// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * NXP LPC32XX NAND SLC driver
 *
 * Authors:
 *    Kevin Wells <kevin.wells@nxp.com>
 *    Roland Stigge <stigge@antcom.de>
 *
 * Copyright © 2011 NXP Semiconductors
 * Copyright © 2012 Roland Stigge
 */

#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/io.h>
#include <linux/mm.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/gpio/consumer.h>
#include <linux/of.h>
#include <linux/mtd/lpc32xx_slc.h>

#define LPC32XX_MODNAME         "lpc32xx-nand"

/**********************************************************************
* SLC NAND controller register offsets
**********************************************************************/

#define SLC_DATA(x)             (x + 0x000)
#define SLC_ADDR(x)             (x + 0x004)
#define SLC_CMD(x)              (x + 0x008)
#define SLC_STOP(x)             (x + 0x00C)
#define SLC_CTRL(x)             (x + 0x010)
#define SLC_CFG(x)              (x + 0x014)
#define SLC_STAT(x)             (x + 0x018)
#define SLC_INT_STAT(x)         (x + 0x01C)
#define SLC_IEN(x)              (x + 0x020)
#define SLC_ISR(x)              (x + 0x024)
#define SLC_ICR(x)              (x + 0x028)
#define SLC_TAC(x)              (x + 0x02C)
#define SLC_TC(x)               (x + 0x030)
#define SLC_ECC(x)              (x + 0x034)
#define SLC_DMA_DATA(x)         (x + 0x038)

/**********************************************************************
* slc_ctrl register definitions
**********************************************************************/
#define SLCCTRL_SW_RESET        (1 << 2) /* Reset the NAND controller bit */
#define SLCCTRL_ECC_CLEAR       (1 << 1) /* Reset ECC bit */
#define SLCCTRL_DMA_START       (1 << 0) /* Start DMA channel bit */

/**********************************************************************
* slc_cfg register definitions
**********************************************************************/
#define SLCCFG_CE_LOW           (1 << 5) /* Force CE low bit */
#define SLCCFG_DMA_ECC          (1 << 4) /* Enable DMA ECC bit */
#define SLCCFG_ECC_EN           (1 << 3) /* ECC enable bit */
#define SLCCFG_DMA_BURST        (1 << 2) /* DMA burst bit */
#define SLCCFG_DMA_DIR          (1 << 1) /* DMA write(0)/read(1) bit */
#define SLCCFG_WIDTH            (1 << 0) /* External device width, 0=8bit */

/**********************************************************************
* slc_stat register definitions
**********************************************************************/
#define SLCSTAT_DMA_FIFO        (1 << 2) /* DMA FIFO has data bit */
#define SLCSTAT_SLC_FIFO        (1 << 1) /* SLC FIFO has data bit */
#define SLCSTAT_NAND_READY      (1 << 0) /* NAND device is ready bit */

/**********************************************************************
* slc_int_stat, slc_ien, slc_isr, and slc_icr register definitions
**********************************************************************/
#define SLCSTAT_INT_TC          (1 << 1) /* Transfer count bit */
#define SLCSTAT_INT_RDY_EN      (1 << 0) /* Ready interrupt bit */

/**********************************************************************
* slc_tac register definitions
**********************************************************************/
/* Computation of clock cycles on basis of controller and device clock rates */
#define SLCTAC_CLOCKS(c, n, s)  (min_t(u32, DIV_ROUND_UP(c, n) - 1, 0xF) << s)

/* Clock setting for RDY write sample wait time in 2*n clocks */
#define SLCTAC_WDR(n)           (((n) & 0xF) << 28)
/* Write pulse width in clock cycles, 1 to 16 clocks */
#define SLCTAC_WWIDTH(c, n)     (SLCTAC_CLOCKS(c, n, 24))
/* Write hold time of control and data signals, 1 to 16 clocks */
#define SLCTAC_WHOLD(c, n)      (SLCTAC_CLOCKS(c, n, 20))
/* Write setup time of control and data signals, 1 to 16 clocks */
#define SLCTAC_WSETUP(c, n)     (SLCTAC_CLOCKS(c, n, 16))
/* Clock setting for RDY read sample wait time in 2*n clocks */
#define SLCTAC_RDR(n)           (((n) & 0xF) << 12)
/* Read pulse width in clock cycles, 1 to 16 clocks */
#define SLCTAC_RWIDTH(c, n)     (SLCTAC_CLOCKS(c, n, 8))
/* Read hold time of control and data signals, 1 to 16 clocks */
#define SLCTAC_RHOLD(c, n)      (SLCTAC_CLOCKS(c, n, 4))
/* Read setup time of control and data signals, 1 to 16 clocks */
#define SLCTAC_RSETUP(c, n)     (SLCTAC_CLOCKS(c, n, 0))

/**********************************************************************
* slc_ecc register definitions
**********************************************************************/
/* ECC line party fetch macro */
#define SLCECC_TO_LINEPAR(n)    (((n) >> 6) & 0x7FFF)
#define SLCECC_TO_COLPAR(n)     ((n) & 0x3F)

/*
 * DMA requires storage space for the DMA local buffer and the hardware ECC
 * storage area. The DMA local buffer is only used if DMA mapping fails
 * during runtime.
 */
#define LPC32XX_DMA_DATA_SIZE           4096
#define LPC32XX_ECC_SAVE_SIZE           ((4096 / 256) * 4)

/* Number of bytes used for ECC stored in NAND per 256 bytes */
#define LPC32XX_SLC_DEV_ECC_BYTES       3

/*
 * If the NAND base clock frequency can't be fetched, this frequency will be
 * used instead as the base. This rate is used to setup the timing registers
 * used for NAND accesses.
 */
#define LPC32XX_DEF_BUS_RATE            133250000

/* Milliseconds for DMA FIFO timeout (unlikely anyway) */
#define LPC32XX_DMA_TIMEOUT             100

/*
 * NAND ECC Layout for small page NAND devices
 * Note: For large and huge page devices, the default layouts are used
 */
static int lpc32xx_ooblayout_ecc(struct mtd_info *mtd, int section,
                                 struct mtd_oob_region *oobregion)
{
        if (section)
                return -ERANGE;

        oobregion->length = 6;
        oobregion->offset = 10;

        return 0;
}

static int lpc32xx_ooblayout_free(struct mtd_info *mtd, int section,
                                  struct mtd_oob_region *oobregion)
{
        if (section > 1)
                return -ERANGE;

        if (!section) {
                oobregion->offset = 0;
                oobregion->length = 4;
        } else {
                oobregion->offset = 6;
                oobregion->length = 4;
        }

        return 0;
}

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

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

/*
 * Small page FLASH BBT descriptors, marker at offset 0, version at offset 6
 * Note: Large page devices used the default layout
 */
static struct nand_bbt_descr bbt_smallpage_main_descr = {
        .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
                | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
        .offs = 0,
        .len = 4,
        .veroffs = 6,
        .maxblocks = 4,
        .pattern = bbt_pattern
};

static struct nand_bbt_descr bbt_smallpage_mirror_descr = {
        .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
                | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
        .offs = 0,
        .len = 4,
        .veroffs = 6,
        .maxblocks = 4,
        .pattern = mirror_pattern
};

/*
 * NAND platform configuration structure
 */
struct lpc32xx_nand_cfg_slc {
        uint32_t wdr_clks;
        uint32_t wwidth;
        uint32_t whold;
        uint32_t wsetup;
        uint32_t rdr_clks;
        uint32_t rwidth;
        uint32_t rhold;
        uint32_t rsetup;
        struct mtd_partition *parts;
        unsigned num_parts;
};

struct lpc32xx_nand_host {
        struct nand_chip        nand_chip;
        struct lpc32xx_slc_platform_data *pdata;
        struct clk              *clk;
        struct gpio_desc        *wp_gpio;
        void __iomem            *io_base;
        struct lpc32xx_nand_cfg_slc *ncfg;

        struct completion       comp;
        struct dma_chan         *dma_chan;
        uint32_t                dma_buf_len;
        struct dma_slave_config dma_slave_config;
        struct scatterlist      sgl;

        /*
         * DMA and CPU addresses of ECC work area and data buffer
         */
        uint32_t                *ecc_buf;
        uint8_t                 *data_buf;
        dma_addr_t              io_base_dma;
};

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

        /* Reset SLC controller */
        writel(SLCCTRL_SW_RESET, SLC_CTRL(host->io_base));
        udelay(1000);

        /* Basic setup */
        writel(0, SLC_CFG(host->io_base));
        writel(0, SLC_IEN(host->io_base));
        writel((SLCSTAT_INT_TC | SLCSTAT_INT_RDY_EN),
                SLC_ICR(host->io_base));

        /* Get base clock for SLC block */
        clkrate = clk_get_rate(host->clk);
        if (clkrate == 0)
                clkrate = LPC32XX_DEF_BUS_RATE;

        /* Compute clock setup values */
        tmp = SLCTAC_WDR(host->ncfg->wdr_clks) |
                SLCTAC_WWIDTH(clkrate, host->ncfg->wwidth) |
                SLCTAC_WHOLD(clkrate, host->ncfg->whold) |
                SLCTAC_WSETUP(clkrate, host->ncfg->wsetup) |
                SLCTAC_RDR(host->ncfg->rdr_clks) |
                SLCTAC_RWIDTH(clkrate, host->ncfg->rwidth) |
                SLCTAC_RHOLD(clkrate, host->ncfg->rhold) |
                SLCTAC_RSETUP(clkrate, host->ncfg->rsetup);
        writel(tmp, SLC_TAC(host->io_base));
}

/*
 * Hardware specific access to control lines
 */
static void lpc32xx_nand_cmd_ctrl(struct nand_chip *chip, int cmd,
                                  unsigned int ctrl)
{
        uint32_t tmp;
        struct lpc32xx_nand_host *host = nand_get_controller_data(chip);

        /* Does CE state need to be changed? */
        tmp = readl(SLC_CFG(host->io_base));
        if (ctrl & NAND_NCE)
                tmp |= SLCCFG_CE_LOW;
        else
                tmp &= ~SLCCFG_CE_LOW;
        writel(tmp, SLC_CFG(host->io_base));

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

/*
 * Read the Device Ready pin
 */
static int lpc32xx_nand_device_ready(struct nand_chip *chip)
{
        struct lpc32xx_nand_host *host = nand_get_controller_data(chip);
        int rdy = 0;

        if ((readl(SLC_STAT(host->io_base)) & SLCSTAT_NAND_READY) != 0)
                rdy = 1;

        return rdy;
}

/*
 * 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);
}

/*
 * Prepares SLC for transfers with H/W ECC enabled
 */
static void lpc32xx_nand_ecc_enable(struct nand_chip *chip, int mode)
{
        /* Hardware ECC is enabled automatically in hardware as needed */
}

/*
 * Calculates the ECC for the data
 */
static int lpc32xx_nand_ecc_calculate(struct nand_chip *chip,
                                      const unsigned char *buf,
                                      unsigned char *code)
{
        /*
         * ECC is calculated automatically in hardware during syndrome read
         * and write operations, so it doesn't need to be calculated here.
         */
        return 0;
}

/*
 * Read a single byte from NAND device
 */
static uint8_t lpc32xx_nand_read_byte(struct nand_chip *chip)
{
        struct lpc32xx_nand_host *host = nand_get_controller_data(chip);

        return (uint8_t)readl(SLC_DATA(host->io_base));
}

/*
 * Simple device read without ECC
 */
static void lpc32xx_nand_read_buf(struct nand_chip *chip, u_char *buf, int len)
{
        struct lpc32xx_nand_host *host = nand_get_controller_data(chip);

        /* Direct device read with no ECC */
        while (len-- > 0)
                *buf++ = (uint8_t)readl(SLC_DATA(host->io_base));
}

/*
 * Simple device write without ECC
 */
static void lpc32xx_nand_write_buf(struct nand_chip *chip, const uint8_t *buf,
                                   int len)
{
        struct lpc32xx_nand_host *host = nand_get_controller_data(chip);

        /* Direct device write with no ECC */
        while (len-- > 0)
                writel((uint32_t)*buf++, SLC_DATA(host->io_base));
}

/*
 * Read the OOB data from the device without ECC using FIFO method
 */
static int lpc32xx_nand_read_oob_syndrome(struct nand_chip *chip, int page)
{
        struct mtd_info *mtd = nand_to_mtd(chip);

        return nand_read_oob_op(chip, page, 0, chip->oob_poi, mtd->oobsize);
}

/*
 * Write the OOB data to the device without ECC using FIFO method
 */
static int lpc32xx_nand_write_oob_syndrome(struct nand_chip *chip, int page)
{
        struct mtd_info *mtd = nand_to_mtd(chip);

        return nand_prog_page_op(chip, page, mtd->writesize, chip->oob_poi,
                                 mtd->oobsize);
}

/*
 * Fills in the ECC fields in the OOB buffer with the hardware generated ECC
 */
static void lpc32xx_slc_ecc_copy(uint8_t *spare, const uint32_t *ecc, int count)
{
        int i;

        for (i = 0; i < (count * 3); i += 3) {
                uint32_t ce = ecc[i / 3];
                ce = ~(ce << 2) & 0xFFFFFF;
                spare[i + 2] = (uint8_t)(ce & 0xFF);
                ce >>= 8;
                spare[i + 1] = (uint8_t)(ce & 0xFF);
                ce >>= 8;
                spare[i] = (uint8_t)(ce & 0xFF);
        }
}

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

static int lpc32xx_xmit_dma(struct mtd_info *mtd, dma_addr_t dma,
                            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;

        host->dma_slave_config.direction = dir;
        host->dma_slave_config.src_addr = dma;
        host->dma_slave_config.dst_addr = dma;
        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 = 4;
        host->dma_slave_config.dst_maxburst = 4;
        /* DMA controller does flow control: */
        host->dma_slave_config.device_fc = false;
        if (dmaengine_slave_config(host->dma_chan, &host->dma_slave_config)) {
                dev_err(mtd->dev.parent, "Failed to setup DMA slave\n");
                return -ENXIO;
        }

        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);
        desc->callback = lpc32xx_dma_complete_func;
        desc->callback_param = &host->comp;

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

        wait_for_completion_timeout(&host->comp, 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;
}

/*
 * DMA read/write transfers with ECC support
 */
static int lpc32xx_xfer(struct mtd_info *mtd, uint8_t *buf, int eccsubpages,
                        int read)
{
        struct nand_chip *chip = mtd_to_nand(mtd);
        struct lpc32xx_nand_host *host = nand_get_controller_data(chip);
        int i, status = 0;
        unsigned long timeout;
        int res;
        enum dma_transfer_direction dir =
                read ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV;
        uint8_t *dma_buf;
        bool dma_mapped;

        if ((void *)buf <= high_memory) {
                dma_buf = buf;
                dma_mapped = true;
        } else {
                dma_buf = host->data_buf;
                dma_mapped = false;
                if (!read)
                        memcpy(host->data_buf, buf, mtd->writesize);
        }

        if (read) {
                writel(readl(SLC_CFG(host->io_base)) |
                       SLCCFG_DMA_DIR | SLCCFG_ECC_EN | SLCCFG_DMA_ECC |
                       SLCCFG_DMA_BURST, SLC_CFG(host->io_base));
        } else {
                writel((readl(SLC_CFG(host->io_base)) |
                        SLCCFG_ECC_EN | SLCCFG_DMA_ECC | SLCCFG_DMA_BURST) &
                       ~SLCCFG_DMA_DIR,
                        SLC_CFG(host->io_base));
        }

        /* Clear initial ECC */
        writel(SLCCTRL_ECC_CLEAR, SLC_CTRL(host->io_base));

        /* Transfer size is data area only */
        writel(mtd->writesize, SLC_TC(host->io_base));

        /* Start transfer in the NAND controller */
        writel(readl(SLC_CTRL(host->io_base)) | SLCCTRL_DMA_START,
               SLC_CTRL(host->io_base));

        for (i = 0; i < chip->ecc.steps; i++) {
                /* Data */
                res = lpc32xx_xmit_dma(mtd, SLC_DMA_DATA(host->io_base_dma),
                                       dma_buf + i * chip->ecc.size,
                                       mtd->writesize / chip->ecc.steps, dir);
                if (res)
                        return res;

                /* Always _read_ ECC */
                if (i == chip->ecc.steps - 1)
                        break;
                if (!read) /* ECC availability delayed on write */
                        udelay(10);
                res = lpc32xx_xmit_dma(mtd, SLC_ECC(host->io_base_dma),
                                       &host->ecc_buf[i], 4, DMA_DEV_TO_MEM);
                if (res)
                        return res;
        }

        /*
         * According to NXP, the DMA can be finished here, but the NAND
         * controller may still have buffered data. After porting to using the
         * dmaengine DMA driver (amba-pl080), the condition (DMA_FIFO empty)
         * appears to be always true, according to tests. Keeping the check for
         * safety reasons for now.
         */
        if (readl(SLC_STAT(host->io_base)) & SLCSTAT_DMA_FIFO) {
                dev_warn(mtd->dev.parent, "FIFO not empty!\n");
                timeout = jiffies + msecs_to_jiffies(LPC32XX_DMA_TIMEOUT);
                while ((readl(SLC_STAT(host->io_base)) & SLCSTAT_DMA_FIFO) &&
                       time_before(jiffies, timeout))
                        cpu_relax();
                if (!time_before(jiffies, timeout)) {
                        dev_err(mtd->dev.parent, "FIFO held data too long\n");
                        status = -EIO;
                }
        }

        /* Read last calculated ECC value */
        if (!read)
                udelay(10);
        host->ecc_buf[chip->ecc.steps - 1] =
                readl(SLC_ECC(host->io_base));

        /* Flush DMA */
        dmaengine_terminate_all(host->dma_chan);

        if (readl(SLC_STAT(host->io_base)) & SLCSTAT_DMA_FIFO ||
            readl(SLC_TC(host->io_base))) {
                /* Something is left in the FIFO, something is wrong */
                dev_err(mtd->dev.parent, "DMA FIFO failure\n");
                status = -EIO;
        }

        /* Stop DMA & HW ECC */
        writel(readl(SLC_CTRL(host->io_base)) & ~SLCCTRL_DMA_START,
               SLC_CTRL(host->io_base));
        writel(readl(SLC_CFG(host->io_base)) &
               ~(SLCCFG_DMA_DIR | SLCCFG_ECC_EN | SLCCFG_DMA_ECC |
                 SLCCFG_DMA_BURST), SLC_CFG(host->io_base));

        if (!dma_mapped && read)
                memcpy(buf, host->data_buf, mtd->writesize);

        return status;
}

/*
 * Read the data and OOB data from the device, use ECC correction with the
 * data, disable ECC for the OOB data
 */
static int lpc32xx_nand_read_page_syndrome(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);
        struct mtd_oob_region oobregion = { };
        int stat, i, status, error;
        uint8_t *oobecc, tmpecc[LPC32XX_ECC_SAVE_SIZE];

        /* Issue read command */
        nand_read_page_op(chip, page, 0, NULL, 0);

        /* Read data and oob, calculate ECC */
        status = lpc32xx_xfer(mtd, buf, chip->ecc.steps, 1);

        /* Get OOB data */
        chip->legacy.read_buf(chip, chip->oob_poi, mtd->oobsize);

        /* Convert to stored ECC format */
        lpc32xx_slc_ecc_copy(tmpecc, (uint32_t *) host->ecc_buf, chip->ecc.steps);

        /* Pointer to ECC data retrieved from NAND spare area */
        error = mtd_ooblayout_ecc(mtd, 0, &oobregion);
        if (error)
                return error;

        oobecc = chip->oob_poi + oobregion.offset;

        for (i = 0; i < chip->ecc.steps; i++) {
                stat = chip->ecc.correct(chip, buf, oobecc,
                                         &tmpecc[i * chip->ecc.bytes]);
                if (stat < 0)
                        mtd->ecc_stats.failed++;
                else
                        mtd->ecc_stats.corrected += stat;

                buf += chip->ecc.size;
                oobecc += chip->ecc.bytes;
        }

        return status;
}

/*
 * Read the data and OOB data from the device, no ECC correction with the
 * data or OOB data
 */
static int lpc32xx_nand_read_page_raw_syndrome(struct nand_chip *chip,
                                               uint8_t *buf, int oob_required,
                                               int page)
{
        struct mtd_info *mtd = nand_to_mtd(chip);

        /* Issue read command */
        nand_read_page_op(chip, page, 0, NULL, 0);

        /* Raw reads can just use the FIFO interface */
        chip->legacy.read_buf(chip, buf, chip->ecc.size * chip->ecc.steps);
        chip->legacy.read_buf(chip, chip->oob_poi, mtd->oobsize);

        return 0;
}

/*
 * Write the data and OOB data to the device, use ECC with the data,
 * disable ECC for the OOB data
 */
static int lpc32xx_nand_write_page_syndrome(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);
        struct mtd_oob_region oobregion = { };
        uint8_t *pb;
        int error;

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

        /* Write data, calculate ECC on outbound data */
        error = lpc32xx_xfer(mtd, (uint8_t *)buf, chip->ecc.steps, 0);
        if (error)
                return error;

        /*
         * The calculated ECC needs some manual work done to it before
         * committing it to NAND. Process the calculated ECC and place
         * the resultant values directly into the OOB buffer. */
        error = mtd_ooblayout_ecc(mtd, 0, &oobregion);
        if (error)
                return error;

        pb = chip->oob_poi + oobregion.offset;
        lpc32xx_slc_ecc_copy(pb, (uint32_t *)host->ecc_buf, chip->ecc.steps);

        /* Write ECC data to device */
        chip->legacy.write_buf(chip, chip->oob_poi, mtd->oobsize);

        return nand_prog_page_end_op(chip);
}

/*
 * Write the data and OOB data to the device, no ECC correction with the
 * data or OOB data
 */
static int lpc32xx_nand_write_page_raw_syndrome(struct nand_chip *chip,
                                                const uint8_t *buf,
                                                int oob_required, int page)
{
        struct mtd_info *mtd = nand_to_mtd(chip);

        /* Raw writes can just use the FIFO interface */
        nand_prog_page_begin_op(chip, page, 0, buf,
                                chip->ecc.size * chip->ecc.steps);
        chip->legacy.write_buf(chip, chip->oob_poi, mtd->oobsize);

        return nand_prog_page_end_op(chip);
}

static int lpc32xx_nand_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-slc");

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

        return 0;
}

static struct lpc32xx_nand_cfg_slc *lpc32xx_parse_dt(struct device *dev)
{
        struct lpc32xx_nand_cfg_slc *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,wdr-clks", &ncfg->wdr_clks);
        of_property_read_u32(np, "nxp,wwidth", &ncfg->wwidth);
        of_property_read_u32(np, "nxp,whold", &ncfg->whold);
        of_property_read_u32(np, "nxp,wsetup", &ncfg->wsetup);
        of_property_read_u32(np, "nxp,rdr-clks", &ncfg->rdr_clks);
        of_property_read_u32(np, "nxp,rwidth", &ncfg->rwidth);
        of_property_read_u32(np, "nxp,rhold", &ncfg->rhold);
        of_property_read_u32(np, "nxp,rsetup", &ncfg->rsetup);

        if (!ncfg->wdr_clks || !ncfg->wwidth || !ncfg->whold ||
            !ncfg->wsetup || !ncfg->rdr_clks || !ncfg->rwidth ||
            !ncfg->rhold || !ncfg->rsetup) {
                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);

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

        /* OOB and ECC CPU and DMA work areas */
        host->ecc_buf = (uint32_t *)(host->data_buf + LPC32XX_DMA_DATA_SIZE);

        /*
         * Small page FLASH has a unique OOB layout, but large and huge
         * page FLASH use the standard layout. Small page FLASH uses a
         * custom BBT marker layout.
         */
        if (mtd->writesize <= 512)
                mtd_set_ooblayout(mtd, &lpc32xx_ooblayout_ops);

        chip->ecc.placement = NAND_ECC_PLACEMENT_INTERLEAVED;
        /* These sizes remain the same regardless of page size */
        chip->ecc.size = 256;
        chip->ecc.strength = 1;
        chip->ecc.bytes = LPC32XX_SLC_DEV_ECC_BYTES;
        chip->ecc.prepad = 0;
        chip->ecc.postpad = 0;
        chip->ecc.read_page_raw = lpc32xx_nand_read_page_raw_syndrome;
        chip->ecc.read_page = lpc32xx_nand_read_page_syndrome;
        chip->ecc.write_page_raw = lpc32xx_nand_write_page_raw_syndrome;
        chip->ecc.write_page = lpc32xx_nand_write_page_syndrome;
        chip->ecc.write_oob = lpc32xx_nand_write_oob_syndrome;
        chip->ecc.read_oob = lpc32xx_nand_read_oob_syndrome;
        chip->ecc.calculate = lpc32xx_nand_ecc_calculate;
        chip->ecc.correct = rawnand_sw_hamming_correct;
        chip->ecc.hwctl = lpc32xx_nand_ecc_enable;

        /*
         * Use a custom BBT marker setup for small page FLASH that
         * won't interfere with the ECC layout. Large and huge page
         * FLASH use the standard layout.
         */
        if ((chip->bbt_options & NAND_BBT_USE_FLASH) &&
            mtd->writesize <= 512) {
                chip->bbt_td = &bbt_smallpage_main_descr;
                chip->bbt_md = &bbt_smallpage_mirror_descr;
        }

        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 *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->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_dma = rc->start;
        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 = devm_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);

        chip = &host->nand_chip;
        mtd = nand_to_mtd(chip);
        nand_set_controller_data(chip, host);
        nand_set_flash_node(chip, pdev->dev.of_node);
        mtd->owner = THIS_MODULE;
        mtd->dev.parent = &pdev->dev;

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

        /* Set NAND IO addresses and command/ready functions */
        chip->legacy.IO_ADDR_R = SLC_DATA(host->io_base);
        chip->legacy.IO_ADDR_W = SLC_DATA(host->io_base);
        chip->legacy.cmd_ctrl = lpc32xx_nand_cmd_ctrl;
        chip->legacy.dev_ready = lpc32xx_nand_device_ready;
        chip->legacy.chip_delay = 20; /* 20us command delay time */

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

        platform_set_drvdata(pdev, host);

        /* NAND callbacks for LPC32xx SLC hardware */
        chip->legacy.read_byte = lpc32xx_nand_read_byte;
        chip->legacy.read_buf = lpc32xx_nand_read_buf;
        chip->legacy.write_buf = lpc32xx_nand_write_buf;

        /*
         * Allocate a large enough buffer for a single huge page plus
         * extra space for the spare area and ECC storage area
         */
        host->dma_buf_len = LPC32XX_DMA_DATA_SIZE + LPC32XX_ECC_SAVE_SIZE;
        host->data_buf = devm_kzalloc(&pdev->dev, host->dma_buf_len,
                                      GFP_KERNEL);
        if (host->data_buf == NULL) {
                res = -ENOMEM;
                goto enable_wp;
        }

        res = lpc32xx_nand_dma_setup(host);
        if (res) {
                res = -EIO;
                goto enable_wp;
        }

        /* Find NAND device */
        chip->legacy.dummy_controller.ops = &lpc32xx_nand_controller_ops;
        res = nand_scan(chip, 1);
        if (res)
                goto release_dma;

        mtd->name = "nxp_lpc3220_slc";
        res = mtd_device_register(mtd, host->ncfg->parts,
                                  host->ncfg->num_parts);
        if (res)
                goto cleanup_nand;

        return 0;

cleanup_nand:
        nand_cleanup(chip);
release_dma:
        dma_release_channel(host->dma_chan);
enable_wp:
        lpc32xx_wp_enable(host);

        return res;
}

/*
 * Remove NAND device.
 */
static void lpc32xx_nand_remove(struct platform_device *pdev)
{
        uint32_t tmp;
        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);
        dma_release_channel(host->dma_chan);

        /* Force CE high */
        tmp = readl(SLC_CTRL(host->io_base));
        tmp &= ~SLCCFG_CE_LOW;
        writel(tmp, SLC_CTRL(host->io_base));

        lpc32xx_wp_enable(host);
}

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)
{
        uint32_t tmp;
        struct lpc32xx_nand_host *host = platform_get_drvdata(pdev);

        /* Force CE high */
        tmp = readl(SLC_CTRL(host->io_base));
        tmp &= ~SLCCFG_CE_LOW;
        writel(tmp, SLC_CTRL(host->io_base));

        /* 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-slc" },
        { /* 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   = LPC32XX_MODNAME,
                .of_match_table = lpc32xx_nand_match,
        },
};

module_platform_driver(lpc32xx_nand_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Kevin Wells <kevin.wells@nxp.com>");
MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
MODULE_DESCRIPTION("NAND driver for the NXP LPC32XX SLC controller");