drivers/mtd/nand/raw/stm32_fmc2_nand.c

// SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause
/*
 * Copyright (C) STMicroelectronics 2019
 * Author: Christophe Kerello <christophe.kerello@st.com>
 */

#include <common.h>
#include <clk.h>
#include <dm.h>
#include <log.h>
#include <nand.h>
#include <reset.h>
#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/iopoll.h>
#include <linux/ioport.h>

/* Bad block marker length */
#define FMC2_BBM_LEN			2

/* ECC step size */
#define FMC2_ECC_STEP_SIZE		512

/* Command delay */
#define FMC2_RB_DELAY_US		30

/* Max chip enable */
#define FMC2_MAX_CE			2

/* Timings */
#define FMC2_THIZ			1
#define FMC2_TIO			8000
#define FMC2_TSYNC			3000
#define FMC2_PCR_TIMING_MASK		0xf
#define FMC2_PMEM_PATT_TIMING_MASK	0xff

/* FMC2 Controller Registers */
#define FMC2_BCR1			0x0
#define FMC2_PCR			0x80
#define FMC2_SR				0x84
#define FMC2_PMEM			0x88
#define FMC2_PATT			0x8c
#define FMC2_HECCR			0x94
#define FMC2_BCHISR			0x254
#define FMC2_BCHICR			0x258
#define FMC2_BCHPBR1			0x260
#define FMC2_BCHPBR2			0x264
#define FMC2_BCHPBR3			0x268
#define FMC2_BCHPBR4			0x26c
#define FMC2_BCHDSR0			0x27c
#define FMC2_BCHDSR1			0x280
#define FMC2_BCHDSR2			0x284
#define FMC2_BCHDSR3			0x288
#define FMC2_BCHDSR4			0x28c

/* Register: FMC2_BCR1 */
#define FMC2_BCR1_FMC2EN		BIT(31)

/* Register: FMC2_PCR */
#define FMC2_PCR_PWAITEN		BIT(1)
#define FMC2_PCR_PBKEN			BIT(2)
#define FMC2_PCR_PWID_MASK		GENMASK(5, 4)
#define FMC2_PCR_PWID(x)		(((x) & 0x3) << 4)
#define FMC2_PCR_PWID_BUSWIDTH_8	0
#define FMC2_PCR_PWID_BUSWIDTH_16	1
#define FMC2_PCR_ECCEN			BIT(6)
#define FMC2_PCR_ECCALG			BIT(8)
#define FMC2_PCR_TCLR_MASK		GENMASK(12, 9)
#define FMC2_PCR_TCLR(x)		(((x) & 0xf) << 9)
#define FMC2_PCR_TCLR_DEFAULT		0xf
#define FMC2_PCR_TAR_MASK		GENMASK(16, 13)
#define FMC2_PCR_TAR(x)			(((x) & 0xf) << 13)
#define FMC2_PCR_TAR_DEFAULT		0xf
#define FMC2_PCR_ECCSS_MASK		GENMASK(19, 17)
#define FMC2_PCR_ECCSS(x)		(((x) & 0x7) << 17)
#define FMC2_PCR_ECCSS_512		1
#define FMC2_PCR_ECCSS_2048		3
#define FMC2_PCR_BCHECC			BIT(24)
#define FMC2_PCR_WEN			BIT(25)

/* Register: FMC2_SR */
#define FMC2_SR_NWRF			BIT(6)

/* Register: FMC2_PMEM */
#define FMC2_PMEM_MEMSET(x)		(((x) & 0xff) << 0)
#define FMC2_PMEM_MEMWAIT(x)		(((x) & 0xff) << 8)
#define FMC2_PMEM_MEMHOLD(x)		(((x) & 0xff) << 16)
#define FMC2_PMEM_MEMHIZ(x)		(((x) & 0xff) << 24)
#define FMC2_PMEM_DEFAULT		0x0a0a0a0a

/* Register: FMC2_PATT */
#define FMC2_PATT_ATTSET(x)		(((x) & 0xff) << 0)
#define FMC2_PATT_ATTWAIT(x)		(((x) & 0xff) << 8)
#define FMC2_PATT_ATTHOLD(x)		(((x) & 0xff) << 16)
#define FMC2_PATT_ATTHIZ(x)		(((x) & 0xff) << 24)
#define FMC2_PATT_DEFAULT		0x0a0a0a0a

/* Register: FMC2_BCHISR */
#define FMC2_BCHISR_DERF		BIT(1)
#define FMC2_BCHISR_EPBRF		BIT(4)

/* Register: FMC2_BCHICR */
#define FMC2_BCHICR_CLEAR_IRQ		GENMASK(4, 0)

/* Register: FMC2_BCHDSR0 */
#define FMC2_BCHDSR0_DUE		BIT(0)
#define FMC2_BCHDSR0_DEF		BIT(1)
#define FMC2_BCHDSR0_DEN_MASK		GENMASK(7, 4)
#define FMC2_BCHDSR0_DEN_SHIFT		4

/* Register: FMC2_BCHDSR1 */
#define FMC2_BCHDSR1_EBP1_MASK		GENMASK(12, 0)
#define FMC2_BCHDSR1_EBP2_MASK		GENMASK(28, 16)
#define FMC2_BCHDSR1_EBP2_SHIFT		16

/* Register: FMC2_BCHDSR2 */
#define FMC2_BCHDSR2_EBP3_MASK		GENMASK(12, 0)
#define FMC2_BCHDSR2_EBP4_MASK		GENMASK(28, 16)
#define FMC2_BCHDSR2_EBP4_SHIFT		16

/* Register: FMC2_BCHDSR3 */
#define FMC2_BCHDSR3_EBP5_MASK		GENMASK(12, 0)
#define FMC2_BCHDSR3_EBP6_MASK		GENMASK(28, 16)
#define FMC2_BCHDSR3_EBP6_SHIFT		16

/* Register: FMC2_BCHDSR4 */
#define FMC2_BCHDSR4_EBP7_MASK		GENMASK(12, 0)
#define FMC2_BCHDSR4_EBP8_MASK		GENMASK(28, 16)
#define FMC2_BCHDSR4_EBP8_SHIFT		16

#define FMC2_NSEC_PER_SEC		1000000000L

enum stm32_fmc2_ecc {
	FMC2_ECC_HAM = 1,
	FMC2_ECC_BCH4 = 4,
	FMC2_ECC_BCH8 = 8
};

struct stm32_fmc2_timings {
	u8 tclr;
	u8 tar;
	u8 thiz;
	u8 twait;
	u8 thold_mem;
	u8 tset_mem;
	u8 thold_att;
	u8 tset_att;
};

struct stm32_fmc2_nand {
	struct nand_chip chip;
	struct stm32_fmc2_timings timings;
	int ncs;
	int cs_used[FMC2_MAX_CE];
};

static inline struct stm32_fmc2_nand *to_fmc2_nand(struct nand_chip *chip)
{
	return container_of(chip, struct stm32_fmc2_nand, chip);
}

struct stm32_fmc2_nfc {
	struct nand_hw_control base;
	struct stm32_fmc2_nand nand;
	struct nand_ecclayout ecclayout;
	void __iomem *io_base;
	void __iomem *data_base[FMC2_MAX_CE];
	void __iomem *cmd_base[FMC2_MAX_CE];
	void __iomem *addr_base[FMC2_MAX_CE];
	struct clk clk;

	u8 cs_assigned;
	int cs_sel;
};

static inline struct stm32_fmc2_nfc *to_stm32_nfc(struct nand_hw_control *base)
{
	return container_of(base, struct stm32_fmc2_nfc, base);
}

static void stm32_fmc2_timings_init(struct nand_chip *chip)
{
	struct stm32_fmc2_nfc *fmc2 = to_stm32_nfc(chip->controller);
	struct stm32_fmc2_nand *nand = to_fmc2_nand(chip);
	struct stm32_fmc2_timings *timings = &nand->timings;
	u32 pcr = readl(fmc2->io_base + FMC2_PCR);
	u32 pmem, patt;

	/* Set tclr/tar timings */
	pcr &= ~FMC2_PCR_TCLR_MASK;
	pcr |= FMC2_PCR_TCLR(timings->tclr);
	pcr &= ~FMC2_PCR_TAR_MASK;
	pcr |= FMC2_PCR_TAR(timings->tar);

	/* Set tset/twait/thold/thiz timings in common bank */
	pmem = FMC2_PMEM_MEMSET(timings->tset_mem);
	pmem |= FMC2_PMEM_MEMWAIT(timings->twait);
	pmem |= FMC2_PMEM_MEMHOLD(timings->thold_mem);
	pmem |= FMC2_PMEM_MEMHIZ(timings->thiz);

	/* Set tset/twait/thold/thiz timings in attribut bank */
	patt = FMC2_PATT_ATTSET(timings->tset_att);
	patt |= FMC2_PATT_ATTWAIT(timings->twait);
	patt |= FMC2_PATT_ATTHOLD(timings->thold_att);
	patt |= FMC2_PATT_ATTHIZ(timings->thiz);

	writel(pcr, fmc2->io_base + FMC2_PCR);
	writel(pmem, fmc2->io_base + FMC2_PMEM);
	writel(patt, fmc2->io_base + FMC2_PATT);
}

static void stm32_fmc2_setup(struct nand_chip *chip)
{
	struct stm32_fmc2_nfc *fmc2 = to_stm32_nfc(chip->controller);
	u32 pcr = readl(fmc2->io_base + FMC2_PCR);

	/* Configure ECC algorithm (default configuration is Hamming) */
	pcr &= ~FMC2_PCR_ECCALG;
	pcr &= ~FMC2_PCR_BCHECC;
	if (chip->ecc.strength == FMC2_ECC_BCH8) {
		pcr |= FMC2_PCR_ECCALG;
		pcr |= FMC2_PCR_BCHECC;
	} else if (chip->ecc.strength == FMC2_ECC_BCH4) {
		pcr |= FMC2_PCR_ECCALG;
	}

	/* Set buswidth */
	pcr &= ~FMC2_PCR_PWID_MASK;
	if (chip->options & NAND_BUSWIDTH_16)
		pcr |= FMC2_PCR_PWID(FMC2_PCR_PWID_BUSWIDTH_16);

	/* Set ECC sector size */
	pcr &= ~FMC2_PCR_ECCSS_MASK;
	pcr |= FMC2_PCR_ECCSS(FMC2_PCR_ECCSS_512);

	writel(pcr, fmc2->io_base + FMC2_PCR);
}

static void stm32_fmc2_select_chip(struct mtd_info *mtd, int chipnr)
{
	struct nand_chip *chip = mtd_to_nand(mtd);
	struct stm32_fmc2_nfc *fmc2 = to_stm32_nfc(chip->controller);
	struct stm32_fmc2_nand *nand = to_fmc2_nand(chip);

	if (chipnr < 0 || chipnr >= nand->ncs)
		return;

	if (nand->cs_used[chipnr] == fmc2->cs_sel)
		return;

	fmc2->cs_sel = nand->cs_used[chipnr];
	chip->IO_ADDR_R = fmc2->data_base[fmc2->cs_sel];
	chip->IO_ADDR_W = fmc2->data_base[fmc2->cs_sel];

	stm32_fmc2_setup(chip);
	stm32_fmc2_timings_init(chip);
}

static void stm32_fmc2_set_buswidth_16(struct stm32_fmc2_nfc *fmc2, bool set)
{
	u32 pcr = readl(fmc2->io_base + FMC2_PCR);

	pcr &= ~FMC2_PCR_PWID_MASK;
	if (set)
		pcr |= FMC2_PCR_PWID(FMC2_PCR_PWID_BUSWIDTH_16);
	writel(pcr, fmc2->io_base + FMC2_PCR);
}

static void stm32_fmc2_set_ecc(struct stm32_fmc2_nfc *fmc2, bool enable)
{
	u32 pcr = readl(fmc2->io_base + FMC2_PCR);

	pcr &= ~FMC2_PCR_ECCEN;
	if (enable)
		pcr |= FMC2_PCR_ECCEN;
	writel(pcr, fmc2->io_base + FMC2_PCR);
}

static inline void stm32_fmc2_clear_bch_irq(struct stm32_fmc2_nfc *fmc2)
{
	writel(FMC2_BCHICR_CLEAR_IRQ, fmc2->io_base + FMC2_BCHICR);
}

static void stm32_fmc2_cmd_ctrl(struct mtd_info *mtd, int cmd,
				unsigned int ctrl)
{
	struct nand_chip *chip = mtd_to_nand(mtd);
	struct stm32_fmc2_nfc *fmc2 = to_stm32_nfc(chip->controller);

	if (cmd == NAND_CMD_NONE)
		return;

	if (ctrl & NAND_CLE) {
		writeb(cmd, fmc2->cmd_base[fmc2->cs_sel]);
		return;
	}

	writeb(cmd, fmc2->addr_base[fmc2->cs_sel]);
}

/*
 * Enable ECC logic and reset syndrome/parity bits previously calculated
 * Syndrome/parity bits is cleared by setting the ECCEN bit to 0
 */
static void stm32_fmc2_hwctl(struct mtd_info *mtd, int mode)
{
	struct nand_chip *chip = mtd_to_nand(mtd);
	struct stm32_fmc2_nfc *fmc2 = to_stm32_nfc(chip->controller);

	stm32_fmc2_set_ecc(fmc2, false);

	if (chip->ecc.strength != FMC2_ECC_HAM) {
		u32 pcr = readl(fmc2->io_base + FMC2_PCR);

		if (mode == NAND_ECC_WRITE)
			pcr |= FMC2_PCR_WEN;
		else
			pcr &= ~FMC2_PCR_WEN;
		writel(pcr, fmc2->io_base + FMC2_PCR);

		stm32_fmc2_clear_bch_irq(fmc2);
	}

	stm32_fmc2_set_ecc(fmc2, true);
}

/*
 * ECC Hamming calculation
 * ECC is 3 bytes for 512 bytes of data (supports error correction up to
 * max of 1-bit)
 */
static int stm32_fmc2_ham_calculate(struct mtd_info *mtd, const u8 *data,
				    u8 *ecc)
{
	struct nand_chip *chip = mtd_to_nand(mtd);
	struct stm32_fmc2_nfc *fmc2 = to_stm32_nfc(chip->controller);
	u32 heccr, sr;
	int ret;

	ret = readl_poll_timeout(fmc2->io_base + FMC2_SR, sr,
				 sr & FMC2_SR_NWRF, 10000);
	if (ret < 0) {
		pr_err("Ham timeout\n");
		return ret;
	}

	heccr = readl(fmc2->io_base + FMC2_HECCR);

	ecc[0] = heccr;
	ecc[1] = heccr >> 8;
	ecc[2] = heccr >> 16;

	stm32_fmc2_set_ecc(fmc2, false);

	return 0;
}

static int stm32_fmc2_ham_correct(struct mtd_info *mtd, u8 *dat,
				  u8 *read_ecc, u8 *calc_ecc)
{
	u8 bit_position = 0, b0, b1, b2;
	u32 byte_addr = 0, b;
	u32 i, shifting = 1;

	/* Indicate which bit and byte is faulty (if any) */
	b0 = read_ecc[0] ^ calc_ecc[0];
	b1 = read_ecc[1] ^ calc_ecc[1];
	b2 = read_ecc[2] ^ calc_ecc[2];
	b = b0 | (b1 << 8) | (b2 << 16);

	/* No errors */
	if (likely(!b))
		return 0;

	/* Calculate bit position */
	for (i = 0; i < 3; i++) {
		switch (b % 4) {
		case 2:
			bit_position += shifting;
		case 1:
			break;
		default:
			return -EBADMSG;
		}
		shifting <<= 1;
		b >>= 2;
	}

	/* Calculate byte position */
	shifting = 1;
	for (i = 0; i < 9; i++) {
		switch (b % 4) {
		case 2:
			byte_addr += shifting;
		case 1:
			break;
		default:
			return -EBADMSG;
		}
		shifting <<= 1;
		b >>= 2;
	}

	/* Flip the bit */
	dat[byte_addr] ^= (1 << bit_position);

	return 1;
}

/*
 * ECC BCH calculation and correction
 * ECC is 7/13 bytes for 512 bytes of data (supports error correction up to
 * max of 4-bit/8-bit)
 */

static int stm32_fmc2_bch_calculate(struct mtd_info *mtd, const u8 *data,
				    u8 *ecc)
{
	struct nand_chip *chip = mtd_to_nand(mtd);
	struct stm32_fmc2_nfc *fmc2 = to_stm32_nfc(chip->controller);
	u32 bchpbr, bchisr;
	int ret;

	/* Wait until the BCH code is ready */
	ret = readl_poll_timeout(fmc2->io_base + FMC2_BCHISR, bchisr,
				 bchisr & FMC2_BCHISR_EPBRF, 10000);
	if (ret < 0) {
		pr_err("Bch timeout\n");
		return ret;
	}

	/* Read parity bits */
	bchpbr = readl(fmc2->io_base + FMC2_BCHPBR1);
	ecc[0] = bchpbr;
	ecc[1] = bchpbr >> 8;
	ecc[2] = bchpbr >> 16;
	ecc[3] = bchpbr >> 24;

	bchpbr = readl(fmc2->io_base + FMC2_BCHPBR2);
	ecc[4] = bchpbr;
	ecc[5] = bchpbr >> 8;
	ecc[6] = bchpbr >> 16;

	if (chip->ecc.strength == FMC2_ECC_BCH8) {
		ecc[7] = bchpbr >> 24;

		bchpbr = readl(fmc2->io_base + FMC2_BCHPBR3);
		ecc[8] = bchpbr;
		ecc[9] = bchpbr >> 8;
		ecc[10] = bchpbr >> 16;
		ecc[11] = bchpbr >> 24;

		bchpbr = readl(fmc2->io_base + FMC2_BCHPBR4);
		ecc[12] = bchpbr;
	}

	stm32_fmc2_set_ecc(fmc2, false);

	return 0;
}

static int stm32_fmc2_bch_correct(struct mtd_info *mtd, u8 *dat,
				  u8 *read_ecc, u8 *calc_ecc)
{
	struct nand_chip *chip = mtd_to_nand(mtd);
	struct stm32_fmc2_nfc *fmc2 = to_stm32_nfc(chip->controller);
	u32 bchdsr0, bchdsr1, bchdsr2, bchdsr3, bchdsr4, bchisr;
	u16 pos[8];
	int i, ret, den, eccsize = chip->ecc.size;
	unsigned int nb_errs = 0;

	/* Wait until the decoding error is ready */
	ret = readl_poll_timeout(fmc2->io_base + FMC2_BCHISR, bchisr,
				 bchisr & FMC2_BCHISR_DERF, 10000);
	if (ret < 0) {
		pr_err("Bch timeout\n");
		return ret;
	}

	bchdsr0 = readl(fmc2->io_base + FMC2_BCHDSR0);
	bchdsr1 = readl(fmc2->io_base + FMC2_BCHDSR1);
	bchdsr2 = readl(fmc2->io_base + FMC2_BCHDSR2);
	bchdsr3 = readl(fmc2->io_base + FMC2_BCHDSR3);
	bchdsr4 = readl(fmc2->io_base + FMC2_BCHDSR4);

	stm32_fmc2_set_ecc(fmc2, false);

	/* No errors found */
	if (likely(!(bchdsr0 & FMC2_BCHDSR0_DEF)))
		return 0;

	/* Too many errors detected */
	if (unlikely(bchdsr0 & FMC2_BCHDSR0_DUE))
		return -EBADMSG;

	pos[0] = bchdsr1 & FMC2_BCHDSR1_EBP1_MASK;
	pos[1] = (bchdsr1 & FMC2_BCHDSR1_EBP2_MASK) >> FMC2_BCHDSR1_EBP2_SHIFT;
	pos[2] = bchdsr2 & FMC2_BCHDSR2_EBP3_MASK;
	pos[3] = (bchdsr2 & FMC2_BCHDSR2_EBP4_MASK) >> FMC2_BCHDSR2_EBP4_SHIFT;
	pos[4] = bchdsr3 & FMC2_BCHDSR3_EBP5_MASK;
	pos[5] = (bchdsr3 & FMC2_BCHDSR3_EBP6_MASK) >> FMC2_BCHDSR3_EBP6_SHIFT;
	pos[6] = bchdsr4 & FMC2_BCHDSR4_EBP7_MASK;
	pos[7] = (bchdsr4 & FMC2_BCHDSR4_EBP8_MASK) >> FMC2_BCHDSR4_EBP8_SHIFT;

	den = (bchdsr0 & FMC2_BCHDSR0_DEN_MASK) >> FMC2_BCHDSR0_DEN_SHIFT;
	for (i = 0; i < den; i++) {
		if (pos[i] < eccsize * 8) {
			__change_bit(pos[i], (unsigned long *)dat);
			nb_errs++;
		}
	}

	return nb_errs;
}

static int stm32_fmc2_read_page(struct mtd_info *mtd,
				struct nand_chip *chip, u8 *buf,
				int oob_required, int page)
{
	int i, s, stat, eccsize = chip->ecc.size;
	int eccbytes = chip->ecc.bytes;
	int eccsteps = chip->ecc.steps;
	int eccstrength = chip->ecc.strength;
	u8 *p = buf;
	u8 *ecc_calc = chip->buffers->ecccalc;
	u8 *ecc_code = chip->buffers->ecccode;
	unsigned int max_bitflips = 0;

	for (i = mtd->writesize + FMC2_BBM_LEN, s = 0; s < eccsteps;
	     s++, i += eccbytes, p += eccsize) {
		chip->ecc.hwctl(mtd, NAND_ECC_READ);

		/* Read the nand page sector (512 bytes) */
		chip->cmdfunc(mtd, NAND_CMD_RNDOUT, s * eccsize, -1);
		chip->read_buf(mtd, p, eccsize);

		/* Read the corresponding ECC bytes */
		chip->cmdfunc(mtd, NAND_CMD_RNDOUT, i, -1);
		chip->read_buf(mtd, ecc_code, eccbytes);

		/* Correct the data */
		stat = chip->ecc.correct(mtd, p, ecc_code, ecc_calc);
		if (stat == -EBADMSG)
			/* Check for empty pages with bitflips */
			stat = nand_check_erased_ecc_chunk(p, eccsize,
							   ecc_code, eccbytes,
							   NULL, 0,
							   eccstrength);

		if (stat < 0) {
			mtd->ecc_stats.failed++;
		} else {
			mtd->ecc_stats.corrected += stat;
			max_bitflips = max_t(unsigned int, max_bitflips, stat);
		}
	}

	/* Read oob */
	if (oob_required) {
		chip->cmdfunc(mtd, NAND_CMD_RNDOUT, mtd->writesize, -1);
		chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
	}

	return max_bitflips;
}

static void stm32_fmc2_init(struct stm32_fmc2_nfc *fmc2)
{
	u32 pcr = readl(fmc2->io_base + FMC2_PCR);
	u32 bcr1 = readl(fmc2->io_base + FMC2_BCR1);

	/* Set CS used to undefined */
	fmc2->cs_sel = -1;

	/* Enable wait feature and nand flash memory bank */
	pcr |= FMC2_PCR_PWAITEN;
	pcr |= FMC2_PCR_PBKEN;

	/* Set buswidth to 8 bits mode for identification */
	pcr &= ~FMC2_PCR_PWID_MASK;

	/* ECC logic is disabled */
	pcr &= ~FMC2_PCR_ECCEN;

	/* Default mode */
	pcr &= ~FMC2_PCR_ECCALG;
	pcr &= ~FMC2_PCR_BCHECC;
	pcr &= ~FMC2_PCR_WEN;

	/* Set default ECC sector size */
	pcr &= ~FMC2_PCR_ECCSS_MASK;
	pcr |= FMC2_PCR_ECCSS(FMC2_PCR_ECCSS_2048);

	/* Set default tclr/tar timings */
	pcr &= ~FMC2_PCR_TCLR_MASK;
	pcr |= FMC2_PCR_TCLR(FMC2_PCR_TCLR_DEFAULT);
	pcr &= ~FMC2_PCR_TAR_MASK;
	pcr |= FMC2_PCR_TAR(FMC2_PCR_TAR_DEFAULT);

	/* Enable FMC2 controller */
	bcr1 |= FMC2_BCR1_FMC2EN;

	writel(bcr1, fmc2->io_base + FMC2_BCR1);
	writel(pcr, fmc2->io_base + FMC2_PCR);
	writel(FMC2_PMEM_DEFAULT, fmc2->io_base + FMC2_PMEM);
	writel(FMC2_PATT_DEFAULT, fmc2->io_base + FMC2_PATT);
}

static void stm32_fmc2_calc_timings(struct nand_chip *chip,
				    const struct nand_sdr_timings *sdrt)
{
	struct stm32_fmc2_nfc *fmc2 = to_stm32_nfc(chip->controller);
	struct stm32_fmc2_nand *nand = to_fmc2_nand(chip);
	struct stm32_fmc2_timings *tims = &nand->timings;
	unsigned long hclk = clk_get_rate(&fmc2->clk);
	unsigned long hclkp = FMC2_NSEC_PER_SEC / (hclk / 1000);
	unsigned long timing, tar, tclr, thiz, twait;
	unsigned long tset_mem, tset_att, thold_mem, thold_att;

	tar = max_t(unsigned long, hclkp, sdrt->tAR_min);
	timing = DIV_ROUND_UP(tar, hclkp) - 1;
	tims->tar = min_t(unsigned long, timing, FMC2_PCR_TIMING_MASK);

	tclr = max_t(unsigned long, hclkp, sdrt->tCLR_min);
	timing = DIV_ROUND_UP(tclr, hclkp) - 1;
	tims->tclr = min_t(unsigned long, timing, FMC2_PCR_TIMING_MASK);

	tims->thiz = FMC2_THIZ;
	thiz = (tims->thiz + 1) * hclkp;

	/*
	 * tWAIT > tRP
	 * tWAIT > tWP
	 * tWAIT > tREA + tIO
	 */
	twait = max_t(unsigned long, hclkp, sdrt->tRP_min);
	twait = max_t(unsigned long, twait, sdrt->tWP_min);
	twait = max_t(unsigned long, twait, sdrt->tREA_max + FMC2_TIO);
	timing = DIV_ROUND_UP(twait, hclkp);
	tims->twait = clamp_val(timing, 1, FMC2_PMEM_PATT_TIMING_MASK);

	/*
	 * tSETUP_MEM > tCS - tWAIT
	 * tSETUP_MEM > tALS - tWAIT
	 * tSETUP_MEM > tDS - (tWAIT - tHIZ)
	 */
	tset_mem = hclkp;
	if (sdrt->tCS_min > twait && (tset_mem < sdrt->tCS_min - twait))
		tset_mem = sdrt->tCS_min - twait;
	if (sdrt->tALS_min > twait && (tset_mem < sdrt->tALS_min - twait))
		tset_mem = sdrt->tALS_min - twait;
	if (twait > thiz && (sdrt->tDS_min > twait - thiz) &&
	    (tset_mem < sdrt->tDS_min - (twait - thiz)))
		tset_mem = sdrt->tDS_min - (twait - thiz);
	timing = DIV_ROUND_UP(tset_mem, hclkp);
	tims->tset_mem = clamp_val(timing, 1, FMC2_PMEM_PATT_TIMING_MASK);

	/*
	 * tHOLD_MEM > tCH
	 * tHOLD_MEM > tREH - tSETUP_MEM
	 * tHOLD_MEM > max(tRC, tWC) - (tSETUP_MEM + tWAIT)
	 */
	thold_mem = max_t(unsigned long, hclkp, sdrt->tCH_min);
	if (sdrt->tREH_min > tset_mem &&
	    (thold_mem < sdrt->tREH_min - tset_mem))
		thold_mem = sdrt->tREH_min - tset_mem;
	if ((sdrt->tRC_min > tset_mem + twait) &&
	    (thold_mem < sdrt->tRC_min - (tset_mem + twait)))
		thold_mem = sdrt->tRC_min - (tset_mem + twait);
	if ((sdrt->tWC_min > tset_mem + twait) &&
	    (thold_mem < sdrt->tWC_min - (tset_mem + twait)))
		thold_mem = sdrt->tWC_min - (tset_mem + twait);
	timing = DIV_ROUND_UP(thold_mem, hclkp);
	tims->thold_mem = clamp_val(timing, 1, FMC2_PMEM_PATT_TIMING_MASK);

	/*
	 * tSETUP_ATT > tCS - tWAIT
	 * tSETUP_ATT > tCLS - tWAIT
	 * tSETUP_ATT > tALS - tWAIT
	 * tSETUP_ATT > tRHW - tHOLD_MEM
	 * tSETUP_ATT > tDS - (tWAIT - tHIZ)
	 */
	tset_att = hclkp;
	if (sdrt->tCS_min > twait && (tset_att < sdrt->tCS_min - twait))
		tset_att = sdrt->tCS_min - twait;
	if (sdrt->tCLS_min > twait && (tset_att < sdrt->tCLS_min - twait))
		tset_att = sdrt->tCLS_min - twait;
	if (sdrt->tALS_min > twait && (tset_att < sdrt->tALS_min - twait))
		tset_att = sdrt->tALS_min - twait;
	if (sdrt->tRHW_min > thold_mem &&
	    (tset_att < sdrt->tRHW_min - thold_mem))
		tset_att = sdrt->tRHW_min - thold_mem;
	if (twait > thiz && (sdrt->tDS_min > twait - thiz) &&
	    (tset_att < sdrt->tDS_min - (twait - thiz)))
		tset_att = sdrt->tDS_min - (twait - thiz);
	timing = DIV_ROUND_UP(tset_att, hclkp);
	tims->tset_att = clamp_val(timing, 1, FMC2_PMEM_PATT_TIMING_MASK);

	/*
	 * tHOLD_ATT > tALH
	 * tHOLD_ATT > tCH
	 * tHOLD_ATT > tCLH
	 * tHOLD_ATT > tCOH
	 * tHOLD_ATT > tDH
	 * tHOLD_ATT > tWB + tIO + tSYNC - tSETUP_MEM
	 * tHOLD_ATT > tADL - tSETUP_MEM
	 * tHOLD_ATT > tWH - tSETUP_MEM
	 * tHOLD_ATT > tWHR - tSETUP_MEM
	 * tHOLD_ATT > tRC - (tSETUP_ATT + tWAIT)
	 * tHOLD_ATT > tWC - (tSETUP_ATT + tWAIT)
	 */
	thold_att = max_t(unsigned long, hclkp, sdrt->tALH_min);
	thold_att = max_t(unsigned long, thold_att, sdrt->tCH_min);
	thold_att = max_t(unsigned long, thold_att, sdrt->tCLH_min);
	thold_att = max_t(unsigned long, thold_att, sdrt->tCOH_min);
	thold_att = max_t(unsigned long, thold_att, sdrt->tDH_min);
	if ((sdrt->tWB_max + FMC2_TIO + FMC2_TSYNC > tset_mem) &&
	    (thold_att < sdrt->tWB_max + FMC2_TIO + FMC2_TSYNC - tset_mem))
		thold_att = sdrt->tWB_max + FMC2_TIO + FMC2_TSYNC - tset_mem;
	if (sdrt->tADL_min > tset_mem &&
	    (thold_att < sdrt->tADL_min - tset_mem))
		thold_att = sdrt->tADL_min - tset_mem;
	if (sdrt->tWH_min > tset_mem &&
	    (thold_att < sdrt->tWH_min - tset_mem))
		thold_att = sdrt->tWH_min - tset_mem;
	if (sdrt->tWHR_min > tset_mem &&
	    (thold_att < sdrt->tWHR_min - tset_mem))
		thold_att = sdrt->tWHR_min - tset_mem;
	if ((sdrt->tRC_min > tset_att + twait) &&
	    (thold_att < sdrt->tRC_min - (tset_att + twait)))
		thold_att = sdrt->tRC_min - (tset_att + twait);
	if ((sdrt->tWC_min > tset_att + twait) &&
	    (thold_att < sdrt->tWC_min - (tset_att + twait)))
		thold_att = sdrt->tWC_min - (tset_att + twait);
	timing = DIV_ROUND_UP(thold_att, hclkp);
	tims->thold_att = clamp_val(timing, 1, FMC2_PMEM_PATT_TIMING_MASK);
}

static int stm32_fmc2_setup_interface(struct mtd_info *mtd, int chipnr,
				      const struct nand_data_interface *conf)
{
	struct nand_chip *chip = mtd_to_nand(mtd);
	const struct nand_sdr_timings *sdrt;

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

	if (chipnr == NAND_DATA_IFACE_CHECK_ONLY)
		return 0;

	stm32_fmc2_calc_timings(chip, sdrt);

	stm32_fmc2_timings_init(chip);

	return 0;
}

static void stm32_fmc2_nand_callbacks_setup(struct nand_chip *chip)
{
	chip->ecc.hwctl = stm32_fmc2_hwctl;

	/*
	 * Specific callbacks to read/write a page depending on
	 * the algo used (Hamming, BCH).
	 */
	if (chip->ecc.strength == FMC2_ECC_HAM) {
		/* Hamming is used */
		chip->ecc.calculate = stm32_fmc2_ham_calculate;
		chip->ecc.correct = stm32_fmc2_ham_correct;
		chip->ecc.bytes = chip->options & NAND_BUSWIDTH_16 ? 4 : 3;
		chip->ecc.options |= NAND_ECC_GENERIC_ERASED_CHECK;
		return;
	}

	/* BCH is used */
	chip->ecc.read_page = stm32_fmc2_read_page;
	chip->ecc.calculate = stm32_fmc2_bch_calculate;
	chip->ecc.correct = stm32_fmc2_bch_correct;

	if (chip->ecc.strength == FMC2_ECC_BCH8)
		chip->ecc.bytes = chip->options & NAND_BUSWIDTH_16 ? 14 : 13;
	else
		chip->ecc.bytes = chip->options & NAND_BUSWIDTH_16 ? 8 : 7;
}

static int stm32_fmc2_calc_ecc_bytes(int step_size, int strength)
{
	/* Hamming */
	if (strength == FMC2_ECC_HAM)
		return 4;

	/* BCH8 */
	if (strength == FMC2_ECC_BCH8)
		return 14;

	/* BCH4 */
	return 8;
}

NAND_ECC_CAPS_SINGLE(stm32_fmc2_ecc_caps, stm32_fmc2_calc_ecc_bytes,
		     FMC2_ECC_STEP_SIZE,
		     FMC2_ECC_HAM, FMC2_ECC_BCH4, FMC2_ECC_BCH8);

static int stm32_fmc2_parse_child(struct stm32_fmc2_nfc *fmc2,
				  ofnode node)
{
	struct stm32_fmc2_nand *nand = &fmc2->nand;
	u32 cs[FMC2_MAX_CE];
	int ret, i;

	if (!ofnode_get_property(node, "reg", &nand->ncs))
		return -EINVAL;

	nand->ncs /= sizeof(u32);
	if (!nand->ncs) {
		pr_err("Invalid reg property size\n");
		return -EINVAL;
	}

	ret = ofnode_read_u32_array(node, "reg", cs, nand->ncs);
	if (ret < 0) {
		pr_err("Could not retrieve reg property\n");
		return -EINVAL;
	}

	for (i = 0; i < nand->ncs; i++) {
		if (cs[i] >= FMC2_MAX_CE) {
			pr_err("Invalid reg value: %d\n",
			       nand->cs_used[i]);
			return -EINVAL;
		}

		if (fmc2->cs_assigned & BIT(cs[i])) {
			pr_err("Cs already assigned: %d\n",
			       nand->cs_used[i]);
			return -EINVAL;
		}

		fmc2->cs_assigned |= BIT(cs[i]);
		nand->cs_used[i] = cs[i];
	}

	nand->chip.flash_node = ofnode_to_offset(node);

	return 0;
}

static int stm32_fmc2_parse_dt(struct udevice *dev,
			       struct stm32_fmc2_nfc *fmc2)
{
	ofnode child;
	int ret, nchips = 0;

	dev_for_each_subnode(child, dev)
		nchips++;

	if (!nchips) {
		pr_err("NAND chip not defined\n");
		return -EINVAL;
	}

	if (nchips > 1) {
		pr_err("Too many NAND chips defined\n");
		return -EINVAL;
	}

	dev_for_each_subnode(child, dev) {
		ret = stm32_fmc2_parse_child(fmc2, child);
		if (ret)
			return ret;
	}

	return 0;
}

static int stm32_fmc2_probe(struct udevice *dev)
{
	struct stm32_fmc2_nfc *fmc2 = dev_get_priv(dev);
	struct stm32_fmc2_nand *nand = &fmc2->nand;
	struct nand_chip *chip = &nand->chip;
	struct mtd_info *mtd = &chip->mtd;
	struct nand_ecclayout *ecclayout;
	struct resource resource;
	struct reset_ctl reset;
	int oob_index, chip_cs, mem_region, ret;
	unsigned int i;

	spin_lock_init(&fmc2->controller.lock);
	init_waitqueue_head(&fmc2->controller.wq);

	ret = stm32_fmc2_parse_dt(dev, fmc2);
	if (ret)
		return ret;

	/* Get resources */
	ret = dev_read_resource(dev, 0, &resource);
	if (ret) {
		pr_err("Resource io_base not found");
		return ret;
	}
	fmc2->io_base = (void __iomem *)resource.start;

	for (chip_cs = 0, mem_region = 1; chip_cs < FMC2_MAX_CE;
	     chip_cs++, mem_region += 3) {
		if (!(fmc2->cs_assigned & BIT(chip_cs)))
			continue;

		ret = dev_read_resource(dev, mem_region, &resource);
		if (ret) {
			pr_err("Resource data_base not found for cs%d",
			       chip_cs);
			return ret;
		}
		fmc2->data_base[chip_cs] = (void __iomem *)resource.start;

		ret = dev_read_resource(dev, mem_region + 1, &resource);
		if (ret) {
			pr_err("Resource cmd_base not found for cs%d",
			       chip_cs);
			return ret;
		}
		fmc2->cmd_base[chip_cs] = (void __iomem *)resource.start;

		ret = dev_read_resource(dev, mem_region + 2, &resource);
		if (ret) {
			pr_err("Resource addr_base not found for cs%d",
			       chip_cs);
			return ret;
		}
		fmc2->addr_base[chip_cs] = (void __iomem *)resource.start;
	}

	/* Enable the clock */
	ret = clk_get_by_index(dev, 0, &fmc2->clk);
	if (ret)
		return ret;

	ret = clk_enable(&fmc2->clk);
	if (ret)
		return ret;

	/* Reset */
	ret = reset_get_by_index(dev, 0, &reset);
	if (!ret) {
		reset_assert(&reset);
		udelay(2);
		reset_deassert(&reset);
	}

	stm32_fmc2_init(fmc2);

	chip->controller = &fmc2->base;
	chip->select_chip = stm32_fmc2_select_chip;
	chip->setup_data_interface = stm32_fmc2_setup_interface;
	chip->cmd_ctrl = stm32_fmc2_cmd_ctrl;
	chip->chip_delay = FMC2_RB_DELAY_US;
	chip->options |= NAND_BUSWIDTH_AUTO | NAND_NO_SUBPAGE_WRITE |
			 NAND_USE_BOUNCE_BUFFER;

	/* Default ECC settings */
	chip->ecc.mode = NAND_ECC_HW;
	chip->ecc.size = FMC2_ECC_STEP_SIZE;
	chip->ecc.strength = FMC2_ECC_BCH8;

	ret = nand_scan_ident(mtd, nand->ncs, NULL);
	if (ret)
		return ret;

	/*
	 * Only NAND_ECC_HW mode is actually supported
	 * Hamming => ecc.strength = 1
	 * BCH4 => ecc.strength = 4
	 * BCH8 => ecc.strength = 8
	 * ECC sector size = 512
	 */
	if (chip->ecc.mode != NAND_ECC_HW) {
		pr_err("Nand_ecc_mode is not well defined in the DT\n");
		return -EINVAL;
	}

	ret = nand_check_ecc_caps(chip, &stm32_fmc2_ecc_caps,
				  mtd->oobsize - FMC2_BBM_LEN);
	if (ret) {
		pr_err("No valid ECC settings set\n");
		return ret;
	}

	if (chip->bbt_options & NAND_BBT_USE_FLASH)
		chip->bbt_options |= NAND_BBT_NO_OOB;

	stm32_fmc2_nand_callbacks_setup(chip);

	/* Define ECC layout */
	ecclayout = &fmc2->ecclayout;
	ecclayout->eccbytes = chip->ecc.bytes *
			      (mtd->writesize / chip->ecc.size);
	oob_index = FMC2_BBM_LEN;
	for (i = 0; i < ecclayout->eccbytes; i++, oob_index++)
		ecclayout->eccpos[i] = oob_index;
	ecclayout->oobfree->offset = oob_index;
	ecclayout->oobfree->length = mtd->oobsize - ecclayout->oobfree->offset;
	chip->ecc.layout = ecclayout;

	if (chip->options & NAND_BUSWIDTH_16)
		stm32_fmc2_set_buswidth_16(fmc2, true);

	ret = nand_scan_tail(mtd);
	if (ret)
		return ret;

	return nand_register(0, mtd);
}

static const struct udevice_id stm32_fmc2_match[] = {
	{ .compatible = "st,stm32mp15-fmc2" },
	{ /* Sentinel */ }
};

U_BOOT_DRIVER(stm32_fmc2_nand) = {
	.name = "stm32_fmc2_nand",
	.id = UCLASS_MTD,
	.of_match = stm32_fmc2_match,
	.probe = stm32_fmc2_probe,
	.priv_auto_alloc_size = sizeof(struct stm32_fmc2_nfc),
};

void board_nand_init(void)
{
	struct udevice *dev;
	int ret;

	ret = uclass_get_device_by_driver(UCLASS_MTD,
					  DM_GET_DRIVER(stm32_fmc2_nand),
					  &dev);
	if (ret && ret != -ENODEV)
		pr_err("Failed to initialize STM32 FMC2 NAND controller. (error %d)\n",
		       ret);
}