// SPDX-License-Identifier: GPL-2.0
/*
 * NAND Flash Controller Device Driver
 * Copyright © 2009-2010, Intel Corporation and its suppliers.
 *
 * Copyright (c) 2017-2019 Socionext Inc.
 *   Reworked by Masahiro Yamada <yamada.masahiro@socionext.com>
 */

#include <linux/bitfield.h>
#include <linux/completion.h>
#include <linux/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/rawnand.h>
#include <linux/slab.h>
#include <linux/spinlock.h>

#include "denali.h"

#define DENALI_NAND_NAME    "denali-nand"

/* for Indexed Addressing */
#define DENALI_INDEXED_CTRL     0x00
#define DENALI_INDEXED_DATA     0x10

#define DENALI_MAP00            (0 << 26)       /* direct access to buffer */
#define DENALI_MAP01            (1 << 26)       /* read/write pages in PIO */
#define DENALI_MAP10            (2 << 26)       /* high-level control plane */
#define DENALI_MAP11            (3 << 26)       /* direct controller access */

/* MAP11 access cycle type */
#define DENALI_MAP11_CMD        ((DENALI_MAP11) | 0)    /* command cycle */
#define DENALI_MAP11_ADDR       ((DENALI_MAP11) | 1)    /* address cycle */
#define DENALI_MAP11_DATA       ((DENALI_MAP11) | 2)    /* data cycle */

#define DENALI_BANK(denali)     ((denali)->active_bank << 24)

#define DENALI_INVALID_BANK     -1

static struct denali_chip *to_denali_chip(struct nand_chip *chip)
{
        return container_of(chip, struct denali_chip, chip);
}

static struct denali_controller *to_denali_controller(struct nand_chip *chip)
{
        return container_of(chip->controller, struct denali_controller,
                            controller);
}

/*
 * Direct Addressing - the slave address forms the control information (command
 * type, bank, block, and page address).  The slave data is the actual data to
 * be transferred.  This mode requires 28 bits of address region allocated.
 */
static u32 denali_direct_read(struct denali_controller *denali, u32 addr)
{
        return ioread32(denali->host + addr);
}

static void denali_direct_write(struct denali_controller *denali, u32 addr,
                                u32 data)
{
        iowrite32(data, denali->host + addr);
}

/*
 * Indexed Addressing - address translation module intervenes in passing the
 * control information.  This mode reduces the required address range.  The
 * control information and transferred data are latched by the registers in
 * the translation module.
 */
static u32 denali_indexed_read(struct denali_controller *denali, u32 addr)
{
        iowrite32(addr, denali->host + DENALI_INDEXED_CTRL);
        return ioread32(denali->host + DENALI_INDEXED_DATA);
}

static void denali_indexed_write(struct denali_controller *denali, u32 addr,
                                 u32 data)
{
        iowrite32(addr, denali->host + DENALI_INDEXED_CTRL);
        iowrite32(data, denali->host + DENALI_INDEXED_DATA);
}

static void denali_enable_irq(struct denali_controller *denali)
{
        int i;

        for (i = 0; i < denali->nbanks; i++)
                iowrite32(U32_MAX, denali->reg + INTR_EN(i));
        iowrite32(GLOBAL_INT_EN_FLAG, denali->reg + GLOBAL_INT_ENABLE);
}

static void denali_disable_irq(struct denali_controller *denali)
{
        int i;

        for (i = 0; i < denali->nbanks; i++)
                iowrite32(0, denali->reg + INTR_EN(i));
        iowrite32(0, denali->reg + GLOBAL_INT_ENABLE);
}

static void denali_clear_irq(struct denali_controller *denali,
                             int bank, u32 irq_status)
{
        /* write one to clear bits */
        iowrite32(irq_status, denali->reg + INTR_STATUS(bank));
}

static void denali_clear_irq_all(struct denali_controller *denali)
{
        int i;

        for (i = 0; i < denali->nbanks; i++)
                denali_clear_irq(denali, i, U32_MAX);
}

static irqreturn_t denali_isr(int irq, void *dev_id)
{
        struct denali_controller *denali = dev_id;
        irqreturn_t ret = IRQ_NONE;
        u32 irq_status;
        int i;

        spin_lock(&denali->irq_lock);

        for (i = 0; i < denali->nbanks; i++) {
                irq_status = ioread32(denali->reg + INTR_STATUS(i));
                if (irq_status)
                        ret = IRQ_HANDLED;

                denali_clear_irq(denali, i, irq_status);

                if (i != denali->active_bank)
                        continue;

                denali->irq_status |= irq_status;

                if (denali->irq_status & denali->irq_mask)
                        complete(&denali->complete);
        }

        spin_unlock(&denali->irq_lock);

        return ret;
}

static void denali_reset_irq(struct denali_controller *denali)
{
        unsigned long flags;

        spin_lock_irqsave(&denali->irq_lock, flags);
        denali->irq_status = 0;
        denali->irq_mask = 0;
        spin_unlock_irqrestore(&denali->irq_lock, flags);
}

static u32 denali_wait_for_irq(struct denali_controller *denali, u32 irq_mask)
{
        unsigned long time_left, flags;
        u32 irq_status;

        spin_lock_irqsave(&denali->irq_lock, flags);

        irq_status = denali->irq_status;

        if (irq_mask & irq_status) {
                /* return immediately if the IRQ has already happened. */
                spin_unlock_irqrestore(&denali->irq_lock, flags);
                return irq_status;
        }

        denali->irq_mask = irq_mask;
        reinit_completion(&denali->complete);
        spin_unlock_irqrestore(&denali->irq_lock, flags);

        time_left = wait_for_completion_timeout(&denali->complete,
                                                msecs_to_jiffies(1000));
        if (!time_left) {
                dev_err(denali->dev, "timeout while waiting for irq 0x%x\n",
                        irq_mask);
                return 0;
        }

        return denali->irq_status;
}

static void denali_select_target(struct nand_chip *chip, int cs)
{
        struct denali_controller *denali = to_denali_controller(chip);
        struct denali_chip_sel *sel = &to_denali_chip(chip)->sels[cs];
        struct mtd_info *mtd = nand_to_mtd(chip);

        denali->active_bank = sel->bank;

        iowrite32(1 << (chip->phys_erase_shift - chip->page_shift),
                  denali->reg + PAGES_PER_BLOCK);
        iowrite32(chip->options & NAND_BUSWIDTH_16 ? 1 : 0,
                  denali->reg + DEVICE_WIDTH);
        iowrite32(mtd->writesize, denali->reg + DEVICE_MAIN_AREA_SIZE);
        iowrite32(mtd->oobsize, denali->reg + DEVICE_SPARE_AREA_SIZE);
        iowrite32(chip->options & NAND_ROW_ADDR_3 ?
                  0 : TWO_ROW_ADDR_CYCLES__FLAG,
                  denali->reg + TWO_ROW_ADDR_CYCLES);
        iowrite32(FIELD_PREP(ECC_CORRECTION__ERASE_THRESHOLD, 1) |
                  FIELD_PREP(ECC_CORRECTION__VALUE, chip->ecc.strength),
                  denali->reg + ECC_CORRECTION);
        iowrite32(chip->ecc.size, denali->reg + CFG_DATA_BLOCK_SIZE);
        iowrite32(chip->ecc.size, denali->reg + CFG_LAST_DATA_BLOCK_SIZE);
        iowrite32(chip->ecc.steps, denali->reg + CFG_NUM_DATA_BLOCKS);

        if (chip->options & NAND_KEEP_TIMINGS)
                return;

        /* update timing registers unless NAND_KEEP_TIMINGS is set */
        iowrite32(sel->hwhr2_and_we_2_re, denali->reg + TWHR2_AND_WE_2_RE);
        iowrite32(sel->tcwaw_and_addr_2_data,
                  denali->reg + TCWAW_AND_ADDR_2_DATA);
        iowrite32(sel->re_2_we, denali->reg + RE_2_WE);
        iowrite32(sel->acc_clks, denali->reg + ACC_CLKS);
        iowrite32(sel->rdwr_en_lo_cnt, denali->reg + RDWR_EN_LO_CNT);
        iowrite32(sel->rdwr_en_hi_cnt, denali->reg + RDWR_EN_HI_CNT);
        iowrite32(sel->cs_setup_cnt, denali->reg + CS_SETUP_CNT);
        iowrite32(sel->re_2_re, denali->reg + RE_2_RE);
}

static int denali_change_column(struct nand_chip *chip, unsigned int offset,
                                void *buf, unsigned int len, bool write)
{
        if (write)
                return nand_change_write_column_op(chip, offset, buf, len,
                                                   false);
        else
                return nand_change_read_column_op(chip, offset, buf, len,
                                                  false);
}

static int denali_payload_xfer(struct nand_chip *chip, void *buf, bool write)
{
        struct denali_controller *denali = to_denali_controller(chip);
        struct mtd_info *mtd = nand_to_mtd(chip);
        struct nand_ecc_ctrl *ecc = &chip->ecc;
        int writesize = mtd->writesize;
        int oob_skip = denali->oob_skip_bytes;
        int ret, i, pos, len;

        for (i = 0; i < ecc->steps; i++) {
                pos = i * (ecc->size + ecc->bytes);
                len = ecc->size;

                if (pos >= writesize) {
                        pos += oob_skip;
                } else if (pos + len > writesize) {
                        /* This chunk overwraps the BBM area. Must be split */
                        ret = denali_change_column(chip, pos, buf,
                                                   writesize - pos, write);
                        if (ret)
                                return ret;

                        buf += writesize - pos;
                        len -= writesize - pos;
                        pos = writesize + oob_skip;
                }

                ret = denali_change_column(chip, pos, buf, len, write);
                if (ret)
                        return ret;

                buf += len;
        }

        return 0;
}

static int denali_oob_xfer(struct nand_chip *chip, void *buf, bool write)
{
        struct denali_controller *denali = to_denali_controller(chip);
        struct mtd_info *mtd = nand_to_mtd(chip);
        struct nand_ecc_ctrl *ecc = &chip->ecc;
        int writesize = mtd->writesize;
        int oobsize = mtd->oobsize;
        int oob_skip = denali->oob_skip_bytes;
        int ret, i, pos, len;

        /* BBM at the beginning of the OOB area */
        ret = denali_change_column(chip, writesize, buf, oob_skip, write);
        if (ret)
                return ret;

        buf += oob_skip;

        for (i = 0; i < ecc->steps; i++) {
                pos = ecc->size + i * (ecc->size + ecc->bytes);

                if (i == ecc->steps - 1)
                        /* The last chunk includes OOB free */
                        len = writesize + oobsize - pos - oob_skip;
                else
                        len = ecc->bytes;

                if (pos >= writesize) {
                        pos += oob_skip;
                } else if (pos + len > writesize) {
                        /* This chunk overwraps the BBM area. Must be split */
                        ret = denali_change_column(chip, pos, buf,
                                                   writesize - pos, write);
                        if (ret)
                                return ret;

                        buf += writesize - pos;
                        len -= writesize - pos;
                        pos = writesize + oob_skip;
                }

                ret = denali_change_column(chip, pos, buf, len, write);
                if (ret)
                        return ret;

                buf += len;
        }

        return 0;
}

static int denali_read_raw(struct nand_chip *chip, void *buf, void *oob_buf,
                           int page)
{
        int ret;

        if (!buf && !oob_buf)
                return -EINVAL;

        ret = nand_read_page_op(chip, page, 0, NULL, 0);
        if (ret)
                return ret;

        if (buf) {
                ret = denali_payload_xfer(chip, buf, false);
                if (ret)
                        return ret;
        }

        if (oob_buf) {
                ret = denali_oob_xfer(chip, oob_buf, false);
                if (ret)
                        return ret;
        }

        return 0;
}

static int denali_write_raw(struct nand_chip *chip, const void *buf,
                            const void *oob_buf, int page)
{
        int ret;

        if (!buf && !oob_buf)
                return -EINVAL;

        ret = nand_prog_page_begin_op(chip, page, 0, NULL, 0);
        if (ret)
                return ret;

        if (buf) {
                ret = denali_payload_xfer(chip, (void *)buf, true);
                if (ret)
                        return ret;
        }

        if (oob_buf) {
                ret = denali_oob_xfer(chip, (void *)oob_buf, true);
                if (ret)
                        return ret;
        }

        return nand_prog_page_end_op(chip);
}

static int denali_read_page_raw(struct nand_chip *chip, u8 *buf,
                                int oob_required, int page)
{
        return denali_read_raw(chip, buf, oob_required ? chip->oob_poi : NULL,
                               page);
}

static int denali_write_page_raw(struct nand_chip *chip, const u8 *buf,
                                 int oob_required, int page)
{
        return denali_write_raw(chip, buf, oob_required ? chip->oob_poi : NULL,
                                page);
}

static int denali_read_oob(struct nand_chip *chip, int page)
{
        return denali_read_raw(chip, NULL, chip->oob_poi, page);
}

static int denali_write_oob(struct nand_chip *chip, int page)
{
        return denali_write_raw(chip, NULL, chip->oob_poi, page);
}

static int denali_check_erased_page(struct nand_chip *chip, u8 *buf,
                                    unsigned long uncor_ecc_flags,
                                    unsigned int max_bitflips)
{
        struct denali_controller *denali = to_denali_controller(chip);
        struct mtd_ecc_stats *ecc_stats = &nand_to_mtd(chip)->ecc_stats;
        struct nand_ecc_ctrl *ecc = &chip->ecc;
        u8 *ecc_code = chip->oob_poi + denali->oob_skip_bytes;
        int i, stat;

        for (i = 0; i < ecc->steps; i++) {
                if (!(uncor_ecc_flags & BIT(i)))
                        continue;

                stat = nand_check_erased_ecc_chunk(buf, ecc->size, ecc_code,
                                                   ecc->bytes, NULL, 0,
                                                   ecc->strength);
                if (stat < 0) {
                        ecc_stats->failed++;
                } else {
                        ecc_stats->corrected += stat;
                        max_bitflips = max_t(unsigned int, max_bitflips, stat);
                }

                buf += ecc->size;
                ecc_code += ecc->bytes;
        }

        return max_bitflips;
}

static int denali_hw_ecc_fixup(struct nand_chip *chip,
                               unsigned long *uncor_ecc_flags)
{
        struct denali_controller *denali = to_denali_controller(chip);
        struct mtd_ecc_stats *ecc_stats = &nand_to_mtd(chip)->ecc_stats;
        int bank = denali->active_bank;
        u32 ecc_cor;
        unsigned int max_bitflips;

        ecc_cor = ioread32(denali->reg + ECC_COR_INFO(bank));
        ecc_cor >>= ECC_COR_INFO__SHIFT(bank);

        if (ecc_cor & ECC_COR_INFO__UNCOR_ERR) {
                /*
                 * This flag is set when uncorrectable error occurs at least in
                 * one ECC sector.  We can not know "how many sectors", or
                 * "which sector(s)".  We need erase-page check for all sectors.
                 */
                *uncor_ecc_flags = GENMASK(chip->ecc.steps - 1, 0);
                return 0;
        }

        max_bitflips = FIELD_GET(ECC_COR_INFO__MAX_ERRORS, ecc_cor);

        /*
         * The register holds the maximum of per-sector corrected bitflips.
         * This is suitable for the return value of the ->read_page() callback.
         * Unfortunately, we can not know the total number of corrected bits in
         * the page.  Increase the stats by max_bitflips. (compromised solution)
         */
        ecc_stats->corrected += max_bitflips;

        return max_bitflips;
}

static int denali_sw_ecc_fixup(struct nand_chip *chip,
                               unsigned long *uncor_ecc_flags, u8 *buf)
{
        struct denali_controller *denali = to_denali_controller(chip);
        struct mtd_ecc_stats *ecc_stats = &nand_to_mtd(chip)->ecc_stats;
        unsigned int ecc_size = chip->ecc.size;
        unsigned int bitflips = 0;
        unsigned int max_bitflips = 0;
        u32 err_addr, err_cor_info;
        unsigned int err_byte, err_sector, err_device;
        u8 err_cor_value;
        unsigned int prev_sector = 0;
        u32 irq_status;

        denali_reset_irq(denali);

        do {
                err_addr = ioread32(denali->reg + ECC_ERROR_ADDRESS);
                err_sector = FIELD_GET(ECC_ERROR_ADDRESS__SECTOR, err_addr);
                err_byte = FIELD_GET(ECC_ERROR_ADDRESS__OFFSET, err_addr);

                err_cor_info = ioread32(denali->reg + ERR_CORRECTION_INFO);
                err_cor_value = FIELD_GET(ERR_CORRECTION_INFO__BYTE,
                                          err_cor_info);
                err_device = FIELD_GET(ERR_CORRECTION_INFO__DEVICE,
                                       err_cor_info);

                /* reset the bitflip counter when crossing ECC sector */
                if (err_sector != prev_sector)
                        bitflips = 0;

                if (err_cor_info & ERR_CORRECTION_INFO__UNCOR) {
                        /*
                         * Check later if this is a real ECC error, or
                         * an erased sector.
                         */
                        *uncor_ecc_flags |= BIT(err_sector);
                } else if (err_byte < ecc_size) {
                        /*
                         * If err_byte is larger than ecc_size, means error
                         * happened in OOB, so we ignore it. It's no need for
                         * us to correct it err_device is represented the NAND
                         * error bits are happened in if there are more than
                         * one NAND connected.
                         */
                        int offset;
                        unsigned int flips_in_byte;

                        offset = (err_sector * ecc_size + err_byte) *
                                        denali->devs_per_cs + err_device;

                        /* correct the ECC error */
                        flips_in_byte = hweight8(buf[offset] ^ err_cor_value);
                        buf[offset] ^= err_cor_value;
                        ecc_stats->corrected += flips_in_byte;
                        bitflips += flips_in_byte;

                        max_bitflips = max(max_bitflips, bitflips);
                }

                prev_sector = err_sector;
        } while (!(err_cor_info & ERR_CORRECTION_INFO__LAST_ERR));

        /*
         * Once handle all ECC errors, controller will trigger an
         * ECC_TRANSACTION_DONE interrupt.
         */
        irq_status = denali_wait_for_irq(denali, INTR__ECC_TRANSACTION_DONE);
        if (!(irq_status & INTR__ECC_TRANSACTION_DONE))
                return -EIO;

        return max_bitflips;
}

static void denali_setup_dma64(struct denali_controller *denali,
                               dma_addr_t dma_addr, int page, bool write)
{
        u32 mode;
        const int page_count = 1;

        mode = DENALI_MAP10 | DENALI_BANK(denali) | page;

        /* DMA is a three step process */

        /*
         * 1. setup transfer type, interrupt when complete,
         *    burst len = 64 bytes, the number of pages
         */
        denali->host_write(denali, mode,
                           0x01002000 | (64 << 16) |
                           (write ? BIT(8) : 0) | page_count);

        /* 2. set memory low address */
        denali->host_write(denali, mode, lower_32_bits(dma_addr));

        /* 3. set memory high address */
        denali->host_write(denali, mode, upper_32_bits(dma_addr));
}

static void denali_setup_dma32(struct denali_controller *denali,
                               dma_addr_t dma_addr, int page, bool write)
{
        u32 mode;
        const int page_count = 1;

        mode = DENALI_MAP10 | DENALI_BANK(denali);

        /* DMA is a four step process */

        /* 1. setup transfer type and # of pages */
        denali->host_write(denali, mode | page,
                           0x2000 | (write ? BIT(8) : 0) | page_count);

        /* 2. set memory high address bits 23:8 */
        denali->host_write(denali, mode | ((dma_addr >> 16) << 8), 0x2200);

        /* 3. set memory low address bits 23:8 */
        denali->host_write(denali, mode | ((dma_addr & 0xffff) << 8), 0x2300);

        /* 4. interrupt when complete, burst len = 64 bytes */
        denali->host_write(denali, mode | 0x14000, 0x2400);
}

static int denali_pio_read(struct denali_controller *denali, u32 *buf,
                           size_t size, int page)
{
        u32 addr = DENALI_MAP01 | DENALI_BANK(denali) | page;
        u32 irq_status, ecc_err_mask;
        int i;

        if (denali->caps & DENALI_CAP_HW_ECC_FIXUP)
                ecc_err_mask = INTR__ECC_UNCOR_ERR;
        else
                ecc_err_mask = INTR__ECC_ERR;

        denali_reset_irq(denali);

        for (i = 0; i < size / 4; i++)
                buf[i] = denali->host_read(denali, addr);

        irq_status = denali_wait_for_irq(denali, INTR__PAGE_XFER_INC);
        if (!(irq_status & INTR__PAGE_XFER_INC))
                return -EIO;

        if (irq_status & INTR__ERASED_PAGE)
                memset(buf, 0xff, size);

        return irq_status & ecc_err_mask ? -EBADMSG : 0;
}

static int denali_pio_write(struct denali_controller *denali, const u32 *buf,
                            size_t size, int page)
{
        u32 addr = DENALI_MAP01 | DENALI_BANK(denali) | page;
        u32 irq_status;
        int i;

        denali_reset_irq(denali);

        for (i = 0; i < size / 4; i++)
                denali->host_write(denali, addr, buf[i]);

        irq_status = denali_wait_for_irq(denali,
                                         INTR__PROGRAM_COMP |
                                         INTR__PROGRAM_FAIL);
        if (!(irq_status & INTR__PROGRAM_COMP))
                return -EIO;

        return 0;
}

static int denali_pio_xfer(struct denali_controller *denali, void *buf,
                           size_t size, int page, bool write)
{
        if (write)
                return denali_pio_write(denali, buf, size, page);
        else
                return denali_pio_read(denali, buf, size, page);
}

static int denali_dma_xfer(struct denali_controller *denali, void *buf,
                           size_t size, int page, bool write)
{
        dma_addr_t dma_addr;
        u32 irq_mask, irq_status, ecc_err_mask;
        enum dma_data_direction dir = write ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
        int ret = 0;

        dma_addr = dma_map_single(denali->dev, buf, size, dir);
        if (dma_mapping_error(denali->dev, dma_addr)) {
                dev_dbg(denali->dev, "Failed to DMA-map buffer. Trying PIO.\n");
                return denali_pio_xfer(denali, buf, size, page, write);
        }

        if (write) {
                /*
                 * INTR__PROGRAM_COMP is never asserted for the DMA transfer.
                 * We can use INTR__DMA_CMD_COMP instead.  This flag is asserted
                 * when the page program is completed.
                 */
                irq_mask = INTR__DMA_CMD_COMP | INTR__PROGRAM_FAIL;
                ecc_err_mask = 0;
        } else if (denali->caps & DENALI_CAP_HW_ECC_FIXUP) {
                irq_mask = INTR__DMA_CMD_COMP;
                ecc_err_mask = INTR__ECC_UNCOR_ERR;
        } else {
                irq_mask = INTR__DMA_CMD_COMP;
                ecc_err_mask = INTR__ECC_ERR;
        }

        iowrite32(DMA_ENABLE__FLAG, denali->reg + DMA_ENABLE);
        /*
         * The ->setup_dma() hook kicks DMA by using the data/command
         * interface, which belongs to a different AXI port from the
         * register interface.  Read back the register to avoid a race.
         */
        ioread32(denali->reg + DMA_ENABLE);

        denali_reset_irq(denali);
        denali->setup_dma(denali, dma_addr, page, write);

        irq_status = denali_wait_for_irq(denali, irq_mask);
        if (!(irq_status & INTR__DMA_CMD_COMP))
                ret = -EIO;
        else if (irq_status & ecc_err_mask)
                ret = -EBADMSG;

        iowrite32(0, denali->reg + DMA_ENABLE);

        dma_unmap_single(denali->dev, dma_addr, size, dir);

        if (irq_status & INTR__ERASED_PAGE)
                memset(buf, 0xff, size);

        return ret;
}

static int denali_page_xfer(struct nand_chip *chip, void *buf, size_t size,
                            int page, bool write)
{
        struct denali_controller *denali = to_denali_controller(chip);

        denali_select_target(chip, chip->cur_cs);

        if (denali->dma_avail)
                return denali_dma_xfer(denali, buf, size, page, write);
        else
                return denali_pio_xfer(denali, buf, size, page, write);
}

static int denali_read_page(struct nand_chip *chip, u8 *buf,
                            int oob_required, int page)
{
        struct denali_controller *denali = to_denali_controller(chip);
        struct mtd_info *mtd = nand_to_mtd(chip);
        unsigned long uncor_ecc_flags = 0;
        int stat = 0;
        int ret;

        ret = denali_page_xfer(chip, buf, mtd->writesize, page, false);
        if (ret && ret != -EBADMSG)
                return ret;

        if (denali->caps & DENALI_CAP_HW_ECC_FIXUP)
                stat = denali_hw_ecc_fixup(chip, &uncor_ecc_flags);
        else if (ret == -EBADMSG)
                stat = denali_sw_ecc_fixup(chip, &uncor_ecc_flags, buf);

        if (stat < 0)
                return stat;

        if (uncor_ecc_flags) {
                ret = denali_read_oob(chip, page);
                if (ret)
                        return ret;

                stat = denali_check_erased_page(chip, buf,
                                                uncor_ecc_flags, stat);
        }

        return stat;
}

static int denali_write_page(struct nand_chip *chip, const u8 *buf,
                             int oob_required, int page)
{
        struct mtd_info *mtd = nand_to_mtd(chip);

        return denali_page_xfer(chip, (void *)buf, mtd->writesize, page, true);
}

static int denali_setup_interface(struct nand_chip *chip, int chipnr,
                                  const struct nand_interface_config *conf)
{
        static const unsigned int data_setup_on_host = 10000;
        struct denali_controller *denali = to_denali_controller(chip);
        struct denali_chip_sel *sel;
        const struct nand_sdr_timings *timings;
        unsigned long t_x, mult_x;
        int acc_clks, re_2_we, re_2_re, we_2_re, addr_2_data;
        int rdwr_en_lo, rdwr_en_hi, rdwr_en_lo_hi, cs_setup;
        int addr_2_data_mask;
        u32 tmp;

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

        /* clk_x period in picoseconds */
        t_x = DIV_ROUND_DOWN_ULL(1000000000000ULL, denali->clk_x_rate);
        if (!t_x)
                return -EINVAL;

        /*
         * The bus interface clock, clk_x, is phase aligned with the core clock.
         * The clk_x is an integral multiple N of the core clk.  The value N is
         * configured at IP delivery time, and its available value is 4, 5, 6.
         */
        mult_x = DIV_ROUND_CLOSEST_ULL(denali->clk_x_rate, denali->clk_rate);
        if (mult_x < 4 || mult_x > 6)
                return -EINVAL;

        if (chipnr == NAND_DATA_IFACE_CHECK_ONLY)
                return 0;

        sel = &to_denali_chip(chip)->sels[chipnr];

        /* tRWH -> RE_2_WE */
        re_2_we = DIV_ROUND_UP(timings->tRHW_min, t_x);
        re_2_we = min_t(int, re_2_we, RE_2_WE__VALUE);

        tmp = ioread32(denali->reg + RE_2_WE);
        tmp &= ~RE_2_WE__VALUE;
        tmp |= FIELD_PREP(RE_2_WE__VALUE, re_2_we);
        sel->re_2_we = tmp;

        /* tRHZ -> RE_2_RE */
        re_2_re = DIV_ROUND_UP(timings->tRHZ_max, t_x);
        re_2_re = min_t(int, re_2_re, RE_2_RE__VALUE);

        tmp = ioread32(denali->reg + RE_2_RE);
        tmp &= ~RE_2_RE__VALUE;
        tmp |= FIELD_PREP(RE_2_RE__VALUE, re_2_re);
        sel->re_2_re = tmp;

        /*
         * tCCS, tWHR -> WE_2_RE
         *
         * With WE_2_RE properly set, the Denali controller automatically takes
         * care of the delay; the driver need not set NAND_WAIT_TCCS.
         */
        we_2_re = DIV_ROUND_UP(max(timings->tCCS_min, timings->tWHR_min), t_x);
        we_2_re = min_t(int, we_2_re, TWHR2_AND_WE_2_RE__WE_2_RE);

        tmp = ioread32(denali->reg + TWHR2_AND_WE_2_RE);
        tmp &= ~TWHR2_AND_WE_2_RE__WE_2_RE;
        tmp |= FIELD_PREP(TWHR2_AND_WE_2_RE__WE_2_RE, we_2_re);
        sel->hwhr2_and_we_2_re = tmp;

        /* tADL -> ADDR_2_DATA */

        /* for older versions, ADDR_2_DATA is only 6 bit wide */
        addr_2_data_mask = TCWAW_AND_ADDR_2_DATA__ADDR_2_DATA;
        if (denali->revision < 0x0501)
                addr_2_data_mask >>= 1;

        addr_2_data = DIV_ROUND_UP(timings->tADL_min, t_x);
        addr_2_data = min_t(int, addr_2_data, addr_2_data_mask);

        tmp = ioread32(denali->reg + TCWAW_AND_ADDR_2_DATA);
        tmp &= ~TCWAW_AND_ADDR_2_DATA__ADDR_2_DATA;
        tmp |= FIELD_PREP(TCWAW_AND_ADDR_2_DATA__ADDR_2_DATA, addr_2_data);
        sel->tcwaw_and_addr_2_data = tmp;

        /* tREH, tWH -> RDWR_EN_HI_CNT */
        rdwr_en_hi = DIV_ROUND_UP(max(timings->tREH_min, timings->tWH_min),
                                  t_x);
        rdwr_en_hi = min_t(int, rdwr_en_hi, RDWR_EN_HI_CNT__VALUE);

        tmp = ioread32(denali->reg + RDWR_EN_HI_CNT);
        tmp &= ~RDWR_EN_HI_CNT__VALUE;
        tmp |= FIELD_PREP(RDWR_EN_HI_CNT__VALUE, rdwr_en_hi);
        sel->rdwr_en_hi_cnt = tmp;

        /*
         * tREA -> ACC_CLKS
         * tRP, tWP, tRHOH, tRC, tWC -> RDWR_EN_LO_CNT
         */

        /*
         * Determine the minimum of acc_clks to meet the setup timing when
         * capturing the incoming data.
         *
         * The delay on the chip side is well-defined as tREA, but we need to
         * take additional delay into account. This includes a certain degree
         * of unknowledge, such as signal propagation delays on the PCB and
         * in the SoC, load capacity of the I/O pins, etc.
         */
        acc_clks = DIV_ROUND_UP(timings->tREA_max + data_setup_on_host, t_x);

        /* Determine the minimum of rdwr_en_lo_cnt from RE#/WE# pulse width */
        rdwr_en_lo = DIV_ROUND_UP(max(timings->tRP_min, timings->tWP_min), t_x);

        /* Extend rdwr_en_lo to meet the data hold timing */
        rdwr_en_lo = max_t(int, rdwr_en_lo,
                           acc_clks - timings->tRHOH_min / t_x);

        /* Extend rdwr_en_lo to meet the requirement for RE#/WE# cycle time */
        rdwr_en_lo_hi = DIV_ROUND_UP(max(timings->tRC_min, timings->tWC_min),
                                     t_x);
        rdwr_en_lo = max(rdwr_en_lo, rdwr_en_lo_hi - rdwr_en_hi);
        rdwr_en_lo = min_t(int, rdwr_en_lo, RDWR_EN_LO_CNT__VALUE);

        /* Center the data latch timing for extra safety */
        acc_clks = (acc_clks + rdwr_en_lo +
                    DIV_ROUND_UP(timings->tRHOH_min, t_x)) / 2;
        acc_clks = min_t(int, acc_clks, ACC_CLKS__VALUE);

        tmp = ioread32(denali->reg + ACC_CLKS);
        tmp &= ~ACC_CLKS__VALUE;
        tmp |= FIELD_PREP(ACC_CLKS__VALUE, acc_clks);
        sel->acc_clks = tmp;

        tmp = ioread32(denali->reg + RDWR_EN_LO_CNT);
        tmp &= ~RDWR_EN_LO_CNT__VALUE;
        tmp |= FIELD_PREP(RDWR_EN_LO_CNT__VALUE, rdwr_en_lo);
        sel->rdwr_en_lo_cnt = tmp;

        /* tCS, tCEA -> CS_SETUP_CNT */
        cs_setup = max3((int)DIV_ROUND_UP(timings->tCS_min, t_x) - rdwr_en_lo,
                        (int)DIV_ROUND_UP(timings->tCEA_max, t_x) - acc_clks,
                        0);
        cs_setup = min_t(int, cs_setup, CS_SETUP_CNT__VALUE);

        tmp = ioread32(denali->reg + CS_SETUP_CNT);
        tmp &= ~CS_SETUP_CNT__VALUE;
        tmp |= FIELD_PREP(CS_SETUP_CNT__VALUE, cs_setup);
        sel->cs_setup_cnt = tmp;

        return 0;
}

int denali_calc_ecc_bytes(int step_size, int strength)
{
        /* BCH code.  Denali requires ecc.bytes to be multiple of 2 */
        return DIV_ROUND_UP(strength * fls(step_size * 8), 16) * 2;
}
EXPORT_SYMBOL(denali_calc_ecc_bytes);

static int denali_ooblayout_ecc(struct mtd_info *mtd, int section,
                                struct mtd_oob_region *oobregion)
{
        struct nand_chip *chip = mtd_to_nand(mtd);
        struct denali_controller *denali = to_denali_controller(chip);

        if (section > 0)
                return -ERANGE;

        oobregion->offset = denali->oob_skip_bytes;
        oobregion->length = chip->ecc.total;

        return 0;
}

static int denali_ooblayout_free(struct mtd_info *mtd, int section,
                                 struct mtd_oob_region *oobregion)
{
        struct nand_chip *chip = mtd_to_nand(mtd);
        struct denali_controller *denali = to_denali_controller(chip);

        if (section > 0)
                return -ERANGE;

        oobregion->offset = chip->ecc.total + denali->oob_skip_bytes;
        oobregion->length = mtd->oobsize - oobregion->offset;

        return 0;
}

static const struct mtd_ooblayout_ops denali_ooblayout_ops = {
        .ecc = denali_ooblayout_ecc,
        .free = denali_ooblayout_free,
};

static int denali_multidev_fixup(struct nand_chip *chip)
{
        struct denali_controller *denali = to_denali_controller(chip);
        struct mtd_info *mtd = nand_to_mtd(chip);
        struct nand_memory_organization *memorg;

        memorg = nanddev_get_memorg(&chip->base);

        /*
         * Support for multi device:
         * When the IP configuration is x16 capable and two x8 chips are
         * connected in parallel, DEVICES_CONNECTED should be set to 2.
         * In this case, the core framework knows nothing about this fact,
         * so we should tell it the _logical_ pagesize and anything necessary.
         */
        denali->devs_per_cs = ioread32(denali->reg + DEVICES_CONNECTED);

        /*
         * On some SoCs, DEVICES_CONNECTED is not auto-detected.
         * For those, DEVICES_CONNECTED is left to 0.  Set 1 if it is the case.
         */
        if (denali->devs_per_cs == 0) {
                denali->devs_per_cs = 1;
                iowrite32(1, denali->reg + DEVICES_CONNECTED);
        }

        if (denali->devs_per_cs == 1)
                return 0;

        if (denali->devs_per_cs != 2) {
                dev_err(denali->dev, "unsupported number of devices %d\n",
                        denali->devs_per_cs);
                return -EINVAL;
        }

        /* 2 chips in parallel */
        memorg->pagesize <<= 1;
        memorg->oobsize <<= 1;
        mtd->size <<= 1;
        mtd->erasesize <<= 1;
        mtd->writesize <<= 1;
        mtd->oobsize <<= 1;
        chip->page_shift += 1;
        chip->phys_erase_shift += 1;

        chip->bbt_erase_shift += 1;
        chip->chip_shift += 1;
        chip->pagemask <<= 1;
        chip->ecc.size <<= 1;
        chip->ecc.bytes <<= 1;
        chip->ecc.strength <<= 1;
        denali->oob_skip_bytes <<= 1;

        return 0;
}

static int denali_attach_chip(struct nand_chip *chip)
{
        struct denali_controller *denali = to_denali_controller(chip);
        struct mtd_info *mtd = nand_to_mtd(chip);
        int ret;

        ret = nand_ecc_choose_conf(chip, denali->ecc_caps,
                                   mtd->oobsize - denali->oob_skip_bytes);
        if (ret) {
                dev_err(denali->dev, "Failed to setup ECC settings.\n");
                return ret;
        }

        dev_dbg(denali->dev,
                "chosen ECC settings: step=%d, strength=%d, bytes=%d\n",
                chip->ecc.size, chip->ecc.strength, chip->ecc.bytes);

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

        return 0;
}

static void denali_exec_in8(struct denali_controller *denali, u32 type,
                            u8 *buf, unsigned int len)
{
        int i;

        for (i = 0; i < len; i++)
                buf[i] = denali->host_read(denali, type | DENALI_BANK(denali));
}

static void denali_exec_in16(struct denali_controller *denali, u32 type,
                             u8 *buf, unsigned int len)
{
        u32 data;
        int i;

        for (i = 0; i < len; i += 2) {
                data = denali->host_read(denali, type | DENALI_BANK(denali));
                /* bit 31:24 and 15:8 are used for DDR */
                buf[i] = data;
                buf[i + 1] = data >> 16;
        }
}

static void denali_exec_in(struct denali_controller *denali, u32 type,
                           u8 *buf, unsigned int len, bool width16)
{
        if (width16)
                denali_exec_in16(denali, type, buf, len);
        else
                denali_exec_in8(denali, type, buf, len);
}

static void denali_exec_out8(struct denali_controller *denali, u32 type,
                             const u8 *buf, unsigned int len)
{
        int i;

        for (i = 0; i < len; i++)
                denali->host_write(denali, type | DENALI_BANK(denali), buf[i]);
}

static void denali_exec_out16(struct denali_controller *denali, u32 type,
                              const u8 *buf, unsigned int len)
{
        int i;

        for (i = 0; i < len; i += 2)
                denali->host_write(denali, type | DENALI_BANK(denali),
                                   buf[i + 1] << 16 | buf[i]);
}

static void denali_exec_out(struct denali_controller *denali, u32 type,
                            const u8 *buf, unsigned int len, bool width16)
{
        if (width16)
                denali_exec_out16(denali, type, buf, len);
        else
                denali_exec_out8(denali, type, buf, len);
}

static int denali_exec_waitrdy(struct denali_controller *denali)
{
        u32 irq_stat;

        /* R/B# pin transitioned from low to high? */
        irq_stat = denali_wait_for_irq(denali, INTR__INT_ACT);

        /* Just in case nand_operation has multiple NAND_OP_WAITRDY_INSTR. */
        denali_reset_irq(denali);

        return irq_stat & INTR__INT_ACT ? 0 : -EIO;
}

static int denali_exec_instr(struct nand_chip *chip,
                             const struct nand_op_instr *instr)
{
        struct denali_controller *denali = to_denali_controller(chip);

        switch (instr->type) {
        case NAND_OP_CMD_INSTR:
                denali_exec_out8(denali, DENALI_MAP11_CMD,
                                 &instr->ctx.cmd.opcode, 1);
                return 0;
        case NAND_OP_ADDR_INSTR:
                denali_exec_out8(denali, DENALI_MAP11_ADDR,
                                 instr->ctx.addr.addrs,
                                 instr->ctx.addr.naddrs);
                return 0;
        case NAND_OP_DATA_IN_INSTR:
                denali_exec_in(denali, DENALI_MAP11_DATA,
                               instr->ctx.data.buf.in,
                               instr->ctx.data.len,
                               !instr->ctx.data.force_8bit &&
                               chip->options & NAND_BUSWIDTH_16);
                return 0;
        case NAND_OP_DATA_OUT_INSTR:
                denali_exec_out(denali, DENALI_MAP11_DATA,
                                instr->ctx.data.buf.out,
                                instr->ctx.data.len,
                                !instr->ctx.data.force_8bit &&
                                chip->options & NAND_BUSWIDTH_16);
                return 0;
        case NAND_OP_WAITRDY_INSTR:
                return denali_exec_waitrdy(denali);
        default:
                WARN_ONCE(1, "unsupported NAND instruction type: %d\n",
                          instr->type);

                return -EINVAL;
        }
}

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

        if (check_only)
                return 0;

        denali_select_target(chip, op->cs);

        /*
         * Some commands contain NAND_OP_WAITRDY_INSTR.
         * irq must be cleared here to catch the R/B# interrupt there.
         */
        denali_reset_irq(to_denali_controller(chip));

        for (i = 0; i < op->ninstrs; i++) {
                ret = denali_exec_instr(chip, &op->instrs[i]);
                if (ret)
                        return ret;
        }

        return 0;
}

static const struct nand_controller_ops denali_controller_ops = {
        .attach_chip = denali_attach_chip,
        .exec_op = denali_exec_op,
        .setup_interface = denali_setup_interface,
};

int denali_chip_init(struct denali_controller *denali,
                     struct denali_chip *dchip)
{
        struct nand_chip *chip = &dchip->chip;
        struct mtd_info *mtd = nand_to_mtd(chip);
        struct denali_chip *dchip2;
        int i, j, ret;

        chip->controller = &denali->controller;

        /* sanity checks for bank numbers */
        for (i = 0; i < dchip->nsels; i++) {
                unsigned int bank = dchip->sels[i].bank;

                if (bank >= denali->nbanks) {
                        dev_err(denali->dev, "unsupported bank %d\n", bank);
                        return -EINVAL;
                }

                for (j = 0; j < i; j++) {
                        if (bank == dchip->sels[j].bank) {
                                dev_err(denali->dev,
                                        "bank %d is assigned twice in the same chip\n",
                                        bank);
                                return -EINVAL;
                        }
                }

                list_for_each_entry(dchip2, &denali->chips, node) {
                        for (j = 0; j < dchip2->nsels; j++) {
                                if (bank == dchip2->sels[j].bank) {
                                        dev_err(denali->dev,
                                                "bank %d is already used\n",
                                                bank);
                                        return -EINVAL;
                                }
                        }
                }
        }

        mtd->dev.parent = denali->dev;

        /*
         * Fallback to the default name if DT did not give "label" property.
         * Use "label" property if multiple chips are connected.
         */
        if (!mtd->name && list_empty(&denali->chips))
                mtd->name = "denali-nand";

        if (denali->dma_avail) {
                chip->options |= NAND_USES_DMA;
                chip->buf_align = 16;
        }

        /* clk rate info is needed for setup_interface */
        if (!denali->clk_rate || !denali->clk_x_rate)
                chip->options |= NAND_KEEP_TIMINGS;

        chip->bbt_options |= NAND_BBT_USE_FLASH;
        chip->bbt_options |= NAND_BBT_NO_OOB;
        chip->options |= NAND_NO_SUBPAGE_WRITE;
        chip->ecc.engine_type = NAND_ECC_ENGINE_TYPE_ON_HOST;
        chip->ecc.placement = NAND_ECC_PLACEMENT_INTERLEAVED;
        chip->ecc.read_page = denali_read_page;
        chip->ecc.write_page = denali_write_page;
        chip->ecc.read_page_raw = denali_read_page_raw;
        chip->ecc.write_page_raw = denali_write_page_raw;
        chip->ecc.read_oob = denali_read_oob;
        chip->ecc.write_oob = denali_write_oob;

        mtd_set_ooblayout(mtd, &denali_ooblayout_ops);

        ret = nand_scan(chip, dchip->nsels);
        if (ret)
                return ret;

        ret = mtd_device_register(mtd, NULL, 0);
        if (ret) {
                dev_err(denali->dev, "Failed to register MTD: %d\n", ret);
                goto cleanup_nand;
        }

        list_add_tail(&dchip->node, &denali->chips);

        return 0;

cleanup_nand:
        nand_cleanup(chip);

        return ret;
}
EXPORT_SYMBOL_GPL(denali_chip_init);

int denali_init(struct denali_controller *denali)
{
        u32 features = ioread32(denali->reg + FEATURES);
        int ret;

        nand_controller_init(&denali->controller);
        denali->controller.ops = &denali_controller_ops;
        init_completion(&denali->complete);
        spin_lock_init(&denali->irq_lock);
        INIT_LIST_HEAD(&denali->chips);
        denali->active_bank = DENALI_INVALID_BANK;

        /*
         * The REVISION register may not be reliable. Platforms are allowed to
         * override it.
         */
        if (!denali->revision)
                denali->revision = swab16(ioread32(denali->reg + REVISION));

        denali->nbanks = 1 << FIELD_GET(FEATURES__N_BANKS, features);

        /* the encoding changed from rev 5.0 to 5.1 */
        if (denali->revision < 0x0501)
                denali->nbanks <<= 1;

        if (features & FEATURES__DMA)
                denali->dma_avail = true;

        if (denali->dma_avail) {
                int dma_bit = denali->caps & DENALI_CAP_DMA_64BIT ? 64 : 32;

                ret = dma_set_mask(denali->dev, DMA_BIT_MASK(dma_bit));
                if (ret) {
                        dev_info(denali->dev,
                                 "Failed to set DMA mask. Disabling DMA.\n");
                        denali->dma_avail = false;
                }
        }

        if (denali->dma_avail) {
                if (denali->caps & DENALI_CAP_DMA_64BIT)
                        denali->setup_dma = denali_setup_dma64;
                else
                        denali->setup_dma = denali_setup_dma32;
        }

        if (features & FEATURES__INDEX_ADDR) {
                denali->host_read = denali_indexed_read;
                denali->host_write = denali_indexed_write;
        } else {
                denali->host_read = denali_direct_read;
                denali->host_write = denali_direct_write;
        }

        /*
         * Set how many bytes should be skipped before writing data in OOB.
         * If a platform requests a non-zero value, set it to the register.
         * Otherwise, read the value out, expecting it has already been set up
         * by firmware.
         */
        if (denali->oob_skip_bytes)
                iowrite32(denali->oob_skip_bytes,
                          denali->reg + SPARE_AREA_SKIP_BYTES);
        else
                denali->oob_skip_bytes = ioread32(denali->reg +
                                                  SPARE_AREA_SKIP_BYTES);

        iowrite32(0, denali->reg + TRANSFER_SPARE_REG);
        iowrite32(GENMASK(denali->nbanks - 1, 0), denali->reg + RB_PIN_ENABLED);
        iowrite32(CHIP_EN_DONT_CARE__FLAG, denali->reg + CHIP_ENABLE_DONT_CARE);
        iowrite32(ECC_ENABLE__FLAG, denali->reg + ECC_ENABLE);
        iowrite32(0xffff, denali->reg + SPARE_AREA_MARKER);
        iowrite32(WRITE_PROTECT__FLAG, denali->reg + WRITE_PROTECT);

        denali_clear_irq_all(denali);

        ret = devm_request_irq(denali->dev, denali->irq, denali_isr,
                               IRQF_SHARED, DENALI_NAND_NAME, denali);
        if (ret) {
                dev_err(denali->dev, "Unable to request IRQ\n");
                return ret;
        }

        denali_enable_irq(denali);

        return 0;
}
EXPORT_SYMBOL(denali_init);

void denali_remove(struct denali_controller *denali)
{
        struct denali_chip *dchip, *tmp;
        struct nand_chip *chip;
        int ret;

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

        denali_disable_irq(denali);
}
EXPORT_SYMBOL(denali_remove);

MODULE_DESCRIPTION("Driver core for Denali NAND controller");
MODULE_AUTHOR("Intel Corporation and its suppliers");
MODULE_LICENSE("GPL v2");