Merge tag 'io_uring-5.11-2021-01-16' of git://git.kernel.dk/linux-block

[linux/fpc-iii.git] / drivers / mtd / nand / raw / marvell_nand.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Marvell NAND flash controller driver
 *
 * Copyright (C) 2017 Marvell
 * Author: Miquel RAYNAL <miquel.raynal@free-electrons.com>
 *
 *
 * This NAND controller driver handles two versions of the hardware,
 * one is called NFCv1 and is available on PXA SoCs and the other is
 * called NFCv2 and is available on Armada SoCs.
 *
 * The main visible difference is that NFCv1 only has Hamming ECC
 * capabilities, while NFCv2 also embeds a BCH ECC engine. Also, DMA
 * is not used with NFCv2.
 *
 * The ECC layouts are depicted in details in Marvell AN-379, but here
 * is a brief description.
 *
 * When using Hamming, the data is split in 512B chunks (either 1, 2
 * or 4) and each chunk will have its own ECC "digest" of 6B at the
 * beginning of the OOB area and eventually the remaining free OOB
 * bytes (also called "spare" bytes in the driver). This engine
 * corrects up to 1 bit per chunk and detects reliably an error if
 * there are at most 2 bitflips. Here is the page layout used by the
 * controller when Hamming is chosen:
 *
 * +-------------------------------------------------------------+
 * | Data 1 | ... | Data N | ECC 1 | ... | ECCN | Free OOB bytes |
 * +-------------------------------------------------------------+
 *
 * When using the BCH engine, there are N identical (data + free OOB +
 * ECC) sections and potentially an extra one to deal with
 * configurations where the chosen (data + free OOB + ECC) sizes do
 * not align with the page (data + OOB) size. ECC bytes are always
 * 30B per ECC chunk. Here is the page layout used by the controller
 * when BCH is chosen:
 *
 * +-----------------------------------------
 * | Data 1 | Free OOB bytes 1 | ECC 1 | ...
 * +-----------------------------------------
 *
 *      -------------------------------------------
 *       ... | Data N | Free OOB bytes N | ECC N |
 *      -------------------------------------------
 *
 *           --------------------------------------------+
 *            Last Data | Last Free OOB bytes | Last ECC |
 *           --------------------------------------------+
 *
 * In both cases, the layout seen by the user is always: all data
 * first, then all free OOB bytes and finally all ECC bytes. With BCH,
 * ECC bytes are 30B long and are padded with 0xFF to align on 32
 * bytes.
 *
 * The controller has certain limitations that are handled by the
 * driver:
 *   - It can only read 2k at a time. To overcome this limitation, the
 *     driver issues data cycles on the bus, without issuing new
 *     CMD + ADDR cycles. The Marvell term is "naked" operations.
 *   - The ECC strength in BCH mode cannot be tuned. It is fixed 16
 *     bits. What can be tuned is the ECC block size as long as it
 *     stays between 512B and 2kiB. It's usually chosen based on the
 *     chip ECC requirements. For instance, using 2kiB ECC chunks
 *     provides 4b/512B correctability.
 *   - The controller will always treat data bytes, free OOB bytes
 *     and ECC bytes in that order, no matter what the real layout is
 *     (which is usually all data then all OOB bytes). The
 *     marvell_nfc_layouts array below contains the currently
 *     supported layouts.
 *   - Because of these weird layouts, the Bad Block Markers can be
 *     located in data section. In this case, the NAND_BBT_NO_OOB_BBM
 *     option must be set to prevent scanning/writing bad block
 *     markers.
 */

#include <linux/module.h>
#include <linux/clk.h>
#include <linux/mtd/rawnand.h>
#include <linux/of_platform.h>
#include <linux/iopoll.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>
#include <asm/unaligned.h>

#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/dma/pxa-dma.h>
#include <linux/platform_data/mtd-nand-pxa3xx.h>

/* Data FIFO granularity, FIFO reads/writes must be a multiple of this length */
#define FIFO_DEPTH              8
#define FIFO_REP(x)             (x / sizeof(u32))
#define BCH_SEQ_READS           (32 / FIFO_DEPTH)
/* NFC does not support transfers of larger chunks at a time */
#define MAX_CHUNK_SIZE          2112
/* NFCv1 cannot read more that 7 bytes of ID */
#define NFCV1_READID_LEN        7
/* Polling is done at a pace of POLL_PERIOD us until POLL_TIMEOUT is reached */
#define POLL_PERIOD             0
#define POLL_TIMEOUT            100000
/* Interrupt maximum wait period in ms */
#define IRQ_TIMEOUT             1000
/* Latency in clock cycles between SoC pins and NFC logic */
#define MIN_RD_DEL_CNT          3
/* Maximum number of contiguous address cycles */
#define MAX_ADDRESS_CYC_NFCV1   5
#define MAX_ADDRESS_CYC_NFCV2   7
/* System control registers/bits to enable the NAND controller on some SoCs */
#define GENCONF_SOC_DEVICE_MUX  0x208
#define GENCONF_SOC_DEVICE_MUX_NFC_EN BIT(0)
#define GENCONF_SOC_DEVICE_MUX_ECC_CLK_RST BIT(20)
#define GENCONF_SOC_DEVICE_MUX_ECC_CORE_RST BIT(21)
#define GENCONF_SOC_DEVICE_MUX_NFC_INT_EN BIT(25)
#define GENCONF_CLK_GATING_CTRL 0x220
#define GENCONF_CLK_GATING_CTRL_ND_GATE BIT(2)
#define GENCONF_ND_CLK_CTRL     0x700
#define GENCONF_ND_CLK_CTRL_EN  BIT(0)

/* NAND controller data flash control register */
#define NDCR                    0x00
#define NDCR_ALL_INT            GENMASK(11, 0)
#define NDCR_CS1_CMDDM          BIT(7)
#define NDCR_CS0_CMDDM          BIT(8)
#define NDCR_RDYM               BIT(11)
#define NDCR_ND_ARB_EN          BIT(12)
#define NDCR_RA_START           BIT(15)
#define NDCR_RD_ID_CNT(x)       (min_t(unsigned int, x, 0x7) << 16)
#define NDCR_PAGE_SZ(x)         (x >= 2048 ? BIT(24) : 0)
#define NDCR_DWIDTH_M           BIT(26)
#define NDCR_DWIDTH_C           BIT(27)
#define NDCR_ND_RUN             BIT(28)
#define NDCR_DMA_EN             BIT(29)
#define NDCR_ECC_EN             BIT(30)
#define NDCR_SPARE_EN           BIT(31)
#define NDCR_GENERIC_FIELDS_MASK (~(NDCR_RA_START | NDCR_PAGE_SZ(2048) | \
                                    NDCR_DWIDTH_M | NDCR_DWIDTH_C))

/* NAND interface timing parameter 0 register */
#define NDTR0                   0x04
#define NDTR0_TRP(x)            ((min_t(unsigned int, x, 0xF) & 0x7) << 0)
#define NDTR0_TRH(x)            (min_t(unsigned int, x, 0x7) << 3)
#define NDTR0_ETRP(x)           ((min_t(unsigned int, x, 0xF) & 0x8) << 3)
#define NDTR0_SEL_NRE_EDGE      BIT(7)
#define NDTR0_TWP(x)            (min_t(unsigned int, x, 0x7) << 8)
#define NDTR0_TWH(x)            (min_t(unsigned int, x, 0x7) << 11)
#define NDTR0_TCS(x)            (min_t(unsigned int, x, 0x7) << 16)
#define NDTR0_TCH(x)            (min_t(unsigned int, x, 0x7) << 19)
#define NDTR0_RD_CNT_DEL(x)     (min_t(unsigned int, x, 0xF) << 22)
#define NDTR0_SELCNTR           BIT(26)
#define NDTR0_TADL(x)           (min_t(unsigned int, x, 0x1F) << 27)

/* NAND interface timing parameter 1 register */
#define NDTR1                   0x0C
#define NDTR1_TAR(x)            (min_t(unsigned int, x, 0xF) << 0)
#define NDTR1_TWHR(x)           (min_t(unsigned int, x, 0xF) << 4)
#define NDTR1_TRHW(x)           (min_t(unsigned int, x / 16, 0x3) << 8)
#define NDTR1_PRESCALE          BIT(14)
#define NDTR1_WAIT_MODE         BIT(15)
#define NDTR1_TR(x)             (min_t(unsigned int, x, 0xFFFF) << 16)

/* NAND controller status register */
#define NDSR                    0x14
#define NDSR_WRCMDREQ           BIT(0)
#define NDSR_RDDREQ             BIT(1)
#define NDSR_WRDREQ             BIT(2)
#define NDSR_CORERR             BIT(3)
#define NDSR_UNCERR             BIT(4)
#define NDSR_CMDD(cs)           BIT(8 - cs)
#define NDSR_RDY(rb)            BIT(11 + rb)
#define NDSR_ERRCNT(x)          ((x >> 16) & 0x1F)

/* NAND ECC control register */
#define NDECCCTRL               0x28
#define NDECCCTRL_BCH_EN        BIT(0)

/* NAND controller data buffer register */
#define NDDB                    0x40

/* NAND controller command buffer 0 register */
#define NDCB0                   0x48
#define NDCB0_CMD1(x)           ((x & 0xFF) << 0)
#define NDCB0_CMD2(x)           ((x & 0xFF) << 8)
#define NDCB0_ADDR_CYC(x)       ((x & 0x7) << 16)
#define NDCB0_ADDR_GET_NUM_CYC(x) (((x) >> 16) & 0x7)
#define NDCB0_DBC               BIT(19)
#define NDCB0_CMD_TYPE(x)       ((x & 0x7) << 21)
#define NDCB0_CSEL              BIT(24)
#define NDCB0_RDY_BYP           BIT(27)
#define NDCB0_LEN_OVRD          BIT(28)
#define NDCB0_CMD_XTYPE(x)      ((x & 0x7) << 29)

/* NAND controller command buffer 1 register */
#define NDCB1                   0x4C
#define NDCB1_COLS(x)           ((x & 0xFFFF) << 0)
#define NDCB1_ADDRS_PAGE(x)     (x << 16)

/* NAND controller command buffer 2 register */
#define NDCB2                   0x50
#define NDCB2_ADDR5_PAGE(x)     (((x >> 16) & 0xFF) << 0)
#define NDCB2_ADDR5_CYC(x)      ((x & 0xFF) << 0)

/* NAND controller command buffer 3 register */
#define NDCB3                   0x54
#define NDCB3_ADDR6_CYC(x)      ((x & 0xFF) << 16)
#define NDCB3_ADDR7_CYC(x)      ((x & 0xFF) << 24)

/* NAND controller command buffer 0 register 'type' and 'xtype' fields */
#define TYPE_READ               0
#define TYPE_WRITE              1
#define TYPE_ERASE              2
#define TYPE_READ_ID            3
#define TYPE_STATUS             4
#define TYPE_RESET              5
#define TYPE_NAKED_CMD          6
#define TYPE_NAKED_ADDR         7
#define TYPE_MASK               7
#define XTYPE_MONOLITHIC_RW     0
#define XTYPE_LAST_NAKED_RW     1
#define XTYPE_FINAL_COMMAND     3
#define XTYPE_READ              4
#define XTYPE_WRITE_DISPATCH    4
#define XTYPE_NAKED_RW          5
#define XTYPE_COMMAND_DISPATCH  6
#define XTYPE_MASK              7

/**
 * struct marvell_hw_ecc_layout - layout of Marvell ECC
 *
 * Marvell ECC engine works differently than the others, in order to limit the
 * size of the IP, hardware engineers chose to set a fixed strength at 16 bits
 * per subpage, and depending on a the desired strength needed by the NAND chip,
 * a particular layout mixing data/spare/ecc is defined, with a possible last
 * chunk smaller that the others.
 *
 * @writesize:          Full page size on which the layout applies
 * @chunk:              Desired ECC chunk size on which the layout applies
 * @strength:           Desired ECC strength (per chunk size bytes) on which the
 *                      layout applies
 * @nchunks:            Total number of chunks
 * @full_chunk_cnt:     Number of full-sized chunks, which is the number of
 *                      repetitions of the pattern:
 *                      (data_bytes + spare_bytes + ecc_bytes).
 * @data_bytes:         Number of data bytes per chunk
 * @spare_bytes:        Number of spare bytes per chunk
 * @ecc_bytes:          Number of ecc bytes per chunk
 * @last_data_bytes:    Number of data bytes in the last chunk
 * @last_spare_bytes:   Number of spare bytes in the last chunk
 * @last_ecc_bytes:     Number of ecc bytes in the last chunk
 */
struct marvell_hw_ecc_layout {
        /* Constraints */
        int writesize;
        int chunk;
        int strength;
        /* Corresponding layout */
        int nchunks;
        int full_chunk_cnt;
        int data_bytes;
        int spare_bytes;
        int ecc_bytes;
        int last_data_bytes;
        int last_spare_bytes;
        int last_ecc_bytes;
};

#define MARVELL_LAYOUT(ws, dc, ds, nc, fcc, db, sb, eb, ldb, lsb, leb)  \
        {                                                               \
                .writesize = ws,                                        \
                .chunk = dc,                                            \
                .strength = ds,                                         \
                .nchunks = nc,                                          \
                .full_chunk_cnt = fcc,                                  \
                .data_bytes = db,                                       \
                .spare_bytes = sb,                                      \
                .ecc_bytes = eb,                                        \
                .last_data_bytes = ldb,                                 \
                .last_spare_bytes = lsb,                                \
                .last_ecc_bytes = leb,                                  \
        }

/* Layouts explained in AN-379_Marvell_SoC_NFC_ECC */
static const struct marvell_hw_ecc_layout marvell_nfc_layouts[] = {
        MARVELL_LAYOUT(  512,   512,  1,  1,  1,  512,  8,  8,  0,  0,  0),
        MARVELL_LAYOUT( 2048,   512,  1,  1,  1, 2048, 40, 24,  0,  0,  0),
        MARVELL_LAYOUT( 2048,   512,  4,  1,  1, 2048, 32, 30,  0,  0,  0),
        MARVELL_LAYOUT( 2048,   512,  8,  2,  1, 1024,  0, 30,1024,32, 30),
        MARVELL_LAYOUT( 4096,   512,  4,  2,  2, 2048, 32, 30,  0,  0,  0),
        MARVELL_LAYOUT( 4096,   512,  8,  5,  4, 1024,  0, 30,  0, 64, 30),
        MARVELL_LAYOUT( 8192,   512,  4,  4,  4, 2048,  0, 30,  0,  0,  0),
        MARVELL_LAYOUT( 8192,   512,  8,  9,  8, 1024,  0, 30,  0, 160, 30),
};

/**
 * struct marvell_nand_chip_sel - CS line description
 *
 * The Nand Flash Controller has up to 4 CE and 2 RB pins. The CE selection
 * is made by a field in NDCB0 register, and in another field in NDCB2 register.
 * The datasheet describes the logic with an error: ADDR5 field is once
 * declared at the beginning of NDCB2, and another time at its end. Because the
 * ADDR5 field of NDCB2 may be used by other bytes, it would be more logical
 * to use the last bit of this field instead of the first ones.
 *
 * @cs:                 Wanted CE lane.
 * @ndcb0_csel:         Value of the NDCB0 register with or without the flag
 *                      selecting the wanted CE lane. This is set once when
 *                      the Device Tree is probed.
 * @rb:                 Ready/Busy pin for the flash chip
 */
struct marvell_nand_chip_sel {
        unsigned int cs;
        u32 ndcb0_csel;
        unsigned int rb;
};

/**
 * struct marvell_nand_chip - stores NAND chip device related information
 *
 * @chip:               Base NAND chip structure
 * @node:               Used to store NAND chips into a list
 * @layout:             NAND layout when using hardware ECC
 * @ndcr:               Controller register value for this NAND chip
 * @ndtr0:              Timing registers 0 value for this NAND chip
 * @ndtr1:              Timing registers 1 value for this NAND chip
 * @addr_cyc:           Amount of cycles needed to pass column address
 * @selected_die:       Current active CS
 * @nsels:              Number of CS lines required by the NAND chip
 * @sels:               Array of CS lines descriptions
 */
struct marvell_nand_chip {
        struct nand_chip chip;
        struct list_head node;
        const struct marvell_hw_ecc_layout *layout;
        u32 ndcr;
        u32 ndtr0;
        u32 ndtr1;
        int addr_cyc;
        int selected_die;
        unsigned int nsels;
        struct marvell_nand_chip_sel sels[];
};

static inline struct marvell_nand_chip *to_marvell_nand(struct nand_chip *chip)
{
        return container_of(chip, struct marvell_nand_chip, chip);
}

static inline struct marvell_nand_chip_sel *to_nand_sel(struct marvell_nand_chip
                                                        *nand)
{
        return &nand->sels[nand->selected_die];
}

/**
 * struct marvell_nfc_caps - NAND controller capabilities for distinction
 *                           between compatible strings
 *
 * @max_cs_nb:          Number of Chip Select lines available
 * @max_rb_nb:          Number of Ready/Busy lines available
 * @need_system_controller: Indicates if the SoC needs to have access to the
 *                      system controller (ie. to enable the NAND controller)
 * @legacy_of_bindings: Indicates if DT parsing must be done using the old
 *                      fashion way
 * @is_nfcv2:           NFCv2 has numerous enhancements compared to NFCv1, ie.
 *                      BCH error detection and correction algorithm,
 *                      NDCB3 register has been added
 * @use_dma:            Use dma for data transfers
 */
struct marvell_nfc_caps {
        unsigned int max_cs_nb;
        unsigned int max_rb_nb;
        bool need_system_controller;
        bool legacy_of_bindings;
        bool is_nfcv2;
        bool use_dma;
};

/**
 * struct marvell_nfc - stores Marvell NAND controller information
 *
 * @controller:         Base controller structure
 * @dev:                Parent device (used to print error messages)
 * @regs:               NAND controller registers
 * @core_clk:           Core clock
 * @reg_clk:            Registers clock
 * @complete:           Completion object to wait for NAND controller events
 * @assigned_cs:        Bitmask describing already assigned CS lines
 * @chips:              List containing all the NAND chips attached to
 *                      this NAND controller
 * @selected_chip:      Currently selected target chip
 * @caps:               NAND controller capabilities for each compatible string
 * @use_dma:            Whetner DMA is used
 * @dma_chan:           DMA channel (NFCv1 only)
 * @dma_buf:            32-bit aligned buffer for DMA transfers (NFCv1 only)
 */
struct marvell_nfc {
        struct nand_controller controller;
        struct device *dev;
        void __iomem *regs;
        struct clk *core_clk;
        struct clk *reg_clk;
        struct completion complete;
        unsigned long assigned_cs;
        struct list_head chips;
        struct nand_chip *selected_chip;
        const struct marvell_nfc_caps *caps;

        /* DMA (NFCv1 only) */
        bool use_dma;
        struct dma_chan *dma_chan;
        u8 *dma_buf;
};

static inline struct marvell_nfc *to_marvell_nfc(struct nand_controller *ctrl)
{
        return container_of(ctrl, struct marvell_nfc, controller);
}

/**
 * struct marvell_nfc_timings - NAND controller timings expressed in NAND
 *                              Controller clock cycles
 *
 * @tRP:                ND_nRE pulse width
 * @tRH:                ND_nRE high duration
 * @tWP:                ND_nWE pulse time
 * @tWH:                ND_nWE high duration
 * @tCS:                Enable signal setup time
 * @tCH:                Enable signal hold time
 * @tADL:               Address to write data delay
 * @tAR:                ND_ALE low to ND_nRE low delay
 * @tWHR:               ND_nWE high to ND_nRE low for status read
 * @tRHW:               ND_nRE high duration, read to write delay
 * @tR:                 ND_nWE high to ND_nRE low for read
 */
struct marvell_nfc_timings {
        /* NDTR0 fields */
        unsigned int tRP;
        unsigned int tRH;
        unsigned int tWP;
        unsigned int tWH;
        unsigned int tCS;
        unsigned int tCH;
        unsigned int tADL;
        /* NDTR1 fields */
        unsigned int tAR;
        unsigned int tWHR;
        unsigned int tRHW;
        unsigned int tR;
};

/**
 * Derives a duration in numbers of clock cycles.
 *
 * @ps: Duration in pico-seconds
 * @period_ns:  Clock period in nano-seconds
 *
 * Convert the duration in nano-seconds, then divide by the period and
 * return the number of clock periods.
 */
#define TO_CYCLES(ps, period_ns) (DIV_ROUND_UP(ps / 1000, period_ns))
#define TO_CYCLES64(ps, period_ns) (DIV_ROUND_UP_ULL(div_u64(ps, 1000), \
                                                     period_ns))

/**
 * struct marvell_nfc_op - filled during the parsing of the ->exec_op()
 *                         subop subset of instructions.
 *
 * @ndcb:               Array of values written to NDCBx registers
 * @cle_ale_delay_ns:   Optional delay after the last CMD or ADDR cycle
 * @rdy_timeout_ms:     Timeout for waits on Ready/Busy pin
 * @rdy_delay_ns:       Optional delay after waiting for the RB pin
 * @data_delay_ns:      Optional delay after the data xfer
 * @data_instr_idx:     Index of the data instruction in the subop
 * @data_instr:         Pointer to the data instruction in the subop
 */
struct marvell_nfc_op {
        u32 ndcb[4];
        unsigned int cle_ale_delay_ns;
        unsigned int rdy_timeout_ms;
        unsigned int rdy_delay_ns;
        unsigned int data_delay_ns;
        unsigned int data_instr_idx;
        const struct nand_op_instr *data_instr;
};

/*
 * Internal helper to conditionnally apply a delay (from the above structure,
 * most of the time).
 */
static void cond_delay(unsigned int ns)
{
        if (!ns)
                return;

        if (ns < 10000)
                ndelay(ns);
        else
                udelay(DIV_ROUND_UP(ns, 1000));
}

/*
 * The controller has many flags that could generate interrupts, most of them
 * are disabled and polling is used. For the very slow signals, using interrupts
 * may relax the CPU charge.
 */
static void marvell_nfc_disable_int(struct marvell_nfc *nfc, u32 int_mask)
{
        u32 reg;

        /* Writing 1 disables the interrupt */
        reg = readl_relaxed(nfc->regs + NDCR);
        writel_relaxed(reg | int_mask, nfc->regs + NDCR);
}

static void marvell_nfc_enable_int(struct marvell_nfc *nfc, u32 int_mask)
{
        u32 reg;

        /* Writing 0 enables the interrupt */
        reg = readl_relaxed(nfc->regs + NDCR);
        writel_relaxed(reg & ~int_mask, nfc->regs + NDCR);
}

static u32 marvell_nfc_clear_int(struct marvell_nfc *nfc, u32 int_mask)
{
        u32 reg;

        reg = readl_relaxed(nfc->regs + NDSR);
        writel_relaxed(int_mask, nfc->regs + NDSR);

        return reg & int_mask;
}

static void marvell_nfc_force_byte_access(struct nand_chip *chip,
                                          bool force_8bit)
{
        struct marvell_nfc *nfc = to_marvell_nfc(chip->controller);
        u32 ndcr;

        /*
         * Callers of this function do not verify if the NAND is using a 16-bit
         * an 8-bit bus for normal operations, so we need to take care of that
         * here by leaving the configuration unchanged if the NAND does not have
         * the NAND_BUSWIDTH_16 flag set.
         */
        if (!(chip->options & NAND_BUSWIDTH_16))
                return;

        ndcr = readl_relaxed(nfc->regs + NDCR);

        if (force_8bit)
                ndcr &= ~(NDCR_DWIDTH_M | NDCR_DWIDTH_C);
        else
                ndcr |= NDCR_DWIDTH_M | NDCR_DWIDTH_C;

        writel_relaxed(ndcr, nfc->regs + NDCR);
}

static int marvell_nfc_wait_ndrun(struct nand_chip *chip)
{
        struct marvell_nfc *nfc = to_marvell_nfc(chip->controller);
        u32 val;
        int ret;

        /*
         * The command is being processed, wait for the ND_RUN bit to be
         * cleared by the NFC. If not, we must clear it by hand.
         */
        ret = readl_relaxed_poll_timeout(nfc->regs + NDCR, val,
                                         (val & NDCR_ND_RUN) == 0,
                                         POLL_PERIOD, POLL_TIMEOUT);
        if (ret) {
                dev_err(nfc->dev, "Timeout on NAND controller run mode\n");
                writel_relaxed(readl(nfc->regs + NDCR) & ~NDCR_ND_RUN,
                               nfc->regs + NDCR);
                return ret;
        }

        return 0;
}

/*
 * Any time a command has to be sent to the controller, the following sequence
 * has to be followed:
 * - call marvell_nfc_prepare_cmd()
 *      -> activate the ND_RUN bit that will kind of 'start a job'
 *      -> wait the signal indicating the NFC is waiting for a command
 * - send the command (cmd and address cycles)
 * - enventually send or receive the data
 * - call marvell_nfc_end_cmd() with the corresponding flag
 *      -> wait the flag to be triggered or cancel the job with a timeout
 *
 * The following helpers are here to factorize the code a bit so that
 * specialized functions responsible for executing the actual NAND
 * operations do not have to replicate the same code blocks.
 */
static int marvell_nfc_prepare_cmd(struct nand_chip *chip)
{
        struct marvell_nfc *nfc = to_marvell_nfc(chip->controller);
        u32 ndcr, val;
        int ret;

        /* Poll ND_RUN and clear NDSR before issuing any command */
        ret = marvell_nfc_wait_ndrun(chip);
        if (ret) {
                dev_err(nfc->dev, "Last operation did not succeed\n");
                return ret;
        }

        ndcr = readl_relaxed(nfc->regs + NDCR);
        writel_relaxed(readl(nfc->regs + NDSR), nfc->regs + NDSR);

        /* Assert ND_RUN bit and wait the NFC to be ready */
        writel_relaxed(ndcr | NDCR_ND_RUN, nfc->regs + NDCR);
        ret = readl_relaxed_poll_timeout(nfc->regs + NDSR, val,
                                         val & NDSR_WRCMDREQ,
                                         POLL_PERIOD, POLL_TIMEOUT);
        if (ret) {
                dev_err(nfc->dev, "Timeout on WRCMDRE\n");
                return -ETIMEDOUT;
        }

        /* Command may be written, clear WRCMDREQ status bit */
        writel_relaxed(NDSR_WRCMDREQ, nfc->regs + NDSR);

        return 0;
}

static void marvell_nfc_send_cmd(struct nand_chip *chip,
                                 struct marvell_nfc_op *nfc_op)
{
        struct marvell_nand_chip *marvell_nand = to_marvell_nand(chip);
        struct marvell_nfc *nfc = to_marvell_nfc(chip->controller);

        dev_dbg(nfc->dev, "\nNDCR:  0x%08x\n"
                "NDCB0: 0x%08x\nNDCB1: 0x%08x\nNDCB2: 0x%08x\nNDCB3: 0x%08x\n",
                (u32)readl_relaxed(nfc->regs + NDCR), nfc_op->ndcb[0],
                nfc_op->ndcb[1], nfc_op->ndcb[2], nfc_op->ndcb[3]);

        writel_relaxed(to_nand_sel(marvell_nand)->ndcb0_csel | nfc_op->ndcb[0],
                       nfc->regs + NDCB0);
        writel_relaxed(nfc_op->ndcb[1], nfc->regs + NDCB0);
        writel(nfc_op->ndcb[2], nfc->regs + NDCB0);

        /*
         * Write NDCB0 four times only if LEN_OVRD is set or if ADDR6 or ADDR7
         * fields are used (only available on NFCv2).
         */
        if (nfc_op->ndcb[0] & NDCB0_LEN_OVRD ||
            NDCB0_ADDR_GET_NUM_CYC(nfc_op->ndcb[0]) >= 6) {
                if (!WARN_ON_ONCE(!nfc->caps->is_nfcv2))
                        writel(nfc_op->ndcb[3], nfc->regs + NDCB0);
        }
}

static int marvell_nfc_end_cmd(struct nand_chip *chip, int flag,
                               const char *label)
{
        struct marvell_nfc *nfc = to_marvell_nfc(chip->controller);
        u32 val;
        int ret;

        ret = readl_relaxed_poll_timeout(nfc->regs + NDSR, val,
                                         val & flag,
                                         POLL_PERIOD, POLL_TIMEOUT);

        if (ret) {
                dev_err(nfc->dev, "Timeout on %s (NDSR: 0x%08x)\n",
                        label, val);
                if (nfc->dma_chan)
                        dmaengine_terminate_all(nfc->dma_chan);
                return ret;
        }

        /*
         * DMA function uses this helper to poll on CMDD bits without wanting
         * them to be cleared.
         */
        if (nfc->use_dma && (readl_relaxed(nfc->regs + NDCR) & NDCR_DMA_EN))
                return 0;

        writel_relaxed(flag, nfc->regs + NDSR);

        return 0;
}

static int marvell_nfc_wait_cmdd(struct nand_chip *chip)
{
        struct marvell_nand_chip *marvell_nand = to_marvell_nand(chip);
        int cs_flag = NDSR_CMDD(to_nand_sel(marvell_nand)->ndcb0_csel);

        return marvell_nfc_end_cmd(chip, cs_flag, "CMDD");
}

static int marvell_nfc_poll_status(struct marvell_nfc *nfc, u32 mask,
                                   u32 expected_val, unsigned long timeout_ms)
{
        unsigned long limit;
        u32 st;

        limit = jiffies + msecs_to_jiffies(timeout_ms);
        do {
                st = readl_relaxed(nfc->regs + NDSR);
                if (st & NDSR_RDY(1))
                        st |= NDSR_RDY(0);

                if ((st & mask) == expected_val)
                        return 0;

                cpu_relax();
        } while (time_after(limit, jiffies));

        return -ETIMEDOUT;
}

static int marvell_nfc_wait_op(struct nand_chip *chip, unsigned int timeout_ms)
{
        struct marvell_nfc *nfc = to_marvell_nfc(chip->controller);
        struct mtd_info *mtd = nand_to_mtd(chip);
        u32 pending;
        int ret;

        /* Timeout is expressed in ms */
        if (!timeout_ms)
                timeout_ms = IRQ_TIMEOUT;

        if (mtd->oops_panic_write) {
                ret = marvell_nfc_poll_status(nfc, NDSR_RDY(0),
                                              NDSR_RDY(0),
                                              timeout_ms);
        } else {
                init_completion(&nfc->complete);

                marvell_nfc_enable_int(nfc, NDCR_RDYM);
                ret = wait_for_completion_timeout(&nfc->complete,
                                                  msecs_to_jiffies(timeout_ms));
                marvell_nfc_disable_int(nfc, NDCR_RDYM);
        }
        pending = marvell_nfc_clear_int(nfc, NDSR_RDY(0) | NDSR_RDY(1));

        /*
         * In case the interrupt was not served in the required time frame,
         * check if the ISR was not served or if something went actually wrong.
         */
        if (!ret && !pending) {
                dev_err(nfc->dev, "Timeout waiting for RB signal\n");
                return -ETIMEDOUT;
        }

        return 0;
}

static void marvell_nfc_select_target(struct nand_chip *chip,
                                      unsigned int die_nr)
{
        struct marvell_nand_chip *marvell_nand = to_marvell_nand(chip);
        struct marvell_nfc *nfc = to_marvell_nfc(chip->controller);
        u32 ndcr_generic;

        /*
         * Reset the NDCR register to a clean state for this particular chip,
         * also clear ND_RUN bit.
         */
        ndcr_generic = readl_relaxed(nfc->regs + NDCR) &
                       NDCR_GENERIC_FIELDS_MASK & ~NDCR_ND_RUN;
        writel_relaxed(ndcr_generic | marvell_nand->ndcr, nfc->regs + NDCR);

        /* Also reset the interrupt status register */
        marvell_nfc_clear_int(nfc, NDCR_ALL_INT);

        if (chip == nfc->selected_chip && die_nr == marvell_nand->selected_die)
                return;

        writel_relaxed(marvell_nand->ndtr0, nfc->regs + NDTR0);
        writel_relaxed(marvell_nand->ndtr1, nfc->regs + NDTR1);

        nfc->selected_chip = chip;
        marvell_nand->selected_die = die_nr;
}

static irqreturn_t marvell_nfc_isr(int irq, void *dev_id)
{
        struct marvell_nfc *nfc = dev_id;
        u32 st = readl_relaxed(nfc->regs + NDSR);
        u32 ien = (~readl_relaxed(nfc->regs + NDCR)) & NDCR_ALL_INT;

        /*
         * RDY interrupt mask is one bit in NDCR while there are two status
         * bit in NDSR (RDY[cs0/cs2] and RDY[cs1/cs3]).
         */
        if (st & NDSR_RDY(1))
                st |= NDSR_RDY(0);

        if (!(st & ien))
                return IRQ_NONE;

        marvell_nfc_disable_int(nfc, st & NDCR_ALL_INT);

        if (st & (NDSR_RDY(0) | NDSR_RDY(1)))
                complete(&nfc->complete);

        return IRQ_HANDLED;
}

/* HW ECC related functions */
static void marvell_nfc_enable_hw_ecc(struct nand_chip *chip)
{
        struct marvell_nfc *nfc = to_marvell_nfc(chip->controller);
        u32 ndcr = readl_relaxed(nfc->regs + NDCR);

        if (!(ndcr & NDCR_ECC_EN)) {
                writel_relaxed(ndcr | NDCR_ECC_EN, nfc->regs + NDCR);

                /*
                 * When enabling BCH, set threshold to 0 to always know the
                 * number of corrected bitflips.
                 */
                if (chip->ecc.algo == NAND_ECC_ALGO_BCH)
                        writel_relaxed(NDECCCTRL_BCH_EN, nfc->regs + NDECCCTRL);
        }
}

static void marvell_nfc_disable_hw_ecc(struct nand_chip *chip)
{
        struct marvell_nfc *nfc = to_marvell_nfc(chip->controller);
        u32 ndcr = readl_relaxed(nfc->regs + NDCR);

        if (ndcr & NDCR_ECC_EN) {
                writel_relaxed(ndcr & ~NDCR_ECC_EN, nfc->regs + NDCR);
                if (chip->ecc.algo == NAND_ECC_ALGO_BCH)
                        writel_relaxed(0, nfc->regs + NDECCCTRL);
        }
}

/* DMA related helpers */
static void marvell_nfc_enable_dma(struct marvell_nfc *nfc)
{
        u32 reg;

        reg = readl_relaxed(nfc->regs + NDCR);
        writel_relaxed(reg | NDCR_DMA_EN, nfc->regs + NDCR);
}

static void marvell_nfc_disable_dma(struct marvell_nfc *nfc)
{
        u32 reg;

        reg = readl_relaxed(nfc->regs + NDCR);
        writel_relaxed(reg & ~NDCR_DMA_EN, nfc->regs + NDCR);
}

/* Read/write PIO/DMA accessors */
static int marvell_nfc_xfer_data_dma(struct marvell_nfc *nfc,
                                     enum dma_data_direction direction,
                                     unsigned int len)
{
        unsigned int dma_len = min_t(int, ALIGN(len, 32), MAX_CHUNK_SIZE);
        struct dma_async_tx_descriptor *tx;
        struct scatterlist sg;
        dma_cookie_t cookie;
        int ret;

        marvell_nfc_enable_dma(nfc);
        /* Prepare the DMA transfer */
        sg_init_one(&sg, nfc->dma_buf, dma_len);
        dma_map_sg(nfc->dma_chan->device->dev, &sg, 1, direction);
        tx = dmaengine_prep_slave_sg(nfc->dma_chan, &sg, 1,
                                     direction == DMA_FROM_DEVICE ?
                                     DMA_DEV_TO_MEM : DMA_MEM_TO_DEV,
                                     DMA_PREP_INTERRUPT);
        if (!tx) {
                dev_err(nfc->dev, "Could not prepare DMA S/G list\n");
                return -ENXIO;
        }

        /* Do the task and wait for it to finish */
        cookie = dmaengine_submit(tx);
        ret = dma_submit_error(cookie);
        if (ret)
                return -EIO;

        dma_async_issue_pending(nfc->dma_chan);
        ret = marvell_nfc_wait_cmdd(nfc->selected_chip);
        dma_unmap_sg(nfc->dma_chan->device->dev, &sg, 1, direction);
        marvell_nfc_disable_dma(nfc);
        if (ret) {
                dev_err(nfc->dev, "Timeout waiting for DMA (status: %d)\n",
                        dmaengine_tx_status(nfc->dma_chan, cookie, NULL));
                dmaengine_terminate_all(nfc->dma_chan);
                return -ETIMEDOUT;
        }

        return 0;
}

static int marvell_nfc_xfer_data_in_pio(struct marvell_nfc *nfc, u8 *in,
                                        unsigned int len)
{
        unsigned int last_len = len % FIFO_DEPTH;
        unsigned int last_full_offset = round_down(len, FIFO_DEPTH);
        int i;

        for (i = 0; i < last_full_offset; i += FIFO_DEPTH)
                ioread32_rep(nfc->regs + NDDB, in + i, FIFO_REP(FIFO_DEPTH));

        if (last_len) {
                u8 tmp_buf[FIFO_DEPTH];

                ioread32_rep(nfc->regs + NDDB, tmp_buf, FIFO_REP(FIFO_DEPTH));
                memcpy(in + last_full_offset, tmp_buf, last_len);
        }

        return 0;
}

static int marvell_nfc_xfer_data_out_pio(struct marvell_nfc *nfc, const u8 *out,
                                         unsigned int len)
{
        unsigned int last_len = len % FIFO_DEPTH;
        unsigned int last_full_offset = round_down(len, FIFO_DEPTH);
        int i;

        for (i = 0; i < last_full_offset; i += FIFO_DEPTH)
                iowrite32_rep(nfc->regs + NDDB, out + i, FIFO_REP(FIFO_DEPTH));

        if (last_len) {
                u8 tmp_buf[FIFO_DEPTH];

                memcpy(tmp_buf, out + last_full_offset, last_len);
                iowrite32_rep(nfc->regs + NDDB, tmp_buf, FIFO_REP(FIFO_DEPTH));
        }

        return 0;
}

static void marvell_nfc_check_empty_chunk(struct nand_chip *chip,
                                          u8 *data, int data_len,
                                          u8 *spare, int spare_len,
                                          u8 *ecc, int ecc_len,
                                          unsigned int *max_bitflips)
{
        struct mtd_info *mtd = nand_to_mtd(chip);
        int bf;

        /*
         * Blank pages (all 0xFF) that have not been written may be recognized
         * as bad if bitflips occur, so whenever an uncorrectable error occurs,
         * check if the entire page (with ECC bytes) is actually blank or not.
         */
        if (!data)
                data_len = 0;
        if (!spare)
                spare_len = 0;
        if (!ecc)
                ecc_len = 0;

        bf = nand_check_erased_ecc_chunk(data, data_len, ecc, ecc_len,
                                         spare, spare_len, chip->ecc.strength);
        if (bf < 0) {
                mtd->ecc_stats.failed++;
                return;
        }

        /* Update the stats and max_bitflips */
        mtd->ecc_stats.corrected += bf;
        *max_bitflips = max_t(unsigned int, *max_bitflips, bf);
}

/*
 * Check if a chunk is correct or not according to the hardware ECC engine.
 * mtd->ecc_stats.corrected is updated, as well as max_bitflips, however
 * mtd->ecc_stats.failure is not, the function will instead return a non-zero
 * value indicating that a check on the emptyness of the subpage must be
 * performed before actually declaring the subpage as "corrupted".
 */
static int marvell_nfc_hw_ecc_check_bitflips(struct nand_chip *chip,
                                             unsigned int *max_bitflips)
{
        struct mtd_info *mtd = nand_to_mtd(chip);
        struct marvell_nfc *nfc = to_marvell_nfc(chip->controller);
        int bf = 0;
        u32 ndsr;

        ndsr = readl_relaxed(nfc->regs + NDSR);

        /* Check uncorrectable error flag */
        if (ndsr & NDSR_UNCERR) {
                writel_relaxed(ndsr, nfc->regs + NDSR);

                /*
                 * Do not increment ->ecc_stats.failed now, instead, return a
                 * non-zero value to indicate that this chunk was apparently
                 * bad, and it should be check to see if it empty or not. If
                 * the chunk (with ECC bytes) is not declared empty, the calling
                 * function must increment the failure count.
                 */
                return -EBADMSG;
        }

        /* Check correctable error flag */
        if (ndsr & NDSR_CORERR) {
                writel_relaxed(ndsr, nfc->regs + NDSR);

                if (chip->ecc.algo == NAND_ECC_ALGO_BCH)
                        bf = NDSR_ERRCNT(ndsr);
                else
                        bf = 1;
        }

        /* Update the stats and max_bitflips */
        mtd->ecc_stats.corrected += bf;
        *max_bitflips = max_t(unsigned int, *max_bitflips, bf);

        return 0;
}

/* Hamming read helpers */
static int marvell_nfc_hw_ecc_hmg_do_read_page(struct nand_chip *chip,
                                               u8 *data_buf, u8 *oob_buf,
                                               bool raw, int page)
{
        struct marvell_nand_chip *marvell_nand = to_marvell_nand(chip);
        struct marvell_nfc *nfc = to_marvell_nfc(chip->controller);
        const struct marvell_hw_ecc_layout *lt = to_marvell_nand(chip)->layout;
        struct marvell_nfc_op nfc_op = {
                .ndcb[0] = NDCB0_CMD_TYPE(TYPE_READ) |
                           NDCB0_ADDR_CYC(marvell_nand->addr_cyc) |
                           NDCB0_DBC |
                           NDCB0_CMD1(NAND_CMD_READ0) |
                           NDCB0_CMD2(NAND_CMD_READSTART),
                .ndcb[1] = NDCB1_ADDRS_PAGE(page),
                .ndcb[2] = NDCB2_ADDR5_PAGE(page),
        };
        unsigned int oob_bytes = lt->spare_bytes + (raw ? lt->ecc_bytes : 0);
        int ret;

        /* NFCv2 needs more information about the operation being executed */
        if (nfc->caps->is_nfcv2)
                nfc_op.ndcb[0] |= NDCB0_CMD_XTYPE(XTYPE_MONOLITHIC_RW);

        ret = marvell_nfc_prepare_cmd(chip);
        if (ret)
                return ret;

        marvell_nfc_send_cmd(chip, &nfc_op);
        ret = marvell_nfc_end_cmd(chip, NDSR_RDDREQ,
                                  "RDDREQ while draining FIFO (data/oob)");
        if (ret)
                return ret;

        /*
         * Read the page then the OOB area. Unlike what is shown in current
         * documentation, spare bytes are protected by the ECC engine, and must
         * be at the beginning of the OOB area or running this driver on legacy
         * systems will prevent the discovery of the BBM/BBT.
         */
        if (nfc->use_dma) {
                marvell_nfc_xfer_data_dma(nfc, DMA_FROM_DEVICE,
                                          lt->data_bytes + oob_bytes);
                memcpy(data_buf, nfc->dma_buf, lt->data_bytes);
                memcpy(oob_buf, nfc->dma_buf + lt->data_bytes, oob_bytes);
        } else {
                marvell_nfc_xfer_data_in_pio(nfc, data_buf, lt->data_bytes);
                marvell_nfc_xfer_data_in_pio(nfc, oob_buf, oob_bytes);
        }

        ret = marvell_nfc_wait_cmdd(chip);
        return ret;
}

static int marvell_nfc_hw_ecc_hmg_read_page_raw(struct nand_chip *chip, u8 *buf,
                                                int oob_required, int page)
{
        marvell_nfc_select_target(chip, chip->cur_cs);
        return marvell_nfc_hw_ecc_hmg_do_read_page(chip, buf, chip->oob_poi,
                                                   true, page);
}

static int marvell_nfc_hw_ecc_hmg_read_page(struct nand_chip *chip, u8 *buf,
                                            int oob_required, int page)
{
        const struct marvell_hw_ecc_layout *lt = to_marvell_nand(chip)->layout;
        unsigned int full_sz = lt->data_bytes + lt->spare_bytes + lt->ecc_bytes;
        int max_bitflips = 0, ret;
        u8 *raw_buf;

        marvell_nfc_select_target(chip, chip->cur_cs);
        marvell_nfc_enable_hw_ecc(chip);
        marvell_nfc_hw_ecc_hmg_do_read_page(chip, buf, chip->oob_poi, false,
                                            page);
        ret = marvell_nfc_hw_ecc_check_bitflips(chip, &max_bitflips);
        marvell_nfc_disable_hw_ecc(chip);

        if (!ret)
                return max_bitflips;

        /*
         * When ECC failures are detected, check if the full page has been
         * written or not. Ignore the failure if it is actually empty.
         */
        raw_buf = kmalloc(full_sz, GFP_KERNEL);
        if (!raw_buf)
                return -ENOMEM;

        marvell_nfc_hw_ecc_hmg_do_read_page(chip, raw_buf, raw_buf +
                                            lt->data_bytes, true, page);
        marvell_nfc_check_empty_chunk(chip, raw_buf, full_sz, NULL, 0, NULL, 0,
                                      &max_bitflips);
        kfree(raw_buf);

        return max_bitflips;
}

/*
 * Spare area in Hamming layouts is not protected by the ECC engine (even if
 * it appears before the ECC bytes when reading), the ->read_oob_raw() function
 * also stands for ->read_oob().
 */
static int marvell_nfc_hw_ecc_hmg_read_oob_raw(struct nand_chip *chip, int page)
{
        u8 *buf = nand_get_data_buf(chip);

        marvell_nfc_select_target(chip, chip->cur_cs);
        return marvell_nfc_hw_ecc_hmg_do_read_page(chip, buf, chip->oob_poi,
                                                   true, page);
}

/* Hamming write helpers */
static int marvell_nfc_hw_ecc_hmg_do_write_page(struct nand_chip *chip,
                                                const u8 *data_buf,
                                                const u8 *oob_buf, bool raw,
                                                int page)
{
        const struct nand_sdr_timings *sdr =
                nand_get_sdr_timings(nand_get_interface_config(chip));
        struct marvell_nand_chip *marvell_nand = to_marvell_nand(chip);
        struct marvell_nfc *nfc = to_marvell_nfc(chip->controller);
        const struct marvell_hw_ecc_layout *lt = to_marvell_nand(chip)->layout;
        struct marvell_nfc_op nfc_op = {
                .ndcb[0] = NDCB0_CMD_TYPE(TYPE_WRITE) |
                           NDCB0_ADDR_CYC(marvell_nand->addr_cyc) |
                           NDCB0_CMD1(NAND_CMD_SEQIN) |
                           NDCB0_CMD2(NAND_CMD_PAGEPROG) |
                           NDCB0_DBC,
                .ndcb[1] = NDCB1_ADDRS_PAGE(page),
                .ndcb[2] = NDCB2_ADDR5_PAGE(page),
        };
        unsigned int oob_bytes = lt->spare_bytes + (raw ? lt->ecc_bytes : 0);
        int ret;

        /* NFCv2 needs more information about the operation being executed */
        if (nfc->caps->is_nfcv2)
                nfc_op.ndcb[0] |= NDCB0_CMD_XTYPE(XTYPE_MONOLITHIC_RW);

        ret = marvell_nfc_prepare_cmd(chip);
        if (ret)
                return ret;

        marvell_nfc_send_cmd(chip, &nfc_op);
        ret = marvell_nfc_end_cmd(chip, NDSR_WRDREQ,
                                  "WRDREQ while loading FIFO (data)");
        if (ret)
                return ret;

        /* Write the page then the OOB area */
        if (nfc->use_dma) {
                memcpy(nfc->dma_buf, data_buf, lt->data_bytes);
                memcpy(nfc->dma_buf + lt->data_bytes, oob_buf, oob_bytes);
                marvell_nfc_xfer_data_dma(nfc, DMA_TO_DEVICE, lt->data_bytes +
                                          lt->ecc_bytes + lt->spare_bytes);
        } else {
                marvell_nfc_xfer_data_out_pio(nfc, data_buf, lt->data_bytes);
                marvell_nfc_xfer_data_out_pio(nfc, oob_buf, oob_bytes);
        }

        ret = marvell_nfc_wait_cmdd(chip);
        if (ret)
                return ret;

        ret = marvell_nfc_wait_op(chip,
                                  PSEC_TO_MSEC(sdr->tPROG_max));
        return ret;
}

static int marvell_nfc_hw_ecc_hmg_write_page_raw(struct nand_chip *chip,
                                                 const u8 *buf,
                                                 int oob_required, int page)
{
        marvell_nfc_select_target(chip, chip->cur_cs);
        return marvell_nfc_hw_ecc_hmg_do_write_page(chip, buf, chip->oob_poi,
                                                    true, page);
}

static int marvell_nfc_hw_ecc_hmg_write_page(struct nand_chip *chip,
                                             const u8 *buf,
                                             int oob_required, int page)
{
        int ret;

        marvell_nfc_select_target(chip, chip->cur_cs);
        marvell_nfc_enable_hw_ecc(chip);
        ret = marvell_nfc_hw_ecc_hmg_do_write_page(chip, buf, chip->oob_poi,
                                                   false, page);
        marvell_nfc_disable_hw_ecc(chip);

        return ret;
}

/*
 * Spare area in Hamming layouts is not protected by the ECC engine (even if
 * it appears before the ECC bytes when reading), the ->write_oob_raw() function
 * also stands for ->write_oob().
 */
static int marvell_nfc_hw_ecc_hmg_write_oob_raw(struct nand_chip *chip,
                                                int page)
{
        struct mtd_info *mtd = nand_to_mtd(chip);
        u8 *buf = nand_get_data_buf(chip);

        memset(buf, 0xFF, mtd->writesize);

        marvell_nfc_select_target(chip, chip->cur_cs);
        return marvell_nfc_hw_ecc_hmg_do_write_page(chip, buf, chip->oob_poi,
                                                    true, page);
}

/* BCH read helpers */
static int marvell_nfc_hw_ecc_bch_read_page_raw(struct nand_chip *chip, u8 *buf,
                                                int oob_required, int page)
{
        struct mtd_info *mtd = nand_to_mtd(chip);
        const struct marvell_hw_ecc_layout *lt = to_marvell_nand(chip)->layout;
        u8 *oob = chip->oob_poi;
        int chunk_size = lt->data_bytes + lt->spare_bytes + lt->ecc_bytes;
        int ecc_offset = (lt->full_chunk_cnt * lt->spare_bytes) +
                lt->last_spare_bytes;
        int data_len = lt->data_bytes;
        int spare_len = lt->spare_bytes;
        int ecc_len = lt->ecc_bytes;
        int chunk;

        marvell_nfc_select_target(chip, chip->cur_cs);

        if (oob_required)
                memset(chip->oob_poi, 0xFF, mtd->oobsize);

        nand_read_page_op(chip, page, 0, NULL, 0);

        for (chunk = 0; chunk < lt->nchunks; chunk++) {
                /* Update last chunk length */
                if (chunk >= lt->full_chunk_cnt) {
                        data_len = lt->last_data_bytes;
                        spare_len = lt->last_spare_bytes;
                        ecc_len = lt->last_ecc_bytes;
                }

                /* Read data bytes*/
                nand_change_read_column_op(chip, chunk * chunk_size,
                                           buf + (lt->data_bytes * chunk),
                                           data_len, false);

                /* Read spare bytes */
                nand_read_data_op(chip, oob + (lt->spare_bytes * chunk),
                                  spare_len, false, false);

                /* Read ECC bytes */
                nand_read_data_op(chip, oob + ecc_offset +
                                  (ALIGN(lt->ecc_bytes, 32) * chunk),
                                  ecc_len, false, false);
        }

        return 0;
}

static void marvell_nfc_hw_ecc_bch_read_chunk(struct nand_chip *chip, int chunk,
                                              u8 *data, unsigned int data_len,
                                              u8 *spare, unsigned int spare_len,
                                              int page)
{
        struct marvell_nand_chip *marvell_nand = to_marvell_nand(chip);
        struct marvell_nfc *nfc = to_marvell_nfc(chip->controller);
        const struct marvell_hw_ecc_layout *lt = to_marvell_nand(chip)->layout;
        int i, ret;
        struct marvell_nfc_op nfc_op = {
                .ndcb[0] = NDCB0_CMD_TYPE(TYPE_READ) |
                           NDCB0_ADDR_CYC(marvell_nand->addr_cyc) |
                           NDCB0_LEN_OVRD,
                .ndcb[1] = NDCB1_ADDRS_PAGE(page),
                .ndcb[2] = NDCB2_ADDR5_PAGE(page),
                .ndcb[3] = data_len + spare_len,
        };

        ret = marvell_nfc_prepare_cmd(chip);
        if (ret)
                return;

        if (chunk == 0)
                nfc_op.ndcb[0] |= NDCB0_DBC |
                                  NDCB0_CMD1(NAND_CMD_READ0) |
                                  NDCB0_CMD2(NAND_CMD_READSTART);

        /*
         * Trigger the monolithic read on the first chunk, then naked read on
         * intermediate chunks and finally a last naked read on the last chunk.
         */
        if (chunk == 0)
                nfc_op.ndcb[0] |= NDCB0_CMD_XTYPE(XTYPE_MONOLITHIC_RW);
        else if (chunk < lt->nchunks - 1)
                nfc_op.ndcb[0] |= NDCB0_CMD_XTYPE(XTYPE_NAKED_RW);
        else
                nfc_op.ndcb[0] |= NDCB0_CMD_XTYPE(XTYPE_LAST_NAKED_RW);

        marvell_nfc_send_cmd(chip, &nfc_op);

        /*
         * According to the datasheet, when reading from NDDB
         * with BCH enabled, after each 32 bytes reads, we
         * have to make sure that the NDSR.RDDREQ bit is set.
         *
         * Drain the FIFO, 8 32-bit reads at a time, and skip
         * the polling on the last read.
         *
         * Length is a multiple of 32 bytes, hence it is a multiple of 8 too.
         */
        for (i = 0; i < data_len; i += FIFO_DEPTH * BCH_SEQ_READS) {
                marvell_nfc_end_cmd(chip, NDSR_RDDREQ,
                                    "RDDREQ while draining FIFO (data)");
                marvell_nfc_xfer_data_in_pio(nfc, data,
                                             FIFO_DEPTH * BCH_SEQ_READS);
                data += FIFO_DEPTH * BCH_SEQ_READS;
        }

        for (i = 0; i < spare_len; i += FIFO_DEPTH * BCH_SEQ_READS) {
                marvell_nfc_end_cmd(chip, NDSR_RDDREQ,
                                    "RDDREQ while draining FIFO (OOB)");
                marvell_nfc_xfer_data_in_pio(nfc, spare,
                                             FIFO_DEPTH * BCH_SEQ_READS);
                spare += FIFO_DEPTH * BCH_SEQ_READS;
        }
}

static int marvell_nfc_hw_ecc_bch_read_page(struct nand_chip *chip,
                                            u8 *buf, int oob_required,
                                            int page)
{
        struct mtd_info *mtd = nand_to_mtd(chip);
        const struct marvell_hw_ecc_layout *lt = to_marvell_nand(chip)->layout;
        int data_len = lt->data_bytes, spare_len = lt->spare_bytes;
        u8 *data = buf, *spare = chip->oob_poi;
        int max_bitflips = 0;
        u32 failure_mask = 0;
        int chunk, ret;

        marvell_nfc_select_target(chip, chip->cur_cs);

        /*
         * With BCH, OOB is not fully used (and thus not read entirely), not
         * expected bytes could show up at the end of the OOB buffer if not
         * explicitly erased.
         */
        if (oob_required)
                memset(chip->oob_poi, 0xFF, mtd->oobsize);

        marvell_nfc_enable_hw_ecc(chip);

        for (chunk = 0; chunk < lt->nchunks; chunk++) {
                /* Update length for the last chunk */
                if (chunk >= lt->full_chunk_cnt) {
                        data_len = lt->last_data_bytes;
                        spare_len = lt->last_spare_bytes;
                }

                /* Read the chunk and detect number of bitflips */
                marvell_nfc_hw_ecc_bch_read_chunk(chip, chunk, data, data_len,
                                                  spare, spare_len, page);
                ret = marvell_nfc_hw_ecc_check_bitflips(chip, &max_bitflips);
                if (ret)
                        failure_mask |= BIT(chunk);

                data += data_len;
                spare += spare_len;
        }

        marvell_nfc_disable_hw_ecc(chip);

        if (!failure_mask)
                return max_bitflips;

        /*
         * Please note that dumping the ECC bytes during a normal read with OOB
         * area would add a significant overhead as ECC bytes are "consumed" by
         * the controller in normal mode and must be re-read in raw mode. To
         * avoid dropping the performances, we prefer not to include them. The
         * user should re-read the page in raw mode if ECC bytes are required.
         */

        /*
         * In case there is any subpage read error, we usually re-read only ECC
         * bytes in raw mode and check if the whole page is empty. In this case,
         * it is normal that the ECC check failed and we just ignore the error.
         *
         * However, it has been empirically observed that for some layouts (e.g
         * 2k page, 8b strength per 512B chunk), the controller tries to correct
         * bits and may create itself bitflips in the erased area. To overcome
         * this strange behavior, the whole page is re-read in raw mode, not
         * only the ECC bytes.
         */
        for (chunk = 0; chunk < lt->nchunks; chunk++) {
                int data_off_in_page, spare_off_in_page, ecc_off_in_page;
                int data_off, spare_off, ecc_off;
                int data_len, spare_len, ecc_len;

                /* No failure reported for this chunk, move to the next one */
                if (!(failure_mask & BIT(chunk)))
                        continue;

                data_off_in_page = chunk * (lt->data_bytes + lt->spare_bytes +
                                            lt->ecc_bytes);
                spare_off_in_page = data_off_in_page +
                        (chunk < lt->full_chunk_cnt ? lt->data_bytes :
                                                      lt->last_data_bytes);
                ecc_off_in_page = spare_off_in_page +
                        (chunk < lt->full_chunk_cnt ? lt->spare_bytes :
                                                      lt->last_spare_bytes);

                data_off = chunk * lt->data_bytes;
                spare_off = chunk * lt->spare_bytes;
                ecc_off = (lt->full_chunk_cnt * lt->spare_bytes) +
                          lt->last_spare_bytes +
                          (chunk * (lt->ecc_bytes + 2));

                data_len = chunk < lt->full_chunk_cnt ? lt->data_bytes :
                                                        lt->last_data_bytes;
                spare_len = chunk < lt->full_chunk_cnt ? lt->spare_bytes :
                                                         lt->last_spare_bytes;
                ecc_len = chunk < lt->full_chunk_cnt ? lt->ecc_bytes :
                                                       lt->last_ecc_bytes;

                /*
                 * Only re-read the ECC bytes, unless we are using the 2k/8b
                 * layout which is buggy in the sense that the ECC engine will
                 * try to correct data bytes anyway, creating bitflips. In this
                 * case, re-read the entire page.
                 */
                if (lt->writesize == 2048 && lt->strength == 8) {
                        nand_change_read_column_op(chip, data_off_in_page,
                                                   buf + data_off, data_len,
                                                   false);
                        nand_change_read_column_op(chip, spare_off_in_page,
                                                   chip->oob_poi + spare_off, spare_len,
                                                   false);
                }

                nand_change_read_column_op(chip, ecc_off_in_page,
                                           chip->oob_poi + ecc_off, ecc_len,
                                           false);

                /* Check the entire chunk (data + spare + ecc) for emptyness */
                marvell_nfc_check_empty_chunk(chip, buf + data_off, data_len,
                                              chip->oob_poi + spare_off, spare_len,
                                              chip->oob_poi + ecc_off, ecc_len,
                                              &max_bitflips);
        }

        return max_bitflips;
}

static int marvell_nfc_hw_ecc_bch_read_oob_raw(struct nand_chip *chip, int page)
{
        u8 *buf = nand_get_data_buf(chip);

        return chip->ecc.read_page_raw(chip, buf, true, page);
}

static int marvell_nfc_hw_ecc_bch_read_oob(struct nand_chip *chip, int page)
{
        u8 *buf = nand_get_data_buf(chip);

        return chip->ecc.read_page(chip, buf, true, page);
}

/* BCH write helpers */
static int marvell_nfc_hw_ecc_bch_write_page_raw(struct nand_chip *chip,
                                                 const u8 *buf,
                                                 int oob_required, int page)
{
        const struct marvell_hw_ecc_layout *lt = to_marvell_nand(chip)->layout;
        int full_chunk_size = lt->data_bytes + lt->spare_bytes + lt->ecc_bytes;
        int data_len = lt->data_bytes;
        int spare_len = lt->spare_bytes;
        int ecc_len = lt->ecc_bytes;
        int spare_offset = 0;
        int ecc_offset = (lt->full_chunk_cnt * lt->spare_bytes) +
                lt->last_spare_bytes;
        int chunk;

        marvell_nfc_select_target(chip, chip->cur_cs);

        nand_prog_page_begin_op(chip, page, 0, NULL, 0);

        for (chunk = 0; chunk < lt->nchunks; chunk++) {
                if (chunk >= lt->full_chunk_cnt) {
                        data_len = lt->last_data_bytes;
                        spare_len = lt->last_spare_bytes;
                        ecc_len = lt->last_ecc_bytes;
                }

                /* Point to the column of the next chunk */
                nand_change_write_column_op(chip, chunk * full_chunk_size,
                                            NULL, 0, false);

                /* Write the data */
                nand_write_data_op(chip, buf + (chunk * lt->data_bytes),
                                   data_len, false);

                if (!oob_required)
                        continue;

                /* Write the spare bytes */
                if (spare_len)
                        nand_write_data_op(chip, chip->oob_poi + spare_offset,
                                           spare_len, false);

                /* Write the ECC bytes */
                if (ecc_len)
                        nand_write_data_op(chip, chip->oob_poi + ecc_offset,
                                           ecc_len, false);

                spare_offset += spare_len;
                ecc_offset += ALIGN(ecc_len, 32);
        }

        return nand_prog_page_end_op(chip);
}

static int
marvell_nfc_hw_ecc_bch_write_chunk(struct nand_chip *chip, int chunk,
                                   const u8 *data, unsigned int data_len,
                                   const u8 *spare, unsigned int spare_len,
                                   int page)
{
        struct marvell_nand_chip *marvell_nand = to_marvell_nand(chip);
        struct marvell_nfc *nfc = to_marvell_nfc(chip->controller);
        const struct marvell_hw_ecc_layout *lt = to_marvell_nand(chip)->layout;
        u32 xtype;
        int ret;
        struct marvell_nfc_op nfc_op = {
                .ndcb[0] = NDCB0_CMD_TYPE(TYPE_WRITE) | NDCB0_LEN_OVRD,
                .ndcb[3] = data_len + spare_len,
        };

        /*
         * First operation dispatches the CMD_SEQIN command, issue the address
         * cycles and asks for the first chunk of data.
         * All operations in the middle (if any) will issue a naked write and
         * also ask for data.
         * Last operation (if any) asks for the last chunk of data through a
         * last naked write.
         */
        if (chunk == 0) {
                if (lt->nchunks == 1)
                        xtype = XTYPE_MONOLITHIC_RW;
                else
                        xtype = XTYPE_WRITE_DISPATCH;

                nfc_op.ndcb[0] |= NDCB0_CMD_XTYPE(xtype) |
                                  NDCB0_ADDR_CYC(marvell_nand->addr_cyc) |
                                  NDCB0_CMD1(NAND_CMD_SEQIN);
                nfc_op.ndcb[1] |= NDCB1_ADDRS_PAGE(page);
                nfc_op.ndcb[2] |= NDCB2_ADDR5_PAGE(page);
        } else if (chunk < lt->nchunks - 1) {
                nfc_op.ndcb[0] |= NDCB0_CMD_XTYPE(XTYPE_NAKED_RW);
        } else {
                nfc_op.ndcb[0] |= NDCB0_CMD_XTYPE(XTYPE_LAST_NAKED_RW);
        }

        /* Always dispatch the PAGEPROG command on the last chunk */
        if (chunk == lt->nchunks - 1)
                nfc_op.ndcb[0] |= NDCB0_CMD2(NAND_CMD_PAGEPROG) | NDCB0_DBC;

        ret = marvell_nfc_prepare_cmd(chip);
        if (ret)
                return ret;

        marvell_nfc_send_cmd(chip, &nfc_op);
        ret = marvell_nfc_end_cmd(chip, NDSR_WRDREQ,
                                  "WRDREQ while loading FIFO (data)");
        if (ret)
                return ret;

        /* Transfer the contents */
        iowrite32_rep(nfc->regs + NDDB, data, FIFO_REP(data_len));
        iowrite32_rep(nfc->regs + NDDB, spare, FIFO_REP(spare_len));

        return 0;
}

static int marvell_nfc_hw_ecc_bch_write_page(struct nand_chip *chip,
                                             const u8 *buf,
                                             int oob_required, int page)
{
        const struct nand_sdr_timings *sdr =
                nand_get_sdr_timings(nand_get_interface_config(chip));
        struct mtd_info *mtd = nand_to_mtd(chip);
        const struct marvell_hw_ecc_layout *lt = to_marvell_nand(chip)->layout;
        const u8 *data = buf;
        const u8 *spare = chip->oob_poi;
        int data_len = lt->data_bytes;
        int spare_len = lt->spare_bytes;
        int chunk, ret;

        marvell_nfc_select_target(chip, chip->cur_cs);

        /* Spare data will be written anyway, so clear it to avoid garbage */
        if (!oob_required)
                memset(chip->oob_poi, 0xFF, mtd->oobsize);

        marvell_nfc_enable_hw_ecc(chip);

        for (chunk = 0; chunk < lt->nchunks; chunk++) {
                if (chunk >= lt->full_chunk_cnt) {
                        data_len = lt->last_data_bytes;
                        spare_len = lt->last_spare_bytes;
                }

                marvell_nfc_hw_ecc_bch_write_chunk(chip, chunk, data, data_len,
                                                   spare, spare_len, page);
                data += data_len;
                spare += spare_len;

                /*
                 * Waiting only for CMDD or PAGED is not enough, ECC are
                 * partially written. No flag is set once the operation is
                 * really finished but the ND_RUN bit is cleared, so wait for it
                 * before stepping into the next command.
                 */
                marvell_nfc_wait_ndrun(chip);
        }

        ret = marvell_nfc_wait_op(chip, PSEC_TO_MSEC(sdr->tPROG_max));

        marvell_nfc_disable_hw_ecc(chip);

        if (ret)
                return ret;

        return 0;
}

static int marvell_nfc_hw_ecc_bch_write_oob_raw(struct nand_chip *chip,
                                                int page)
{
        struct mtd_info *mtd = nand_to_mtd(chip);
        u8 *buf = nand_get_data_buf(chip);

        memset(buf, 0xFF, mtd->writesize);

        return chip->ecc.write_page_raw(chip, buf, true, page);
}

static int marvell_nfc_hw_ecc_bch_write_oob(struct nand_chip *chip, int page)
{
        struct mtd_info *mtd = nand_to_mtd(chip);
        u8 *buf = nand_get_data_buf(chip);

        memset(buf, 0xFF, mtd->writesize);

        return chip->ecc.write_page(chip, buf, true, page);
}

/* NAND framework ->exec_op() hooks and related helpers */
static void marvell_nfc_parse_instructions(struct nand_chip *chip,
                                           const struct nand_subop *subop,
                                           struct marvell_nfc_op *nfc_op)
{
        const struct nand_op_instr *instr = NULL;
        struct marvell_nfc *nfc = to_marvell_nfc(chip->controller);
        bool first_cmd = true;
        unsigned int op_id;
        int i;

        /* Reset the input structure as most of its fields will be OR'ed */
        memset(nfc_op, 0, sizeof(struct marvell_nfc_op));

        for (op_id = 0; op_id < subop->ninstrs; op_id++) {
                unsigned int offset, naddrs;
                const u8 *addrs;
                int len;

                instr = &subop->instrs[op_id];

                switch (instr->type) {
                case NAND_OP_CMD_INSTR:
                        if (first_cmd)
                                nfc_op->ndcb[0] |=
                                        NDCB0_CMD1(instr->ctx.cmd.opcode);
                        else
                                nfc_op->ndcb[0] |=
                                        NDCB0_CMD2(instr->ctx.cmd.opcode) |
                                        NDCB0_DBC;

                        nfc_op->cle_ale_delay_ns = instr->delay_ns;
                        first_cmd = false;
                        break;

                case NAND_OP_ADDR_INSTR:
                        offset = nand_subop_get_addr_start_off(subop, op_id);
                        naddrs = nand_subop_get_num_addr_cyc(subop, op_id);
                        addrs = &instr->ctx.addr.addrs[offset];

                        nfc_op->ndcb[0] |= NDCB0_ADDR_CYC(naddrs);

                        for (i = 0; i < min_t(unsigned int, 4, naddrs); i++)
                                nfc_op->ndcb[1] |= addrs[i] << (8 * i);

                        if (naddrs >= 5)
                                nfc_op->ndcb[2] |= NDCB2_ADDR5_CYC(addrs[4]);
                        if (naddrs >= 6)
                                nfc_op->ndcb[3] |= NDCB3_ADDR6_CYC(addrs[5]);
                        if (naddrs == 7)
                                nfc_op->ndcb[3] |= NDCB3_ADDR7_CYC(addrs[6]);

                        nfc_op->cle_ale_delay_ns = instr->delay_ns;
                        break;

                case NAND_OP_DATA_IN_INSTR:
                        nfc_op->data_instr = instr;
                        nfc_op->data_instr_idx = op_id;
                        nfc_op->ndcb[0] |= NDCB0_CMD_TYPE(TYPE_READ);
                        if (nfc->caps->is_nfcv2) {
                                nfc_op->ndcb[0] |=
                                        NDCB0_CMD_XTYPE(XTYPE_MONOLITHIC_RW) |
                                        NDCB0_LEN_OVRD;
                                len = nand_subop_get_data_len(subop, op_id);
                                nfc_op->ndcb[3] |= round_up(len, FIFO_DEPTH);
                        }
                        nfc_op->data_delay_ns = instr->delay_ns;
                        break;

                case NAND_OP_DATA_OUT_INSTR:
                        nfc_op->data_instr = instr;
                        nfc_op->data_instr_idx = op_id;
                        nfc_op->ndcb[0] |= NDCB0_CMD_TYPE(TYPE_WRITE);
                        if (nfc->caps->is_nfcv2) {
                                nfc_op->ndcb[0] |=
                                        NDCB0_CMD_XTYPE(XTYPE_MONOLITHIC_RW) |
                                        NDCB0_LEN_OVRD;
                                len = nand_subop_get_data_len(subop, op_id);
                                nfc_op->ndcb[3] |= round_up(len, FIFO_DEPTH);
                        }
                        nfc_op->data_delay_ns = instr->delay_ns;
                        break;

                case NAND_OP_WAITRDY_INSTR:
                        nfc_op->rdy_timeout_ms = instr->ctx.waitrdy.timeout_ms;
                        nfc_op->rdy_delay_ns = instr->delay_ns;
                        break;
                }
        }
}

static int marvell_nfc_xfer_data_pio(struct nand_chip *chip,
                                     const struct nand_subop *subop,
                                     struct marvell_nfc_op *nfc_op)
{
        struct marvell_nfc *nfc = to_marvell_nfc(chip->controller);
        const struct nand_op_instr *instr = nfc_op->data_instr;
        unsigned int op_id = nfc_op->data_instr_idx;
        unsigned int len = nand_subop_get_data_len(subop, op_id);
        unsigned int offset = nand_subop_get_data_start_off(subop, op_id);
        bool reading = (instr->type == NAND_OP_DATA_IN_INSTR);
        int ret;

        if (instr->ctx.data.force_8bit)
                marvell_nfc_force_byte_access(chip, true);

        if (reading) {
                u8 *in = instr->ctx.data.buf.in + offset;

                ret = marvell_nfc_xfer_data_in_pio(nfc, in, len);
        } else {
                const u8 *out = instr->ctx.data.buf.out + offset;

                ret = marvell_nfc_xfer_data_out_pio(nfc, out, len);
        }

        if (instr->ctx.data.force_8bit)
                marvell_nfc_force_byte_access(chip, false);

        return ret;
}

static int marvell_nfc_monolithic_access_exec(struct nand_chip *chip,
                                              const struct nand_subop *subop)
{
        struct marvell_nfc_op nfc_op;
        bool reading;
        int ret;

        marvell_nfc_parse_instructions(chip, subop, &nfc_op);
        reading = (nfc_op.data_instr->type == NAND_OP_DATA_IN_INSTR);

        ret = marvell_nfc_prepare_cmd(chip);
        if (ret)
                return ret;

        marvell_nfc_send_cmd(chip, &nfc_op);
        ret = marvell_nfc_end_cmd(chip, NDSR_RDDREQ | NDSR_WRDREQ,
                                  "RDDREQ/WRDREQ while draining raw data");
        if (ret)
                return ret;

        cond_delay(nfc_op.cle_ale_delay_ns);

        if (reading) {
                if (nfc_op.rdy_timeout_ms) {
                        ret = marvell_nfc_wait_op(chip, nfc_op.rdy_timeout_ms);
                        if (ret)
                                return ret;
                }

                cond_delay(nfc_op.rdy_delay_ns);
        }

        marvell_nfc_xfer_data_pio(chip, subop, &nfc_op);
        ret = marvell_nfc_wait_cmdd(chip);
        if (ret)
                return ret;

        cond_delay(nfc_op.data_delay_ns);

        if (!reading) {
                if (nfc_op.rdy_timeout_ms) {
                        ret = marvell_nfc_wait_op(chip, nfc_op.rdy_timeout_ms);
                        if (ret)
                                return ret;
                }

                cond_delay(nfc_op.rdy_delay_ns);
        }

        /*
         * NDCR ND_RUN bit should be cleared automatically at the end of each
         * operation but experience shows that the behavior is buggy when it
         * comes to writes (with LEN_OVRD). Clear it by hand in this case.
         */
        if (!reading) {
                struct marvell_nfc *nfc = to_marvell_nfc(chip->controller);

                writel_relaxed(readl(nfc->regs + NDCR) & ~NDCR_ND_RUN,
                               nfc->regs + NDCR);
        }

        return 0;
}

static int marvell_nfc_naked_access_exec(struct nand_chip *chip,
                                         const struct nand_subop *subop)
{
        struct marvell_nfc_op nfc_op;
        int ret;

        marvell_nfc_parse_instructions(chip, subop, &nfc_op);

        /*
         * Naked access are different in that they need to be flagged as naked
         * by the controller. Reset the controller registers fields that inform
         * on the type and refill them according to the ongoing operation.
         */
        nfc_op.ndcb[0] &= ~(NDCB0_CMD_TYPE(TYPE_MASK) |
                            NDCB0_CMD_XTYPE(XTYPE_MASK));
        switch (subop->instrs[0].type) {
        case NAND_OP_CMD_INSTR:
                nfc_op.ndcb[0] |= NDCB0_CMD_TYPE(TYPE_NAKED_CMD);
                break;
        case NAND_OP_ADDR_INSTR:
                nfc_op.ndcb[0] |= NDCB0_CMD_TYPE(TYPE_NAKED_ADDR);
                break;
        case NAND_OP_DATA_IN_INSTR:
                nfc_op.ndcb[0] |= NDCB0_CMD_TYPE(TYPE_READ) |
                                  NDCB0_CMD_XTYPE(XTYPE_LAST_NAKED_RW);
                break;
        case NAND_OP_DATA_OUT_INSTR:
                nfc_op.ndcb[0] |= NDCB0_CMD_TYPE(TYPE_WRITE) |
                                  NDCB0_CMD_XTYPE(XTYPE_LAST_NAKED_RW);
                break;
        default:
                /* This should never happen */
                break;
        }

        ret = marvell_nfc_prepare_cmd(chip);
        if (ret)
                return ret;

        marvell_nfc_send_cmd(chip, &nfc_op);

        if (!nfc_op.data_instr) {
                ret = marvell_nfc_wait_cmdd(chip);
                cond_delay(nfc_op.cle_ale_delay_ns);
                return ret;
        }

        ret = marvell_nfc_end_cmd(chip, NDSR_RDDREQ | NDSR_WRDREQ,
                                  "RDDREQ/WRDREQ while draining raw data");
        if (ret)
                return ret;

        marvell_nfc_xfer_data_pio(chip, subop, &nfc_op);
        ret = marvell_nfc_wait_cmdd(chip);
        if (ret)
                return ret;

        /*
         * NDCR ND_RUN bit should be cleared automatically at the end of each
         * operation but experience shows that the behavior is buggy when it
         * comes to writes (with LEN_OVRD). Clear it by hand in this case.
         */
        if (subop->instrs[0].type == NAND_OP_DATA_OUT_INSTR) {
                struct marvell_nfc *nfc = to_marvell_nfc(chip->controller);

                writel_relaxed(readl(nfc->regs + NDCR) & ~NDCR_ND_RUN,
                               nfc->regs + NDCR);
        }

        return 0;
}

static int marvell_nfc_naked_waitrdy_exec(struct nand_chip *chip,
                                          const struct nand_subop *subop)
{
        struct marvell_nfc_op nfc_op;
        int ret;

        marvell_nfc_parse_instructions(chip, subop, &nfc_op);

        ret = marvell_nfc_wait_op(chip, nfc_op.rdy_timeout_ms);
        cond_delay(nfc_op.rdy_delay_ns);

        return ret;
}

static int marvell_nfc_read_id_type_exec(struct nand_chip *chip,
                                         const struct nand_subop *subop)
{
        struct marvell_nfc_op nfc_op;
        int ret;

        marvell_nfc_parse_instructions(chip, subop, &nfc_op);
        nfc_op.ndcb[0] &= ~NDCB0_CMD_TYPE(TYPE_READ);
        nfc_op.ndcb[0] |= NDCB0_CMD_TYPE(TYPE_READ_ID);

        ret = marvell_nfc_prepare_cmd(chip);
        if (ret)
                return ret;

        marvell_nfc_send_cmd(chip, &nfc_op);
        ret = marvell_nfc_end_cmd(chip, NDSR_RDDREQ,
                                  "RDDREQ while reading ID");
        if (ret)
                return ret;

        cond_delay(nfc_op.cle_ale_delay_ns);

        if (nfc_op.rdy_timeout_ms) {
                ret = marvell_nfc_wait_op(chip, nfc_op.rdy_timeout_ms);
                if (ret)
                        return ret;
        }

        cond_delay(nfc_op.rdy_delay_ns);

        marvell_nfc_xfer_data_pio(chip, subop, &nfc_op);
        ret = marvell_nfc_wait_cmdd(chip);
        if (ret)
                return ret;

        cond_delay(nfc_op.data_delay_ns);

        return 0;
}

static int marvell_nfc_read_status_exec(struct nand_chip *chip,
                                        const struct nand_subop *subop)
{
        struct marvell_nfc_op nfc_op;
        int ret;

        marvell_nfc_parse_instructions(chip, subop, &nfc_op);
        nfc_op.ndcb[0] &= ~NDCB0_CMD_TYPE(TYPE_READ);
        nfc_op.ndcb[0] |= NDCB0_CMD_TYPE(TYPE_STATUS);

        ret = marvell_nfc_prepare_cmd(chip);
        if (ret)
                return ret;

        marvell_nfc_send_cmd(chip, &nfc_op);
        ret = marvell_nfc_end_cmd(chip, NDSR_RDDREQ,
                                  "RDDREQ while reading status");
        if (ret)
                return ret;

        cond_delay(nfc_op.cle_ale_delay_ns);

        if (nfc_op.rdy_timeout_ms) {
                ret = marvell_nfc_wait_op(chip, nfc_op.rdy_timeout_ms);
                if (ret)
                        return ret;
        }

        cond_delay(nfc_op.rdy_delay_ns);

        marvell_nfc_xfer_data_pio(chip, subop, &nfc_op);
        ret = marvell_nfc_wait_cmdd(chip);
        if (ret)
                return ret;

        cond_delay(nfc_op.data_delay_ns);

        return 0;
}

static int marvell_nfc_reset_cmd_type_exec(struct nand_chip *chip,
                                           const struct nand_subop *subop)
{
        struct marvell_nfc_op nfc_op;
        int ret;

        marvell_nfc_parse_instructions(chip, subop, &nfc_op);
        nfc_op.ndcb[0] |= NDCB0_CMD_TYPE(TYPE_RESET);

        ret = marvell_nfc_prepare_cmd(chip);
        if (ret)
                return ret;

        marvell_nfc_send_cmd(chip, &nfc_op);
        ret = marvell_nfc_wait_cmdd(chip);
        if (ret)
                return ret;

        cond_delay(nfc_op.cle_ale_delay_ns);

        ret = marvell_nfc_wait_op(chip, nfc_op.rdy_timeout_ms);
        if (ret)
                return ret;

        cond_delay(nfc_op.rdy_delay_ns);

        return 0;
}

static int marvell_nfc_erase_cmd_type_exec(struct nand_chip *chip,
                                           const struct nand_subop *subop)
{
        struct marvell_nfc_op nfc_op;
        int ret;

        marvell_nfc_parse_instructions(chip, subop, &nfc_op);
        nfc_op.ndcb[0] |= NDCB0_CMD_TYPE(TYPE_ERASE);

        ret = marvell_nfc_prepare_cmd(chip);
        if (ret)
                return ret;

        marvell_nfc_send_cmd(chip, &nfc_op);
        ret = marvell_nfc_wait_cmdd(chip);
        if (ret)
                return ret;

        cond_delay(nfc_op.cle_ale_delay_ns);

        ret = marvell_nfc_wait_op(chip, nfc_op.rdy_timeout_ms);
        if (ret)
                return ret;

        cond_delay(nfc_op.rdy_delay_ns);

        return 0;
}

static const struct nand_op_parser marvell_nfcv2_op_parser = NAND_OP_PARSER(
        /* Monolithic reads/writes */
        NAND_OP_PARSER_PATTERN(
                marvell_nfc_monolithic_access_exec,
                NAND_OP_PARSER_PAT_CMD_ELEM(false),
                NAND_OP_PARSER_PAT_ADDR_ELEM(true, MAX_ADDRESS_CYC_NFCV2),
                NAND_OP_PARSER_PAT_CMD_ELEM(true),
                NAND_OP_PARSER_PAT_WAITRDY_ELEM(true),
                NAND_OP_PARSER_PAT_DATA_IN_ELEM(false, MAX_CHUNK_SIZE)),
        NAND_OP_PARSER_PATTERN(
                marvell_nfc_monolithic_access_exec,
                NAND_OP_PARSER_PAT_CMD_ELEM(false),
                NAND_OP_PARSER_PAT_ADDR_ELEM(false, MAX_ADDRESS_CYC_NFCV2),
                NAND_OP_PARSER_PAT_DATA_OUT_ELEM(false, MAX_CHUNK_SIZE),
                NAND_OP_PARSER_PAT_CMD_ELEM(true),
                NAND_OP_PARSER_PAT_WAITRDY_ELEM(true)),
        /* Naked commands */
        NAND_OP_PARSER_PATTERN(
                marvell_nfc_naked_access_exec,
                NAND_OP_PARSER_PAT_CMD_ELEM(false)),
        NAND_OP_PARSER_PATTERN(
                marvell_nfc_naked_access_exec,
                NAND_OP_PARSER_PAT_ADDR_ELEM(false, MAX_ADDRESS_CYC_NFCV2)),
        NAND_OP_PARSER_PATTERN(
                marvell_nfc_naked_access_exec,
                NAND_OP_PARSER_PAT_DATA_IN_ELEM(false, MAX_CHUNK_SIZE)),
        NAND_OP_PARSER_PATTERN(
                marvell_nfc_naked_access_exec,
                NAND_OP_PARSER_PAT_DATA_OUT_ELEM(false, MAX_CHUNK_SIZE)),
        NAND_OP_PARSER_PATTERN(
                marvell_nfc_naked_waitrdy_exec,
                NAND_OP_PARSER_PAT_WAITRDY_ELEM(false)),
        );

static const struct nand_op_parser marvell_nfcv1_op_parser = NAND_OP_PARSER(
        /* Naked commands not supported, use a function for each pattern */
        NAND_OP_PARSER_PATTERN(
                marvell_nfc_read_id_type_exec,
                NAND_OP_PARSER_PAT_CMD_ELEM(false),
                NAND_OP_PARSER_PAT_ADDR_ELEM(false, MAX_ADDRESS_CYC_NFCV1),
                NAND_OP_PARSER_PAT_DATA_IN_ELEM(false, 8)),
        NAND_OP_PARSER_PATTERN(
                marvell_nfc_erase_cmd_type_exec,
                NAND_OP_PARSER_PAT_CMD_ELEM(false),
                NAND_OP_PARSER_PAT_ADDR_ELEM(false, MAX_ADDRESS_CYC_NFCV1),
                NAND_OP_PARSER_PAT_CMD_ELEM(false),
                NAND_OP_PARSER_PAT_WAITRDY_ELEM(false)),
        NAND_OP_PARSER_PATTERN(
                marvell_nfc_read_status_exec,
                NAND_OP_PARSER_PAT_CMD_ELEM(false),
                NAND_OP_PARSER_PAT_DATA_IN_ELEM(false, 1)),
        NAND_OP_PARSER_PATTERN(
                marvell_nfc_reset_cmd_type_exec,
                NAND_OP_PARSER_PAT_CMD_ELEM(false),
                NAND_OP_PARSER_PAT_WAITRDY_ELEM(false)),
        NAND_OP_PARSER_PATTERN(
                marvell_nfc_naked_waitrdy_exec,
                NAND_OP_PARSER_PAT_WAITRDY_ELEM(false)),
        );

static int marvell_nfc_exec_op(struct nand_chip *chip,
                               const struct nand_operation *op,
                               bool check_only)
{
        struct marvell_nfc *nfc = to_marvell_nfc(chip->controller);

        if (!check_only)
                marvell_nfc_select_target(chip, op->cs);

        if (nfc->caps->is_nfcv2)
                return nand_op_parser_exec_op(chip, &marvell_nfcv2_op_parser,
                                              op, check_only);
        else
                return nand_op_parser_exec_op(chip, &marvell_nfcv1_op_parser,
                                              op, check_only);
}

/*
 * Layouts were broken in old pxa3xx_nand driver, these are supposed to be
 * usable.
 */
static int marvell_nand_ooblayout_ecc(struct mtd_info *mtd, int section,
                                      struct mtd_oob_region *oobregion)
{
        struct nand_chip *chip = mtd_to_nand(mtd);
        const struct marvell_hw_ecc_layout *lt = to_marvell_nand(chip)->layout;

        if (section)
                return -ERANGE;

        oobregion->length = (lt->full_chunk_cnt * lt->ecc_bytes) +
                            lt->last_ecc_bytes;
        oobregion->offset = mtd->oobsize - oobregion->length;

        return 0;
}

static int marvell_nand_ooblayout_free(struct mtd_info *mtd, int section,
                                       struct mtd_oob_region *oobregion)
{
        struct nand_chip *chip = mtd_to_nand(mtd);
        const struct marvell_hw_ecc_layout *lt = to_marvell_nand(chip)->layout;

        if (section)
                return -ERANGE;

        /*
         * Bootrom looks in bytes 0 & 5 for bad blocks for the
         * 4KB page / 4bit BCH combination.
         */
        if (mtd->writesize == SZ_4K && lt->data_bytes == SZ_2K)
                oobregion->offset = 6;
        else
                oobregion->offset = 2;

        oobregion->length = (lt->full_chunk_cnt * lt->spare_bytes) +
                            lt->last_spare_bytes - oobregion->offset;

        return 0;
}

static const struct mtd_ooblayout_ops marvell_nand_ooblayout_ops = {
        .ecc = marvell_nand_ooblayout_ecc,
        .free = marvell_nand_ooblayout_free,
};

static int marvell_nand_hw_ecc_controller_init(struct mtd_info *mtd,
                                               struct nand_ecc_ctrl *ecc)
{
        struct nand_chip *chip = mtd_to_nand(mtd);
        struct marvell_nfc *nfc = to_marvell_nfc(chip->controller);
        const struct marvell_hw_ecc_layout *l;
        int i;

        if (!nfc->caps->is_nfcv2 &&
            (mtd->writesize + mtd->oobsize > MAX_CHUNK_SIZE)) {
                dev_err(nfc->dev,
                        "NFCv1: writesize (%d) cannot be bigger than a chunk (%d)\n",
                        mtd->writesize, MAX_CHUNK_SIZE - mtd->oobsize);
                return -ENOTSUPP;
        }

        to_marvell_nand(chip)->layout = NULL;
        for (i = 0; i < ARRAY_SIZE(marvell_nfc_layouts); i++) {
                l = &marvell_nfc_layouts[i];
                if (mtd->writesize == l->writesize &&
                    ecc->size == l->chunk && ecc->strength == l->strength) {
                        to_marvell_nand(chip)->layout = l;
                        break;
                }
        }

        if (!to_marvell_nand(chip)->layout ||
            (!nfc->caps->is_nfcv2 && ecc->strength > 1)) {
                dev_err(nfc->dev,
                        "ECC strength %d at page size %d is not supported\n",
                        ecc->strength, mtd->writesize);
                return -ENOTSUPP;
        }

        /* Special care for the layout 2k/8-bit/512B  */
        if (l->writesize == 2048 && l->strength == 8) {
                if (mtd->oobsize < 128) {
                        dev_err(nfc->dev, "Requested layout needs at least 128 OOB bytes\n");
                        return -ENOTSUPP;
                } else {
                        chip->bbt_options |= NAND_BBT_NO_OOB_BBM;
                }
        }

        mtd_set_ooblayout(mtd, &marvell_nand_ooblayout_ops);
        ecc->steps = l->nchunks;
        ecc->size = l->data_bytes;

        if (ecc->strength == 1) {
                chip->ecc.algo = NAND_ECC_ALGO_HAMMING;
                ecc->read_page_raw = marvell_nfc_hw_ecc_hmg_read_page_raw;
                ecc->read_page = marvell_nfc_hw_ecc_hmg_read_page;
                ecc->read_oob_raw = marvell_nfc_hw_ecc_hmg_read_oob_raw;
                ecc->read_oob = ecc->read_oob_raw;
                ecc->write_page_raw = marvell_nfc_hw_ecc_hmg_write_page_raw;
                ecc->write_page = marvell_nfc_hw_ecc_hmg_write_page;
                ecc->write_oob_raw = marvell_nfc_hw_ecc_hmg_write_oob_raw;
                ecc->write_oob = ecc->write_oob_raw;
        } else {
                chip->ecc.algo = NAND_ECC_ALGO_BCH;
                ecc->strength = 16;
                ecc->read_page_raw = marvell_nfc_hw_ecc_bch_read_page_raw;
                ecc->read_page = marvell_nfc_hw_ecc_bch_read_page;
                ecc->read_oob_raw = marvell_nfc_hw_ecc_bch_read_oob_raw;
                ecc->read_oob = marvell_nfc_hw_ecc_bch_read_oob;
                ecc->write_page_raw = marvell_nfc_hw_ecc_bch_write_page_raw;
                ecc->write_page = marvell_nfc_hw_ecc_bch_write_page;
                ecc->write_oob_raw = marvell_nfc_hw_ecc_bch_write_oob_raw;
                ecc->write_oob = marvell_nfc_hw_ecc_bch_write_oob;
        }

        return 0;
}

static int marvell_nand_ecc_init(struct mtd_info *mtd,
                                 struct nand_ecc_ctrl *ecc)
{
        struct nand_chip *chip = mtd_to_nand(mtd);
        const struct nand_ecc_props *requirements =
                nanddev_get_ecc_requirements(&chip->base);
        struct marvell_nfc *nfc = to_marvell_nfc(chip->controller);
        int ret;

        if (ecc->engine_type != NAND_ECC_ENGINE_TYPE_NONE &&
            (!ecc->size || !ecc->strength)) {
                if (requirements->step_size && requirements->strength) {
                        ecc->size = requirements->step_size;
                        ecc->strength = requirements->strength;
                } else {
                        dev_info(nfc->dev,
                                 "No minimum ECC strength, using 1b/512B\n");
                        ecc->size = 512;
                        ecc->strength = 1;
                }
        }

        switch (ecc->engine_type) {
        case NAND_ECC_ENGINE_TYPE_ON_HOST:
                ret = marvell_nand_hw_ecc_controller_init(mtd, ecc);
                if (ret)
                        return ret;
                break;
        case NAND_ECC_ENGINE_TYPE_NONE:
        case NAND_ECC_ENGINE_TYPE_SOFT:
        case NAND_ECC_ENGINE_TYPE_ON_DIE:
                if (!nfc->caps->is_nfcv2 && mtd->writesize != SZ_512 &&
                    mtd->writesize != SZ_2K) {
                        dev_err(nfc->dev, "NFCv1 cannot write %d bytes pages\n",
                                mtd->writesize);
                        return -EINVAL;
                }
                break;
        default:
                return -EINVAL;
        }

        return 0;
}

static u8 bbt_pattern[] = {'M', 'V', 'B', 'b', 't', '0' };
static u8 bbt_mirror_pattern[] = {'1', 't', 'b', 'B', 'V', 'M' };

static struct nand_bbt_descr bbt_main_descr = {
        .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE |
                   NAND_BBT_2BIT | NAND_BBT_VERSION,
        .offs = 8,
        .len = 6,
        .veroffs = 14,
        .maxblocks = 8, /* Last 8 blocks in each chip */
        .pattern = bbt_pattern
};

static struct nand_bbt_descr bbt_mirror_descr = {
        .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE |
                   NAND_BBT_2BIT | NAND_BBT_VERSION,
        .offs = 8,
        .len = 6,
        .veroffs = 14,
        .maxblocks = 8, /* Last 8 blocks in each chip */
        .pattern = bbt_mirror_pattern
};

static int marvell_nfc_setup_interface(struct nand_chip *chip, int chipnr,
                                       const struct nand_interface_config *conf)
{
        struct marvell_nand_chip *marvell_nand = to_marvell_nand(chip);
        struct marvell_nfc *nfc = to_marvell_nfc(chip->controller);
        unsigned int period_ns = 1000000000 / clk_get_rate(nfc->core_clk) * 2;
        const struct nand_sdr_timings *sdr;
        struct marvell_nfc_timings nfc_tmg;
        int read_delay;

        sdr = nand_get_sdr_timings(conf);
        if (IS_ERR(sdr))
                return PTR_ERR(sdr);

        /*
         * SDR timings are given in pico-seconds while NFC timings must be
         * expressed in NAND controller clock cycles, which is half of the
         * frequency of the accessible ECC clock retrieved by clk_get_rate().
         * This is not written anywhere in the datasheet but was observed
         * with an oscilloscope.
         *
         * NFC datasheet gives equations from which thoses calculations
         * are derived, they tend to be slightly more restrictives than the
         * given core timings and may improve the overall speed.
         */
        nfc_tmg.tRP = TO_CYCLES(DIV_ROUND_UP(sdr->tRC_min, 2), period_ns) - 1;
        nfc_tmg.tRH = nfc_tmg.tRP;
        nfc_tmg.tWP = TO_CYCLES(DIV_ROUND_UP(sdr->tWC_min, 2), period_ns) - 1;
        nfc_tmg.tWH = nfc_tmg.tWP;
        nfc_tmg.tCS = TO_CYCLES(sdr->tCS_min, period_ns);
        nfc_tmg.tCH = TO_CYCLES(sdr->tCH_min, period_ns) - 1;
        nfc_tmg.tADL = TO_CYCLES(sdr->tADL_min, period_ns);
        /*
         * Read delay is the time of propagation from SoC pins to NFC internal
         * logic. With non-EDO timings, this is MIN_RD_DEL_CNT clock cycles. In
         * EDO mode, an additional delay of tRH must be taken into account so
         * the data is sampled on the falling edge instead of the rising edge.
         */
        read_delay = sdr->tRC_min >= 30000 ?
                MIN_RD_DEL_CNT : MIN_RD_DEL_CNT + nfc_tmg.tRH;

        nfc_tmg.tAR = TO_CYCLES(sdr->tAR_min, period_ns);
        /*
         * tWHR and tRHW are supposed to be read to write delays (and vice
         * versa) but in some cases, ie. when doing a change column, they must
         * be greater than that to be sure tCCS delay is respected.
         */
        nfc_tmg.tWHR = TO_CYCLES(max_t(int, sdr->tWHR_min, sdr->tCCS_min),
                                 period_ns) - 2,
        nfc_tmg.tRHW = TO_CYCLES(max_t(int, sdr->tRHW_min, sdr->tCCS_min),
                                 period_ns);

        /*
         * NFCv2: Use WAIT_MODE (wait for RB line), do not rely only on delays.
         * NFCv1: No WAIT_MODE, tR must be maximal.
         */
        if (nfc->caps->is_nfcv2) {
                nfc_tmg.tR = TO_CYCLES(sdr->tWB_max, period_ns);
        } else {
                nfc_tmg.tR = TO_CYCLES64(sdr->tWB_max + sdr->tR_max,
                                         period_ns);
                if (nfc_tmg.tR + 3 > nfc_tmg.tCH)
                        nfc_tmg.tR = nfc_tmg.tCH - 3;
                else
                        nfc_tmg.tR = 0;
        }

        if (chipnr < 0)
                return 0;

        marvell_nand->ndtr0 =
                NDTR0_TRP(nfc_tmg.tRP) |
                NDTR0_TRH(nfc_tmg.tRH) |
                NDTR0_ETRP(nfc_tmg.tRP) |
                NDTR0_TWP(nfc_tmg.tWP) |
                NDTR0_TWH(nfc_tmg.tWH) |
                NDTR0_TCS(nfc_tmg.tCS) |
                NDTR0_TCH(nfc_tmg.tCH);

        marvell_nand->ndtr1 =
                NDTR1_TAR(nfc_tmg.tAR) |
                NDTR1_TWHR(nfc_tmg.tWHR) |
                NDTR1_TR(nfc_tmg.tR);

        if (nfc->caps->is_nfcv2) {
                marvell_nand->ndtr0 |=
                        NDTR0_RD_CNT_DEL(read_delay) |
                        NDTR0_SELCNTR |
                        NDTR0_TADL(nfc_tmg.tADL);

                marvell_nand->ndtr1 |=
                        NDTR1_TRHW(nfc_tmg.tRHW) |
                        NDTR1_WAIT_MODE;
        }

        return 0;
}

static int marvell_nand_attach_chip(struct nand_chip *chip)
{
        struct mtd_info *mtd = nand_to_mtd(chip);
        struct marvell_nand_chip *marvell_nand = to_marvell_nand(chip);
        struct marvell_nfc *nfc = to_marvell_nfc(chip->controller);
        struct pxa3xx_nand_platform_data *pdata = dev_get_platdata(nfc->dev);
        int ret;

        if (pdata && pdata->flash_bbt)
                chip->bbt_options |= NAND_BBT_USE_FLASH;

        if (chip->bbt_options & NAND_BBT_USE_FLASH) {
                /*
                 * We'll use a bad block table stored in-flash and don't
                 * allow writing the bad block marker to the flash.
                 */
                chip->bbt_options |= NAND_BBT_NO_OOB_BBM;
                chip->bbt_td = &bbt_main_descr;
                chip->bbt_md = &bbt_mirror_descr;
        }

        /* Save the chip-specific fields of NDCR */
        marvell_nand->ndcr = NDCR_PAGE_SZ(mtd->writesize);
        if (chip->options & NAND_BUSWIDTH_16)
                marvell_nand->ndcr |= NDCR_DWIDTH_M | NDCR_DWIDTH_C;

        /*
         * On small page NANDs, only one cycle is needed to pass the
         * column address.
         */
        if (mtd->writesize <= 512) {
                marvell_nand->addr_cyc = 1;
        } else {
                marvell_nand->addr_cyc = 2;
                marvell_nand->ndcr |= NDCR_RA_START;
        }

        /*
         * Now add the number of cycles needed to pass the row
         * address.
         *
         * Addressing a chip using CS 2 or 3 should also need the third row
         * cycle but due to inconsistance in the documentation and lack of
         * hardware to test this situation, this case is not supported.
         */
        if (chip->options & NAND_ROW_ADDR_3)
                marvell_nand->addr_cyc += 3;
        else
                marvell_nand->addr_cyc += 2;

        if (pdata) {
                chip->ecc.size = pdata->ecc_step_size;
                chip->ecc.strength = pdata->ecc_strength;
        }

        ret = marvell_nand_ecc_init(mtd, &chip->ecc);
        if (ret) {
                dev_err(nfc->dev, "ECC init failed: %d\n", ret);
                return ret;
        }

        if (chip->ecc.engine_type == NAND_ECC_ENGINE_TYPE_ON_HOST) {
                /*
                 * Subpage write not available with hardware ECC, prohibit also
                 * subpage read as in userspace subpage access would still be
                 * allowed and subpage write, if used, would lead to numerous
                 * uncorrectable ECC errors.
                 */
                chip->options |= NAND_NO_SUBPAGE_WRITE;
        }

        if (pdata || nfc->caps->legacy_of_bindings) {
                /*
                 * We keep the MTD name unchanged to avoid breaking platforms
                 * where the MTD cmdline parser is used and the bootloader
                 * has not been updated to use the new naming scheme.
                 */
                mtd->name = "pxa3xx_nand-0";
        } else if (!mtd->name) {
                /*
                 * If the new bindings are used and the bootloader has not been
                 * updated to pass a new mtdparts parameter on the cmdline, you
                 * should define the following property in your NAND node, ie:
                 *
                 *      label = "main-storage";
                 *
                 * This way, mtd->name will be set by the core when
                 * nand_set_flash_node() is called.
                 */
                mtd->name = devm_kasprintf(nfc->dev, GFP_KERNEL,
                                           "%s:nand.%d", dev_name(nfc->dev),
                                           marvell_nand->sels[0].cs);
                if (!mtd->name) {
                        dev_err(nfc->dev, "Failed to allocate mtd->name\n");
                        return -ENOMEM;
                }
        }

        return 0;
}

static const struct nand_controller_ops marvell_nand_controller_ops = {
        .attach_chip = marvell_nand_attach_chip,
        .exec_op = marvell_nfc_exec_op,
        .setup_interface = marvell_nfc_setup_interface,
};

static int marvell_nand_chip_init(struct device *dev, struct marvell_nfc *nfc,
                                  struct device_node *np)
{
        struct pxa3xx_nand_platform_data *pdata = dev_get_platdata(dev);
        struct marvell_nand_chip *marvell_nand;
        struct mtd_info *mtd;
        struct nand_chip *chip;
        int nsels, ret, i;
        u32 cs, rb;

        /*
         * The legacy "num-cs" property indicates the number of CS on the only
         * chip connected to the controller (legacy bindings does not support
         * more than one chip). The CS and RB pins are always the #0.
         *
         * When not using legacy bindings, a couple of "reg" and "nand-rb"
         * properties must be filled. For each chip, expressed as a subnode,
         * "reg" points to the CS lines and "nand-rb" to the RB line.
         */
        if (pdata || nfc->caps->legacy_of_bindings) {
                nsels = 1;
        } else {
                nsels = of_property_count_elems_of_size(np, "reg", sizeof(u32));
                if (nsels <= 0) {
                        dev_err(dev, "missing/invalid reg property\n");
                        return -EINVAL;
                }
        }

        /* Alloc the nand chip structure */
        marvell_nand = devm_kzalloc(dev,
                                    struct_size(marvell_nand, sels, nsels),
                                    GFP_KERNEL);
        if (!marvell_nand) {
                dev_err(dev, "could not allocate chip structure\n");
                return -ENOMEM;
        }

        marvell_nand->nsels = nsels;
        marvell_nand->selected_die = -1;

        for (i = 0; i < nsels; i++) {
                if (pdata || nfc->caps->legacy_of_bindings) {
                        /*
                         * Legacy bindings use the CS lines in natural
                         * order (0, 1, ...)
                         */
                        cs = i;
                } else {
                        /* Retrieve CS id */
                        ret = of_property_read_u32_index(np, "reg", i, &cs);
                        if (ret) {
                                dev_err(dev, "could not retrieve reg property: %d\n",
                                        ret);
                                return ret;
                        }
                }

                if (cs >= nfc->caps->max_cs_nb) {
                        dev_err(dev, "invalid reg value: %u (max CS = %d)\n",
                                cs, nfc->caps->max_cs_nb);
                        return -EINVAL;
                }

                if (test_and_set_bit(cs, &nfc->assigned_cs)) {
                        dev_err(dev, "CS %d already assigned\n", cs);
                        return -EINVAL;
                }

                /*
                 * The cs variable represents the chip select id, which must be
                 * converted in bit fields for NDCB0 and NDCB2 to select the
                 * right chip. Unfortunately, due to a lack of information on
                 * the subject and incoherent documentation, the user should not
                 * use CS1 and CS3 at all as asserting them is not supported in
                 * a reliable way (due to multiplexing inside ADDR5 field).
                 */
                marvell_nand->sels[i].cs = cs;
                switch (cs) {
                case 0:
                case 2:
                        marvell_nand->sels[i].ndcb0_csel = 0;
                        break;
                case 1:
                case 3:
                        marvell_nand->sels[i].ndcb0_csel = NDCB0_CSEL;
                        break;
                default:
                        return -EINVAL;
                }

                /* Retrieve RB id */
                if (pdata || nfc->caps->legacy_of_bindings) {
                        /* Legacy bindings always use RB #0 */
                        rb = 0;
                } else {
                        ret = of_property_read_u32_index(np, "nand-rb", i,
                                                         &rb);
                        if (ret) {
                                dev_err(dev,
                                        "could not retrieve RB property: %d\n",
                                        ret);
                                return ret;
                        }
                }

                if (rb >= nfc->caps->max_rb_nb) {
                        dev_err(dev, "invalid reg value: %u (max RB = %d)\n",
                                rb, nfc->caps->max_rb_nb);
                        return -EINVAL;
                }

                marvell_nand->sels[i].rb = rb;
        }

        chip = &marvell_nand->chip;
        chip->controller = &nfc->controller;
        nand_set_flash_node(chip, np);

        if (!of_property_read_bool(np, "marvell,nand-keep-config"))
                chip->options |= NAND_KEEP_TIMINGS;

        mtd = nand_to_mtd(chip);
        mtd->dev.parent = dev;

        /*
         * Save a reference value for timing registers before
         * ->setup_interface() is called.
         */
        marvell_nand->ndtr0 = readl_relaxed(nfc->regs + NDTR0);
        marvell_nand->ndtr1 = readl_relaxed(nfc->regs + NDTR1);

        chip->options |= NAND_BUSWIDTH_AUTO;

        ret = nand_scan(chip, marvell_nand->nsels);
        if (ret) {
                dev_err(dev, "could not scan the nand chip\n");
                return ret;
        }

        if (pdata)
                /* Legacy bindings support only one chip */
                ret = mtd_device_register(mtd, pdata->parts, pdata->nr_parts);
        else
                ret = mtd_device_register(mtd, NULL, 0);
        if (ret) {
                dev_err(dev, "failed to register mtd device: %d\n", ret);
                nand_cleanup(chip);
                return ret;
        }

        list_add_tail(&marvell_nand->node, &nfc->chips);

        return 0;
}

static void marvell_nand_chips_cleanup(struct marvell_nfc *nfc)
{
        struct marvell_nand_chip *entry, *temp;
        struct nand_chip *chip;
        int ret;

        list_for_each_entry_safe(entry, temp, &nfc->chips, node) {
                chip = &entry->chip;
                ret = mtd_device_unregister(nand_to_mtd(chip));
                WARN_ON(ret);
                nand_cleanup(chip);
                list_del(&entry->node);
        }
}

static int marvell_nand_chips_init(struct device *dev, struct marvell_nfc *nfc)
{
        struct device_node *np = dev->of_node;
        struct device_node *nand_np;
        int max_cs = nfc->caps->max_cs_nb;
        int nchips;
        int ret;

        if (!np)
                nchips = 1;
        else
                nchips = of_get_child_count(np);

        if (nchips > max_cs) {
                dev_err(dev, "too many NAND chips: %d (max = %d CS)\n", nchips,
                        max_cs);
                return -EINVAL;
        }

        /*
         * Legacy bindings do not use child nodes to exhibit NAND chip
         * properties and layout. Instead, NAND properties are mixed with the
         * controller ones, and partitions are defined as direct subnodes of the
         * NAND controller node.
         */
        if (nfc->caps->legacy_of_bindings) {
                ret = marvell_nand_chip_init(dev, nfc, np);
                return ret;
        }

        for_each_child_of_node(np, nand_np) {
                ret = marvell_nand_chip_init(dev, nfc, nand_np);
                if (ret) {
                        of_node_put(nand_np);
                        goto cleanup_chips;
                }
        }

        return 0;

cleanup_chips:
        marvell_nand_chips_cleanup(nfc);

        return ret;
}

static int marvell_nfc_init_dma(struct marvell_nfc *nfc)
{
        struct platform_device *pdev = container_of(nfc->dev,
                                                    struct platform_device,
                                                    dev);
        struct dma_slave_config config = {};
        struct resource *r;
        int ret;

        if (!IS_ENABLED(CONFIG_PXA_DMA)) {
                dev_warn(nfc->dev,
                         "DMA not enabled in configuration\n");
                return -ENOTSUPP;
        }

        ret = dma_set_mask_and_coherent(nfc->dev, DMA_BIT_MASK(32));
        if (ret)
                return ret;

        nfc->dma_chan = dma_request_chan(nfc->dev, "data");
        if (IS_ERR(nfc->dma_chan)) {
                ret = PTR_ERR(nfc->dma_chan);
                nfc->dma_chan = NULL;
                return dev_err_probe(nfc->dev, ret, "DMA channel request failed\n");
        }

        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!r) {
                ret = -ENXIO;
                goto release_channel;
        }

        config.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
        config.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
        config.src_addr = r->start + NDDB;
        config.dst_addr = r->start + NDDB;
        config.src_maxburst = 32;
        config.dst_maxburst = 32;
        ret = dmaengine_slave_config(nfc->dma_chan, &config);
        if (ret < 0) {
                dev_err(nfc->dev, "Failed to configure DMA channel\n");
                goto release_channel;
        }

        /*
         * DMA must act on length multiple of 32 and this length may be
         * bigger than the destination buffer. Use this buffer instead
         * for DMA transfers and then copy the desired amount of data to
         * the provided buffer.
         */
        nfc->dma_buf = kmalloc(MAX_CHUNK_SIZE, GFP_KERNEL | GFP_DMA);
        if (!nfc->dma_buf) {
                ret = -ENOMEM;
                goto release_channel;
        }

        nfc->use_dma = true;

        return 0;

release_channel:
        dma_release_channel(nfc->dma_chan);
        nfc->dma_chan = NULL;

        return ret;
}

static void marvell_nfc_reset(struct marvell_nfc *nfc)
{
        /*
         * ECC operations and interruptions are only enabled when specifically
         * needed. ECC shall not be activated in the early stages (fails probe).
         * Arbiter flag, even if marked as "reserved", must be set (empirical).
         * SPARE_EN bit must always be set or ECC bytes will not be at the same
         * offset in the read page and this will fail the protection.
         */
        writel_relaxed(NDCR_ALL_INT | NDCR_ND_ARB_EN | NDCR_SPARE_EN |
                       NDCR_RD_ID_CNT(NFCV1_READID_LEN), nfc->regs + NDCR);
        writel_relaxed(0xFFFFFFFF, nfc->regs + NDSR);
        writel_relaxed(0, nfc->regs + NDECCCTRL);
}

static int marvell_nfc_init(struct marvell_nfc *nfc)
{
        struct device_node *np = nfc->dev->of_node;

        /*
         * Some SoCs like A7k/A8k need to enable manually the NAND
         * controller, gated clocks and reset bits to avoid being bootloader
         * dependent. This is done through the use of the System Functions
         * registers.
         */
        if (nfc->caps->need_system_controller) {
                struct regmap *sysctrl_base =
                        syscon_regmap_lookup_by_phandle(np,
                                                        "marvell,system-controller");

                if (IS_ERR(sysctrl_base))
                        return PTR_ERR(sysctrl_base);

                regmap_write(sysctrl_base, GENCONF_SOC_DEVICE_MUX,
                             GENCONF_SOC_DEVICE_MUX_NFC_EN |
                             GENCONF_SOC_DEVICE_MUX_ECC_CLK_RST |
                             GENCONF_SOC_DEVICE_MUX_ECC_CORE_RST |
                             GENCONF_SOC_DEVICE_MUX_NFC_INT_EN);

                regmap_update_bits(sysctrl_base, GENCONF_CLK_GATING_CTRL,
                                   GENCONF_CLK_GATING_CTRL_ND_GATE,
                                   GENCONF_CLK_GATING_CTRL_ND_GATE);

                regmap_update_bits(sysctrl_base, GENCONF_ND_CLK_CTRL,
                                   GENCONF_ND_CLK_CTRL_EN,
                                   GENCONF_ND_CLK_CTRL_EN);
        }

        /* Configure the DMA if appropriate */
        if (!nfc->caps->is_nfcv2)
                marvell_nfc_init_dma(nfc);

        marvell_nfc_reset(nfc);

        return 0;
}

static int marvell_nfc_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct marvell_nfc *nfc;
        int ret;
        int irq;

        nfc = devm_kzalloc(&pdev->dev, sizeof(struct marvell_nfc),
                           GFP_KERNEL);
        if (!nfc)
                return -ENOMEM;

        nfc->dev = dev;
        nand_controller_init(&nfc->controller);
        nfc->controller.ops = &marvell_nand_controller_ops;
        INIT_LIST_HEAD(&nfc->chips);

        nfc->regs = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(nfc->regs))
                return PTR_ERR(nfc->regs);

        irq = platform_get_irq(pdev, 0);
        if (irq < 0)
                return irq;

        nfc->core_clk = devm_clk_get(&pdev->dev, "core");

        /* Managed the legacy case (when the first clock was not named) */
        if (nfc->core_clk == ERR_PTR(-ENOENT))
                nfc->core_clk = devm_clk_get(&pdev->dev, NULL);

        if (IS_ERR(nfc->core_clk))
                return PTR_ERR(nfc->core_clk);

        ret = clk_prepare_enable(nfc->core_clk);
        if (ret)
                return ret;

        nfc->reg_clk = devm_clk_get(&pdev->dev, "reg");
        if (IS_ERR(nfc->reg_clk)) {
                if (PTR_ERR(nfc->reg_clk) != -ENOENT) {
                        ret = PTR_ERR(nfc->reg_clk);
                        goto unprepare_core_clk;
                }

                nfc->reg_clk = NULL;
        }

        ret = clk_prepare_enable(nfc->reg_clk);
        if (ret)
                goto unprepare_core_clk;

        marvell_nfc_disable_int(nfc, NDCR_ALL_INT);
        marvell_nfc_clear_int(nfc, NDCR_ALL_INT);
        ret = devm_request_irq(dev, irq, marvell_nfc_isr,
                               0, "marvell-nfc", nfc);
        if (ret)
                goto unprepare_reg_clk;

        /* Get NAND controller capabilities */
        if (pdev->id_entry)
                nfc->caps = (void *)pdev->id_entry->driver_data;
        else
                nfc->caps = of_device_get_match_data(&pdev->dev);

        if (!nfc->caps) {
                dev_err(dev, "Could not retrieve NFC caps\n");
                ret = -EINVAL;
                goto unprepare_reg_clk;
        }

        /* Init the controller and then probe the chips */
        ret = marvell_nfc_init(nfc);
        if (ret)
                goto unprepare_reg_clk;

        platform_set_drvdata(pdev, nfc);

        ret = marvell_nand_chips_init(dev, nfc);
        if (ret)
                goto release_dma;

        return 0;

release_dma:
        if (nfc->use_dma)
                dma_release_channel(nfc->dma_chan);
unprepare_reg_clk:
        clk_disable_unprepare(nfc->reg_clk);
unprepare_core_clk:
        clk_disable_unprepare(nfc->core_clk);

        return ret;
}

static int marvell_nfc_remove(struct platform_device *pdev)
{
        struct marvell_nfc *nfc = platform_get_drvdata(pdev);

        marvell_nand_chips_cleanup(nfc);

        if (nfc->use_dma) {
                dmaengine_terminate_all(nfc->dma_chan);
                dma_release_channel(nfc->dma_chan);
        }

        clk_disable_unprepare(nfc->reg_clk);
        clk_disable_unprepare(nfc->core_clk);

        return 0;
}

static int __maybe_unused marvell_nfc_suspend(struct device *dev)
{
        struct marvell_nfc *nfc = dev_get_drvdata(dev);
        struct marvell_nand_chip *chip;

        list_for_each_entry(chip, &nfc->chips, node)
                marvell_nfc_wait_ndrun(&chip->chip);

        clk_disable_unprepare(nfc->reg_clk);
        clk_disable_unprepare(nfc->core_clk);

        return 0;
}

static int __maybe_unused marvell_nfc_resume(struct device *dev)
{
        struct marvell_nfc *nfc = dev_get_drvdata(dev);
        int ret;

        ret = clk_prepare_enable(nfc->core_clk);
        if (ret < 0)
                return ret;

        ret = clk_prepare_enable(nfc->reg_clk);
        if (ret < 0)
                return ret;

        /*
         * Reset nfc->selected_chip so the next command will cause the timing
         * registers to be restored in marvell_nfc_select_target().
         */
        nfc->selected_chip = NULL;

        /* Reset registers that have lost their contents */
        marvell_nfc_reset(nfc);

        return 0;
}

static const struct dev_pm_ops marvell_nfc_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(marvell_nfc_suspend, marvell_nfc_resume)
};

static const struct marvell_nfc_caps marvell_armada_8k_nfc_caps = {
        .max_cs_nb = 4,
        .max_rb_nb = 2,
        .need_system_controller = true,
        .is_nfcv2 = true,
};

static const struct marvell_nfc_caps marvell_armada370_nfc_caps = {
        .max_cs_nb = 4,
        .max_rb_nb = 2,
        .is_nfcv2 = true,
};

static const struct marvell_nfc_caps marvell_pxa3xx_nfc_caps = {
        .max_cs_nb = 2,
        .max_rb_nb = 1,
        .use_dma = true,
};

static const struct marvell_nfc_caps marvell_armada_8k_nfc_legacy_caps = {
        .max_cs_nb = 4,
        .max_rb_nb = 2,
        .need_system_controller = true,
        .legacy_of_bindings = true,
        .is_nfcv2 = true,
};

static const struct marvell_nfc_caps marvell_armada370_nfc_legacy_caps = {
        .max_cs_nb = 4,
        .max_rb_nb = 2,
        .legacy_of_bindings = true,
        .is_nfcv2 = true,
};

static const struct marvell_nfc_caps marvell_pxa3xx_nfc_legacy_caps = {
        .max_cs_nb = 2,
        .max_rb_nb = 1,
        .legacy_of_bindings = true,
        .use_dma = true,
};

static const struct platform_device_id marvell_nfc_platform_ids[] = {
        {
                .name = "pxa3xx-nand",
                .driver_data = (kernel_ulong_t)&marvell_pxa3xx_nfc_legacy_caps,
        },
        { /* sentinel */ },
};
MODULE_DEVICE_TABLE(platform, marvell_nfc_platform_ids);

static const struct of_device_id marvell_nfc_of_ids[] = {
        {
                .compatible = "marvell,armada-8k-nand-controller",
                .data = &marvell_armada_8k_nfc_caps,
        },
        {
                .compatible = "marvell,armada370-nand-controller",
                .data = &marvell_armada370_nfc_caps,
        },
        {
                .compatible = "marvell,pxa3xx-nand-controller",
                .data = &marvell_pxa3xx_nfc_caps,
        },
        /* Support for old/deprecated bindings: */
        {
                .compatible = "marvell,armada-8k-nand",
                .data = &marvell_armada_8k_nfc_legacy_caps,
        },
        {
                .compatible = "marvell,armada370-nand",
                .data = &marvell_armada370_nfc_legacy_caps,
        },
        {
                .compatible = "marvell,pxa3xx-nand",
                .data = &marvell_pxa3xx_nfc_legacy_caps,
        },
        { /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, marvell_nfc_of_ids);

static struct platform_driver marvell_nfc_driver = {
        .driver = {
                .name           = "marvell-nfc",
                .of_match_table = marvell_nfc_of_ids,
                .pm             = &marvell_nfc_pm_ops,
        },
        .id_table = marvell_nfc_platform_ids,
        .probe = marvell_nfc_probe,
        .remove = marvell_nfc_remove,
};
module_platform_driver(marvell_nfc_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Marvell NAND controller driver");