root/drivers/mtd/nand/raw/renesas-nand-controller.c
// SPDX-License-Identifier: GPL-2.0
/*
 * Evatronix/Renesas R-Car Gen3, RZ/N1D, RZ/N1S, RZ/N1L NAND controller driver
 *
 * Copyright (C) 2021 Schneider Electric
 * Author: Miquel RAYNAL <miquel.raynal@bootlin.com>
 */

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

#define COMMAND_REG 0x00
#define   COMMAND_SEQ(x) FIELD_PREP(GENMASK(5, 0), (x))
#define     COMMAND_SEQ_10 COMMAND_SEQ(0x2A)
#define     COMMAND_SEQ_12 COMMAND_SEQ(0x0C)
#define     COMMAND_SEQ_18 COMMAND_SEQ(0x32)
#define     COMMAND_SEQ_19 COMMAND_SEQ(0x13)
#define     COMMAND_SEQ_GEN_IN COMMAND_SEQ_18
#define     COMMAND_SEQ_GEN_OUT COMMAND_SEQ_19
#define     COMMAND_SEQ_READ_PAGE COMMAND_SEQ_10
#define     COMMAND_SEQ_WRITE_PAGE COMMAND_SEQ_12
#define   COMMAND_INPUT_SEL_AHBS 0
#define   COMMAND_INPUT_SEL_DMA BIT(6)
#define   COMMAND_FIFO_SEL 0
#define   COMMAND_DATA_SEL BIT(7)
#define   COMMAND_0(x) FIELD_PREP(GENMASK(15, 8), (x))
#define   COMMAND_1(x) FIELD_PREP(GENMASK(23, 16), (x))
#define   COMMAND_2(x) FIELD_PREP(GENMASK(31, 24), (x))

#define CONTROL_REG 0x04
#define   CONTROL_CHECK_RB_LINE 0
#define   CONTROL_ECC_BLOCK_SIZE(x) FIELD_PREP(GENMASK(2, 1), (x))
#define     CONTROL_ECC_BLOCK_SIZE_256 CONTROL_ECC_BLOCK_SIZE(0)
#define     CONTROL_ECC_BLOCK_SIZE_512 CONTROL_ECC_BLOCK_SIZE(1)
#define     CONTROL_ECC_BLOCK_SIZE_1024 CONTROL_ECC_BLOCK_SIZE(2)
#define   CONTROL_INT_EN BIT(4)
#define   CONTROL_ECC_EN BIT(5)
#define   CONTROL_BLOCK_SIZE(x) FIELD_PREP(GENMASK(7, 6), (x))
#define     CONTROL_BLOCK_SIZE_32P CONTROL_BLOCK_SIZE(0)
#define     CONTROL_BLOCK_SIZE_64P CONTROL_BLOCK_SIZE(1)
#define     CONTROL_BLOCK_SIZE_128P CONTROL_BLOCK_SIZE(2)
#define     CONTROL_BLOCK_SIZE_256P CONTROL_BLOCK_SIZE(3)

#define STATUS_REG 0x8
#define   MEM_RDY(cs, reg) (FIELD_GET(GENMASK(3, 0), (reg)) & BIT(cs))
#define   CTRL_RDY(reg) (FIELD_GET(BIT(8), (reg)) == 0)

#define ECC_CTRL_REG 0x18
#define   ECC_CTRL_CAP(x) FIELD_PREP(GENMASK(2, 0), (x))
#define     ECC_CTRL_CAP_2B ECC_CTRL_CAP(0)
#define     ECC_CTRL_CAP_4B ECC_CTRL_CAP(1)
#define     ECC_CTRL_CAP_8B ECC_CTRL_CAP(2)
#define     ECC_CTRL_CAP_16B ECC_CTRL_CAP(3)
#define     ECC_CTRL_CAP_24B ECC_CTRL_CAP(4)
#define     ECC_CTRL_CAP_32B ECC_CTRL_CAP(5)
#define   ECC_CTRL_ERR_THRESHOLD(x) FIELD_PREP(GENMASK(13, 8), (x))

#define INT_MASK_REG 0x10
#define INT_STATUS_REG 0x14
#define   INT_CMD_END BIT(1)
#define   INT_DMA_END BIT(3)
#define   INT_MEM_RDY(cs) FIELD_PREP(GENMASK(11, 8), BIT(cs))
#define   INT_DMA_ENDED BIT(3)
#define   MEM_IS_RDY(cs, reg) (FIELD_GET(GENMASK(11, 8), (reg)) & BIT(cs))
#define   DMA_HAS_ENDED(reg) FIELD_GET(BIT(3), (reg))

#define ECC_OFFSET_REG 0x1C
#define   ECC_OFFSET(x) FIELD_PREP(GENMASK(15, 0), (x))

#define ECC_STAT_REG 0x20
#define   ECC_STAT_CORRECTABLE(cs, reg) (FIELD_GET(GENMASK(3, 0), (reg)) & BIT(cs))
#define   ECC_STAT_UNCORRECTABLE(cs, reg) (FIELD_GET(GENMASK(11, 8), (reg)) & BIT(cs))

#define ADDR0_COL_REG 0x24
#define   ADDR0_COL(x) FIELD_PREP(GENMASK(15, 0), (x))

#define ADDR0_ROW_REG 0x28
#define   ADDR0_ROW(x) FIELD_PREP(GENMASK(23, 0), (x))

#define ADDR1_COL_REG 0x2C
#define   ADDR1_COL(x) FIELD_PREP(GENMASK(15, 0), (x))

#define ADDR1_ROW_REG 0x30
#define   ADDR1_ROW(x) FIELD_PREP(GENMASK(23, 0), (x))

#define FIFO_DATA_REG 0x38

#define DATA_REG 0x3C

#define DATA_REG_SIZE_REG 0x40

#define DMA_ADDR_LOW_REG 0x64

#define DMA_ADDR_HIGH_REG 0x68

#define DMA_CNT_REG 0x6C

#define DMA_CTRL_REG 0x70
#define   DMA_CTRL_INCREMENT_BURST_4 0
#define   DMA_CTRL_REGISTER_MANAGED_MODE 0
#define   DMA_CTRL_START BIT(7)

#define MEM_CTRL_REG 0x80
#define   MEM_CTRL_CS(cs) FIELD_PREP(GENMASK(1, 0), (cs))
#define   MEM_CTRL_DIS_WP(cs) FIELD_PREP(GENMASK(11, 8), BIT((cs)))

#define DATA_SIZE_REG 0x84
#define   DATA_SIZE(x) FIELD_PREP(GENMASK(14, 0), (x))

#define TIMINGS_ASYN_REG 0x88
#define   TIMINGS_ASYN_TRWP(x) FIELD_PREP(GENMASK(3, 0), max((x), 1U) - 1)
#define   TIMINGS_ASYN_TRWH(x) FIELD_PREP(GENMASK(7, 4), max((x), 1U) - 1)

#define TIM_SEQ0_REG 0x90
#define   TIM_SEQ0_TCCS(x) FIELD_PREP(GENMASK(5, 0), max((x), 1U) - 1)
#define   TIM_SEQ0_TADL(x) FIELD_PREP(GENMASK(13, 8), max((x), 1U) - 1)
#define   TIM_SEQ0_TRHW(x) FIELD_PREP(GENMASK(21, 16), max((x), 1U) - 1)
#define   TIM_SEQ0_TWHR(x) FIELD_PREP(GENMASK(29, 24), max((x), 1U) - 1)

#define TIM_SEQ1_REG 0x94
#define   TIM_SEQ1_TWB(x) FIELD_PREP(GENMASK(5, 0), max((x), 1U) - 1)
#define   TIM_SEQ1_TRR(x) FIELD_PREP(GENMASK(13, 8), max((x), 1U) - 1)
#define   TIM_SEQ1_TWW(x) FIELD_PREP(GENMASK(21, 16), max((x), 1U) - 1)

#define TIM_GEN_SEQ0_REG 0x98
#define   TIM_GEN_SEQ0_D0(x) FIELD_PREP(GENMASK(5, 0), max((x), 1U) - 1)
#define   TIM_GEN_SEQ0_D1(x) FIELD_PREP(GENMASK(13, 8), max((x), 1U) - 1)
#define   TIM_GEN_SEQ0_D2(x) FIELD_PREP(GENMASK(21, 16), max((x), 1U) - 1)
#define   TIM_GEN_SEQ0_D3(x) FIELD_PREP(GENMASK(29, 24), max((x), 1U) - 1)

#define TIM_GEN_SEQ1_REG 0x9c
#define   TIM_GEN_SEQ1_D4(x) FIELD_PREP(GENMASK(5, 0), max((x), 1U) - 1)
#define   TIM_GEN_SEQ1_D5(x) FIELD_PREP(GENMASK(13, 8), max((x), 1U) - 1)
#define   TIM_GEN_SEQ1_D6(x) FIELD_PREP(GENMASK(21, 16), max((x), 1U) - 1)
#define   TIM_GEN_SEQ1_D7(x) FIELD_PREP(GENMASK(29, 24), max((x), 1U) - 1)

#define TIM_GEN_SEQ2_REG 0xA0
#define   TIM_GEN_SEQ2_D8(x) FIELD_PREP(GENMASK(5, 0), max((x), 1U) - 1)
#define   TIM_GEN_SEQ2_D9(x) FIELD_PREP(GENMASK(13, 8), max((x), 1U) - 1)
#define   TIM_GEN_SEQ2_D10(x) FIELD_PREP(GENMASK(21, 16), max((x), 1U) - 1)
#define   TIM_GEN_SEQ2_D11(x) FIELD_PREP(GENMASK(29, 24), max((x), 1U) - 1)

#define FIFO_INIT_REG 0xB4
#define   FIFO_INIT BIT(0)

#define FIFO_STATE_REG 0xB4
#define   FIFO_STATE_R_EMPTY(reg) FIELD_GET(BIT(0), (reg))
#define   FIFO_STATE_W_FULL(reg) FIELD_GET(BIT(1), (reg))
#define   FIFO_STATE_C_EMPTY(reg) FIELD_GET(BIT(2), (reg))
#define   FIFO_STATE_R_FULL(reg) FIELD_GET(BIT(6), (reg))
#define   FIFO_STATE_W_EMPTY(reg) FIELD_GET(BIT(7), (reg))

#define GEN_SEQ_CTRL_REG 0xB8
#define   GEN_SEQ_CMD0_EN BIT(0)
#define   GEN_SEQ_CMD1_EN BIT(1)
#define   GEN_SEQ_CMD2_EN BIT(2)
#define   GEN_SEQ_CMD3_EN BIT(3)
#define   GEN_SEQ_COL_A0(x) FIELD_PREP(GENMASK(5, 4), min((x), 2U))
#define   GEN_SEQ_COL_A1(x) FIELD_PREP(GENMASK(7, 6), min((x), 2U))
#define   GEN_SEQ_ROW_A0(x) FIELD_PREP(GENMASK(9, 8), min((x), 3U))
#define   GEN_SEQ_ROW_A1(x) FIELD_PREP(GENMASK(11, 10), min((x), 3U))
#define   GEN_SEQ_DATA_EN BIT(12)
#define   GEN_SEQ_DELAY_EN(x) FIELD_PREP(GENMASK(14, 13), (x))
#define     GEN_SEQ_DELAY0_EN GEN_SEQ_DELAY_EN(1)
#define     GEN_SEQ_DELAY1_EN GEN_SEQ_DELAY_EN(2)
#define   GEN_SEQ_IMD_SEQ BIT(15)
#define   GEN_SEQ_COMMAND_3(x) FIELD_PREP(GENMASK(26, 16), (x))

#define DMA_TLVL_REG 0x114
#define   DMA_TLVL(x) FIELD_PREP(GENMASK(7, 0), (x))
#define   DMA_TLVL_MAX DMA_TLVL(0xFF)

#define TIM_GEN_SEQ3_REG 0x134
#define   TIM_GEN_SEQ3_D12(x) FIELD_PREP(GENMASK(5, 0), max((x), 1U) - 1)

#define ECC_CNT_REG 0x14C
#define   ECC_CNT(cs, reg) FIELD_GET(GENMASK(5, 0), (reg) >> ((cs) * 8))

#define RNANDC_CS_NUM 4

#define TO_CYCLES64(ps, period_ns) ((unsigned int)DIV_ROUND_UP_ULL(div_u64(ps, 1000), \
                                                                   period_ns))

struct rnand_chip_sel {
        unsigned int cs;
};

struct rnand_chip {
        struct nand_chip chip;
        struct list_head node;
        int selected_die;
        u32 ctrl;
        unsigned int nsels;
        u32 control;
        u32 ecc_ctrl;
        u32 timings_asyn;
        u32 tim_seq0;
        u32 tim_seq1;
        u32 tim_gen_seq0;
        u32 tim_gen_seq1;
        u32 tim_gen_seq2;
        u32 tim_gen_seq3;
        struct rnand_chip_sel sels[] __counted_by(nsels);
};

struct rnandc {
        struct nand_controller controller;
        struct device *dev;
        void __iomem *regs;
        unsigned long ext_clk_rate;
        unsigned long assigned_cs;
        struct list_head chips;
        struct nand_chip *selected_chip;
        struct completion complete;
        bool use_polling;
        u8 *buf;
        unsigned int buf_sz;
};

struct rnandc_op {
        u32 command;
        u32 addr0_col;
        u32 addr0_row;
        u32 addr1_col;
        u32 addr1_row;
        u32 data_size;
        u32 ecc_offset;
        u32 gen_seq_ctrl;
        u8 *buf;
        bool read;
        unsigned int len;
};

static inline struct rnandc *to_rnandc(struct nand_controller *ctrl)
{
        return container_of(ctrl, struct rnandc, controller);
}

static inline struct rnand_chip *to_rnand(struct nand_chip *chip)
{
        return container_of(chip, struct rnand_chip, chip);
}

static inline unsigned int to_rnandc_cs(struct rnand_chip *nand)
{
        return nand->sels[nand->selected_die].cs;
}

static void rnandc_dis_correction(struct rnandc *rnandc)
{
        u32 control;

        control = readl_relaxed(rnandc->regs + CONTROL_REG);
        control &= ~CONTROL_ECC_EN;
        writel_relaxed(control, rnandc->regs + CONTROL_REG);
}

static void rnandc_en_correction(struct rnandc *rnandc)
{
        u32 control;

        control = readl_relaxed(rnandc->regs + CONTROL_REG);
        control |= CONTROL_ECC_EN;
        writel_relaxed(control, rnandc->regs + CONTROL_REG);
}

static void rnandc_clear_status(struct rnandc *rnandc)
{
        writel_relaxed(0, rnandc->regs + INT_STATUS_REG);
        writel_relaxed(0, rnandc->regs + ECC_STAT_REG);
        writel_relaxed(0, rnandc->regs + ECC_CNT_REG);
}

static void rnandc_dis_interrupts(struct rnandc *rnandc)
{
        writel_relaxed(0, rnandc->regs + INT_MASK_REG);
}

static void rnandc_en_interrupts(struct rnandc *rnandc, u32 val)
{
        if (!rnandc->use_polling)
                writel_relaxed(val, rnandc->regs + INT_MASK_REG);
}

static void rnandc_clear_fifo(struct rnandc *rnandc)
{
        writel_relaxed(FIFO_INIT, rnandc->regs + FIFO_INIT_REG);
}

static void rnandc_select_target(struct nand_chip *chip, int die_nr)
{
        struct rnand_chip *rnand = to_rnand(chip);
        struct rnandc *rnandc = to_rnandc(chip->controller);
        unsigned int cs = rnand->sels[die_nr].cs;

        if (chip == rnandc->selected_chip && die_nr == rnand->selected_die)
                return;

        rnandc_clear_status(rnandc);
        writel_relaxed(MEM_CTRL_CS(cs) | MEM_CTRL_DIS_WP(cs), rnandc->regs + MEM_CTRL_REG);
        writel_relaxed(rnand->control, rnandc->regs + CONTROL_REG);
        writel_relaxed(rnand->ecc_ctrl, rnandc->regs + ECC_CTRL_REG);
        writel_relaxed(rnand->timings_asyn, rnandc->regs + TIMINGS_ASYN_REG);
        writel_relaxed(rnand->tim_seq0, rnandc->regs + TIM_SEQ0_REG);
        writel_relaxed(rnand->tim_seq1, rnandc->regs + TIM_SEQ1_REG);
        writel_relaxed(rnand->tim_gen_seq0, rnandc->regs + TIM_GEN_SEQ0_REG);
        writel_relaxed(rnand->tim_gen_seq1, rnandc->regs + TIM_GEN_SEQ1_REG);
        writel_relaxed(rnand->tim_gen_seq2, rnandc->regs + TIM_GEN_SEQ2_REG);
        writel_relaxed(rnand->tim_gen_seq3, rnandc->regs + TIM_GEN_SEQ3_REG);

        rnandc->selected_chip = chip;
        rnand->selected_die = die_nr;
}

static void rnandc_trigger_op(struct rnandc *rnandc, struct rnandc_op *rop)
{
        writel_relaxed(rop->addr0_col, rnandc->regs + ADDR0_COL_REG);
        writel_relaxed(rop->addr0_row, rnandc->regs + ADDR0_ROW_REG);
        writel_relaxed(rop->addr1_col, rnandc->regs + ADDR1_COL_REG);
        writel_relaxed(rop->addr1_row, rnandc->regs + ADDR1_ROW_REG);
        writel_relaxed(rop->ecc_offset, rnandc->regs + ECC_OFFSET_REG);
        writel_relaxed(rop->gen_seq_ctrl, rnandc->regs + GEN_SEQ_CTRL_REG);
        writel_relaxed(DATA_SIZE(rop->len), rnandc->regs + DATA_SIZE_REG);
        writel_relaxed(rop->command, rnandc->regs + COMMAND_REG);
}

static void rnandc_trigger_dma(struct rnandc *rnandc)
{
        writel_relaxed(DMA_CTRL_INCREMENT_BURST_4 |
                       DMA_CTRL_REGISTER_MANAGED_MODE |
                       DMA_CTRL_START, rnandc->regs + DMA_CTRL_REG);
}

static irqreturn_t rnandc_irq_handler(int irq, void *private)
{
        struct rnandc *rnandc = private;

        rnandc_dis_interrupts(rnandc);
        complete(&rnandc->complete);

        return IRQ_HANDLED;
}

static int rnandc_wait_end_of_op(struct rnandc *rnandc,
                                 struct nand_chip *chip)
{
        struct rnand_chip *rnand = to_rnand(chip);
        unsigned int cs = to_rnandc_cs(rnand);
        u32 status;
        int ret;

        ret = readl_poll_timeout(rnandc->regs + STATUS_REG, status,
                                 MEM_RDY(cs, status) && CTRL_RDY(status),
                                 1, 100000);
        if (ret)
                dev_err(rnandc->dev, "Operation timed out, status: 0x%08x\n",
                        status);

        return ret;
}

static int rnandc_wait_end_of_io(struct rnandc *rnandc,
                                 struct nand_chip *chip)
{
        int timeout_ms = 1000;
        int ret;

        if (rnandc->use_polling) {
                struct rnand_chip *rnand = to_rnand(chip);
                unsigned int cs = to_rnandc_cs(rnand);
                u32 status;

                ret = readl_poll_timeout(rnandc->regs + INT_STATUS_REG, status,
                                         MEM_IS_RDY(cs, status) &
                                         DMA_HAS_ENDED(status),
                                         0, timeout_ms * 1000);
        } else {
                ret = wait_for_completion_timeout(&rnandc->complete,
                                                  msecs_to_jiffies(timeout_ms));
                if (!ret)
                        ret = -ETIMEDOUT;
                else
                        ret = 0;
        }

        return ret;
}

static int rnandc_read_page_hw_ecc(struct nand_chip *chip, u8 *buf,
                                   int oob_required, int page)
{
        struct rnandc *rnandc = to_rnandc(chip->controller);
        struct mtd_info *mtd = nand_to_mtd(chip);
        struct rnand_chip *rnand = to_rnand(chip);
        unsigned int cs = to_rnandc_cs(rnand);
        struct rnandc_op rop = {
                .command = COMMAND_INPUT_SEL_DMA | COMMAND_0(NAND_CMD_READ0) |
                           COMMAND_2(NAND_CMD_READSTART) | COMMAND_FIFO_SEL |
                           COMMAND_SEQ_READ_PAGE,
                .addr0_row = page,
                .len = mtd->writesize,
                .ecc_offset = ECC_OFFSET(mtd->writesize + 2),
        };
        unsigned int max_bitflips = 0;
        dma_addr_t dma_addr;
        u32 ecc_stat;
        int bf, ret, i;

        /* Prepare controller */
        rnandc_select_target(chip, chip->cur_cs);
        rnandc_clear_status(rnandc);
        reinit_completion(&rnandc->complete);
        rnandc_en_interrupts(rnandc, INT_DMA_ENDED);
        rnandc_en_correction(rnandc);

        /* Configure DMA */
        dma_addr = dma_map_single(rnandc->dev, rnandc->buf, mtd->writesize,
                                  DMA_FROM_DEVICE);
        if (dma_mapping_error(rnandc->dev, dma_addr))
                return -ENOMEM;

        writel(dma_addr, rnandc->regs + DMA_ADDR_LOW_REG);
        writel(mtd->writesize, rnandc->regs + DMA_CNT_REG);
        writel(DMA_TLVL_MAX, rnandc->regs + DMA_TLVL_REG);

        rnandc_trigger_op(rnandc, &rop);
        rnandc_trigger_dma(rnandc);

        ret = rnandc_wait_end_of_io(rnandc, chip);
        dma_unmap_single(rnandc->dev, dma_addr, mtd->writesize, DMA_FROM_DEVICE);
        rnandc_dis_correction(rnandc);
        if (ret) {
                dev_err(rnandc->dev, "Read page operation never ending\n");
                return ret;
        }

        ecc_stat = readl_relaxed(rnandc->regs + ECC_STAT_REG);

        if (oob_required || ECC_STAT_UNCORRECTABLE(cs, ecc_stat)) {
                ret = nand_change_read_column_op(chip, mtd->writesize,
                                                 chip->oob_poi, mtd->oobsize,
                                                 false);
                if (ret)
                        return ret;
        }

        if (ECC_STAT_UNCORRECTABLE(cs, ecc_stat)) {
                for (i = 0; i < chip->ecc.steps; i++) {
                        unsigned int off = i * chip->ecc.size;
                        unsigned int eccoff = i * chip->ecc.bytes;

                        bf = nand_check_erased_ecc_chunk(rnandc->buf + off,
                                                         chip->ecc.size,
                                                         chip->oob_poi + 2 + eccoff,
                                                         chip->ecc.bytes,
                                                         NULL, 0,
                                                         chip->ecc.strength);
                        if (bf < 0) {
                                mtd->ecc_stats.failed++;
                        } else {
                                mtd->ecc_stats.corrected += bf;
                                max_bitflips = max_t(unsigned int, max_bitflips, bf);
                        }
                }
        } else if (ECC_STAT_CORRECTABLE(cs, ecc_stat)) {
                bf = ECC_CNT(cs, readl_relaxed(rnandc->regs + ECC_CNT_REG));
                /*
                 * The number of bitflips is an approximation given the fact
                 * that this controller does not provide per-chunk details but
                 * only gives statistics on the entire page.
                 */
                mtd->ecc_stats.corrected += bf;
        }

        memcpy(buf, rnandc->buf, mtd->writesize);

        return 0;
}

static int rnandc_read_subpage_hw_ecc(struct nand_chip *chip, u32 req_offset,
                                      u32 req_len, u8 *bufpoi, int page)
{
        struct rnandc *rnandc = to_rnandc(chip->controller);
        struct mtd_info *mtd = nand_to_mtd(chip);
        struct rnand_chip *rnand = to_rnand(chip);
        unsigned int cs = to_rnandc_cs(rnand);
        unsigned int page_off = round_down(req_offset, chip->ecc.size);
        unsigned int real_len = round_up(req_offset + req_len - page_off,
                                         chip->ecc.size);
        unsigned int start_chunk = page_off / chip->ecc.size;
        unsigned int nchunks = real_len / chip->ecc.size;
        unsigned int ecc_off = 2 + (start_chunk * chip->ecc.bytes);
        struct rnandc_op rop = {
                .command = COMMAND_INPUT_SEL_AHBS | COMMAND_0(NAND_CMD_READ0) |
                           COMMAND_2(NAND_CMD_READSTART) | COMMAND_FIFO_SEL |
                           COMMAND_SEQ_READ_PAGE,
                .addr0_row = page,
                .addr0_col = page_off,
                .len = real_len,
                .ecc_offset = ECC_OFFSET(mtd->writesize + ecc_off),
        };
        unsigned int max_bitflips = 0, i;
        u32 ecc_stat;
        int bf, ret;

        /* Prepare controller */
        rnandc_select_target(chip, chip->cur_cs);
        rnandc_clear_status(rnandc);
        rnandc_en_correction(rnandc);
        rnandc_trigger_op(rnandc, &rop);

        while (!FIFO_STATE_C_EMPTY(readl(rnandc->regs + FIFO_STATE_REG)))
                cpu_relax();

        while (FIFO_STATE_R_EMPTY(readl(rnandc->regs + FIFO_STATE_REG)))
                cpu_relax();

        ioread32_rep(rnandc->regs + FIFO_DATA_REG, bufpoi + page_off,
                     real_len / 4);

        if (!FIFO_STATE_R_EMPTY(readl(rnandc->regs + FIFO_STATE_REG))) {
                dev_err(rnandc->dev, "Clearing residual data in the read FIFO\n");
                rnandc_clear_fifo(rnandc);
        }

        ret = rnandc_wait_end_of_op(rnandc, chip);
        rnandc_dis_correction(rnandc);
        if (ret) {
                dev_err(rnandc->dev, "Read subpage operation never ending\n");
                return ret;
        }

        ecc_stat = readl_relaxed(rnandc->regs + ECC_STAT_REG);

        if (ECC_STAT_UNCORRECTABLE(cs, ecc_stat)) {
                ret = nand_change_read_column_op(chip, mtd->writesize,
                                                 chip->oob_poi, mtd->oobsize,
                                                 false);
                if (ret)
                        return ret;

                for (i = start_chunk; i < nchunks; i++) {
                        unsigned int dataoff = i * chip->ecc.size;
                        unsigned int eccoff = 2 + (i * chip->ecc.bytes);

                        bf = nand_check_erased_ecc_chunk(bufpoi + dataoff,
                                                         chip->ecc.size,
                                                         chip->oob_poi + eccoff,
                                                         chip->ecc.bytes,
                                                         NULL, 0,
                                                         chip->ecc.strength);
                        if (bf < 0) {
                                mtd->ecc_stats.failed++;
                        } else {
                                mtd->ecc_stats.corrected += bf;
                                max_bitflips = max_t(unsigned int, max_bitflips, bf);
                        }
                }
        } else if (ECC_STAT_CORRECTABLE(cs, ecc_stat)) {
                bf = ECC_CNT(cs, readl_relaxed(rnandc->regs + ECC_CNT_REG));
                /*
                 * The number of bitflips is an approximation given the fact
                 * that this controller does not provide per-chunk details but
                 * only gives statistics on the entire page.
                 */
                mtd->ecc_stats.corrected += bf;
        }

        return 0;
}

static int rnandc_write_page_hw_ecc(struct nand_chip *chip, const u8 *buf,
                                    int oob_required, int page)
{
        struct rnandc *rnandc = to_rnandc(chip->controller);
        struct mtd_info *mtd = nand_to_mtd(chip);
        struct rnand_chip *rnand = to_rnand(chip);
        unsigned int cs = to_rnandc_cs(rnand);
        struct rnandc_op rop = {
                .command = COMMAND_INPUT_SEL_DMA | COMMAND_0(NAND_CMD_SEQIN) |
                           COMMAND_1(NAND_CMD_PAGEPROG) | COMMAND_FIFO_SEL |
                           COMMAND_SEQ_WRITE_PAGE,
                .addr0_row = page,
                .len = mtd->writesize,
                .ecc_offset = ECC_OFFSET(mtd->writesize + 2),
        };
        dma_addr_t dma_addr;
        int ret;

        memcpy(rnandc->buf, buf, mtd->writesize);

        /* Prepare controller */
        rnandc_select_target(chip, chip->cur_cs);
        rnandc_clear_status(rnandc);
        reinit_completion(&rnandc->complete);
        rnandc_en_interrupts(rnandc, INT_MEM_RDY(cs));
        rnandc_en_correction(rnandc);

        /* Configure DMA */
        dma_addr = dma_map_single(rnandc->dev, (void *)rnandc->buf, mtd->writesize,
                                  DMA_TO_DEVICE);
        if (dma_mapping_error(rnandc->dev, dma_addr))
                return -ENOMEM;

        writel(dma_addr, rnandc->regs + DMA_ADDR_LOW_REG);
        writel(mtd->writesize, rnandc->regs + DMA_CNT_REG);
        writel(DMA_TLVL_MAX, rnandc->regs + DMA_TLVL_REG);

        rnandc_trigger_op(rnandc, &rop);
        rnandc_trigger_dma(rnandc);

        ret = rnandc_wait_end_of_io(rnandc, chip);
        dma_unmap_single(rnandc->dev, dma_addr, mtd->writesize, DMA_TO_DEVICE);
        rnandc_dis_correction(rnandc);
        if (ret) {
                dev_err(rnandc->dev, "Write page operation never ending\n");
                return ret;
        }

        if (!oob_required)
                return 0;

        return nand_change_write_column_op(chip, mtd->writesize, chip->oob_poi,
                                           mtd->oobsize, false);
}

static int rnandc_write_subpage_hw_ecc(struct nand_chip *chip, u32 req_offset,
                                       u32 req_len, const u8 *bufpoi,
                                       int oob_required, int page)
{
        struct rnandc *rnandc = to_rnandc(chip->controller);
        struct mtd_info *mtd = nand_to_mtd(chip);
        unsigned int page_off = round_down(req_offset, chip->ecc.size);
        unsigned int real_len = round_up(req_offset + req_len - page_off,
                                         chip->ecc.size);
        unsigned int start_chunk = page_off / chip->ecc.size;
        unsigned int ecc_off = 2 + (start_chunk * chip->ecc.bytes);
        struct rnandc_op rop = {
                .command = COMMAND_INPUT_SEL_AHBS | COMMAND_0(NAND_CMD_SEQIN) |
                           COMMAND_1(NAND_CMD_PAGEPROG) | COMMAND_FIFO_SEL |
                           COMMAND_SEQ_WRITE_PAGE,
                .addr0_row = page,
                .addr0_col = page_off,
                .len = real_len,
                .ecc_offset = ECC_OFFSET(mtd->writesize + ecc_off),
        };
        int ret;

        /* Prepare controller */
        rnandc_select_target(chip, chip->cur_cs);
        rnandc_clear_status(rnandc);
        rnandc_en_correction(rnandc);
        rnandc_trigger_op(rnandc, &rop);

        while (FIFO_STATE_W_FULL(readl(rnandc->regs + FIFO_STATE_REG)))
                cpu_relax();

        iowrite32_rep(rnandc->regs + FIFO_DATA_REG, bufpoi + page_off,
                      real_len / 4);

        while (!FIFO_STATE_W_EMPTY(readl(rnandc->regs + FIFO_STATE_REG)))
                cpu_relax();

        ret = rnandc_wait_end_of_op(rnandc, chip);
        rnandc_dis_correction(rnandc);
        if (ret) {
                dev_err(rnandc->dev, "Write subpage operation never ending\n");
                return ret;
        }

        return 0;
}

/*
 * This controller is simple enough and thus does not need to use the parser
 * provided by the core, instead, handle every situation here.
 */
static int rnandc_exec_op(struct nand_chip *chip,
                          const struct nand_operation *op, bool check_only)
{
        struct rnandc *rnandc = to_rnandc(chip->controller);
        const struct nand_op_instr *instr = NULL;
        struct rnandc_op rop = {
                .command = COMMAND_INPUT_SEL_AHBS,
                .gen_seq_ctrl = GEN_SEQ_IMD_SEQ,
        };
        unsigned int cmd_phase = 0, addr_phase = 0, data_phase = 0,
                delay_phase = 0, delays = 0;
        unsigned int op_id, col_addrs, row_addrs, naddrs, remainder, words, i;
        const u8 *addrs;
        u32 last_bytes;
        int ret;

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

        for (op_id = 0; op_id < op->ninstrs; op_id++) {
                instr = &op->instrs[op_id];

                nand_op_trace("  ", instr);

                switch (instr->type) {
                case NAND_OP_CMD_INSTR:
                        switch (cmd_phase++) {
                        case 0:
                                rop.command |= COMMAND_0(instr->ctx.cmd.opcode);
                                rop.gen_seq_ctrl |= GEN_SEQ_CMD0_EN;
                                break;
                        case 1:
                                rop.gen_seq_ctrl |= GEN_SEQ_COMMAND_3(instr->ctx.cmd.opcode);
                                rop.gen_seq_ctrl |= GEN_SEQ_CMD3_EN;
                                if (addr_phase == 0)
                                        addr_phase = 1;
                                break;
                        case 2:
                                rop.command |= COMMAND_2(instr->ctx.cmd.opcode);
                                rop.gen_seq_ctrl |= GEN_SEQ_CMD2_EN;
                                if (addr_phase <= 1)
                                        addr_phase = 2;
                                break;
                        case 3:
                                rop.command |= COMMAND_1(instr->ctx.cmd.opcode);
                                rop.gen_seq_ctrl |= GEN_SEQ_CMD1_EN;
                                if (addr_phase <= 1)
                                        addr_phase = 2;
                                if (delay_phase == 0)
                                        delay_phase = 1;
                                if (data_phase == 0)
                                        data_phase = 1;
                                break;
                        default:
                                return -EOPNOTSUPP;
                        }
                        break;

                case NAND_OP_ADDR_INSTR:
                        addrs = instr->ctx.addr.addrs;
                        naddrs = instr->ctx.addr.naddrs;
                        if (naddrs > 5)
                                return -EOPNOTSUPP;

                        col_addrs = min(2U, naddrs);
                        row_addrs = naddrs > 2 ? naddrs - col_addrs : 0;

                        switch (addr_phase++) {
                        case 0:
                                for (i = 0; i < col_addrs; i++)
                                        rop.addr0_col |= addrs[i] << (i * 8);
                                rop.gen_seq_ctrl |= GEN_SEQ_COL_A0(col_addrs);

                                for (i = 0; i < row_addrs; i++)
                                        rop.addr0_row |= addrs[2 + i] << (i * 8);
                                rop.gen_seq_ctrl |= GEN_SEQ_ROW_A0(row_addrs);

                                if (cmd_phase == 0)
                                        cmd_phase = 1;
                                break;
                        case 1:
                                for (i = 0; i < col_addrs; i++)
                                        rop.addr1_col |= addrs[i] << (i * 8);
                                rop.gen_seq_ctrl |= GEN_SEQ_COL_A1(col_addrs);

                                for (i = 0; i < row_addrs; i++)
                                        rop.addr1_row |= addrs[2 + i] << (i * 8);
                                rop.gen_seq_ctrl |= GEN_SEQ_ROW_A1(row_addrs);

                                if (cmd_phase <= 1)
                                        cmd_phase = 2;
                                break;
                        default:
                                return -EOPNOTSUPP;
                        }
                        break;

                case NAND_OP_DATA_IN_INSTR:
                        rop.read = true;
                        fallthrough;
                case NAND_OP_DATA_OUT_INSTR:
                        rop.gen_seq_ctrl |= GEN_SEQ_DATA_EN;
                        rop.buf = instr->ctx.data.buf.in;
                        rop.len = instr->ctx.data.len;
                        rop.command |= COMMAND_FIFO_SEL;

                        switch (data_phase++) {
                        case 0:
                                if (cmd_phase <= 2)
                                        cmd_phase = 3;
                                if (addr_phase <= 1)
                                        addr_phase = 2;
                                if (delay_phase == 0)
                                        delay_phase = 1;
                                break;
                        default:
                                return -EOPNOTSUPP;
                        }
                        break;

                case NAND_OP_WAITRDY_INSTR:
                        switch (delay_phase++) {
                        case 0:
                                rop.gen_seq_ctrl |= GEN_SEQ_DELAY0_EN;

                                if (cmd_phase <= 2)
                                        cmd_phase = 3;
                                break;
                        case 1:
                                rop.gen_seq_ctrl |= GEN_SEQ_DELAY1_EN;

                                if (cmd_phase <= 3)
                                        cmd_phase = 4;
                                if (data_phase == 0)
                                        data_phase = 1;
                                break;
                        default:
                                return -EOPNOTSUPP;
                        }
                        break;
                }
        }

        /*
         * Sequence 19 is generic and dedicated to write operations.
         * Sequence 18 is also generic and works for all other operations.
         */
        if (rop.buf && !rop.read)
                rop.command |= COMMAND_SEQ_GEN_OUT;
        else
                rop.command |= COMMAND_SEQ_GEN_IN;

        if (delays > 1) {
                dev_err(rnandc->dev, "Cannot handle more than one wait delay\n");
                return -EOPNOTSUPP;
        }

        if (check_only)
                return 0;

        rnandc_trigger_op(rnandc, &rop);

        words = rop.len / sizeof(u32);
        remainder = rop.len % sizeof(u32);
        if (rop.buf && rop.read) {
                while (!FIFO_STATE_C_EMPTY(readl(rnandc->regs + FIFO_STATE_REG)))
                        cpu_relax();

                while (FIFO_STATE_R_EMPTY(readl(rnandc->regs + FIFO_STATE_REG)))
                        cpu_relax();

                ioread32_rep(rnandc->regs + FIFO_DATA_REG, rop.buf, words);
                if (remainder) {
                        last_bytes = readl_relaxed(rnandc->regs + FIFO_DATA_REG);
                        memcpy(rop.buf + (words * sizeof(u32)), &last_bytes,
                               remainder);
                }

                if (!FIFO_STATE_R_EMPTY(readl(rnandc->regs + FIFO_STATE_REG))) {
                        dev_warn(rnandc->dev,
                                 "Clearing residual data in the read FIFO\n");
                        rnandc_clear_fifo(rnandc);
                }
        } else if (rop.len && !rop.read) {
                while (FIFO_STATE_W_FULL(readl(rnandc->regs + FIFO_STATE_REG)))
                        cpu_relax();

                iowrite32_rep(rnandc->regs + FIFO_DATA_REG, rop.buf,
                              DIV_ROUND_UP(rop.len, 4));

                if (remainder) {
                        last_bytes = 0;
                        memcpy(&last_bytes, rop.buf + (words * sizeof(u32)), remainder);
                        writel_relaxed(last_bytes, rnandc->regs + FIFO_DATA_REG);
                }

                while (!FIFO_STATE_W_EMPTY(readl(rnandc->regs + FIFO_STATE_REG)))
                        cpu_relax();
        }

        ret = rnandc_wait_end_of_op(rnandc, chip);
        if (ret)
                return ret;

        return 0;
}

static int rnandc_setup_interface(struct nand_chip *chip, int chipnr,
                                  const struct nand_interface_config *conf)
{
        struct rnand_chip *rnand = to_rnand(chip);
        struct rnandc *rnandc = to_rnandc(chip->controller);
        unsigned int period_ns = 1000000000 / rnandc->ext_clk_rate;
        const struct nand_sdr_timings *sdr;
        unsigned int cyc, cle, ale, bef_dly, ca_to_data;

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

        if (sdr->tRP_min != sdr->tWP_min || sdr->tREH_min != sdr->tWH_min) {
                dev_err(rnandc->dev, "Read and write hold times must be identical\n");
                return -EINVAL;
        }

        if (chipnr < 0)
                return 0;

        rnand->timings_asyn =
                TIMINGS_ASYN_TRWP(TO_CYCLES64(sdr->tRP_min, period_ns)) |
                TIMINGS_ASYN_TRWH(TO_CYCLES64(sdr->tREH_min, period_ns));
        rnand->tim_seq0 =
                TIM_SEQ0_TCCS(TO_CYCLES64(sdr->tCCS_min, period_ns)) |
                TIM_SEQ0_TADL(TO_CYCLES64(sdr->tADL_min, period_ns)) |
                TIM_SEQ0_TRHW(TO_CYCLES64(sdr->tRHW_min, period_ns)) |
                TIM_SEQ0_TWHR(TO_CYCLES64(sdr->tWHR_min, period_ns));
        rnand->tim_seq1 =
                TIM_SEQ1_TWB(TO_CYCLES64(sdr->tWB_max, period_ns)) |
                TIM_SEQ1_TRR(TO_CYCLES64(sdr->tRR_min, period_ns)) |
                TIM_SEQ1_TWW(TO_CYCLES64(sdr->tWW_min, period_ns));

        cyc = sdr->tDS_min + sdr->tDH_min;
        cle = sdr->tCLH_min + sdr->tCLS_min;
        ale = sdr->tALH_min + sdr->tALS_min;
        bef_dly = sdr->tWB_max - sdr->tDH_min;
        ca_to_data = sdr->tWHR_min + sdr->tREA_max - sdr->tDH_min;

        /*
         * D0 = CMD -> ADDR = tCLH + tCLS - 1 cycle
         * D1 = CMD -> CMD = tCLH + tCLS - 1 cycle
         * D2 = CMD -> DLY = tWB - tDH
         * D3 = CMD -> DATA = tWHR + tREA - tDH
         */
        rnand->tim_gen_seq0 =
                TIM_GEN_SEQ0_D0(TO_CYCLES64(cle - cyc, period_ns)) |
                TIM_GEN_SEQ0_D1(TO_CYCLES64(cle - cyc, period_ns)) |
                TIM_GEN_SEQ0_D2(TO_CYCLES64(bef_dly, period_ns)) |
                TIM_GEN_SEQ0_D3(TO_CYCLES64(ca_to_data, period_ns));

        /*
         * D4 = ADDR -> CMD = tALH + tALS - 1 cyle
         * D5 = ADDR -> ADDR = tALH + tALS - 1 cyle
         * D6 = ADDR -> DLY = tWB - tDH
         * D7 = ADDR -> DATA = tWHR + tREA - tDH
         */
        rnand->tim_gen_seq1 =
                TIM_GEN_SEQ1_D4(TO_CYCLES64(ale - cyc, period_ns)) |
                TIM_GEN_SEQ1_D5(TO_CYCLES64(ale - cyc, period_ns)) |
                TIM_GEN_SEQ1_D6(TO_CYCLES64(bef_dly, period_ns)) |
                TIM_GEN_SEQ1_D7(TO_CYCLES64(ca_to_data, period_ns));

        /*
         * D8 = DLY -> DATA = tRR + tREA
         * D9 = DLY -> CMD = tRR
         * D10 = DATA -> CMD = tCLH + tCLS - 1 cycle
         * D11 = DATA -> DLY = tWB - tDH
         */
        rnand->tim_gen_seq2 =
                TIM_GEN_SEQ2_D8(TO_CYCLES64(sdr->tRR_min + sdr->tREA_max, period_ns)) |
                TIM_GEN_SEQ2_D9(TO_CYCLES64(sdr->tRR_min, period_ns)) |
                TIM_GEN_SEQ2_D10(TO_CYCLES64(cle - cyc, period_ns)) |
                TIM_GEN_SEQ2_D11(TO_CYCLES64(bef_dly, period_ns));

        /* D12 = DATA -> END = tCLH - tDH */
        rnand->tim_gen_seq3 =
                TIM_GEN_SEQ3_D12(TO_CYCLES64(sdr->tCLH_min - sdr->tDH_min, period_ns));

        return 0;
}

static int rnandc_ooblayout_ecc(struct mtd_info *mtd, int section,
                                struct mtd_oob_region *oobregion)
{
        struct nand_chip *chip = mtd_to_nand(mtd);
        unsigned int eccbytes = round_up(chip->ecc.bytes, 4) * chip->ecc.steps;

        if (section)
                return -ERANGE;

        oobregion->offset = 2;
        oobregion->length = eccbytes;

        return 0;
}

static int rnandc_ooblayout_free(struct mtd_info *mtd, int section,
                                 struct mtd_oob_region *oobregion)
{
        struct nand_chip *chip = mtd_to_nand(mtd);
        unsigned int eccbytes = round_up(chip->ecc.bytes, 4) * chip->ecc.steps;

        if (section)
                return -ERANGE;

        oobregion->offset = 2 + eccbytes;
        oobregion->length = mtd->oobsize - oobregion->offset;

        return 0;
}

static const struct mtd_ooblayout_ops rnandc_ooblayout_ops = {
        .ecc = rnandc_ooblayout_ecc,
        .free = rnandc_ooblayout_free,
};

static int rnandc_hw_ecc_controller_init(struct nand_chip *chip)
{
        struct rnand_chip *rnand = to_rnand(chip);
        struct mtd_info *mtd = nand_to_mtd(chip);
        struct rnandc *rnandc = to_rnandc(chip->controller);

        if (mtd->writesize > SZ_16K) {
                dev_err(rnandc->dev, "Unsupported page size\n");
                return -EINVAL;
        }

        switch (chip->ecc.size) {
        case SZ_256:
                rnand->control |= CONTROL_ECC_BLOCK_SIZE_256;
                break;
        case SZ_512:
                rnand->control |= CONTROL_ECC_BLOCK_SIZE_512;
                break;
        case SZ_1K:
                rnand->control |= CONTROL_ECC_BLOCK_SIZE_1024;
                break;
        default:
                dev_err(rnandc->dev, "Unsupported ECC chunk size\n");
                return -EINVAL;
        }

        switch (chip->ecc.strength) {
        case 2:
                chip->ecc.bytes = 4;
                rnand->ecc_ctrl |= ECC_CTRL_CAP_2B;
                break;
        case 4:
                chip->ecc.bytes = 7;
                rnand->ecc_ctrl |= ECC_CTRL_CAP_4B;
                break;
        case 8:
                chip->ecc.bytes = 14;
                rnand->ecc_ctrl |= ECC_CTRL_CAP_8B;
                break;
        case 16:
                chip->ecc.bytes = 28;
                rnand->ecc_ctrl |= ECC_CTRL_CAP_16B;
                break;
        case 24:
                chip->ecc.bytes = 42;
                rnand->ecc_ctrl |= ECC_CTRL_CAP_24B;
                break;
        case 32:
                chip->ecc.bytes = 56;
                rnand->ecc_ctrl |= ECC_CTRL_CAP_32B;
                break;
        default:
                dev_err(rnandc->dev, "Unsupported ECC strength\n");
                return -EINVAL;
        }

        rnand->ecc_ctrl |= ECC_CTRL_ERR_THRESHOLD(chip->ecc.strength);

        mtd_set_ooblayout(mtd, &rnandc_ooblayout_ops);
        chip->ecc.steps = mtd->writesize / chip->ecc.size;
        chip->ecc.read_page = rnandc_read_page_hw_ecc;
        chip->ecc.read_subpage = rnandc_read_subpage_hw_ecc;
        chip->ecc.write_page = rnandc_write_page_hw_ecc;
        chip->ecc.write_subpage = rnandc_write_subpage_hw_ecc;

        return 0;
}

static int rnandc_ecc_init(struct nand_chip *chip)
{
        struct nand_ecc_ctrl *ecc = &chip->ecc;
        const struct nand_ecc_props *requirements =
                nanddev_get_ecc_requirements(&chip->base);
        struct rnandc *rnandc = to_rnandc(chip->controller);
        int ret;

        if (ecc->engine_type != NAND_ECC_ENGINE_TYPE_NONE &&
            (!ecc->size || !ecc->strength)) {
                if (requirements->step_size && requirements->strength) {
                        ecc->size = requirements->step_size;
                        ecc->strength = requirements->strength;
                } else {
                        dev_err(rnandc->dev, "No minimum ECC strength\n");
                        return -EINVAL;
                }
        }

        switch (ecc->engine_type) {
        case NAND_ECC_ENGINE_TYPE_ON_HOST:
                ret = rnandc_hw_ecc_controller_init(chip);
                if (ret)
                        return ret;
                break;
        case NAND_ECC_ENGINE_TYPE_NONE:
        case NAND_ECC_ENGINE_TYPE_SOFT:
        case NAND_ECC_ENGINE_TYPE_ON_DIE:
                break;
        default:
                return -EINVAL;
        }

        return 0;
}

static int rnandc_attach_chip(struct nand_chip *chip)
{
        struct rnand_chip *rnand = to_rnand(chip);
        struct rnandc *rnandc = to_rnandc(chip->controller);
        struct mtd_info *mtd = nand_to_mtd(chip);
        struct nand_memory_organization *memorg = nanddev_get_memorg(&chip->base);
        int ret;

        /* Do not store BBT bits in the OOB section as it is not protected */
        if (chip->bbt_options & NAND_BBT_USE_FLASH)
                chip->bbt_options |= NAND_BBT_NO_OOB;

        if (mtd->writesize <= 512) {
                dev_err(rnandc->dev, "Small page devices not supported\n");
                return -EINVAL;
        }

        rnand->control |= CONTROL_CHECK_RB_LINE | CONTROL_INT_EN;

        switch (memorg->pages_per_eraseblock) {
        case 32:
                rnand->control |= CONTROL_BLOCK_SIZE_32P;
                break;
        case 64:
                rnand->control |= CONTROL_BLOCK_SIZE_64P;
                break;
        case 128:
                rnand->control |= CONTROL_BLOCK_SIZE_128P;
                break;
        case 256:
                rnand->control |= CONTROL_BLOCK_SIZE_256P;
                break;
        default:
                dev_err(rnandc->dev, "Unsupported memory organization\n");
                return -EINVAL;
        }

        chip->options |= NAND_SUBPAGE_READ;

        ret = rnandc_ecc_init(chip);
        if (ret) {
                dev_err(rnandc->dev, "ECC initialization failed (%d)\n", ret);
                return ret;
        }

        /* Force an update of the configuration registers */
        rnand->selected_die = -1;

        return 0;
}

static const struct nand_controller_ops rnandc_ops = {
        .attach_chip = rnandc_attach_chip,
        .exec_op = rnandc_exec_op,
        .setup_interface = rnandc_setup_interface,
};

static int rnandc_alloc_dma_buf(struct rnandc *rnandc,
                                struct mtd_info *new_mtd)
{
        unsigned int max_len = new_mtd->writesize + new_mtd->oobsize;
        struct rnand_chip *entry, *temp;
        struct nand_chip *chip;
        struct mtd_info *mtd;

        list_for_each_entry_safe(entry, temp, &rnandc->chips, node) {
                chip = &entry->chip;
                mtd = nand_to_mtd(chip);
                max_len = max(max_len, mtd->writesize + mtd->oobsize);
        }

        if (rnandc->buf && rnandc->buf_sz < max_len) {
                devm_kfree(rnandc->dev, rnandc->buf);
                rnandc->buf = NULL;
        }

        if (!rnandc->buf) {
                rnandc->buf_sz = max_len;
                rnandc->buf = devm_kmalloc(rnandc->dev, max_len,
                                           GFP_KERNEL | GFP_DMA);
                if (!rnandc->buf)
                        return -ENOMEM;
        }

        return 0;
}

static int rnandc_chip_init(struct rnandc *rnandc, struct device_node *np)
{
        struct rnand_chip *rnand;
        struct mtd_info *mtd;
        struct nand_chip *chip;
        int nsels, ret, i;
        u32 cs;

        nsels = of_property_count_elems_of_size(np, "reg", sizeof(u32));
        if (nsels <= 0) {
                ret = (nsels < 0) ? nsels : -EINVAL;
                dev_err(rnandc->dev, "Invalid reg property (%d)\n", ret);
                return ret;
        }

        /* Alloc the driver's NAND chip structure */
        rnand = devm_kzalloc(rnandc->dev, struct_size(rnand, sels, nsels),
                             GFP_KERNEL);
        if (!rnand)
                return -ENOMEM;

        rnand->nsels = nsels;
        rnand->selected_die = -1;

        for (i = 0; i < nsels; i++) {
                ret = of_property_read_u32_index(np, "reg", i, &cs);
                if (ret) {
                        dev_err(rnandc->dev, "Incomplete reg property (%d)\n", ret);
                        return ret;
                }

                if (cs >= RNANDC_CS_NUM) {
                        dev_err(rnandc->dev, "Invalid reg property (%d)\n", cs);
                        return -EINVAL;
                }

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

                /*
                 * No need to check for RB or WP properties, there is a 1:1
                 * mandatory mapping with the CS.
                 */
                rnand->sels[i].cs = cs;
        }

        chip = &rnand->chip;
        chip->controller = &rnandc->controller;
        nand_set_flash_node(chip, np);

        mtd = nand_to_mtd(chip);
        mtd->dev.parent = rnandc->dev;
        if (!mtd->name) {
                dev_err(rnandc->dev, "Missing MTD label\n");
                return -EINVAL;
        }

        ret = nand_scan(chip, rnand->nsels);
        if (ret) {
                dev_err(rnandc->dev, "Failed to scan the NAND chip (%d)\n", ret);
                return ret;
        }

        ret = rnandc_alloc_dma_buf(rnandc, mtd);
        if (ret)
                goto cleanup_nand;

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

        list_add_tail(&rnand->node, &rnandc->chips);

        return 0;

cleanup_nand:
        nand_cleanup(chip);

        return ret;
}

static void rnandc_chips_cleanup(struct rnandc *rnandc)
{
        struct rnand_chip *entry, *temp;
        struct nand_chip *chip;
        int ret;

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

static int rnandc_chips_init(struct rnandc *rnandc)
{
        int ret;

        for_each_child_of_node_scoped(rnandc->dev->of_node, np) {
                ret = rnandc_chip_init(rnandc, np);
                if (ret) {
                        rnandc_chips_cleanup(rnandc);
                        return ret;
                }
        }

        return 0;
}

static int rnandc_probe(struct platform_device *pdev)
{
        struct rnandc *rnandc;
        struct clk *eclk;
        int irq, ret;

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

        rnandc->dev = &pdev->dev;
        nand_controller_init(&rnandc->controller);
        rnandc->controller.ops = &rnandc_ops;
        INIT_LIST_HEAD(&rnandc->chips);
        init_completion(&rnandc->complete);

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

        ret = devm_pm_runtime_enable(&pdev->dev);
        if (ret)
                return ret;

        ret = pm_runtime_resume_and_get(&pdev->dev);
        if (ret < 0)
                return ret;

        /* The external NAND bus clock rate is needed for computing timings */
        eclk = clk_get(&pdev->dev, "eclk");
        if (IS_ERR(eclk)) {
                ret = PTR_ERR(eclk);
                goto dis_runtime_pm;
        }

        rnandc->ext_clk_rate = clk_get_rate(eclk);
        clk_put(eclk);

        rnandc_dis_interrupts(rnandc);
        irq = platform_get_irq_optional(pdev, 0);
        if (irq == -EPROBE_DEFER) {
                ret = irq;
                goto dis_runtime_pm;
        } else if (irq < 0) {
                dev_info(&pdev->dev, "No IRQ found, fallback to polling\n");
                rnandc->use_polling = true;
        } else {
                ret = devm_request_irq(&pdev->dev, irq, rnandc_irq_handler, 0,
                                       "renesas-nand-controller", rnandc);
                if (ret < 0)
                        goto dis_runtime_pm;
        }

        ret = dma_set_mask(&pdev->dev, DMA_BIT_MASK(32));
        if (ret)
                goto dis_runtime_pm;

        rnandc_clear_fifo(rnandc);

        platform_set_drvdata(pdev, rnandc);

        ret = rnandc_chips_init(rnandc);
        if (ret)
                goto dis_runtime_pm;

        return 0;

dis_runtime_pm:
        pm_runtime_put(&pdev->dev);

        return ret;
}

static void rnandc_remove(struct platform_device *pdev)
{
        struct rnandc *rnandc = platform_get_drvdata(pdev);

        rnandc_chips_cleanup(rnandc);

        pm_runtime_put(&pdev->dev);
}

static const struct of_device_id rnandc_id_table[] = {
        { .compatible = "renesas,rcar-gen3-nandc" },
        { .compatible = "renesas,rzn1-nandc" },
        {} /* sentinel */
};
MODULE_DEVICE_TABLE(of, rnandc_id_table);

static struct platform_driver rnandc_driver = {
        .driver = {
                .name = "renesas-nandc",
                .of_match_table = rnandc_id_table,
        },
        .probe = rnandc_probe,
        .remove = rnandc_remove,
};
module_platform_driver(rnandc_driver);

MODULE_AUTHOR("Miquel Raynal <miquel.raynal@bootlin.com>");
MODULE_DESCRIPTION("Renesas R-Car Gen3 & RZ/N1 NAND controller driver");
MODULE_LICENSE("GPL v2");