// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Driver for NAND MLC Controller in LPC32xx
 *
 * Author: Roland Stigge <stigge@antcom.de>
 *
 * Copyright © 2011 WORK Microwave GmbH
 * Copyright © 2011, 2012 Roland Stigge
 *
 * NAND Flash Controller Operation:
 * - Read: Auto Decode
 * - Write: Auto Encode
 * - Tested Page Sizes: 2048, 4096
 */

#include <linux/slab.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/rawnand.h>
#include <linux/mtd/partitions.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/delay.h>
#include <linux/completion.h>
#include <linux/interrupt.h>
#include <linux/of.h>
#include <linux/gpio/consumer.h>
#include <linux/mtd/lpc32xx_mlc.h>
#include <linux/io.h>
#include <linux/mm.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>

#define DRV_NAME "lpc32xx_mlc"

/**********************************************************************
* MLC NAND controller register offsets
**********************************************************************/

#define MLC_BUFF(x)                     (x + 0x00000)
#define MLC_DATA(x)                     (x + 0x08000)
#define MLC_CMD(x)                      (x + 0x10000)
#define MLC_ADDR(x)                     (x + 0x10004)
#define MLC_ECC_ENC_REG(x)              (x + 0x10008)
#define MLC_ECC_DEC_REG(x)              (x + 0x1000C)
#define MLC_ECC_AUTO_ENC_REG(x)         (x + 0x10010)
#define MLC_ECC_AUTO_DEC_REG(x)         (x + 0x10014)
#define MLC_RPR(x)                      (x + 0x10018)
#define MLC_WPR(x)                      (x + 0x1001C)
#define MLC_RUBP(x)                     (x + 0x10020)
#define MLC_ROBP(x)                     (x + 0x10024)
#define MLC_SW_WP_ADD_LOW(x)            (x + 0x10028)
#define MLC_SW_WP_ADD_HIG(x)            (x + 0x1002C)
#define MLC_ICR(x)                      (x + 0x10030)
#define MLC_TIME_REG(x)                 (x + 0x10034)
#define MLC_IRQ_MR(x)                   (x + 0x10038)
#define MLC_IRQ_SR(x)                   (x + 0x1003C)
#define MLC_LOCK_PR(x)                  (x + 0x10044)
#define MLC_ISR(x)                      (x + 0x10048)
#define MLC_CEH(x)                      (x + 0x1004C)

/**********************************************************************
* MLC_CMD bit definitions
**********************************************************************/
#define MLCCMD_RESET                    0xFF

/**********************************************************************
* MLC_ICR bit definitions
**********************************************************************/
#define MLCICR_WPROT                    (1 << 3)
#define MLCICR_LARGEBLOCK               (1 << 2)
#define MLCICR_LONGADDR                 (1 << 1)
#define MLCICR_16BIT                    (1 << 0)  /* unsupported by LPC32x0! */

/**********************************************************************
* MLC_TIME_REG bit definitions
**********************************************************************/
#define MLCTIMEREG_TCEA_DELAY(n)        (((n) & 0x03) << 24)
#define MLCTIMEREG_BUSY_DELAY(n)        (((n) & 0x1F) << 19)
#define MLCTIMEREG_NAND_TA(n)           (((n) & 0x07) << 16)
#define MLCTIMEREG_RD_HIGH(n)           (((n) & 0x0F) << 12)
#define MLCTIMEREG_RD_LOW(n)            (((n) & 0x0F) << 8)
#define MLCTIMEREG_WR_HIGH(n)           (((n) & 0x0F) << 4)
#define MLCTIMEREG_WR_LOW(n)            (((n) & 0x0F) << 0)

/**********************************************************************
* MLC_IRQ_MR and MLC_IRQ_SR bit definitions
**********************************************************************/
#define MLCIRQ_NAND_READY               (1 << 5)
#define MLCIRQ_CONTROLLER_READY         (1 << 4)
#define MLCIRQ_DECODE_FAILURE           (1 << 3)
#define MLCIRQ_DECODE_ERROR             (1 << 2)
#define MLCIRQ_ECC_READY                (1 << 1)
#define MLCIRQ_WRPROT_FAULT             (1 << 0)

/**********************************************************************
* MLC_LOCK_PR bit definitions
**********************************************************************/
#define MLCLOCKPR_MAGIC                 0xA25E

/**********************************************************************
* MLC_ISR bit definitions
**********************************************************************/
#define MLCISR_DECODER_FAILURE          (1 << 6)
#define MLCISR_ERRORS                   ((1 << 4) | (1 << 5))
#define MLCISR_ERRORS_DETECTED          (1 << 3)
#define MLCISR_ECC_READY                (1 << 2)
#define MLCISR_CONTROLLER_READY         (1 << 1)
#define MLCISR_NAND_READY               (1 << 0)

/**********************************************************************
* MLC_CEH bit definitions
**********************************************************************/
#define MLCCEH_NORMAL                   (1 << 0)

struct lpc32xx_nand_cfg_mlc {
        uint32_t tcea_delay;
        uint32_t busy_delay;
        uint32_t nand_ta;
        uint32_t rd_high;
        uint32_t rd_low;
        uint32_t wr_high;
        uint32_t wr_low;
        struct mtd_partition *parts;
        unsigned num_parts;
};

static int lpc32xx_ooblayout_ecc(struct mtd_info *mtd, int section,
                                 struct mtd_oob_region *oobregion)
{
        struct nand_chip *nand_chip = mtd_to_nand(mtd);

        if (section >= nand_chip->ecc.steps)
                return -ERANGE;

        oobregion->offset = ((section + 1) * 16) - nand_chip->ecc.bytes;
        oobregion->length = nand_chip->ecc.bytes;

        return 0;
}

static int lpc32xx_ooblayout_free(struct mtd_info *mtd, int section,
                                  struct mtd_oob_region *oobregion)
{
        struct nand_chip *nand_chip = mtd_to_nand(mtd);

        if (section >= nand_chip->ecc.steps)
                return -ERANGE;

        oobregion->offset = 16 * section;
        oobregion->length = 16 - nand_chip->ecc.bytes;

        return 0;
}

static const struct mtd_ooblayout_ops lpc32xx_ooblayout_ops = {
        .ecc = lpc32xx_ooblayout_ecc,
        .free = lpc32xx_ooblayout_free,
};

static struct nand_bbt_descr lpc32xx_nand_bbt = {
        .options = NAND_BBT_ABSPAGE | NAND_BBT_2BIT | NAND_BBT_NO_OOB |
                   NAND_BBT_WRITE,
        .pages = { 524224, 0, 0, 0, 0, 0, 0, 0 },
};

static struct nand_bbt_descr lpc32xx_nand_bbt_mirror = {
        .options = NAND_BBT_ABSPAGE | NAND_BBT_2BIT | NAND_BBT_NO_OOB |
                   NAND_BBT_WRITE,
        .pages = { 524160, 0, 0, 0, 0, 0, 0, 0 },
};

struct lpc32xx_nand_host {
        struct platform_device  *pdev;
        struct nand_chip        nand_chip;
        struct lpc32xx_mlc_platform_data *pdata;
        struct clk              *clk;
        struct gpio_desc        *wp_gpio;
        void __iomem            *io_base;
        int                     irq;
        struct lpc32xx_nand_cfg_mlc     *ncfg;
        struct completion       comp_nand;
        struct completion       comp_controller;
        uint32_t llptr;
        /*
         * Physical addresses of ECC buffer, DMA data buffers, OOB data buffer
         */
        dma_addr_t              oob_buf_phy;
        /*
         * Virtual addresses of ECC buffer, DMA data buffers, OOB data buffer
         */
        uint8_t                 *oob_buf;
        /* Physical address of DMA base address */
        dma_addr_t              io_base_phy;

        struct completion       comp_dma;
        struct dma_chan         *dma_chan;
        struct dma_slave_config dma_slave_config;
        struct scatterlist      sgl;
        uint8_t                 *dma_buf;
        uint8_t                 *dummy_buf;
        int                     mlcsubpages; /* number of 512bytes-subpages */
};

/*
 * Activate/Deactivate DMA Operation:
 *
 * Using the PL080 DMA Controller for transferring the 512 byte subpages
 * instead of doing readl() / writel() in a loop slows it down significantly.
 * Measurements via getnstimeofday() upon 512 byte subpage reads reveal:
 *
 * - readl() of 128 x 32 bits in a loop: ~20us
 * - DMA read of 512 bytes (32 bit, 4...128 words bursts): ~60us
 * - DMA read of 512 bytes (32 bit, no bursts): ~100us
 *
 * This applies to the transfer itself. In the DMA case: only the
 * wait_for_completion() (DMA setup _not_ included).
 *
 * Note that the 512 bytes subpage transfer is done directly from/to a
 * FIFO/buffer inside the NAND controller. Most of the time (~400-800us for a
 * 2048 bytes page) is spent waiting for the NAND IRQ, anyway. (The NAND
 * controller transferring data between its internal buffer to/from the NAND
 * chip.)
 *
 * Therefore, using the PL080 DMA is disabled by default, for now.
 *
 */
static int use_dma;

static void lpc32xx_nand_setup(struct lpc32xx_nand_host *host)
{
        uint32_t clkrate, tmp;

        /* Reset MLC controller */
        writel(MLCCMD_RESET, MLC_CMD(host->io_base));
        udelay(1000);

        /* Get base clock for MLC block */
        clkrate = clk_get_rate(host->clk);
        if (clkrate == 0)
                clkrate = 104000000;

        /* Unlock MLC_ICR
         * (among others, will be locked again automatically) */
        writew(MLCLOCKPR_MAGIC, MLC_LOCK_PR(host->io_base));

        /* Configure MLC Controller: Large Block, 5 Byte Address */
        tmp = MLCICR_LARGEBLOCK | MLCICR_LONGADDR;
        writel(tmp, MLC_ICR(host->io_base));

        /* Unlock MLC_TIME_REG
         * (among others, will be locked again automatically) */
        writew(MLCLOCKPR_MAGIC, MLC_LOCK_PR(host->io_base));

        /* Compute clock setup values, see LPC and NAND manual */
        tmp = 0;
        tmp |= MLCTIMEREG_TCEA_DELAY(clkrate / host->ncfg->tcea_delay + 1);
        tmp |= MLCTIMEREG_BUSY_DELAY(clkrate / host->ncfg->busy_delay + 1);
        tmp |= MLCTIMEREG_NAND_TA(clkrate / host->ncfg->nand_ta + 1);
        tmp |= MLCTIMEREG_RD_HIGH(clkrate / host->ncfg->rd_high + 1);
        tmp |= MLCTIMEREG_RD_LOW(clkrate / host->ncfg->rd_low);
        tmp |= MLCTIMEREG_WR_HIGH(clkrate / host->ncfg->wr_high + 1);
        tmp |= MLCTIMEREG_WR_LOW(clkrate / host->ncfg->wr_low);
        writel(tmp, MLC_TIME_REG(host->io_base));

        /* Enable IRQ for CONTROLLER_READY and NAND_READY */
        writeb(MLCIRQ_CONTROLLER_READY | MLCIRQ_NAND_READY,
                        MLC_IRQ_MR(host->io_base));

        /* Normal nCE operation: nCE controlled by controller */
        writel(MLCCEH_NORMAL, MLC_CEH(host->io_base));
}

/*
 * Hardware specific access to control lines
 */
static void lpc32xx_nand_cmd_ctrl(struct nand_chip *nand_chip, int cmd,
                                  unsigned int ctrl)
{
        struct lpc32xx_nand_host *host = nand_get_controller_data(nand_chip);

        if (cmd != NAND_CMD_NONE) {
                if (ctrl & NAND_CLE)
                        writel(cmd, MLC_CMD(host->io_base));
                else
                        writel(cmd, MLC_ADDR(host->io_base));
        }
}

/*
 * Read Device Ready (NAND device _and_ controller ready)
 */
static int lpc32xx_nand_device_ready(struct nand_chip *nand_chip)
{
        struct lpc32xx_nand_host *host = nand_get_controller_data(nand_chip);

        if ((readb(MLC_ISR(host->io_base)) &
             (MLCISR_CONTROLLER_READY | MLCISR_NAND_READY)) ==
            (MLCISR_CONTROLLER_READY | MLCISR_NAND_READY))
                return  1;

        return 0;
}

static irqreturn_t lpc3xxx_nand_irq(int irq, void *data)
{
        struct lpc32xx_nand_host *host = data;
        uint8_t sr;

        /* Clear interrupt flag by reading status */
        sr = readb(MLC_IRQ_SR(host->io_base));
        if (sr & MLCIRQ_NAND_READY)
                complete(&host->comp_nand);
        if (sr & MLCIRQ_CONTROLLER_READY)
                complete(&host->comp_controller);

        return IRQ_HANDLED;
}

static int lpc32xx_waitfunc_nand(struct nand_chip *chip)
{
        struct mtd_info *mtd = nand_to_mtd(chip);
        struct lpc32xx_nand_host *host = nand_get_controller_data(chip);

        if (readb(MLC_ISR(host->io_base)) & MLCISR_NAND_READY)
                goto exit;

        wait_for_completion(&host->comp_nand);

        while (!(readb(MLC_ISR(host->io_base)) & MLCISR_NAND_READY)) {
                /* Seems to be delayed sometimes by controller */
                dev_dbg(&mtd->dev, "Warning: NAND not ready.\n");
                cpu_relax();
        }

exit:
        return NAND_STATUS_READY;
}

static int lpc32xx_waitfunc_controller(struct nand_chip *chip)
{
        struct mtd_info *mtd = nand_to_mtd(chip);
        struct lpc32xx_nand_host *host = nand_get_controller_data(chip);

        if (readb(MLC_ISR(host->io_base)) & MLCISR_CONTROLLER_READY)
                goto exit;

        wait_for_completion(&host->comp_controller);

        while (!(readb(MLC_ISR(host->io_base)) &
                 MLCISR_CONTROLLER_READY)) {
                dev_dbg(&mtd->dev, "Warning: Controller not ready.\n");
                cpu_relax();
        }

exit:
        return NAND_STATUS_READY;
}

static int lpc32xx_waitfunc(struct nand_chip *chip)
{
        lpc32xx_waitfunc_nand(chip);
        lpc32xx_waitfunc_controller(chip);

        return NAND_STATUS_READY;
}

/*
 * Enable NAND write protect
 */
static void lpc32xx_wp_enable(struct lpc32xx_nand_host *host)
{
        if (host->wp_gpio)
                gpiod_set_value_cansleep(host->wp_gpio, 1);
}

/*
 * Disable NAND write protect
 */
static void lpc32xx_wp_disable(struct lpc32xx_nand_host *host)
{
        if (host->wp_gpio)
                gpiod_set_value_cansleep(host->wp_gpio, 0);
}

static void lpc32xx_dma_complete_func(void *completion)
{
        complete(completion);
}

static int lpc32xx_xmit_dma(struct mtd_info *mtd, void *mem, int len,
                            enum dma_transfer_direction dir)
{
        struct nand_chip *chip = mtd_to_nand(mtd);
        struct lpc32xx_nand_host *host = nand_get_controller_data(chip);
        struct dma_async_tx_descriptor *desc;
        int flags = DMA_CTRL_ACK | DMA_PREP_INTERRUPT;
        int res;

        sg_init_one(&host->sgl, mem, len);

        res = dma_map_sg(host->dma_chan->device->dev, &host->sgl, 1,
                         DMA_BIDIRECTIONAL);
        if (res != 1) {
                dev_err(mtd->dev.parent, "Failed to map sg list\n");
                return -ENXIO;
        }
        desc = dmaengine_prep_slave_sg(host->dma_chan, &host->sgl, 1, dir,
                                       flags);
        if (!desc) {
                dev_err(mtd->dev.parent, "Failed to prepare slave sg\n");
                goto out1;
        }

        init_completion(&host->comp_dma);
        desc->callback = lpc32xx_dma_complete_func;
        desc->callback_param = &host->comp_dma;

        dmaengine_submit(desc);
        dma_async_issue_pending(host->dma_chan);

        wait_for_completion_timeout(&host->comp_dma, msecs_to_jiffies(1000));

        dma_unmap_sg(host->dma_chan->device->dev, &host->sgl, 1,
                     DMA_BIDIRECTIONAL);
        return 0;
out1:
        dma_unmap_sg(host->dma_chan->device->dev, &host->sgl, 1,
                     DMA_BIDIRECTIONAL);
        return -ENXIO;
}

static int lpc32xx_read_page(struct nand_chip *chip, uint8_t *buf,
                             int oob_required, int page)
{
        struct mtd_info *mtd = nand_to_mtd(chip);
        struct lpc32xx_nand_host *host = nand_get_controller_data(chip);
        int i, j;
        uint8_t *oobbuf = chip->oob_poi;
        uint32_t mlc_isr;
        int res;
        uint8_t *dma_buf;
        bool dma_mapped;

        if ((void *)buf <= high_memory) {
                dma_buf = buf;
                dma_mapped = true;
        } else {
                dma_buf = host->dma_buf;
                dma_mapped = false;
        }

        /* Writing Command and Address */
        nand_read_page_op(chip, page, 0, NULL, 0);

        /* For all sub-pages */
        for (i = 0; i < host->mlcsubpages; i++) {
                /* Start Auto Decode Command */
                writeb(0x00, MLC_ECC_AUTO_DEC_REG(host->io_base));

                /* Wait for Controller Ready */
                lpc32xx_waitfunc_controller(chip);

                /* Check ECC Error status */
                mlc_isr = readl(MLC_ISR(host->io_base));
                if (mlc_isr & MLCISR_DECODER_FAILURE) {
                        mtd->ecc_stats.failed++;
                        dev_warn(&mtd->dev, "%s: DECODER_FAILURE\n", __func__);
                } else if (mlc_isr & MLCISR_ERRORS_DETECTED) {
                        mtd->ecc_stats.corrected += ((mlc_isr >> 4) & 0x3) + 1;
                }

                /* Read 512 + 16 Bytes */
                if (use_dma) {
                        res = lpc32xx_xmit_dma(mtd, dma_buf + i * 512, 512,
                                               DMA_DEV_TO_MEM);
                        if (res)
                                return res;
                } else {
                        for (j = 0; j < (512 >> 2); j++) {
                                *((uint32_t *)(buf)) =
                                        readl(MLC_BUFF(host->io_base));
                                buf += 4;
                        }
                }
                for (j = 0; j < (16 >> 2); j++) {
                        *((uint32_t *)(oobbuf)) =
                                readl(MLC_BUFF(host->io_base));
                        oobbuf += 4;
                }
        }

        if (use_dma && !dma_mapped)
                memcpy(buf, dma_buf, mtd->writesize);

        return 0;
}

static int lpc32xx_write_page_lowlevel(struct nand_chip *chip,
                                       const uint8_t *buf, int oob_required,
                                       int page)
{
        struct mtd_info *mtd = nand_to_mtd(chip);
        struct lpc32xx_nand_host *host = nand_get_controller_data(chip);
        const uint8_t *oobbuf = chip->oob_poi;
        uint8_t *dma_buf = (uint8_t *)buf;
        int res;
        int i, j;

        if (use_dma && (void *)buf >= high_memory) {
                dma_buf = host->dma_buf;
                memcpy(dma_buf, buf, mtd->writesize);
        }

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

        for (i = 0; i < host->mlcsubpages; i++) {
                /* Start Encode */
                writeb(0x00, MLC_ECC_ENC_REG(host->io_base));

                /* Write 512 + 6 Bytes to Buffer */
                if (use_dma) {
                        res = lpc32xx_xmit_dma(mtd, dma_buf + i * 512, 512,
                                               DMA_MEM_TO_DEV);
                        if (res)
                                return res;
                } else {
                        for (j = 0; j < (512 >> 2); j++) {
                                writel(*((uint32_t *)(buf)),
                                       MLC_BUFF(host->io_base));
                                buf += 4;
                        }
                }
                writel(*((uint32_t *)(oobbuf)), MLC_BUFF(host->io_base));
                oobbuf += 4;
                writew(*((uint16_t *)(oobbuf)), MLC_BUFF(host->io_base));
                oobbuf += 12;

                /* Auto Encode w/ Bit 8 = 0 (see LPC MLC Controller manual) */
                writeb(0x00, MLC_ECC_AUTO_ENC_REG(host->io_base));

                /* Wait for Controller Ready */
                lpc32xx_waitfunc_controller(chip);
        }

        return nand_prog_page_end_op(chip);
}

static int lpc32xx_read_oob(struct nand_chip *chip, int page)
{
        struct lpc32xx_nand_host *host = nand_get_controller_data(chip);

        /* Read whole page - necessary with MLC controller! */
        lpc32xx_read_page(chip, host->dummy_buf, 1, page);

        return 0;
}

static int lpc32xx_write_oob(struct nand_chip *chip, int page)
{
        /* None, write_oob conflicts with the automatic LPC MLC ECC decoder! */
        return 0;
}

/* Prepares MLC for transfers with H/W ECC enabled: always enabled anyway */
static void lpc32xx_ecc_enable(struct nand_chip *chip, int mode)
{
        /* Always enabled! */
}

static int lpc32xx_dma_setup(struct lpc32xx_nand_host *host)
{
        struct mtd_info *mtd = nand_to_mtd(&host->nand_chip);
        dma_cap_mask_t mask;

        host->dma_chan = dma_request_chan(mtd->dev.parent, "rx-tx");
        if (IS_ERR(host->dma_chan)) {
                /* fallback to request using platform data */
                if (!host->pdata || !host->pdata->dma_filter) {
                        dev_err(mtd->dev.parent, "no DMA platform data\n");
                        return -ENOENT;
                }

                dma_cap_zero(mask);
                dma_cap_set(DMA_SLAVE, mask);
                host->dma_chan = dma_request_channel(mask, host->pdata->dma_filter, "nand-mlc");

                if (!host->dma_chan) {
                        dev_err(mtd->dev.parent, "Failed to request DMA channel\n");
                        return -EBUSY;
                }
        }

        /*
         * Set direction to a sensible value even if the dmaengine driver
         * should ignore it. With the default (DMA_MEM_TO_MEM), the amba-pl08x
         * driver criticizes it as "alien transfer direction".
         */
        host->dma_slave_config.direction = DMA_DEV_TO_MEM;
        host->dma_slave_config.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
        host->dma_slave_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
        host->dma_slave_config.src_maxburst = 128;
        host->dma_slave_config.dst_maxburst = 128;
        /* DMA controller does flow control: */
        host->dma_slave_config.device_fc = false;
        host->dma_slave_config.src_addr = MLC_BUFF(host->io_base_phy);
        host->dma_slave_config.dst_addr = MLC_BUFF(host->io_base_phy);
        if (dmaengine_slave_config(host->dma_chan, &host->dma_slave_config)) {
                dev_err(mtd->dev.parent, "Failed to setup DMA slave\n");
                goto out1;
        }

        return 0;
out1:
        dma_release_channel(host->dma_chan);
        return -ENXIO;
}

static struct lpc32xx_nand_cfg_mlc *lpc32xx_parse_dt(struct device *dev)
{
        struct lpc32xx_nand_cfg_mlc *ncfg;
        struct device_node *np = dev->of_node;

        ncfg = devm_kzalloc(dev, sizeof(*ncfg), GFP_KERNEL);
        if (!ncfg)
                return NULL;

        of_property_read_u32(np, "nxp,tcea-delay", &ncfg->tcea_delay);
        of_property_read_u32(np, "nxp,busy-delay", &ncfg->busy_delay);
        of_property_read_u32(np, "nxp,nand-ta", &ncfg->nand_ta);
        of_property_read_u32(np, "nxp,rd-high", &ncfg->rd_high);
        of_property_read_u32(np, "nxp,rd-low", &ncfg->rd_low);
        of_property_read_u32(np, "nxp,wr-high", &ncfg->wr_high);
        of_property_read_u32(np, "nxp,wr-low", &ncfg->wr_low);

        if (!ncfg->tcea_delay || !ncfg->busy_delay || !ncfg->nand_ta ||
            !ncfg->rd_high || !ncfg->rd_low || !ncfg->wr_high ||
            !ncfg->wr_low) {
                dev_err(dev, "chip parameters not specified correctly\n");
                return NULL;
        }

        return ncfg;
}

static int lpc32xx_nand_attach_chip(struct nand_chip *chip)
{
        struct mtd_info *mtd = nand_to_mtd(chip);
        struct lpc32xx_nand_host *host = nand_get_controller_data(chip);
        struct device *dev = &host->pdev->dev;

        if (chip->ecc.engine_type != NAND_ECC_ENGINE_TYPE_ON_HOST)
                return 0;

        host->dma_buf = devm_kzalloc(dev, mtd->writesize, GFP_KERNEL);
        if (!host->dma_buf)
                return -ENOMEM;

        host->dummy_buf = devm_kzalloc(dev, mtd->writesize, GFP_KERNEL);
        if (!host->dummy_buf)
                return -ENOMEM;

        chip->ecc.size = 512;
        chip->ecc.hwctl = lpc32xx_ecc_enable;
        chip->ecc.read_page_raw = lpc32xx_read_page;
        chip->ecc.read_page = lpc32xx_read_page;
        chip->ecc.write_page_raw = lpc32xx_write_page_lowlevel;
        chip->ecc.write_page = lpc32xx_write_page_lowlevel;
        chip->ecc.write_oob = lpc32xx_write_oob;
        chip->ecc.read_oob = lpc32xx_read_oob;
        chip->ecc.strength = 4;
        chip->ecc.bytes = 10;

        mtd_set_ooblayout(mtd, &lpc32xx_ooblayout_ops);
        host->mlcsubpages = mtd->writesize / 512;

        return 0;
}

static const struct nand_controller_ops lpc32xx_nand_controller_ops = {
        .attach_chip = lpc32xx_nand_attach_chip,
};

/*
 * Probe for NAND controller
 */
static int lpc32xx_nand_probe(struct platform_device *pdev)
{
        struct lpc32xx_nand_host *host;
        struct mtd_info *mtd;
        struct nand_chip *nand_chip;
        struct resource *rc;
        int res;

        /* Allocate memory for the device structure (and zero it) */
        host = devm_kzalloc(&pdev->dev, sizeof(*host), GFP_KERNEL);
        if (!host)
                return -ENOMEM;

        host->pdev = pdev;

        host->io_base = devm_platform_get_and_ioremap_resource(pdev, 0, &rc);
        if (IS_ERR(host->io_base))
                return PTR_ERR(host->io_base);

        host->io_base_phy = rc->start;

        nand_chip = &host->nand_chip;
        mtd = nand_to_mtd(nand_chip);
        if (pdev->dev.of_node)
                host->ncfg = lpc32xx_parse_dt(&pdev->dev);
        if (!host->ncfg) {
                dev_err(&pdev->dev,
                        "Missing or bad NAND config from device tree\n");
                return -ENOENT;
        }

        /* Start with WP disabled, if available */
        host->wp_gpio = gpiod_get_optional(&pdev->dev, NULL, GPIOD_OUT_LOW);
        res = PTR_ERR_OR_ZERO(host->wp_gpio);
        if (res) {
                if (res != -EPROBE_DEFER)
                        dev_err(&pdev->dev, "WP GPIO is not available: %d\n",
                                res);
                return res;
        }

        gpiod_set_consumer_name(host->wp_gpio, "NAND WP");

        host->pdata = dev_get_platdata(&pdev->dev);

        /* link the private data structures */
        nand_set_controller_data(nand_chip, host);
        nand_set_flash_node(nand_chip, pdev->dev.of_node);
        mtd->dev.parent = &pdev->dev;

        /* Get NAND clock */
        host->clk = clk_get(&pdev->dev, NULL);
        if (IS_ERR(host->clk)) {
                dev_err(&pdev->dev, "Clock initialization failure\n");
                res = -ENOENT;
                goto free_gpio;
        }
        res = clk_prepare_enable(host->clk);
        if (res)
                goto put_clk;

        nand_chip->legacy.cmd_ctrl = lpc32xx_nand_cmd_ctrl;
        nand_chip->legacy.dev_ready = lpc32xx_nand_device_ready;
        nand_chip->legacy.chip_delay = 25; /* us */
        nand_chip->legacy.IO_ADDR_R = MLC_DATA(host->io_base);
        nand_chip->legacy.IO_ADDR_W = MLC_DATA(host->io_base);

        /* Init NAND controller */
        lpc32xx_nand_setup(host);

        platform_set_drvdata(pdev, host);

        /* Initialize function pointers */
        nand_chip->legacy.waitfunc = lpc32xx_waitfunc;

        nand_chip->options = NAND_NO_SUBPAGE_WRITE;
        nand_chip->bbt_options = NAND_BBT_USE_FLASH | NAND_BBT_NO_OOB;
        nand_chip->bbt_td = &lpc32xx_nand_bbt;
        nand_chip->bbt_md = &lpc32xx_nand_bbt_mirror;

        if (use_dma) {
                res = lpc32xx_dma_setup(host);
                if (res) {
                        res = -EIO;
                        goto unprepare_clk;
                }
        }

        /* initially clear interrupt status */
        readb(MLC_IRQ_SR(host->io_base));

        init_completion(&host->comp_nand);
        init_completion(&host->comp_controller);

        host->irq = platform_get_irq(pdev, 0);
        if (host->irq < 0) {
                res = -EINVAL;
                goto release_dma_chan;
        }

        if (request_irq(host->irq, &lpc3xxx_nand_irq,
                        IRQF_TRIGGER_HIGH, DRV_NAME, host)) {
                dev_err(&pdev->dev, "Error requesting NAND IRQ\n");
                res = -ENXIO;
                goto release_dma_chan;
        }

        /*
         * Scan to find existence of the device and get the type of NAND device:
         * SMALL block or LARGE block.
         */
        nand_chip->legacy.dummy_controller.ops = &lpc32xx_nand_controller_ops;
        res = nand_scan(nand_chip, 1);
        if (res)
                goto free_irq;

        mtd->name = DRV_NAME;

        res = mtd_device_register(mtd, host->ncfg->parts,
                                  host->ncfg->num_parts);
        if (res)
                goto cleanup_nand;

        return 0;

cleanup_nand:
        nand_cleanup(nand_chip);
free_irq:
        free_irq(host->irq, host);
release_dma_chan:
        if (use_dma)
                dma_release_channel(host->dma_chan);
unprepare_clk:
        clk_disable_unprepare(host->clk);
put_clk:
        clk_put(host->clk);
free_gpio:
        lpc32xx_wp_enable(host);
        gpiod_put(host->wp_gpio);

        return res;
}

/*
 * Remove NAND device
 */
static void lpc32xx_nand_remove(struct platform_device *pdev)
{
        struct lpc32xx_nand_host *host = platform_get_drvdata(pdev);
        struct nand_chip *chip = &host->nand_chip;
        int ret;

        ret = mtd_device_unregister(nand_to_mtd(chip));
        WARN_ON(ret);
        nand_cleanup(chip);

        free_irq(host->irq, host);
        if (use_dma)
                dma_release_channel(host->dma_chan);

        clk_disable_unprepare(host->clk);
        clk_put(host->clk);

        lpc32xx_wp_enable(host);
        gpiod_put(host->wp_gpio);
}

static int lpc32xx_nand_resume(struct platform_device *pdev)
{
        struct lpc32xx_nand_host *host = platform_get_drvdata(pdev);
        int ret;

        /* Re-enable NAND clock */
        ret = clk_prepare_enable(host->clk);
        if (ret)
                return ret;

        /* Fresh init of NAND controller */
        lpc32xx_nand_setup(host);

        /* Disable write protect */
        lpc32xx_wp_disable(host);

        return 0;
}

static int lpc32xx_nand_suspend(struct platform_device *pdev, pm_message_t pm)
{
        struct lpc32xx_nand_host *host = platform_get_drvdata(pdev);

        /* Enable write protect for safety */
        lpc32xx_wp_enable(host);

        /* Disable clock */
        clk_disable_unprepare(host->clk);
        return 0;
}

static const struct of_device_id lpc32xx_nand_match[] = {
        { .compatible = "nxp,lpc3220-mlc" },
        { /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, lpc32xx_nand_match);

static struct platform_driver lpc32xx_nand_driver = {
        .probe          = lpc32xx_nand_probe,
        .remove         = lpc32xx_nand_remove,
        .resume         = pm_ptr(lpc32xx_nand_resume),
        .suspend        = pm_ptr(lpc32xx_nand_suspend),
        .driver         = {
                .name   = DRV_NAME,
                .of_match_table = lpc32xx_nand_match,
        },
};

module_platform_driver(lpc32xx_nand_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
MODULE_DESCRIPTION("NAND driver for the NXP LPC32XX MLC controller");