_DEVICE;
+	}
+
+	ret = dma_map_sg(nandc->dev, sgl, 1, desc->dir);
+	if (ret == 0) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	memset(&slave_conf, 0x00, sizeof(slave_conf));
+
+	slave_conf.device_fc = flow_control;
+	if (read) {
+		slave_conf.src_maxburst = 16;
+		slave_conf.src_addr = nandc->base_dma + reg_off;
+		slave_conf.slave_id = nandc->data_crci;
+	} else {
+		slave_conf.dst_maxburst = 16;
+		slave_conf.dst_addr = nandc->base_dma + reg_off;
+		slave_conf.slave_id = nandc->cmd_crci;
+	}
+
+	ret = dmaengine_slave_config(nandc->chan, &slave_conf);
+	if (ret) {
+		dev_err(nandc->dev, "failed to configure dma channel\n");
+		goto err;
+	}
+
+	dma_desc = dmaengine_prep_slave_sg(nandc->chan, sgl, 1, dir_eng, 0);
+	if (!dma_desc) {
+		dev_err(nandc->dev, "failed to prepare desc\n");
+		ret = -EINVAL;
+		goto err;
+	}
+
+	desc->dma_desc = dma_desc;
+
+	list_add_tail(&desc->node, &nandc->desc_list);
+
+	return 0;
+err:
+	kfree(desc);
+
+	return ret;
+}
+
+/*
+ * read_reg_dma:	prepares a descriptor to read a given number of
+ *			contiguous registers to the reg_read_buf pointer
+ *
+ * @first:		offset of the first register in the contiguous block
+ * @num_regs:		number of registers to read
+ * @flags:		flags to control DMA descriptor preparation
+ */
+static int read_reg_dma(struct qcom_nand_controller *nandc, int first,
+			int num_regs, unsigned int flags)
+{
+	bool flow_control = false;
+	void *vaddr;
+
+	vaddr = nandc->reg_read_buf + nandc->reg_read_pos;
+	nandc->reg_read_pos += num_regs;
+
+	if (first == NAND_DEV_CMD_VLD || first == NAND_DEV_CMD1)
+		first = dev_cmd_reg_addr(nandc, first);
+
+	if (nandc->props->is_bam)
+		return prep_bam_dma_desc_cmd(nandc, true, first, vaddr,
+					     num_regs, flags);
+
+	if (first == NAND_READ_ID || first == NAND_FLASH_STATUS)
+		flow_control = true;
+
+	return prep_adm_dma_desc(nandc, true, first, vaddr,
+				 num_regs * sizeof(u32), flow_control);
+}
+
+/*
+ * write_reg_dma:	prepares a descriptor to write a given number of
+ *			contiguous registers
+ *
+ * @first:		offset of the first register in the contiguous block
+ * @num_regs:		number of registers to write
+ * @flags:		flags to control DMA descriptor preparation
+ */
+static int write_reg_dma(struct qcom_nand_controller *nandc, int first,
+			 int num_regs, unsigned int flags)
+{
+	bool flow_control = false;
+	struct nandc_regs *regs = nandc->regs;
+	void *vaddr;
+
+	vaddr = offset_to_nandc_reg(regs, first);
+
+	if (first == NAND_ERASED_CW_DETECT_CFG) {
+		if (flags & NAND_ERASED_CW_SET)
+			vaddr = &regs->erased_cw_detect_cfg_set;
+		else
+			vaddr = &regs->erased_cw_detect_cfg_clr;
+	}
+
+	if (first == NAND_EXEC_CMD)
+		flags |= NAND_BAM_NWD;
+
+	if (first == NAND_DEV_CMD1_RESTORE || first == NAND_DEV_CMD1)
+		first = dev_cmd_reg_addr(nandc, NAND_DEV_CMD1);
+
+	if (first == NAND_DEV_CMD_VLD_RESTORE || first == NAND_DEV_CMD_VLD)
+		first = dev_cmd_reg_addr(nandc, NAND_DEV_CMD_VLD);
+
+	if (nandc->props->is_bam)
+		return prep_bam_dma_desc_cmd(nandc, false, first, vaddr,
+					     num_regs, flags);
+
+	if (first == NAND_FLASH_CMD)
+		flow_control = true;
+
+	return prep_adm_dma_desc(nandc, false, first, vaddr,
+				 num_regs * sizeof(u32), flow_control);
+}
+
+/*
+ * read_data_dma:	prepares a DMA descriptor to transfer data from the
+ *			controller's internal buffer to the buffer 'vaddr'
+ *
+ * @reg_off:		offset within the controller's data buffer
+ * @vaddr:		virtual address of the buffer we want to write to
+ * @size:		DMA transaction size in bytes
+ * @flags:		flags to control DMA descriptor preparation
+ */
+static int read_data_dma(struct qcom_nand_controller *nandc, int reg_off,
+			 const u8 *vaddr, int size, unsigned int flags)
+{
+	if (nandc->props->is_bam)
+		return prep_bam_dma_desc_data(nandc, true, vaddr, size, flags);
+
+	return prep_adm_dma_desc(nandc, true, reg_off, vaddr, size, false);
+}
+
+/*
+ * write_data_dma:	prepares a DMA descriptor to transfer data from
+ *			'vaddr' to the controller's internal buffer
+ *
+ * @reg_off:		offset within the controller's data buffer
+ * @vaddr:		virtual address of the buffer we want to read from
+ * @size:		DMA transaction size in bytes
+ * @flags:		flags to control DMA descriptor preparation
+ */
+static int write_data_dma(struct qcom_nand_controller *nandc, int reg_off,
+			  const u8 *vaddr, int size, unsigned int flags)
+{
+	if (nandc->props->is_bam)
+		return prep_bam_dma_desc_data(nandc, false, vaddr, size, flags);
+
+	return prep_adm_dma_desc(nandc, false, reg_off, vaddr, size, false);
+}
+
+/*
+ * Helper to prepare DMA descriptors for configuring registers
+ * before reading a NAND page.
+ */
+static void config_nand_page_read(struct qcom_nand_controller *nandc)
+{
+	write_reg_dma(nandc, NAND_ADDR0, 2, 0);
+	write_reg_dma(nandc, NAND_DEV0_CFG0, 3, 0);
+	write_reg_dma(nandc, NAND_EBI2_ECC_BUF_CFG, 1, 0);
+	write_reg_dma(nandc, NAND_ERASED_CW_DETECT_CFG, 1, 0);
+	write_reg_dma(nandc, NAND_ERASED_CW_DETECT_CFG, 1,
+		      NAND_ERASED_CW_SET | NAND_BAM_NEXT_SGL);
+}
+
+/*
+ * Helper to prepare DMA descriptors for configuring registers
+ * before reading each codeword in NAND page.
+ */
+static void
+config_nand_cw_read(struct qcom_nand_controller *nandc, bool use_ecc)
+{
+	if (nandc->props->is_bam)
+		write_reg_dma(nandc, NAND_READ_LOCATION_0, 4,
+			      NAND_BAM_NEXT_SGL);
+
+	write_reg_dma(nandc, NAND_FLASH_CMD, 1, NAND_BAM_NEXT_SGL);
+	write_reg_dma(nandc, NAND_EXEC_CMD, 1, NAND_BAM_NEXT_SGL);
+
+	if (use_ecc) {
+		read_reg_dma(nandc, NAND_FLASH_STATUS, 2, 0);
+		read_reg_dma(nandc, NAND_ERASED_CW_DETECT_STATUS, 1,
+			     NAND_BAM_NEXT_SGL);
+	} else {
+		read_reg_dma(nandc, NAND_FLASH_STATUS, 1, NAND_BAM_NEXT_SGL);
+	}
+}
+
+/*
+ * Helper to prepare dma descriptors to configure registers needed for reading a
+ * single codeword in page
+ */
+static void
+config_nand_single_cw_page_read(struct qcom_nand_controller *nandc,
+				bool use_ecc)
+{
+	config_nand_page_read(nandc);
+	config_nand_cw_read(nandc, use_ecc);
+}
+
+/*
+ * Helper to prepare DMA descriptors used to configure registers needed for
+ * before writing a NAND page.
+ */
+static void config_nand_page_write(struct qcom_nand_controller *nandc)
+{
+	write_reg_dma(nandc, NAND_ADDR0, 2, 0);
+	write_reg_dma(nandc, NAND_DEV0_CFG0, 3, 0);
+	write_reg_dma(nandc, NAND_EBI2_ECC_BUF_CFG, 1,
+		      NAND_BAM_NEXT_SGL);
+}
+
+/*
+ * Helper to prepare DMA descriptors for configuring registers
+ * before writing each codeword in NAND page.
+ */
+static void config_nand_cw_write(struct qcom_nand_controller *nandc)
+{
+	write_reg_dma(nandc, NAND_FLASH_CMD, 1, NAND_BAM_NEXT_SGL);
+	write_reg_dma(nandc, NAND_EXEC_CMD, 1, NAND_BAM_NEXT_SGL);
+
+	read_reg_dma(nandc, NAND_FLASH_STATUS, 1, NAND_BAM_NEXT_SGL);
+
+	write_reg_dma(nandc, NAND_FLASH_STATUS, 1, 0);
+	write_reg_dma(nandc, NAND_READ_STATUS, 1, NAND_BAM_NEXT_SGL);
+}
+
+/*
+ * the following functions are used within chip->cmdfunc() to perform different
+ * NAND_CMD_* commands
+ */
+
+/* sets up descriptors for NAND_CMD_PARAM */
+static int nandc_param(struct qcom_nand_host *host)
+{
+	struct nand_chip *chip = &host->chip;
+	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+
+	/*
+	 * NAND_CMD_PARAM is called before we know much about the FLASH chip
+	 * in use. we configure the controller to perform a raw read of 512
+	 * bytes to read onfi params
+	 */
+	nandc_set_reg(nandc, NAND_FLASH_CMD, OP_PAGE_READ | PAGE_ACC | LAST_PAGE);
+	nandc_set_reg(nandc, NAND_ADDR0, 0);
+	nandc_set_reg(nandc, NAND_ADDR1, 0);
+	nandc_set_reg(nandc, NAND_DEV0_CFG0, 0 << CW_PER_PAGE
+					| 512 << UD_SIZE_BYTES
+					| 5 << NUM_ADDR_CYCLES
+					| 0 << SPARE_SIZE_BYTES);
+	nandc_set_reg(nandc, NAND_DEV0_CFG1, 7 << NAND_RECOVERY_CYCLES
+					| 0 << CS_ACTIVE_BSY
+					| 17 << BAD_BLOCK_BYTE_NUM
+					| 1 << BAD_BLOCK_IN_SPARE_AREA
+					| 2 << WR_RD_BSY_GAP
+					| 0 << WIDE_FLASH
+					| 1 << DEV0_CFG1_ECC_DISABLE);
+	nandc_set_reg(nandc, NAND_EBI2_ECC_BUF_CFG, 1 << ECC_CFG_ECC_DISABLE);
+
+	/* configure CMD1 and VLD for ONFI param probing */
+	nandc_set_reg(nandc, NAND_DEV_CMD_VLD,
+		      (nandc->vld & ~READ_START_VLD));
+	nandc_set_reg(nandc, NAND_DEV_CMD1,
+		      (nandc->cmd1 & ~(0xFF << READ_ADDR))
+		      | NAND_CMD_PARAM << READ_ADDR);
+
+	nandc_set_reg(nandc, NAND_EXEC_CMD, 1);
+
+	nandc_set_reg(nandc, NAND_DEV_CMD1_RESTORE, nandc->cmd1);
+	nandc_set_reg(nandc, NAND_DEV_CMD_VLD_RESTORE, nandc->vld);
+	nandc_set_read_loc(nandc, 0, 0, 512, 1);
+
+	write_reg_dma(nandc, NAND_DEV_CMD_VLD, 1, 0);
+	write_reg_dma(nandc, NAND_DEV_CMD1, 1, NAND_BAM_NEXT_SGL);
+
+	nandc->buf_count = 512;
+	memset(nandc->data_buffer, 0xff, nandc->buf_count);
+
+	config_nand_single_cw_page_read(nandc, false);
+
+	read_data_dma(nandc, FLASH_BUF_ACC, nandc->data_buffer,
+		      nandc->buf_count, 0);
+
+	/* restore CMD1 and VLD regs */
+	write_reg_dma(nandc, NAND_DEV_CMD1_RESTORE, 1, 0);
+	write_reg_dma(nandc, NAND_DEV_CMD_VLD_RESTORE, 1, NAND_BAM_NEXT_SGL);
+
+	return 0;
+}
+
+/* sets up descriptors for NAND_CMD_ERASE1 */
+static int erase_block(struct qcom_nand_host *host, int page_addr)
+{
+	struct nand_chip *chip = &host->chip;
+	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+
+	nandc_set_reg(nandc, NAND_FLASH_CMD,
+		      OP_BLOCK_ERASE | PAGE_ACC | LAST_PAGE);
+	nandc_set_reg(nandc, NAND_ADDR0, page_addr);
+	nandc_set_reg(nandc, NAND_ADDR1, 0);
+	nandc_set_reg(nandc, NAND_DEV0_CFG0,
+		      host->cfg0_raw & ~(7 << CW_PER_PAGE));
+	nandc_set_reg(nandc, NAND_DEV0_CFG1, host->cfg1_raw);
+	nandc_set_reg(nandc, NAND_EXEC_CMD, 1);
+	nandc_set_reg(nandc, NAND_FLASH_STATUS, host->clrflashstatus);
+	nandc_set_reg(nandc, NAND_READ_STATUS, host->clrreadstatus);
+
+	write_reg_dma(nandc, NAND_FLASH_CMD, 3, NAND_BAM_NEXT_SGL);
+	write_reg_dma(nandc, NAND_DEV0_CFG0, 2, NAND_BAM_NEXT_SGL);
+	write_reg_dma(nandc, NAND_EXEC_CMD, 1, NAND_BAM_NEXT_SGL);
+
+	read_reg_dma(nandc, NAND_FLASH_STATUS, 1, NAND_BAM_NEXT_SGL);
+
+	write_reg_dma(nandc, NAND_FLASH_STATUS, 1, 0);
+	write_reg_dma(nandc, NAND_READ_STATUS, 1, NAND_BAM_NEXT_SGL);
+
+	return 0;
+}
+
+/* sets up descriptors for NAND_CMD_READID */
+static int read_id(struct qcom_nand_host *host, int column)
+{
+	struct nand_chip *chip = &host->chip;
+	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+
+	if (column == -1)
+		return 0;
+
+	nandc_set_reg(nandc, NAND_FLASH_CMD, OP_FETCH_ID);
+	nandc_set_reg(nandc, NAND_ADDR0, column);
+	nandc_set_reg(nandc, NAND_ADDR1, 0);
+	nandc_set_reg(nandc, NAND_FLASH_CHIP_SELECT,
+		      nandc->props->is_bam ? 0 : DM_EN);
+	nandc_set_reg(nandc, NAND_EXEC_CMD, 1);
+
+	write_reg_dma(nandc, NAND_FLASH_CMD, 4, NAND_BAM_NEXT_SGL);
+	write_reg_dma(nandc, NAND_EXEC_CMD, 1, NAND_BAM_NEXT_SGL);
+
+	read_reg_dma(nandc, NAND_READ_ID, 1, NAND_BAM_NEXT_SGL);
+
+	return 0;
+}
+
+/* sets up descriptors for NAND_CMD_RESET */
+static int reset(struct qcom_nand_host *host)
+{
+	struct nand_chip *chip = &host->chip;
+	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+
+	nandc_set_reg(nandc, NAND_FLASH_CMD, OP_RESET_DEVICE);
+	nandc_set_reg(nandc, NAND_EXEC_CMD, 1);
+
+	write_reg_dma(nandc, NAND_FLASH_CMD, 1, NAND_BAM_NEXT_SGL);
+	write_reg_dma(nandc, NAND_EXEC_CMD, 1, NAND_BAM_NEXT_SGL);
+
+	read_reg_dma(nandc, NAND_FLASH_STATUS, 1, NAND_BAM_NEXT_SGL);
+
+	return 0;
+}
+
+/* helpers to submit/free our list of dma descriptors */
+static int submit_descs(struct qcom_nand_controller *nandc)
+{
+	struct desc_info *desc;
+	dma_cookie_t cookie = 0;
+	struct bam_transaction *bam_txn = nandc->bam_txn;
+	int r;
+
+	if (nandc->props->is_bam) {
+		if (bam_txn->rx_sgl_pos > bam_txn->rx_sgl_start) {
+			r = prepare_bam_async_desc(nandc, nandc->rx_chan, 0);
+			if (r)
+				return r;
+		}
+
+		if (bam_txn->tx_sgl_pos > bam_txn->tx_sgl_start) {
+			r = prepare_bam_async_desc(nandc, nandc->tx_chan,
+						   DMA_PREP_INTERRUPT);
+			if (r)
+				return r;
+		}
+
+		if (bam_txn->cmd_sgl_pos > bam_txn->cmd_sgl_start) {
+			r = prepare_bam_async_desc(nandc, nandc->cmd_chan,
+						   DMA_PREP_CMD);
+			if (r)
+				return r;
+		}
+	}
+
+	list_for_each_entry(desc, &nandc->desc_list, node)
+		cookie = dmaengine_submit(desc->dma_desc);
+
+	if (nandc->props->is_bam) {
+		bam_txn->last_cmd_desc->callback = qpic_bam_dma_done;
+		bam_txn->last_cmd_desc->callback_param = bam_txn;
+		if (bam_txn->last_data_desc) {
+			bam_txn->last_data_desc->callback = qpic_bam_dma_done;
+			bam_txn->last_data_desc->callback_param = bam_txn;
+			bam_txn->wait_second_completion = true;
+		}
+
+		dma_async_issue_pending(nandc->tx_chan);
+		dma_async_issue_pending(nandc->rx_chan);
+		dma_async_issue_pending(nandc->cmd_chan);
+
+		if (!wait_for_completion_timeout(&bam_txn->txn_done,
+						 QPIC_NAND_COMPLETION_TIMEOUT))
+			return -ETIMEDOUT;
+	} else {
+		if (dma_sync_wait(nandc->chan, cookie) != DMA_COMPLETE)
+			return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
+static void free_descs(struct qcom_nand_controller *nandc)
+{
+	struct desc_info *desc, *n;
+
+	list_for_each_entry_safe(desc, n, &nandc->desc_list, node) {
+		list_del(&desc->node);
+
+		if (nandc->props->is_bam)
+			dma_unmap_sg(nandc->dev, desc->bam_sgl,
+				     desc->sgl_cnt, desc->dir);
+		else
+			dma_unmap_sg(nandc->dev, &desc->adm_sgl, 1,
+				     desc->dir);
+
+		kfree(desc);
+	}
+}
+
+/* reset the register read buffer for next NAND operation */
+static void clear_read_regs(struct qcom_nand_controller *nandc)
+{
+	nandc->reg_read_pos = 0;
+	nandc_read_buffer_sync(nandc, false);
+}
+
+static void pre_command(struct qcom_nand_host *host, int command)
+{
+	struct nand_chip *chip = &host->chip;
+	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+
+	nandc->buf_count = 0;
+	nandc->buf_start = 0;
+	host->use_ecc = false;
+	host->last_command = command;
+
+	clear_read_regs(nandc);
+
+	if (command == NAND_CMD_RESET || command == NAND_CMD_READID ||
+	    command == NAND_CMD_PARAM || command == NAND_CMD_ERASE1)
+		clear_bam_transaction(nandc);
+}
+
+/*
+ * this is called after NAND_CMD_PAGEPROG and NAND_CMD_ERASE1 to set our
+ * privately maintained status byte, this status byte can be read after
+ * NAND_CMD_STATUS is called
+ */
+static void parse_erase_write_errors(struct qcom_nand_host *host, int command)
+{
+	struct nand_chip *chip = &host->chip;
+	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+	struct nand_ecc_ctrl *ecc = &chip->ecc;
+	int num_cw;
+	int i;
+
+	num_cw = command == NAND_CMD_PAGEPROG ? ecc->steps : 1;
+	nandc_read_buffer_sync(nandc, true);
+
+	for (i = 0; i < num_cw; i++) {
+		u32 flash_status = le32_to_cpu(nandc->reg_read_buf[i]);
+
+		if (flash_status & FS_MPU_ERR)
+			host->status &= ~NAND_STATUS_WP;
+
+		if (flash_status & FS_OP_ERR || (i == (num_cw - 1) &&
+						 (flash_status &
+						  FS_DEVICE_STS_ERR)))
+			host->status |= NAND_STATUS_FAIL;
+	}
+}
+
+static void post_command(struct qcom_nand_host *host, int command)
+{
+	struct nand_chip *chip = &host->chip;
+	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+
+	switch (command) {
+	case NAND_CMD_READID:
+		nandc_read_buffer_sync(nandc, true);
+		memcpy(nandc->data_buffer, nandc->reg_read_buf,
+		       nandc->buf_count);
+		break;
+	case NAND_CMD_PAGEPROG:
+	case NAND_CMD_ERASE1:
+		parse_erase_write_errors(host, command);
+		break;
+	default:
+		break;
+	}
+}
+
+/*
+ * Implements chip->cmdfunc. It's  only used for a limited set of commands.
+ * The rest of the commands wouldn't be called by upper layers. For example,
+ * NAND_CMD_READOOB would never be called because we have our own versions
+ * of read_oob ops for nand_ecc_ctrl.
+ */
+static void qcom_nandc_command(struct mtd_info *mtd, unsigned int command,
+			       int column, int page_addr)
+{
+	struct nand_chip *chip = mtd_to_nand(mtd);
+	struct qcom_nand_host *host = to_qcom_nand_host(chip);
+	struct nand_ecc_ctrl *ecc = &chip->ecc;
+	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+	bool wait = false;
+	int ret = 0;
+
+	pre_command(host, command);
+
+	switch (command) {
+	case NAND_CMD_RESET:
+		ret = reset(host);
+		wait = true;
+		break;
+
+	case NAND_CMD_READID:
+		nandc->buf_count = 4;
+		ret = read_id(host, column);
+		wait = true;
+		break;
+
+	case NAND_CMD_PARAM:
+		ret = nandc_param(host);
+		wait = true;
+		break;
+
+	case NAND_CMD_ERASE1:
+		ret = erase_block(host, page_addr);
+		wait = true;
+		break;
+
+	case NAND_CMD_READ0:
+		/* we read the entire page for now */
+		WARN_ON(column != 0);
+
+		host->use_ecc = true;
+		set_address(host, 0, page_addr);
+		update_rw_regs(host, ecc->steps, true);
+		break;
+
+	case NAND_CMD_SEQIN:
+		WARN_ON(column != 0);
+		set_address(host, 0, page_addr);
+		break;
+
+	case NAND_CMD_PAGEPROG:
+	case NAND_CMD_STATUS:
+	case NAND_CMD_NONE:
+	default:
+		break;
+	}
+
+	if (ret) {
+		dev_err(nandc->dev, "failure executing command %d\n",
+			command);
+		free_descs(nandc);
+		return;
+	}
+
+	if (wait) {
+		ret = submit_descs(nandc);
+		if (ret)
+			dev_err(nandc->dev,
+				"failure submitting descs for command %d\n",
+				command);
+	}
+
+	free_descs(nandc);
+
+	post_command(host, command);
+}
+
+/*
+ * when using BCH ECC, the HW flags an error in NAND_FLASH_STATUS if it read
+ * an erased CW, and reports an erased CW in NAND_ERASED_CW_DETECT_STATUS.
+ *
+ * when using RS ECC, the HW reports the same erros when reading an erased CW,
+ * but it notifies that it is an erased CW by placing special characters at
+ * certain offsets in the buffer.
+ *
+ * verify if the page is erased or not, and fix up the page for RS ECC by
+ * replacing the special characters with 0xff.
+ */
+static bool erased_chunk_check_and_fixup(u8 *data_buf, int data_len)
+{
+	u8 empty1, empty2;
+
+	/*
+	 * an erased page flags an error in NAND_FLASH_STATUS, check if the page
+	 * is erased by looking for 0x54s at offsets 3 and 175 from the
+	 * beginning of each codeword
+	 */
+
+	empty1 = data_buf[3];
+	empty2 = data_buf[175];
+
+	/*
+	 * if the erased codework markers, if they exist override them with
+	 * 0xffs
+	 */
+	if ((empty1 == 0x54 && empty2 == 0xff) ||
+	    (empty1 == 0xff && empty2 == 0x54)) {
+		data_buf[3] = 0xff;
+		data_buf[175] = 0xff;
+	}
+
+	/*
+	 * check if the entire chunk contains 0xffs or not. if it doesn't, then
+	 * restore the original values at the special offsets
+	 */
+	if (memchr_inv(data_buf, 0xff, data_len)) {
+		data_buf[3] = empty1;
+		data_buf[175] = empty2;
+
+		return false;
+	}
+
+	return true;
+}
+
+struct read_stats {
+	__le32 flash;
+	__le32 buffer;
+	__le32 erased_cw;
+};
+
+/* reads back FLASH_STATUS register set by the controller */
+static int check_flash_errors(struct qcom_nand_host *host, int cw_cnt)
+{
+	struct nand_chip *chip = &host->chip;
+	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+	int i;
+
+	nandc_read_buffer_sync(nandc, true);
+
+	for (i = 0; i < cw_cnt; i++) {
+		u32 flash = le32_to_cpu(nandc->reg_read_buf[i]);
+
+		if (flash & (FS_OP_ERR | FS_MPU_ERR))
+			return -EIO;
+	}
+
+	return 0;
+}
+
+/* performs raw read for one codeword */
+static int
+qcom_nandc_read_cw_raw(struct mtd_info *mtd, struct nand_chip *chip,
+		       u8 *data_buf, u8 *oob_buf, int page, int cw)
+{
+	struct qcom_nand_host *host = to_qcom_nand_host(chip);
+	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+	struct nand_ecc_ctrl *ecc = &chip->ecc;
+	int data_size1, data_size2, oob_size1, oob_size2;
+	int ret, reg_off = FLASH_BUF_ACC, read_loc = 0;
+
+	nand_read_page_op(chip, page, 0, NULL, 0);
+	host->use_ecc = false;
+
+	clear_bam_transaction(nandc);
+	set_address(host, host->cw_size * cw, page);
+	update_rw_regs(host, 1, true);
+	config_nand_page_read(nandc);
+
+	data_size1 = mtd->writesize - host->cw_size * (ecc->steps - 1);
+	oob_size1 = host->bbm_size;
+
+	if (cw == (ecc->steps - 1)) {
+		data_size2 = ecc->size - data_size1 -
+			     ((ecc->steps - 1) * 4);
+		oob_size2 = (ecc->steps * 4) + host->ecc_bytes_hw +
+			    host->spare_bytes;
+	} else {
+		data_size2 = host->cw_data - data_size1;
+		oob_size2 = host->ecc_bytes_hw + host->spare_bytes;
+	}
+
+	if (nandc->props->is_bam) {
+		nandc_set_read_loc(nandc, 0, read_loc, data_size1, 0);
+		read_loc += data_size1;
+
+		nandc_set_read_loc(nandc, 1, read_loc, oob_size1, 0);
+		read_loc += oob_size1;
+
+		nandc_set_read_loc(nandc, 2, read_loc, data_size2, 0);
+		read_loc += data_size2;
+
+		nandc_set_read_loc(nandc, 3, read_loc, oob_size2, 1);
+	}
+
+	config_nand_cw_read(nandc, false);
+
+	read_data_dma(nandc, reg_off, data_buf, data_size1, 0);
+	reg_off += data_size1;
+
+	read_data_dma(nandc, reg_off, oob_buf, oob_size1, 0);
+	reg_off += oob_size1;
+
+	read_data_dma(nandc, reg_off, data_buf + data_size1, data_size2, 0);
+	reg_off += data_size2;
+
+	read_data_dma(nandc, reg_off, oob_buf + oob_size1, oob_size2, 0);
+
+	ret = submit_descs(nandc);
+	free_descs(nandc);
+	if (ret) {
+		dev_err(nandc->dev, "failure to read raw cw %d\n", cw);
+		return ret;
+	}
+
+	return check_flash_errors(host, 1);
+}
+
+/*
+ * Bitflips can happen in erased codewords also so this function counts the
+ * number of 0 in each CW for which ECC engine returns the uncorrectable
+ * error. The page will be assumed as erased if this count is less than or
+ * equal to the ecc->strength for each CW.
+ *
+ * 1. Both DATA and OOB need to be checked for number of 0. The
+ *    top-level API can be called with only data buf or OOB buf so use
+ *    chip->data_buf if data buf is null and chip->oob_poi if oob buf
+ *    is null for copying the raw bytes.
+ * 2. Perform raw read for all the CW which has uncorrectable errors.
+ * 3. For each CW, check the number of 0 in cw_data and usable OOB bytes.
+ *    The BBM and spare bytes bit flip won’t affect the ECC so don’t check
+ *    the number of bitflips in this area.
+ */
+static int
+check_for_erased_page(struct qcom_nand_host *host, u8 *data_buf,
+		      u8 *oob_buf, unsigned long uncorrectable_cws,
+		      int page, unsigned int max_bitflips)
+{
+	struct nand_chip *chip = &host->chip;
+	struct mtd_info *mtd = nand_to_mtd(chip);
+	struct nand_ecc_ctrl *ecc = &chip->ecc;
+	u8 *cw_data_buf, *cw_oob_buf;
+	int cw, data_size, oob_size, ret = 0;
+
+	if (!data_buf) {
+		data_buf = chip->data_buf;
+		chip->pagebuf = -1;
+	}
+
+	if (!oob_buf) {
+		oob_buf = chip->oob_poi;
+		chip->pagebuf = -1;
+	}
+
+	for_each_set_bit(cw, &uncorrectable_cws, ecc->steps) {
+		if (cw == (ecc->steps - 1)) {
+			data_size = ecc->size - ((ecc->steps - 1) * 4);
+			oob_size = (ecc->steps * 4) + host->ecc_bytes_hw;
+		} else {
+			data_size = host->cw_data;
+			oob_size = host->ecc_bytes_hw;
+		}
+
+		/* determine starting buffer address for current CW */
+		cw_data_buf = data_buf + (cw * host->cw_data);
+		cw_oob_buf = oob_buf + (cw * ecc->bytes);
+
+		ret = qcom_nandc_read_cw_raw(mtd, chip, cw_data_buf,
+					     cw_oob_buf, page, cw);
+		if (ret)
+			return ret;
+
+		/*
+		 * make sure it isn't an erased page reported
+		 * as not-erased by HW because of a few bitflips
+		 */
+		ret = nand_check_erased_ecc_chunk(cw_data_buf, data_size,
+						  cw_oob_buf + host->bbm_size,
+						  oob_size, NULL,
+						  0, ecc->strength);
+		if (ret < 0) {
+			mtd->ecc_stats.failed++;
+		} else {
+			mtd->ecc_stats.corrected += ret;
+			max_bitflips = max_t(unsigned int, max_bitflips, ret);
+		}
+	}
+
+	return max_bitflips;
+}
+
+/*
+ * reads back status registers set by the controller to notify page read
+ * errors. this is equivalent to what 'ecc->correct()' would do.
+ */
+static int parse_read_errors(struct qcom_nand_host *host, u8 *data_buf,
+			     u8 *oob_buf, int page)
+{
+	struct nand_chip *chip = &host->chip;
+	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+	struct mtd_info *mtd = nand_to_mtd(chip);
+	struct nand_ecc_ctrl *ecc = &chip->ecc;
+	unsigned int max_bitflips = 0, uncorrectable_cws = 0;
+	struct read_stats *buf;
+	bool flash_op_err = false, erased;
+	int i;
+	u8 *data_buf_start = data_buf, *oob_buf_start = oob_buf;
+
+	buf = (struct read_stats *)nandc->reg_read_buf;
+	nandc_read_buffer_sync(nandc, true);
+
+	for (i = 0; i < ecc->steps; i++, buf++) {
+		u32 flash, buffer, erased_cw;
+		int data_len, oob_len;
+
+		if (i == (ecc->steps - 1)) {
+			data_len = ecc->size - ((ecc->steps - 1) << 2);
+			oob_len = ecc->steps << 2;
+		} else {
+			data_len = host->cw_data;
+			oob_len = 0;
+		}
+
+		flash = le32_to_cpu(buf->flash);
+		buffer = le32_to_cpu(buf->buffer);
+		erased_cw = le32_to_cpu(buf->erased_cw);
+
+		/*
+		 * Check ECC failure for each codeword. ECC failure can
+		 * happen in either of the following conditions
+		 * 1. If number of bitflips are greater than ECC engine
+		 *    capability.
+		 * 2. If this codeword contains all 0xff for which erased
+		 *    codeword detection check will be done.
+		 */
+		if ((flash & FS_OP_ERR) && (buffer & BS_UNCORRECTABLE_BIT)) {
+			/*
+			 * For BCH ECC, ignore erased codeword errors, if
+			 * ERASED_CW bits are set.
+			 */
+			if (host->bch_enabled) {
+				erased = (erased_cw & ERASED_CW) == ERASED_CW ?
+					 true : false;
+			/*
+			 * For RS ECC, HW reports the erased CW by placing
+			 * special characters at certain offsets in the buffer.
+			 * These special characters will be valid only if
+			 * complete page is read i.e. data_buf is not NULL.
+			 */
+			} else if (data_buf) {
+				erased = erased_chunk_check_and_fixup(data_buf,
+								      data_len);
+			} else {
+				erased = false;
+			}
+
+			if (!erased)
+				uncorrectable_cws |= BIT(i);
+		/*
+		 * Check if MPU or any other operational error (timeout,
+		 * device failure, etc.) happened for this codeword and
+		 * make flash_op_err true. If flash_op_err is set, then
+		 * EIO will be returned for page read.
+		 */
+		} else if (flash & (FS_OP_ERR | FS_MPU_ERR)) {
+			flash_op_err = true;
+		/*
+		 * No ECC or operational errors happened. Check the number of
+		 * bits corrected and update the ecc_stats.corrected.
+		 */
+		} else {
+			unsigned int stat;
+
+			stat = buffer & BS_CORRECTABLE_ERR_MSK;
+			mtd->ecc_stats.corrected += stat;
+			max_bitflips = max(max_bitflips, stat);
+		}
+
+		if (data_buf)
+			data_buf += data_len;
+		if (oob_buf)
+			oob_buf += oob_len + ecc->bytes;
+	}
+
+	if (flash_op_err)
+		return -EIO;
+
+	if (!uncorrectable_cws)
+		return max_bitflips;
+
+	return check_for_erased_page(host, data_buf_start, oob_buf_start,
+				     uncorrectable_cws, page,
+				     max_bitflips);
+}
+
+/*
+ * helper to perform the actual page read operation, used by ecc->read_page(),
+ * ecc->read_oob()
+ */
+static int read_page_ecc(struct qcom_nand_host *host, u8 *data_buf,
+			 u8 *oob_buf, int page)
+{
+	struct nand_chip *chip = &host->chip;
+	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+	struct nand_ecc_ctrl *ecc = &chip->ecc;
+	u8 *data_buf_start = data_buf, *oob_buf_start = oob_buf;
+	int i, ret;
+
+	config_nand_page_read(nandc);
+
+	/* queue cmd descs for each codeword */
+	for (i = 0; i < ecc->steps; i++) {
+		int data_size, oob_size;
+
+		if (i == (ecc->steps - 1)) {
+			data_size = ecc->size - ((ecc->steps - 1) << 2);
+			oob_size = (ecc->steps << 2) + host->ecc_bytes_hw +
+				   host->spare_bytes;
+		} else {
+			data_size = host->cw_data;
+			oob_size = host->ecc_bytes_hw + host->spare_bytes;
+		}
+
+		if (nandc->props->is_bam) {
+			if (data_buf && oob_buf) {
+				nandc_set_read_loc(nandc, 0, 0, data_size, 0);
+				nandc_set_read_loc(nandc, 1, data_size,
+						   oob_size, 1);
+			} else if (data_buf) {
+				nandc_set_read_loc(nandc, 0, 0, data_size, 1);
+			} else {
+				nandc_set_read_loc(nandc, 0, data_size,
+						   oob_size, 1);
+			}
+		}
+
+		config_nand_cw_read(nandc, true);
+
+		if (data_buf)
+			read_data_dma(nandc, FLASH_BUF_ACC, data_buf,
+				      data_size, 0);
+
+		/*
+		 * when ecc is enabled, the controller doesn't read the real
+		 * or dummy bad block markers in each chunk. To maintain a
+		 * consistent layout across RAW and ECC reads, we just
+		 * leave the real/dummy BBM offsets empty (i.e, filled with
+		 * 0xffs)
+		 */
+		if (oob_buf) {
+			int j;
+
+			for (j = 0; j < host->bbm_size; j++)
+				*oob_buf++ = 0xff;
+
+			read_data_dma(nandc, FLASH_BUF_ACC + data_size,
+				      oob_buf, oob_size, 0);
+		}
+
+		if (data_buf)
+			data_buf += data_size;
+		if (oob_buf)
+			oob_buf += oob_size;
+	}
+
+	ret = submit_descs(nandc);
+	free_descs(nandc);
+
+	if (ret) {
+		dev_err(nandc->dev, "failure to read page/oob\n");
+		return ret;
+	}
+
+	return parse_read_errors(host, data_buf_start, oob_buf_start, page);
+}
+
+/*
+ * a helper that copies the last step/codeword of a page (containing free oob)
+ * into our local buffer
+ */
+static int copy_last_cw(struct qcom_nand_host *host, int page)
+{
+	struct nand_chip *chip = &host->chip;
+	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+	struct nand_ecc_ctrl *ecc = &chip->ecc;
+	int size;
+	int ret;
+
+	clear_read_regs(nandc);
+
+	size = host->use_ecc ? host->cw_data : host->cw_size;
+
+	/* prepare a clean read buffer */
+	memset(nandc->data_buffer, 0xff, size);
+
+	set_address(host, host->cw_size * (ecc->steps - 1), page);
+	update_rw_regs(host, 1, true);
+
+	config_nand_single_cw_page_read(nandc, host->use_ecc);
+
+	read_data_dma(nandc, FLASH_BUF_ACC, nandc->data_buffer, size, 0);
+
+	ret = submit_descs(nandc);
+	if (ret)
+		dev_err(nandc->dev, "failed to copy last codeword\n");
+
+	free_descs(nandc);
+
+	return ret;
+}
+
+/* implements ecc->read_page() */
+static int qcom_nandc_read_page(struct mtd_info *mtd, struct nand_chip *chip,
+				uint8_t *buf, int oob_required, int page)
+{
+	struct qcom_nand_host *host = to_qcom_nand_host(chip);
+	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+	u8 *data_buf, *oob_buf = NULL;
+
+	nand_read_page_op(chip, page, 0, NULL, 0);
+	data_buf = buf;
+	oob_buf = oob_required ? chip->oob_poi : NULL;
+
+	clear_bam_transaction(nandc);
+
+	return read_page_ecc(host, data_buf, oob_buf, page);
+}
+
+/* implements ecc->read_page_raw() */
+static int qcom_nandc_read_page_raw(struct mtd_info *mtd,
+				    struct nand_chip *chip, uint8_t *buf,
+				    int oob_required, int page)
+{
+	struct qcom_nand_host *host = to_qcom_nand_host(chip);
+	struct nand_ecc_ctrl *ecc = &chip->ecc;
+	int cw, ret;
+	u8 *data_buf = buf, *oob_buf = chip->oob_poi;
+
+	for (cw = 0; cw < ecc->steps; cw++) {
+		ret = qcom_nandc_read_cw_raw(mtd, chip, data_buf, oob_buf,
+					     page, cw);
+		if (ret)
+			return ret;
+
+		data_buf += host->cw_data;
+		oob_buf += ecc->bytes;
+	}
+
+	return 0;
+}
+
+/* implements ecc->read_oob() */
+static int qcom_nandc_read_oob(struct mtd_info *mtd, struct nand_chip *chip,
+			       int page)
+{
+	struct qcom_nand_host *host = to_qcom_nand_host(chip);
+	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+	struct nand_ecc_ctrl *ecc = &chip->ecc;
+
+	clear_read_regs(nandc);
+	clear_bam_transaction(nandc);
+
+	host->use_ecc = true;
+	set_address(host, 0, page);
+	update_rw_regs(host, ecc->steps, true);
+
+	return read_page_ecc(host, NULL, chip->oob_poi, page);
+}
+
+/* implements ecc->write_page() */
+static int qcom_nandc_write_page(struct mtd_info *mtd, struct nand_chip *chip,
+				 const uint8_t *buf, int oob_required, int page)
+{
+	struct qcom_nand_host *host = to_qcom_nand_host(chip);
+	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+	struct nand_ecc_ctrl *ecc = &chip->ecc;
+	u8 *data_buf, *oob_buf;
+	int i, ret;
+
+	nand_prog_page_begin_op(chip, page, 0, NULL, 0);
+
+	clear_read_regs(nandc);
+	clear_bam_transaction(nandc);
+
+	data_buf = (u8 *)buf;
+	oob_buf = chip->oob_poi;
+
+	host->use_ecc = true;
+	update_rw_regs(host, ecc->steps, false);
+	config_nand_page_write(nandc);
+
+	for (i = 0; i < ecc->steps; i++) {
+		int data_size, oob_size;
+
+		if (i == (ecc->steps - 1)) {
+			data_size = ecc->size - ((ecc->steps - 1) << 2);
+			oob_size = (ecc->steps << 2) + host->ecc_bytes_hw +
+				   host->spare_bytes;
+		} else {
+			data_size = host->cw_data;
+			oob_size = ecc->bytes;
+		}
+
+
+		write_data_dma(nandc, FLASH_BUF_ACC, data_buf, data_size,
+			       i == (ecc->steps - 1) ? NAND_BAM_NO_EOT : 0);
+
+		/*
+		 * when ECC is enabled, we don't really need to write anything
+		 * to oob for the first n - 1 codewords since these oob regions
+		 * just contain ECC bytes that's written by the controller
+		 * itself. For the last codeword, we skip the bbm positions and
+		 * write to the free oob area.
+		 */
+		if (i == (ecc->steps - 1)) {
+			oob_buf += host->bbm_size;
+
+			write_data_dma(nandc, FLASH_BUF_ACC + data_size,
+				       oob_buf, oob_size, 0);
+		}
+
+		config_nand_cw_write(nandc);
+
+		data_buf += data_size;
+		oob_buf += oob_size;
+	}
+
+	ret = submit_descs(nandc);
+	if (ret)
+		dev_err(nandc->dev, "failure to write page\n");
+
+	free_descs(nandc);
+
+	if (!ret)
+		ret = nand_prog_page_end_op(chip);
+
+	return ret;
+}
+
+/* implements ecc->write_page_raw() */
+static int qcom_nandc_write_page_raw(struct mtd_info *mtd,
+				     struct nand_chip *chip, const uint8_t *buf,
+				     int oob_required, int page)
+{
+	struct qcom_nand_host *host = to_qcom_nand_host(chip);
+	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+	struct nand_ecc_ctrl *ecc = &chip->ecc;
+	u8 *data_buf, *oob_buf;
+	int i, ret;
+
+	nand_prog_page_begin_op(chip, page, 0, NULL, 0);
+	clear_read_regs(nandc);
+	clear_bam_transaction(nandc);
+
+	data_buf = (u8 *)buf;
+	oob_buf = chip->oob_poi;
+
+	host->use_ecc = false;
+	update_rw_regs(host, ecc->steps, false);
+	config_nand_page_write(nandc);
+
+	for (i = 0; i < ecc->steps; i++) {
+		int data_size1, data_size2, oob_size1, oob_size2;
+		int reg_off = FLASH_BUF_ACC;
+
+		data_size1 = mtd->writesize - host->cw_size * (ecc->steps - 1);
+		oob_size1 = host->bbm_size;
+
+		if (i == (ecc->steps - 1)) {
+			data_size2 = ecc->size - data_size1 -
+				     ((ecc->steps - 1) << 2);
+			oob_size2 = (ecc->steps << 2) + host->ecc_bytes_hw +
+				    host->spare_bytes;
+		} else {
+			data_size2 = host->cw_data - data_size1;
+			oob_size2 = host->ecc_bytes_hw + host->spare_bytes;
+		}
+
+		write_data_dma(nandc, reg_off, data_buf, data_size1,
+			       NAND_BAM_NO_EOT);
+		reg_off += data_size1;
+		data_buf += data_size1;
+
+		write_data_dma(nandc, reg_off, oob_buf, oob_size1,
+			       NAND_BAM_NO_EOT);
+		reg_off += oob_size1;
+		oob_buf += oob_size1;
+
+		write_data_dma(nandc, reg_off, data_buf, data_size2,
+			       NAND_BAM_NO_EOT);
+		reg_off += data_size2;
+		data_buf += data_size2;
+
+		write_data_dma(nandc, reg_off, oob_buf, oob_size2, 0);
+		oob_buf += oob_size2;
+
+		config_nand_cw_write(nandc);
+	}
+
+	ret = submit_descs(nandc);
+	if (ret)
+		dev_err(nandc->dev, "failure to write raw page\n");
+
+	free_descs(nandc);
+
+	if (!ret)
+		ret = nand_prog_page_end_op(chip);
+
+	return ret;
+}
+
+/*
+ * implements ecc->write_oob()
+ *
+ * the NAND controller cannot write only data or only OOB within a codeword
+ * since ECC is calculated for the combined codeword. So update the OOB from
+ * chip->oob_poi, and pad the data area with OxFF before writing.
+ */
+static int qcom_nandc_write_oob(struct mtd_info *mtd, struct nand_chip *chip,
+				int page)
+{
+	struct qcom_nand_host *host = to_qcom_nand_host(chip);
+	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+	struct nand_ecc_ctrl *ecc = &chip->ecc;
+	u8 *oob = chip->oob_poi;
+	int data_size, oob_size;
+	int ret;
+
+	host->use_ecc = true;
+	clear_bam_transaction(nandc);
+
+	/* calculate the data and oob size for the last codeword/step */
+	data_size = ecc->size - ((ecc->steps - 1) << 2);
+	oob_size = mtd->oobavail;
+
+	memset(nandc->data_buffer, 0xff, host->cw_data);
+	/* override new oob content to last codeword */
+	mtd_ooblayout_get_databytes(mtd, nandc->data_buffer + data_size, oob,
+				    0, mtd->oobavail);
+
+	set_address(host, host->cw_size * (ecc->steps - 1), page);
+	update_rw_regs(host, 1, false);
+
+	config_nand_page_write(nandc);
+	write_data_dma(nandc, FLASH_BUF_ACC,
+		       nandc->data_buffer, data_size + oob_size, 0);
+	config_nand_cw_write(nandc);
+
+	ret = submit_descs(nandc);
+
+	free_descs(nandc);
+
+	if (ret) {
+		dev_err(nandc->dev, "failure to write oob\n");
+		return -EIO;
+	}
+
+	return nand_prog_page_end_op(chip);
+}
+
+static int qcom_nandc_block_bad(struct mtd_info *mtd, loff_t ofs)
+{
+	struct nand_chip *chip = mtd_to_nand(mtd);
+	struct qcom_nand_host *host = to_qcom_nand_host(chip);
+	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+	struct nand_ecc_ctrl *ecc = &chip->ecc;
+	int page, ret, bbpos, bad = 0;
+
+	page = (int)(ofs >> chip->page_shift) & chip->pagemask;
+
+	/*
+	 * configure registers for a raw sub page read, the address is set to
+	 * the beginning of the last codeword, we don't care about reading ecc
+	 * portion of oob. we just want the first few bytes from this codeword
+	 * that contains the BBM
+	 */
+	host->use_ecc = false;
+
+	clear_bam_transaction(nandc);
+	ret = copy_last_cw(host, page);
+	if (ret)
+		goto err;
+
+	if (check_flash_errors(host, 1)) {
+		dev_warn(nandc->dev, "error when trying to read BBM\n");
+		goto err;
+	}
+
+	bbpos = mtd->writesize - host->cw_size * (ecc->steps - 1);
+
+	bad = nandc->data_buffer[bbpos] != 0xff;
+
+	if (chip->options & NAND_BUSWIDTH_16)
+		bad = bad || (nandc->data_buffer[bbpos + 1] != 0xff);
+err:
+	return bad;
+}
+
+static int qcom_nandc_block_markbad(struct mtd_info *mtd, loff_t ofs)
+{
+	struct nand_chip *chip = mtd_to_nand(mtd);
+	struct qcom_nand_host *host = to_qcom_nand_host(chip);
+	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+	struct nand_ecc_ctrl *ecc = &chip->ecc;
+	int page, ret;
+
+	clear_read_regs(nandc);
+	clear_bam_transaction(nandc);
+
+	/*
+	 * to mark the BBM as bad, we flash the entire last codeword with 0s.
+	 * we don't care about the rest of the content in the codeword since
+	 * we aren't going to use this block again
+	 */
+	memset(nandc->data_buffer, 0x00, host->cw_size);
+
+	page = (int)(ofs >> chip->page_shift) & chip->pagemask;
+
+	/* prepare write */
+	host->use_ecc = false;
+	set_address(host, host->cw_size * (ecc->steps - 1), page);
+	update_rw_regs(host, 1, false);
+
+	config_nand_page_write(nandc);
+	write_data_dma(nandc, FLASH_BUF_ACC,
+		       nandc->data_buffer, host->cw_size, 0);
+	config_nand_cw_write(nandc);
+
+	ret = submit_descs(nandc);
+
+	free_descs(nandc);
+
+	if (ret) {
+		dev_err(nandc->dev, "failure to update BBM\n");
+		return -EIO;
+	}
+
+	return nand_prog_page_end_op(chip);
+}
+
+/*
+ * the three functions below implement chip->read_byte(), chip->read_buf()
+ * and chip->write_buf() respectively. these aren't used for
+ * reading/writing page data, they are used for smaller data like reading
+ * id, status etc
+ */
+static uint8_t qcom_nandc_read_byte(struct mtd_info *mtd)
+{
+	struct nand_chip *chip = mtd_to_nand(mtd);
+	struct qcom_nand_host *host = to_qcom_nand_host(chip);
+	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+	u8 *buf = nandc->data_buffer;
+	u8 ret = 0x0;
+
+	if (host->last_command == NAND_CMD_STATUS) {
+		ret = host->status;
+
+		host->status = NAND_STATUS_READY | NAND_STATUS_WP;
+
+		return ret;
+	}
+
+	if (nandc->buf_start < nandc->buf_count)
+		ret = buf[nandc->buf_start++];
+
+	return ret;
+}
+
+static void qcom_nandc_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
+{
+	struct nand_chip *chip = mtd_to_nand(mtd);
+	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+	int real_len = min_t(size_t, len, nandc->buf_count - nandc->buf_start);
+
+	memcpy(buf, nandc->data_buffer + nandc->buf_start, real_len);
+	nandc->buf_start += real_len;
+}
+
+static void qcom_nandc_write_buf(struct mtd_info *mtd, const uint8_t *buf,
+				 int len)
+{
+	struct nand_chip *chip = mtd_to_nand(mtd);
+	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+	int real_len = min_t(size_t, len, nandc->buf_count - nandc->buf_start);
+
+	memcpy(nandc->data_buffer + nandc->buf_start, buf, real_len);
+
+	nandc->buf_start += real_len;
+}
+
+/* we support only one external chip for now */
+static void qcom_nandc_select_chip(struct mtd_info *mtd, int chipnr)
+{
+	struct nand_chip *chip = mtd_to_nand(mtd);
+	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+
+	if (chipnr <= 0)
+		return;
+
+	dev_warn(nandc->dev, "invalid chip select\n");
+}
+
+/*
+ * NAND controller page layout info
+ *
+ * Layout with ECC enabled:
+ *
+ * |----------------------|  |---------------------------------|
+ * |           xx.......yy|  |             *********xx.......yy|
+ * |    DATA   xx..ECC..yy|  |    DATA     **SPARE**xx..ECC..yy|
+ * |   (516)   xx.......yy|  |  (516-n*4)  **(n*4)**xx.......yy|
+ * |           xx.......yy|  |             *********xx.......yy|
+ * |----------------------|  |---------------------------------|
+ *     codeword 1,2..n-1                  codeword n
+ *  <---(528/532 Bytes)-->    <-------(528/532 Bytes)--------->
+ *
+ * n = Number of codewords in the page
+ * . = ECC bytes
+ * * = Spare/free bytes
+ * x = Unused byte(s)
+ * y = Reserved byte(s)
+ *
+ * 2K page: n = 4, spare = 16 bytes
+ * 4K page: n = 8, spare = 32 bytes
+ * 8K page: n = 16, spare = 64 bytes
+ *
+ * the qcom nand controller operates at a sub page/codeword level. each
+ * codeword is 528 and 532 bytes for 4 bit and 8 bit ECC modes respectively.
+ * the number of ECC bytes vary based on the ECC strength and the bus width.
+ *
+ * the first n - 1 codewords contains 516 bytes of user data, the remaining
+ * 12/16 bytes consist of ECC and reserved data. The nth codeword contains
+ * both user data and spare(oobavail) bytes that sum up to 516 bytes.
+ *
+ * When we access a page with ECC enabled, the reserved bytes(s) are not
+ * accessible at all. When reading, we fill up these unreadable positions
+ * with 0xffs. When writing, the controller skips writing the inaccessible
+ * bytes.
+ *
+ * Layout with ECC disabled:
+ *
+ * |------------------------------|  |---------------------------------------|
+ * |         yy          xx.......|  |         bb          *********xx.......|
+ * |  DATA1  yy  DATA2   xx..ECC..|  |  DATA1  bb  DATA2   **SPARE**xx..ECC..|
+ * | (size1) yy (size2)  xx.......|  | (size1) bb (size2)  **(n*4)**xx.......|
+ * |         yy          xx.......|  |         bb          *********xx.......|
+ * |------------------------------|  |---------------------------------------|
+ *         codeword 1,2..n-1                        codeword n
+ *  <-------(528/532 Bytes)------>    <-----------(528/532 Bytes)----------->
+ *
+ * n = Number of codewords in the page
+ * . = ECC bytes
+ * * = Spare/free bytes
+ * x = Unused byte(s)
+ * y = Dummy Bad Bock byte(s)
+ * b = Real Bad Block byte(s)
+ * size1/size2 = function of codeword size and 'n'
+ *
+ * when the ECC block is disabled, one reserved byte (or two for 16 bit bus
+ * width) is now accessible. For the first n - 1 codewords, these are dummy Bad
+ * Block Markers. In the last codeword, this position contains the real BBM
+ *
+ * In order to have a consistent layout between RAW and ECC modes, we assume
+ * the following OOB layout arrangement:
+ *
+ * |-----------|  |--------------------|
+ * |yyxx.......|  |bb*********xx.......|
+ * |yyxx..ECC..|  |bb*FREEOOB*xx..ECC..|
+ * |yyxx.......|  |bb*********xx.......|
+ * |yyxx.......|  |bb*********xx.......|
+ * |-----------|  |--------------------|
+ *  first n - 1       nth OOB region
+ *  OOB regions
+ *
+ * n = Number of codewords in the page
+ * . = ECC bytes
+ * * = FREE OOB bytes
+ * y = Dummy bad block byte(s) (inaccessible when ECC enabled)
+ * x = Unused byte(s)
+ * b = Real bad block byte(s) (inaccessible when ECC enabled)
+ *
+ * This layout is read as is when ECC is disabled. When ECC is enabled, the
+ * inaccessible Bad Block byte(s) are ignored when we write to a page/oob,
+ * and assumed as 0xffs when we read a page/oob. The ECC, unused and
+ * dummy/real bad block bytes are grouped as ecc bytes (i.e, ecc->bytes is
+ * the sum of the three).
+ */
+static int qcom_nand_ooblayout_ecc(struct mtd_info *mtd, int section,
+				   struct mtd_oob_region *oobregion)
+{
+	struct nand_chip *chip = mtd_to_nand(mtd);
+	struct qcom_nand_host *host = to_qcom_nand_host(chip);
+	struct nand_ecc_ctrl *ecc = &chip->ecc;
+
+	if (section > 1)
+		return -ERANGE;
+
+	if (!section) {
+		oobregion->length = (ecc->bytes * (ecc->steps - 1)) +
+				    host->bbm_size;
+		oobregion->offset = 0;
+	} else {
+		oobregion->length = host->ecc_bytes_hw + host->spare_bytes;
+		oobregion->offset = mtd->oobsize - oobregion->length;
+	}
+
+	return 0;
+}
+
+static int qcom_nand_ooblayout_free(struct mtd_info *mtd, int section,
+				     struct mtd_oob_region *oobregion)
+{
+	struct nand_chip *chip = mtd_to_nand(mtd);
+	struct qcom_nand_host *host = to_qcom_nand_host(chip);
+	struct nand_ecc_ctrl *ecc = &chip->ecc;
+
+	if (section)
+		return -ERANGE;
+
+	oobregion->length = ecc->steps * 4;
+	oobregion->offset = ((ecc->steps - 1) * ecc->bytes) + host->bbm_size;
+
+	return 0;
+}
+
+static const struct mtd_ooblayout_ops qcom_nand_ooblayout_ops = {
+	.ecc = qcom_nand_ooblayout_ecc,
+	.free = qcom_nand_ooblayout_free,
+};
+
+static int
+qcom_nandc_calc_ecc_bytes(int step_size, int strength)
+{
+	return strength == 4 ? 12 : 16;
+}
+NAND_ECC_CAPS_SINGLE(qcom_nandc_ecc_caps, qcom_nandc_calc_ecc_bytes,
+		     NANDC_STEP_SIZE, 4, 8);
+
+static int qcom_nand_attach_chip(struct nand_chip *chip)
+{
+	struct mtd_info *mtd = nand_to_mtd(chip);
+	struct qcom_nand_host *host = to_qcom_nand_host(chip);
+	struct nand_ecc_ctrl *ecc = &chip->ecc;
+	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+	int cwperpage, bad_block_byte, ret;
+	bool wide_bus;
+	int ecc_mode = 1;
+
+	/* controller only supports 512 bytes data steps */
+	ecc->size = NANDC_STEP_SIZE;
+	wide_bus = chip->options & NAND_BUSWIDTH_16 ? true : false;
+	cwperpage = mtd->writesize / NANDC_STEP_SIZE;
+
+	/*
+	 * Each CW has 4 available OOB bytes which will be protected with ECC
+	 * so remaining bytes can be used for ECC.
+	 */
+	ret = nand_ecc_choose_conf(chip, &qcom_nandc_ecc_caps,
+				   mtd->oobsize - (cwperpage * 4));
+	if (ret) {
+		dev_err(nandc->dev, "No valid ECC settings possible\n");
+		return ret;
+	}
+
+	if (ecc->strength >= 8) {
+		/* 8 bit ECC defaults to BCH ECC on all platforms */
+		host->bch_enabled = true;
+		ecc_mode = 1;
+
+		if (wide_bus) {
+			host->ecc_bytes_hw = 14;
+			host->spare_bytes = 0;
+			host->bbm_size = 2;
+		} else {
+			host->ecc_bytes_hw = 13;
+			host->spare_bytes = 2;
+			host->bbm_size = 1;
+		}
+	} else {
+		/*
+		 * if the controller supports BCH for 4 bit ECC, the controller
+		 * uses lesser bytes for ECC. If RS is used, the ECC bytes is
+		 * always 10 bytes
+		 */
+		if (nandc->props->ecc_modes & ECC_BCH_4BIT) {
+			/* BCH */
+			host->bch_enabled = true;
+			ecc_mode = 0;
+
+			if (wide_bus) {
+				host->ecc_bytes_hw = 8;
+				host->spare_bytes = 2;
+				host->bbm_size = 2;
+			} else {
+				host->ecc_bytes_hw = 7;
+				host->spare_bytes = 4;
+				host->bbm_size = 1;
+			}
+		} else {
+			/* RS */
+			host->ecc_bytes_hw = 10;
+
+			if (wide_bus) {
+				host->spare_bytes = 0;
+				host->bbm_size = 2;
+			} else {
+				host->spare_bytes = 1;
+				host->bbm_size = 1;
+			}
+		}
+	}
+
+	/*
+	 * we consider ecc->bytes as the sum of all the non-data content in a
+	 * step. It gives us a clean representation of the oob area (even if
+	 * all the bytes aren't used for ECC).It is always 16 bytes for 8 bit
+	 * ECC and 12 bytes for 4 bit ECC
+	 */
+	ecc->bytes = host->ecc_bytes_hw + host->spare_bytes + host->bbm_size;
+
+	ecc->read_page		= qcom_nandc_read_page;
+	ecc->read_page_raw	= qcom_nandc_read_page_raw;
+	ecc->read_oob		= qcom_nandc_read_oob;
+	ecc->write_page		= qcom_nandc_write_page;
+	ecc->write_page_raw	= qcom_nandc_write_page_raw;
+	ecc->write_oob		= qcom_nandc_write_oob;
+
+	ecc->mode = NAND_ECC_HW;
+
+	mtd_set_ooblayout(mtd, &qcom_nand_ooblayout_ops);
+
+	nandc->max_cwperpage = max_t(unsigned int, nandc->max_cwperpage,
+				     cwperpage);
+
+	/*
+	 * DATA_UD_BYTES varies based on whether the read/write command protects
+	 * spare data with ECC too. We protect spare data by default, so we set
+	 * it to main + spare data, which are 512 and 4 bytes respectively.
+	 */
+	host->cw_data = 516;
+
+	/*
+	 * total bytes in a step, either 528 bytes for 4 bit ECC, or 532 bytes
+	 * for 8 bit ECC
+	 */
+	host->cw_size = host->cw_data + ecc->bytes;
+	bad_block_byte = mtd->writesize - host->cw_size * (cwperpage - 1) + 1;
+
+	host->cfg0 = (cwperpage - 1) << CW_PER_PAGE
+				| host->cw_data << UD_SIZE_BYTES
+				| 0 << DISABLE_STATUS_AFTER_WRITE
+				| 5 << NUM_ADDR_CYCLES
+				| host->ecc_bytes_hw << ECC_PARITY_SIZE_BYTES_RS
+				| 0 << STATUS_BFR_READ
+				| 1 << SET_RD_MODE_AFTER_STATUS
+				| host->spare_bytes << SPARE_SIZE_BYTES;
+
+	host->cfg1 = 7 << NAND_RECOVERY_CYCLES
+				| 0 <<  CS_ACTIVE_BSY
+				| bad_block_byte << BAD_BLOCK_BYTE_NUM
+				| 0 << BAD_BLOCK_IN_SPARE_AREA
+				| 2 << WR_RD_BSY_GAP
+				| wide_bus << WIDE_FLASH
+				| host->bch_enabled << ENABLE_BCH_ECC;
+
+	host->cfg0_raw = (cwperpage - 1) << CW_PER_PAGE
+				| host->cw_size << UD_SIZE_BYTES
+				| 5 << NUM_ADDR_CYCLES
+				| 0 << SPARE_SIZE_BYTES;
+
+	host->cfg1_raw = 7 << NAND_RECOVERY_CYCLES
+				| 0 << CS_ACTIVE_BSY
+				| 17 << BAD_BLOCK_BYTE_NUM
+				| 1 << BAD_BLOCK_IN_SPARE_AREA
+				| 2 << WR_RD_BSY_GAP
+				| wide_bus << WIDE_FLASH
+				| 1 << DEV0_CFG1_ECC_DISABLE;
+
+	host->ecc_bch_cfg = !host->bch_enabled << ECC_CFG_ECC_DISABLE
+				| 0 << ECC_SW_RESET
+				| host->cw_data << ECC_NUM_DATA_BYTES
+				| 1 << ECC_FORCE_CLK_OPEN
+				| ecc_mode << ECC_MODE
+				| host->ecc_bytes_hw << ECC_PARITY_SIZE_BYTES_BCH;
+
+	host->ecc_buf_cfg = 0x203 << NUM_STEPS;
+
+	host->clrflashstatus = FS_READY_BSY_N;
+	host->clrreadstatus = 0xc0;
+	nandc->regs->erased_cw_detect_cfg_clr =
+		cpu_to_le32(CLR_ERASED_PAGE_DET);
+	nandc->regs->erased_cw_detect_cfg_set =
+		cpu_to_le32(SET_ERASED_PAGE_DET);
+
+	dev_dbg(nandc->dev,
+		"cfg0 %x cfg1 %x ecc_buf_cfg %x ecc_bch cfg %x cw_size %d cw_data %d strength %d parity_bytes %d steps %d\n",
+		host->cfg0, host->cfg1, host->ecc_buf_cfg, host->ecc_bch_cfg,
+		host->cw_size, host->cw_data, ecc->strength, ecc->bytes,
+		cwperpage);
+
+	return 0;
+}
+
+static const struct nand_controller_ops qcom_nandc_ops = {
+	.attach_chip = qcom_nand_attach_chip,
+};
+
+static int qcom_nandc_alloc(struct qcom_nand_controller *nandc)
+{
+	int ret;
+
+	ret = dma_set_coherent_mask(nandc->dev, DMA_BIT_MASK(32));
+	if (ret) {
+		dev_err(nandc->dev, "failed to set DMA mask\n");
+		return ret;
+	}
+
+	/*
+	 * we use the internal buffer for reading ONFI params, reading small
+	 * data like ID and status, and preforming read-copy-write operations
+	 * when writing to a codeword partially. 532 is the maximum possible
+	 * size of a codeword for our nand controller
+	 */
+	nandc->buf_size = 532;
+
+	nandc->data_buffer = devm_kzalloc(nandc->dev, nandc->buf_size,
+					GFP_KERNEL);
+	if (!nandc->data_buffer)
+		return -ENOMEM;
+
+	nandc->regs = devm_kzalloc(nandc->dev, sizeof(*nandc->regs),
+					GFP_KERNEL);
+	if (!nandc->regs)
+		return -ENOMEM;
+
+	nandc->reg_read_buf = devm_kcalloc(nandc->dev,
+				MAX_REG_RD, sizeof(*nandc->reg_read_buf),
+				GFP_KERNEL);
+	if (!nandc->reg_read_buf)
+		return -ENOMEM;
+
+	if (nandc->props->is_bam) {
+		nandc->reg_read_dma =
+			dma_map_single(nandc->dev, nandc->reg_read_buf,
+				       MAX_REG_RD *
+				       sizeof(*nandc->reg_read_buf),
+				       DMA_FROM_DEVICE);
+		if (dma_mapping_error(nandc->dev, nandc->reg_read_dma)) {
+			dev_err(nandc->dev, "failed to DMA MAP reg buffer\n");
+			return -EIO;
+		}
+
+		nandc->tx_chan = dma_request_slave_channel(nandc->dev, "tx");
+		if (!nandc->tx_chan) {
+			dev_err(nandc->dev, "failed to request tx channel\n");
+			return -ENODEV;
+		}
+
+		nandc->rx_chan = dma_request_slave_channel(nandc->dev, "rx");
+		if (!nandc->rx_chan) {
+			dev_err(nandc->dev, "failed to request rx channel\n");
+			return -ENODEV;
+		}
+
+		nandc->cmd_chan = dma_request_slave_channel(nandc->dev, "cmd");
+		if (!nandc->cmd_chan) {
+			dev_err(nandc->dev, "failed to request cmd channel\n");
+			return -ENODEV;
+		}
+
+		/*
+		 * Initially allocate BAM transaction to read ONFI param page.
+		 * After detecting all the devices, this BAM transaction will
+		 * be freed and the next BAM tranasction will be allocated with
+		 * maximum codeword size
+		 */
+		nandc->max_cwperpage = 1;
+		nandc->bam_txn = alloc_bam_transaction(nandc);
+		if (!nandc->bam_txn) {
+			dev_err(nandc->dev,
+				"failed to allocate bam transaction\n");
+			return -ENOMEM;
+		}
+	} else {
+		nandc->chan = dma_request_slave_channel(nandc->dev, "rxtx");
+		if (!nandc->chan) {
+			dev_err(nandc->dev,
+				"failed to request slave channel\n");
+			return -ENODEV;
+		}
+	}
+
+	INIT_LIST_HEAD(&nandc->desc_list);
+	INIT_LIST_HEAD(&nandc->host_list);
+
+	nand_controller_init(&nandc->controller);
+	nandc->controller.ops = &qcom_nandc_ops;
+
+	return 0;
+}
+
+static void qcom_nandc_unalloc(struct qcom_nand_controller *nandc)
+{
+	if (nandc->props->is_bam) {
+		if (!dma_mapping_error(nandc->dev, nandc->reg_read_dma))
+			dma_unmap_single(nandc->dev, nandc->reg_read_dma,
+					 MAX_REG_RD *
+					 sizeof(*nandc->reg_read_buf),
+					 DMA_FROM_DEVICE);
+
+		if (nandc->tx_chan)
+			dma_release_channel(nandc->tx_chan);
+
+		if (nandc->rx_chan)
+			dma_release_channel(nandc->rx_chan);
+
+		if (nandc->cmd_chan)
+			dma_release_channel(nandc->cmd_chan);
+	} else {
+		if (nandc->chan)
+			dma_release_channel(nandc->chan);
+	}
+}
+
+/* one time setup of a few nand controller registers */
+static int qcom_nandc_setup(struct qcom_nand_controller *nandc)
+{
+	u32 nand_ctrl;
+
+	/* kill onenand */
+	if (!nandc->props->is_qpic)
+		nandc_write(nandc, SFLASHC_BURST_CFG, 0);
+	nandc_write(nandc, dev_cmd_reg_addr(nandc, NAND_DEV_CMD_VLD),
+		    NAND_DEV_CMD_VLD_VAL);
+
+	/* enable ADM or BAM DMA */
+	if (nandc->props->is_bam) {
+		nand_ctrl = nandc_read(nandc, NAND_CTRL);
+		nandc_write(nandc, NAND_CTRL, nand_ctrl | BAM_MODE_EN);
+	} else {
+		nandc_write(nandc, NAND_FLASH_CHIP_SELECT, DM_EN);
+	}
+
+	/* save the original values of these registers */
+	nandc->cmd1 = nandc_read(nandc, dev_cmd_reg_addr(nandc, NAND_DEV_CMD1));
+	nandc->vld = NAND_DEV_CMD_VLD_VAL;
+
+	return 0;
+}
+
+static int qcom_nand_host_init_and_register(struct qcom_nand_controller *nandc,
+					    struct qcom_nand_host *host,
+					    struct device_node *dn)
+{
+	struct nand_chip *chip = &host->chip;
+	struct mtd_info *mtd = nand_to_mtd(chip);
+	struct device *dev = nandc->dev;
+	int ret;
+
+	ret = of_property_read_u32(dn, "reg", &host->cs);
+	if (ret) {
+		dev_err(dev, "can't get chip-select\n");
+		return -ENXIO;
+	}
+
+	nand_set_flash_node(chip, dn);
+	mtd->name = devm_kasprintf(dev, GFP_KERNEL, "qcom_nand.%d", host->cs);
+	if (!mtd->name)
+		return -ENOMEM;
+
+	mtd->owner = THIS_MODULE;
+	mtd->dev.parent = dev;
+
+	chip->cmdfunc		= qcom_nandc_command;
+	chip->select_chip	= qcom_nandc_select_chip;
+	chip->read_byte		= qcom_nandc_read_byte;
+	chip->read_buf		= qcom_nandc_read_buf;
+	chip->write_buf		= qcom_nandc_write_buf;
+	chip->set_features	= nand_get_set_features_notsupp;
+	chip->get_features	= nand_get_set_features_notsupp;
+
+	/*
+	 * the bad block marker is readable only when we read the last codeword
+	 * of a page with ECC disabled. currently, the nand_base and nand_bbt
+	 * helpers don't allow us to read BB from a nand chip with ECC
+	 * disabled (MTD_OPS_PLACE_OOB is set by default). use the block_bad
+	 * and block_markbad helpers until we permanently switch to using
+	 * MTD_OPS_RAW for all drivers (with the help of badblockbits)
+	 */
+	chip->block_bad		= qcom_nandc_block_bad;
+	chip->block_markbad	= qcom_nandc_block_markbad;
+
+	chip->controller = &nandc->controller;
+	chip->options |= NAND_NO_SUBPAGE_WRITE | NAND_USE_BOUNCE_BUFFER |
+			 NAND_SKIP_BBTSCAN;
+
+	/* set up initial status value */
+	host->status = NAND_STATUS_READY | NAND_STATUS_WP;
+
+	ret = nand_scan(chip, 1);
+	if (ret)
+		return ret;
+
+	if (nandc->props->is_bam) {
+		free_bam_transaction(nandc);
+		nandc->bam_txn = alloc_bam_transaction(nandc);
+		if (!nandc->bam_txn) {
+			dev_err(nandc->dev,
+				"failed to allocate bam transaction\n");
+			return -ENOMEM;
+		}
+	}
+
+	ret = mtd_device_register(mtd, NULL, 0);
+	if (ret)
+		nand_cleanup(chip);
+
+	return ret;
+}
+
+static int qcom_probe_nand_devices(struct qcom_nand_controller *nandc)
+{
+	struct device *dev = nandc->dev;
+	struct device_node *dn = dev->of_node, *child;
+	struct qcom_nand_host *host;
+	int ret = -ENODEV;
+
+	for_each_available_child_of_node(dn, child) {
+		host = devm_kzalloc(dev, sizeof(*host), GFP_KERNEL);
+		if (!host) {
+			of_node_put(child);
+			return -ENOMEM;
+		}
+
+		ret = qcom_nand_host_init_and_register(nandc, host, child);
+		if (ret) {
+			devm_kfree(dev, host);
+			continue;
+		}
+
+		list_add_tail(&host->node, &nandc->host_list);
+	}
+
+	return ret;
+}
+
+/* parse custom DT properties here */
+static int qcom_nandc_parse_dt(struct platform_device *pdev)
+{
+	struct qcom_nand_controller *nandc = platform_get_drvdata(pdev);
+	struct device_node *np = nandc->dev->of_node;
+	int ret;
+
+	if (!nandc->props->is_bam) {
+		ret = of_property_read_u32(np, "qcom,cmd-crci",
+					   &nandc->cmd_crci);
+		if (ret) {
+			dev_err(nandc->dev, "command CRCI unspecified\n");
+			return ret;
+		}
+
+		ret = of_property_read_u32(np, "qcom,data-crci",
+					   &nandc->data_crci);
+		if (ret) {
+			dev_err(nandc->dev, "data CRCI unspecified\n");
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int qcom_nandc_probe(struct platform_device *pdev)
+{
+	struct qcom_nand_controller *nandc;
+	const void *dev_data;
+	struct device *dev = &pdev->dev;
+	struct resource *res;
+	int ret;
+
+	nandc = devm_kzalloc(&pdev->dev, sizeof(*nandc), GFP_KERNEL);
+	if (!nandc)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, nandc);
+	nandc->dev = dev;
+
+	dev_data = of_device_get_match_data(dev);
+	if (!dev_data) {
+		dev_err(&pdev->dev, "failed to get device data\n");
+		return -ENODEV;
+	}
+
+	nandc->props = dev_data;
+
+	nandc->core_clk = devm_clk_get(dev, "core");
+	if (IS_ERR(nandc->core_clk))
+		return PTR_ERR(nandc->core_clk);
+
+	nandc->aon_clk = devm_clk_get(dev, "aon");
+	if (IS_ERR(nandc->aon_clk))
+		return PTR_ERR(nandc->aon_clk);
+
+	ret = qcom_nandc_parse_dt(pdev);
+	if (ret)
+		return ret;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	nandc->base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(nandc->base))
+		return PTR_ERR(nandc->base);
+
+	nandc->base_phys = res->start;
+	nandc->base_dma = dma_map_resource(dev, res->start,
+					   resource_size(res),
+					   DMA_BIDIRECTIONAL, 0);
+	if (!nandc->base_dma)
+		return -ENXIO;
+
+	ret = clk_prepare_enable(nandc->core_clk);
+	if (ret)
+		goto err_core_clk;
+
+	ret = clk_prepare_enable(nandc->aon_clk);
+	if (ret)
+		goto err_aon_clk;
+
+	ret = qcom_nandc_alloc(nandc);
+	if (ret)
+		goto err_nandc_alloc;
+
+	ret = qcom_nandc_setup(nandc);
+	if (ret)
+		goto err_setup;
+
+	ret = qcom_probe_nand_devices(nandc);
+	if (ret)
+		goto err_setup;
+
+	return 0;
+
+err_setup:
+	qcom_nandc_unalloc(nandc);
+err_nandc_alloc:
+	clk_disable_unprepare(nandc->aon_clk);
+err_aon_clk:
+	clk_disable_unprepare(nandc->core_clk);
+err_core_clk:
+	dma_unmap_resource(dev, res->start, resource_size(res),
+			   DMA_BIDIRECTIONAL, 0);
+	return ret;
+}
+
+static int qcom_nandc_remove(struct platform_device *pdev)
+{
+	struct qcom_nand_controller *nandc = platform_get_drvdata(pdev);
+	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	struct qcom_nand_host *host;
+
+	list_for_each_entry(host, &nandc->host_list, node)
+		nand_release(&host->chip);
+
+
+	qcom_nandc_unalloc(nandc);
+
+	clk_disable_unprepare(nandc->aon_clk);
+	clk_disable_unprepare(nandc->core_clk);
+
+	dma_unmap_resource(&pdev->dev, nandc->base_dma, resource_size(res),
+			   DMA_BIDIRECTIONAL, 0);
+
+	return 0;
+}
+
+static const struct qcom_nandc_props ipq806x_nandc_props = {
+	.ecc_modes = (ECC_RS_4BIT | ECC_BCH_8BIT),
+	.is_bam = false,
+	.dev_cmd_reg_start = 0x0,
+};
+
+static const struct qcom_nandc_props ipq4019_nandc_props = {
+	.ecc_modes = (ECC_BCH_4BIT | ECC_BCH_8BIT),
+	.is_bam = true,
+	.is_qpic = true,
+	.dev_cmd_reg_start = 0x0,
+};
+
+static const struct qcom_nandc_props ipq8074_nandc_props = {
+	.ecc_modes = (ECC_BCH_4BIT | ECC_BCH_8BIT),
+	.is_bam = true,
+	.is_qpic = true,
+	.dev_cmd_reg_start = 0x7000,
+};
+
+/*
+ * data will hold a struct pointer containing more differences once we support
+ * more controller variants
+ */
+static const struct of_device_id qcom_nandc_of_match[] = {
+	{
+		.compatible = "qcom,ipq806x-nand",
+		.data = &ipq806x_nandc_props,
+	},
+	{
+		.compatible = "qcom,ipq4019-nand",
+		.data = &ipq4019_nandc_props,
+	},
+	{
+		.compatible = "qcom,ipq8074-nand",
+		.data = &ipq8074_nandc_props,
+	},
+	{}
+};
+MODULE_DEVICE_TABLE(of, qcom_nandc_of_match);
+
+static struct platform_driver qcom_nandc_driver = {
+	.driver = {
+		.name = "qcom-nandc",
+		.of_match_table = qcom_nandc_of_match,
+	},
+	.probe   = qcom_nandc_probe,
+	.remove  = qcom_nandc_remove,
+};
+module_platform_driver(qcom_nandc_driver);
+
+MODULE_AUTHOR("Archit Taneja <architt@codeaurora.org>");
+MODULE_DESCRIPTION("Qualcomm NAND Controller driver");
+MODULE_LICENSE("GPL v2");