// SPDX-License-Identifier: GPL-2.0
/*
 * Arasan NAND Flash Controller Driver
 *
 * Copyright (C) 2014 - 2020 Xilinx, Inc.
 * Author:
 *   Miquel Raynal <miquel.raynal@bootlin.com>
 * Original work (fully rewritten):
 *   Punnaiah Choudary Kalluri <punnaia@xilinx.com>
 *   Naga Sureshkumar Relli <nagasure@xilinx.com>
 */

#include <linux/bch.h>
#include <linux/bitfield.h>
#include <linux/clk.h>
#include <linux/delay.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/partitions.h>
#include <linux/mtd/rawnand.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#define PKT_REG				0x00
#define   PKT_SIZE(x)			FIELD_PREP(GENMASK(10, 0), (x))
#define   PKT_STEPS(x)			FIELD_PREP(GENMASK(23, 12), (x))

#define MEM_ADDR1_REG			0x04

#define MEM_ADDR2_REG			0x08
#define   ADDR2_STRENGTH(x)		FIELD_PREP(GENMASK(27, 25), (x))
#define   ADDR2_CS(x)			FIELD_PREP(GENMASK(31, 30), (x))

#define CMD_REG				0x0C
#define   CMD_1(x)			FIELD_PREP(GENMASK(7, 0), (x))
#define   CMD_2(x)			FIELD_PREP(GENMASK(15, 8), (x))
#define   CMD_PAGE_SIZE(x)		FIELD_PREP(GENMASK(25, 23), (x))
#define   CMD_DMA_ENABLE		BIT(27)
#define   CMD_NADDRS(x)			FIELD_PREP(GENMASK(30, 28), (x))
#define   CMD_ECC_ENABLE		BIT(31)

#define PROG_REG			0x10
#define   PROG_PGRD			BIT(0)
#define   PROG_ERASE			BIT(2)
#define   PROG_STATUS			BIT(3)
#define   PROG_PGPROG			BIT(4)
#define   PROG_RDID			BIT(6)
#define   PROG_RDPARAM			BIT(7)
#define   PROG_RST			BIT(8)
#define   PROG_GET_FEATURE		BIT(9)
#define   PROG_SET_FEATURE		BIT(10)

#define INTR_STS_EN_REG			0x14
#define INTR_SIG_EN_REG			0x18
#define INTR_STS_REG			0x1C
#define   WRITE_READY			BIT(0)
#define   READ_READY			BIT(1)
#define   XFER_COMPLETE			BIT(2)
#define   DMA_BOUNDARY			BIT(6)
#define   EVENT_MASK			GENMASK(7, 0)

#define READY_STS_REG			0x20

#define DMA_ADDR0_REG			0x50
#define DMA_ADDR1_REG			0x24

#define FLASH_STS_REG			0x28

#define DATA_PORT_REG			0x30

#define ECC_CONF_REG			0x34
#define   ECC_CONF_COL(x)		FIELD_PREP(GENMASK(15, 0), (x))
#define   ECC_CONF_LEN(x)		FIELD_PREP(GENMASK(26, 16), (x))
#define   ECC_CONF_BCH_EN		BIT(27)

#define ECC_ERR_CNT_REG			0x38
#define   GET_PKT_ERR_CNT(x)		FIELD_GET(GENMASK(7, 0), (x))
#define   GET_PAGE_ERR_CNT(x)		FIELD_GET(GENMASK(16, 8), (x))

#define ECC_SP_REG			0x3C
#define   ECC_SP_CMD1(x)		FIELD_PREP(GENMASK(7, 0), (x))
#define   ECC_SP_CMD2(x)		FIELD_PREP(GENMASK(15, 8), (x))
#define   ECC_SP_ADDRS(x)		FIELD_PREP(GENMASK(30, 28), (x))

#define ECC_1ERR_CNT_REG		0x40
#define ECC_2ERR_CNT_REG		0x44

#define DATA_INTERFACE_REG		0x6C
#define   DIFACE_SDR_MODE(x)		FIELD_PREP(GENMASK(2, 0), (x))
#define   DIFACE_DDR_MODE(x)		FIELD_PREP(GENMASK(5, 3), (x))
#define   DIFACE_SDR			0
#define   DIFACE_NVDDR			BIT(9)

#define ANFC_MAX_CS			2
#define ANFC_DFLT_TIMEOUT_US		1000000
#define ANFC_MAX_CHUNK_SIZE		SZ_1M
#define ANFC_MAX_PARAM_SIZE		SZ_4K
#define ANFC_MAX_STEPS			SZ_2K
#define ANFC_MAX_PKT_SIZE		(SZ_2K - 1)
#define ANFC_MAX_ADDR_CYC		5U
#define ANFC_RSVD_ECC_BYTES		21

#define ANFC_XLNX_SDR_DFLT_CORE_CLK	100000000
#define ANFC_XLNX_SDR_HS_CORE_CLK	80000000

/**
 * struct anfc_op - Defines how to execute an operation
 * @pkt_reg: Packet register
 * @addr1_reg: Memory address 1 register
 * @addr2_reg: Memory address 2 register
 * @cmd_reg: Command register
 * @prog_reg: Program register
 * @steps: Number of "packets" to read/write
 * @rdy_timeout_ms: Timeout for waits on Ready/Busy pin
 * @len: Data transfer length
 * @read: Data transfer direction from the controller point of view
 */
struct anfc_op {
	u32 pkt_reg;
	u32 addr1_reg;
	u32 addr2_reg;
	u32 cmd_reg;
	u32 prog_reg;
	int steps;
	unsigned int rdy_timeout_ms;
	unsigned int len;
	bool read;
	u8 *buf;
};

/**
 * struct anand - Defines the NAND chip related information
 * @node:		Used to store NAND chips into a list
 * @chip:		NAND chip information structure
 * @cs:			Chip select line
 * @rb:			Ready-busy line
 * @page_sz:		Register value of the page_sz field to use
 * @clk:		Expected clock frequency to use
 * @timings:		Data interface timing mode to use
 * @ecc_conf:		Hardware ECC configuration value
 * @strength:		Register value of the ECC strength
 * @raddr_cycles:	Row address cycle information
 * @caddr_cycles:	Column address cycle information
 * @ecc_bits:		Exact number of ECC bits per syndrome
 * @ecc_total:		Total number of ECC bytes
 * @errloc:		Array of errors located with soft BCH
 * @hw_ecc:		Buffer to store syndromes computed by hardware
 * @bch:		BCH structure
 */
struct anand {
	struct list_head node;
	struct nand_chip chip;
	unsigned int cs;
	unsigned int rb;
	unsigned int page_sz;
	unsigned long clk;
	u32 timings;
	u32 ecc_conf;
	u32 strength;
	u16 raddr_cycles;
	u16 caddr_cycles;
	unsigned int ecc_bits;
	unsigned int ecc_total;
	unsigned int *errloc;
	u8 *hw_ecc;
	struct bch_control *bch;
};

/**
 * struct arasan_nfc - Defines the Arasan NAND flash controller driver instance
 * @dev:		Pointer to the device structure
 * @base:		Remapped register area
 * @controller_clk:		Pointer to the system clock
 * @bus_clk:		Pointer to the flash clock
 * @controller:		Base controller structure
 * @chips:		List of all NAND chips attached to the controller
 * @assigned_cs:	Bitmask describing already assigned CS lines
 * @cur_clk:		Current clock rate
 */
struct arasan_nfc {
	struct device *dev;
	void __iomem *base;
	struct clk *controller_clk;
	struct clk *bus_clk;
	struct nand_controller controller;
	struct list_head chips;
	unsigned long assigned_cs;
	unsigned int cur_clk;
};

static struct anand *to_anand(struct nand_chip *nand)
{
	return container_of(nand, struct anand, chip);
}

static struct arasan_nfc *to_anfc(struct nand_controller *ctrl)
{
	return container_of(ctrl, struct arasan_nfc, controller);
}

static int anfc_wait_for_event(struct arasan_nfc *nfc, unsigned int event)
{
	u32 val;
	int ret;

	ret = readl_relaxed_poll_timeout(nfc->base + INTR_STS_REG, val,
					 val & event, 0,
					 ANFC_DFLT_TIMEOUT_US);
	if (ret) {
		dev_err(nfc->dev, "Timeout waiting for event 0x%x\n", event);
		return -ETIMEDOUT;
	}

	writel_relaxed(event, nfc->base + INTR_STS_REG);

	return 0;
}

static int anfc_wait_for_rb(struct arasan_nfc *nfc, struct nand_chip *chip,
			    unsigned int timeout_ms)
{
	struct anand *anand = to_anand(chip);
	u32 val;
	int ret;

	/* There is no R/B interrupt, we must poll a register */
	ret = readl_relaxed_poll_timeout(nfc->base + READY_STS_REG, val,
					 val & BIT(anand->rb),
					 1, timeout_ms * 1000);
	if (ret) {
		dev_err(nfc->dev, "Timeout waiting for R/B 0x%x\n",
			readl_relaxed(nfc->base + READY_STS_REG));
		return -ETIMEDOUT;
	}

	return 0;
}

static void anfc_trigger_op(struct arasan_nfc *nfc, struct anfc_op *nfc_op)
{
	writel_relaxed(nfc_op->pkt_reg, nfc->base + PKT_REG);
	writel_relaxed(nfc_op->addr1_reg, nfc->base + MEM_ADDR1_REG);
	writel_relaxed(nfc_op->addr2_reg, nfc->base + MEM_ADDR2_REG);
	writel_relaxed(nfc_op->cmd_reg, nfc->base + CMD_REG);
	writel_relaxed(nfc_op->prog_reg, nfc->base + PROG_REG);
}

static int anfc_pkt_len_config(unsigned int len, unsigned int *steps,
			       unsigned int *pktsize)
{
	unsigned int nb, sz;

	for (nb = 1; nb < ANFC_MAX_STEPS; nb *= 2) {
		sz = len / nb;
		if (sz <= ANFC_MAX_PKT_SIZE)
			break;
	}

	if (sz * nb != len)
		return -ENOTSUPP;

	if (steps)
		*steps = nb;

	if (pktsize)
		*pktsize = sz;

	return 0;
}

static int anfc_select_target(struct nand_chip *chip, int target)
{
	struct anand *anand = to_anand(chip);
	struct arasan_nfc *nfc = to_anfc(chip->controller);
	int ret;

	/* Update the controller timings and the potential ECC configuration */
	writel_relaxed(anand->timings, nfc->base + DATA_INTERFACE_REG);

	/* Update clock frequency */
	if (nfc->cur_clk != anand->clk) {
		clk_disable_unprepare(nfc->bus_clk);
		ret = clk_set_rate(nfc->bus_clk, anand->clk);
		if (ret) {
			dev_err(nfc->dev, "Failed to change clock rate\n");
			return ret;
		}

		ret = clk_prepare_enable(nfc->bus_clk);
		if (ret) {
			dev_err(nfc->dev,
				"Failed to re-enable the bus clock\n");
			return ret;
		}

		nfc->cur_clk = anand->clk;
	}

	return 0;
}

/*
 * When using the embedded hardware ECC engine, the controller is in charge of
 * feeding the engine with, first, the ECC residue present in the data array.
 * A typical read operation is:
 * 1/ Assert the read operation by sending the relevant command/address cycles
 *    but targeting the column of the first ECC bytes in the OOB area instead of
 *    the main data directly.
 * 2/ After having read the relevant number of ECC bytes, the controller uses
 *    the RNDOUT/RNDSTART commands which are set into the "ECC Spare Command
 *    Register" to move the pointer back at the beginning of the main data.
 * 3/ It will read the content of the main area for a given size (pktsize) and
 *    will feed the ECC engine with this buffer again.
 * 4/ The ECC engine derives the ECC bytes for the given data and compare them
 *    with the ones already received. It eventually trigger status flags and
 *    then set the "Buffer Read Ready" flag.
 * 5/ The corrected data is then available for reading from the data port
 *    register.
 *
 * The hardware BCH ECC engine is known to be inconstent in BCH mode and never
 * reports uncorrectable errors. Because of this bug, we have to use the
 * software BCH implementation in the read path.
 */
static int anfc_read_page_hw_ecc(struct nand_chip *chip, u8 *buf,
				 int oob_required, int page)
{
	struct arasan_nfc *nfc = to_anfc(chip->controller);
	struct mtd_info *mtd = nand_to_mtd(chip);
	struct anand *anand = to_anand(chip);
	unsigned int len = mtd->writesize + (oob_required ? mtd->oobsize : 0);
	unsigned int max_bitflips = 0;
	dma_addr_t dma_addr;
	int step, ret;
	struct anfc_op nfc_op = {
		.pkt_reg =
			PKT_SIZE(chip->ecc.size) |
			PKT_STEPS(chip->ecc.steps),
		.addr1_reg =
			(page & 0xFF) << (8 * (anand->caddr_cycles)) |
			(((page >> 8) & 0xFF) << (8 * (1 + anand->caddr_cycles))),
		.addr2_reg =
			((page >> 16) & 0xFF) |
			ADDR2_STRENGTH(anand->strength) |
			ADDR2_CS(anand->cs),
		.cmd_reg =
			CMD_1(NAND_CMD_READ0) |
			CMD_2(NAND_CMD_READSTART) |
			CMD_PAGE_SIZE(anand->page_sz) |
			CMD_DMA_ENABLE |
			CMD_NADDRS(anand->caddr_cycles +
				   anand->raddr_cycles),
		.prog_reg = PROG_PGRD,
	};

	dma_addr = dma_map_single(nfc->dev, (void *)buf, len, DMA_FROM_DEVICE);
	if (dma_mapping_error(nfc->dev, dma_addr)) {
		dev_err(nfc->dev, "Buffer mapping error");
		return -EIO;
	}

	writel_relaxed(lower_32_bits(dma_addr), nfc->base + DMA_ADDR0_REG);
	writel_relaxed(upper_32_bits(dma_addr), nfc->base + DMA_ADDR1_REG);

	anfc_trigger_op(nfc, &nfc_op);

	ret = anfc_wait_for_event(nfc, XFER_COMPLETE);
	dma_unmap_single(nfc->dev, dma_addr, len, DMA_FROM_DEVICE);
	if (ret) {
		dev_err(nfc->dev, "Error reading page %d\n", page);
		return ret;
	}

	/* Store the raw OOB bytes as well */
	ret = nand_change_read_column_op(chip, mtd->writesize, chip->oob_poi,
					 mtd->oobsize, 0);
	if (ret)
		return ret;

	/*
	 * For each step, compute by softare the BCH syndrome over the raw data.
	 * Compare the theoretical amount of errors and compare with the
	 * hardware engine feedback.
	 */
	for (step = 0; step < chip->ecc.steps; step++) {
		u8 *raw_buf = &buf[step * chip->ecc.size];
		unsigned int bit, byte;
		int bf, i;

		/* Extract the syndrome, it is not necessarily aligned */
		memset(anand->hw_ecc, 0, chip->ecc.bytes);
		nand_extract_bits(anand->hw_ecc, 0,
				  &chip->oob_poi[mtd->oobsize - anand->ecc_total],
				  anand->ecc_bits * step, anand->ecc_bits);

		bf = bch_decode(anand->bch, raw_buf, chip->ecc.size,
				anand->hw_ecc, NULL, NULL, anand->errloc);
		if (!bf) {
			continue;
		} else if (bf > 0) {
			for (i = 0; i < bf; i++) {
				/* Only correct the data, not the syndrome */
				if (anand->errloc[i] < (chip->ecc.size * 8)) {
					bit = BIT(anand->errloc[i] & 7);
					byte = anand->errloc[i] >> 3;
					raw_buf[byte] ^= bit;
				}
			}

			mtd->ecc_stats.corrected += bf;
			max_bitflips = max_t(unsigned int, max_bitflips, bf);

			continue;
		}

		bf = nand_check_erased_ecc_chunk(raw_buf, chip->ecc.size,
						 NULL, 0, NULL, 0,
						 chip->ecc.strength);
		if (bf > 0) {
			mtd->ecc_stats.corrected += bf;
			max_bitflips = max_t(unsigned int, max_bitflips, bf);
			memset(raw_buf, 0xFF, chip->ecc.size);
		} else if (bf < 0) {
			mtd->ecc_stats.failed++;
		}
	}

	return 0;
}

static int anfc_sel_read_page_hw_ecc(struct nand_chip *chip, u8 *buf,
				     int oob_required, int page)
{
	int ret;

	ret = anfc_select_target(chip, chip->cur_cs);
	if (ret)
		return ret;

	return anfc_read_page_hw_ecc(chip, buf, oob_required, page);
};

static int anfc_write_page_hw_ecc(struct nand_chip *chip, const u8 *buf,
				  int oob_required, int page)
{
	struct anand *anand = to_anand(chip);
	struct arasan_nfc *nfc = to_anfc(chip->controller);
	struct mtd_info *mtd = nand_to_mtd(chip);
	unsigned int len = mtd->writesize + (oob_required ? mtd->oobsize : 0);
	dma_addr_t dma_addr;
	int ret;
	struct anfc_op nfc_op = {
		.pkt_reg =
			PKT_SIZE(chip->ecc.size) |
			PKT_STEPS(chip->ecc.steps),
		.addr1_reg =
			(page & 0xFF) << (8 * (anand->caddr_cycles)) |
			(((page >> 8) & 0xFF) << (8 * (1 + anand->caddr_cycles))),
		.addr2_reg =
			((page >> 16) & 0xFF) |
			ADDR2_STRENGTH(anand->strength) |
			ADDR2_CS(anand->cs),
		.cmd_reg =
			CMD_1(NAND_CMD_SEQIN) |
			CMD_2(NAND_CMD_PAGEPROG) |
			CMD_PAGE_SIZE(anand->page_sz) |
			CMD_DMA_ENABLE |
			CMD_NADDRS(anand->caddr_cycles +
				   anand->raddr_cycles) |
			CMD_ECC_ENABLE,
		.prog_reg = PROG_PGPROG,
	};

	writel_relaxed(anand->ecc_conf, nfc->base + ECC_CONF_REG);
	writel_relaxed(ECC_SP_CMD1(NAND_CMD_RNDIN) |
		       ECC_SP_ADDRS(anand->caddr_cycles),
		       nfc->base + ECC_SP_REG);

	dma_addr = dma_map_single(nfc->dev, (void *)buf, len, DMA_TO_DEVICE);
	if (dma_mapping_error(nfc->dev, dma_addr)) {
		dev_err(nfc->dev, "Buffer mapping error");
		return -EIO;
	}

	writel_relaxed(lower_32_bits(dma_addr), nfc->base + DMA_ADDR0_REG);
	writel_relaxed(upper_32_bits(dma_addr), nfc->base + DMA_ADDR1_REG);

	anfc_trigger_op(nfc, &nfc_op);
	ret = anfc_wait_for_event(nfc, XFER_COMPLETE);
	dma_unmap_single(nfc->dev, dma_addr, len, DMA_TO_DEVICE);
	if (ret) {
		dev_err(nfc->dev, "Error writing page %d\n", page);
		return ret;
	}

	/* Spare data is not protected */
	if (oob_required)
		ret = nand_write_oob_std(chip, page);

	return ret;
}

static int anfc_sel_write_page_hw_ecc(struct nand_chip *chip, const u8 *buf,
				      int oob_required, int page)
{
	int ret;

	ret = anfc_select_target(chip, chip->cur_cs);
	if (ret)
		return ret;

	return anfc_write_page_hw_ecc(chip, buf, oob_required, page);
};

/* NAND framework ->exec_op() hooks and related helpers */
static int anfc_parse_instructions(struct nand_chip *chip,
				   const struct nand_subop *subop,
				   struct anfc_op *nfc_op)
{
	struct anand *anand = to_anand(chip);
	const struct nand_op_instr *instr = NULL;
	bool first_cmd = true;
	unsigned int op_id;
	int ret, i;

	memset(nfc_op, 0, sizeof(*nfc_op));
	nfc_op->addr2_reg = ADDR2_CS(anand->cs);
	nfc_op->cmd_reg = CMD_PAGE_SIZE(anand->page_sz);

	for (op_id = 0; op_id < subop->ninstrs; op_id++) {
		unsigned int offset, naddrs, pktsize;
		const u8 *addrs;
		u8 *buf;

		instr = &subop->instrs[op_id];

		switch (instr->type) {
		case NAND_OP_CMD_INSTR:
			if (first_cmd)
				nfc_op->cmd_reg |= CMD_1(instr->ctx.cmd.opcode);
			else
				nfc_op->cmd_reg |= CMD_2(instr->ctx.cmd.opcode);

			first_cmd = false;
			break;

		case NAND_OP_ADDR_INSTR:
			offset = nand_subop_get_addr_start_off(subop, op_id);
			naddrs = nand_subop_get_num_addr_cyc(subop, op_id);
			addrs = &instr->ctx.addr.addrs[offset];
			nfc_op->cmd_reg |= CMD_NADDRS(naddrs);

			for (i = 0; i < min(ANFC_MAX_ADDR_CYC, naddrs); i++) {
				if (i < 4)
					nfc_op->addr1_reg |= (u32)addrs[i] << i * 8;
				else
					nfc_op->addr2_reg |= addrs[i];
			}

			break;
		case NAND_OP_DATA_IN_INSTR:
			nfc_op->read = true;
			fallthrough;
		case NAND_OP_DATA_OUT_INSTR:
			offset = nand_subop_get_data_start_off(subop, op_id);
			buf = instr->ctx.data.buf.in;
			nfc_op->buf = &buf[offset];
			nfc_op->len = nand_subop_get_data_len(subop, op_id);
			ret = anfc_pkt_len_config(nfc_op->len, &nfc_op->steps,
						  &pktsize);
			if (ret)
				return ret;

			/*
			 * Number of DATA cycles must be aligned on 4, this
			 * means the controller might read/write more than
			 * requested. This is harmless most of the time as extra
			 * DATA are discarded in the write path and read pointer
			 * adjusted in the read path.
			 *
			 * FIXME: The core should mark operations where
			 * reading/writing more is allowed so the exec_op()
			 * implementation can take the right decision when the
			 * alignment constraint is not met: adjust the number of
			 * DATA cycles when it's allowed, reject the operation
			 * otherwise.
			 */
			nfc_op->pkt_reg |= PKT_SIZE(round_up(pktsize, 4)) |
					   PKT_STEPS(nfc_op->steps);
			break;
		case NAND_OP_WAITRDY_INSTR:
			nfc_op->rdy_timeout_ms = instr->ctx.waitrdy.timeout_ms;
			break;
		}
	}

	return 0;
}

static int anfc_rw_pio_op(struct arasan_nfc *nfc, struct anfc_op *nfc_op)
{
	unsigned int dwords = (nfc_op->len / 4) / nfc_op->steps;
	unsigned int last_len = nfc_op->len % 4;
	unsigned int offset, dir;
	u8 *buf = nfc_op->buf;
	int ret, i;

	for (i = 0; i < nfc_op->steps; i++) {
		dir = nfc_op->read ? READ_READY : WRITE_READY;
		ret = anfc_wait_for_event(nfc, dir);
		if (ret) {
			dev_err(nfc->dev, "PIO %s ready signal not received\n",
				nfc_op->read ? "Read" : "Write");
			return ret;
		}

		offset = i * (dwords * 4);
		if (nfc_op->read)
			ioread32_rep(nfc->base + DATA_PORT_REG, &buf[offset],
				     dwords);
		else
			iowrite32_rep(nfc->base + DATA_PORT_REG, &buf[offset],
				      dwords);
	}

	if (last_len) {
		u32 remainder;

		offset = nfc_op->len - last_len;

		if (nfc_op->read) {
			remainder = readl_relaxed(nfc->base + DATA_PORT_REG);
			memcpy(&buf[offset], &remainder, last_len);
		} else {
			memcpy(&remainder, &buf[offset], last_len);
			writel_relaxed(remainder, nfc->base + DATA_PORT_REG);
		}
	}

	return anfc_wait_for_event(nfc, XFER_COMPLETE);
}

static int anfc_misc_data_type_exec(struct nand_chip *chip,
				    const struct nand_subop *subop,
				    u32 prog_reg)
{
	struct arasan_nfc *nfc = to_anfc(chip->controller);
	struct anfc_op nfc_op = {};
	int ret;

	ret = anfc_parse_instructions(chip, subop, &nfc_op);
	if (ret)
		return ret;

	nfc_op.prog_reg = prog_reg;
	anfc_trigger_op(nfc, &nfc_op);

	if (nfc_op.rdy_timeout_ms) {
		ret = anfc_wait_for_rb(nfc, chip, nfc_op.rdy_timeout_ms);
		if (ret)
			return ret;
	}

	return anfc_rw_pio_op(nfc, &nfc_op);
}

static int anfc_param_read_type_exec(struct nand_chip *chip,
				     const struct nand_subop *subop)
{
	return anfc_misc_data_type_exec(chip, subop, PROG_RDPARAM);
}

static int anfc_data_read_type_exec(struct nand_chip *chip,
				    const struct nand_subop *subop)
{
	return anfc_misc_data_type_exec(chip, subop, PROG_PGRD);
}

static int anfc_param_write_type_exec(struct nand_chip *chip,
				      const struct nand_subop *subop)
{
	return anfc_misc_data_type_exec(chip, subop, PROG_SET_FEATURE);
}

static int anfc_data_write_type_exec(struct nand_chip *chip,
				     const struct nand_subop *subop)
{
	return anfc_misc_data_type_exec(chip, subop, PROG_PGPROG);
}

static int anfc_misc_zerolen_type_exec(struct nand_chip *chip,
				       const struct nand_subop *subop,
				       u32 prog_reg)
{
	struct arasan_nfc *nfc = to_anfc(chip->controller);
	struct anfc_op nfc_op = {};
	int ret;

	ret = anfc_parse_instructions(chip, subop, &nfc_op);
	if (ret)
		return ret;

	nfc_op.prog_reg = prog_reg;
	anfc_trigger_op(nfc, &nfc_op);

	ret = anfc_wait_for_event(nfc, XFER_COMPLETE);
	if (ret)
		return ret;

	if (nfc_op.rdy_timeout_ms)
		ret = anfc_wait_for_rb(nfc, chip, nfc_op.rdy_timeout_ms);

	return ret;
}

static int anfc_status_type_exec(struct nand_chip *chip,
				 const struct nand_subop *subop)
{
	struct arasan_nfc *nfc = to_anfc(chip->controller);
	u32 tmp;
	int ret;

	/* See anfc_check_op() for details about this constraint */
	if (subop->instrs[0].ctx.cmd.opcode != NAND_CMD_STATUS)
		return -ENOTSUPP;

	ret = anfc_misc_zerolen_type_exec(chip, subop, PROG_STATUS);
	if (ret)
		return ret;

	tmp = readl_relaxed(nfc->base + FLASH_STS_REG);
	memcpy(subop->instrs[1].ctx.data.buf.in, &tmp, 1);

	return 0;
}

static int anfc_reset_type_exec(struct nand_chip *chip,
				const struct nand_subop *subop)
{
	return anfc_misc_zerolen_type_exec(chip, subop, PROG_RST);
}

static int anfc_erase_type_exec(struct nand_chip *chip,
				const struct nand_subop *subop)
{
	return anfc_misc_zerolen_type_exec(chip, subop, PROG_ERASE);
}

static int anfc_wait_type_exec(struct nand_chip *chip,
			       const struct nand_subop *subop)
{
	struct arasan_nfc *nfc = to_anfc(chip->controller);
	struct anfc_op nfc_op = {};
	int ret;

	ret = anfc_parse_instructions(chip, subop, &nfc_op);
	if (ret)
		return ret;

	return anfc_wait_for_rb(nfc, chip, nfc_op.rdy_timeout_ms);
}

static const struct nand_op_parser anfc_op_parser = NAND_OP_PARSER(
	NAND_OP_PARSER_PATTERN(
		anfc_param_read_type_exec,
		NAND_OP_PARSER_PAT_CMD_ELEM(false),
		NAND_OP_PARSER_PAT_ADDR_ELEM(false, ANFC_MAX_ADDR_CYC),
		NAND_OP_PARSER_PAT_WAITRDY_ELEM(true),
		NAND_OP_PARSER_PAT_DATA_IN_ELEM(false, ANFC_MAX_CHUNK_SIZE)),
	NAND_OP_PARSER_PATTERN(
		anfc_param_write_type_exec,
		NAND_OP_PARSER_PAT_CMD_ELEM(false),
		NAND_OP_PARSER_PAT_ADDR_ELEM(false, ANFC_MAX_ADDR_CYC),
		NAND_OP_PARSER_PAT_DATA_OUT_ELEM(false, ANFC_MAX_PARAM_SIZE)),
	NAND_OP_PARSER_PATTERN(
		anfc_data_read_type_exec,
		NAND_OP_PARSER_PAT_CMD_ELEM(false),
		NAND_OP_PARSER_PAT_ADDR_ELEM(false, ANFC_MAX_ADDR_CYC),
		NAND_OP_PARSER_PAT_CMD_ELEM(false),
		NAND_OP_PARSER_PAT_WAITRDY_ELEM(true),
		NAND_OP_PARSER_PAT_DATA_IN_ELEM(true, ANFC_MAX_CHUNK_SIZE)),
	NAND_OP_PARSER_PATTERN(
		anfc_data_write_type_exec,
		NAND_OP_PARSER_PAT_CMD_ELEM(false),
		NAND_OP_PARSER_PAT_ADDR_ELEM(false, ANFC_MAX_ADDR_CYC),
		NAND_OP_PARSER_PAT_DATA_OUT_ELEM(false, ANFC_MAX_CHUNK_SIZE),
		NAND_OP_PARSER_PAT_CMD_ELEM(false)),
	NAND_OP_PARSER_PATTERN(
		anfc_reset_type_exec,
		NAND_OP_PARSER_PAT_CMD_ELEM(false),
		NAND_OP_PARSER_PAT_WAITRDY_ELEM(false)),
	NAND_OP_PARSER_PATTERN(
		anfc_erase_type_exec,
		NAND_OP_PARSER_PAT_CMD_ELEM(false),
		NAND_OP_PARSER_PAT_ADDR_ELEM(false, ANFC_MAX_ADDR_CYC),
		NAND_OP_PARSER_PAT_CMD_ELEM(false),
		NAND_OP_PARSER_PAT_WAITRDY_ELEM(false)),
	NAND_OP_PARSER_PATTERN(
		anfc_status_type_exec,
		NAND_OP_PARSER_PAT_CMD_ELEM(false),
		NAND_OP_PARSER_PAT_DATA_IN_ELEM(false, ANFC_MAX_CHUNK_SIZE)),
	NAND_OP_PARSER_PATTERN(
		anfc_wait_type_exec,
		NAND_OP_PARSER_PAT_WAITRDY_ELEM(false)),
	);

static int anfc_check_op(struct nand_chip *chip,
			 const struct nand_operation *op)
{
	const struct nand_op_instr *instr;
	int op_id;

	/*
	 * The controller abstracts all the NAND operations and do not support
	 * data only operations.
	 *
	 * TODO: The nand_op_parser framework should be extended to
	 * support custom checks on DATA instructions.
	 */
	for (op_id = 0; op_id < op->ninstrs; op_id++) {
		instr = &op->instrs[op_id];

		switch (instr->type) {
		case NAND_OP_ADDR_INSTR:
			if (instr->ctx.addr.naddrs > ANFC_MAX_ADDR_CYC)
				return -ENOTSUPP;

			break;
		case NAND_OP_DATA_IN_INSTR:
		case NAND_OP_DATA_OUT_INSTR:
			if (instr->ctx.data.len > ANFC_MAX_CHUNK_SIZE)
				return -ENOTSUPP;

			if (anfc_pkt_len_config(instr->ctx.data.len, 0, 0))
				return -ENOTSUPP;

			break;
		default:
			break;
		}
	}

	/*
	 * The controller does not allow to proceed with a CMD+DATA_IN cycle
	 * manually on the bus by reading data from the data register. Instead,
	 * the controller abstract a status read operation with its own status
	 * register after ordering a read status operation. Hence, we cannot
	 * support any CMD+DATA_IN operation other than a READ STATUS.
	 *
	 * TODO: The nand_op_parser() framework should be extended to describe
	 * fixed patterns instead of open-coding this check here.
	 */
	if (op->ninstrs == 2 &&
	    op->instrs[0].type == NAND_OP_CMD_INSTR &&
	    op->instrs[0].ctx.cmd.opcode != NAND_CMD_STATUS &&
	    op->instrs[1].type == NAND_OP_DATA_IN_INSTR)
		return -ENOTSUPP;

	return nand_op_parser_exec_op(chip, &anfc_op_parser, op, true);
}

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

	if (check_only)
		return anfc_check_op(chip, op);

	ret = anfc_select_target(chip, op->cs);
	if (ret)
		return ret;

	return nand_op_parser_exec_op(chip, &anfc_op_parser, op, check_only);
}

static int anfc_setup_interface(struct nand_chip *chip, int target,
				const struct nand_interface_config *conf)
{
	struct anand *anand = to_anand(chip);
	struct arasan_nfc *nfc = to_anfc(chip->controller);
	struct device_node *np = nfc->dev->of_node;
	const struct nand_sdr_timings *sdr;
	const struct nand_nvddr_timings *nvddr;

	if (nand_interface_is_nvddr(conf)) {
		nvddr = nand_get_nvddr_timings(conf);
		if (IS_ERR(nvddr))
			return PTR_ERR(nvddr);

		/*
		 * The controller only supports data payload requests which are
		 * a multiple of 4. In practice, most data accesses are 4-byte
		 * aligned and this is not an issue. However, rounding up will
		 * simply be refused by the controller if we reached the end of
		 * the device *and* we are using the NV-DDR interface(!). In
		 * this situation, unaligned data requests ending at the device
		 * boundary will confuse the controller and cannot be performed.
		 *
		 * This is something that happens in nand_read_subpage() when
		 * selecting software ECC support and must be avoided.
		 */
		if (chip->ecc.engine_type == NAND_ECC_ENGINE_TYPE_SOFT)
			return -ENOTSUPP;
	} else {
		sdr = nand_get_sdr_timings(conf);
		if (IS_ERR(sdr))
			return PTR_ERR(sdr);
	}

	if (target < 0)
		return 0;

	if (nand_interface_is_sdr(conf))
		anand->timings = DIFACE_SDR |
				 DIFACE_SDR_MODE(conf->timings.mode);
	else
		anand->timings = DIFACE_NVDDR |
				 DIFACE_DDR_MODE(conf->timings.mode);

	if (nand_interface_is_sdr(conf)) {
		anand->clk = ANFC_XLNX_SDR_DFLT_CORE_CLK;
	} else {
		/* ONFI timings are defined in picoseconds */
		anand->clk = div_u64((u64)NSEC_PER_SEC * 1000,
				     conf->timings.nvddr.tCK_min);
	}

	/*
	 * Due to a hardware bug in the ZynqMP SoC, SDR timing modes 0-1 work
	 * with f > 90MHz (default clock is 100MHz) but signals are unstable
	 * with higher modes. Hence we decrease a little bit the clock rate to
	 * 80MHz when using SDR modes 2-5 with this SoC.
	 */
	if (of_device_is_compatible(np, "xlnx,zynqmp-nand-controller") &&
	    nand_interface_is_sdr(conf) && conf->timings.mode >= 2)
		anand->clk = ANFC_XLNX_SDR_HS_CORE_CLK;

	return 0;
}

static int anfc_calc_hw_ecc_bytes(int step_size, int strength)
{
	unsigned int bch_gf_mag, ecc_bits;

	switch (step_size) {
	case SZ_512:
		bch_gf_mag = 13;
		break;
	case SZ_1K:
		bch_gf_mag = 14;
		break;
	default:
		return -EINVAL;
	}

	ecc_bits = bch_gf_mag * strength;

	return DIV_ROUND_UP(ecc_bits, 8);
}

static const int anfc_hw_ecc_512_strengths[] = {4, 8, 12};

static const int anfc_hw_ecc_1024_strengths[] = {24};

static const struct nand_ecc_step_info anfc_hw_ecc_step_infos[] = {
	{
		.stepsize = SZ_512,
		.strengths = anfc_hw_ecc_512_strengths,
		.nstrengths = ARRAY_SIZE(anfc_hw_ecc_512_strengths),
	},
	{
		.stepsize = SZ_1K,
		.strengths = anfc_hw_ecc_1024_strengths,
		.nstrengths = ARRAY_SIZE(anfc_hw_ecc_1024_strengths),
	},
};

static const struct nand_ecc_caps anfc_hw_ecc_caps = {
	.stepinfos = anfc_hw_ecc_step_infos,
	.nstepinfos = ARRAY_SIZE(anfc_hw_ecc_step_infos),
	.calc_ecc_bytes = anfc_calc_hw_ecc_bytes,
};

static int anfc_init_hw_ecc_controller(struct arasan_nfc *nfc,
				       struct nand_chip *chip)
{
	struct anand *anand = to_anand(chip);
	struct mtd_info *mtd = nand_to_mtd(chip);
	struct nand_ecc_ctrl *ecc = &chip->ecc;
	unsigned int bch_prim_poly = 0, bch_gf_mag = 0, ecc_offset;
	int ret;

	switch (mtd->writesize) {
	case SZ_512:
	case SZ_2K:
	case SZ_4K:
	case SZ_8K:
	case SZ_16K:
		break;
	default:
		dev_err(nfc->dev, "Unsupported page size %d\n", mtd->writesize);
		return -EINVAL;
	}

	ret = nand_ecc_choose_conf(chip, &anfc_hw_ecc_caps, mtd->oobsize);
	if (ret)
		return ret;

	switch (ecc->strength) {
	case 12:
		anand->strength = 0x1;
		break;
	case 8:
		anand->strength = 0x2;
		break;
	case 4:
		anand->strength = 0x3;
		break;
	case 24:
		anand->strength = 0x4;
		break;
	default:
		dev_err(nfc->dev, "Unsupported strength %d\n", ecc->strength);
		return -EINVAL;
	}

	switch (ecc->size) {
	case SZ_512:
		bch_gf_mag = 13;
		bch_prim_poly = 0x201b;
		break;
	case SZ_1K:
		bch_gf_mag = 14;
		bch_prim_poly = 0x4443;
		break;
	default:
		dev_err(nfc->dev, "Unsupported step size %d\n", ecc->strength);
		return -EINVAL;
	}

	mtd_set_ooblayout(mtd, nand_get_large_page_ooblayout());

	ecc->steps = mtd->writesize / ecc->size;
	ecc->algo = NAND_ECC_ALGO_BCH;
	anand->ecc_bits = bch_gf_mag * ecc->strength;
	ecc->bytes = DIV_ROUND_UP(anand->ecc_bits, 8);
	anand->ecc_total = DIV_ROUND_UP(anand->ecc_bits * ecc->steps, 8);
	ecc_offset = mtd->writesize + mtd->oobsize - anand->ecc_total;
	anand->ecc_conf = ECC_CONF_COL(ecc_offset) |
			  ECC_CONF_LEN(anand->ecc_total) |
			  ECC_CONF_BCH_EN;

	anand->errloc = devm_kmalloc_array(nfc->dev, ecc->strength,
					   sizeof(*anand->errloc), GFP_KERNEL);
	if (!anand->errloc)
		return -ENOMEM;

	anand->hw_ecc = devm_kmalloc(nfc->dev, ecc->bytes, GFP_KERNEL);
	if (!anand->hw_ecc)
		return -ENOMEM;

	/* Enforce bit swapping to fit the hardware */
	anand->bch = bch_init(bch_gf_mag, ecc->strength, bch_prim_poly, true);
	if (!anand->bch)
		return -EINVAL;

	ecc->read_page = anfc_sel_read_page_hw_ecc;
	ecc->write_page = anfc_sel_write_page_hw_ecc;

	return 0;
}

static int anfc_attach_chip(struct nand_chip *chip)
{
	struct anand *anand = to_anand(chip);
	struct arasan_nfc *nfc = to_anfc(chip->controller);
	struct mtd_info *mtd = nand_to_mtd(chip);
	int ret = 0;

	if (mtd->writesize <= SZ_512)
		anand->caddr_cycles = 1;
	else
		anand->caddr_cycles = 2;

	if (chip->options & NAND_ROW_ADDR_3)
		anand->raddr_cycles = 3;
	else
		anand->raddr_cycles = 2;

	switch (mtd->writesize) {
	case 512:
		anand->page_sz = 0;
		break;
	case 1024:
		anand->page_sz = 5;
		break;
	case 2048:
		anand->page_sz = 1;
		break;
	case 4096:
		anand->page_sz = 2;
		break;
	case 8192:
		anand->page_sz = 3;
		break;
	case 16384:
		anand->page_sz = 4;
		break;
	default:
		return -EINVAL;
	}

	/* These hooks are valid for all ECC providers */
	chip->ecc.read_page_raw = nand_monolithic_read_page_raw;
	chip->ecc.write_page_raw = nand_monolithic_write_page_raw;

	switch (chip->ecc.engine_type) {
	case NAND_ECC_ENGINE_TYPE_NONE:
	case NAND_ECC_ENGINE_TYPE_SOFT:
	case NAND_ECC_ENGINE_TYPE_ON_DIE:
		break;
	case NAND_ECC_ENGINE_TYPE_ON_HOST:
		ret = anfc_init_hw_ecc_controller(nfc, chip);
		break;
	default:
		dev_err(nfc->dev, "Unsupported ECC mode: %d\n",
			chip->ecc.engine_type);
		return -EINVAL;
	}

	return ret;
}

static void anfc_detach_chip(struct nand_chip *chip)
{
	struct anand *anand = to_anand(chip);

	if (anand->bch)
		bch_free(anand->bch);
}

static const struct nand_controller_ops anfc_ops = {
	.exec_op = anfc_exec_op,
	.setup_interface = anfc_setup_interface,
	.attach_chip = anfc_attach_chip,
	.detach_chip = anfc_detach_chip,
};

static int anfc_chip_init(struct arasan_nfc *nfc, struct device_node *np)
{
	struct anand *anand;
	struct nand_chip *chip;
	struct mtd_info *mtd;
	int cs, rb, ret;

	anand = devm_kzalloc(nfc->dev, sizeof(*anand), GFP_KERNEL);
	if (!anand)
		return -ENOMEM;

	/* We do not support multiple CS per chip yet */
	if (of_property_count_elems_of_size(np, "reg", sizeof(u32)) != 1) {
		dev_err(nfc->dev, "Invalid reg property\n");
		return -EINVAL;
	}

	ret = of_property_read_u32(np, "reg", &cs);
	if (ret)
		return ret;

	ret = of_property_read_u32(np, "nand-rb", &rb);
	if (ret)
		return ret;

	if (cs >= ANFC_MAX_CS || rb >= ANFC_MAX_CS) {
		dev_err(nfc->dev, "Wrong CS %d or RB %d\n", cs, rb);
		return -EINVAL;
	}

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

	anand->cs = cs;
	anand->rb = rb;

	chip = &anand->chip;
	mtd = nand_to_mtd(chip);
	mtd->dev.parent = nfc->dev;
	chip->controller = &nfc->controller;
	chip->options = NAND_BUSWIDTH_AUTO | NAND_NO_SUBPAGE_WRITE |
			NAND_USES_DMA;

	nand_set_flash_node(chip, np);
	if (!mtd->name) {
		dev_err(nfc->dev, "NAND label property is mandatory\n");
		return -EINVAL;
	}

	ret = nand_scan(chip, 1);
	if (ret) {
		dev_err(nfc->dev, "Scan operation failed\n");
		return ret;
	}

	ret = mtd_device_register(mtd, NULL, 0);
	if (ret) {
		nand_cleanup(chip);
		return ret;
	}

	list_add_tail(&anand->node, &nfc->chips);

	return 0;
}

static void anfc_chips_cleanup(struct arasan_nfc *nfc)
{
	struct anand *anand, *tmp;
	struct nand_chip *chip;
	int ret;

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

static int anfc_chips_init(struct arasan_nfc *nfc)
{
	struct device_node *np = nfc->dev->of_node, *nand_np;
	int nchips = of_get_child_count(np);
	int ret;

	if (!nchips || nchips > ANFC_MAX_CS) {
		dev_err(nfc->dev, "Incorrect number of NAND chips (%d)\n",
			nchips);
		return -EINVAL;
	}

	for_each_child_of_node(np, nand_np) {
		ret = anfc_chip_init(nfc, nand_np);
		if (ret) {
			of_node_put(nand_np);
			anfc_chips_cleanup(nfc);
			break;
		}
	}

	return ret;
}

static void anfc_reset(struct arasan_nfc *nfc)
{
	/* Disable interrupt signals */
	writel_relaxed(0, nfc->base + INTR_SIG_EN_REG);

	/* Enable interrupt status */
	writel_relaxed(EVENT_MASK, nfc->base + INTR_STS_EN_REG);
}

static int anfc_probe(struct platform_device *pdev)
{
	struct arasan_nfc *nfc;
	int ret;

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

	nfc->dev = &pdev->dev;
	nand_controller_init(&nfc->controller);
	nfc->controller.ops = &anfc_ops;
	INIT_LIST_HEAD(&nfc->chips);

	nfc->base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(nfc->base))
		return PTR_ERR(nfc->base);

	anfc_reset(nfc);

	nfc->controller_clk = devm_clk_get(&pdev->dev, "controller");
	if (IS_ERR(nfc->controller_clk))
		return PTR_ERR(nfc->controller_clk);

	nfc->bus_clk = devm_clk_get(&pdev->dev, "bus");
	if (IS_ERR(nfc->bus_clk))
		return PTR_ERR(nfc->bus_clk);

	ret = clk_prepare_enable(nfc->controller_clk);
	if (ret)
		return ret;

	ret = clk_prepare_enable(nfc->bus_clk);
	if (ret)
		goto disable_controller_clk;

	ret = anfc_chips_init(nfc);
	if (ret)
		goto disable_bus_clk;

	platform_set_drvdata(pdev, nfc);

	return 0;

disable_bus_clk:
	clk_disable_unprepare(nfc->bus_clk);

disable_controller_clk:
	clk_disable_unprepare(nfc->controller_clk);

	return ret;
}

static int anfc_remove(struct platform_device *pdev)
{
	struct arasan_nfc *nfc = platform_get_drvdata(pdev);

	anfc_chips_cleanup(nfc);

	clk_disable_unprepare(nfc->bus_clk);
	clk_disable_unprepare(nfc->controller_clk);

	return 0;
}

static const struct of_device_id anfc_ids[] = {
	{
		.compatible = "xlnx,zynqmp-nand-controller",
	},
	{
		.compatible = "arasan,nfc-v3p10",
	},
	{}
};
MODULE_DEVICE_TABLE(of, anfc_ids);

static struct platform_driver anfc_driver = {
	.driver = {
		.name = "arasan-nand-controller",
		.of_match_table = anfc_ids,
	},
	.probe = anfc_probe,
	.remove = anfc_remove,
};
module_platform_driver(anfc_driver);

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Punnaiah Choudary Kalluri <punnaia@xilinx.com>");
MODULE_AUTHOR("Naga Sureshkumar Relli <nagasure@xilinx.com>");
MODULE_AUTHOR("Miquel Raynal <miquel.raynal@bootlin.com>");
MODULE_DESCRIPTION("Arasan NAND Flash Controller Driver");