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Date:   Fri, 30 Aug 2019 11:46:45 +0200
From:   Miquel Raynal <miquel.raynal@bootlin.com>
To:     Piotr Sroka <piotrs@cadence.com>
Cc:     <linux-kernel@vger.kernel.org>,
        Boris Brezillon <bbrezillon@kernel.org>,
        Richard Weinberger <richard@nod.at>,
        David Woodhouse <dwmw2@infradead.org>,
        Brian Norris <computersforpeace@gmail.com>,
        Marek Vasut <marek.vasut@gmail.com>,
        Paul Burton <paul.burton@mips.com>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Marcel Ziswiler <marcel.ziswiler@toradex.com>,
        Dmitry Osipenko <digetx@gmail.com>,
        Stefan Agner <stefan@agner.ch>,
        <linux-mtd@lists.infradead.org>,
        Kazuhiro Kasai <kasai.kazuhiro@socionext.com>
Subject: Re: [v5 1/2] mtd: nand: Add new Cadence NAND driver to MTD
 subsystem
Message-ID: <20190830114645.59898cfe@xps13>
In-Reply-To: <20190725150012.14416-1-piotrs@cadence.com>
References: <20190725145804.8886-1-piotrs@cadence.com>
        <20190725150012.14416-1-piotrs@cadence.com>
Organization: Bootlin
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Sender: linux-kernel-owner@vger.kernel.org
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Hi Piotr,

Piotr Sroka <piotrs@cadence.com> wrote on Thu, 25 Jul 2019 16:00:12
+0100:

Subject should be: mtd: rawnand:

Last few nits in your driver which overall looks good (see below).

Now I'm waiting for Rob's ack on the bindings. This driver should be a
good candidate for 5.5.

> Add new Cadence NAND driver to MTD subsystem
> 
> Signed-off-by: Piotr Sroka <piotrs@cadence.com>
> ---
> Changes for v5:
> - fix "ecc config strength" field size
> - remove unused macros
> - fix address of timing2 register
> - add guard for accessing data_control_size register
> - simplify the driver by use the same function 
>   for accessing main area and oob area
> - add comment to the driver describing main controller modes
> - change compatible name from cdns,hpnfc to cdns,hp-nfc
> Changes for v4:
> - fix comments issues like typos, missing capitals, missing dots etc.
> - remove unnecessary PHY options phy_dll_aging and phy_per_bit_deskew
> - replace all register access functions to "relaxed" version
> - remove all unnecessary variables initializations
> - handle error inside cadence_nand_get_ecc_strength_idx function in case 
>   correnction strength is not found
> - add commit message
> Changes for v3:
> - remove definitions of unused registers
> - remove configuring registers which are not expected to be configured in
>   asynchronous mode
> - remove not needed function reading timing registers
> - remove information about oob size and write size from cdns_nand_chip type
>   and use vales from mtd_info directly
> - use nand_cleanup instead of nand_release if mtd device is not registered yet
> - fix cadence_nand_chips_init function add garbage collection 
>   if a chip init fails
> - simplify PHY calculations
> Changes for v2:
> - create one universal wait function for all events instead of one
>   function per event.
> - split one big function executing nand operations to separate
>   functions one per each type of operation.
> - add erase atomic operation to nand operation parser
> - remove unnecessary includes.
> - remove unused register defines 
> - add support for multiple nand chips
> - remove all code using legacy functions
> - remove chip dependents parameters from dts bindings, they were
>   attached to the SoC specific compatible at the driver level
> - simplify interrupt handling
> - simplify timing calculations
> - fix calculation of maximum supported cs signals
> - simplify ecc size calculation
> - remove header file and put whole code to one c file
> ---
>  drivers/mtd/nand/raw/Kconfig                   |    7 +
>  drivers/mtd/nand/raw/Makefile                  |    1 +
>  drivers/mtd/nand/raw/cadence-nand-controller.c | 3021 ++++++++++++++++++++++++
>  3 files changed, 3029 insertions(+)
>  create mode 100644 drivers/mtd/nand/raw/cadence-nand-controller.c
> 
> diff --git a/drivers/mtd/nand/raw/Kconfig b/drivers/mtd/nand/raw/Kconfig
> index e604625e2dfa..4d2ce3b5b2ae 100644
> --- a/drivers/mtd/nand/raw/Kconfig
> +++ b/drivers/mtd/nand/raw/Kconfig
> @@ -557,5 +557,12 @@ config MTD_NAND_MESON
>  	help
>  	  Enables support for NAND controller on Amlogic's Meson SoCs.
>  	  This controller is found on Meson SoCs.

Missing space?

> +config MTD_NAND_CADENCE
> +	tristate "Support Cadence NAND (HPNFC) controller"
> +	depends on OF

 || COMPILE_TEST

> +	help
> +	  Enable the driver for NAND flash on platforms using a Cadence NAND
> +	  controller.
> +
>  
>  endif # MTD_NAND
> diff --git a/drivers/mtd/nand/raw/Makefile b/drivers/mtd/nand/raw/Makefile
> index 5a5a72f0793e..f4b099f276f7 100644
> --- a/drivers/mtd/nand/raw/Makefile
> +++ b/drivers/mtd/nand/raw/Makefile
> @@ -58,6 +58,7 @@ obj-$(CONFIG_MTD_NAND_MTK)		+= mtk_ecc.o mtk_nand.o
>  obj-$(CONFIG_MTD_NAND_TEGRA)		+= tegra_nand.o
>  obj-$(CONFIG_MTD_NAND_STM32_FMC2)	+= stm32_fmc2_nand.o
>  obj-$(CONFIG_MTD_NAND_MESON)		+= meson_nand.o
> +obj-$(CONFIG_MTD_NAND_CADENCE)		+= cadence-nand-controller.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/cadence-nand-controller.c b/drivers/mtd/nand/raw/cadence-nand-controller.c
> new file mode 100644
> index 000000000000..a7ff4e4585d3
> --- /dev/null
> +++ b/drivers/mtd/nand/raw/cadence-nand-controller.c
> @@ -0,0 +1,3021 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Cadence NAND flash controller driver
> + *
> + * Copyright (C) 2019 Cadence

I guess you deserve the Author: entry here :)

> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/clk.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/dmaengine.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/mtd/mtd.h>
> +#include <linux/mtd/rawnand.h>
> +#include <linux/of_device.h>
> +#include <linux/iopoll.h>
> +
> +/*
> + * HPNFC can work in 3 modes:
> + * -  PIO - can work in master or slave DMA.
> + * -  CDMA - needs Master DMA for accessing command descriptors.
> + * -  Generic mode - can use only slave DMA.
> + * CDMA and PIO modes can be used to execute only base commands.
> + * Generic mode can be used to execute any command
> + * on NAND flash memory. Driver uses CDMA mode for
> + * block erasing, page reading, page programing.
> + * Generic mode is used for executing rest of commands.
> + */
> +
> +#define MAX_OOB_SIZE_PER_SECTOR	32
> +#define MAX_ADDRESS_CYC		6
> +#define MAX_ERASE_ADDRESS_CYC	3
> +#define MAX_DATA_SIZE		0xFFFC
> +
> +/* Register definition. */
> +/*
> + * Command register 0.
> + * Writing data to this register will initiate a new transaction
> + * of the NF controller.
> + */
> +#define CMD_REG0			0x0000
> +/* Command type field mask. */
> +#define		CMD_REG0_CT		GENMASK(31, 30)
> +/* Command type CDMA. */
> +#define		CMD_REG0_CT_CDMA	0uL
> +/* Command type generic. */
> +#define		CMD_REG0_CT_GEN		3uL
> +/* Command thread number field mask. */
> +#define		CMD_REG0_TN		GENMASK(27, 24)
> +
> +/* Command register 2. */
> +#define CMD_REG2			0x0008
> +/* Command register 3. */
> +#define CMD_REG3			0x000C
> +/* Pointer register to select which thread status will be selected. */
> +#define CMD_STATUS_PTR			0x0010
> +/* Command status register for selected thread. */
> +#define CMD_STATUS			0x0014
> +
> +/* Interrupt status register. */
> +#define INTR_STATUS			0x0110
> +#define		INTR_STATUS_SDMA_ERR	BIT(22)
> +#define		INTR_STATUS_SDMA_TRIGG	BIT(21)
> +#define		INTR_STATUS_UNSUPP_CMD	BIT(19)
> +#define		INTR_STATUS_DDMA_TERR	BIT(18)
> +#define		INTR_STATUS_CDMA_TERR	BIT(17)
> +#define		INTR_STATUS_CDMA_IDL	BIT(16)
> +
> +/* Interrupt enable register. */
> +#define INTR_ENABLE				0x0114
> +#define		INTR_ENABLE_INTR_EN		BIT(31)
> +#define		INTR_ENABLE_SDMA_ERR_EN		BIT(22)
> +#define		INTR_ENABLE_SDMA_TRIGG_EN	BIT(21)
> +#define		INTR_ENABLE_UNSUPP_CMD_EN	BIT(19)
> +#define		INTR_ENABLE_DDMA_TERR_EN	BIT(18)
> +#define		INTR_ENABLE_CDMA_TERR_EN	BIT(17)
> +#define		INTR_ENABLE_CDMA_IDLE_EN	BIT(16)
> +
> +/* Controller internal state. */
> +#define CTRL_STATUS				0x0118
> +#define		CTRL_STATUS_INIT_COMP		BIT(9)
> +#define		CTRL_STATUS_CTRL_BUSY		BIT(8)
> +
> +/* Command Engine threads state. */
> +#define TRD_STATUS				0x0120
> +
> +/* Command Engine interrupt thread error status. */
> +#define TRD_ERR_INT_STATUS			0x0128
> +/* Command Engine interrupt thread error enable. */
> +#define TRD_ERR_INT_STATUS_EN			0x0130
> +/* Command Engine interrupt thread complete status. */
> +#define TRD_COMP_INT_STATUS			0x0138
> +
> +/*
> + * Transfer config 0 register.
> + * Configures data transfer parameters.
> + */
> +#define TRAN_CFG_0				0x0400
> +/* Offset value from the beginning of the page. */
> +#define		TRAN_CFG_0_OFFSET		GENMASK(31, 16)
> +/* Numbers of sectors to transfer within singlNF device's page. */
> +#define		TRAN_CFG_0_SEC_CNT		GENMASK(7, 0)
> +
> +/*
> + * Transfer config 1 register.
> + * Configures data transfer parameters.
> + */
> +#define TRAN_CFG_1				0x0404
> +/* Size of last data sector. */
> +#define		TRAN_CFG_1_LAST_SEC_SIZE	GENMASK(31, 16)
> +/* Size of not-last data sector. */
> +#define		TRAN_CFG_1_SECTOR_SIZE		GENMASK(15, 0)
> +
> +/* ECC engine configuration register 0. */
> +#define ECC_CONFIG_0				0x0428
> +/* Correction strength. */
> +#define		ECC_CONFIG_0_CORR_STR		GENMASK(10, 8)
> +/* Enable erased pages detection mechanism. */
> +#define		ECC_CONFIG_0_ERASE_DET_EN	BIT(1)
> +/* Enable controller ECC check bits generation and correction. */
> +#define		ECC_CONFIG_0_ECC_EN		BIT(0)
> +
> +/* ECC engine configuration register 1. */
> +#define ECC_CONFIG_1				0x042C
> +
> +/* Multiplane settings register. */
> +#define MULTIPLANE_CFG				0x0434
> +/* Cache operation settings. */
> +#define CACHE_CFG				0x0438
> +
> +/* DMA settings register. */
> +#define DMA_SETINGS				0x043C
> +/* Enable SDMA error report on access unprepared slave DMA interface. */
> +#define		DMA_SETINGS_SDMA_ERR_RSP	BIT(17)
> +
> +/* Transferred data block size for the slave DMA module. */
> +#define SDMA_SIZE				0x0440
> +
> +/* Thread number associated with transferred data block
> + * for the slave DMA module.
> + */
> +#define SDMA_TRD_NUM				0x0444
> +/* Thread number mask. */
> +#define		SDMA_TRD_NUM_SDMA_TRD		GENMASK(2, 0)
> +
> +#define CONTROL_DATA_CTRL			0x0494
> +/* Thread number mask. */
> +#define		CONTROL_DATA_CTRL_SIZE		GENMASK(15, 0)
> +
> +#define CTRL_VERSION				0x800
> +
> +/* Available hardware features of the controller. */
> +#define CTRL_FEATURES				0x804
> +/* Support for NV-DDR2/3 work mode. */
> +#define		CTRL_FEATURES_NVDDR_2_3		BIT(28)
> +/* Support for NV-DDR work mode. */
> +#define		CTRL_FEATURES_NVDDR		BIT(27)
> +/* Support for asynchronous work mode. */
> +#define		CTRL_FEATURES_ASYNC		BIT(26)
> +/* Support for asynchronous work mode. */
> +#define		CTRL_FEATURES_N_BANKS		GENMASK(25, 24)
> +/* Slave and Master DMA data width. */
> +#define		CTRL_FEATURES_DMA_DWITH64	BIT(21)
> +/* Availability of Control Data feature.*/
> +#define		CTRL_FEATURES_CONTROL_DATA	BIT(10)
> +
> +/* BCH Engine identification register 0 - correction strengths. */
> +#define BCH_CFG_0				0x838
> +#define		BCH_CFG_0_CORR_CAP_0		GENMASK(7, 0)
> +#define		BCH_CFG_0_CORR_CAP_1		GENMASK(15, 8)
> +#define		BCH_CFG_0_CORR_CAP_2		GENMASK(23, 16)
> +#define		BCH_CFG_0_CORR_CAP_3		GENMASK(31, 24)
> +
> +/* BCH Engine identification register 1 - correction strengths. */
> +#define BCH_CFG_1				0x83C
> +#define		BCH_CFG_1_CORR_CAP_4		GENMASK(7, 0)
> +#define		BCH_CFG_1_CORR_CAP_5		GENMASK(15, 8)
> +#define		BCH_CFG_1_CORR_CAP_6		GENMASK(23, 16)
> +#define		BCH_CFG_1_CORR_CAP_7		GENMASK(31, 24)
> +
> +/* BCH Engine identification register 2 - sector sizes. */
> +#define BCH_CFG_2				0x840
> +#define		BCH_CFG_2_SECT_0		GENMASK(15, 0)
> +#define		BCH_CFG_2_SECT_1		GENMASK(31, 16)
> +
> +/* BCH Engine identification register 3. */
> +#define BCH_CFG_3				0x844
> +
> +/* Ready/Busy# line status. */
> +#define RBN_SETINGS				0x1004
> +
> +/* Common settings. */
> +#define COMMON_SET				0x1008
> +/* 16 bit device connected to the NAND Flash interface. */
> +#define		COMMON_SET_DEVICE_16BIT		BIT(8)
> +
> +/* Skip_bytes registers. */
> +#define SKIP_BYTES_CONF				0x100C
> +#define		SKIP_BYTES_MARKER_VALUE		GENMASK(31, 16)
> +#define		SKIP_BYTES_NUM_OF_BYTES		GENMASK(7, 0)
> +
> +#define SKIP_BYTES_OFFSET			0x1010
> +#define		 SKIP_BYTES_OFFSET_VALUE	GENMASK(23, 0)
> +
> +/* Timings configuration. */
> +#define ASYNC_TOGGLE_TIMINGS			0x101c
> +#define		ASYNC_TOGGLE_TIMINGS_TRH	GENMASK(28, 24)
> +#define		ASYNC_TOGGLE_TIMINGS_TRP	GENMASK(20, 16)
> +#define		ASYNC_TOGGLE_TIMINGS_TWH	GENMASK(12, 8)
> +#define		ASYNC_TOGGLE_TIMINGS_TWP	GENMASK(4, 0)
> +
> +#define	TIMINGS0				0x1024
> +#define		TIMINGS0_TADL			GENMASK(31, 24)
> +#define		TIMINGS0_TCCS			GENMASK(23, 16)
> +#define		TIMINGS0_TWHR			GENMASK(15, 8)
> +#define		TIMINGS0_TRHW			GENMASK(7, 0)
> +
> +#define	TIMINGS1				0x1028
> +#define		TIMINGS1_TRHZ			GENMASK(31, 24)
> +#define		TIMINGS1_TWB			GENMASK(23, 16)
> +#define		TIMINGS1_TVDLY			GENMASK(7, 0)
> +
> +#define	TIMINGS2				0x102c
> +#define		TIMINGS2_TFEAT			GENMASK(25, 16)
> +#define		TIMINGS2_CS_HOLD_TIME		GENMASK(13, 8)
> +#define		TIMINGS2_CS_SETUP_TIME		GENMASK(5, 0)
> +
> +/* Configuration of the resynchronization of slave DLL of PHY. */
> +#define DLL_PHY_CTRL				0x1034
> +#define		DLL_PHY_CTRL_DLL_RST_N		BIT(24)
> +#define		DLL_PHY_CTRL_EXTENDED_WR_MODE	BIT(17)
> +#define		DLL_PHY_CTRL_EXTENDED_RD_MODE	BIT(16)
> +#define		DLL_PHY_CTRL_RS_HIGH_WAIT_CNT	GENMASK(11, 8)
> +#define		DLL_PHY_CTRL_RS_IDLE_CNT	GENMASK(7, 0)
> +
> +/* Register controlling DQ related timing. */
> +#define PHY_DQ_TIMING				0x2000
> +/* Register controlling DSQ related timing.  */
> +#define PHY_DQS_TIMING				0x2004
> +#define		PHY_DQS_TIMING_DQS_SEL_OE_END	GENMASK(3, 0)
> +#define		PHY_DQS_TIMING_PHONY_DQS_SEL	BIT(16)
> +#define		PHY_DQS_TIMING_USE_PHONY_DQS	BIT(20)
> +
> +/* Register controlling the gate and loopback control related timing. */
> +#define PHY_GATE_LPBK_CTRL			0x2008
> +#define		PHY_GATE_LPBK_CTRL_RDS		GENMASK(24, 19)
> +
> +/* Register holds the control for the master DLL logic. */
> +#define PHY_DLL_MASTER_CTRL			0x200C
> +#define		PHY_DLL_MASTER_CTRL_BYPASS_MODE	BIT(23)
> +
> +/* Register holds the control for the slave DLL logic. */
> +#define PHY_DLL_SLAVE_CTRL			0x2010
> +
> +/* This register handles the global control settings for the PHY. */
> +#define PHY_CTRL				0x2080
> +#define		PHY_CTRL_SDR_DQS		BIT(14)
> +#define		PHY_CTRL_PHONY_DQS		GENMASK(9, 4)
> +
> +/*
> + * This register handles the global control settings
> + * for the termination selects for reads.
> + */
> +#define PHY_TSEL				0x2084
> +
> +/* Generic command layout. */
> +#define GCMD_LAY_CS			GENMASK_ULL(11, 8)
> +/*
> + * This bit informs the minicotroller if it has to wait for tWB
> + * after sending the last CMD/ADDR/DATA in the sequence.
> + */
> +#define GCMD_LAY_TWB			BIT_ULL(6)
> +/* Type of generic instruction. */
> +#define GCMD_LAY_INSTR			GENMASK_ULL(5, 0)
> +
> +/* Generic CMD sequence type. */
> +#define		GCMD_LAY_INSTR_CMD	0
> +/* Generic ADDR sequence type. */
> +#define		GCMD_LAY_INSTR_ADDR	1
> +/* Generic data transfer sequence type. */
> +#define		GCMD_LAY_INSTR_DATA	2
> +
> +/* Input part of generic command type of input is command. */
> +#define GCMD_LAY_INPUT_CMD		GENMASK_ULL(23, 16)
> +
> +/* Generic command address sequence - address fields. */
> +#define GCMD_LAY_INPUT_ADDR		GENMASK_ULL(63, 16)
> +/* Generic command address sequence - address size. */
> +#define GCMD_LAY_INPUT_ADDR_SIZE	GENMASK_ULL(13, 11)
> +
> +/* Transfer direction field of generic command data sequence. */
> +#define GCMD_DIR			BIT_ULL(11)
> +/* Read transfer direction of generic command data sequence. */
> +#define		GCMD_DIR_READ		0
> +/* Write transfer direction of generic command data sequence. */
> +#define		GCMD_DIR_WRITE		1
> +
> +/* ECC enabled flag of generic command data sequence - ECC enabled. */
> +#define GCMD_ECC_EN			BIT_ULL(12)
> +/* Generic command data sequence - sector size. */
> +#define GCMD_SECT_SIZE			GENMASK_ULL(31, 16)
> +/* Generic command data sequence - sector count. */
> +#define GCMD_SECT_CNT			GENMASK_ULL(39, 32)
> +/* Generic command data sequence - last sector size. */
> +#define GCMD_LAST_SIZE			GENMASK_ULL(55, 40)
> +
> +/* CDMA descriptor fields. */
> +/* Erase command type of CDMA descriptor. */
> +#define CDMA_CT_ERASE		0x1000
> +/* Program page command type of CDMA descriptor. */
> +#define CDMA_CT_WR		0x2100
> +/* Read page command type of CDMA descriptor. */
> +#define CDMA_CT_RD		0x2200
> +
> +/* Flash pointer memory shift. */
> +#define CDMA_CFPTR_MEM_SHIFT	24
> +/* Flash pointer memory mask. */
> +#define CDMA_CFPTR_MEM		GENMASK(26, 24)
> +
> +/*
> + * Command DMA descriptor flags. If set causes issue interrupt after
> + * the completion of descriptor processing.
> + */
> +#define CDMA_CF_INT		BIT(8)
> +/*
> + * Command DMA descriptor flags - the next descriptor
> + * address field is valid and descriptor processing should continue.
> + */
> +#define CDMA_CF_CONT		BIT(9)
> +/* DMA master flag of command DMA descriptor. */
> +#define CDMA_CF_DMA_MASTER	BIT(10)
> +
> +/* Operation complete status of command descriptor. */
> +#define CDMA_CS_COMP		BIT(15)
> +/* Operation complete status of command descriptor. */
> +/* Command descriptor status - operation fail. */
> +#define CDMA_CS_FAIL		BIT(14)
> +/* Command descriptor status - page erased. */
> +#define CDMA_CS_ERP		BIT(11)
> +/* Command descriptor status - timeout occurred. */
> +#define CDMA_CS_TOUT		BIT(10)
> +/*
> + * Maximum amount of correction applied to one ECC sector.
> + * It is part of command descriptor status.
> + */
> +#define CDMA_CS_MAXERR		GENMASK(9, 2)
> +/* Command descriptor status - uncorrectable ECC error. */
> +#define CDMA_CS_UNCE		BIT(1)
> +/* Command descriptor status - descriptor error. */
> +#define CDMA_CS_ERR		BIT(0)
> +
> +/* Status of operation - OK. */
> +#define STAT_OK			0
> +/* Status of operation - FAIL. */
> +#define STAT_FAIL		2
> +/* Status of operation - uncorrectable ECC error. */
> +#define STAT_ECC_UNCORR		3
> +/* Status of operation - page erased. */
> +#define STAT_ERASED		5
> +/* Status of operation - correctable ECC error. */
> +#define STAT_ECC_CORR		6
> +/* Status of operation - unsuspected state. */
> +#define STAT_UNKNOWN		7
> +/* Status of operation - operation is not completed yet. */
> +#define STAT_BUSY		0xFF
> +
> +#define BCH_MAX_NUM_CORR_CAPS		8
> +#define BCH_MAX_NUM_SECTOR_SIZES	2
> +
> +struct cadence_nand_timings {
> +	u32 async_toggle_timings;
> +	u32 timings0;
> +	u32 timings1;
> +	u32 timings2;
> +	u32 dll_phy_ctrl;
> +	u32 phy_ctrl;
> +	u32 phy_dqs_timing;
> +	u32 phy_gate_lpbk_ctrl;
> +};
> +
> +/* Command DMA descriptor. */
> +struct cadence_nand_cdma_desc {
> +	/* Next descriptor address. */
> +	u64 next_pointer;
> +
> +	/* Flash address is a 32-bit address comprising of BANK and ROW ADDR. */
> +	u32 flash_pointer;
> +	u32 rsvd0;
> +
> +	/* Operation the controller needs to perform. */
> +	u16 command_type;
> +	u16 rsvd1;
> +	/* Flags for operation of this command. */
> +	u16 command_flags;
> +	u16 rsvd2;
> +
> +	/* System/host memory address required for data DMA commands. */
> +	u64 memory_pointer;
> +
> +	/* Status of operation. */
> +	u32 status;
> +	u32 rsvd3;
> +
> +	/* Address pointer to sync buffer location. */
> +	u64 sync_flag_pointer;
> +
> +	/* Controls the buffer sync mechanism. */
> +	u32 sync_arguments;
> +	u32 rsvd4;
> +
> +	/* Control data pointer. */
> +	u64 ctrl_data_ptr;
> +};
> +
> +/* Interrupt status. */
> +struct cadence_nand_irq_status {
> +	/* Thread operation complete status. */
> +	u32 trd_status;
> +	/* Thread operation error. */
> +	u32 trd_error;
> +	/* Controller status. */
> +	u32 status;
> +};
> +
> +/* Cadence NAND flash controller capabilities get from driver data. */
> +struct cadence_nand_dt_devdata {
> +	/* Skew value of the output signals of the NAND Flash interface. */
> +	u32 if_skew;
> +	/* It informs if slave DMA interface is connected to DMA engine. */
> +	unsigned int has_dma:1;
> +};
> +
> +/* Cadence NAND flash controller capabilities read from registers. */
> +struct cdns_nand_caps {
> +	/* Maximum number of banks supported by hardware. */
> +	u8 max_banks;
> +	/* Slave and Master DMA data width in bytes (4 or 8). */
> +	u8 data_dma_width;
> +	/* Control Data feature supported. */
> +	u8 data_control_supp;
> +	/* Is PHY type DLL. */
> +	u8 is_phy_type_dll;
> +};
> +
> +struct cdns_nand_ctrl {
> +	struct device *dev;
> +	struct nand_controller controller;
> +	struct cadence_nand_cdma_desc *cdma_desc;
> +	/* IP capability. */
> +	const struct cadence_nand_dt_devdata *caps1;
> +	struct cdns_nand_caps caps2;
> +	dma_addr_t dma_cdma_desc;
> +	u8 *buf;
> +	u32 buf_size;
> +	u8 curr_corr_str_idx;
> +
> +	/* Register interface. */
> +	void __iomem *reg;
> +
> +	struct {
> +		void __iomem *virt;
> +		dma_addr_t dma;
> +	} io;
> +
> +	int irq;
> +	/* Interrupts that have happened. */
> +	struct cadence_nand_irq_status irq_status;
> +	/* Interrupts we are waiting for. */
> +	struct cadence_nand_irq_status irq_mask;
> +	struct completion complete;
> +	/* Protect irq_mask and irq_status. */
> +	spinlock_t irq_lock;
> +
> +	int ecc_strengths[BCH_MAX_NUM_CORR_CAPS];
> +	struct nand_ecc_step_info ecc_stepinfos[BCH_MAX_NUM_SECTOR_SIZES];
> +	struct nand_ecc_caps ecc_caps;
> +
> +	int curr_trans_type;
> +
> +	struct dma_chan *dmac;
> +
> +	u32 nf_clk_rate;
> +	/*
> +	 * Estimated Board delay. The value includes the total
> +	 * round trip delay for the signals and is used for deciding on values
> +	 * associated with data read capture.
> +	 */
> +	u32 board_delay;
> +
> +	struct nand_chip *selected_chip;
> +
> +	unsigned long assigned_cs;
> +	struct list_head chips;
> +};
> +
> +struct cdns_nand_chip {
> +	struct cadence_nand_timings timings;
> +	struct nand_chip chip;
> +	u8 nsels;
> +	struct list_head node;
> +
> +	/*
> +	 * part of oob area of NAND flash memory page.
> +	 * This part is available for user to read or write.
> +	 */
> +	u32 avail_oob_size;
> +
> +	/* Sector size. There are few sectors per mtd->writesize */
> +	u32 sector_size;
> +	u32 sector_count;
> +
> +	/* Offset of BBM. */
> +	u8 bbm_offs;
> +	/* Number of bytes reserved for BBM. */
> +	u8 bbm_len;
> +	/* ECC strength index. */
> +	u8 corr_str_idx;
> +
> +	u8 cs[];
> +};
> +
> +struct ecc_info {
> +	int (*calc_ecc_bytes)(int step_size, int strength);
> +	int max_step_size;
> +};
> +
> +static inline struct
> +cdns_nand_chip *to_cdns_nand_chip(struct nand_chip *chip)
> +{
> +	return container_of(chip, struct cdns_nand_chip, chip);
> +}
> +
> +static inline struct
> +cdns_nand_ctrl *to_cdns_nand_ctrl(struct nand_controller *controller)
> +{
> +	return container_of(controller, struct cdns_nand_ctrl, controller);
> +}
> +
> +static bool
> +cadence_nand_dma_buf_ok(struct cdns_nand_ctrl *cdns_ctrl, const void *buf,
> +			u32 buf_len)
> +{
> +	u8 data_dma_width = cdns_ctrl->caps2.data_dma_width;
> +
> +	return buf && virt_addr_valid(buf) &&
> +		likely(IS_ALIGNED((uintptr_t)buf, data_dma_width)) &&
> +		likely(IS_ALIGNED(buf_len, data_dma_width));
> +}
> +
> +static int cadence_nand_wait_for_value(struct cdns_nand_ctrl *cdns_ctrl,
> +				       u32 reg_offset, u32 timeout_us,
> +				       u32 mask, bool is_clear)
> +{
> +	u32 val;
> +	int ret;
> +
> +	ret = readl_relaxed_poll_timeout(cdns_ctrl->reg + reg_offset,
> +					 val, !(val & mask) == is_clear,
> +					 10, timeout_us);
> +
> +	if (ret < 0) {
> +		dev_err(cdns_ctrl->dev,
> +			"Timeout while waiting for reg %x with mask %x is clear %d\n",
> +			reg_offset, mask, is_clear);
> +	}
> +
> +	return ret;
> +}
> +
> +static int cadence_nand_set_ecc_enable(struct cdns_nand_ctrl *cdns_ctrl,
> +				       bool enable)
> +{
> +	u32 reg;
> +
> +	if (cadence_nand_wait_for_value(cdns_ctrl, CTRL_STATUS,
> +					1000000,
> +					CTRL_STATUS_CTRL_BUSY, true))
> +		return -ETIMEDOUT;
> +
> +	reg = readl_relaxed(cdns_ctrl->reg + ECC_CONFIG_0);
> +
> +	if (enable)
> +		reg |= ECC_CONFIG_0_ECC_EN;
> +	else
> +		reg &= ~ECC_CONFIG_0_ECC_EN;
> +
> +	writel_relaxed(reg, cdns_ctrl->reg + ECC_CONFIG_0);
> +
> +	return 0;
> +}
> +
> +static void cadence_nand_set_ecc_strength(struct cdns_nand_ctrl *cdns_ctrl,
> +					  u8 corr_str_idx)
> +{
> +	u32 reg;
> +
> +	if (cdns_ctrl->curr_corr_str_idx == corr_str_idx)
> +		return;
> +
> +	reg = readl_relaxed(cdns_ctrl->reg + ECC_CONFIG_0);
> +	reg &= ~ECC_CONFIG_0_CORR_STR;
> +	reg |= FIELD_PREP(ECC_CONFIG_0_CORR_STR, corr_str_idx);
> +	writel_relaxed(reg, cdns_ctrl->reg + ECC_CONFIG_0);
> +
> +	cdns_ctrl->curr_corr_str_idx = corr_str_idx;
> +}
> +
> +static int cadence_nand_get_ecc_strength_idx(struct cdns_nand_ctrl *cdns_ctrl,
> +					     u8 strength)
> +{
> +	int i, corr_str_idx = -1;
> +
> +	for (i = 0; i < BCH_MAX_NUM_CORR_CAPS; i++) {
> +		if (cdns_ctrl->ecc_strengths[i] == strength) {
> +			corr_str_idx = i;
> +			break;
> +		}
> +	}
> +
> +	return corr_str_idx;
> +}
> +
> +static int cadence_nand_set_skip_marker_val(struct cdns_nand_ctrl *cdns_ctrl,
> +					    u16 marker_value)
> +{
> +	u32 reg;
> +
> +	if (cadence_nand_wait_for_value(cdns_ctrl, CTRL_STATUS,
> +					1000000,
> +					CTRL_STATUS_CTRL_BUSY, true))
> +		return -ETIMEDOUT;
> +
> +	reg = readl_relaxed(cdns_ctrl->reg + SKIP_BYTES_CONF);
> +	reg &= ~SKIP_BYTES_MARKER_VALUE;
> +	reg |= FIELD_PREP(SKIP_BYTES_MARKER_VALUE,
> +			  marker_value);
> +
> +	writel_relaxed(reg, cdns_ctrl->reg + SKIP_BYTES_CONF);
> +
> +	return 0;
> +}
> +
> +static int cadence_nand_set_skip_bytes_conf(struct cdns_nand_ctrl *cdns_ctrl,
> +					    u8 num_of_bytes,
> +					    u32 offset_value,
> +					    int enable)
> +{
> +	u32 reg, skip_bytes_offset;
> +
> +	if (cadence_nand_wait_for_value(cdns_ctrl, CTRL_STATUS,
> +					1000000,
> +					CTRL_STATUS_CTRL_BUSY, true))
> +		return -ETIMEDOUT;
> +
> +	if (!enable) {
> +		num_of_bytes = 0;
> +		offset_value = 0;
> +	}
> +
> +	reg = readl_relaxed(cdns_ctrl->reg + SKIP_BYTES_CONF);
> +	reg &= ~SKIP_BYTES_NUM_OF_BYTES;
> +	reg |= FIELD_PREP(SKIP_BYTES_NUM_OF_BYTES,
> +			  num_of_bytes);
> +	skip_bytes_offset = FIELD_PREP(SKIP_BYTES_OFFSET_VALUE,
> +				       offset_value);
> +
> +	writel_relaxed(reg, cdns_ctrl->reg + SKIP_BYTES_CONF);
> +	writel_relaxed(skip_bytes_offset, cdns_ctrl->reg + SKIP_BYTES_OFFSET);
> +
> +	return 0;
> +}
> +
> +/* Functions enables/disables hardware detection of erased data */
> +static void cadence_nand_set_erase_detection(struct cdns_nand_ctrl *cdns_ctrl,
> +					     bool enable,
> +					     u8 bitflips_threshold)
> +{
> +	u32 reg;
> +
> +	reg = readl_relaxed(cdns_ctrl->reg + ECC_CONFIG_0);
> +
> +	if (enable)
> +		reg |= ECC_CONFIG_0_ERASE_DET_EN;
> +	else
> +		reg &= ~ECC_CONFIG_0_ERASE_DET_EN;
> +
> +	writel_relaxed(reg, cdns_ctrl->reg + ECC_CONFIG_0);
> +	writel_relaxed(bitflips_threshold, cdns_ctrl->reg + ECC_CONFIG_1);
> +}
> +
> +static int cadence_nand_set_access_width16(struct cdns_nand_ctrl *cdns_ctrl,
> +					   bool bit_bus16)
> +{
> +	u32 reg;
> +
> +	if (cadence_nand_wait_for_value(cdns_ctrl, CTRL_STATUS,
> +					1000000,
> +					CTRL_STATUS_CTRL_BUSY, true))
> +		return -ETIMEDOUT;
> +
> +	reg = readl_relaxed(cdns_ctrl->reg + COMMON_SET);
> +
> +	if (!bit_bus16)
> +		reg &= ~COMMON_SET_DEVICE_16BIT;
> +	else
> +		reg |= COMMON_SET_DEVICE_16BIT;
> +	writel_relaxed(reg, cdns_ctrl->reg + COMMON_SET);
> +
> +	return 0;
> +}
> +
> +static void
> +cadence_nand_clear_interrupt(struct cdns_nand_ctrl *cdns_ctrl,
> +			     struct cadence_nand_irq_status *irq_status)
> +{
> +	writel_relaxed(irq_status->status, cdns_ctrl->reg + INTR_STATUS);
> +	writel_relaxed(irq_status->trd_status,
> +		       cdns_ctrl->reg + TRD_COMP_INT_STATUS);
> +	writel_relaxed(irq_status->trd_error,
> +		       cdns_ctrl->reg + TRD_ERR_INT_STATUS);
> +}
> +
> +static void
> +cadence_nand_read_int_status(struct cdns_nand_ctrl *cdns_ctrl,
> +			     struct cadence_nand_irq_status *irq_status)
> +{
> +	irq_status->status = readl_relaxed(cdns_ctrl->reg + INTR_STATUS);
> +	irq_status->trd_status = readl_relaxed(cdns_ctrl->reg
> +					       + TRD_COMP_INT_STATUS);
> +	irq_status->trd_error = readl_relaxed(cdns_ctrl->reg
> +					      + TRD_ERR_INT_STATUS);
> +}
> +
> +static u32 irq_detected(struct cdns_nand_ctrl *cdns_ctrl,
> +			struct cadence_nand_irq_status *irq_status)
> +{
> +	cadence_nand_read_int_status(cdns_ctrl, irq_status);
> +
> +	return irq_status->status || irq_status->trd_status ||
> +		irq_status->trd_error;
> +}
> +
> +static void cadence_nand_reset_irq(struct cdns_nand_ctrl *cdns_ctrl)
> +{
> +	spin_lock(&cdns_ctrl->irq_lock);
> +	memset(&cdns_ctrl->irq_status, 0, sizeof(cdns_ctrl->irq_status));
> +	memset(&cdns_ctrl->irq_mask, 0, sizeof(cdns_ctrl->irq_mask));
> +	spin_unlock(&cdns_ctrl->irq_lock);
> +}
> +
> +/*
> + * This is the interrupt service routine. It handles all interrupts
> + * sent to this device.
> + */
> +static irqreturn_t cadence_nand_isr(int irq, void *dev_id)
> +{
> +	struct cdns_nand_ctrl *cdns_ctrl = dev_id;
> +	struct cadence_nand_irq_status irq_status;
> +	irqreturn_t result = IRQ_NONE;
> +
> +	spin_lock(&cdns_ctrl->irq_lock);
> +
> +	if (irq_detected(cdns_ctrl, &irq_status)) {
> +		/* Handle interrupt. */
> +		/* First acknowledge it. */
> +		cadence_nand_clear_interrupt(cdns_ctrl, &irq_status);
> +		/* Status in the device context for someone to read. */
> +		cdns_ctrl->irq_status.status |= irq_status.status;
> +		cdns_ctrl->irq_status.trd_status |= irq_status.trd_status;
> +		cdns_ctrl->irq_status.trd_error |= irq_status.trd_error;
> +		/* Notify anyone who cares that it happened. */
> +		complete(&cdns_ctrl->complete);
> +		/* Tell the OS that we've handled this. */
> +		result = IRQ_HANDLED;
> +	}
> +	spin_unlock(&cdns_ctrl->irq_lock);

Your locking scheme seems wrong (maybe I'm not going deep enough in the
code), can you please try with LOCKDEP enabled?

> +
> +	return result;
> +}
> +
> +static void cadence_nand_set_irq_mask(struct cdns_nand_ctrl *cdns_ctrl,
> +				      struct cadence_nand_irq_status *irq_mask)
> +{
> +	writel_relaxed(INTR_ENABLE_INTR_EN | irq_mask->status,
> +		       cdns_ctrl->reg + INTR_ENABLE);
> +
> +	writel_relaxed(irq_mask->trd_error,
> +		       cdns_ctrl->reg + TRD_ERR_INT_STATUS_EN);
> +}
> +
> +static void
> +cadence_nand_wait_for_irq(struct cdns_nand_ctrl *cdns_ctrl,
> +			  struct cadence_nand_irq_status *irq_mask,
> +			  struct cadence_nand_irq_status *irq_status)
> +{
> +	unsigned long timeout = msecs_to_jiffies(10000);
> +	unsigned long time_left;
> +
> +	time_left = wait_for_completion_timeout(&cdns_ctrl->complete,
> +						timeout);
> +
> +	*irq_status = cdns_ctrl->irq_status;
> +	if (time_left == 0) {
> +		/* Timeout error. */
> +		dev_err(cdns_ctrl->dev, "timeout occurred:\n");
> +		dev_err(cdns_ctrl->dev, "\tstatus = 0x%x, mask = 0x%x\n",
> +			irq_status->status, irq_mask->status);
> +		dev_err(cdns_ctrl->dev,
> +			"\ttrd_status = 0x%x, trd_status mask = 0x%x\n",
> +			irq_status->trd_status, irq_mask->trd_status);
> +		dev_err(cdns_ctrl->dev,
> +			"\t trd_error = 0x%x, trd_error mask = 0x%x\n",
> +			irq_status->trd_error, irq_mask->trd_error);
> +	}
> +}
> +
> +static void
> +cadence_nand_irq_cleanup(int irqnum, struct cdns_nand_ctrl *cdns_ctrl)
> +{
> +	/* Disable interrupts. */
> +	writel_relaxed(INTR_ENABLE_INTR_EN, cdns_ctrl->reg + INTR_ENABLE);
> +}

Would you mind moving this helper to the bottom, where it is used
(closer to the remove/cleanup functions).

> +
> +/* Execute generic command on NAND controller. */
> +static int cadence_nand_generic_cmd_send(struct cdns_nand_ctrl *cdns_ctrl,
> +					 u8 chip_nr,
> +					 u64 mini_ctrl_cmd)
> +{
> +	u32 mini_ctrl_cmd_l, mini_ctrl_cmd_h, reg;
> +
> +	mini_ctrl_cmd |= FIELD_PREP(GCMD_LAY_CS, chip_nr);
> +	mini_ctrl_cmd_l = mini_ctrl_cmd & 0xFFFFFFFF;
> +	mini_ctrl_cmd_h = mini_ctrl_cmd >> 32;
> +
> +	if (cadence_nand_wait_for_value(cdns_ctrl, CTRL_STATUS,
> +					1000000,
> +					CTRL_STATUS_CTRL_BUSY, true))
> +		return -ETIMEDOUT;
> +
> +	cadence_nand_reset_irq(cdns_ctrl);
> +
> +	writel_relaxed(mini_ctrl_cmd_l, cdns_ctrl->reg + CMD_REG2);
> +	writel_relaxed(mini_ctrl_cmd_h, cdns_ctrl->reg + CMD_REG3);
> +
> +	/* Select generic command. */
> +	reg = FIELD_PREP(CMD_REG0_CT, CMD_REG0_CT_GEN);
> +	/* Thread number. */
> +	reg |= FIELD_PREP(CMD_REG0_TN, 0);
> +
> +	/* Issue command. */
> +	writel_relaxed(reg, cdns_ctrl->reg + CMD_REG0);
> +
> +	return 0;
> +}
> +
> +/* Wait for data on slave DMA interface. */
> +static int cadence_nand_wait_on_sdma(struct cdns_nand_ctrl *cdns_ctrl,
> +				     u8 *out_sdma_trd,
> +				     u32 *out_sdma_size)
> +{
> +	struct cadence_nand_irq_status irq_mask, irq_status;
> +
> +	irq_mask.trd_status = 0;
> +	irq_mask.trd_error = 0;
> +	irq_mask.status = INTR_STATUS_SDMA_TRIGG
> +		| INTR_STATUS_SDMA_ERR
> +		| INTR_STATUS_UNSUPP_CMD;
> +
> +	cadence_nand_set_irq_mask(cdns_ctrl, &irq_mask);
> +	cadence_nand_wait_for_irq(cdns_ctrl, &irq_mask, &irq_status);
> +	if (irq_status.status == 0) {
> +		dev_err(cdns_ctrl->dev, "Timeout while waiting for SDMA\n");
> +		return -ETIMEDOUT;
> +	}
> +
> +	if (irq_status.status & INTR_STATUS_SDMA_TRIGG) {
> +		*out_sdma_size = readl_relaxed(cdns_ctrl->reg + SDMA_SIZE);
> +		*out_sdma_trd  = readl_relaxed(cdns_ctrl->reg + SDMA_TRD_NUM);
> +		*out_sdma_trd =
> +			FIELD_GET(SDMA_TRD_NUM_SDMA_TRD, *out_sdma_trd);
> +	} else {
> +		dev_err(cdns_ctrl->dev, "SDMA error - irq_status %x\n",
> +			irq_status.status);
> +		return -EIO;
> +	}
> +
> +	return 0;
> +}
> +
> +static void cadence_nand_get_caps(struct cdns_nand_ctrl *cdns_ctrl)
> +{
> +	u32  reg;
> +
> +	reg = readl_relaxed(cdns_ctrl->reg + CTRL_FEATURES);
> +
> +	cdns_ctrl->caps2.max_banks = 1 << FIELD_GET(CTRL_FEATURES_N_BANKS, reg);
> +
> +	if (FIELD_GET(CTRL_FEATURES_DMA_DWITH64, reg))
> +		cdns_ctrl->caps2.data_dma_width = 8;
> +	else
> +		cdns_ctrl->caps2.data_dma_width = 4;
> +
> +	if (reg & CTRL_FEATURES_CONTROL_DATA)
> +		cdns_ctrl->caps2.data_control_supp = 1;
> +
> +	if (reg & (CTRL_FEATURES_NVDDR_2_3
> +		   | CTRL_FEATURES_NVDDR))
> +		cdns_ctrl->caps2.is_phy_type_dll = 1;
> +}
> +
> +/* Prepare CDMA descriptor. */
> +static void
> +cadence_nand_cdma_desc_prepare(struct cadence_nand_cdma_desc *cdma_desc,
> +			       char nf_mem, u32 flash_ptr, char *mem_ptr,
> +			       char *ctrl_data_ptr, u16 ctype)
> +{
> +	memset(cdma_desc, 0, sizeof(struct cadence_nand_cdma_desc));
> +
> +	/* Set fields for one descriptor. */
> +	cdma_desc->flash_pointer = (nf_mem << CDMA_CFPTR_MEM_SHIFT)
> +		+ flash_ptr;
> +	cdma_desc->command_flags |= CDMA_CF_DMA_MASTER;
> +	cdma_desc->command_flags  |= CDMA_CF_INT;
> +
> +	cdma_desc->memory_pointer = (uintptr_t)mem_ptr;
> +	cdma_desc->status = 0;
> +	cdma_desc->sync_flag_pointer = 0;
> +	cdma_desc->sync_arguments = 0;
> +
> +	cdma_desc->command_type = ctype;
> +	cdma_desc->ctrl_data_ptr = (uintptr_t)ctrl_data_ptr;
> +}
> +
> +static u8 cadence_nand_check_desc_error(struct cdns_nand_ctrl *cdns_ctrl,
> +					u32 desc_status)
> +{
> +	if (desc_status & CDMA_CS_ERP)
> +		return STAT_ERASED;
> +
> +	if (desc_status & CDMA_CS_UNCE)
> +		return STAT_ECC_UNCORR;
> +
> +	if (desc_status & CDMA_CS_ERR) {
> +		dev_err(cdns_ctrl->dev, ":CDMA desc error flag detected.\n");
> +		return STAT_FAIL;
> +	}
> +
> +	if (FIELD_GET(CDMA_CS_MAXERR, desc_status))
> +		return STAT_ECC_CORR;
> +
> +	return STAT_FAIL;
> +}
> +
> +static int cadence_nand_cdma_finish(struct cdns_nand_ctrl *cdns_ctrl,
> +				    struct cadence_nand_cdma_desc *cdma_desc)
> +{
> +	struct cadence_nand_cdma_desc *desc_ptr = cdma_desc;
> +	u8 status = STAT_BUSY;
> +
> +	if (desc_ptr->status & CDMA_CS_FAIL) {
> +		status = cadence_nand_check_desc_error(cdns_ctrl,
> +						       desc_ptr->status);
> +		dev_err(cdns_ctrl->dev, ":CDMA error %x\n", desc_ptr->status);
> +	} else if (desc_ptr->status & CDMA_CS_COMP) {
> +		/* Descriptor finished with no errors. */
> +		if (desc_ptr->command_flags & CDMA_CF_CONT) {
> +			dev_info(cdns_ctrl->dev, "DMA unsupported flag is set");
> +			status = STAT_UNKNOWN;
> +		} else {
> +			/* Last descriptor.  */
> +			status = STAT_OK;
> +		}
> +	}
> +
> +	return status;
> +}
> +
> +static int cadence_nand_cdma_send(struct cdns_nand_ctrl *cdns_ctrl,
> +				  u8 thread)
> +{
> +	u32 reg;
> +	int status;
> +
> +	/* Wait for thread ready. */
> +	status = cadence_nand_wait_for_value(cdns_ctrl, TRD_STATUS,
> +					     1000000,
> +					     1U << thread, true);
> +	if (status)
> +		return status;
> +
> +	cadence_nand_reset_irq(cdns_ctrl);
> +
> +	writel_relaxed((u32)cdns_ctrl->dma_cdma_desc,
> +		       cdns_ctrl->reg + CMD_REG2);
> +	writel_relaxed(0, cdns_ctrl->reg + CMD_REG3);
> +
> +	/* Select CDMA mode. */
> +	reg = FIELD_PREP(CMD_REG0_CT, CMD_REG0_CT_CDMA);
> +	/* Thread number. */
> +	reg |= FIELD_PREP(CMD_REG0_TN, thread);
> +	/* Issue command. */
> +	writel_relaxed(reg, cdns_ctrl->reg + CMD_REG0);
> +
> +	return 0;
> +}
> +
> +/* Send SDMA command and wait for finish. */
> +static u32
> +cadence_nand_cdma_send_and_wait(struct cdns_nand_ctrl *cdns_ctrl,
> +				u8 thread)
> +{
> +	struct cadence_nand_irq_status irq_mask, irq_status = {0};
> +	int status;
> +
> +	irq_mask.trd_status = 1 << thread;
> +	irq_mask.trd_error = 1 << thread;
> +	irq_mask.status = INTR_STATUS_CDMA_TERR;
> +
> +	cadence_nand_set_irq_mask(cdns_ctrl, &irq_mask);
> +
> +	status = cadence_nand_cdma_send(cdns_ctrl, thread);
> +	if (status)
> +		return status;
> +
> +	cadence_nand_wait_for_irq(cdns_ctrl, &irq_mask, &irq_status);
> +
> +	if (irq_status.status == 0 && irq_status.trd_status == 0 &&
> +	    irq_status.trd_error == 0) {
> +		dev_err(cdns_ctrl->dev, "CDMA command timeout\n");
> +		return -ETIMEDOUT;
> +	}
> +	if (irq_status.status & irq_mask.status) {
> +		dev_err(cdns_ctrl->dev, "CDMA command failed\n");
> +		return -EIO;
> +	}
> +
> +	return 0;
> +}
> +
> +/*
> + * ECC size depends on configured ECC strength and on maximum supported
> + * ECC step size.
> + */
> +static int cadence_nand_calc_ecc_bytes(int max_step_size, int strength)
> +{
> +	int nbytes = DIV_ROUND_UP(fls(8 * max_step_size) * strength, 8);
> +
> +	return ALIGN(nbytes, 2);
> +}
> +
> +#define CADENCE_NAND_CALC_ECC_BYTES(max_step_size) \
> +	static int \
> +	cadence_nand_calc_ecc_bytes_##max_step_size(int step_size, \
> +						    int strength)\
> +	{\
> +		return cadence_nand_calc_ecc_bytes(max_step_size, strength);\
> +	}
> +
> +CADENCE_NAND_CALC_ECC_BYTES(256)
> +CADENCE_NAND_CALC_ECC_BYTES(512)
> +CADENCE_NAND_CALC_ECC_BYTES(1024)
> +CADENCE_NAND_CALC_ECC_BYTES(2048)
> +CADENCE_NAND_CALC_ECC_BYTES(4096)
> +
> +/* Function reads BCH capabilities. */
> +static int cadence_nand_read_bch_caps(struct cdns_nand_ctrl *cdns_ctrl)
> +{
> +	struct nand_ecc_caps *ecc_caps = &cdns_ctrl->ecc_caps;
> +	int max_step_size = 0, nstrengths, i;
> +	u32 reg;
> +
> +	reg = readl_relaxed(cdns_ctrl->reg + BCH_CFG_0);
> +	cdns_ctrl->ecc_strengths[0] = FIELD_GET(BCH_CFG_0_CORR_CAP_0, reg);
> +	cdns_ctrl->ecc_strengths[1] = FIELD_GET(BCH_CFG_0_CORR_CAP_1, reg);
> +	cdns_ctrl->ecc_strengths[2] = FIELD_GET(BCH_CFG_0_CORR_CAP_2, reg);
> +	cdns_ctrl->ecc_strengths[3] = FIELD_GET(BCH_CFG_0_CORR_CAP_3, reg);
> +
> +	reg = readl_relaxed(cdns_ctrl->reg + BCH_CFG_1);
> +	cdns_ctrl->ecc_strengths[4] = FIELD_GET(BCH_CFG_1_CORR_CAP_4, reg);
> +	cdns_ctrl->ecc_strengths[5] = FIELD_GET(BCH_CFG_1_CORR_CAP_5, reg);
> +	cdns_ctrl->ecc_strengths[6] = FIELD_GET(BCH_CFG_1_CORR_CAP_6, reg);
> +	cdns_ctrl->ecc_strengths[7] = FIELD_GET(BCH_CFG_1_CORR_CAP_7, reg);
> +
> +	reg = readl_relaxed(cdns_ctrl->reg + BCH_CFG_2);
> +	cdns_ctrl->ecc_stepinfos[0].stepsize =
> +		FIELD_GET(BCH_CFG_2_SECT_0, reg);
> +
> +	cdns_ctrl->ecc_stepinfos[1].stepsize =
> +		FIELD_GET(BCH_CFG_2_SECT_1, reg);
> +
> +	nstrengths = 0;
> +	for (i = 0; i < BCH_MAX_NUM_CORR_CAPS; i++) {
> +		if (cdns_ctrl->ecc_strengths[i] != 0)
> +			nstrengths++;
> +	}
> +
> +	ecc_caps->nstepinfos = 0;
> +	for (i = 0; i < BCH_MAX_NUM_SECTOR_SIZES; i++) {
> +		/* ECC strengths are common for all step infos. */
> +		cdns_ctrl->ecc_stepinfos[i].nstrengths = nstrengths;
> +		cdns_ctrl->ecc_stepinfos[i].strengths =
> +			cdns_ctrl->ecc_strengths;
> +
> +		if (cdns_ctrl->ecc_stepinfos[i].stepsize != 0)
> +			ecc_caps->nstepinfos++;
> +
> +		if (cdns_ctrl->ecc_stepinfos[i].stepsize > max_step_size)
> +			max_step_size = cdns_ctrl->ecc_stepinfos[i].stepsize;
> +	}
> +	ecc_caps->stepinfos = &cdns_ctrl->ecc_stepinfos[0];
> +
> +	switch (max_step_size) {
> +	case 256:
> +		ecc_caps->calc_ecc_bytes = &cadence_nand_calc_ecc_bytes_256;
> +		break;
> +	case 512:
> +		ecc_caps->calc_ecc_bytes = &cadence_nand_calc_ecc_bytes_512;
> +		break;
> +	case 1024:
> +		ecc_caps->calc_ecc_bytes = &cadence_nand_calc_ecc_bytes_1024;
> +		break;
> +	case 2048:
> +		ecc_caps->calc_ecc_bytes = &cadence_nand_calc_ecc_bytes_2048;
> +		break;
> +	case 4096:
> +		ecc_caps->calc_ecc_bytes = &cadence_nand_calc_ecc_bytes_4096;
> +		break;
> +	default:
> +		dev_err(cdns_ctrl->dev,
> +			"Unsupported sector size(ecc step size) %d\n",
> +			max_step_size);
> +		return -EIO;
> +	}
> +
> +	return 0;
> +}
> +
> +/* Hardware initialization. */
> +static int cadence_nand_hw_init(struct cdns_nand_ctrl *cdns_ctrl)
> +{
> +	int status;
> +	u32 reg;
> +
> +	status = cadence_nand_wait_for_value(cdns_ctrl, CTRL_STATUS,
> +					     1000000,
> +					     CTRL_STATUS_INIT_COMP, false);
> +	if (status)
> +		return status;
> +
> +	reg = readl_relaxed(cdns_ctrl->reg + CTRL_VERSION);
> +
> +	dev_info(cdns_ctrl->dev,
> +		 "%s: cadence nand controller version reg %x\n",
> +		 __func__, reg);
> +
> +	/* Disable cache and multiplane. */
> +	writel_relaxed(0, cdns_ctrl->reg + MULTIPLANE_CFG);
> +	writel_relaxed(0, cdns_ctrl->reg + CACHE_CFG);

Cache?

> +
> +	/* Clear all interrupts. */
> +	writel_relaxed(0xFFFFFFFF, cdns_ctrl->reg + INTR_STATUS);
> +
> +	cadence_nand_get_caps(cdns_ctrl);
> +	cadence_nand_read_bch_caps(cdns_ctrl);
> +
> +	/*
> +	 * Set IO width access to 8.
> +	 * It is because during SW device discovering width access
> +	 * is expected to be 8.
> +	 */
> +	status = cadence_nand_set_access_width16(cdns_ctrl, false);
> +
> +	return status;
> +}
> +
> +#define TT_MAIN_OOB_AREAS	2
> +#define TT_RAW_PAGE		3
> +#define TT_BBM			4
> +#define TT_MAIN_OOB_AREA_EXT	5
> +
> +/* Prepare size of data to transfer. */
> +static void
> +cadence_nand_prepare_data_size(struct nand_chip *chip,
> +			       int transfer_type)
> +{
> +	struct cdns_nand_ctrl *cdns_ctrl = to_cdns_nand_ctrl(chip->controller);
> +	struct cdns_nand_chip *cdns_chip = to_cdns_nand_chip(chip);
> +	struct mtd_info *mtd = nand_to_mtd(chip);
> +	u32 sec_size = 0, offset = 0, sec_cnt = 1;
> +	u32 last_sec_size = cdns_chip->sector_size;
> +	u32 ecc_size = chip->ecc.bytes;
> +	u32 data_ctrl_size = 0;
> +	u32 reg = 0;
> +
> +	if (cdns_ctrl->curr_trans_type == transfer_type)
> +		return;
> +
> +	switch (transfer_type) {
> +	case TT_MAIN_OOB_AREA_EXT:
> +		sec_cnt = cdns_chip->sector_count;
> +		sec_size = cdns_chip->sector_size;
> +		data_ctrl_size = cdns_chip->avail_oob_size;
> +		break;
> +	case TT_MAIN_OOB_AREAS:
> +		sec_cnt = cdns_chip->sector_count;
> +		last_sec_size = cdns_chip->sector_size
> +			+ cdns_chip->avail_oob_size;
> +		sec_size = cdns_chip->sector_size;
> +		break;
> +	case TT_RAW_PAGE:
> +		last_sec_size = mtd->writesize + mtd->oobsize;
> +		break;
> +	case TT_BBM:
> +		offset = mtd->writesize + cdns_chip->bbm_offs;
> +		last_sec_size = 8;
> +		break;
> +	}
> +
> +	reg = 0;
> +	reg |= FIELD_PREP(TRAN_CFG_0_OFFSET, offset);
> +	reg |= FIELD_PREP(TRAN_CFG_0_SEC_CNT, sec_cnt);
> +	writel_relaxed(reg, cdns_ctrl->reg + TRAN_CFG_0);
> +
> +	reg = 0;
> +	reg |= FIELD_PREP(TRAN_CFG_1_LAST_SEC_SIZE, last_sec_size);
> +	reg |= FIELD_PREP(TRAN_CFG_1_SECTOR_SIZE, sec_size);
> +	writel_relaxed(reg, cdns_ctrl->reg + TRAN_CFG_1);
> +
> +	if (cdns_ctrl->caps2.data_control_supp == 1) {
> +		reg = readl_relaxed(cdns_ctrl->reg + CONTROL_DATA_CTRL);
> +		reg &= ~CONTROL_DATA_CTRL_SIZE;
> +		reg |= FIELD_PREP(CONTROL_DATA_CTRL_SIZE, data_ctrl_size);
> +		writel_relaxed(reg, cdns_ctrl->reg + CONTROL_DATA_CTRL);
> +	}
> +
> +	cdns_ctrl->curr_trans_type = transfer_type;
> +}
> +
> +static int
> +cadence_nand_cdma_transfer(struct cdns_nand_ctrl *cdns_ctrl, u8 chip_nr,
> +			   int page, void *buf, void *ctrl_dat, u32 buf_size,
> +			   u32 ctrl_dat_size, enum dma_data_direction dir,
> +			   bool with_ecc)
> +{
> +	struct cadence_nand_cdma_desc *cdma_desc = cdns_ctrl->cdma_desc;
> +	dma_addr_t dma_buf, dma_ctrl_dat = 0;
> +	u8 thread_nr = chip_nr;
> +	int status;
> +	u16 ctype;
> +
> +	if (dir == DMA_FROM_DEVICE)
> +		ctype = CDMA_CT_RD;
> +	else
> +		ctype = CDMA_CT_WR;
> +
> +	cadence_nand_set_ecc_enable(cdns_ctrl, with_ecc);
> +
> +	dma_buf = dma_map_single(cdns_ctrl->dev, buf, buf_size, dir);
> +	if (dma_mapping_error(cdns_ctrl->dev, dma_buf)) {
> +		dev_err(cdns_ctrl->dev, "Failed to map DMA buffer\n");
> +		return -EIO;
> +	}
> +
> +	if (ctrl_dat && ctrl_dat_size) {
> +		dma_ctrl_dat = dma_map_single(cdns_ctrl->dev, ctrl_dat,
> +					      ctrl_dat_size, dir);
> +		if (dma_mapping_error(cdns_ctrl->dev, dma_ctrl_dat)) {
> +			dma_unmap_single(cdns_ctrl->dev, dma_buf,
> +					 buf_size, dir);
> +			dev_err(cdns_ctrl->dev, "Failed to map DMA buffer\n");
> +			return -EIO;
> +		}
> +	}
> +
> +	cadence_nand_cdma_desc_prepare(cdma_desc, chip_nr, page,
> +				       (void *)dma_buf, (void *)dma_ctrl_dat,
> +				       ctype);
> +
> +	status = cadence_nand_cdma_send_and_wait(cdns_ctrl, thread_nr);
> +
> +	dma_unmap_single(cdns_ctrl->dev, dma_buf,
> +			 buf_size, dir);
> +
> +	if (ctrl_dat && ctrl_dat_size)
> +		dma_unmap_single(cdns_ctrl->dev, dma_ctrl_dat,
> +				 ctrl_dat_size, dir);
> +	if (status)
> +		return status;
> +
> +	return cadence_nand_cdma_finish(cdns_ctrl, cdns_ctrl->cdma_desc);
> +}
> +
> +static void cadence_nand_set_timings(struct cdns_nand_ctrl *cdns_ctrl,
> +				     struct cadence_nand_timings *t)
> +{
> +	writel_relaxed(t->async_toggle_timings,
> +		       cdns_ctrl->reg + ASYNC_TOGGLE_TIMINGS);
> +	writel_relaxed(t->timings0, cdns_ctrl->reg + TIMINGS0);
> +	writel_relaxed(t->timings1, cdns_ctrl->reg + TIMINGS1);
> +	writel_relaxed(t->timings2, cdns_ctrl->reg + TIMINGS2);
> +
> +	if (cdns_ctrl->caps2.is_phy_type_dll)
> +		writel_relaxed(t->dll_phy_ctrl, cdns_ctrl->reg + DLL_PHY_CTRL);
> +
> +	writel_relaxed(t->phy_ctrl, cdns_ctrl->reg + PHY_CTRL);
> +
> +	if (cdns_ctrl->caps2.is_phy_type_dll) {
> +		writel_relaxed(0, cdns_ctrl->reg + PHY_TSEL);
> +		writel_relaxed(2, cdns_ctrl->reg + PHY_DQ_TIMING);
> +		writel_relaxed(t->phy_dqs_timing,
> +			       cdns_ctrl->reg + PHY_DQS_TIMING);
> +		writel_relaxed(t->phy_gate_lpbk_ctrl,
> +			       cdns_ctrl->reg + PHY_GATE_LPBK_CTRL);
> +		writel_relaxed(PHY_DLL_MASTER_CTRL_BYPASS_MODE,
> +			       cdns_ctrl->reg + PHY_DLL_MASTER_CTRL);
> +		writel_relaxed(0, cdns_ctrl->reg + PHY_DLL_SLAVE_CTRL);
> +	}
> +}
> +
> +static int cadence_nand_select_target(struct nand_chip *chip)
> +{
> +	struct cdns_nand_ctrl *cdns_ctrl = to_cdns_nand_ctrl(chip->controller);
> +	struct cdns_nand_chip *cdns_chip = to_cdns_nand_chip(chip);
> +
> +	if (chip == cdns_ctrl->selected_chip)
> +		return 0;
> +
> +	if (cadence_nand_wait_for_value(cdns_ctrl, CTRL_STATUS,
> +					1000000,
> +					CTRL_STATUS_CTRL_BUSY, true))
> +		return -ETIMEDOUT;
> +
> +	cadence_nand_set_timings(cdns_ctrl, &cdns_chip->timings);
> +
> +	cadence_nand_set_ecc_strength(cdns_ctrl,
> +				      cdns_chip->corr_str_idx);
> +
> +	cadence_nand_set_erase_detection(cdns_ctrl, true,
> +					 chip->ecc.strength);
> +
> +	cdns_ctrl->curr_trans_type = -1;
> +	cdns_ctrl->selected_chip = chip;
> +
> +	return 0;
> +}
> +
> +static int cadence_nand_erase(struct nand_chip *chip, u32 page)
> +{
> +	struct cdns_nand_ctrl *cdns_ctrl = to_cdns_nand_ctrl(chip->controller);
> +	struct cdns_nand_chip *cdns_chip = to_cdns_nand_chip(chip);
> +	int status;
> +	u8 thread_nr = cdns_chip->cs[chip->cur_cs];
> +
> +	cadence_nand_cdma_desc_prepare(cdns_ctrl->cdma_desc,
> +				       cdns_chip->cs[chip->cur_cs],
> +				       page, NULL, NULL,
> +				       CDMA_CT_ERASE);
> +	status = cadence_nand_cdma_send_and_wait(cdns_ctrl, thread_nr);
> +	if (status) {
> +		dev_err(cdns_ctrl->dev, "erase operation failed\n");
> +		return -EIO;
> +	}
> +
> +	status = cadence_nand_cdma_finish(cdns_ctrl, cdns_ctrl->cdma_desc);
> +	if (status)
> +		return status;
> +
> +	return 0;
> +}
> +
> +static int cadence_nand_read_bbm(struct nand_chip *chip, int page, u8 *buf)
> +{
> +	int status;
> +	struct cdns_nand_ctrl *cdns_ctrl = to_cdns_nand_ctrl(chip->controller);
> +	struct cdns_nand_chip *cdns_chip = to_cdns_nand_chip(chip);
> +	struct mtd_info *mtd = nand_to_mtd(chip);
> +
> +	cadence_nand_prepare_data_size(chip, TT_BBM);
> +
> +	cadence_nand_set_skip_bytes_conf(cdns_ctrl, 0, 0, 0);
> +
> +	/*
> +	 * Read only bad block marker from offset
> +	 * defined by a memory manufacturer.
> +	 */
> +	status = cadence_nand_cdma_transfer(cdns_ctrl,
> +					    cdns_chip->cs[chip->cur_cs],
> +					    page, cdns_ctrl->buf, NULL,
> +					    mtd->oobsize,
> +					    0, DMA_FROM_DEVICE, false);
> +	if (status) {
> +		dev_err(cdns_ctrl->dev, "read BBM failed\n");
> +		return -EIO;
> +	}
> +
> +	memcpy(buf + cdns_chip->bbm_offs, cdns_ctrl->buf, cdns_chip->bbm_len);
> +
> +	return 0;
> +}

Not sure this function is relevant, see below.

> +
> +static int cadence_nand_write_page(struct nand_chip *chip,
> +				   const u8 *buf, int oob_required,
> +				   int page)
> +{
> +	struct cdns_nand_ctrl *cdns_ctrl = to_cdns_nand_ctrl(chip->controller);
> +	struct cdns_nand_chip *cdns_chip = to_cdns_nand_chip(chip);
> +	struct mtd_info *mtd = nand_to_mtd(chip);
> +	int status;
> +	u16 marker_val = 0xFFFF;
> +
> +	status = cadence_nand_select_target(chip);
> +	if (status)
> +		return status;
> +
> +	cadence_nand_set_skip_bytes_conf(cdns_ctrl, cdns_chip->bbm_len,
> +					 mtd->writesize
> +					 + cdns_chip->bbm_offs,
> +					 1);
> +
> +	if (oob_required) {
> +		marker_val = *(u16 *)(chip->oob_poi
> +				      + cdns_chip->bbm_offs);
> +	} else {
> +		/* Set oob data to 0xFF. */
> +		memset(cdns_ctrl->buf + mtd->writesize, 0xFF,
> +		       cdns_chip->avail_oob_size);
> +	}
> +
> +	cadence_nand_set_skip_marker_val(cdns_ctrl, marker_val);
> +
> +	cadence_nand_prepare_data_size(chip, TT_MAIN_OOB_AREA_EXT);
> +
> +	if (cadence_nand_dma_buf_ok(cdns_ctrl, buf, mtd->writesize) &&
> +	    cdns_ctrl->caps2.data_control_supp) {
> +		u8 *oob;
> +
> +		if (oob_required)
> +			oob = chip->oob_poi;
> +		else
> +			oob = cdns_ctrl->buf + mtd->writesize;
> +
> +		status = cadence_nand_cdma_transfer(cdns_ctrl,
> +						    cdns_chip->cs[chip->cur_cs],
> +						    page, (void *)buf, oob,
> +						    mtd->writesize,
> +						    cdns_chip->avail_oob_size,
> +						    DMA_TO_DEVICE, true);
> +		if (status) {
> +			dev_err(cdns_ctrl->dev, "write page failed\n");
> +			return -EIO;
> +		}
> +
> +		return 0;
> +	}
> +
> +	if (oob_required) {
> +		/* Transfer the data to the oob area. */
> +		memcpy(cdns_ctrl->buf + mtd->writesize, chip->oob_poi,
> +		       cdns_chip->avail_oob_size);
> +	}
> +
> +	memcpy(cdns_ctrl->buf, buf, mtd->writesize);
> +
> +	cadence_nand_prepare_data_size(chip, TT_MAIN_OOB_AREAS);
> +
> +	return cadence_nand_cdma_transfer(cdns_ctrl,
> +					  cdns_chip->cs[chip->cur_cs],
> +					  page, cdns_ctrl->buf, NULL,
> +					  mtd->writesize
> +					  + cdns_chip->avail_oob_size,
> +					  0, DMA_TO_DEVICE, true);
> +}
> +
> +static int cadence_nand_write_oob(struct nand_chip *chip, int page)
> +{
> +	struct cdns_nand_ctrl *cdns_ctrl = to_cdns_nand_ctrl(chip->controller);
> +	struct mtd_info *mtd = nand_to_mtd(chip);
> +
> +	memset(cdns_ctrl->buf, 0xFF, mtd->writesize);
> +
> +	return cadence_nand_write_page(chip, cdns_ctrl->buf, 1, page);
> +}
> +
> +static int cadence_nand_write_page_raw(struct nand_chip *chip,
> +				       const u8 *buf, int oob_required,
> +				       int page)
> +{
> +	struct cdns_nand_ctrl *cdns_ctrl = to_cdns_nand_ctrl(chip->controller);
> +	struct cdns_nand_chip *cdns_chip = to_cdns_nand_chip(chip);
> +	struct mtd_info *mtd = nand_to_mtd(chip);
> +	int writesize = mtd->writesize;
> +	int oobsize = mtd->oobsize;
> +	int ecc_steps = chip->ecc.steps;
> +	int ecc_size = chip->ecc.size;
> +	int ecc_bytes = chip->ecc.bytes;
> +	void *tmp_buf = cdns_ctrl->buf;
> +	int oob_skip = cdns_chip->bbm_len;
> +	size_t size = writesize + oobsize;
> +	int i, pos, len;
> +	int status = 0;
> +
> +	status = cadence_nand_select_target(chip);
> +	if (status)
> +		return status;
> +
> +	/*
> +	 * Fill the buffer with 0xff first except the full page transfer.
> +	 * This simplifies the logic.
> +	 */
> +	if (!buf || !oob_required)
> +		memset(tmp_buf, 0xff, size);
> +
> +	cadence_nand_set_skip_bytes_conf(cdns_ctrl, 0, 0, 0);
> +
> +	/* Arrange the buffer for syndrome payload/ecc layout. */
> +	if (buf) {
> +		for (i = 0; i < ecc_steps; i++) {
> +			pos = i * (ecc_size + ecc_bytes);
> +			len = ecc_size;
> +
> +			if (pos >= writesize)
> +				pos += oob_skip;
> +			else if (pos + len > writesize)
> +				len = writesize - pos;
> +
> +			memcpy(tmp_buf + pos, buf, len);
> +			buf += len;
> +			if (len < ecc_size) {
> +				len = ecc_size - len;
> +				memcpy(tmp_buf + writesize + oob_skip, buf,
> +				       len);
> +				buf += len;
> +			}
> +		}
> +	}
> +
> +	if (oob_required) {
> +		const u8 *oob = chip->oob_poi;
> +		u32 oob_data_offset = (cdns_chip->sector_count - 1) *
> +			(cdns_chip->sector_size + chip->ecc.bytes)
> +			+ cdns_chip->sector_size + oob_skip;
> +
> +		/* BBM at the beginning of the OOB area. */
> +		memcpy(tmp_buf + writesize, oob, oob_skip);
> +
> +		/* OOB free. */
> +		memcpy(tmp_buf + oob_data_offset, oob,
> +		       cdns_chip->avail_oob_size);
> +		oob += cdns_chip->avail_oob_size;
> +
> +		/* OOB ECC. */
> +		for (i = 0; i < ecc_steps; i++) {
> +			pos = ecc_size + i * (ecc_size + ecc_bytes);
> +			if (i == (ecc_steps - 1))
> +				pos += cdns_chip->avail_oob_size;
> +
> +			len = ecc_bytes;
> +
> +			if (pos >= writesize)
> +				pos += oob_skip;
> +			else if (pos + len > writesize)
> +				len = writesize - pos;
> +
> +			memcpy(tmp_buf + pos, oob, len);
> +			oob += len;
> +			if (len < ecc_bytes) {
> +				len = ecc_bytes - len;
> +				memcpy(tmp_buf + writesize + oob_skip, oob,
> +				       len);
> +				oob += len;
> +			}
> +		}
> +	}
> +
> +	cadence_nand_prepare_data_size(chip, TT_RAW_PAGE);
> +
> +	return cadence_nand_cdma_transfer(cdns_ctrl,
> +					  cdns_chip->cs[chip->cur_cs],
> +					  page, cdns_ctrl->buf, NULL,
> +					  mtd->writesize +
> +					  mtd->oobsize,
> +					  0, DMA_TO_DEVICE, false);
> +}
> +
> +static int cadence_nand_write_oob_raw(struct nand_chip *chip,
> +				      int page)
> +{
> +	return cadence_nand_write_page_raw(chip, NULL, true, page);
> +}
> +
> +static int cadence_nand_read_page(struct nand_chip *chip,
> +				  u8 *buf, int oob_required, int page)
> +{
> +	struct cdns_nand_ctrl *cdns_ctrl = to_cdns_nand_ctrl(chip->controller);
> +	struct cdns_nand_chip *cdns_chip = to_cdns_nand_chip(chip);
> +	struct mtd_info *mtd = nand_to_mtd(chip);
> +	int status = 0;
> +	int ecc_err_count = 0;
> +
> +	status = cadence_nand_select_target(chip);
> +	if (status)
> +		return status;
> +
> +	cadence_nand_set_skip_bytes_conf(cdns_ctrl, cdns_chip->bbm_len,
> +					 mtd->writesize
> +					 + cdns_chip->bbm_offs, 1);
> +
> +	/*
> +	 * If data buffer can be accessed by DMA and data_control feature
> +	 * is supported then transfer data and oob directly.
> +	 */
> +	if (cadence_nand_dma_buf_ok(cdns_ctrl, buf, mtd->writesize) &&
> +	    cdns_ctrl->caps2.data_control_supp) {
> +		u8 *oob;
> +
> +		if (oob_required)
> +			oob = chip->oob_poi;
> +		else
> +			oob = cdns_ctrl->buf + mtd->writesize;
> +
> +		cadence_nand_prepare_data_size(chip, TT_MAIN_OOB_AREA_EXT);
> +		status = cadence_nand_cdma_transfer(cdns_ctrl,
> +						    cdns_chip->cs[chip->cur_cs],
> +						    page, buf, oob,
> +						    mtd->writesize,
> +						    cdns_chip->avail_oob_size,
> +						    DMA_FROM_DEVICE, true);
> +	/* Otherwise use bounce buffer. */
> +	} else {
> +		cadence_nand_prepare_data_size(chip, TT_MAIN_OOB_AREAS);
> +		status = cadence_nand_cdma_transfer(cdns_ctrl,
> +						    cdns_chip->cs[chip->cur_cs],
> +						    page, cdns_ctrl->buf,
> +						    NULL, mtd->writesize
> +						    + cdns_chip->avail_oob_size,
> +						    0, DMA_FROM_DEVICE, true);
> +
> +		memcpy(buf, cdns_ctrl->buf, mtd->writesize);
> +		if (oob_required)
> +			memcpy(chip->oob_poi,
> +			       cdns_ctrl->buf + mtd->writesize,
> +			       mtd->oobsize);
> +	}
> +
> +	switch (status) {
> +	case STAT_ECC_UNCORR:
> +		mtd->ecc_stats.failed++;
> +		ecc_err_count++;
> +		break;
> +	case STAT_ECC_CORR:
> +		ecc_err_count = FIELD_GET(CDMA_CS_MAXERR,
> +					  cdns_ctrl->cdma_desc->status);
> +		mtd->ecc_stats.corrected += ecc_err_count;

Is this value the maximum number of bitflips in each chunk of the page?
If it returns the total number of bitflips corrected in the entire page
we have a problem.

> +		break;
> +	case STAT_ERASED:
> +	case STAT_OK:
> +		break;
> +	default:
> +		dev_err(cdns_ctrl->dev, "read page failed\n");
> +		return -EIO;
> +	}
> +
> +	if (oob_required)
> +		if (cadence_nand_read_bbm(chip, page, chip->oob_poi))
> +			return -EIO;

Do we really care about the BBM at this level? If we are requested to
read the page, I suppose we must do what is in our hands to return the
data? Normally this is handled in userspace directly.

> +
> +	return ecc_err_count;
> +}
> +
> +/* Reads OOB data from the device. */
> +static int cadence_nand_read_oob(struct nand_chip *chip, int page)
> +{
> +	struct cdns_nand_ctrl *cdns_ctrl = to_cdns_nand_ctrl(chip->controller);
> +
> +	return cadence_nand_read_page(chip, cdns_ctrl->buf, 1, page);
> +}
> +
> +static int cadence_nand_read_page_raw(struct nand_chip *chip,
> +				      u8 *buf, int oob_required, int page)
> +{
> +	struct cdns_nand_ctrl *cdns_ctrl = to_cdns_nand_ctrl(chip->controller);
> +	struct cdns_nand_chip *cdns_chip = to_cdns_nand_chip(chip);
> +	struct mtd_info *mtd = nand_to_mtd(chip);
> +	int oob_skip = cdns_chip->bbm_len;
> +	int writesize = mtd->writesize;
> +	int ecc_steps = chip->ecc.steps;
> +	int ecc_size = chip->ecc.size;
> +	int ecc_bytes = chip->ecc.bytes;
> +	void *tmp_buf = cdns_ctrl->buf;
> +	int i, pos, len;
> +	int status = 0;
> +
> +	status = cadence_nand_select_target(chip);
> +	if (status)
> +		return status;
> +
> +	cadence_nand_set_skip_bytes_conf(cdns_ctrl, 0, 0, 0);
> +
> +	cadence_nand_prepare_data_size(chip, TT_RAW_PAGE);
> +	status = cadence_nand_cdma_transfer(cdns_ctrl,
> +					    cdns_chip->cs[chip->cur_cs],
> +					    page, cdns_ctrl->buf, NULL,
> +					    mtd->writesize
> +					    + mtd->oobsize,
> +					    0, DMA_FROM_DEVICE, false);
> +
> +	switch (status) {
> +	case STAT_ERASED:
> +	case STAT_OK:
> +		break;
> +	default:
> +		dev_err(cdns_ctrl->dev, "read raw page failed\n");
> +		return -EIO;
> +	}
> +
> +	/* Arrange the buffer for syndrome payload/ecc layout. */
> +	if (buf) {
> +		for (i = 0; i < ecc_steps; i++) {
> +			pos = i * (ecc_size + ecc_bytes);
> +			len = ecc_size;
> +
> +			if (pos >= writesize)
> +				pos += oob_skip;
> +			else if (pos + len > writesize)
> +				len = writesize - pos;
> +
> +			memcpy(buf, tmp_buf + pos, len);
> +			buf += len;
> +			if (len < ecc_size) {
> +				len = ecc_size - len;
> +				memcpy(buf, tmp_buf + writesize + oob_skip,
> +				       len);
> +				buf += len;
> +			}
> +		}
> +	}
> +
> +	if (oob_required) {
> +		u8 *oob = chip->oob_poi;
> +		u32 oob_data_offset = (cdns_chip->sector_count - 1) *
> +			(cdns_chip->sector_size + chip->ecc.bytes)
> +			+ cdns_chip->sector_size + oob_skip;
> +
> +		/* OOB free. */
> +		memcpy(oob, tmp_buf + oob_data_offset,
> +		       cdns_chip->avail_oob_size);
> +
> +		/* BBM at the beginning of the OOB area. */
> +		memcpy(oob, tmp_buf + writesize, oob_skip);
> +
> +		oob += cdns_chip->avail_oob_size;
> +
> +		/* OOB ECC */
> +		for (i = 0; i < ecc_steps; i++) {
> +			pos = ecc_size + i * (ecc_size + ecc_bytes);
> +			len = ecc_bytes;
> +
> +			if (i == (ecc_steps - 1))
> +				pos += cdns_chip->avail_oob_size;
> +
> +			if (pos >= writesize)
> +				pos += oob_skip;
> +			else if (pos + len > writesize)
> +				len = writesize - pos;
> +
> +			memcpy(oob, tmp_buf + pos, len);
> +			oob += len;
> +			if (len < ecc_bytes) {
> +				len = ecc_bytes - len;
> +				memcpy(oob, tmp_buf + writesize + oob_skip,
> +				       len);
> +				oob += len;
> +			}
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int cadence_nand_read_oob_raw(struct nand_chip *chip,
> +				     int page)
> +{
> +	return cadence_nand_read_page_raw(chip, NULL, true, page);
> +}
> +
> +static void cadence_nand_slave_dma_transfer_finished(void *data)
> +{
> +	struct completion *finished = data;
> +
> +	complete(finished);
> +}
> +
> +static int cadence_nand_slave_dma_transfer(struct cdns_nand_ctrl *cdns_ctrl,
> +					   void *buf,
> +					   dma_addr_t dev_dma, size_t len,
> +					   enum dma_data_direction dir)
> +{
> +	DECLARE_COMPLETION_ONSTACK(finished);
> +	struct dma_chan *chan;
> +	struct dma_device *dma_dev;
> +	dma_addr_t src_dma, dst_dma, buf_dma;
> +	struct dma_async_tx_descriptor *tx;
> +	dma_cookie_t cookie;
> +
> +	chan = cdns_ctrl->dmac;
> +	dma_dev = chan->device;
> +
> +	buf_dma = dma_map_single(dma_dev->dev, buf, len, dir);
> +	if (dma_mapping_error(dma_dev->dev, buf_dma)) {
> +		dev_err(cdns_ctrl->dev, "Failed to map DMA buffer\n");
> +		goto err;
> +	}
> +
> +	if (dir == DMA_FROM_DEVICE) {
> +		src_dma = cdns_ctrl->io.dma;
> +		dst_dma = buf_dma;
> +	} else {
> +		src_dma = buf_dma;
> +		dst_dma = cdns_ctrl->io.dma;
> +	}
> +
> +	tx = dmaengine_prep_dma_memcpy(cdns_ctrl->dmac, dst_dma, src_dma, len,
> +				       DMA_CTRL_ACK | DMA_PREP_INTERRUPT);
> +	if (!tx) {
> +		dev_err(cdns_ctrl->dev, "Failed to prepare DMA memcpy\n");
> +		goto err_unmap;
> +	}
> +
> +	tx->callback = cadence_nand_slave_dma_transfer_finished;
> +	tx->callback_param = &finished;
> +
> +	cookie = dmaengine_submit(tx);
> +	if (dma_submit_error(cookie)) {
> +		dev_err(cdns_ctrl->dev, "Failed to do DMA tx_submit\n");
> +		goto err_unmap;
> +	}
> +
> +	dma_async_issue_pending(cdns_ctrl->dmac);
> +	wait_for_completion(&finished);
> +
> +	dma_unmap_single(cdns_ctrl->dev, buf_dma, len, dir);
> +
> +	return 0;
> +
> +err_unmap:
> +	dma_unmap_single(cdns_ctrl->dev, buf_dma, len, dir);
> +
> +err:
> +	dev_dbg(cdns_ctrl->dev, "Fall back to CPU I/O\n");
> +
> +	return -EIO;
> +}
> +
> +static int cadence_nand_read_buf(struct cdns_nand_ctrl *cdns_ctrl,
> +				 u8 *buf, int len)
> +{
> +	int len_aligned = ALIGN(len, cdns_ctrl->caps2.data_dma_width);
> +	u8 thread_nr = 0;
> +	u32 sdma_size;
> +	int status;
> +
> +	if (!cdns_ctrl->caps1->has_dma) {
> +		if (len & 3) {
> +			dev_err(cdns_ctrl->dev, "unaligned data\n");
> +			return -EIO;
> +		}
> +		readsl(cdns_ctrl->io.virt, buf, len / 4);
> +		return 0;
> +	}
> +
> +	/* Wait until slave DMA interface is ready to data transfer. */
> +	status = cadence_nand_wait_on_sdma(cdns_ctrl, &thread_nr, &sdma_size);
> +	if (status)
> +		return status;
> +
> +	if (sdma_size != len_aligned) {
> +		dev_err(cdns_ctrl->dev, "unexpected scenario\n");
> +		return -EIO;
> +	}
> +
> +	if (cdns_ctrl->dmac && cadence_nand_dma_buf_ok(cdns_ctrl, buf, len)) {
> +		status = cadence_nand_slave_dma_transfer(cdns_ctrl, buf,
> +							 cdns_ctrl->io.dma,
> +							 len, DMA_FROM_DEVICE);
> +		if (status == 0)
> +			return 0;
> +
> +		dev_warn(cdns_ctrl->dev,
> +			 "Slave DMA transfer failed. Try again using bounce buffer.");
> +	}
> +
> +	/* If DMA transfer is not possible or failed then use bounce buffer. */
> +	status = cadence_nand_slave_dma_transfer(cdns_ctrl, cdns_ctrl->buf,
> +						 cdns_ctrl->io.dma,
> +						 len_aligned, DMA_FROM_DEVICE);
> +
> +	if (status) {
> +		dev_err(cdns_ctrl->dev, "Slave DMA transfer failed");
> +		return status;
> +	}
> +
> +	memcpy(buf, cdns_ctrl->buf, len);
> +
> +	return 0;
> +}
> +
> +static int cadence_nand_write_buf(struct cdns_nand_ctrl *cdns_ctrl,
> +				  const u8 *buf, int len)
> +{
> +	u8 thread_nr = 0;
> +	u32 sdma_size;
> +	int status;
> +	int len_aligned = ALIGN(len, cdns_ctrl->caps2.data_dma_width);
> +
> +	if (!cdns_ctrl->caps1->has_dma) {
> +		if (len & 3) {
> +			dev_err(cdns_ctrl->dev, "unaligned data\n");
> +			return -EIO;
> +		}
> +		writesl(cdns_ctrl->io.virt, buf, len / 4);
> +		return 0;
> +	}
> +
> +	/* Wait until slave DMA interface is ready to data transfer. */
> +	status = cadence_nand_wait_on_sdma(cdns_ctrl, &thread_nr, &sdma_size);
> +	if (status)
> +		return status;
> +
> +	if (sdma_size != len_aligned) {
> +		dev_err(cdns_ctrl->dev, "Error unexpected scenario\n");
> +		return -EIO;
> +	}
> +
> +	if (cdns_ctrl->dmac && cadence_nand_dma_buf_ok(cdns_ctrl, buf, len)) {
> +		status = cadence_nand_slave_dma_transfer(cdns_ctrl, (void *)buf,
> +							 cdns_ctrl->io.dma,
> +							 len, DMA_TO_DEVICE);
> +		if (status == 0)
> +			return 0;
> +
> +		dev_warn(cdns_ctrl->dev,
> +			 "Slave DMA transfer failed. Try again using bounce buffer.");
> +	}
> +
> +	/* If DMA transfer is not possible or failed then use bounce buffer. */
> +	memcpy(cdns_ctrl->buf, buf, len);
> +
> +	status = cadence_nand_slave_dma_transfer(cdns_ctrl, cdns_ctrl->buf,
> +						 cdns_ctrl->io.dma,
> +						 len_aligned, DMA_TO_DEVICE);
> +
> +	if (status)
> +		dev_err(cdns_ctrl->dev, "Slave DMA transfer failed");
> +
> +	return status;
> +}
> +
> +static int cadence_nand_force_byte_access(struct nand_chip *chip,
> +					  bool force_8bit)
> +{
> +	struct cdns_nand_ctrl *cdns_ctrl = to_cdns_nand_ctrl(chip->controller);
> +	int status;
> +
> +	/*
> +	 * Callers of this function do not verify if the NAND is using a 16-bit
> +	 * an 8-bit bus for normal operations, so we need to take care of that
> +	 * here by leaving the configuration unchanged if the NAND does not have
> +	 * the NAND_BUSWIDTH_16 flag set.
> +	 */
> +	if (!(chip->options & NAND_BUSWIDTH_16))
> +		return 0;
> +
> +	status = cadence_nand_set_access_width16(cdns_ctrl, !force_8bit);
> +
> +	return status;
> +}
> +
> +static int cadence_nand_cmd_opcode(struct nand_chip *chip,
> +				   const struct nand_subop *subop)
> +{
> +	struct cdns_nand_ctrl *cdns_ctrl = to_cdns_nand_ctrl(chip->controller);
> +	struct cdns_nand_chip *cdns_chip = to_cdns_nand_chip(chip);
> +	const struct nand_op_instr *instr;
> +	unsigned int op_id = 0;
> +	u64 mini_ctrl_cmd = 0;
> +	int ret;
> +
> +	instr = &subop->instrs[op_id];
> +
> +	if (instr->delay_ns > 0)
> +		mini_ctrl_cmd |= GCMD_LAY_TWB;
> +
> +	mini_ctrl_cmd |= FIELD_PREP(GCMD_LAY_INSTR,
> +				    GCMD_LAY_INSTR_CMD);
> +	mini_ctrl_cmd |= FIELD_PREP(GCMD_LAY_INPUT_CMD,
> +				    instr->ctx.cmd.opcode);
> +
> +	ret = cadence_nand_generic_cmd_send(cdns_ctrl,
> +					    cdns_chip->cs[chip->cur_cs],
> +					    mini_ctrl_cmd);
> +	if (ret)
> +		dev_err(cdns_ctrl->dev, "send cmd %x failed\n",
> +			instr->ctx.cmd.opcode);
> +
> +	return ret;
> +}
> +
> +static int cadence_nand_cmd_address(struct nand_chip *chip,
> +				    const struct nand_subop *subop)
> +{
> +	struct cdns_nand_ctrl *cdns_ctrl = to_cdns_nand_ctrl(chip->controller);
> +	struct cdns_nand_chip *cdns_chip = to_cdns_nand_chip(chip);
> +	const struct nand_op_instr *instr;
> +	unsigned int op_id = 0;
> +	u64 mini_ctrl_cmd = 0;
> +	unsigned int offset, naddrs;
> +	u64 address = 0;
> +	const u8 *addrs;
> +	int ret;
> +	int i;
> +
> +	instr = &subop->instrs[op_id];
> +
> +	if (instr->delay_ns > 0)
> +		mini_ctrl_cmd |= GCMD_LAY_TWB;
> +
> +	mini_ctrl_cmd |= FIELD_PREP(GCMD_LAY_INSTR,
> +				    GCMD_LAY_INSTR_ADDR);
> +
> +	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];
> +
> +	for (i = 0; i < naddrs; i++)
> +		address |= (u64)addrs[i] << (8 * i);
> +
> +	mini_ctrl_cmd |= FIELD_PREP(GCMD_LAY_INPUT_ADDR,
> +				    address);
> +	mini_ctrl_cmd |= FIELD_PREP(GCMD_LAY_INPUT_ADDR_SIZE,
> +				    naddrs - 1);
> +
> +	ret = cadence_nand_generic_cmd_send(cdns_ctrl,
> +					    cdns_chip->cs[chip->cur_cs],
> +					    mini_ctrl_cmd);
> +	if (ret)
> +		dev_err(cdns_ctrl->dev, "send address %llx failed\n", address);
> +
> +	return ret;
> +}
> +
> +static int cadence_nand_cmd_erase(struct nand_chip *chip,
> +				  const struct nand_subop *subop)
> +{
> +	unsigned int op_id;
> +
> +	if (subop->instrs[0].ctx.cmd.opcode == NAND_CMD_ERASE1) {
> +		int i;
> +		const struct nand_op_instr *instr = NULL;
> +		unsigned int offset, naddrs;
> +		const u8 *addrs;
> +		u32 page = 0;
> +
> +		instr = &subop->instrs[1];
> +		offset = nand_subop_get_addr_start_off(subop, 1);
> +		naddrs = nand_subop_get_num_addr_cyc(subop, 1);
> +		addrs = &instr->ctx.addr.addrs[offset];
> +
> +		for (i = 0; i < naddrs; i++)
> +			page |= (u32)addrs[i] << (8 * i);
> +
> +		return cadence_nand_erase(chip, page);
> +	}
> +
> +	/*
> +	 * If it is not an erase operation then handle operation
> +	 * by calling exec_op function.
> +	 */
> +	for (op_id = 0; op_id < subop->ninstrs; op_id++) {
> +		int ret;
> +		const struct nand_operation nand_op = {
> +			.cs = chip->cur_cs,
> +			.instrs =  &subop->instrs[op_id],
> +			.ninstrs = 1};
> +		ret = chip->controller->ops->exec_op(chip, &nand_op, false);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int cadence_nand_cmd_data(struct nand_chip *chip,
> +				 const struct nand_subop *subop)
> +{
> +	struct cdns_nand_ctrl *cdns_ctrl = to_cdns_nand_ctrl(chip->controller);
> +	struct cdns_nand_chip *cdns_chip = to_cdns_nand_chip(chip);
> +	const struct nand_op_instr *instr;
> +	unsigned int offset, op_id = 0;
> +	u64 mini_ctrl_cmd = 0;
> +	int len = 0;
> +	int ret;
> +
> +	instr = &subop->instrs[op_id];
> +
> +	if (instr->delay_ns > 0)
> +		mini_ctrl_cmd |= GCMD_LAY_TWB;
> +
> +	mini_ctrl_cmd |= FIELD_PREP(GCMD_LAY_INSTR,
> +				    GCMD_LAY_INSTR_DATA);
> +
> +	if (instr->type == NAND_OP_DATA_OUT_INSTR)
> +		mini_ctrl_cmd |= FIELD_PREP(GCMD_DIR,
> +					    GCMD_DIR_WRITE);
> +
> +	len = nand_subop_get_data_len(subop, op_id);
> +	offset = nand_subop_get_data_start_off(subop, op_id);
> +	mini_ctrl_cmd |= FIELD_PREP(GCMD_SECT_CNT, 1);
> +	mini_ctrl_cmd |= FIELD_PREP(GCMD_LAST_SIZE, len);
> +	if (instr->ctx.data.force_8bit) {
> +		ret = cadence_nand_force_byte_access(chip, true);
> +		if (ret) {
> +			dev_err(cdns_ctrl->dev,
> +				"cannot change byte access generic data cmd failed\n");
> +			return ret;
> +		}
> +	}
> +
> +	ret = cadence_nand_generic_cmd_send(cdns_ctrl,
> +					    cdns_chip->cs[chip->cur_cs],
> +					    mini_ctrl_cmd);
> +	if (ret) {
> +		dev_err(cdns_ctrl->dev, "send generic data cmd failed\n");
> +		return ret;
> +	}
> +
> +	if (instr->type == NAND_OP_DATA_IN_INSTR) {
> +		void *buf = instr->ctx.data.buf.in + offset;
> +
> +		ret = cadence_nand_read_buf(cdns_ctrl, buf, len);
> +	} else {
> +		const void *buf = instr->ctx.data.buf.out + offset;
> +
> +		ret = cadence_nand_write_buf(cdns_ctrl, buf, len);
> +	}
> +
> +	if (ret) {
> +		dev_err(cdns_ctrl->dev, "data transfer failed for generic command\n");
> +		return ret;
> +	}
> +
> +	if (instr->ctx.data.force_8bit) {
> +		ret = cadence_nand_force_byte_access(chip, false);
> +		if (ret) {
> +			dev_err(cdns_ctrl->dev,
> +				"cannot change byte access generic data cmd failed\n");
> +		}
> +	}
> +
> +	return ret;
> +}
> +
> +static int cadence_nand_cmd_waitrdy(struct nand_chip *chip,
> +				    const struct nand_subop *subop)
> +{
> +	int status;
> +	unsigned int op_id = 0;
> +	struct cdns_nand_ctrl *cdns_ctrl = to_cdns_nand_ctrl(chip->controller);
> +	struct cdns_nand_chip *cdns_chip = to_cdns_nand_chip(chip);
> +	const struct nand_op_instr *instr = &subop->instrs[op_id];
> +	u32 timeout_us = instr->ctx.waitrdy.timeout_ms * 1000;
> +
> +	status = cadence_nand_wait_for_value(cdns_ctrl, RBN_SETINGS,
> +					     timeout_us,
> +					     1U << cdns_chip->cs[chip->cur_cs],

                                             BIT() ?

> +					     false);
> +	return status;
> +}
> +
> +static const struct nand_op_parser cadence_nand_op_parser = NAND_OP_PARSER(
> +	NAND_OP_PARSER_PATTERN(
> +		cadence_nand_cmd_erase,
> +		NAND_OP_PARSER_PAT_CMD_ELEM(false),
> +		NAND_OP_PARSER_PAT_ADDR_ELEM(false, MAX_ERASE_ADDRESS_CYC),
> +		NAND_OP_PARSER_PAT_CMD_ELEM(false),
> +		NAND_OP_PARSER_PAT_WAITRDY_ELEM(false)),
> +	NAND_OP_PARSER_PATTERN(
> +		cadence_nand_cmd_opcode,
> +		NAND_OP_PARSER_PAT_CMD_ELEM(false)),
> +	NAND_OP_PARSER_PATTERN(
> +		cadence_nand_cmd_address,
> +		NAND_OP_PARSER_PAT_ADDR_ELEM(false, MAX_ADDRESS_CYC)),
> +	NAND_OP_PARSER_PATTERN(
> +		cadence_nand_cmd_data,
> +		NAND_OP_PARSER_PAT_DATA_IN_ELEM(false, MAX_DATA_SIZE)),
> +	NAND_OP_PARSER_PATTERN(
> +		cadence_nand_cmd_data,
> +		NAND_OP_PARSER_PAT_DATA_OUT_ELEM(false, MAX_DATA_SIZE)),
> +	NAND_OP_PARSER_PATTERN(
> +		cadence_nand_cmd_waitrdy,
> +		NAND_OP_PARSER_PAT_WAITRDY_ELEM(false))
> +	);
> +
> +static int cadence_nand_exec_op(struct nand_chip *chip,
> +				const struct nand_operation *op,
> +				bool check_only)
> +{
> +	int status = cadence_nand_select_target(chip);
> +
> +	if (status)
> +		return status;
> +
> +	return nand_op_parser_exec_op(chip, &cadence_nand_op_parser, op,
> +				      check_only);
> +}
> +
> +static int cadence_nand_ooblayout_free(struct mtd_info *mtd, int section,
> +				       struct mtd_oob_region *oobregion)
> +{
> +	struct nand_chip *chip = mtd_to_nand(mtd);
> +	struct cdns_nand_chip *cdns_chip = to_cdns_nand_chip(chip);
> +
> +	if (section)
> +		return -ERANGE;
> +
> +	oobregion->offset = cdns_chip->bbm_len;
> +	oobregion->length = cdns_chip->avail_oob_size
> +		- cdns_chip->bbm_len;
> +
> +	return 0;
> +}
> +
> +static int cadence_nand_ooblayout_ecc(struct mtd_info *mtd, int section,
> +				      struct mtd_oob_region *oobregion)
> +{
> +	struct nand_chip *chip = mtd_to_nand(mtd);
> +	struct cdns_nand_chip *cdns_chip = to_cdns_nand_chip(chip);
> +
> +	if (section)
> +		return -ERANGE;
> +
> +	oobregion->offset = cdns_chip->avail_oob_size;
> +	oobregion->length = chip->ecc.total;
> +
> +	return 0;
> +}
> +
> +static const struct mtd_ooblayout_ops cadence_nand_ooblayout_ops = {
> +	.free = cadence_nand_ooblayout_free,
> +	.ecc = cadence_nand_ooblayout_ecc,
> +};
> +
> +static int calc_cycl(u32 timing, u32 clock)
> +{
> +	if (timing == 0 || clock == 0)
> +		return 0;
> +
> +	if ((timing % clock) > 0)
> +		return timing / clock;
> +	else
> +		return timing / clock - 1;
> +}
> +
> +/* Calculate max data valid window. */
> +static inline u32 calc_tdvw_max(u32 trp_cnt, u32 clk_period, u32 trhoh_min,
> +				u32 board_delay_skew_min, u32 ext_mode)
> +{
> +	if (ext_mode == 0)
> +		clk_period /= 2;
> +
> +	return (trp_cnt + 1) * clk_period + trhoh_min +
> +		board_delay_skew_min;
> +}
> +
> +/* Calculate data valid window. */
> +static inline u32 calc_tdvw(u32 trp_cnt, u32 clk_period, u32 trhoh_min,
> +			    u32 trea_max, u32 ext_mode)
> +{
> +	if (ext_mode == 0)
> +		clk_period /= 2;
> +
> +	return (trp_cnt + 1) * clk_period + trhoh_min - trea_max;
> +}
> +
> +static int
> +cadence_nand_setup_data_interface(struct nand_chip *chip, int chipnr,
> +				  const struct nand_data_interface *conf)
> +{
> +	const struct nand_sdr_timings *sdr;
> +	struct cdns_nand_ctrl *cdns_ctrl = to_cdns_nand_ctrl(chip->controller);
> +	struct cdns_nand_chip *cdns_chip = to_cdns_nand_chip(chip);
> +	struct cadence_nand_timings *t = &cdns_chip->timings;
> +	u32 reg;
> +	u32 board_delay = cdns_ctrl->board_delay;
> +	u32 clk_period = DIV_ROUND_DOWN_ULL(1000000000000ULL,
> +					    cdns_ctrl->nf_clk_rate);
> +	u32 tceh_cnt, tcs_cnt, tadl_cnt, tccs_cnt;
> +	u32 tfeat_cnt, trhz_cnt, tvdly_cnt;
> +	u32 trhw_cnt, twb_cnt, twh_cnt = 0, twhr_cnt;
> +	u32 twp_cnt = 0, trp_cnt = 0, trh_cnt = 0;
> +	u32 if_skew = cdns_ctrl->caps1->if_skew;
> +	u32 board_delay_skew_min = board_delay - if_skew;
> +	u32 board_delay_skew_max = board_delay + if_skew;
> +	u32 dqs_sampl_res, phony_dqs_mod;
> +	u32 tdvw, tdvw_min, tdvw_max;
> +	u32 ext_rd_mode, ext_wr_mode;
> +	u32 dll_phy_dqs_timing = 0, phony_dqs_timing = 0, rd_del_sel = 0;
> +	u32 sampling_point;
> +
> +	sdr = nand_get_sdr_timings(conf);
> +	if (IS_ERR(sdr))
> +		return PTR_ERR(sdr);
> +
> +	memset(t, 0, sizeof(*t));
> +	/* Sampling point calculation. */
> +
> +	if (cdns_ctrl->caps2.is_phy_type_dll)
> +		phony_dqs_mod = 2;
> +	else
> +		phony_dqs_mod = 1;
> +
> +	dqs_sampl_res = clk_period / phony_dqs_mod;
> +
> +	tdvw_min = sdr->tREA_max + board_delay_skew_max;
> +	/*
> +	 * The idea of those calculation is to get the optimum value
> +	 * for tRP and tRH timings. If it is NOT possible to sample data
> +	 * with optimal tRP/tRH settings, the parameters will be extended.
> +	 * If clk_period is 50ns (the lowest value) this condition is met
> +	 * for asynchronous timing modes 1, 2, 3, 4 and 5.
> +	 * If clk_period is 20ns the condition is met only
> +	 * for asynchronous timing mode 5.
> +	 */
> +	if (sdr->tRC_min <= clk_period &&
> +	    sdr->tRP_min <= (clk_period / 2) &&
> +	    sdr->tREH_min <= (clk_period / 2)) {
> +		/* Performance mode. */
> +		ext_rd_mode = 0;
> +		tdvw = calc_tdvw(trp_cnt, clk_period, sdr->tRHOH_min,
> +				 sdr->tREA_max, ext_rd_mode);
> +		tdvw_max = calc_tdvw_max(trp_cnt, clk_period, sdr->tRHOH_min,
> +					 board_delay_skew_min,
> +					 ext_rd_mode);
> +		/*
> +		 * Check if data valid window and sampling point can be found
> +		 * and is not on the edge (ie. we have hold margin).
> +		 * If not extend the tRP timings.
> +		 */
> +		if (tdvw > 0) {
> +			if (tdvw_max <= tdvw_min ||
> +			    (tdvw_max % dqs_sampl_res) == 0) {
> +				/*
> +				 * No valid sampling point so the RE pulse need
> +				 * to be widen widening by half clock cycle.
> +				 */
> +				ext_rd_mode = 1;
> +			}
> +		} else {
> +			/*
> +			 * There is no valid window
> +			 * to be able to sample data the tRP need to be widen.
> +			 * Very safe calculations are performed here.
> +			 */
> +			trp_cnt = (sdr->tREA_max + board_delay_skew_max
> +				   + dqs_sampl_res) / clk_period;
> +			ext_rd_mode = 1;
> +		}
> +
> +	} else {
> +		/* Extended read mode. */
> +		u32 trh;
> +
> +		ext_rd_mode = 1;
> +		trp_cnt = calc_cycl(sdr->tRP_min, clk_period);
> +		trh = sdr->tRC_min - ((trp_cnt + 1) * clk_period);
> +		if (sdr->tREH_min >= trh)
> +			trh_cnt = calc_cycl(sdr->tREH_min, clk_period);
> +		else
> +			trh_cnt = calc_cycl(trh, clk_period);
> +
> +		tdvw = calc_tdvw(trp_cnt, clk_period, sdr->tRHOH_min,
> +				 sdr->tREA_max, ext_rd_mode);
> +		/*
> +		 * Check if data valid window and sampling point can be found
> +		 * or if it is at the edge check if previous is valid
> +		 * - if not extend the tRP timings.
> +		 */
> +		if (tdvw > 0) {
> +			tdvw_max = calc_tdvw_max(trp_cnt, clk_period,
> +						 sdr->tRHOH_min,
> +						 board_delay_skew_min,
> +						 ext_rd_mode);
> +
> +			if ((((tdvw_max / dqs_sampl_res)
> +			      * dqs_sampl_res) <= tdvw_min) ||
> +			    (((tdvw_max % dqs_sampl_res) == 0) &&
> +			     (((tdvw_max / dqs_sampl_res - 1)
> +			       * dqs_sampl_res) <= tdvw_min))) {
> +				/*
> +				 * Data valid window width is lower than
> +				 * sampling resolution and do not hit any
> +				 * sampling point to be sure the sampling point
> +				 * will be found the RE low pulse width will be
> +				 *  extended by one clock cycle.
> +				 */
> +				trp_cnt = trp_cnt + 1;
> +			}
> +		} else {
> +			/*
> +			 * There is no valid window to be able to sample data.
> +			 * The tRP need to be widen.
> +			 * Very safe calculations are performed here.
> +			 */
> +			trp_cnt = (sdr->tREA_max + board_delay_skew_max
> +				   + dqs_sampl_res) / clk_period;
> +		}
> +	}
> +
> +	tdvw_max = calc_tdvw_max(trp_cnt, clk_period,
> +				 sdr->tRHOH_min,
> +				 board_delay_skew_min, ext_rd_mode);
> +
> +	if (sdr->tWC_min <= clk_period &&
> +	    (sdr->tWP_min + if_skew) <= (clk_period / 2) &&
> +	    (sdr->tWH_min + if_skew) <= (clk_period / 2)) {
> +		ext_wr_mode = 0;
> +	} else {
> +		u32 twh;
> +
> +		ext_wr_mode = 1;
> +		twp_cnt = calc_cycl(sdr->tWP_min + if_skew, clk_period);
> +		if ((twp_cnt + 1) * clk_period < (sdr->tALS_min + if_skew))
> +			twp_cnt = calc_cycl(sdr->tALS_min + if_skew,
> +					    clk_period);
> +
> +		twh = (sdr->tWC_min - (twp_cnt + 1) * clk_period);
> +		if (sdr->tWH_min >= twh)
> +			twh = sdr->tWH_min;
> +
> +		twh_cnt = calc_cycl(twh + if_skew, clk_period);
> +	}
> +
> +	reg = FIELD_PREP(ASYNC_TOGGLE_TIMINGS_TRH, trh_cnt);
> +	reg |= FIELD_PREP(ASYNC_TOGGLE_TIMINGS_TRP, trp_cnt);
> +	reg |= FIELD_PREP(ASYNC_TOGGLE_TIMINGS_TWH, twh_cnt);
> +	reg |= FIELD_PREP(ASYNC_TOGGLE_TIMINGS_TWP, twp_cnt);
> +	t->async_toggle_timings = reg;
> +	dev_dbg(cdns_ctrl->dev, "ASYNC_TOGGLE_TIMINGS_SDR\t%x\n", reg);
> +
> +	tadl_cnt = calc_cycl((sdr->tADL_min + if_skew), clk_period);
> +	tccs_cnt = calc_cycl((sdr->tCCS_min + if_skew), clk_period);
> +	twhr_cnt = calc_cycl((sdr->tWHR_min + if_skew), clk_period);
> +	trhw_cnt = calc_cycl((sdr->tRHW_min + if_skew), clk_period);
> +	reg = FIELD_PREP(TIMINGS0_TADL, tadl_cnt);
> +
> +	/*
> +	 * If timing exceeds delay field in timing register
> +	 * then use maximum value.
> +	 */
> +	if (FIELD_FIT(TIMINGS0_TCCS, tccs_cnt))
> +		reg |= FIELD_PREP(TIMINGS0_TCCS, tccs_cnt);
> +	else
> +		reg |= TIMINGS0_TCCS;
> +
> +	reg |= FIELD_PREP(TIMINGS0_TWHR, twhr_cnt);
> +	reg |= FIELD_PREP(TIMINGS0_TRHW, trhw_cnt);
> +	t->timings0 = reg;
> +	dev_dbg(cdns_ctrl->dev, "TIMINGS0_SDR\t%x\n", reg);
> +
> +	/* The following is related to single signal so skew is not needed. */
> +	trhz_cnt = calc_cycl(sdr->tRHZ_max, clk_period);
> +	trhz_cnt = trhz_cnt + 1;
> +	twb_cnt = calc_cycl((sdr->tWB_max + board_delay), clk_period);
> +	/*
> +	 * Because of the two stage syncflop the value must be increased by 3
> +	 * first value is related with sync, second value is related
> +	 * with output if delay.
> +	 */
> +	twb_cnt = twb_cnt + 3 + 5;
> +	/*
> +	 * The following is related to the we edge of the random data input
> +	 * sequence so skew is not needed.
> +	 */
> +	tvdly_cnt = calc_cycl(500000 + if_skew, clk_period);
> +	reg = FIELD_PREP(TIMINGS1_TRHZ, trhz_cnt);
> +	reg |= FIELD_PREP(TIMINGS1_TWB, twb_cnt);
> +	reg |= FIELD_PREP(TIMINGS1_TVDLY, tvdly_cnt);
> +	t->timings1 = reg;
> +	dev_dbg(cdns_ctrl->dev, "TIMINGS1_SDR\t%x\n", reg);
> +
> +	tfeat_cnt = calc_cycl(sdr->tFEAT_max, clk_period);
> +	if (tfeat_cnt < twb_cnt)
> +		tfeat_cnt = twb_cnt;
> +
> +	tceh_cnt = calc_cycl(sdr->tCEH_min, clk_period);
> +	tcs_cnt = calc_cycl((sdr->tCS_min + if_skew), clk_period);
> +
> +	reg = FIELD_PREP(TIMINGS2_TFEAT, tfeat_cnt);
> +	reg |= FIELD_PREP(TIMINGS2_CS_HOLD_TIME, tceh_cnt);
> +	reg |= FIELD_PREP(TIMINGS2_CS_SETUP_TIME, tcs_cnt);
> +	t->timings2 = reg;
> +	dev_dbg(cdns_ctrl->dev, "TIMINGS2_SDR\t%x\n", reg);
> +
> +	if (cdns_ctrl->caps2.is_phy_type_dll) {
> +		reg = DLL_PHY_CTRL_DLL_RST_N;
> +		if (ext_wr_mode)
> +			reg |= DLL_PHY_CTRL_EXTENDED_WR_MODE;
> +		if (ext_rd_mode)
> +			reg |= DLL_PHY_CTRL_EXTENDED_RD_MODE;
> +
> +		reg |= FIELD_PREP(DLL_PHY_CTRL_RS_HIGH_WAIT_CNT, 7);
> +		reg |= FIELD_PREP(DLL_PHY_CTRL_RS_IDLE_CNT, 7);
> +		t->dll_phy_ctrl = reg;
> +		dev_dbg(cdns_ctrl->dev, "DLL_PHY_CTRL_SDR\t%x\n", reg);
> +	}
> +
> +	/* Sampling point calculation. */
> +	if ((tdvw_max % dqs_sampl_res) > 0)
> +		sampling_point = tdvw_max / dqs_sampl_res;
> +	else
> +		sampling_point = (tdvw_max / dqs_sampl_res - 1);
> +
> +	if (sampling_point * dqs_sampl_res > tdvw_min) {
> +		dll_phy_dqs_timing =
> +			FIELD_PREP(PHY_DQS_TIMING_DQS_SEL_OE_END, 4);
> +		dll_phy_dqs_timing |= PHY_DQS_TIMING_USE_PHONY_DQS;
> +		phony_dqs_timing = sampling_point / phony_dqs_mod;
> +
> +		if ((sampling_point % 2) > 0) {
> +			dll_phy_dqs_timing |= PHY_DQS_TIMING_PHONY_DQS_SEL;
> +			if ((tdvw_max % dqs_sampl_res) == 0)
> +				/*
> +				 * Calculation for sampling point at the edge
> +				 * of data and being odd number.
> +				 */
> +				phony_dqs_timing = (tdvw_max / dqs_sampl_res)
> +					/ phony_dqs_mod - 1;
> +
> +			if (!cdns_ctrl->caps2.is_phy_type_dll)
> +				phony_dqs_timing--;
> +
> +		} else {
> +			phony_dqs_timing--;
> +		}
> +		rd_del_sel = phony_dqs_timing + 3;
> +	} else {
> +		dev_warn(cdns_ctrl->dev,
> +			 "ERROR : cannot find valid sampling point\n");
> +	}
> +
> +	reg = FIELD_PREP(PHY_CTRL_PHONY_DQS, phony_dqs_timing);
> +	if (cdns_ctrl->caps2.is_phy_type_dll)
> +		reg  |= PHY_CTRL_SDR_DQS;
> +	t->phy_ctrl = reg;
> +	dev_dbg(cdns_ctrl->dev, "PHY_CTRL_REG_SDR\t%x\n", reg);
> +
> +	if (cdns_ctrl->caps2.is_phy_type_dll) {
> +		dev_dbg(cdns_ctrl->dev, "PHY_TSEL_REG_SDR\t%x\n", 0);
> +		dev_dbg(cdns_ctrl->dev, "PHY_DQ_TIMING_REG_SDR\t%x\n", 2);
> +		dev_dbg(cdns_ctrl->dev, "PHY_DQS_TIMING_REG_SDR\t%x\n",
> +			dll_phy_dqs_timing);
> +		t->phy_dqs_timing = dll_phy_dqs_timing;
> +
> +		reg = FIELD_PREP(PHY_GATE_LPBK_CTRL_RDS, rd_del_sel);
> +		dev_dbg(cdns_ctrl->dev, "PHY_GATE_LPBK_CTRL_REG_SDR\t%x\n",
> +			reg);
> +		t->phy_gate_lpbk_ctrl = reg;
> +
> +		dev_dbg(cdns_ctrl->dev, "PHY_DLL_MASTER_CTRL_REG_SDR\t%lx\n",
> +			PHY_DLL_MASTER_CTRL_BYPASS_MODE);
> +		dev_dbg(cdns_ctrl->dev, "PHY_DLL_SLAVE_CTRL_REG_SDR\t%x\n", 0);
> +	}
> +
> +	return 0;
> +}
> +
> +int cadence_nand_attach_chip(struct nand_chip *chip)
> +{
> +	struct cdns_nand_ctrl *cdns_ctrl = to_cdns_nand_ctrl(chip->controller);
> +	struct cdns_nand_chip *cdns_chip = to_cdns_nand_chip(chip);
> +	struct mtd_info *mtd = nand_to_mtd(chip);
> +	u32 max_oob_data_size;
> +	int ret;
> +
> +	if (chip->options & NAND_BUSWIDTH_16) {
> +		ret = cadence_nand_set_access_width16(cdns_ctrl, true);
> +		if (ret)
> +			goto free_buf;
> +	}
> +
> +	chip->bbt_options |= NAND_BBT_USE_FLASH;
> +	chip->bbt_options |= NAND_BBT_NO_OOB;
> +	chip->ecc.mode = NAND_ECC_HW;
> +
> +	chip->options |= NAND_NO_SUBPAGE_WRITE;
> +
> +	cdns_chip->bbm_offs = chip->badblockpos;
> +	if (chip->options & NAND_BUSWIDTH_16) {
> +		cdns_chip->bbm_offs &= ~0x01;
> +		cdns_chip->bbm_len = 2;
> +	} else {
> +		cdns_chip->bbm_len = 1;
> +	}
> +
> +	ret = nand_ecc_choose_conf(chip,
> +				   &cdns_ctrl->ecc_caps,
> +				   mtd->oobsize - cdns_chip->bbm_len);
> +	if (ret) {
> +		dev_err(cdns_ctrl->dev, "ECC configuration failed\n");
> +		goto free_buf;
> +	}
> +
> +	dev_dbg(cdns_ctrl->dev,
> +		"chosen ECC settings: step=%d, strength=%d, bytes=%d\n",
> +		chip->ecc.size, chip->ecc.strength, chip->ecc.bytes);
> +
> +	/* Error correction configuration. */
> +	cdns_chip->sector_size = chip->ecc.size;
> +	cdns_chip->sector_count = mtd->writesize / cdns_chip->sector_size;
> +
> +	cdns_chip->avail_oob_size = mtd->oobsize
> +		- cdns_chip->sector_count * chip->ecc.bytes;
> +
> +	max_oob_data_size = MAX_OOB_SIZE_PER_SECTOR;
> +
> +	if (cdns_chip->avail_oob_size > max_oob_data_size)
> +		cdns_chip->avail_oob_size = max_oob_data_size;
> +
> +	if ((cdns_chip->avail_oob_size + cdns_chip->bbm_len
> +	     + cdns_chip->sector_count
> +	     * chip->ecc.bytes) > mtd->oobsize)

If the line is not readable enough you can use intermediate variables.
Also the priority of the '*' operator could be enforced with
parenthesis. Really this is just a nit pick :)

> +		cdns_chip->avail_oob_size -= 4;
> +
> +	cdns_chip->corr_str_idx =
> +		cadence_nand_get_ecc_strength_idx(cdns_ctrl,
> +						  chip->ecc.strength);
> +	if (cdns_chip->corr_str_idx < 0)
> +		return -EINVAL;
> +
> +	if (cadence_nand_wait_for_value(cdns_ctrl, CTRL_STATUS,
> +					1000000,
> +					CTRL_STATUS_CTRL_BUSY, true))
> +		return -ETIMEDOUT;
> +
> +	cadence_nand_set_ecc_strength(cdns_ctrl,
> +				      cdns_chip->corr_str_idx);
> +
> +	cadence_nand_set_erase_detection(cdns_ctrl, true,
> +					 chip->ecc.strength);
> +
> +	/* Override the default read operations. */
> +	chip->ecc.read_page = cadence_nand_read_page;
> +	chip->ecc.read_page_raw = cadence_nand_read_page_raw;
> +	chip->ecc.write_page = cadence_nand_write_page;
> +	chip->ecc.write_page_raw = cadence_nand_write_page_raw;
> +	chip->ecc.read_oob = cadence_nand_read_oob;
> +	chip->ecc.write_oob = cadence_nand_write_oob;
> +	chip->ecc.read_oob_raw = cadence_nand_read_oob_raw;
> +	chip->ecc.write_oob_raw = cadence_nand_write_oob_raw;
> +
> +	if ((mtd->writesize + mtd->oobsize) > cdns_ctrl->buf_size) {
> +		cdns_ctrl->buf_size = mtd->writesize + mtd->oobsize;
> +		kfree(cdns_ctrl->buf);
> +		cdns_ctrl->buf = kzalloc(cdns_ctrl->buf_size, GFP_KERNEL);
> +		if (!cdns_ctrl->buf) {
> +			ret = -ENOMEM;
> +			goto free_buf;
> +		}
> +	}
> +
> +	/* Is 32-bit DMA supported? */
> +	ret = dma_set_mask(cdns_ctrl->dev, DMA_BIT_MASK(32));
> +	if (ret) {
> +		dev_err(cdns_ctrl->dev, "no usable DMA configuration\n");
> +		goto free_buf;
> +	}
> +
> +	mtd_set_ooblayout(mtd, &cadence_nand_ooblayout_ops);
> +
> +	return 0;
> +
> +free_buf:
> +	kfree(cdns_ctrl->buf);
> +
> +	return ret;
> +}
> +
> +static const struct nand_controller_ops cadence_nand_controller_ops = {
> +	.attach_chip = cadence_nand_attach_chip,
> +	.exec_op = cadence_nand_exec_op,
> +	.setup_data_interface = cadence_nand_setup_data_interface,
> +};
> +
> +static int cadence_nand_chip_init(struct cdns_nand_ctrl *cdns_ctrl,
> +				  struct device_node *np)
> +{
> +	struct cdns_nand_chip *cdns_chip;
> +	struct mtd_info *mtd;
> +	struct nand_chip *chip;
> +	int nsels, ret, i;
> +	u32 cs;
> +
> +	nsels = of_property_count_elems_of_size(np, "reg", sizeof(u32));
> +	if (nsels <= 0) {
> +		dev_err(cdns_ctrl->dev, "missing/invalid reg property\n");
> +		return -EINVAL;
> +	}
> +
> +	/* Allocate the nand chip structure. */
> +	cdns_chip = devm_kzalloc(cdns_ctrl->dev, sizeof(*cdns_chip) +
> +				 (nsels * sizeof(u8)),
> +				 GFP_KERNEL);
> +	if (!cdns_chip) {
> +		dev_err(cdns_ctrl->dev, "could not allocate chip structure\n");
> +		return -ENOMEM;
> +	}
> +
> +	cdns_chip->nsels = nsels;
> +
> +	for (i = 0; i < nsels; i++) {
> +		/* Retrieve CS id. */
> +		ret = of_property_read_u32_index(np, "reg", i, &cs);
> +		if (ret) {
> +			dev_err(cdns_ctrl->dev,
> +				"could not retrieve reg property: %d\n",
> +				ret);
> +			return ret;
> +		}
> +
> +		if (cs >= cdns_ctrl->caps2.max_banks) {
> +			dev_err(cdns_ctrl->dev,
> +				"invalid reg value: %u (max CS = %d)\n",
> +				cs, cdns_ctrl->caps2.max_banks);
> +			return -EINVAL;
> +		}
> +
> +		if (test_and_set_bit(cs, &cdns_ctrl->assigned_cs)) {
> +			dev_err(cdns_ctrl->dev,
> +				"CS %d already assigned\n", cs);
> +			return -EINVAL;
> +		}
> +
> +		cdns_chip->cs[i] = cs;
> +	}
> +
> +	chip = &cdns_chip->chip;
> +	chip->controller = &cdns_ctrl->controller;
> +	nand_set_flash_node(chip, np);
> +
> +	mtd = nand_to_mtd(chip);
> +	mtd->dev.parent = cdns_ctrl->dev;
> +
> +	/*
> +	 * Default to HW ECC engine mode. If the nand-ecc-mode property is given
> +	 * in the DT node, this entry will be overwritten in nand_scan_ident().
> +	 */
> +	chip->ecc.mode = NAND_ECC_HW;
> +
> +	ret = nand_scan(chip, cdns_chip->nsels);
> +	if (ret) {
> +		dev_err(cdns_ctrl->dev, "could not scan the nand chip\n");
> +		return ret;
> +	}
> +
> +	ret = mtd_device_register(mtd, NULL, 0);
> +	if (ret) {
> +		dev_err(cdns_ctrl->dev,
> +			"failed to register mtd device: %d\n", ret);
> +		nand_cleanup(chip);
> +		return ret;
> +	}
> +
> +	list_add_tail(&cdns_chip->node, &cdns_ctrl->chips);
> +
> +	return 0;
> +}
> +
> +static void cadence_nand_chips_cleanup(struct cdns_nand_ctrl *cdns_ctrl)
> +{
> +	struct cdns_nand_chip *entry, *temp;
> +
> +	list_for_each_entry_safe(entry, temp, &cdns_ctrl->chips, node) {
> +		nand_release(&entry->chip);
> +		list_del(&entry->node);
> +	}
> +}
> +
> +static int cadence_nand_chips_init(struct cdns_nand_ctrl *cdns_ctrl)
> +{
> +	struct device_node *np = cdns_ctrl->dev->of_node;
> +	struct device_node *nand_np;
> +	int max_cs = cdns_ctrl->caps2.max_banks;
> +	int nchips, ret;
> +
> +	nchips = of_get_child_count(np);
> +
> +	if (nchips > max_cs) {
> +		dev_err(cdns_ctrl->dev,
> +			"too many NAND chips: %d (max = %d CS)\n",
> +			nchips, max_cs);
> +		return -EINVAL;
> +	}
> +
> +	for_each_child_of_node(np, nand_np) {
> +		ret = cadence_nand_chip_init(cdns_ctrl, nand_np);
> +		if (ret) {
> +			of_node_put(nand_np);
> +			cadence_nand_chips_cleanup(cdns_ctrl);
> +			return ret;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int cadence_nand_init(struct cdns_nand_ctrl *cdns_ctrl)
> +{
> +	dma_cap_mask_t mask;
> +	int ret;
> +
> +	cdns_ctrl->cdma_desc = dma_alloc_coherent(cdns_ctrl->dev,
> +						  sizeof(*cdns_ctrl->cdma_desc),
> +						  &cdns_ctrl->dma_cdma_desc,
> +						  GFP_KERNEL);
> +	if (!cdns_ctrl->dma_cdma_desc)
> +		return -ENOMEM;
> +
> +	cdns_ctrl->buf_size = SZ_16K;
> +	cdns_ctrl->buf = kmalloc(cdns_ctrl->buf_size, GFP_KERNEL);
> +	if (!cdns_ctrl->buf) {
> +		goto free_buf_desc;
> +		ret = -ENOMEM;
> +	}
> +
> +	if (devm_request_irq(cdns_ctrl->dev, cdns_ctrl->irq, cadence_nand_isr,
> +			     IRQF_SHARED, "cadence-nand-controller",
> +			     cdns_ctrl)) {
> +		dev_err(cdns_ctrl->dev, "Unable to allocate IRQ\n");
> +		ret = -ENODEV;
> +		goto free_buf;
> +	}
> +
> +	spin_lock_init(&cdns_ctrl->irq_lock);
> +	init_completion(&cdns_ctrl->complete);
> +
> +	ret = cadence_nand_hw_init(cdns_ctrl);
> +	if (ret)
> +		goto disable_irq;
> +
> +	dma_cap_zero(mask);
> +	dma_cap_set(DMA_MEMCPY, mask);
> +
> +	if (cdns_ctrl->caps1->has_dma) {
> +		cdns_ctrl->dmac = dma_request_channel(mask, NULL, NULL);
> +		if (!cdns_ctrl->dmac) {
> +			dev_err(cdns_ctrl->dev,
> +				"Unable to get a DMA channel\n");
> +			ret = -EBUSY;
> +			goto disable_irq;
> +		}
> +	}
> +
> +	nand_controller_init(&cdns_ctrl->controller);
> +	INIT_LIST_HEAD(&cdns_ctrl->chips);
> +
> +	cdns_ctrl->controller.ops = &cadence_nand_controller_ops;
> +	cdns_ctrl->curr_corr_str_idx = 0xFF;
> +
> +	ret = cadence_nand_chips_init(cdns_ctrl);
> +	if (ret) {
> +		dev_err(cdns_ctrl->dev, "Failed to register MTD: %d\n",
> +			ret);
> +		goto dma_release_chnl;
> +	}
> +
> +	return 0;
> +
> +dma_release_chnl:
> +	if (cdns_ctrl->dmac)
> +		dma_release_channel(cdns_ctrl->dmac);
> +
> +disable_irq:
> +	cadence_nand_irq_cleanup(cdns_ctrl->irq, cdns_ctrl);
> +
> +free_buf:
> +	kfree(cdns_ctrl->buf);
> +
> +free_buf_desc:
> +	dma_free_coherent(cdns_ctrl->dev, sizeof(struct cadence_nand_cdma_desc),
> +			  cdns_ctrl->cdma_desc, cdns_ctrl->dma_cdma_desc);
> +
> +	return ret;
> +}
> +
> +/* Driver exit point. */
> +static void cadence_nand_remove(struct cdns_nand_ctrl *cdns_ctrl)
> +{
> +	cadence_nand_chips_cleanup(cdns_ctrl);
> +	cadence_nand_irq_cleanup(cdns_ctrl->irq, cdns_ctrl);
> +	kfree(cdns_ctrl->buf);
> +	dma_free_coherent(cdns_ctrl->dev, sizeof(struct cadence_nand_cdma_desc),
> +			  cdns_ctrl->cdma_desc, cdns_ctrl->dma_cdma_desc);
> +
> +	if (cdns_ctrl->dmac)
> +		dma_release_channel(cdns_ctrl->dmac);
> +}
> +
> +struct cadence_nand_dt {
> +	struct cdns_nand_ctrl cdns_ctrl;
> +	struct clk *clk;
> +};
> +
> +static const struct cadence_nand_dt_devdata cadence_nand_default = {
> +	.if_skew = 0,
> +	.has_dma = 1,
> +};
> +
> +static const struct of_device_id cadence_nand_dt_ids[] = {
> +	{
> +		.compatible = "cdns,hp-nfc",
> +		.data = &cadence_nand_default
> +	}, {}
> +};
> +
> +MODULE_DEVICE_TABLE(of, cadence_nand_dt_ids);
> +
> +static int cadence_nand_dt_probe(struct platform_device *ofdev)
> +{
> +	struct resource *res;
> +	struct cadence_nand_dt *dt;
> +	struct cdns_nand_ctrl *cdns_ctrl;
> +	int ret;
> +	const struct of_device_id *of_id;
> +	const struct cadence_nand_dt_devdata *devdata;
> +	u32 val;
> +
> +	of_id = of_match_device(cadence_nand_dt_ids, &ofdev->dev);
> +	if (of_id) {
> +		ofdev->id_entry = of_id->data;
> +		devdata = of_id->data;
> +	} else {
> +		pr_err("Failed to find the right device id.\n");
> +		return -ENOMEM;
> +	}
> +
> +	dt = devm_kzalloc(&ofdev->dev, sizeof(*dt), GFP_KERNEL);
> +	if (!dt)
> +		return -ENOMEM;
> +
> +	cdns_ctrl = &dt->cdns_ctrl;
> +	cdns_ctrl->caps1 = devdata;
> +
> +	cdns_ctrl->dev = &ofdev->dev;
> +	cdns_ctrl->irq = platform_get_irq(ofdev, 0);
> +	if (cdns_ctrl->irq < 0) {
> +		dev_err(&ofdev->dev, "no irq defined\n");
> +		return cdns_ctrl->irq;
> +	}
> +	dev_info(cdns_ctrl->dev, "IRQ: nr %d\n", cdns_ctrl->irq);
> +
> +	res = platform_get_resource(ofdev, IORESOURCE_MEM, 0);
> +	cdns_ctrl->reg = devm_ioremap_resource(cdns_ctrl->dev, res);

I think this will be refused by robots, you have to squash the two
lines into

        cdns_ctrl->reg = devm_platform_ioremap_resource(ofdev, 0);

> +	if (IS_ERR(cdns_ctrl->reg)) {
> +		dev_err(&ofdev->dev, "devm_ioremap_resource res 0 failed\n");
> +		return PTR_ERR(cdns_ctrl->reg);
> +	}
> +
> +	res = platform_get_resource(ofdev, IORESOURCE_MEM, 1);
> +	cdns_ctrl->io.dma = res->start;
> +	cdns_ctrl->io.virt = devm_ioremap_resource(&ofdev->dev, res);
> +	if (IS_ERR(cdns_ctrl->io.virt)) {
> +		dev_err(cdns_ctrl->dev, "devm_ioremap_resource res 1 failed\n");
> +		return PTR_ERR(cdns_ctrl->io.virt);
> +	}
> +
> +	dt->clk = devm_clk_get(cdns_ctrl->dev, "nf_clk");
> +	if (IS_ERR(dt->clk))
> +		return PTR_ERR(dt->clk);
> +
> +	cdns_ctrl->nf_clk_rate = clk_get_rate(dt->clk);
> +
> +	ret = of_property_read_u32(ofdev->dev.of_node,
> +				   "cdns,board-delay-ps", &val);
> +	if (ret) {
> +		dev_warn(cdns_ctrl->dev, "missing cdns,board-delay-ps property\n");

Maybe you could turn this property into an optional one, with a default
value?

> +		val = 0;
> +	}
> +	cdns_ctrl->board_delay = val;
> +
> +	ret = cadence_nand_init(cdns_ctrl);
> +	if (ret)
> +		return ret;
> +
> +	platform_set_drvdata(ofdev, dt);
> +	return 0;
> +}
> +
> +static int cadence_nand_dt_remove(struct platform_device *ofdev)
> +{
> +	struct cadence_nand_dt *dt = platform_get_drvdata(ofdev);
> +
> +	cadence_nand_remove(&dt->cdns_ctrl);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver cadence_nand_dt_driver = {
> +	.probe		= cadence_nand_dt_probe,
> +	.remove		= cadence_nand_dt_remove,
> +	.driver		= {
> +		.name	= "cadence-nand-controller",
> +		.of_match_table = cadence_nand_dt_ids,
> +	},
> +};
> +
> +module_platform_driver(cadence_nand_dt_driver);
> +
> +MODULE_AUTHOR("Piotr Sroka <piotrs@cadence.com>");
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("Driver for Cadence NAND flash controller");
> +

Would you mind adding yourself in MAINTAINERS for this driver (+
bindings)?

Thanks,
Miquèl