RE: [LINUX PATCH v13] rawnand: pl353: Add basic driver for arm pl353 smc nand interface

[Naga Sureshkumar Relli <nagasure@xilinx.com>]

Hi Miquel,

Thanks for the review.
I will update the driver to remove legacy hooks.
Apart from that, Do you have any other comments on this driver?
If any, I will fix those.

Thanks,
Naga Sureshkumar Relli

> -----Original Message-----
> From: Naga Sureshkumar Relli <nagasure@xilinx.com>
> Sent: Monday, March 4, 2019 5:17 PM
> To: Miquel Raynal <miquel.raynal@bootlin.com>
> Cc: bbrezillon@kernel.org; richard@nod.at; dwmw2@infradead.org;
> computersforpeace@gmail.com; marek.vasut@gmail.com; linux-mtd@lists.infradead.org; linux-
> kernel@vger.kernel.org; Michal Simek <michals@xilinx.com>;
> nagasureshkumarrelli@gmail.com
> Subject: RE: [LINUX PATCH v13] rawnand: pl353: Add basic driver for arm pl353 smc nand
> interface
> 
> Hi Miquel,
> 
> > -----Original Message-----
> > From: Miquel Raynal <miquel.raynal@bootlin.com>
> > Sent: Monday, March 4, 2019 3:13 PM
> > To: Naga Sureshkumar Relli <nagasure@xilinx.com>
> > Cc: bbrezillon@kernel.org; richard@nod.at; dwmw2@infradead.org;
> > computersforpeace@gmail.com; marek.vasut@gmail.com; linux-mtd@lists.infradead.org;
> linux-
> > kernel@vger.kernel.org; Michal Simek <michals@xilinx.com>;
> > nagasureshkumarrelli@gmail.com
> > Subject: Re: [LINUX PATCH v13] rawnand: pl353: Add basic driver for arm pl353 smc
> nand
> > interface
> >
> > Hi Naga,
> >
> > Naga Sureshkumar Relli <naga.sureshkumar.relli@xilinx.com> wrote on
> > Sat, 9 Feb 2019 12:07:27 +0530:
> >
> > > Add driver for arm pl353 static memory controller nand interface with
> > > HW ECC support. This controller is used in Xilinx Zynq SoC for
> > > interfacing the NAND flash memory.
> > >
> > > Signed-off-by: Naga Sureshkumar Relli <naga.sureshkumar.relli@xilinx.com>
> > > ---
> > > xilinx zynq TRM link:
> > > https://www.xilinx.com/support/documentation/user_guides/ug585-Zynq-7000-
> TRM.pdf
> > >
> > > ARM pl353 smc TRM link:
> > >
> >
> http://infocenter.arm.com/help/topic/com.arm.doc.ddi0380g/DDI0380G_smc_pl350_series_
> > r2p1_trm.pdf
> > >
> > > Tested Micron MT29F2G08ABAEAWP (On-die capable) and AMD/Spansion
> > S34ML01G1.
> > >
> > > SMC memory controller driver is at drivers/memory/pl353-smc.c
> > >
> > > Changes in v13:
> > >  - Rebased the driver to mtd/next
> > > Changes in v12:
> > >  - Rebased the driver on top of v4.19 nand tree
> > >  - Removed nand_scan_ident() and nand_scan_tail(), and added nand_controller_ops
> > >    with ->attach_chip() and used nand_scan() instead.
> > >  - Renamed pl353_nand_info structure to pl353_nand_controller
> > >  - Renamed nand_base and nandaddr in pl353_nand_controller to 'regs' and 'buf_addr'
> > >  - Added new API pl353_wait_for_ecc_done() to wait for ecc done and call it from
> > >    pl353_nand_write_page_hwecc() and pl353_nand_read_page_hwecc()
> > >  - Defined new macro for max ECC blocks
> > >  - Added return value check for ecc.calculate()
> > >  - Renamed pl353_nand_cmd_function() to pl353_nand_exec_op_cmd()
> > >  - Added x16 bus-width support
> > >  - The dependent driver pl353-smc is already reviewed and hence dropped the
> > >    smc driver
> > > Changes in v11:
> > >  - Removed Documentation patch and added the required info in driver as
> > >    per Boris comments.
> > >  - Removed unwanted variables from pl353_nand_info as per Miquel comments
> > >  - Removed IO_ADDR_R/W.
> > >  - Replaced onhot() with hweight32()
> > >  - Defined macros for static values in function pl353_nand_correct_data()
> > >  - Removed all unnecessary delays
> > >  - Used nand_wait_ready() where ever is required
> > >  - Modifed the pl353_setup_data_interface() logic as per Miquel comments.
> > >  - Taken array instead of 7 values in pl353_setup_data_interface() and pass
> > >    it to smc driver.
> > >  - Added check to collect the return value of mtd_device_register().
> > > Changes in 10:
> > >  - Typos correction like nand to NAND and soc to SOC etc..
> > >  - Defined macros for the values in pl353_nand_calculate_hwecc()
> > >  - Modifed ecc_status from int to char in pl353_nand_calculate_hwecc()
> > >  - Changed the return type form int to bool to the function
> > >    onehot()
> > >  - Removed udelay(1000) in pl353_cmd_function, as it is not required
> > >  - Dropped ecc->hwctl = NULL in pl353_ecc_init()
> > >  - Added an error message in pl353_ecc_init(), when there is no matching
> > >    oobsize
> > >  - Changed the variable from xnand to xnfc
> > >  - Added logic to get mtd->name from DT, if it is specified in DT
> > > Changes in v9:
> > >  - Addressed the below comments given by Miquel
> > >  - instead of using pl353_nand_write32, use directly writel_relaxed
> > >  - Fixed check patch warnings
> > >  - Renamed write_buf/read_buf to write_data_op/read_data_op
> > >  - use BIT macro instead of 1 << nr
> > >  - Use NAND_ROW_ADDR_3 flag
> > >  - Use nand_wait_ready()
> > >  - Removed swecc functions
> > >  - Use address cycles as per size, instead of reading it from Parameter page
> > >  - Instead of writing too many patterns, use optional property
> > > Changes in v8:
> > >  - Added exec_op() implementation
> > >  - Fixed the below v7 review comments
> > >  - removed mtd_info from pl353_nand_info struct
> > >  - Corrected ecc layout offsets
> > >  - Added on-die ecc support
> > > Changes in v7:
> > >  - Currently not implemented the memclk rate adjustments. I will
> > >    look into this later and once the basic driver is accepted.
> > >  - Fixed GPL licence ident
> > > Changes in v6:
> > >  - Fixed the checkpatch.pl reported warnings
> > >  - Using the address cycles information from the onfi param page
> > >    earlier it is hardcoded to 5 in driver
> > > Changes in v5:
> > >  - Configure the nand timing parameters as per the onfi spec Changes in v4:
> > >  - Updated the driver to sync with pl353_smc driver APIs
> > > Changes in v3:
> > >  - implemented the proper error codes
> > >  - further breakdown this patch to multiple sets
> > >  - added the controller and driver details to Documentation section
> > >  - updated the licenece to GPLv2
> > >  - reorganized the pl353_nand_ecc_init function
> > > Changes in v2:
> > >  - use "depends on" rather than "select" option in kconfig
> > >  - remove unused variable parts
> > > ---
> > >  drivers/mtd/nand/raw/Kconfig      |    8 +
> > >  drivers/mtd/nand/raw/Makefile     |    1 +
> > >  drivers/mtd/nand/raw/pl353_nand.c | 1380
> > +++++++++++++++++++++++++++++++++++++
> > >  3 files changed, 1389 insertions(+)
> > >  create mode 100644 drivers/mtd/nand/raw/pl353_nand.c
> > >
> > > diff --git a/drivers/mtd/nand/raw/Kconfig b/drivers/mtd/nand/raw/Kconfig
> > > index 1a55d3e..bc6c0a0 100644
> > > --- a/drivers/mtd/nand/raw/Kconfig
> > > +++ b/drivers/mtd/nand/raw/Kconfig
> > > @@ -541,4 +541,12 @@ config MTD_NAND_TEGRA
> > >  	  is supported. Extra OOB bytes when using HW ECC are currently
> > >  	  not supported.
> > >
> > > +config MTD_NAND_PL353
> > > +	tristate "ARM Pl353 NAND flash driver"
> > > +	depends on MTD_NAND && ARM
> > > +	depends on PL353_SMC
> > > +	help
> > > +	  Enables support for PrimeCell Static Memory Controller PL353.
> > > +
> > > +
> > >  endif # MTD_NAND
> > > diff --git a/drivers/mtd/nand/raw/Makefile b/drivers/mtd/nand/raw/Makefile
> > > index 57159b3..9d3c48d 100644
> > > --- a/drivers/mtd/nand/raw/Makefile
> > > +++ b/drivers/mtd/nand/raw/Makefile
> > > @@ -56,6 +56,7 @@ obj-$(CONFIG_MTD_NAND_BRCMNAND)		+=
> brcmnand/
> > >  obj-$(CONFIG_MTD_NAND_QCOM)		+= qcom_nandc.o
> > >  obj-$(CONFIG_MTD_NAND_MTK)		+= mtk_ecc.o mtk_nand.o
> > >  obj-$(CONFIG_MTD_NAND_TEGRA)		+= tegra_nand.o
> > > +obj-$(CONFIG_MTD_NAND_PL353)		+= pl353_nand.o
> > >
> > >  nand-objs := nand_base.o nand_legacy.o nand_bbt.o nand_timings.o nand_ids.o
> > >  nand-objs += nand_onfi.o
> > > diff --git a/drivers/mtd/nand/raw/pl353_nand.c
> b/drivers/mtd/nand/raw/pl353_nand.c
> > > new file mode 100644
> > > index 0000000..1dbaae5
> > > --- /dev/null
> > > +++ b/drivers/mtd/nand/raw/pl353_nand.c
> > > @@ -0,0 +1,1380 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +/*
> > > + * ARM PL353 NAND flash controller driver
> > > + *
> > > + * Copyright (C) 2017 Xilinx, Inc
> > > + * Author: Punnaiah chowdary kalluri <punnaiah@xilinx.com>
> > > + * Author: Naga Sureshkumar Relli <nagasure@xilinx.com>
> > > + *
> > > + */
> > > +
> > > +#include <linux/err.h>
> > > +#include <linux/delay.h>
> > > +#include <linux/interrupt.h>
> > > +#include <linux/io.h>
> > > +#include <linux/ioport.h>
> > > +#include <linux/irq.h>
> > > +#include <linux/module.h>
> > > +#include <linux/moduleparam.h>
> > > +#include <linux/mtd/mtd.h>
> > > +#include <linux/mtd/rawnand.h>
> > > +#include <linux/mtd/nand_ecc.h>
> > > +#include <linux/mtd/partitions.h>
> > > +#include <linux/of_address.h>
> > > +#include <linux/of_device.h>
> > > +#include <linux/of_platform.h>
> > > +#include <linux/platform_device.h>
> > > +#include <linux/slab.h>
> > > +#include <linux/pl353-smc.h>
> > > +#include <linux/clk.h>
> > > +
> > > +#define PL353_NAND_DRIVER_NAME "pl353-nand"
> > > +
> > > +/* NAND flash driver defines */
> > > +#define PL353_NAND_CMD_PHASE	1	/* End command valid in command
> > phase */
> > > +#define PL353_NAND_DATA_PHASE	2	/* End command valid in data phase
> > */
> > > +#define PL353_NAND_ECC_SIZE	512	/* Size of data for ECC operation */
> > > +
> > > +/* Flash memory controller operating parameters */
> > > +
> > > +#define PL353_NAND_ECC_CONFIG	(BIT(4)  |	/* ECC read at end of page */
> > \
> > > +				 (0 << 5))	/* No Jumping */
> > > +
> > > +/* AXI Address definitions */
> > > +#define START_CMD_SHIFT		3
> > > +#define END_CMD_SHIFT		11
> > > +#define END_CMD_VALID_SHIFT	20
> > > +#define ADDR_CYCLES_SHIFT	21
> > > +#define CLEAR_CS_SHIFT		21
> > > +#define ECC_LAST_SHIFT		10
> > > +#define COMMAND_PHASE		(0 << 19)
> > > +#define DATA_PHASE		BIT(19)
> > > +
> > > +#define PL353_NAND_ECC_LAST	BIT(ECC_LAST_SHIFT)	/* Set
> > ECC_Last */
> > > +#define PL353_NAND_CLEAR_CS	BIT(CLEAR_CS_SHIFT)	/* Clear chip
> > select */
> > > +
> > > +#define PL353_NAND_ECC_BUSY_TIMEOUT	(1 * HZ)
> > > +#define PL353_NAND_DEV_BUSY_TIMEOUT	(1 * HZ)
> > > +#define PL353_NAND_LAST_TRANSFER_LENGTH	4
> > > +#define PL353_NAND_ECC_VALID_SHIFT	24
> > > +#define PL353_NAND_ECC_VALID_MASK	0x40
> > > +#define PL353_ECC_BITS_BYTEOFF_MASK	0x1FF
> > > +#define PL353_ECC_BITS_BITOFF_MASK	0x7
> > > +#define PL353_ECC_BIT_MASK		0xFFF
> > > +#define PL353_TREA_MAX_VALUE		1
> > > +#define PL353_MAX_ECC_CHUNKS		4
> > > +#define PL353_MAX_ECC_BYTES		3
> > > +
> > > +struct pl353_nfc_op {
> > > +	u32 cmnds[4];
> > > +	u32 end_cmd;
> > > +	u32 addrs;
> > > +	u32 naddrs;
> > > +	u32 addr5;
> > > +	u32 addr6;
> > > +	unsigned int data_instr_idx;
> > > +	unsigned int rdy_timeout_ms;
> > > +	unsigned int rdy_delay_ns;
> > > +	unsigned int cle_ale_delay_ns;
> > > +	const struct nand_op_instr *data_instr;
> > > +};
> > > +
> > > +/**
> > > + * struct pl353_nand_controller - Defines the NAND flash controller driver
> > > + *				  instance
> > > + * @chip:		NAND chip information structure
> > > + * @dev:		Parent device (used to print error messages)
> > > + * @regs:		Virtual address of the NAND flash device
> > > + * @buf_addr:		Virtual address of the NAND flash device for
> > > + *			data read/writes
> > > + * @addr_cycles:	Address cycles
> > > + * @mclk:		Memory controller clock
> > > + * @buswidth:		Bus width 8 or 16
> > > + */
> > > +struct pl353_nand_controller {
> > > +	struct nand_controller controller;
> > > +	struct nand_chip chip;
> > > +	struct device *dev;
> > > +	void __iomem *regs;
> > > +	void __iomem *buf_addr;
> > > +	u8 addr_cycles;
> > > +	struct clk *mclk;
> > > +	u32 buswidth;
> > > +};
> > > +
> > > +static int pl353_ecc_ooblayout16_ecc(struct mtd_info *mtd, int section,
> > > +				     struct mtd_oob_region *oobregion)
> > > +{
> > > +	struct nand_chip *chip = mtd_to_nand(mtd);
> > > +
> > > +	if (section >= chip->ecc.steps)
> > > +		return -ERANGE;
> > > +
> > > +	oobregion->offset = (section * chip->ecc.bytes);
> > > +	oobregion->length = chip->ecc.bytes;
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static int pl353_ecc_ooblayout16_free(struct mtd_info *mtd, int section,
> > > +				      struct mtd_oob_region *oobregion)
> > > +{
> > > +	struct nand_chip *chip = mtd_to_nand(mtd);
> > > +
> > > +	if (section >= chip->ecc.steps)
> > > +		return -ERANGE;
> > > +
> > > +	oobregion->offset = (section * chip->ecc.bytes) + 8;
> > > +	oobregion->length = 8;
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static const struct mtd_ooblayout_ops pl353_ecc_ooblayout16_ops = {
> > > +	.ecc = pl353_ecc_ooblayout16_ecc,
> > > +	.free = pl353_ecc_ooblayout16_free,
> > > +};
> > > +
> > > +static int pl353_ecc_ooblayout64_ecc(struct mtd_info *mtd, int section,
> > > +				     struct mtd_oob_region *oobregion)
> > > +{
> > > +	struct nand_chip *chip = mtd_to_nand(mtd);
> > > +
> > > +	if (section >= chip->ecc.steps)
> > > +		return -ERANGE;
> > > +
> > > +	oobregion->offset = (section * chip->ecc.bytes) + 52;
> > > +	oobregion->length = chip->ecc.bytes;
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static int pl353_ecc_ooblayout64_free(struct mtd_info *mtd, int section,
> > > +				      struct mtd_oob_region *oobregion)
> > > +{
> > > +	struct nand_chip *chip = mtd_to_nand(mtd);
> > > +
> > > +	if (section)
> > > +		return -ERANGE;
> > > +
> > > +	if (section >= chip->ecc.steps)
> > > +		return -ERANGE;
> > > +
> > > +	oobregion->offset = (section * chip->ecc.bytes) + 2;
> > > +	oobregion->length = 50;
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static const struct mtd_ooblayout_ops pl353_ecc_ooblayout64_ops = {
> > > +	.ecc = pl353_ecc_ooblayout64_ecc,
> > > +	.free = pl353_ecc_ooblayout64_free,
> > > +};
> > > +
> > > +/* Generic flash bbt decriptors */
> > > +static u8 bbt_pattern[] = { 'B', 'b', 't', '0' };
> > > +static u8 mirror_pattern[] = { '1', 't', 'b', 'B' };
> > > +
> > > +static struct nand_bbt_descr bbt_main_descr = {
> > > +	.options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE |
> > NAND_BBT_WRITE
> > > +		| NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
> > > +	.offs = 4,
> > > +	.len = 4,
> > > +	.veroffs = 20,
> > > +	.maxblocks = 4,
> > > +	.pattern = bbt_pattern
> > > +};
> > > +
> > > +static struct nand_bbt_descr bbt_mirror_descr = {
> > > +	.options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE |
> > NAND_BBT_WRITE
> > > +		| NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
> > > +	.offs = 4,
> > > +	.len = 4,
> > > +	.veroffs = 20,
> > > +	.maxblocks = 4,
> > > +	.pattern = mirror_pattern
> > > +};
> > > +
> > > +static void pl353_nfc_force_byte_access(struct nand_chip *chip,
> > > +					bool force_8bit)
> > > +{
> > > +	struct pl353_nand_controller *xnfc =
> > > +		container_of(chip, struct pl353_nand_controller, chip);
> > > +
> > > +	if (!(chip->options & NAND_BUSWIDTH_16))
> > > +		return;
> > > +
> > > +	if (force_8bit)
> > > +		pl353_smc_set_buswidth(PL353_SMC_MEM_WIDTH_8);
> > > +	else
> > > +		pl353_smc_set_buswidth(PL353_SMC_MEM_WIDTH_16);
> > > +}
> > > +
> > > +/**
> > > + * pl353_nand_read_data_op - read chip data into buffer
> > > + * @chip:	Pointer to the NAND chip info structure
> > > + * @in:		Pointer to the buffer to store read data
> > > + * @len:	Number of bytes to read
> > > + * @force_8bit:	Force 8-bit bus access
> > > + * Return:	Always return zero
> > > + */
> > > +static int pl353_nand_read_data_op(struct nand_chip *chip,
> > > +				   u8 *in,
> > > +				   unsigned int len, bool force_8bit)
> > > +{
> > > +	int i;
> > > +	struct pl353_nand_controller *xnfc =
> > > +		container_of(chip, struct pl353_nand_controller, chip);
> > > +
> > > +	if (force_8bit)
> > > +		pl353_nfc_force_byte_access(chip, true);
> > > +
> > > +	if ((IS_ALIGNED((uint32_t)in, sizeof(uint32_t)) &&
> > > +	     IS_ALIGNED(len, sizeof(uint32_t))) || !force_8bit) {
> > > +		u32 *ptr = (u32 *)in;
> > > +
> > > +		len /= 4;
> > > +		for (i = 0; i < len; i++)
> > > +			ptr[i] = readl(xnfc->buf_addr);
> > > +	} else {
> > > +		for (i = 0; i < len; i++)
> > > +			in[i] = readb(xnfc->buf_addr);
> > > +	}
> > > +	if (force_8bit)
> > > +		pl353_nfc_force_byte_access(chip, false);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +/**
> > > + * pl353_nand_write_buf - write buffer to chip
> > > + * @mtd:	Pointer to the mtd info structure
> > > + * @buf:	Pointer to the buffer to store write data
> > > + * @len:	Number of bytes to write
> > > + * @force_8bit:	Force 8-bit bus access
> > > + */
> > > +static void pl353_nand_write_data_op(struct nand_chip *chip, const u8 *buf,
> > > +				     int len, bool force_8bit)
> > > +{
> > > +	int i;
> > > +	struct pl353_nand_controller *xnfc =
> > > +		container_of(chip, struct pl353_nand_controller, chip);
> > > +
> > > +	if (force_8bit)
> > > +		pl353_nfc_force_byte_access(chip, true);
> > > +
> > > +	if ((IS_ALIGNED((uint32_t)buf, sizeof(uint32_t)) &&
> > > +	     IS_ALIGNED(len, sizeof(uint32_t))) || !force_8bit) {
> > > +		u32 *ptr = (u32 *)buf;
> > > +
> > > +		len /= 4;
> > > +		for (i = 0; i < len; i++)
> > > +			writel(ptr[i], xnfc->buf_addr);
> > > +	} else {
> > > +		for (i = 0; i < len; i++)
> > > +			writeb(buf[i], xnfc->buf_addr);
> > > +	}
> > > +	if (force_8bit)
> > > +		pl353_nfc_force_byte_access(chip, false);
> > > +}
> > > +
> > > +static int pl353_wait_for_ecc_done(void)
> > > +{
> > > +	unsigned long timeout = jiffies + PL353_NAND_ECC_BUSY_TIMEOUT;
> > > +
> > > +	do {
> > > +		if (pl353_smc_ecc_is_busy())
> > > +			cpu_relax();
> > > +		else
> > > +			break;
> > > +	} while (!time_after_eq(jiffies, timeout));
> > > +
> > > +	if (time_after_eq(jiffies, timeout)) {
> > > +		pr_err("%s timed out\n", __func__);
> > > +		return -ETIMEDOUT;
> > > +	}
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +/**
> > > + * pl353_nand_calculate_hwecc - Calculate Hardware ECC
> > > + * @mtd:	Pointer to the mtd_info structure
> > > + * @data:	Pointer to the page data
> > > + * @ecc:	Pointer to the ECC buffer where ECC data needs to be stored
> > > + *
> > > + * This function retrieves the Hardware ECC data from the controller and returns
> > > + * ECC data back to the MTD subsystem.
> > > + * It operates on a number of 512 byte blocks of NAND memory and can be
> > > + * programmed to store the ECC codes after the data in memory. For writes,
> > > + * the ECC is written to the spare area of the page. For reads, the result of
> > > + * a block ECC check are made available to the device driver.
> > > + *
> > > + * ------------------------------------------------------------------------
> > > + * |               n * 512 blocks                  | extra  | ecc    |     |
> > > + * |                                               | block  | codes  |     |
> > > + * ------------------------------------------------------------------------
> > > + *
> > > + * The ECC calculation uses a simple Hamming code, using 1-bit correction 2-bit
> > > + * detection. It starts when a valid read or write command with a 512 byte
> > > + * aligned address is detected on the memory interface.
> > > + *
> > > + * Return:	0 on success or error value on failure
> > > + */
> > > +static int pl353_nand_calculate_hwecc(struct nand_chip *chip,
> > > +				      const u8 *data, u8 *ecc)
> > > +{
> > > +	u32 ecc_value;
> > > +	u8 chunk, ecc_byte, ecc_status;
> > > +
> > > +	for (chunk = 0; chunk < PL353_MAX_ECC_CHUNKS; chunk++) {
> > > +		/* Read ECC value for each block */
> > > +		ecc_value = pl353_smc_get_ecc_val(chunk);
> > > +		ecc_status = (ecc_value >> PL353_NAND_ECC_VALID_SHIFT);
> > > +
> > > +		/* ECC value valid */
> > > +		if (ecc_status & PL353_NAND_ECC_VALID_MASK) {
> > > +			for (ecc_byte = 0; ecc_byte < PL353_MAX_ECC_BYTES;
> > > +			     ecc_byte++) {
> > > +				/* Copy ECC bytes to MTD buffer */
> > > +				*ecc = ~ecc_value & 0xFF;
> > > +				ecc_value = ecc_value >> 8;
> > > +				ecc++;
> > > +			}
> > > +		} else {
> > > +			pr_warn("%s status failed\n", __func__);
> > > +			return -1;
> > > +		}
> > > +	}
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +/**
> > > + * pl353_nand_correct_data - ECC correction function
> > > + * @mtd:	Pointer to the mtd_info structure
> > > + * @buf:	Pointer to the page data
> > > + * @read_ecc:	Pointer to the ECC value read from spare data area
> > > + * @calc_ecc:	Pointer to the calculated ECC value
> > > + *
> > > + * This function corrects the ECC single bit errors & detects 2-bit errors.
> > > + *
> > > + * Return:	0 if no ECC errors found
> > > + *		1 if single bit error found and corrected.
> > > + *		-1 if multiple uncorrectable ECC errors found.
> > > + */
> > > +static int pl353_nand_correct_data(struct nand_chip *chip, unsigned char *buf,
> > > +				   unsigned char *read_ecc,
> > > +				   unsigned char *calc_ecc)
> >
> > Isn't it a regular Hamming software ECC algorithm? Can't you re-use the
> > implementation already existing?
> This is called from pl353_nand_read_page_hwecc to check the errors using
> chip->ecc.correct(mtd, p, &ecc_code[i], &ecc_calc[i]), once the page read(hwecc) is done.
> And this needs some custom masks defined below.
> >
> > > +{
> > > +	unsigned char bit_addr;
> > > +	unsigned int byte_addr;
> > > +	unsigned short ecc_odd, ecc_even, read_ecc_lower, read_ecc_upper;
> > > +	unsigned short calc_ecc_lower, calc_ecc_upper;
> > > +
> > > +	read_ecc_lower = (read_ecc[0] | (read_ecc[1] << 8)) &
> > > +			  PL353_ECC_BIT_MASK;
> > > +	read_ecc_upper = ((read_ecc[1] >> 4) | (read_ecc[2] << 4)) &
> > > +			  PL353_ECC_BIT_MASK;
> > > +
> > > +	calc_ecc_lower = (calc_ecc[0] | (calc_ecc[1] << 8)) &
> > > +			  PL353_ECC_BIT_MASK;
> > > +	calc_ecc_upper = ((calc_ecc[1] >> 4) | (calc_ecc[2] << 4)) &
> > > +			  PL353_ECC_BIT_MASK;
> > > +
> > > +	ecc_odd = read_ecc_lower ^ calc_ecc_lower;
> > > +	ecc_even = read_ecc_upper ^ calc_ecc_upper;
> > > +
> > > +	/* no error */
> > > +	if (!ecc_odd && !ecc_even)
> > > +		return 0;
> > > +
> > > +	if (ecc_odd == (~ecc_even & PL353_ECC_BIT_MASK)) {
> > > +		/* bits [11:3] of error code is byte offset */
> > > +		byte_addr = (ecc_odd >> 3) & PL353_ECC_BITS_BYTEOFF_MASK;
> > > +		/* bits [2:0] of error code is bit offset */
> > > +		bit_addr = ecc_odd & PL353_ECC_BITS_BITOFF_MASK;
> > > +		/* Toggling error bit */
> > > +		buf[byte_addr] ^= (BIT(bit_addr));
> > > +		return 1;
> > > +	}
> > > +
> > > +	/* one error in parity */
> > > +	if (hweight32(ecc_odd | ecc_even) == 1)
> > > +		return 1;
> > > +
> > > +	/* Uncorrectable error */
> > > +	return -1;
> > > +}
> > > +
> > > +static void pl353_prepare_cmd(struct nand_chip *chip,
> > > +			      int page, int column, int start_cmd, int end_cmd,
> > > +			      bool read)
> > > +{
> > > +	unsigned long data_phase_addr;
> > > +	u32 end_cmd_valid = 0;
> > > +	unsigned long cmd_phase_addr = 0, cmd_phase_data = 0;
> > > +	struct mtd_info *mtd = nand_to_mtd(chip);
> > > +
> > > +	struct pl353_nand_controller *xnfc =
> > > +		container_of(chip, struct pl353_nand_controller, chip);
> > > +
> > > +	end_cmd_valid = read ? 1 : 0;
> > > +
> > > +	cmd_phase_addr = (unsigned long __force)xnfc->regs +
> > > +			 ((xnfc->addr_cycles
> > > +			 << ADDR_CYCLES_SHIFT) |
> > > +			 (end_cmd_valid << END_CMD_VALID_SHIFT) |
> > > +			 (COMMAND_PHASE) |
> > > +			 (end_cmd << END_CMD_SHIFT) |
> > > +			 (start_cmd << START_CMD_SHIFT));
> > > +
> > > +	/* Get the data phase address */
> > > +	data_phase_addr = (unsigned long __force)xnfc->regs +
> > > +			  ((0x0 << CLEAR_CS_SHIFT) |
> > > +			  (0 << END_CMD_VALID_SHIFT) |
> > > +			  (DATA_PHASE) |
> > > +			  (end_cmd << END_CMD_SHIFT) |
> > > +			  (0x0 << ECC_LAST_SHIFT));
> > > +
> > > +	xnfc->buf_addr = (void __iomem * __force)data_phase_addr;
> > > +
> > > +	if (chip->options & NAND_BUSWIDTH_16)
> > > +		column /= 2;
> > > +	cmd_phase_data = column;
> > > +	if (mtd->writesize > PL353_NAND_ECC_SIZE) {
> > > +		cmd_phase_data |= page << 16;
> > > +		/* Another address cycle for devices > 128MiB */
> > > +		if (chip->options & NAND_ROW_ADDR_3) {
> > > +			writel_relaxed(cmd_phase_data,
> > > +				       (void __iomem * __force)cmd_phase_addr);
> > > +			cmd_phase_data = (page >> 16);
> > > +		}
> > > +	} else {
> > > +		cmd_phase_data |= page << 8;
> > > +	}
> > > +
> > > +	writel_relaxed(cmd_phase_data, (void __iomem * __force)cmd_phase_addr);
> > > +}
> > > +
> > > +/**
> > > + * pl353_nand_read_oob - [REPLACEABLE] the most common OOB data read
> function
> > > + * @mtd:	Pointer to the mtd_info structure
> > > + * @chip:	Pointer to the nand_chip structure
> > > + * @page:	Page number to read
> > > + *
> > > + * Return:	Always return zero
> > > + */
> > > +static int pl353_nand_read_oob(struct nand_chip *chip,
> > > +			       int page)
> > > +{
> > > +	unsigned long data_phase_addr;
> > > +	u8 *p;
> > > +	struct pl353_nand_controller *xnfc =
> > > +		container_of(chip, struct pl353_nand_controller, chip);
> > > +	unsigned long nand_offset = (unsigned long __force)xnfc->regs;
> > > +	struct mtd_info *mtd = nand_to_mtd(chip);
> > > +
> > > +	chip->pagebuf = -1;
> > > +	if (mtd->writesize < PL353_NAND_ECC_SIZE)
> > > +		return 0;
> > > +
> > > +	pl353_prepare_cmd(chip, page, mtd->writesize, NAND_CMD_READ0,
> > > +			  NAND_CMD_READSTART, 1);
> > > +
> > > +	nand_wait_ready(chip);
> > > +
> > > +	p = chip->oob_poi;
> > > +	pl353_nand_read_data_op(chip, p,
> > > +				(mtd->oobsize -
> > > +				PL353_NAND_LAST_TRANSFER_LENGTH), false);
> > > +	p += (mtd->oobsize - PL353_NAND_LAST_TRANSFER_LENGTH);
> > > +	data_phase_addr = (unsigned long __force)xnfc->buf_addr;
> > > +	data_phase_addr -= nand_offset;
> > > +	data_phase_addr |= PL353_NAND_CLEAR_CS;
> > > +	data_phase_addr += nand_offset;
> > > +	xnfc->buf_addr = (void __iomem * __force)data_phase_addr;
> > > +	pl353_nand_read_data_op(chip, p, PL353_NAND_LAST_TRANSFER_LENGTH,
> > > +				false);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +/**
> > > + * pl353_nand_write_oob - [REPLACEABLE] the most common OOB data write
> > function
> > > + * @mtd:	Pointer to the mtd info structure
> > > + * @chip:	Pointer to the NAND chip info structure
> > > + * @page:	Page number to write
> > > + *
> > > + * Return:	Zero on success and EIO on failure
> > > + */
> > > +static int pl353_nand_write_oob(struct nand_chip *chip,
> > > +				int page)
> > > +{
> > > +	const u8 *buf = chip->oob_poi;
> > > +	unsigned long data_phase_addr;
> > > +	struct pl353_nand_controller *xnfc =
> > > +		container_of(chip, struct pl353_nand_controller, chip);
> > > +	unsigned long nand_offset = (unsigned long __force)xnfc->regs;
> > > +	struct mtd_info *mtd = nand_to_mtd(chip);
> > > +	u32 addrcycles = 0;
> > > +
> > > +	chip->pagebuf = -1;
> > > +	addrcycles = xnfc->addr_cycles;
> > > +	pl353_prepare_cmd(chip, page, mtd->writesize, NAND_CMD_SEQIN,
> > > +			  NAND_CMD_PAGEPROG, 0);
> > > +
> > > +	pl353_nand_write_data_op(chip, buf,
> > > +				 (mtd->oobsize -
> > > +				 PL353_NAND_LAST_TRANSFER_LENGTH), false);
> > > +	buf += (mtd->oobsize - PL353_NAND_LAST_TRANSFER_LENGTH);
> > > +
> > > +	data_phase_addr = (unsigned long __force)xnfc->buf_addr;
> > > +	data_phase_addr -= nand_offset;
> > > +	data_phase_addr |= PL353_NAND_CLEAR_CS;
> > > +	data_phase_addr |= (1 << END_CMD_VALID_SHIFT);
> > > +	data_phase_addr += nand_offset;
> > > +	xnfc->buf_addr = (void __iomem * __force)data_phase_addr;
> > > +	pl353_nand_write_data_op(chip, buf, PL353_NAND_LAST_TRANSFER_LENGTH,
> > > +				 false);
> > > +	nand_wait_ready(chip);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +/**
> > > + * pl353_nand_read_page_raw - [Intern] read raw page data without ecc
> > > + * @mtd:		Pointer to the mtd info structure
> > > + * @chip:		Pointer to the NAND chip info structure
> > > + * @buf:		Pointer to the data buffer
> > > + * @oob_required:	Caller requires OOB data read to chip->oob_poi
> > > + * @page:		Page number to read
> > > + *
> > > + * Return:	Always return zero
> > > + */
> > > +static int pl353_nand_read_page_raw(struct nand_chip *chip,
> > > +				    u8 *buf, int oob_required, int page)
> > > +{
> > > +	unsigned long data_phase_addr;
> > > +	u8 *p;
> > > +	struct pl353_nand_controller *xnfc =
> > > +		container_of(chip, struct pl353_nand_controller, chip);
> > > +	unsigned long nand_offset = (unsigned long __force)xnfc->regs;
> > > +	struct mtd_info *mtd = nand_to_mtd(chip);
> > > +
> > > +	pl353_prepare_cmd(chip, page, 0, NAND_CMD_READ0,
> > > +			  NAND_CMD_READSTART, 1);
> > > +	nand_wait_ready(chip);
> > > +	pl353_nand_read_data_op(chip, buf, mtd->writesize, false);
> > > +	p = chip->oob_poi;
> > > +	pl353_nand_read_data_op(chip, p,
> > > +				(mtd->oobsize -
> > > +				PL353_NAND_LAST_TRANSFER_LENGTH), false);
> > > +	p += (mtd->oobsize - PL353_NAND_LAST_TRANSFER_LENGTH);
> > > +
> > > +	data_phase_addr = (unsigned long __force)xnfc->buf_addr;
> > > +	data_phase_addr -= nand_offset;
> > > +	data_phase_addr |= PL353_NAND_CLEAR_CS;
> > > +	data_phase_addr += nand_offset;
> > > +	xnfc->buf_addr = (void __iomem * __force)data_phase_addr;
> > > +
> > > +	pl353_nand_read_data_op(chip, p, PL353_NAND_LAST_TRANSFER_LENGTH,
> > > +				false);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +/**
> > > + * pl353_nand_write_page_raw - [Intern] raw page write function
> > > + * @mtd:		Pointer to the mtd info structure
> > > + * @chip:		Pointer to the NAND chip info structure
> > > + * @buf:		Pointer to the data buffer
> > > + * @oob_required:	Caller requires OOB data read to chip->oob_poi
> > > + * @page:		Page number to write
> > > + *
> > > + * Return:	Always return zero
> > > + */
> > > +static int pl353_nand_write_page_raw(struct nand_chip *chip,
> > > +				     const u8 *buf, int oob_required,
> > > +				     int page)
> > > +{
> > > +	unsigned long data_phase_addr;
> > > +	u8 *p;
> > > +	struct pl353_nand_controller *xnfc =
> > > +		container_of(chip, struct pl353_nand_controller, chip);
> > > +	unsigned long nand_offset = (unsigned long __force)xnfc->regs;
> > > +	struct mtd_info *mtd = nand_to_mtd(chip);
> > > +
> > > +	pl353_prepare_cmd(chip, page, 0, NAND_CMD_SEQIN,
> > > +			  NAND_CMD_PAGEPROG, 0);
> > > +	pl353_nand_write_data_op(chip, buf, mtd->writesize, false);
> > > +	p = chip->oob_poi;
> > > +	pl353_nand_write_data_op(chip, p,
> > > +				 (mtd->oobsize -
> > > +				 PL353_NAND_LAST_TRANSFER_LENGTH), false);
> > > +	p += (mtd->oobsize - PL353_NAND_LAST_TRANSFER_LENGTH);
> > > +
> > > +	data_phase_addr = (unsigned long __force)xnfc->buf_addr;
> > > +	data_phase_addr -= nand_offset;
> > > +	data_phase_addr |= PL353_NAND_CLEAR_CS;
> > > +	data_phase_addr |= (1 << END_CMD_VALID_SHIFT);
> > > +	data_phase_addr += nand_offset;
> > > +	xnfc->buf_addr = (void __iomem * __force)data_phase_addr;
> > > +	pl353_nand_write_data_op(chip, p, PL353_NAND_LAST_TRANSFER_LENGTH,
> > > +				 false);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +/**
> > > + * nand_write_page_hwecc - Hardware ECC based page write function
> > > + * @mtd:		Pointer to the mtd info structure
> > > + * @chip:		Pointer to the NAND chip info structure
> > > + * @buf:		Pointer to the data buffer
> > > + * @oob_required:	Caller requires OOB data read to chip->oob_poi
> > > + * @page:		Page number to write
> > > + *
> > > + * This functions writes data and hardware generated ECC values in to the page.
> > > + *
> > > + * Return:	Always return zero
> > > + */
> > > +static int pl353_nand_write_page_hwecc(struct nand_chip *chip,
> > > +				       const u8 *buf, int oob_required,
> > > +				       int page)
> > > +{
> > > +	int eccsize = chip->ecc.size;
> > > +	int eccsteps = chip->ecc.steps;
> > > +	u8 *ecc_calc = chip->ecc.calc_buf;
> > > +	u8 *oob_ptr;
> > > +	const u8 *p = buf;
> > > +	u32 ret;
> > > +	unsigned long data_phase_addr;
> > > +	struct pl353_nand_controller *xnfc =
> > > +		container_of(chip, struct pl353_nand_controller, chip);
> > > +	unsigned long nand_offset = (unsigned long __force)xnfc->regs;
> > > +	struct mtd_info *mtd = nand_to_mtd(chip);
> > > +
> > > +	pl353_prepare_cmd(chip, page, 0, NAND_CMD_SEQIN,
> > > +			  NAND_CMD_PAGEPROG, 0);
> > > +
> > > +	for ( ; (eccsteps - 1); eccsteps--) {
> > > +		pl353_nand_write_data_op(chip, p, eccsize, false);
> > > +		p += eccsize;
> > > +	}
> > > +	pl353_nand_write_data_op(chip, p,
> > > +				 (eccsize - PL353_NAND_LAST_TRANSFER_LENGTH),
> > > +				 false);
> > > +	p += (eccsize - PL353_NAND_LAST_TRANSFER_LENGTH);
> > > +
> > > +	/* Set ECC Last bit to 1 */
> > > +	data_phase_addr = (unsigned long __force)xnfc->buf_addr;
> > > +	data_phase_addr -= nand_offset;
> > > +	data_phase_addr |= PL353_NAND_ECC_LAST;
> > > +	data_phase_addr += nand_offset;
> > > +	xnfc->buf_addr = (void __iomem * __force)data_phase_addr;
> > > +	pl353_nand_write_data_op(chip, p, PL353_NAND_LAST_TRANSFER_LENGTH,
> > > +				 false);
> > > +
> > > +	/* Wait till the ECC operation is complete or timeout */
> > > +	ret = pl353_wait_for_ecc_done();
> > > +	if (ret)
> > > +		dev_err(xnfc->dev, "ECC Timeout\n");
> > > +	p = buf;
> > > +	ret = chip->ecc.calculate(chip, p, &ecc_calc[0]);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	/* Wait for ECC to be calculated and read the error values */
> > > +	ret = mtd_ooblayout_set_eccbytes(mtd, ecc_calc, chip->oob_poi,
> > > +					 0, chip->ecc.total);
> > > +	if (ret)
> > > +		return ret;
> > > +	/* Clear ECC last bit */
> > > +	data_phase_addr = (unsigned long __force)xnfc->buf_addr;
> > > +	data_phase_addr -= nand_offset;
> > > +	data_phase_addr &= ~PL353_NAND_ECC_LAST;
> > > +	data_phase_addr += nand_offset;
> > > +	xnfc->buf_addr = (void __iomem * __force)data_phase_addr;
> > > +
> > > +	/* Write the spare area with ECC bytes */
> > > +	oob_ptr = chip->oob_poi;
> > > +	pl353_nand_write_data_op(chip, oob_ptr,
> > > +				 (mtd->oobsize -
> > > +				 PL353_NAND_LAST_TRANSFER_LENGTH), false);
> > > +
> > > +	data_phase_addr = (unsigned long __force)xnfc->buf_addr;
> > > +	data_phase_addr -= nand_offset;
> > > +	data_phase_addr |= PL353_NAND_CLEAR_CS;
> > > +	data_phase_addr |= (1 << END_CMD_VALID_SHIFT);
> > > +	data_phase_addr += nand_offset;
> > > +	xnfc->buf_addr = (void __iomem * __force)data_phase_addr;
> > > +	oob_ptr += (mtd->oobsize - PL353_NAND_LAST_TRANSFER_LENGTH);
> > > +	pl353_nand_write_data_op(chip, oob_ptr,
> > PL353_NAND_LAST_TRANSFER_LENGTH,
> > > +				 false);
> > > +	nand_wait_ready(chip);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +/**
> > > + * pl353_nand_read_page_hwecc - Hardware ECC based page read function
> > > + * @mtd:		Pointer to the mtd info structure
> > > + * @chip:		Pointer to the NAND chip info structure
> > > + * @buf:		Pointer to the buffer to store read data
> > > + * @oob_required:	Caller requires OOB data read to chip->oob_poi
> > > + * @page:		Page number to read
> > > + *
> > > + * This functions reads data and checks the data integrity by comparing
> > > + * hardware generated ECC values and read ECC values from spare area.
> > > + * There is a limitation in SMC controller, that we must set ECC LAST on
> > > + * last data phase access, to tell ECC block not to expect any data further.
> > > + * Ex:  When number of ECC STEPS are 4, then till 3 we will write to flash
> > > + * using SMC with HW ECC enabled. And for the last ECC STEP, we will subtract
> > > + * 4bytes from page size, and will initiate a transfer. And the remaining 4 as
> > > + * one more transfer with ECC_LAST bit set in NAND data phase register to
> > > + * notify ECC block not to expect any more data. The last block should be align
> > > + * with end of 512 byte block. Because of this limitation, we are not using
> > > + * core routines.
> > > + *
> > > + * Return:	0 always and updates ECC operation status in to MTD structure
> > > + */
> > > +static int pl353_nand_read_page_hwecc(struct nand_chip *chip,
> > > +				      u8 *buf, int oob_required, int page)
> > > +{
> > > +	int i, stat, eccsize = chip->ecc.size;
> > > +	int eccbytes = chip->ecc.bytes;
> > > +	int eccsteps = chip->ecc.steps;
> > > +	u8 *p = buf;
> > > +	u8 *ecc_calc = chip->ecc.calc_buf;
> > > +	u8 *ecc = chip->ecc.code_buf;
> > > +	unsigned int max_bitflips = 0;
> > > +	u8 *oob_ptr;
> > > +	u32 ret;
> > > +	unsigned long data_phase_addr;
> > > +	struct pl353_nand_controller *xnfc =
> > > +		container_of(chip, struct pl353_nand_controller, chip);
> > > +	unsigned long nand_offset = (unsigned long __force)xnfc->regs;
> > > +	struct mtd_info *mtd = nand_to_mtd(chip);
> > > +
> > > +	pl353_prepare_cmd(chip, page, 0, NAND_CMD_READ0,
> > > +			  NAND_CMD_READSTART, 1);
> > > +	nand_wait_ready(chip);
> > > +
> > > +	for ( ; (eccsteps - 1); eccsteps--) {
> > > +		pl353_nand_read_data_op(chip, p, eccsize, false);
> > > +		p += eccsize;
> > > +	}
> > > +	pl353_nand_read_data_op(chip, p,
> > > +				(eccsize - PL353_NAND_LAST_TRANSFER_LENGTH),
> > > +				false);
> > > +	p += (eccsize - PL353_NAND_LAST_TRANSFER_LENGTH);
> > > +
> > > +	/* Set ECC Last bit to 1 */
> > > +	data_phase_addr = (unsigned long __force)xnfc->buf_addr;
> > > +	data_phase_addr -= nand_offset;
> > > +	data_phase_addr |= PL353_NAND_ECC_LAST;
> > > +	data_phase_addr += nand_offset;
> > > +	xnfc->buf_addr = (void __iomem * __force)data_phase_addr;
> > > +	pl353_nand_read_data_op(chip, p, PL353_NAND_LAST_TRANSFER_LENGTH,
> > > +				false);
> > > +
> > > +	/* Wait till the ECC operation is complete or timeout */
> > > +	ret = pl353_wait_for_ecc_done();
> > > +	if (ret)
> > > +		dev_err(xnfc->dev, "ECC Timeout\n");
> > > +
> > > +	/* Read the calculated ECC value */
> > > +	p = buf;
> > > +	ret = chip->ecc.calculate(chip, p, &ecc_calc[0]);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	/* Clear ECC last bit */
> > > +	data_phase_addr = (unsigned long __force)xnfc->buf_addr;
> > > +	data_phase_addr -= nand_offset;
> > > +	data_phase_addr &= ~PL353_NAND_ECC_LAST;
> > > +	data_phase_addr += nand_offset;
> > > +	xnfc->buf_addr = (void __iomem * __force)data_phase_addr;
> > > +
> > > +	/* Read the stored ECC value */
> > > +	oob_ptr = chip->oob_poi;
> > > +	pl353_nand_read_data_op(chip, oob_ptr,
> > > +				(mtd->oobsize -
> > > +				PL353_NAND_LAST_TRANSFER_LENGTH), false);
> > > +
> > > +	/* de-assert chip select */
> > > +	data_phase_addr = (unsigned long __force)xnfc->buf_addr;
> > > +	data_phase_addr -= nand_offset;
> > > +	data_phase_addr |= PL353_NAND_CLEAR_CS;
> > > +	data_phase_addr += nand_offset;
> > > +	xnfc->buf_addr = (void __iomem * __force)data_phase_addr;
> > > +
> > > +	oob_ptr += (mtd->oobsize - PL353_NAND_LAST_TRANSFER_LENGTH);
> > > +	pl353_nand_read_data_op(chip, oob_ptr,
> > PL353_NAND_LAST_TRANSFER_LENGTH,
> > > +				false);
> > > +
> > > +	ret = mtd_ooblayout_get_eccbytes(mtd, ecc, chip->oob_poi, 0,
> > > +					 chip->ecc.total);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	eccsteps = chip->ecc.steps;
> > > +	p = buf;
> > > +
> > > +	/* Check ECC error for all blocks and correct if it is correctable */
> > > +	for (i = 0 ; eccsteps; eccsteps--, i += eccbytes, p += eccsize) {
> > > +		stat = chip->ecc.correct(chip, p, &ecc[i], &ecc_calc[i]);
> > > +		if (stat < 0) {
> > > +			mtd->ecc_stats.failed++;
> > > +		} else {
> > > +			mtd->ecc_stats.corrected += stat;
> > > +			max_bitflips = max_t(unsigned int, max_bitflips, stat);
> > > +		}
> > > +	}
> > > +
> > > +	return max_bitflips;
> > > +}
> > > +
> > > +/* NAND framework ->exec_op() hooks and related helpers */
> > > +static void pl353_nfc_parse_instructions(struct nand_chip *chip,
> > > +					 const struct nand_subop *subop,
> > > +					 struct pl353_nfc_op *nfc_op)
> > > +{
> > > +	const struct nand_op_instr *instr = NULL;
> > > +	unsigned int op_id, offset, naddrs;
> > > +	int i;
> > > +	const u8 *addrs;
> > > +
> > > +	memset(nfc_op, 0, sizeof(struct pl353_nfc_op));
> > > +	for (op_id = 0; op_id < subop->ninstrs; op_id++) {
> > > +		instr = &subop->instrs[op_id];
> > > +
> > > +		switch (instr->type) {
> > > +		case NAND_OP_CMD_INSTR:
> > > +			if (op_id)
> > > +				nfc_op->cmnds[1] = instr->ctx.cmd.opcode;
> > > +			else
> > > +				nfc_op->cmnds[0] = instr->ctx.cmd.opcode;
> > > +			nfc_op->cle_ale_delay_ns = instr->delay_ns;
> > > +			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->addrs = instr->ctx.addr.addrs[offset];
> > > +			for (i = 0; i < min_t(unsigned int, 4, naddrs); i++) {
> > > +				nfc_op->addrs |= instr->ctx.addr.addrs[i] <<
> > > +						 (8 * i);
> > > +			}
> > > +
> > > +			if (naddrs >= 5)
> > > +				nfc_op->addr5 = addrs[4];
> > > +			if (naddrs >= 6)
> > > +				nfc_op->addr6 = addrs[5];
> > > +			nfc_op->naddrs = nand_subop_get_num_addr_cyc(subop,
> > > +								     op_id);
> > > +			nfc_op->cle_ale_delay_ns = instr->delay_ns;
> > > +			break;
> > > +
> > > +		case NAND_OP_DATA_IN_INSTR:
> > > +			nfc_op->data_instr = instr;
> > > +			nfc_op->data_instr_idx = op_id;
> > > +			break;
> > > +
> > > +		case NAND_OP_DATA_OUT_INSTR:
> > > +			nfc_op->data_instr = instr;
> > > +			nfc_op->data_instr_idx = op_id;
> > > +			break;
> > > +
> > > +		case NAND_OP_WAITRDY_INSTR:
> > > +			nfc_op->rdy_timeout_ms = instr->ctx.waitrdy.timeout_ms;
> > > +			nfc_op->rdy_delay_ns = instr->delay_ns;
> > > +			break;
> > > +		}
> > > +	}
> > > +}
> > > +
> > > +static void cond_delay(unsigned int ns)
> > > +{
> > > +	if (!ns)
> > > +		return;
> > > +
> > > +	if (ns < 10000)
> > > +		ndelay(ns);
> > > +	else
> > > +		udelay(DIV_ROUND_UP(ns, 1000));
> > > +}
> > > +
> > > +/**
> > > + * pl353_nand_exec_op_cmd - Send command to NAND device
> > > + * @chip:	Pointer to the NAND chip info structure
> > > + * @subop:	Pointer to array of instructions
> > > + * Return:	Always return zero
> > > + */
> > > +static int pl353_nand_exec_op_cmd(struct nand_chip *chip,
> > > +				  const struct nand_subop *subop)
> > > +{
> > > +	struct mtd_info *mtd = nand_to_mtd(chip);
> > > +	const struct nand_op_instr *instr;
> > > +	struct pl353_nfc_op nfc_op = {};
> > > +	struct pl353_nand_controller *xnfc =
> > > +		container_of(chip, struct pl353_nand_controller, chip);
> > > +	unsigned long cmd_phase_data = 0, end_cmd_valid = 0;
> > > +	unsigned long cmd_phase_addr, data_phase_addr, end_cmd;
> > > +	unsigned int op_id, len, offset;
> > > +	bool reading;
> > > +
> > > +	pl353_nfc_parse_instructions(chip, subop, &nfc_op);
> > > +	instr = nfc_op.data_instr;
> > > +	op_id = nfc_op.data_instr_idx;
> > > +
> > > +	offset = nand_subop_get_data_start_off(subop, op_id);
> > > +
> > > +	pl353_smc_clr_nand_int();
> > > +	/* Get the command phase address */
> > > +	if (nfc_op.cmnds[1] != 0) {
> > > +		if (nfc_op.cmnds[0] == NAND_CMD_SEQIN)
> > > +			end_cmd_valid = 0;
> > > +		else
> > > +			end_cmd_valid = 1;
> > > +		end_cmd = nfc_op.cmnds[1];
> > > +	}  else {
> > > +		end_cmd = 0x0;
> > > +	}
> > > +
> > > +	/*
> > > +	 * The SMC defines two phases of commands when transferring data to or
> > > +	 * from NAND flash.
> > > +	 * Command phase: Commands and optional address information are written
> > > +	 * to the NAND flash.The command and address can be associated with
> > > +	 * either a data phase operation to write to or read from the array,
> > > +	 * or a status/ID register transfer.
> > > +	 * Data phase: Data is either written to or read from the NAND flash.
> > > +	 * This data can be either data transferred to or from the array,
> > > +	 * or status/ID register information.
> > > +	 */
> > > +	cmd_phase_addr = (unsigned long __force)xnfc->regs +
> > > +			 ((nfc_op.naddrs << ADDR_CYCLES_SHIFT) |
> > > +			 (end_cmd_valid << END_CMD_VALID_SHIFT) |
> > > +			 (COMMAND_PHASE) |
> > > +			 (end_cmd << END_CMD_SHIFT) |
> > > +			 (nfc_op.cmnds[0] << START_CMD_SHIFT));
> > > +
> > > +	/* Get the data phase address */
> > > +	end_cmd_valid = 0;
> > > +
> > > +	data_phase_addr = (unsigned long __force)xnfc->regs +
> > > +			  ((0x0 << CLEAR_CS_SHIFT) |
> > > +			  (end_cmd_valid << END_CMD_VALID_SHIFT) |
> > > +			  (DATA_PHASE) |
> > > +			  (end_cmd << END_CMD_SHIFT) |
> > > +			  (0x0 << ECC_LAST_SHIFT));
> > > +	xnfc->buf_addr = (void __iomem * __force)data_phase_addr;
> > > +
> > > +	/* Command phase AXI Read & Write */
> > > +	if (nfc_op.naddrs >= 5) {
> > > +		if (mtd->writesize > PL353_NAND_ECC_SIZE) {
> > > +			cmd_phase_data = nfc_op.addrs;
> > > +			/* Another address cycle for devices > 128MiB */
> > > +			if (chip->options & NAND_ROW_ADDR_3) {
> > > +				writel_relaxed(cmd_phase_data,
> > > +					       (void __iomem * __force)
> > > +					       cmd_phase_addr);
> > > +				cmd_phase_data = nfc_op.addr5;
> > > +				if (nfc_op.naddrs >= 6)
> > > +					cmd_phase_data |= (nfc_op.addr6 << 8);
> > > +			}
> > > +		}
> > > +	}  else {
> > > +		if (nfc_op.addrs != -1) {
> > > +			int column = nfc_op.addrs;
> > > +			/*
> > > +			 * Change read/write column, read id etc
> > > +			 * Adjust columns for 16 bit bus width
> > > +			 */
> > > +			if ((chip->options & NAND_BUSWIDTH_16) &&
> > > +			    (nfc_op.cmnds[0] == NAND_CMD_READ0 ||
> > > +				nfc_op.cmnds[0] == NAND_CMD_SEQIN ||
> > > +				nfc_op.cmnds[0] == NAND_CMD_RNDOUT ||
> > > +				nfc_op.cmnds[0] == NAND_CMD_RNDIN)) {
> > > +				column >>= 1;
> > > +			}
> > > +			cmd_phase_data = column;
> > > +		}
> > > +	}
> > > +	writel_relaxed(cmd_phase_data, (void __iomem * __force)cmd_phase_addr);
> > > +
> > > +	if (!nfc_op.data_instr) {
> > > +		if (nfc_op.rdy_timeout_ms)
> > > +			nand_wait_ready(chip);
> > > +		return 0;
> > > +	}
> > > +
> > > +	reading = (nfc_op.data_instr->type == NAND_OP_DATA_IN_INSTR);
> > > +	if (!reading) {
> > > +		len = nand_subop_get_data_len(subop, op_id);
> > > +		pl353_nand_write_data_op(chip, instr->ctx.data.buf.out,
> > > +					 len, instr->ctx.data.force_8bit);
> > > +		if (nfc_op.rdy_timeout_ms)
> > > +			nand_wait_ready(chip);
> > > +		cond_delay(nfc_op.rdy_delay_ns);
> > > +	}
> >
> > else ?
> If (reading) is nothing but else, but it is looking odd. I will change it.
> >
> > > +	if (reading) {
> > > +		len = nand_subop_get_data_len(subop, op_id);
> > > +		cond_delay(nfc_op.rdy_delay_ns);
> > > +		if (nfc_op.rdy_timeout_ms)
> > > +			nand_wait_ready(chip);
> > > +		pl353_nand_read_data_op(chip, instr->ctx.data.buf.in, len,
> > > +					instr->ctx.data.force_8bit);
> > > +	}
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static const struct nand_op_parser pl353_nfc_op_parser = NAND_OP_PARSER
> > > +	(NAND_OP_PARSER_PATTERN
> > > +		(pl353_nand_exec_op_cmd,
> > > +		NAND_OP_PARSER_PAT_CMD_ELEM(true),
> > > +		NAND_OP_PARSER_PAT_ADDR_ELEM(true, 7),
> > > +		NAND_OP_PARSER_PAT_WAITRDY_ELEM(true),
> > > +		NAND_OP_PARSER_PAT_DATA_IN_ELEM(false, 2048)),
> > > +	NAND_OP_PARSER_PATTERN
> > > +		(pl353_nand_exec_op_cmd,
> > > +		NAND_OP_PARSER_PAT_CMD_ELEM(false),
> > > +		NAND_OP_PARSER_PAT_ADDR_ELEM(false, 7),
> > > +		NAND_OP_PARSER_PAT_CMD_ELEM(false),
> > > +		NAND_OP_PARSER_PAT_WAITRDY_ELEM(false),
> > > +		NAND_OP_PARSER_PAT_DATA_IN_ELEM(false, 2048)),
> > > +	NAND_OP_PARSER_PATTERN
> > > +		(pl353_nand_exec_op_cmd,
> > > +		NAND_OP_PARSER_PAT_CMD_ELEM(false),
> > > +		NAND_OP_PARSER_PAT_ADDR_ELEM(true, 7),
> > > +		NAND_OP_PARSER_PAT_CMD_ELEM(true),
> > > +		NAND_OP_PARSER_PAT_WAITRDY_ELEM(false)),
> > > +	NAND_OP_PARSER_PATTERN
> > > +		(pl353_nand_exec_op_cmd,
> > > +		NAND_OP_PARSER_PAT_CMD_ELEM(false),
> > > +		NAND_OP_PARSER_PAT_ADDR_ELEM(false, 8),
> > > +		NAND_OP_PARSER_PAT_DATA_OUT_ELEM(false, 2048),
> > > +		NAND_OP_PARSER_PAT_CMD_ELEM(true),
> > > +		NAND_OP_PARSER_PAT_WAITRDY_ELEM(true)),
> > > +	NAND_OP_PARSER_PATTERN
> > > +		(pl353_nand_exec_op_cmd,
> > > +		NAND_OP_PARSER_PAT_CMD_ELEM(false)),
> > > +	);
> > > +
> > > +static int pl353_nfc_exec_op(struct nand_chip *chip,
> > > +			     const struct nand_operation *op,
> > > +			     bool check_only)
> > > +{
> > > +	return nand_op_parser_exec_op(chip, &pl353_nfc_op_parser,
> > > +					      op, check_only);
> > > +}
> > > +
> > > +/**
> > > + * pl353_nand_device_ready - Check device ready/busy line
> > > + * @mtd:	Pointer to the mtd_info structure
> > > + *
> > > + * Return:	0 on busy or 1 on ready state
> > > + */
> > > +static int pl353_nand_device_ready(struct nand_chip *chip)
> > > +{
> > > +	if (pl353_smc_get_nand_int_status_raw()) {
> > > +		pl353_smc_clr_nand_int();
> > > +		return 1;
> > > +	}
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +/**
> > > + * pl353_nand_ecc_init - Initialize the ecc information as per the ecc mode
> > > + * @mtd:	Pointer to the mtd_info structure
> > > + * @ecc:	Pointer to ECC control structure
> > > + * @ecc_mode:	ondie ecc status
> > > + *
> > > + * This function initializes the ecc block and functional pointers as per the
> > > + * ecc mode
> > > + *
> > > + * Return:	0 on success or negative errno.
> > > + */
> > > +static int pl353_nand_ecc_init(struct mtd_info *mtd, struct nand_ecc_ctrl *ecc,
> > > +			       int ecc_mode)
> > > +{
> > > +	struct nand_chip *chip = mtd_to_nand(mtd);
> > > +	struct pl353_nand_controller *xnfc =
> > > +		container_of(chip, struct pl353_nand_controller, chip);
> > > +	int err = 0;
> > > +
> > > +	ecc->write_page_raw = pl353_nand_write_page_raw;
> > > +	ecc->read_page_raw = pl353_nand_read_page_raw;
> > > +	ecc->read_oob = pl353_nand_read_oob;
> > > +	ecc->write_oob = pl353_nand_write_oob;
> > > +
> > > +	if (ecc_mode == NAND_ECC_ON_DIE) {
> > > +		pl353_smc_set_ecc_mode(PL353_SMC_ECCMODE_BYPASS);
> > > +		/*
> > > +		 * On-Die ECC spare bytes offset 8 is used for ECC codes
> > > +		 * Use the BBT pattern descriptors
> > > +		 */
> > > +		chip->bbt_td = &bbt_main_descr;
> > > +		chip->bbt_md = &bbt_mirror_descr;
> > > +	} else {
> > > +		ecc->mode = NAND_ECC_HW;
> > > +		/* Hardware ECC generates 3 bytes ECC code for each 512 bytes */
> > > +		ecc->bytes = 3;
> > > +		ecc->strength = 1;
> > > +		ecc->calculate = pl353_nand_calculate_hwecc;
> > > +		ecc->correct = pl353_nand_correct_data;
> > > +		ecc->read_page = pl353_nand_read_page_hwecc;
> > > +		ecc->size = PL353_NAND_ECC_SIZE;
> > > +		ecc->read_page = pl353_nand_read_page_hwecc;
> > > +		ecc->write_page = pl353_nand_write_page_hwecc;
> > > +		pl353_smc_set_ecc_pg_size(mtd->writesize);
> > > +		switch (mtd->writesize) {
> > > +		case SZ_512:
> > > +		case SZ_1K:
> > > +		case SZ_2K:
> > > +			pl353_smc_set_ecc_mode(PL353_SMC_ECCMODE_APB);
> > > +			break;
> > > +		default:
> > > +			ecc->calculate = nand_calculate_ecc;
> > > +			ecc->correct = nand_correct_data;
> > > +			ecc->size = 256;
> > > +			break;
> > > +		}
> > > +
> > > +		if (mtd->oobsize == 16) {
> > > +			mtd_set_ooblayout(mtd, &pl353_ecc_ooblayout16_ops);
> > > +		} else if (mtd->oobsize == 64) {
> > > +			mtd_set_ooblayout(mtd, &pl353_ecc_ooblayout64_ops);
> > > +		} else {
> > > +			err = -ENXIO;
> > > +			dev_err(xnfc->dev, "Unsupported oob Layout\n");
> > > +		}
> > > +	}
> > > +
> > > +	return err;
> > > +}
> > > +
> > > +static int pl353_nfc_setup_data_interface(struct nand_chip *chip, int csline,
> > > +					  const struct nand_data_interface
> > > +					  *conf)
> > > +{
> > > +	struct pl353_nand_controller *xnfc =
> > > +		container_of(chip, struct pl353_nand_controller, chip);
> > > +	const struct nand_sdr_timings *sdr;
> > > +	u32 timings[7], mckperiodps;
> > > +
> > > +	if (csline == NAND_DATA_IFACE_CHECK_ONLY)
> > > +		return 0;
> > > +
> > > +	sdr = nand_get_sdr_timings(conf);
> > > +	if (IS_ERR(sdr))
> > > +		return PTR_ERR(sdr);
> > > +
> > > +	/*
> > > +	 * SDR timings are given in pico-seconds while NFC timings must be
> > > +	 * expressed in NAND controller clock cycles.
> > > +	 */
> > > +	mckperiodps = NSEC_PER_SEC / clk_get_rate(xnfc->mclk);
> > > +	mckperiodps *= 1000;
> > > +	if (sdr->tRC_min <= 20000)
> > > +		/*
> > > +		 * PL353 SMC needs one extra read cycle in SDR Mode 5
> > > +		 * This is not written anywhere in the datasheet but
> > > +		 * the results observed during testing.
> > > +		 */
> > > +		timings[0] = DIV_ROUND_UP(sdr->tRC_min, mckperiodps) + 1;
> > > +	else
> > > +		timings[0] = DIV_ROUND_UP(sdr->tRC_min, mckperiodps);
> > > +
> > > +	timings[1] = DIV_ROUND_UP(sdr->tWC_min, mckperiodps);
> > > +	/*
> > > +	 * For all SDR modes, PL353 SMC needs tREA max value as 1,
> > > +	 * Results observed during testing.
> > > +	 */
> > > +	timings[2] = PL353_TREA_MAX_VALUE;
> > > +	timings[3] = DIV_ROUND_UP(sdr->tWP_min, mckperiodps);
> > > +	timings[4] = DIV_ROUND_UP(sdr->tCLR_min, mckperiodps);
> > > +	timings[5] = DIV_ROUND_UP(sdr->tAR_min, mckperiodps);
> > > +	timings[6] = DIV_ROUND_UP(sdr->tRR_min, mckperiodps);
> > > +	pl353_smc_set_cycles(timings);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static int pl353_nand_attach_chip(struct nand_chip *chip)
> > > +{
> > > +	struct mtd_info *mtd = nand_to_mtd(chip);
> > > +	struct pl353_nand_controller *xnfc =
> > > +		container_of(chip, struct pl353_nand_controller, chip);
> > > +	u32 ret;
> > > +
> > > +	if (chip->options & NAND_BUSWIDTH_16)
> > > +		pl353_smc_set_buswidth(PL353_SMC_MEM_WIDTH_16);
> > > +
> > > +	if (mtd->writesize <= SZ_512)
> > > +		xnfc->addr_cycles = 1;
> > > +	else
> > > +		xnfc->addr_cycles = 2;
> > > +
> > > +	if (chip->options & NAND_ROW_ADDR_3)
> > > +		xnfc->addr_cycles += 3;
> > > +	else
> > > +		xnfc->addr_cycles += 2;
> > > +
> > > +	ret = pl353_nand_ecc_init(mtd, &chip->ecc, chip->ecc.mode);
> > > +	if (ret) {
> > > +		dev_err(xnfc->dev, "ECC init failed\n");
> > > +		return ret;
> > > +	}
> > > +
> > > +	if (!mtd->name) {
> > > +		/*
> > > +		 * If the new bindings are used and the bootloader has not been
> > > +		 * updated to pass a new mtdparts parameter on the cmdline, you
> > > +		 * should define the following property in your NAND node, ie:
> > > +		 *
> > > +		 *	label = "pl353-nand";
> > > +		 *
> > > +		 * This way, mtd->name will be set by the core when
> > > +		 * nand_set_flash_node() is called.
> > > +		 */
> > > +		mtd->name = devm_kasprintf(xnfc->dev, GFP_KERNEL,
> > > +					   "%s", PL353_NAND_DRIVER_NAME);
> > > +		if (!mtd->name) {
> > > +			dev_err(xnfc->dev, "Failed to allocate mtd->name\n");
> > > +			return -ENOMEM;
> > > +		}
> > > +	}
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static const struct nand_controller_ops pl353_nand_controller_ops = {
> > > +	.attach_chip = pl353_nand_attach_chip,
> > > +	.exec_op = pl353_nfc_exec_op,
> > > +	.setup_data_interface = pl353_nfc_setup_data_interface,
> > > +};
> > > +
> > > +/**
> > > + * pl353_nand_probe - Probe method for the NAND driver
> > > + * @pdev:	Pointer to the platform_device structure
> > > + *
> > > + * This function initializes the driver data structures and the hardware.
> > > + * The NAND driver has dependency with the pl353_smc memory controller
> > > + * driver for initializing the NAND timing parameters, bus width, ECC modes,
> > > + * control and status information.
> > > + *
> > > + * Return:	0 on success or error value on failure
> > > + */
> > > +static int pl353_nand_probe(struct platform_device *pdev)
> > > +{
> > > +	struct pl353_nand_controller *xnfc;
> > > +	struct mtd_info *mtd;
> > > +	struct nand_chip *chip;
> > > +	struct resource *res;
> > > +	struct device_node *np, *dn;
> > > +	u32 ret, val;
> > > +
> > > +	xnfc = devm_kzalloc(&pdev->dev, sizeof(*xnfc), GFP_KERNEL);
> > > +	if (!xnfc)
> > > +		return -ENOMEM;
> > > +	xnfc->dev = &pdev->dev;
> > > +
> > > +	nand_controller_init(&xnfc->controller);
> > > +	xnfc->controller.ops = &pl353_nand_controller_ops;
> > > +	/* Map physical address of NAND flash */
> > > +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > > +	xnfc->regs = devm_ioremap_resource(xnfc->dev, res);
> > > +	if (IS_ERR(xnfc->regs))
> > > +		return PTR_ERR(xnfc->regs);
> > > +
> > > +	chip = &xnfc->chip;
> > > +	chip->controller = &xnfc->controller;
> > > +	mtd = nand_to_mtd(chip);
> > > +	nand_set_controller_data(chip, xnfc);
> > > +	mtd->priv = chip;
> > > +	mtd->owner = THIS_MODULE;
> > > +	nand_set_flash_node(chip, xnfc->dev->of_node);
> > > +
> > > +	/* Set the driver entry points for MTD */
> > > +	chip->legacy.dev_ready = pl353_nand_device_ready;
> >
> > Please do not implement legacy interfaces.
> Ok, now it is moved to nand_legacy.c, I will update it.
> 
> Thanks,
> Naga Sureshkumar Relli
> >
> > > +	/* If we don't set this delay driver sets 20us by default */
> > > +	np = of_get_next_parent(xnfc->dev->of_node);
> > > +	xnfc->mclk = of_clk_get(np, 0);
> > > +	if (IS_ERR(xnfc->mclk)) {
> > > +		dev_err(xnfc->dev, "Failed to retrieve MCK clk\n");
> > > +		return PTR_ERR(xnfc->mclk);
> > > +	}
> > > +
> > > +	dn = nand_get_flash_node(chip);
> > > +
> > > +	/* Set the device option and flash width */
> > > +	chip->options = NAND_BUSWIDTH_AUTO;
> > > +	chip->bbt_options = NAND_BBT_USE_FLASH;
> > > +	platform_set_drvdata(pdev, xnfc);
> > > +	ret = nand_scan(chip, 1);
> > > +	if (ret) {
> > > +		dev_err(xnfc->dev, "could not scan the nand chip\n");
> > > +		return ret;
> > > +	}
> > > +
> > > +	ret = mtd_device_register(mtd, NULL, 0);
> > > +	if (ret) {
> > > +		dev_err(xnfc->dev, "Failed to register mtd device: %d\n", ret);
> > > +		nand_cleanup(chip);
> > > +		return ret;
> > > +	}
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +/**
> > > + * pl353_nand_remove - Remove method for the NAND driver
> > > + * @pdev:	Pointer to the platform_device structure
> > > + *
> > > + * This function is called if the driver module is being unloaded. It frees all
> > > + * resources allocated to the device.
> > > + *
> > > + * Return:	0 on success or error value on failure
> > > + */
> > > +static int pl353_nand_remove(struct platform_device *pdev)
> > > +{
> > > +	struct pl353_nand_controller *xnfc = platform_get_drvdata(pdev);
> > > +	struct mtd_info *mtd = nand_to_mtd(&xnfc->chip);
> > > +	struct nand_chip *chip = mtd_to_nand(mtd);
> > > +
> > > +	/* Release resources, unregister device */
> > > +	nand_release(chip);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +/* Match table for device tree binding */
> > > +static const struct of_device_id pl353_nand_of_match[] = {
> > > +	{ .compatible = "arm,pl353-nand-r2p1" },
> > > +	{},
> > > +};
> > > +MODULE_DEVICE_TABLE(of, pl353_nand_of_match);
> > > +
> > > +/*
> > > + * pl353_nand_driver - This structure defines the NAND subsystem platform driver
> > > + */
> > > +static struct platform_driver pl353_nand_driver = {
> > > +	.probe		= pl353_nand_probe,
> > > +	.remove		= pl353_nand_remove,
> > > +	.driver		= {
> > > +		.name	= PL353_NAND_DRIVER_NAME,
> > > +		.of_match_table = pl353_nand_of_match,
> > > +	},
> > > +};
> > > +
> > > +module_platform_driver(pl353_nand_driver);
> > > +
> > > +MODULE_AUTHOR("Xilinx, Inc.");
> > > +MODULE_ALIAS("platform:" PL353_NAND_DRIVER_NAME);
> > > +MODULE_DESCRIPTION("ARM PL353 NAND Flash Driver");
> > > +MODULE_LICENSE("GPL");
> >
> >
> > Thanks,
> > Miquèl
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