// SPDX-License-Identifier: GPL-2.0
/*
 * Arasan NAND Flash Controller Driver
 *
 * Copyright (C) 2014 - 2020 Xilinx, Inc.
 * Author:
 *   Miquel Raynal <miquel.raynal@bootlin.com>
 * Original work (fully rewritten):
 *   Punnaiah Choudary Kalluri <punnaia@xilinx.com>
 *   Naga Sureshkumar Relli <nagasure@xilinx.com>
 */

#include <linux/bch.h>
#include <linux/bitfield.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <linux/mtd/rawnand.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#define PKT_REG                         0x00
#define   PKT_SIZE(x)                   FIELD_PREP(GENMASK(10, 0), (x))
#define   PKT_STEPS(x)                  FIELD_PREP(GENMASK(23, 12), (x))

#define MEM_ADDR1_REG                   0x04

#define MEM_ADDR2_REG                   0x08
#define   ADDR2_STRENGTH(x)             FIELD_PREP(GENMASK(27, 25), (x))
#define   ADDR2_CS(x)                   FIELD_PREP(GENMASK(31, 30), (x))

#define CMD_REG                         0x0C
#define   CMD_1(x)                      FIELD_PREP(GENMASK(7, 0), (x))
#define   CMD_2(x)                      FIELD_PREP(GENMASK(15, 8), (x))
#define   CMD_PAGE_SIZE(x)              FIELD_PREP(GENMASK(25, 23), (x))
#define   CMD_DMA_ENABLE                BIT(27)
#define   CMD_NADDRS(x)                 FIELD_PREP(GENMASK(30, 28), (x))
#define   CMD_ECC_ENABLE                BIT(31)

#define PROG_REG                        0x10
#define   PROG_PGRD                     BIT(0)
#define   PROG_ERASE                    BIT(2)
#define   PROG_STATUS                   BIT(3)
#define   PROG_PGPROG                   BIT(4)
#define   PROG_RDID                     BIT(6)
#define   PROG_RDPARAM                  BIT(7)
#define   PROG_RST                      BIT(8)
#define   PROG_GET_FEATURE              BIT(9)
#define   PROG_SET_FEATURE              BIT(10)
#define   PROG_CHG_RD_COL_ENH           BIT(14)

#define INTR_STS_EN_REG                 0x14
#define INTR_SIG_EN_REG                 0x18
#define INTR_STS_REG                    0x1C
#define   WRITE_READY                   BIT(0)
#define   READ_READY                    BIT(1)
#define   XFER_COMPLETE                 BIT(2)
#define   DMA_BOUNDARY                  BIT(6)
#define   EVENT_MASK                    GENMASK(7, 0)

#define READY_STS_REG                   0x20

#define DMA_ADDR0_REG                   0x50
#define DMA_ADDR1_REG                   0x24

#define FLASH_STS_REG                   0x28

#define DATA_PORT_REG                   0x30

#define ECC_CONF_REG                    0x34
#define   ECC_CONF_COL(x)               FIELD_PREP(GENMASK(15, 0), (x))
#define   ECC_CONF_LEN(x)               FIELD_PREP(GENMASK(26, 16), (x))
#define   ECC_CONF_BCH_EN               BIT(27)

#define ECC_ERR_CNT_REG                 0x38
#define   GET_PKT_ERR_CNT(x)            FIELD_GET(GENMASK(7, 0), (x))
#define   GET_PAGE_ERR_CNT(x)           FIELD_GET(GENMASK(16, 8), (x))

#define ECC_SP_REG                      0x3C
#define   ECC_SP_CMD1(x)                FIELD_PREP(GENMASK(7, 0), (x))
#define   ECC_SP_CMD2(x)                FIELD_PREP(GENMASK(15, 8), (x))
#define   ECC_SP_ADDRS(x)               FIELD_PREP(GENMASK(30, 28), (x))

#define ECC_1ERR_CNT_REG                0x40
#define ECC_2ERR_CNT_REG                0x44

#define DATA_INTERFACE_REG              0x6C
#define   DIFACE_SDR_MODE(x)            FIELD_PREP(GENMASK(2, 0), (x))
#define   DIFACE_DDR_MODE(x)            FIELD_PREP(GENMASK(5, 3), (x))
#define   DIFACE_SDR                    0
#define   DIFACE_NVDDR                  BIT(9)

#define ANFC_MAX_CS                     2
#define ANFC_DFLT_TIMEOUT_US            1000000
#define ANFC_MAX_CHUNK_SIZE             SZ_1M
#define ANFC_MAX_PARAM_SIZE             SZ_4K
#define ANFC_MAX_STEPS                  SZ_2K
#define ANFC_MAX_PKT_SIZE               (SZ_2K - 1)
#define ANFC_MAX_ADDR_CYC               5U
#define ANFC_RSVD_ECC_BYTES             21

#define ANFC_XLNX_SDR_DFLT_CORE_CLK     100000000
#define ANFC_XLNX_SDR_HS_CORE_CLK       80000000

/**
 * struct anfc_op - Defines how to execute an operation
 * @pkt_reg: Packet register
 * @addr1_reg: Memory address 1 register
 * @addr2_reg: Memory address 2 register
 * @cmd_reg: Command register
 * @prog_reg: Program register
 * @steps: Number of "packets" to read/write
 * @rdy_timeout_ms: Timeout for waits on Ready/Busy pin
 * @len: Data transfer length
 * @read: Data transfer direction from the controller point of view
 */
struct anfc_op {
        u32 pkt_reg;
        u32 addr1_reg;
        u32 addr2_reg;
        u32 cmd_reg;
        u32 prog_reg;
        int steps;
        unsigned int rdy_timeout_ms;
        unsigned int len;
        bool read;
        u8 *buf;
};

/**
 * struct anand - Defines the NAND chip related information
 * @node:               Used to store NAND chips into a list
 * @chip:               NAND chip information structure
 * @cs:                 Chip select line
 * @rb:                 Ready-busy line
 * @page_sz:            Register value of the page_sz field to use
 * @clk:                Expected clock frequency to use
 * @timings:            Data interface timing mode to use
 * @ecc_conf:           Hardware ECC configuration value
 * @strength:           Register value of the ECC strength
 * @raddr_cycles:       Row address cycle information
 * @caddr_cycles:       Column address cycle information
 * @ecc_bits:           Exact number of ECC bits per syndrome
 * @ecc_total:          Total number of ECC bytes
 * @errloc:             Array of errors located with soft BCH
 * @hw_ecc:             Buffer to store syndromes computed by hardware
 * @bch:                BCH structure
 */
struct anand {
        struct list_head node;
        struct nand_chip chip;
        unsigned int cs;
        unsigned int rb;
        unsigned int page_sz;
        unsigned long clk;
        u32 timings;
        u32 ecc_conf;
        u32 strength;
        u16 raddr_cycles;
        u16 caddr_cycles;
        unsigned int ecc_bits;
        unsigned int ecc_total;
        unsigned int *errloc;
        u8 *hw_ecc;
        struct bch_control *bch;
};

/**
 * struct arasan_nfc - Defines the Arasan NAND flash controller driver instance
 * @dev:                Pointer to the device structure
 * @base:               Remapped register area
 * @controller_clk:             Pointer to the system clock
 * @bus_clk:            Pointer to the flash clock
 * @controller:         Base controller structure
 * @chips:              List of all NAND chips attached to the controller
 * @assigned_cs:        Bitmask describing already assigned CS lines
 * @cur_clk:            Current clock rate
 */
struct arasan_nfc {
        struct device *dev;
        void __iomem *base;
        struct clk *controller_clk;
        struct clk *bus_clk;
        struct nand_controller controller;
        struct list_head chips;
        unsigned long assigned_cs;
        unsigned int cur_clk;
};

static struct anand *to_anand(struct nand_chip *nand)
{
        return container_of(nand, struct anand, chip);
}

static struct arasan_nfc *to_anfc(struct nand_controller *ctrl)
{
        return container_of(ctrl, struct arasan_nfc, controller);
}

static int anfc_wait_for_event(struct arasan_nfc *nfc, unsigned int event)
{
        u32 val;
        int ret;

        ret = readl_relaxed_poll_timeout(nfc->base + INTR_STS_REG, val,
                                         val & event, 0,
                                         ANFC_DFLT_TIMEOUT_US);
        if (ret) {
                dev_err(nfc->dev, "Timeout waiting for event 0x%x\n", event);
                return -ETIMEDOUT;
        }

        writel_relaxed(event, nfc->base + INTR_STS_REG);

        return 0;
}

static int anfc_wait_for_rb(struct arasan_nfc *nfc, struct nand_chip *chip,
                            unsigned int timeout_ms)
{
        struct anand *anand = to_anand(chip);
        u32 val;
        int ret;

        /* There is no R/B interrupt, we must poll a register */
        ret = readl_relaxed_poll_timeout(nfc->base + READY_STS_REG, val,
                                         val & BIT(anand->rb),
                                         1, timeout_ms * 1000);
        if (ret) {
                dev_err(nfc->dev, "Timeout waiting for R/B 0x%x\n",
                        readl_relaxed(nfc->base + READY_STS_REG));
                return -ETIMEDOUT;
        }

        return 0;
}

static void anfc_trigger_op(struct arasan_nfc *nfc, struct anfc_op *nfc_op)
{
        writel_relaxed(nfc_op->pkt_reg, nfc->base + PKT_REG);
        writel_relaxed(nfc_op->addr1_reg, nfc->base + MEM_ADDR1_REG);
        writel_relaxed(nfc_op->addr2_reg, nfc->base + MEM_ADDR2_REG);
        writel_relaxed(nfc_op->cmd_reg, nfc->base + CMD_REG);
        writel_relaxed(nfc_op->prog_reg, nfc->base + PROG_REG);
}

static int anfc_pkt_len_config(unsigned int len, unsigned int *steps,
                               unsigned int *pktsize)
{
        unsigned int nb, sz;

        for (nb = 1; nb < ANFC_MAX_STEPS; nb *= 2) {
                sz = len / nb;
                if (sz <= ANFC_MAX_PKT_SIZE)
                        break;
        }

        if (sz * nb != len)
                return -ENOTSUPP;

        if (steps)
                *steps = nb;

        if (pktsize)
                *pktsize = sz;

        return 0;
}

/*
 * When using the embedded hardware ECC engine, the controller is in charge of
 * feeding the engine with, first, the ECC residue present in the data array.
 * A typical read operation is:
 * 1/ Assert the read operation by sending the relevant command/address cycles
 *    but targeting the column of the first ECC bytes in the OOB area instead of
 *    the main data directly.
 * 2/ After having read the relevant number of ECC bytes, the controller uses
 *    the RNDOUT/RNDSTART commands which are set into the "ECC Spare Command
 *    Register" to move the pointer back at the beginning of the main data.
 * 3/ It will read the content of the main area for a given size (pktsize) and
 *    will feed the ECC engine with this buffer again.
 * 4/ The ECC engine derives the ECC bytes for the given data and compare them
 *    with the ones already received. It eventually trigger status flags and
 *    then set the "Buffer Read Ready" flag.
 * 5/ The corrected data is then available for reading from the data port
 *    register.
 *
 * The hardware BCH ECC engine is known to be inconstent in BCH mode and never
 * reports uncorrectable errors. Because of this bug, we have to use the
 * software BCH implementation in the read path.
 */
static int anfc_read_page_hw_ecc(struct nand_chip *chip, u8 *buf,
                                 int oob_required, int page)
{
        struct arasan_nfc *nfc = to_anfc(chip->controller);
        struct mtd_info *mtd = nand_to_mtd(chip);
        struct anand *anand = to_anand(chip);
        unsigned int len = mtd->writesize + (oob_required ? mtd->oobsize : 0);
        unsigned int max_bitflips = 0;
        dma_addr_t dma_addr;
        int step, ret;
        struct anfc_op nfc_op = {
                .pkt_reg =
                        PKT_SIZE(chip->ecc.size) |
                        PKT_STEPS(chip->ecc.steps),
                .addr1_reg =
                        (page & 0xFF) << (8 * (anand->caddr_cycles)) |
                        (((page >> 8) & 0xFF) << (8 * (1 + anand->caddr_cycles))),
                .addr2_reg =
                        ((page >> 16) & 0xFF) |
                        ADDR2_STRENGTH(anand->strength) |
                        ADDR2_CS(anand->cs),
                .cmd_reg =
                        CMD_1(NAND_CMD_READ0) |
                        CMD_2(NAND_CMD_READSTART) |
                        CMD_PAGE_SIZE(anand->page_sz) |
                        CMD_DMA_ENABLE |
                        CMD_NADDRS(anand->caddr_cycles +
                                   anand->raddr_cycles),
                .prog_reg = PROG_PGRD,
        };

        dma_addr = dma_map_single(nfc->dev, (void *)buf, len, DMA_FROM_DEVICE);
        if (dma_mapping_error(nfc->dev, dma_addr)) {
                dev_err(nfc->dev, "Buffer mapping error");
                return -EIO;
        }

        writel_relaxed(lower_32_bits(dma_addr), nfc->base + DMA_ADDR0_REG);
        writel_relaxed(upper_32_bits(dma_addr), nfc->base + DMA_ADDR1_REG);

        anfc_trigger_op(nfc, &nfc_op);

        ret = anfc_wait_for_event(nfc, XFER_COMPLETE);
        dma_unmap_single(nfc->dev, dma_addr, len, DMA_FROM_DEVICE);
        if (ret) {
                dev_err(nfc->dev, "Error reading page %d\n", page);
                return ret;
        }

        /* Store the raw OOB bytes as well */
        ret = nand_change_read_column_op(chip, mtd->writesize, chip->oob_poi,
                                         mtd->oobsize, 0);
        if (ret)
                return ret;

        /*
         * For each step, compute by softare the BCH syndrome over the raw data.
         * Compare the theoretical amount of errors and compare with the
         * hardware engine feedback.
         */
        for (step = 0; step < chip->ecc.steps; step++) {
                u8 *raw_buf = &buf[step * chip->ecc.size];
                unsigned int bit, byte;
                int bf, i;

                /* Extract the syndrome, it is not necessarily aligned */
                memset(anand->hw_ecc, 0, chip->ecc.bytes);
                nand_extract_bits(anand->hw_ecc, 0,
                                  &chip->oob_poi[mtd->oobsize - anand->ecc_total],
                                  anand->ecc_bits * step, anand->ecc_bits);

                bf = bch_decode(anand->bch, raw_buf, chip->ecc.size,
                                anand->hw_ecc, NULL, NULL, anand->errloc);
                if (!bf) {
                        continue;
                } else if (bf > 0) {
                        for (i = 0; i < bf; i++) {
                                /* Only correct the data, not the syndrome */
                                if (anand->errloc[i] < (chip->ecc.size * 8)) {
                                        bit = BIT(anand->errloc[i] & 7);
                                        byte = anand->errloc[i] >> 3;
                                        raw_buf[byte] ^= bit;
                                }
                        }

                        mtd->ecc_stats.corrected += bf;
                        max_bitflips = max_t(unsigned int, max_bitflips, bf);

                        continue;
                }

                bf = nand_check_erased_ecc_chunk(raw_buf, chip->ecc.size,
                                                 NULL, 0, NULL, 0,
                                                 chip->ecc.strength);
                if (bf > 0) {
                        mtd->ecc_stats.corrected += bf;
                        max_bitflips = max_t(unsigned int, max_bitflips, bf);
                        memset(raw_buf, 0xFF, chip->ecc.size);
                } else if (bf < 0) {
                        mtd->ecc_stats.failed++;
                }
        }

        return 0;
}

static int anfc_write_page_hw_ecc(struct nand_chip *chip, const u8 *buf,
                                  int oob_required, int page)
{
        struct anand *anand = to_anand(chip);
        struct arasan_nfc *nfc = to_anfc(chip->controller);
        struct mtd_info *mtd = nand_to_mtd(chip);
        unsigned int len = mtd->writesize + (oob_required ? mtd->oobsize : 0);
        dma_addr_t dma_addr;
        int ret;
        struct anfc_op nfc_op = {
                .pkt_reg =
                        PKT_SIZE(chip->ecc.size) |
                        PKT_STEPS(chip->ecc.steps),
                .addr1_reg =
                        (page & 0xFF) << (8 * (anand->caddr_cycles)) |
                        (((page >> 8) & 0xFF) << (8 * (1 + anand->caddr_cycles))),
                .addr2_reg =
                        ((page >> 16) & 0xFF) |
                        ADDR2_STRENGTH(anand->strength) |
                        ADDR2_CS(anand->cs),
                .cmd_reg =
                        CMD_1(NAND_CMD_SEQIN) |
                        CMD_2(NAND_CMD_PAGEPROG) |
                        CMD_PAGE_SIZE(anand->page_sz) |
                        CMD_DMA_ENABLE |
                        CMD_NADDRS(anand->caddr_cycles +
                                   anand->raddr_cycles) |
                        CMD_ECC_ENABLE,
                .prog_reg = PROG_PGPROG,
        };

        writel_relaxed(anand->ecc_conf, nfc->base + ECC_CONF_REG);
        writel_relaxed(ECC_SP_CMD1(NAND_CMD_RNDIN) |
                       ECC_SP_ADDRS(anand->caddr_cycles),
                       nfc->base + ECC_SP_REG);

        dma_addr = dma_map_single(nfc->dev, (void *)buf, len, DMA_TO_DEVICE);
        if (dma_mapping_error(nfc->dev, dma_addr)) {
                dev_err(nfc->dev, "Buffer mapping error");
                return -EIO;
        }

        writel_relaxed(lower_32_bits(dma_addr), nfc->base + DMA_ADDR0_REG);
        writel_relaxed(upper_32_bits(dma_addr), nfc->base + DMA_ADDR1_REG);

        anfc_trigger_op(nfc, &nfc_op);
        ret = anfc_wait_for_event(nfc, XFER_COMPLETE);
        dma_unmap_single(nfc->dev, dma_addr, len, DMA_TO_DEVICE);
        if (ret) {
                dev_err(nfc->dev, "Error writing page %d\n", page);
                return ret;
        }

        /* Spare data is not protected */
        if (oob_required)
                ret = nand_write_oob_std(chip, page);

        return ret;
}

/* NAND framework ->exec_op() hooks and related helpers */
static int anfc_parse_instructions(struct nand_chip *chip,
                                   const struct nand_subop *subop,
                                   struct anfc_op *nfc_op)
{
        struct anand *anand = to_anand(chip);
        const struct nand_op_instr *instr = NULL;
        bool first_cmd = true;
        unsigned int op_id;
        int ret, i;

        memset(nfc_op, 0, sizeof(*nfc_op));
        nfc_op->addr2_reg = ADDR2_CS(anand->cs);
        nfc_op->cmd_reg = CMD_PAGE_SIZE(anand->page_sz);

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

                instr = &subop->instrs[op_id];

                switch (instr->type) {
                case NAND_OP_CMD_INSTR:
                        if (first_cmd)
                                nfc_op->cmd_reg |= CMD_1(instr->ctx.cmd.opcode);
                        else
                                nfc_op->cmd_reg |= CMD_2(instr->ctx.cmd.opcode);

                        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->cmd_reg |= CMD_NADDRS(naddrs);

                        for (i = 0; i < min(ANFC_MAX_ADDR_CYC, naddrs); i++) {
                                if (i < 4)
                                        nfc_op->addr1_reg |= (u32)addrs[i] << i * 8;
                                else
                                        nfc_op->addr2_reg |= addrs[i];
                        }

                        break;
                case NAND_OP_DATA_IN_INSTR:
                        nfc_op->read = true;
                        fallthrough;
                case NAND_OP_DATA_OUT_INSTR:
                        offset = nand_subop_get_data_start_off(subop, op_id);
                        buf = instr->ctx.data.buf.in;
                        nfc_op->buf = &buf[offset];
                        nfc_op->len = nand_subop_get_data_len(subop, op_id);
                        ret = anfc_pkt_len_config(nfc_op->len, &nfc_op->steps,
                                                  &pktsize);
                        if (ret)
                                return ret;

                        /*
                         * Number of DATA cycles must be aligned on 4, this
                         * means the controller might read/write more than
                         * requested. This is harmless most of the time as extra
                         * DATA are discarded in the write path and read pointer
                         * adjusted in the read path.
                         *
                         * FIXME: The core should mark operations where
                         * reading/writing more is allowed so the exec_op()
                         * implementation can take the right decision when the
                         * alignment constraint is not met: adjust the number of
                         * DATA cycles when it's allowed, reject the operation
                         * otherwise.
                         */
                        nfc_op->pkt_reg |= PKT_SIZE(round_up(pktsize, 4)) |
                                           PKT_STEPS(nfc_op->steps);
                        break;
                case NAND_OP_WAITRDY_INSTR:
                        nfc_op->rdy_timeout_ms = instr->ctx.waitrdy.timeout_ms;
                        break;
                }
        }

        return 0;
}

static int anfc_rw_pio_op(struct arasan_nfc *nfc, struct anfc_op *nfc_op)
{
        unsigned int dwords = (nfc_op->len / 4) / nfc_op->steps;
        unsigned int last_len = nfc_op->len % 4;
        unsigned int offset, dir;
        u8 *buf = nfc_op->buf;
        int ret, i;

        for (i = 0; i < nfc_op->steps; i++) {
                dir = nfc_op->read ? READ_READY : WRITE_READY;
                ret = anfc_wait_for_event(nfc, dir);
                if (ret) {
                        dev_err(nfc->dev, "PIO %s ready signal not received\n",
                                nfc_op->read ? "Read" : "Write");
                        return ret;
                }

                offset = i * (dwords * 4);
                if (nfc_op->read)
                        ioread32_rep(nfc->base + DATA_PORT_REG, &buf[offset],
                                     dwords);
                else
                        iowrite32_rep(nfc->base + DATA_PORT_REG, &buf[offset],
                                      dwords);
        }

        if (last_len) {
                u32 remainder;

                offset = nfc_op->len - last_len;

                if (nfc_op->read) {
                        remainder = readl_relaxed(nfc->base + DATA_PORT_REG);
                        memcpy(&buf[offset], &remainder, last_len);
                } else {
                        memcpy(&remainder, &buf[offset], last_len);
                        writel_relaxed(remainder, nfc->base + DATA_PORT_REG);
                }
        }

        return anfc_wait_for_event(nfc, XFER_COMPLETE);
}

static int anfc_misc_data_type_exec(struct nand_chip *chip,
                                    const struct nand_subop *subop,
                                    u32 prog_reg)
{
        struct arasan_nfc *nfc = to_anfc(chip->controller);
        struct anfc_op nfc_op = {};
        int ret;

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

        nfc_op.prog_reg = prog_reg;
        anfc_trigger_op(nfc, &nfc_op);

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

        return anfc_rw_pio_op(nfc, &nfc_op);
}

static int anfc_param_read_type_exec(struct nand_chip *chip,
                                     const struct nand_subop *subop)
{
        return anfc_misc_data_type_exec(chip, subop, PROG_RDPARAM);
}

static int anfc_data_read_type_exec(struct nand_chip *chip,
                                    const struct nand_subop *subop)
{
        u32 prog_reg = PROG_PGRD;

        /*
         * Experience shows that while in SDR mode sending a CHANGE READ COLUMN
         * command through the READ PAGE "type" always works fine, when in
         * NV-DDR mode the same command simply fails. However, it was also
         * spotted that any CHANGE READ COLUMN command sent through the CHANGE
         * READ COLUMN ENHANCED "type" would correctly work in both cases (SDR
         * and NV-DDR). So, for simplicity, let's program the controller with
         * the CHANGE READ COLUMN ENHANCED "type" whenever we are requested to
         * perform a CHANGE READ COLUMN operation.
         */
        if (subop->instrs[0].ctx.cmd.opcode == NAND_CMD_RNDOUT &&
            subop->instrs[2].ctx.cmd.opcode == NAND_CMD_RNDOUTSTART)
                prog_reg = PROG_CHG_RD_COL_ENH;

        return anfc_misc_data_type_exec(chip, subop, prog_reg);
}

static int anfc_param_write_type_exec(struct nand_chip *chip,
                                      const struct nand_subop *subop)
{
        return anfc_misc_data_type_exec(chip, subop, PROG_SET_FEATURE);
}

static int anfc_data_write_type_exec(struct nand_chip *chip,
                                     const struct nand_subop *subop)
{
        return anfc_misc_data_type_exec(chip, subop, PROG_PGPROG);
}

static int anfc_misc_zerolen_type_exec(struct nand_chip *chip,
                                       const struct nand_subop *subop,
                                       u32 prog_reg)
{
        struct arasan_nfc *nfc = to_anfc(chip->controller);
        struct anfc_op nfc_op = {};
        int ret;

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

        nfc_op.prog_reg = prog_reg;
        anfc_trigger_op(nfc, &nfc_op);

        ret = anfc_wait_for_event(nfc, XFER_COMPLETE);
        if (ret)
                return ret;

        if (nfc_op.rdy_timeout_ms)
                ret = anfc_wait_for_rb(nfc, chip, nfc_op.rdy_timeout_ms);

        return ret;
}

static int anfc_status_type_exec(struct nand_chip *chip,
                                 const struct nand_subop *subop)
{
        struct arasan_nfc *nfc = to_anfc(chip->controller);
        u32 tmp;
        int ret;

        /* See anfc_check_op() for details about this constraint */
        if (subop->instrs[0].ctx.cmd.opcode != NAND_CMD_STATUS)
                return -ENOTSUPP;

        ret = anfc_misc_zerolen_type_exec(chip, subop, PROG_STATUS);
        if (ret)
                return ret;

        tmp = readl_relaxed(nfc->base + FLASH_STS_REG);
        memcpy(subop->instrs[1].ctx.data.buf.in, &tmp, 1);

        return 0;
}

static int anfc_reset_type_exec(struct nand_chip *chip,
                                const struct nand_subop *subop)
{
        return anfc_misc_zerolen_type_exec(chip, subop, PROG_RST);
}

static int anfc_erase_type_exec(struct nand_chip *chip,
                                const struct nand_subop *subop)
{
        return anfc_misc_zerolen_type_exec(chip, subop, PROG_ERASE);
}

static int anfc_wait_type_exec(struct nand_chip *chip,
                               const struct nand_subop *subop)
{
        struct arasan_nfc *nfc = to_anfc(chip->controller);
        struct anfc_op nfc_op = {};
        int ret;

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

        return anfc_wait_for_rb(nfc, chip, nfc_op.rdy_timeout_ms);
}

static const struct nand_op_parser anfc_op_parser = NAND_OP_PARSER(
        NAND_OP_PARSER_PATTERN(
                anfc_param_read_type_exec,
                NAND_OP_PARSER_PAT_CMD_ELEM(false),
                NAND_OP_PARSER_PAT_ADDR_ELEM(false, ANFC_MAX_ADDR_CYC),
                NAND_OP_PARSER_PAT_WAITRDY_ELEM(true),
                NAND_OP_PARSER_PAT_DATA_IN_ELEM(false, ANFC_MAX_CHUNK_SIZE)),
        NAND_OP_PARSER_PATTERN(
                anfc_param_write_type_exec,
                NAND_OP_PARSER_PAT_CMD_ELEM(false),
                NAND_OP_PARSER_PAT_ADDR_ELEM(false, ANFC_MAX_ADDR_CYC),
                NAND_OP_PARSER_PAT_DATA_OUT_ELEM(false, ANFC_MAX_PARAM_SIZE)),
        NAND_OP_PARSER_PATTERN(
                anfc_data_read_type_exec,
                NAND_OP_PARSER_PAT_CMD_ELEM(false),
                NAND_OP_PARSER_PAT_ADDR_ELEM(false, ANFC_MAX_ADDR_CYC),
                NAND_OP_PARSER_PAT_CMD_ELEM(false),
                NAND_OP_PARSER_PAT_WAITRDY_ELEM(true),
                NAND_OP_PARSER_PAT_DATA_IN_ELEM(true, ANFC_MAX_CHUNK_SIZE)),
        NAND_OP_PARSER_PATTERN(
                anfc_data_write_type_exec,
                NAND_OP_PARSER_PAT_CMD_ELEM(false),
                NAND_OP_PARSER_PAT_ADDR_ELEM(false, ANFC_MAX_ADDR_CYC),
                NAND_OP_PARSER_PAT_DATA_OUT_ELEM(false, ANFC_MAX_CHUNK_SIZE),
                NAND_OP_PARSER_PAT_CMD_ELEM(false)),
        NAND_OP_PARSER_PATTERN(
                anfc_reset_type_exec,
                NAND_OP_PARSER_PAT_CMD_ELEM(false),
                NAND_OP_PARSER_PAT_WAITRDY_ELEM(false)),
        NAND_OP_PARSER_PATTERN(
                anfc_erase_type_exec,
                NAND_OP_PARSER_PAT_CMD_ELEM(false),
                NAND_OP_PARSER_PAT_ADDR_ELEM(false, ANFC_MAX_ADDR_CYC),
                NAND_OP_PARSER_PAT_CMD_ELEM(false),
                NAND_OP_PARSER_PAT_WAITRDY_ELEM(false)),
        NAND_OP_PARSER_PATTERN(
                anfc_status_type_exec,
                NAND_OP_PARSER_PAT_CMD_ELEM(false),
                NAND_OP_PARSER_PAT_DATA_IN_ELEM(false, ANFC_MAX_CHUNK_SIZE)),
        NAND_OP_PARSER_PATTERN(
                anfc_wait_type_exec,
                NAND_OP_PARSER_PAT_WAITRDY_ELEM(false)),
        );

static int anfc_select_target(struct nand_chip *chip, int target)
{
        struct anand *anand = to_anand(chip);
        struct arasan_nfc *nfc = to_anfc(chip->controller);
        int ret;

        /* Update the controller timings and the potential ECC configuration */
        writel_relaxed(anand->timings, nfc->base + DATA_INTERFACE_REG);

        /* Update clock frequency */
        if (nfc->cur_clk != anand->clk) {
                clk_disable_unprepare(nfc->controller_clk);
                ret = clk_set_rate(nfc->controller_clk, anand->clk);
                if (ret) {
                        dev_err(nfc->dev, "Failed to change clock rate\n");
                        return ret;
                }

                ret = clk_prepare_enable(nfc->controller_clk);
                if (ret) {
                        dev_err(nfc->dev,
                                "Failed to re-enable the controller clock\n");
                        return ret;
                }

                nfc->cur_clk = anand->clk;
        }

        return 0;
}

static int anfc_check_op(struct nand_chip *chip,
                         const struct nand_operation *op)
{
        const struct nand_op_instr *instr;
        int op_id;

        /*
         * The controller abstracts all the NAND operations and do not support
         * data only operations.
         *
         * TODO: The nand_op_parser framework should be extended to
         * support custom checks on DATA instructions.
         */
        for (op_id = 0; op_id < op->ninstrs; op_id++) {
                instr = &op->instrs[op_id];

                switch (instr->type) {
                case NAND_OP_ADDR_INSTR:
                        if (instr->ctx.addr.naddrs > ANFC_MAX_ADDR_CYC)
                                return -ENOTSUPP;

                        break;
                case NAND_OP_DATA_IN_INSTR:
                case NAND_OP_DATA_OUT_INSTR:
                        if (instr->ctx.data.len > ANFC_MAX_CHUNK_SIZE)
                                return -ENOTSUPP;

                        if (anfc_pkt_len_config(instr->ctx.data.len, 0, 0))
                                return -ENOTSUPP;

                        break;
                default:
                        break;
                }
        }

        /*
         * The controller does not allow to proceed with a CMD+DATA_IN cycle
         * manually on the bus by reading data from the data register. Instead,
         * the controller abstract a status read operation with its own status
         * register after ordering a read status operation. Hence, we cannot
         * support any CMD+DATA_IN operation other than a READ STATUS.
         *
         * TODO: The nand_op_parser() framework should be extended to describe
         * fixed patterns instead of open-coding this check here.
         */
        if (op->ninstrs == 2 &&
            op->instrs[0].type == NAND_OP_CMD_INSTR &&
            op->instrs[0].ctx.cmd.opcode != NAND_CMD_STATUS &&
            op->instrs[1].type == NAND_OP_DATA_IN_INSTR)
                return -ENOTSUPP;

        return nand_op_parser_exec_op(chip, &anfc_op_parser, op, true);
}

static int anfc_exec_op(struct nand_chip *chip,
                        const struct nand_operation *op,
                        bool check_only)
{
        int ret;

        if (check_only)
                return anfc_check_op(chip, op);

        ret = anfc_select_target(chip, op->cs);
        if (ret)
                return ret;

        return nand_op_parser_exec_op(chip, &anfc_op_parser, op, check_only);
}

static int anfc_setup_interface(struct nand_chip *chip, int target,
                                const struct nand_interface_config *conf)
{
        struct anand *anand = to_anand(chip);
        struct arasan_nfc *nfc = to_anfc(chip->controller);
        struct device_node *np = nfc->dev->of_node;
        const struct nand_sdr_timings *sdr;
        const struct nand_nvddr_timings *nvddr;

        if (nand_interface_is_nvddr(conf)) {
                nvddr = nand_get_nvddr_timings(conf);
                if (IS_ERR(nvddr))
                        return PTR_ERR(nvddr);
        } else {
                sdr = nand_get_sdr_timings(conf);
                if (IS_ERR(sdr))
                        return PTR_ERR(sdr);
        }

        if (target < 0)
                return 0;

        if (nand_interface_is_sdr(conf))
                anand->timings = DIFACE_SDR |
                                 DIFACE_SDR_MODE(conf->timings.mode);
        else
                anand->timings = DIFACE_NVDDR |
                                 DIFACE_DDR_MODE(conf->timings.mode);

        anand->clk = ANFC_XLNX_SDR_DFLT_CORE_CLK;

        /*
         * Due to a hardware bug in the ZynqMP SoC, SDR timing modes 0-1 work
         * with f > 90MHz (default clock is 100MHz) but signals are unstable
         * with higher modes. Hence we decrease a little bit the clock rate to
         * 80MHz when using SDR modes 2-5 with this SoC.
         */
        if (of_device_is_compatible(np, "xlnx,zynqmp-nand-controller") &&
            nand_interface_is_sdr(conf) && conf->timings.mode >= 2)
                anand->clk = ANFC_XLNX_SDR_HS_CORE_CLK;

        return 0;
}

static int anfc_calc_hw_ecc_bytes(int step_size, int strength)
{
        unsigned int bch_gf_mag, ecc_bits;

        switch (step_size) {
        case SZ_512:
                bch_gf_mag = 13;
                break;
        case SZ_1K:
                bch_gf_mag = 14;
                break;
        default:
                return -EINVAL;
        }

        ecc_bits = bch_gf_mag * strength;

        return DIV_ROUND_UP(ecc_bits, 8);
}

static const int anfc_hw_ecc_512_strengths[] = {4, 8, 12};

static const int anfc_hw_ecc_1024_strengths[] = {24};

static const struct nand_ecc_step_info anfc_hw_ecc_step_infos[] = {
        {
                .stepsize = SZ_512,
                .strengths = anfc_hw_ecc_512_strengths,
                .nstrengths = ARRAY_SIZE(anfc_hw_ecc_512_strengths),
        },
        {
                .stepsize = SZ_1K,
                .strengths = anfc_hw_ecc_1024_strengths,
                .nstrengths = ARRAY_SIZE(anfc_hw_ecc_1024_strengths),
        },
};

static const struct nand_ecc_caps anfc_hw_ecc_caps = {
        .stepinfos = anfc_hw_ecc_step_infos,
        .nstepinfos = ARRAY_SIZE(anfc_hw_ecc_step_infos),
        .calc_ecc_bytes = anfc_calc_hw_ecc_bytes,
};

static int anfc_init_hw_ecc_controller(struct arasan_nfc *nfc,
                                       struct nand_chip *chip)
{
        struct anand *anand = to_anand(chip);
        struct mtd_info *mtd = nand_to_mtd(chip);
        struct nand_ecc_ctrl *ecc = &chip->ecc;
        unsigned int bch_prim_poly = 0, bch_gf_mag = 0, ecc_offset;
        int ret;

        switch (mtd->writesize) {
        case SZ_512:
        case SZ_2K:
        case SZ_4K:
        case SZ_8K:
        case SZ_16K:
                break;
        default:
                dev_err(nfc->dev, "Unsupported page size %d\n", mtd->writesize);
                return -EINVAL;
        }

        ret = nand_ecc_choose_conf(chip, &anfc_hw_ecc_caps, mtd->oobsize);
        if (ret)
                return ret;

        switch (ecc->strength) {
        case 12:
                anand->strength = 0x1;
                break;
        case 8:
                anand->strength = 0x2;
                break;
        case 4:
                anand->strength = 0x3;
                break;
        case 24:
                anand->strength = 0x4;
                break;
        default:
                dev_err(nfc->dev, "Unsupported strength %d\n", ecc->strength);

                return -EINVAL;
        }

        switch (ecc->size) {
        case SZ_512:
                bch_gf_mag = 13;
                bch_prim_poly = 0x201b;
                break;
        case SZ_1K:
                bch_gf_mag = 14;
                bch_prim_poly = 0x4443;
                break;
        default:
                dev_err(nfc->dev, "Unsupported step size %d\n", ecc->strength);
                return -EINVAL;
        }

        mtd_set_ooblayout(mtd, nand_get_large_page_ooblayout());

        ecc->steps = mtd->writesize / ecc->size;
        ecc->algo = NAND_ECC_ALGO_BCH;
        anand->ecc_bits = bch_gf_mag * ecc->strength;
        ecc->bytes = DIV_ROUND_UP(anand->ecc_bits, 8);
        anand->ecc_total = DIV_ROUND_UP(anand->ecc_bits * ecc->steps, 8);
        ecc_offset = mtd->writesize + mtd->oobsize - anand->ecc_total;
        anand->ecc_conf = ECC_CONF_COL(ecc_offset) |
                          ECC_CONF_LEN(anand->ecc_total) |
                          ECC_CONF_BCH_EN;

        anand->errloc = devm_kmalloc_array(nfc->dev, ecc->strength,
                                           sizeof(*anand->errloc), GFP_KERNEL);
        if (!anand->errloc)
                return -ENOMEM;

        anand->hw_ecc = devm_kmalloc(nfc->dev, ecc->bytes, GFP_KERNEL);
        if (!anand->hw_ecc)
                return -ENOMEM;

        /* Enforce bit swapping to fit the hardware */
        anand->bch = bch_init(bch_gf_mag, ecc->strength, bch_prim_poly, true);
        if (!anand->bch)
                return -EINVAL;

        ecc->read_page = anfc_read_page_hw_ecc;
        ecc->write_page = anfc_write_page_hw_ecc;

        return 0;
}

static int anfc_attach_chip(struct nand_chip *chip)
{
        struct anand *anand = to_anand(chip);
        struct arasan_nfc *nfc = to_anfc(chip->controller);
        struct mtd_info *mtd = nand_to_mtd(chip);
        int ret = 0;

        if (mtd->writesize <= SZ_512)
                anand->caddr_cycles = 1;
        else
                anand->caddr_cycles = 2;

        if (chip->options & NAND_ROW_ADDR_3)
                anand->raddr_cycles = 3;
        else
                anand->raddr_cycles = 2;

        switch (mtd->writesize) {
        case 512:
                anand->page_sz = 0;
                break;
        case 1024:
                anand->page_sz = 5;
                break;
        case 2048:
                anand->page_sz = 1;
                break;
        case 4096:
                anand->page_sz = 2;
                break;
        case 8192:
                anand->page_sz = 3;
                break;
        case 16384:
                anand->page_sz = 4;
                break;
        default:
                return -EINVAL;
        }

        /* These hooks are valid for all ECC providers */
        chip->ecc.read_page_raw = nand_monolithic_read_page_raw;
        chip->ecc.write_page_raw = nand_monolithic_write_page_raw;

        switch (chip->ecc.engine_type) {
        case NAND_ECC_ENGINE_TYPE_NONE:
        case NAND_ECC_ENGINE_TYPE_SOFT:
        case NAND_ECC_ENGINE_TYPE_ON_DIE:
                break;
        case NAND_ECC_ENGINE_TYPE_ON_HOST:
                ret = anfc_init_hw_ecc_controller(nfc, chip);
                break;
        default:
                dev_err(nfc->dev, "Unsupported ECC mode: %d\n",
                        chip->ecc.engine_type);
                return -EINVAL;
        }

        return ret;
}

static void anfc_detach_chip(struct nand_chip *chip)
{
        struct anand *anand = to_anand(chip);

        if (anand->bch)
                bch_free(anand->bch);
}

static const struct nand_controller_ops anfc_ops = {
        .exec_op = anfc_exec_op,
        .setup_interface = anfc_setup_interface,
        .attach_chip = anfc_attach_chip,
        .detach_chip = anfc_detach_chip,
};

static int anfc_chip_init(struct arasan_nfc *nfc, struct device_node *np)
{
        struct anand *anand;
        struct nand_chip *chip;
        struct mtd_info *mtd;
        int cs, rb, ret;

        anand = devm_kzalloc(nfc->dev, sizeof(*anand), GFP_KERNEL);
        if (!anand)
                return -ENOMEM;

        /* We do not support multiple CS per chip yet */
        if (of_property_count_elems_of_size(np, "reg", sizeof(u32)) != 1) {
                dev_err(nfc->dev, "Invalid reg property\n");
                return -EINVAL;
        }

        ret = of_property_read_u32(np, "reg", &cs);
        if (ret)
                return ret;

        ret = of_property_read_u32(np, "nand-rb", &rb);
        if (ret)
                return ret;

        if (cs >= ANFC_MAX_CS || rb >= ANFC_MAX_CS) {
                dev_err(nfc->dev, "Wrong CS %d or RB %d\n", cs, rb);
                return -EINVAL;
        }

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

        anand->cs = cs;
        anand->rb = rb;

        chip = &anand->chip;
        mtd = nand_to_mtd(chip);
        mtd->dev.parent = nfc->dev;
        chip->controller = &nfc->controller;
        chip->options = NAND_BUSWIDTH_AUTO | NAND_NO_SUBPAGE_WRITE |
                        NAND_USES_DMA;

        nand_set_flash_node(chip, np);
        if (!mtd->name) {
                dev_err(nfc->dev, "NAND label property is mandatory\n");
                return -EINVAL;
        }

        ret = nand_scan(chip, 1);
        if (ret) {
                dev_err(nfc->dev, "Scan operation failed\n");
                return ret;
        }

        ret = mtd_device_register(mtd, NULL, 0);
        if (ret) {
                nand_cleanup(chip);
                return ret;
        }

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

        return 0;
}

static void anfc_chips_cleanup(struct arasan_nfc *nfc)
{
        struct anand *anand, *tmp;
        struct nand_chip *chip;
        int ret;

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

static int anfc_chips_init(struct arasan_nfc *nfc)
{
        struct device_node *np = nfc->dev->of_node, *nand_np;
        int nchips = of_get_child_count(np);
        int ret;

        if (!nchips || nchips > ANFC_MAX_CS) {
                dev_err(nfc->dev, "Incorrect number of NAND chips (%d)\n",
                        nchips);
                return -EINVAL;
        }

        for_each_child_of_node(np, nand_np) {
                ret = anfc_chip_init(nfc, nand_np);
                if (ret) {
                        of_node_put(nand_np);
                        anfc_chips_cleanup(nfc);
                        break;
                }
        }

        return ret;
}

static void anfc_reset(struct arasan_nfc *nfc)
{
        /* Disable interrupt signals */
        writel_relaxed(0, nfc->base + INTR_SIG_EN_REG);

        /* Enable interrupt status */
        writel_relaxed(EVENT_MASK, nfc->base + INTR_STS_EN_REG);
}

static int anfc_probe(struct platform_device *pdev)
{
        struct arasan_nfc *nfc;
        int ret;

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

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

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

        anfc_reset(nfc);

        nfc->controller_clk = devm_clk_get(&pdev->dev, "controller");
        if (IS_ERR(nfc->controller_clk))
                return PTR_ERR(nfc->controller_clk);

        nfc->bus_clk = devm_clk_get(&pdev->dev, "bus");
        if (IS_ERR(nfc->bus_clk))
                return PTR_ERR(nfc->bus_clk);

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

        ret = clk_prepare_enable(nfc->bus_clk);
        if (ret)
                goto disable_controller_clk;

        ret = anfc_chips_init(nfc);
        if (ret)
                goto disable_bus_clk;

        platform_set_drvdata(pdev, nfc);

        return 0;

disable_bus_clk:
        clk_disable_unprepare(nfc->bus_clk);

disable_controller_clk:
        clk_disable_unprepare(nfc->controller_clk);

        return ret;
}

static int anfc_remove(struct platform_device *pdev)
{
        struct arasan_nfc *nfc = platform_get_drvdata(pdev);

        anfc_chips_cleanup(nfc);

        clk_disable_unprepare(nfc->bus_clk);
        clk_disable_unprepare(nfc->controller_clk);

        return 0;
}

static const struct of_device_id anfc_ids[] = {
        {
                .compatible = "xlnx,zynqmp-nand-controller",
        },
        {
                .compatible = "arasan,nfc-v3p10",
        },
        {}
};
MODULE_DEVICE_TABLE(of, anfc_ids);

static struct platform_driver anfc_driver = {
        .driver = {
                .name = "arasan-nand-controller",
                .of_match_table = anfc_ids,
        },
        .probe = anfc_probe,
        .remove = anfc_remove,
};
module_platform_driver(anfc_driver);

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Punnaiah Choudary Kalluri <punnaia@xilinx.com>");
MODULE_AUTHOR("Naga Sureshkumar Relli <nagasure@xilinx.com>");
MODULE_AUTHOR("Miquel Raynal <miquel.raynal@bootlin.com>");
MODULE_DESCRIPTION("Arasan NAND Flash Controller Driver");