Introduction¶

The generic NAND driver supports almost all NAND and AG-AND based chipsand connects them to the Memory Technology Devices (MTD) subsystem ofthe Linux Kernel.

This documentation is provided for developers who want to implementboard drivers or filesystem drivers suitable for NAND devices.

Known Bugs And Assumptions¶

None.

Documentation hints¶

The function and structure docs are autogenerated. Each function andstruct member has a short description which is marked with an [XXX]identifier. The following chapters explain the meaning of thoseidentifiers.

Basic board driver¶

For most boards it will be sufficient to provide just the basicfunctions and fill out some really board dependent members in the nandchip description structure.

static struct mtd_info *board_mtd;static void __iomem *baseaddr;

static struct nand_chip board_chip;static void __iomem *baseaddr;

#define NUM_PARTITIONS 2static struct mtd_partition partition_info[] = {    { .name = "Flash partition 1",      .offset =  0,      .size =    8 * 1024 * 1024 },    { .name = "Flash partition 2",      .offset =  MTDPART_OFS_NEXT,      .size =    MTDPART_SIZ_FULL },};

static void board_hwcontrol(struct mtd_info *mtd, int cmd){    switch(cmd){        case NAND_CTL_SETCLE: /* Set CLE pin high */ break;        case NAND_CTL_CLRCLE: /* Set CLE pin low */ break;        case NAND_CTL_SETALE: /* Set ALE pin high */ break;        case NAND_CTL_CLRALE: /* Set ALE pin low */ break;        case NAND_CTL_SETNCE: /* Set nCE pin low */ break;        case NAND_CTL_CLRNCE: /* Set nCE pin high */ break;    }}

static void board_hwcontrol(struct mtd_info *mtd, int cmd){    struct nand_chip *this = mtd_to_nand(mtd);    switch(cmd){        case NAND_CTL_SETCLE: this->legacy.IO_ADDR_W |= CLE_ADRR_BIT;  break;        case NAND_CTL_CLRCLE: this->legacy.IO_ADDR_W &= ~CLE_ADRR_BIT; break;        case NAND_CTL_SETALE: this->legacy.IO_ADDR_W |= ALE_ADRR_BIT;  break;        case NAND_CTL_CLRALE: this->legacy.IO_ADDR_W &= ~ALE_ADRR_BIT; break;    }}

static int __init board_init (void){    struct nand_chip *this;    int err = 0;    /* Allocate memory for MTD device structure and private data */    this = kzalloc(sizeof(struct nand_chip), GFP_KERNEL);    if (!this) {        printk ("Unable to allocate NAND MTD device structure.\n");        err = -ENOMEM;        goto out;    }    board_mtd = nand_to_mtd(this);    /* map physical address */    baseaddr = ioremap(CHIP_PHYSICAL_ADDRESS, 1024);    if (!baseaddr) {        printk("Ioremap to access NAND chip failed\n");        err = -EIO;        goto out_mtd;    }    /* Set address of NAND IO lines */    this->legacy.IO_ADDR_R = baseaddr;    this->legacy.IO_ADDR_W = baseaddr;    /* Reference hardware control function */    this->hwcontrol = board_hwcontrol;    /* Set command delay time, see datasheet for correct value */    this->legacy.chip_delay = CHIP_DEPENDEND_COMMAND_DELAY;    /* Assign the device ready function, if available */    this->legacy.dev_ready = board_dev_ready;    this->eccmode = NAND_ECC_SOFT;    /* Scan to find existence of the device */    if (nand_scan (this, 1)) {        err = -ENXIO;        goto out_ior;    }    add_mtd_partitions(board_mtd, partition_info, NUM_PARTITIONS);    goto out;out_ior:    iounmap(baseaddr);out_mtd:    kfree (this);out:    return err;}module_init(board_init);

#ifdef MODULEstatic void __exit board_cleanup (void){    /* Unregister device */    WARN_ON(mtd_device_unregister(board_mtd));    /* Release resources */    nand_cleanup(mtd_to_nand(board_mtd));    /* unmap physical address */    iounmap(baseaddr);    /* Free the MTD device structure */    kfree (mtd_to_nand(board_mtd));}module_exit(board_cleanup);#endif

Advanced board driver functions¶

This chapter describes the advanced functionality of the NAND driver.For a list of functions which can be overridden by the board driver seethe documentation of the nand_chip structure.

static void board_select_chip (struct mtd_info *mtd, int chip){    /* Deselect all chips, set all nCE pins high */    GPIO(BOARD_NAND_NCE) |= 0xff;    if (chip >= 0)        GPIO(BOARD_NAND_NCE) &= ~ (1 << chip);}

static void board_select_chip (struct mtd_info *mtd, int chip){    struct nand_chip *this = mtd_to_nand(mtd);    /* Deselect all chips */    this->legacy.IO_ADDR_R &= ~BOARD_NAND_ADDR_MASK;    this->legacy.IO_ADDR_W &= ~BOARD_NAND_ADDR_MASK;    switch (chip) {    case 0:        this->legacy.IO_ADDR_R |= BOARD_NAND_ADDR_CHIP0;        this->legacy.IO_ADDR_W |= BOARD_NAND_ADDR_CHIP0;        break;    ....    case n:        this->legacy.IO_ADDR_R |= BOARD_NAND_ADDR_CHIPn;        this->legacy.IO_ADDR_W |= BOARD_NAND_ADDR_CHIPn;        break;    }}

struct nand_oobinfo {    int useecc;    int eccbytes;    int eccpos[24];    int oobfree[8][2];};

<spare data page 0><ecc result 0>...<ecc result n>...<spare data page n><ecc result 0>...<ecc result n>

Filesystem support¶

The NAND driver provides all necessary functions for a filesystem viathe MTD interface.

Filesystems must be aware of the NAND peculiarities and restrictions.One major restrictions of NAND Flash is, that you cannot write as oftenas you want to a page. The consecutive writes to a page, before erasingit again, are restricted to 1-3 writes, depending on the manufacturersspecifications. This applies similar to the spare area.

Therefore NAND aware filesystems must either write in page size chunksor hold a writebuffer to collect smaller writes until they sum up topagesize. Available NAND aware filesystems: JFFS2, YAFFS.

The spare area usage to store filesystem data is controlled by the sparearea placement functionality which is described in one of the earlierchapters.

Tools¶

The MTD project provides a couple of helpful tools to handle NAND Flash.

• flasherase, flasheraseall: Erase and format FLASH partitions
• nandwrite: write filesystem images to NAND FLASH
• nanddump: dump the contents of a NAND FLASH partitions

These tools are aware of the NAND restrictions. Please use those toolsinstead of complaining about errors which are caused by non NAND awareaccess methods.

Constants¶

This chapter describes the constants which might be relevant for adriver developer.

/* Buswitdh is 16 bit */#define NAND_BUSWIDTH_16    0x00000002/* Device supports partial programming without padding */#define NAND_NO_PADDING     0x00000004/* Chip has cache program function */#define NAND_CACHEPRG       0x00000008/* Chip has copy back function */#define NAND_COPYBACK       0x00000010/* AND Chip which has 4 banks and a confusing page / block * assignment. See Renesas datasheet for further information */#define NAND_IS_AND     0x00000020/* Chip has a array of 4 pages which can be read without * additional ready /busy waits */#define NAND_4PAGE_ARRAY    0x00000040

/* The hw ecc generator provides a syndrome instead a ecc value on read * This can only work if we have the ecc bytes directly behind the * data bytes. Applies for DOC and AG-AND Renesas HW Reed Solomon generators */#define NAND_HWECC_SYNDROME 0x00020000

/* No ECC. Usage is not recommended ! */#define NAND_ECC_NONE       0/* Software ECC 3 byte ECC per 256 Byte data */#define NAND_ECC_SOFT       1/* Hardware ECC 3 byte ECC per 256 Byte data */#define NAND_ECC_HW3_256    2/* Hardware ECC 3 byte ECC per 512 Byte data */#define NAND_ECC_HW3_512    3/* Hardware ECC 6 byte ECC per 512 Byte data */#define NAND_ECC_HW6_512    4/* Hardware ECC 8 byte ECC per 512 Byte data */#define NAND_ECC_HW8_512    6

/* Select the chip by setting nCE to low */#define NAND_CTL_SETNCE     1/* Deselect the chip by setting nCE to high */#define NAND_CTL_CLRNCE     2/* Select the command latch by setting CLE to high */#define NAND_CTL_SETCLE     3/* Deselect the command latch by setting CLE to low */#define NAND_CTL_CLRCLE     4/* Select the address latch by setting ALE to high */#define NAND_CTL_SETALE     5/* Deselect the address latch by setting ALE to low */#define NAND_CTL_CLRALE     6/* Set write protection by setting WP to high. Not used! */#define NAND_CTL_SETWP      7/* Clear write protection by setting WP to low. Not used! */#define NAND_CTL_CLRWP      8

/* Options for the bad block table descriptors *//* The number of bits used per block in the bbt on the device */#define NAND_BBT_NRBITS_MSK 0x0000000F#define NAND_BBT_1BIT       0x00000001#define NAND_BBT_2BIT       0x00000002#define NAND_BBT_4BIT       0x00000004#define NAND_BBT_8BIT       0x00000008/* The bad block table is in the last good block of the device */#define NAND_BBT_LASTBLOCK  0x00000010/* The bbt is at the given page, else we must scan for the bbt */#define NAND_BBT_ABSPAGE    0x00000020/* bbt is stored per chip on multichip devices */#define NAND_BBT_PERCHIP    0x00000080/* bbt has a version counter at offset veroffs */#define NAND_BBT_VERSION    0x00000100/* Create a bbt if none axists */#define NAND_BBT_CREATE     0x00000200/* Write bbt if necessary */#define NAND_BBT_WRITE      0x00001000/* Read and write back block contents when writing bbt */#define NAND_BBT_SAVECONTENT    0x00002000

Structures¶

This chapter contains the autogenerated documentation of the structureswhich are used in the NAND driver and might be relevant for a driverdeveloper. Each struct member has a short description which is markedwith an [XXX] identifier. See the chapter “Documentation hints” for anexplanation.

structnand_parameters¶

NAND generic parameters from the parameter page

Definition

struct nand_parameters {  const char *model;  bool supports_set_get_features;  unsigned long set_feature_list[BITS_TO_LONGS(ONFI_FEATURE_NUMBER)];  unsigned long get_feature_list[BITS_TO_LONGS(ONFI_FEATURE_NUMBER)];  struct onfi_params *onfi;};

Members

model

Model name

supports_set_get_features

The NAND chip supports setting/getting features

set_feature_list

Bitmap of features that can be set

get_feature_list

Bitmap of features that can be get

onfi

ONFI specific parameters

structnand_id¶

NAND id structure

Definition

struct nand_id {  u8 data[NAND_MAX_ID_LEN];  int len;};

Members

data

buffer containing the id bytes.

len

ID length.

structnand_ecc_step_info¶

ECC step information of ECC engine

Definition

struct nand_ecc_step_info {  int stepsize;  const int *strengths;  int nstrengths;};

Members

stepsize

data bytes per ECC step

strengths

array of supported strengths

nstrengths

number of supported strengths

structnand_ecc_caps¶

capability of ECC engine

Definition

struct nand_ecc_caps {  const struct nand_ecc_step_info *stepinfos;  int nstepinfos;  int (*calc_ecc_bytes)(int step_size, int strength);};

Members

stepinfos

array of ECC step information

nstepinfos

number of ECC step information

calc_ecc_bytes

driver’s hook to calculate ECC bytes per step

structnand_ecc_ctrl¶

Control structure for ECC

Definition

struct nand_ecc_ctrl {  enum nand_ecc_mode mode;  enum nand_ecc_algo algo;  int steps;  int size;  int bytes;  int total;  int strength;  int prepad;  int postpad;  unsigned int options;  void *priv;  u8 *calc_buf;  u8 *code_buf;  void (*hwctl)(struct nand_chip *chip, int mode);  int (*calculate)(struct nand_chip *chip, const uint8_t *dat, uint8_t *ecc_code);  int (*correct)(struct nand_chip *chip, uint8_t *dat, uint8_t *read_ecc, uint8_t *calc_ecc);  int (*read_page_raw)(struct nand_chip *chip, uint8_t *buf, int oob_required, int page);  int (*write_page_raw)(struct nand_chip *chip, const uint8_t *buf, int oob_required, int page);  int (*read_page)(struct nand_chip *chip, uint8_t *buf, int oob_required, int page);  int (*read_subpage)(struct nand_chip *chip, uint32_t offs, uint32_t len, uint8_t *buf, int page);  int (*write_subpage)(struct nand_chip *chip, uint32_t offset,uint32_t data_len, const uint8_t *data_buf, int oob_required, int page);  int (*write_page)(struct nand_chip *chip, const uint8_t *buf, int oob_required, int page);  int (*write_oob_raw)(struct nand_chip *chip, int page);  int (*read_oob_raw)(struct nand_chip *chip, int page);  int (*read_oob)(struct nand_chip *chip, int page);  int (*write_oob)(struct nand_chip *chip, int page);};

Members

mode

ECC mode

algo

ECC algorithm

steps

number of ECC steps per page

size

data bytes per ECC step

bytes

ECC bytes per step

total

total number of ECC bytes per page

strength

max number of correctible bits per ECC step

prepad

padding information for syndrome based ECC generators

postpad

padding information for syndrome based ECC generators

options

ECC specific options (see NAND_ECC_XXX flags defined above)

priv

pointer to private ECC control data

calc_buf

buffer for calculated ECC, size is oobsize.

code_buf

buffer for ECC read from flash, size is oobsize.

hwctl

function to control hardware ECC generator. Must onlybe provided if an hardware ECC is available

calculate

function for ECC calculation or readback from ECC hardware

correct

function for ECC correction, matching to ECC generator (sw/hw).Should return a positive number representing the number ofcorrected bitflips, -EBADMSG if the number of bitflips exceedECC strength, or any other error code if the error is notdirectly related to correction.If -EBADMSG is returned the input buffers should be leftuntouched.

read_page_raw

function to read a raw page without ECC. This functionshould hide the specific layout used by the ECCcontroller and always return contiguous in-band andout-of-band data even if they’re not storedcontiguously on the NAND chip (e.g.NAND_ECC_HW_SYNDROME interleaves in-band andout-of-band data).

write_page_raw

function to write a raw page without ECC. This functionshould hide the specific layout used by the ECCcontroller and consider the passed data as contiguousin-band and out-of-band data. ECC controller isresponsible for doing the appropriate transformationsto adapt to its specific layout (e.g.NAND_ECC_HW_SYNDROME interleaves in-band andout-of-band data).

read_page

function to read a page according to the ECC generatorrequirements; returns maximum number of bitflips corrected inany single ECC step, -EIO hw error

read_subpage

function to read parts of the page covered by ECC;returns same as read_page()

write_subpage

function to write parts of the page covered by ECC.

write_page

function to write a page according to the ECC generatorrequirements.

write_oob_raw

function to write chip OOB data without ECC

read_oob_raw

function to read chip OOB data without ECC

read_oob

function to read chip OOB data

write_oob

function to write chip OOB data

structnand_sdr_timings¶

SDR NAND chip timings

Definition

struct nand_sdr_timings {  u64 tBERS_max;  u32 tCCS_min;  u64 tPROG_max;  u64 tR_max;  u32 tALH_min;  u32 tADL_min;  u32 tALS_min;  u32 tAR_min;  u32 tCEA_max;  u32 tCEH_min;  u32 tCH_min;  u32 tCHZ_max;  u32 tCLH_min;  u32 tCLR_min;  u32 tCLS_min;  u32 tCOH_min;  u32 tCS_min;  u32 tDH_min;  u32 tDS_min;  u32 tFEAT_max;  u32 tIR_min;  u32 tITC_max;  u32 tRC_min;  u32 tREA_max;  u32 tREH_min;  u32 tRHOH_min;  u32 tRHW_min;  u32 tRHZ_max;  u32 tRLOH_min;  u32 tRP_min;  u32 tRR_min;  u64 tRST_max;  u32 tWB_max;  u32 tWC_min;  u32 tWH_min;  u32 tWHR_min;  u32 tWP_min;  u32 tWW_min;};

Members

tBERS_max

Block erase time

tCCS_min

Change column setup time

tPROG_max

Page program time

tR_max

Page read time

tALH_min

ALE hold time

tADL_min

ALE to data loading time

tALS_min

ALE setup time

tAR_min

ALE to RE# delay

tCEA_max

CE# access time

tCEH_min

CE# high hold time

tCH_min

CE# hold time

tCHZ_max

CE# high to output hi-Z

tCLH_min

CLE hold time

tCLR_min

CLE to RE# delay

tCLS_min

CLE setup time

tCOH_min

CE# high to output hold

tCS_min

CE# setup time

tDH_min

Data hold time

tDS_min

Data setup time

tFEAT_max

Busy time for Set Features and Get Features

tIR_min

Output hi-Z to RE# low

tITC_max

Interface and Timing Mode Change time

tRC_min

RE# cycle time

tREA_max

RE# access time

tREH_min

RE# high hold time

tRHOH_min

RE# high to output hold

tRHW_min

RE# high to WE# low

tRHZ_max

RE# high to output hi-Z

tRLOH_min

RE# low to output hold

tRP_min

RE# pulse width

tRR_min

Ready to RE# low (data only)

tRST_max

Device reset time, measured from the falling edge of R/B# to therising edge of R/B#.

tWB_max

WE# high to SR[6] low

tWC_min

WE# cycle time

tWH_min

WE# high hold time

tWHR_min

WE# high to RE# low

tWP_min

WE# pulse width

tWW_min

WP# transition to WE# low

Description

This struct defines the timing requirements of a SDR NAND chip.These information can be found in every NAND datasheets and the timingsmeaning are described in the ONFI specifications:www.onfi.org/~/media/ONFI/specs/onfi_3_1_spec.pdf (chapter 4.15 TimingParameters)

All these timings are expressed in picoseconds.

enumnand_data_interface_type¶

NAND interface timing type

Constants

NAND_SDR_IFACE

Single Data Rate interface

structnand_data_interface¶

NAND interface timing

Definition

struct nand_data_interface {  enum nand_data_interface_type type;  struct nand_timings {    unsigned int mode;    union {      struct nand_sdr_timings sdr;    };  } timings;};

Members

type

type of the timing

timings

The timing information

timings.mode

Timing mode as defined in the specification

{unnamed_union}

anonymous

timings.sdr

Use it whentype isNAND_SDR_IFACE.

const structnand_sdr_timings *nand_get_sdr_timings(const structnand_data_interface * conf)¶

get SDR timing from data interface

Parameters

conststructnand_data_interface*conf

The data interface

structnand_op_cmd_instr¶

Definition of a command instruction

Definition

struct nand_op_cmd_instr {  u8 opcode;};

Members

opcode

the command to issue in one cycle

structnand_op_addr_instr¶

Definition of an address instruction

Definition

struct nand_op_addr_instr {  unsigned int naddrs;  const u8 *addrs;};

Members

naddrs

length of theaddrs array

addrs

array containing the address cycles to issue

structnand_op_data_instr¶

Definition of a data instruction

Definition

struct nand_op_data_instr {  unsigned int len;  union {    void *in;    const void *out;  } buf;  bool force_8bit;};

Members

len

number of data bytes to move

buf

buffer to fill

buf.in

buffer to fill when reading from the NAND chip

buf.out

buffer to read from when writing to the NAND chip

force_8bit

force 8-bit access

Description

Please note that “in” and “out” are inverted from the ONFI specificationand are from the controller perspective, so a “in” is a read from the NANDchip while a “out” is a write to the NAND chip.

structnand_op_waitrdy_instr¶

Definition of a wait ready instruction

Definition

struct nand_op_waitrdy_instr {  unsigned int timeout_ms;};

Members

timeout_ms

maximum delay while waiting for the ready/busy pin in ms

enumnand_op_instr_type¶

Definition of all instruction types

Constants

NAND_OP_CMD_INSTR

command instruction

NAND_OP_ADDR_INSTR

address instruction

NAND_OP_DATA_IN_INSTR

data in instruction

NAND_OP_DATA_OUT_INSTR

data out instruction

NAND_OP_WAITRDY_INSTR

wait ready instruction

structnand_op_instr¶

Instruction object

Definition

struct nand_op_instr {  enum nand_op_instr_type type;  union {    struct nand_op_cmd_instr cmd;    struct nand_op_addr_instr addr;    struct nand_op_data_instr data;    struct nand_op_waitrdy_instr waitrdy;  } ctx;  unsigned int delay_ns;};

Members

type

the instruction type

ctx

extra data associated to the instruction. You’ll have to use theappropriate element depending ontype

ctx.cmd

use it iftype isNAND_OP_CMD_INSTR

ctx.addr

use it iftype isNAND_OP_ADDR_INSTR

ctx.data

use it iftype isNAND_OP_DATA_IN_INSTRorNAND_OP_DATA_OUT_INSTR

ctx.waitrdy

use it iftype isNAND_OP_WAITRDY_INSTR

delay_ns

delay the controller should apply after the instruction has beenissued on the bus. Most modern controllers have internal timingscontrol logic, and in this case, the controller driver can ignorethis field.

structnand_subop¶

a sub operation

Definition

struct nand_subop {  unsigned int cs;  const struct nand_op_instr *instrs;  unsigned int ninstrs;  unsigned int first_instr_start_off;  unsigned int last_instr_end_off;};

Members

cs

the CS line to select for this NAND sub-operation

instrs

array of instructions

ninstrs

length of theinstrs array

first_instr_start_off

offset to start from for the first instructionof the sub-operation

last_instr_end_off

offset to end at (excluded) for the last instructionof the sub-operation

Description

Bothfirst_instr_start_off andlast_instr_end_off only apply to data oraddress instructions.

When an operation cannot be handled as is by the NAND controller, it willbe split by the parser into sub-operations which will be passed to thecontroller driver.

structnand_op_parser_addr_constraints¶

Constraints for address instructions

Definition

struct nand_op_parser_addr_constraints {  unsigned int maxcycles;};

Members

maxcycles

maximum number of address cycles the controller can issue in asingle step

structnand_op_parser_data_constraints¶

Constraints for data instructions

Definition

struct nand_op_parser_data_constraints {  unsigned int maxlen;};

Members

maxlen

maximum data length that the controller can handle in a single step

structnand_op_parser_pattern_elem¶

One element of a pattern

Definition

struct nand_op_parser_pattern_elem {  enum nand_op_instr_type type;  bool optional;  union {    struct nand_op_parser_addr_constraints addr;    struct nand_op_parser_data_constraints data;  } ctx;};

Members

type

the instructuction type

optional

whether this element of the pattern is optional or mandatory

ctx

address or data constraint

ctx.addr

address constraint (number of cycles)

ctx.data

data constraint (data length)

structnand_op_parser_pattern¶

NAND sub-operation pattern descriptor

Definition

struct nand_op_parser_pattern {  const struct nand_op_parser_pattern_elem *elems;  unsigned int nelems;  int (*exec)(struct nand_chip *chip, const struct nand_subop *subop);};

Members

elems

array of pattern elements

nelems

number of pattern elements inelems array

exec

the function that will issue a sub-operation

Description

A pattern is a list of elements, each element reprensenting one instructionwith its constraints. The pattern itself is used by the core to match NANDchip operation with NAND controller operations.Once a match between a NAND controller operation pattern and a NAND chipoperation (or a sub-set of a NAND operation) is found, the pattern ->exec()hook is called so that the controller driver can issue the operation on thebus.

Controller drivers should declare as many patterns as they support and passthis list of patterns (created with the help of the following macro) tothenand_op_parser_exec_op() helper.

structnand_op_parser¶

NAND controller operation parser descriptor

Definition

struct nand_op_parser {  const struct nand_op_parser_pattern *patterns;  unsigned int npatterns;};

Members

patterns

array of supported patterns

npatterns

length of thepatterns array

Description

The parser descriptor is just an array of supported patterns which will beiterated bynand_op_parser_exec_op() everytime it tries to execute anNAND operation (or tries to determine if a specific operation is supported).

It is worth mentioning that patterns will be tested in their declarationorder, and the first match will be taken, so it’s important to order patternsappropriately so that simple/inefficient patterns are placed at the end ofthe list. Usually, this is where you put single instruction patterns.

structnand_operation¶

NAND operation descriptor

Definition

struct nand_operation {  unsigned int cs;  const struct nand_op_instr *instrs;  unsigned int ninstrs;};

Members

cs

the CS line to select for this NAND operation

instrs

array of instructions to execute

ninstrs

length of theinstrs array

Description

The actual operation structure that will be passed to chip->exec_op().

structnand_controller_ops¶

Controller operations

Definition

struct nand_controller_ops {  int (*attach_chip)(struct nand_chip *chip);  void (*detach_chip)(struct nand_chip *chip);  int (*exec_op)(struct nand_chip *chip,const struct nand_operation *op, bool check_only);  int (*setup_data_interface)(struct nand_chip *chip, int chipnr, const struct nand_data_interface *conf);};

Members

attach_chip

this method is called after the NAND detection phase afterflash ID and MTD fields such as erase size, page size and OOBsize have been set up. ECC requirements are available ifprovided by the NAND chip or device tree. Typically used tochoose the appropriate ECC configuration and allocateassociated resources.This hook is optional.

detach_chip

free all resources allocated/claimed innand_controller_ops->attach_chip().This hook is optional.

exec_op

controller specific method to execute NAND operations.This method replaces chip->legacy.cmdfunc(),chip->legacy.{read,write}_{buf,byte,word}(),chip->legacy.dev_ready() and chip->legacy.waifunc().

setup_data_interface

setup the data interface and timing. Ifchipnr is set toNAND_DATA_IFACE_CHECK_ONLY thismeans the configuration should not be applied butonly checked.This hook is optional.

structnand_controller¶

Structure used to describe a NAND controller

Definition

struct nand_controller {  struct mutex lock;  const struct nand_controller_ops *ops;};

Members

lock

lock used to serialize accesses to the NAND controller

ops

NAND controller operations.

structnand_legacy¶

NAND chip legacy fields/hooks

Definition

struct nand_legacy {  void __iomem *IO_ADDR_R;  void __iomem *IO_ADDR_W;  void (*select_chip)(struct nand_chip *chip, int cs);  u8 (*read_byte)(struct nand_chip *chip);  void (*write_byte)(struct nand_chip *chip, u8 byte);  void (*write_buf)(struct nand_chip *chip, const u8 *buf, int len);  void (*read_buf)(struct nand_chip *chip, u8 *buf, int len);  void (*cmd_ctrl)(struct nand_chip *chip, int dat, unsigned int ctrl);  void (*cmdfunc)(struct nand_chip *chip, unsigned command, int column, int page_addr);  int (*dev_ready)(struct nand_chip *chip);  int (*waitfunc)(struct nand_chip *chip);  int (*block_bad)(struct nand_chip *chip, loff_t ofs);  int (*block_markbad)(struct nand_chip *chip, loff_t ofs);  int (*set_features)(struct nand_chip *chip, int feature_addr, u8 *subfeature_para);  int (*get_features)(struct nand_chip *chip, int feature_addr, u8 *subfeature_para);  int chip_delay;  struct nand_controller dummy_controller;};

Members

IO_ADDR_R

address to read the 8 I/O lines of the flash device

IO_ADDR_W

address to write the 8 I/O lines of the flash device

select_chip

select/deselect a specific target/die

read_byte

read one byte from the chip

write_byte

write a single byte to the chip on the low 8 I/O lines

write_buf

write data from the buffer to the chip

read_buf

read data from the chip into the buffer

cmd_ctrl

hardware specific function for controlling ALE/CLE/nCE. Also usedto write command and address

cmdfunc

hardware specific function for writing commands to the chip.

dev_ready

hardware specific function for accessing device ready/busy line.If set to NULL no access to ready/busy is available and theready/busy information is read from the chip status register.

waitfunc

hardware specific function for wait on ready.

block_bad

check if a block is bad, using OOB markers

block_markbad

mark a block bad

set_features

set the NAND chip features

get_features

get the NAND chip features

chip_delay

chip dependent delay for transferring data from array to readregs (tR).

dummy_controller

dummy controller implementation for drivers that canonly control a single chip

Description

If you look at this structure you’re already wrong. These fields/hooks areall deprecated.

structnand_chip¶

NAND Private Flash Chip Data

Definition

struct nand_chip {  struct nand_device base;  struct nand_legacy legacy;  int (*setup_read_retry)(struct nand_chip *chip, int retry_mode);  unsigned int options;  unsigned int bbt_options;  int page_shift;  int phys_erase_shift;  int bbt_erase_shift;  int chip_shift;  int pagemask;  u8 *data_buf;  struct {    unsigned int bitflips;    int page;  } pagecache;  int subpagesize;  int onfi_timing_mode_default;  unsigned int badblockpos;  int badblockbits;  struct nand_id id;  struct nand_parameters parameters;  struct nand_data_interface data_interface;  int cur_cs;  int read_retries;  struct mutex lock;  unsigned int suspended : 1;  int (*suspend)(struct nand_chip *chip);  void (*resume)(struct nand_chip *chip);  uint8_t *oob_poi;  struct nand_controller *controller;  struct nand_ecc_ctrl ecc;  unsigned long buf_align;  uint8_t *bbt;  struct nand_bbt_descr *bbt_td;  struct nand_bbt_descr *bbt_md;  struct nand_bbt_descr *badblock_pattern;  void *priv;  struct {    const struct nand_manufacturer *desc;    void *priv;  } manufacturer;  int (*lock_area)(struct nand_chip *chip, loff_t ofs, uint64_t len);  int (*unlock_area)(struct nand_chip *chip, loff_t ofs, uint64_t len);};

Members

base

Inherit from the generic NAND device

legacy

All legacy fields/hooks. If you develop a new driver,don’t even try to use any of these fields/hooks, and ifyou’re modifying an existing driver that is using thosefields/hooks, you should consider reworking the driveravoid using them.

setup_read_retry

[FLASHSPECIFIC] flash (vendor) specific function forsetting the read-retry mode. Mostly needed for MLC NAND.

options

[BOARDSPECIFIC] various chip options. They can partlybe set to inform nand_scan about special functionality.See the defines for further explanation.

bbt_options

[INTERN] bad block specific options. All options usedhere must come from bbm.h. By default, these optionswill be copied to the appropriate nand_bbt_descr’s.

page_shift

[INTERN] number of address bits in a page (columnaddress bits).

phys_erase_shift

[INTERN] number of address bits in a physical eraseblock

bbt_erase_shift

[INTERN] number of address bits in a bbt entry

chip_shift

[INTERN] number of address bits in one chip

pagemask

[INTERN] page number mask = number of (pages / chip) - 1

data_buf

[INTERN] buffer for data, size is (page size + oobsize).

pagecache

Structure containing page cache related fields

pagecache.bitflips

Number of bitflips of the cached page

pagecache.page

Page number currently in the cache. -1 means no page iscurrently cached

subpagesize

[INTERN] holds the subpagesize

onfi_timing_mode_default

[INTERN] default ONFI timing mode. This field isset to the actually used ONFI mode if the chip isONFI compliant or deduced from the datasheet ifthe NAND chip is not ONFI compliant.

badblockpos

[INTERN] position of the bad block marker in the oobarea.

badblockbits

[INTERN] minimum number of set bits in a good block’sbad block marker position; i.e., BBM == 11110111b isnot bad when badblockbits == 7

id

[INTERN] holds NAND ID

parameters

[INTERN] holds generic parameters under an easilyreadable form.

data_interface

[INTERN] NAND interface timing information

cur_cs

currently selected target. -1 means no target selected,otherwise we should always have cur_cs >= 0 &&cur_cs < nanddev_ntargets(). NAND Controller driversshould not modify this value, but they’re allowed toread it.

read_retries

[INTERN] the number of read retry modes supported

lock

lock protecting the suspended field. Also used toserialize accesses to the NAND device.

suspended

set to 1 when the device is suspended, 0 when it’s not.

suspend

[REPLACEABLE] specific NAND device suspend operation

resume

[REPLACEABLE] specific NAND device resume operation

oob_poi

“poison value buffer,” used for laying out OOB databefore writing

controller

[REPLACEABLE] a pointer to a hardware controllerstructure which is shared among multiple independentdevices.

ecc

[BOARDSPECIFIC] ECC control structure

buf_align

minimum buffer alignment required by a platform

bbt

[INTERN] bad block table pointer

bbt_td

[REPLACEABLE] bad block table descriptor for flashlookup.

bbt_md

[REPLACEABLE] bad block table mirror descriptor

badblock_pattern

[REPLACEABLE] bad block scan pattern used for initialbad block scan.

priv

[OPTIONAL] pointer to private chip data

manufacturer

[INTERN] Contains manufacturer information

manufacturer.desc

[INTERN] Contains manufacturer’s description

manufacturer.priv

[INTERN] Contains manufacturer private information

lock_area

[REPLACEABLE] specific NAND chip lock operation

unlock_area

[REPLACEABLE] specific NAND chip unlock operation

structnand_flash_dev¶

NAND Flash Device ID Structure

Definition

struct nand_flash_dev {  char *name;  union {    struct {      uint8_t mfr_id;      uint8_t dev_id;    };    uint8_t id[NAND_MAX_ID_LEN];  };  unsigned int pagesize;  unsigned int chipsize;  unsigned int erasesize;  unsigned int options;  uint16_t id_len;  uint16_t oobsize;  struct {    uint16_t strength_ds;    uint16_t step_ds;  } ecc;  int onfi_timing_mode_default;};

Members

name

a human-readable name of the NAND chip

{unnamed_union}

anonymous

{unnamed_struct}

anonymous

mfr_id

manufacturer ID part of the full chip ID array (refers the samememory address asid[0])

dev_id

device ID part of the full chip ID array (refers the same memoryaddress asid[1])

id

full device ID array

pagesize

size of the NAND page in bytes; if 0, then the real page size (aswell as the eraseblock size) is determined from the extended NANDchip ID array)

chipsize

total chip size in MiB

erasesize

eraseblock size in bytes (determined from the extended ID if 0)

options

stores various chip bit options

id_len

The valid length of theid.

oobsize

OOB size

ecc

ECC correctability and step information from the datasheet.

ecc.strength_ds

The ECC correctability from the datasheet, same as theecc_strength_ds in nand_chip{}.

ecc.step_ds

The ECC step required by theecc.strength_ds, same as theecc_step_ds in nand_chip{}, also from the datasheet.For example, the “4bit ECC for each 512Byte” can be set withNAND_ECC_INFO(4, 512).

onfi_timing_mode_default

the default ONFI timing mode entered after a NANDreset. Should be deduced from timings describedin the datasheet.

intnand_opcode_8bits(unsigned int command)¶

Parameters

unsignedintcommand

opcode to check

void *nand_get_data_buf(structnand_chip * chip)¶

Get the internal page buffer

Parameters

structnand_chip*chip

NAND chip object

Description

Returns the pre-allocated page buffer after invalidating the cache. Thisfunction should be used by drivers that do not want to allocate their ownbounce buffer and still need such a buffer for specific operations (mostcommonly when reading OOB data only).

Be careful to never call this function in the write/write_oob path, becausethe core may have placed the data to be written out in this buffer.

Return

pointer to the page cache buffer

Public Functions Provided¶

This chapter contains the autogenerated documentation of the NAND kernelAPI functions which are exported. Each function has a short descriptionwhich is marked with an [XXX] identifier. See the chapter “Documentationhints” for an explanation.

voidnand_extract_bits(u8 * dst, unsigned int dst_off, const u8 * src, unsigned int src_off, unsigned int nbits)¶

Copy unaligned bits from one buffer to another one

Parameters

u8*dst

destination buffer

unsignedintdst_off

bit offset at which the writing starts

constu8*src

source buffer

unsignedintsrc_off

bit offset at which the reading starts

unsignedintnbits

number of bits to copy fromsrc todst

Description

Copy bits from one memory region to another (overlap authorized).

voidnand_select_target(structnand_chip * chip, unsigned int cs)¶

Select a NAND target (A.K.A. die)

Parameters

structnand_chip*chip

NAND chip object

unsignedintcs

the CS line to select. Note that this CS id is always from the chipPoV, not the controller one

Description

Select a NAND target so that further operations executed onchip go to theselected NAND target.

voidnand_deselect_target(structnand_chip * chip)¶

Deselect the currently selected target

Parameters

structnand_chip*chip

NAND chip object

Description

Deselect the currently selected NAND target. The result of operationsexecuted onchip after the target has been deselected is undefined.

intnand_soft_waitrdy(structnand_chip * chip, unsigned long timeout_ms)¶

Poll STATUS reg until RDY bit is set to 1

Parameters

structnand_chip*chip

NAND chip structure

unsignedlongtimeout_ms

Timeout in ms

Description

Poll the STATUS register using ->exec_op() until the RDY bit becomes 1.If that does not happen whitin the specified timeout, -ETIMEDOUT isreturned.

This helper is intended to be used when the controller does not have accessto the NAND R/B pin.

Be aware that calling this helper from an ->exec_op() implementation means->exec_op() must be re-entrant.

Return 0 if the NAND chip is ready, a negative error otherwise.

intnand_gpio_waitrdy(structnand_chip * chip, struct gpio_desc * gpiod, unsigned long timeout_ms)¶

Poll R/B GPIO pin until ready

Parameters

structnand_chip*chip

NAND chip structure

structgpio_desc*gpiod

GPIO descriptor of R/B pin

unsignedlongtimeout_ms

Timeout in ms

Description

Poll the R/B GPIO pin until it becomes ready. If that does not happenwhitin the specified timeout, -ETIMEDOUT is returned.

This helper is intended to be used when the controller has access to theNAND R/B pin over GPIO.

Return 0 if the R/B pin indicates chip is ready, a negative error otherwise.

intnand_read_page_op(structnand_chip * chip, unsigned int page, unsigned int offset_in_page, void * buf, unsigned int len)¶

Do a READ PAGE operation

Parameters

structnand_chip*chip

The NAND chip

unsignedintpage

page to read

unsignedintoffset_in_page

offset within the page

void*buf

buffer used to store the data

unsignedintlen

length of the buffer

Description

This function issues a READ PAGE operation.This function does not select/unselect the CS line.

Returns 0 on success, a negative error code otherwise.

intnand_change_read_column_op(structnand_chip * chip, unsigned int offset_in_page, void * buf, unsigned int len, bool force_8bit)¶

Do a CHANGE READ COLUMN operation

Parameters

structnand_chip*chip

The NAND chip

unsignedintoffset_in_page

offset within the page

void*buf

buffer used to store the data

unsignedintlen

length of the buffer

boolforce_8bit

force 8-bit bus access

Description

This function issues a CHANGE READ COLUMN operation.This function does not select/unselect the CS line.

Returns 0 on success, a negative error code otherwise.

intnand_read_oob_op(structnand_chip * chip, unsigned int page, unsigned int offset_in_oob, void * buf, unsigned int len)¶

Do a READ OOB operation

Parameters

structnand_chip*chip

The NAND chip

unsignedintpage

page to read

unsignedintoffset_in_oob

offset within the OOB area

void*buf

buffer used to store the data

unsignedintlen

length of the buffer

Description

This function issues a READ OOB operation.This function does not select/unselect the CS line.

Returns 0 on success, a negative error code otherwise.

intnand_prog_page_begin_op(structnand_chip * chip, unsigned int page, unsigned int offset_in_page, const void * buf, unsigned int len)¶

starts a PROG PAGE operation

Parameters

structnand_chip*chip

The NAND chip

unsignedintpage

page to write

unsignedintoffset_in_page

offset within the page

constvoid*buf

buffer containing the data to write to the page

unsignedintlen

length of the buffer

Description

This function issues the first half of a PROG PAGE operation.This function does not select/unselect the CS line.

Returns 0 on success, a negative error code otherwise.

intnand_prog_page_end_op(structnand_chip * chip)¶

ends a PROG PAGE operation

Parameters

structnand_chip*chip

The NAND chip

Description

This function issues the second half of a PROG PAGE operation.This function does not select/unselect the CS line.

Returns 0 on success, a negative error code otherwise.

intnand_prog_page_op(structnand_chip * chip, unsigned int page, unsigned int offset_in_page, const void * buf, unsigned int len)¶

Do a full PROG PAGE operation

Parameters

structnand_chip*chip

The NAND chip

unsignedintpage

page to write

unsignedintoffset_in_page

offset within the page

constvoid*buf

buffer containing the data to write to the page

unsignedintlen

length of the buffer

Description

This function issues a full PROG PAGE operation.This function does not select/unselect the CS line.

Returns 0 on success, a negative error code otherwise.

intnand_change_write_column_op(structnand_chip * chip, unsigned int offset_in_page, const void * buf, unsigned int len, bool force_8bit)¶

Do a CHANGE WRITE COLUMN operation

Parameters

structnand_chip*chip

The NAND chip

unsignedintoffset_in_page

offset within the page

constvoid*buf

buffer containing the data to send to the NAND

unsignedintlen

length of the buffer

boolforce_8bit

force 8-bit bus access

Description

This function issues a CHANGE WRITE COLUMN operation.This function does not select/unselect the CS line.

Returns 0 on success, a negative error code otherwise.

intnand_readid_op(structnand_chip * chip, u8 addr, void * buf, unsigned int len)¶

Do a READID operation

Parameters

structnand_chip*chip

The NAND chip

u8addr

address cycle to pass after the READID command

void*buf

buffer used to store the ID

unsignedintlen

length of the buffer

Description

This function sends a READID command and reads back the ID returned by theNAND.This function does not select/unselect the CS line.

Returns 0 on success, a negative error code otherwise.

intnand_status_op(structnand_chip * chip, u8 * status)¶

Do a STATUS operation

Parameters

structnand_chip*chip

The NAND chip

u8*status

out variable to store the NAND status

Description

This function sends a STATUS command and reads back the status returned bythe NAND.This function does not select/unselect the CS line.

Returns 0 on success, a negative error code otherwise.

intnand_erase_op(structnand_chip * chip, unsigned int eraseblock)¶

Do an erase operation

Parameters

structnand_chip*chip

The NAND chip

unsignedinteraseblock

block to erase

Description

This function sends an ERASE command and waits for the NAND to be readybefore returning.This function does not select/unselect the CS line.

Returns 0 on success, a negative error code otherwise.

intnand_reset_op(structnand_chip * chip)¶

Do a reset operation

Parameters

structnand_chip*chip

The NAND chip

Description

This function sends a RESET command and waits for the NAND to be readybefore returning.This function does not select/unselect the CS line.

Returns 0 on success, a negative error code otherwise.

intnand_read_data_op(structnand_chip * chip, void * buf, unsigned int len, bool force_8bit, bool check_only)¶

Read data from the NAND

Parameters

structnand_chip*chip

The NAND chip

void*buf

buffer used to store the data

unsignedintlen

length of the buffer

boolforce_8bit

force 8-bit bus access

boolcheck_only

do not actually run the command, only checks if thecontroller driver supports it

Description

This function does a raw data read on the bus. Usually used after launchinganother NAND operation likenand_read_page_op().This function does not select/unselect the CS line.

Returns 0 on success, a negative error code otherwise.

intnand_write_data_op(structnand_chip * chip, const void * buf, unsigned int len, bool force_8bit)¶

Write data from the NAND

Parameters

structnand_chip*chip

The NAND chip

constvoid*buf

buffer containing the data to send on the bus

unsignedintlen

length of the buffer

boolforce_8bit

force 8-bit bus access

Description

This function does a raw data write on the bus. Usually used after launchinganother NAND operation like nand_write_page_begin_op().This function does not select/unselect the CS line.

Returns 0 on success, a negative error code otherwise.

intnand_op_parser_exec_op(structnand_chip * chip, const structnand_op_parser * parser, const structnand_operation * op, bool check_only)¶

exec_op parser

Parameters

structnand_chip*chip

the NAND chip

conststructnand_op_parser*parser

patterns description provided by the controller driver

conststructnand_operation*op

the NAND operation to address

boolcheck_only

when true, the function only checks ifop can be handled butdoes not execute the operation

Description

Helper function designed to ease integration of NAND controller drivers thatonly support a limited set of instruction sequences. The supported sequencesare described inparser, and the framework takes care of splittingop intomultiple sub-operations (if required) and pass them back to the ->exec()callback of the matching pattern ifcheck_only is set to false.

NAND controller drivers should call this function from their own ->exec_op()implementation.

Returns 0 on success, a negative error code otherwise. A failure can becaused by an unsupported operation (none of the supported patterns is ableto handle the requested operation), or an error returned by one of thematching pattern->exec() hook.

unsigned intnand_subop_get_addr_start_off(const structnand_subop * subop, unsigned int instr_idx)¶

Get the start offset in an address array

Parameters

conststructnand_subop*subop

The entire sub-operation

unsignedintinstr_idx

Index of the instruction inside the sub-operation

Description

During driver development, one could be tempted to directly use the->addr.addrs field of address instructions. This is wrong as addressinstructions might be split.

Given an address instruction, returns the offset of the first cycle to issue.

unsigned intnand_subop_get_num_addr_cyc(const structnand_subop * subop, unsigned int instr_idx)¶

Get the remaining address cycles to assert

Parameters

conststructnand_subop*subop

The entire sub-operation

unsignedintinstr_idx

Index of the instruction inside the sub-operation

Description

During driver development, one could be tempted to directly use the->addr->naddrs field of a data instruction. This is wrong as instructionsmight be split.

Given an address instruction, returns the number of address cycle to issue.

unsigned intnand_subop_get_data_start_off(const structnand_subop * subop, unsigned int instr_idx)¶

Get the start offset in a data array

Parameters

conststructnand_subop*subop

The entire sub-operation

unsignedintinstr_idx

Index of the instruction inside the sub-operation

Description

During driver development, one could be tempted to directly use the->data->buf.{in,out} field of data instructions. This is wrong as datainstructions might be split.

Given a data instruction, returns the offset to start from.

unsigned intnand_subop_get_data_len(const structnand_subop * subop, unsigned int instr_idx)¶

Get the number of bytes to retrieve

Parameters

conststructnand_subop*subop

The entire sub-operation

unsignedintinstr_idx

Index of the instruction inside the sub-operation

Description

During driver development, one could be tempted to directly use the->data->len field of a data instruction. This is wrong as data instructionsmight be split.

Returns the length of the chunk of data to send/receive.

intnand_reset(structnand_chip * chip, int chipnr)¶

Reset and initialize a NAND device

Parameters

structnand_chip*chip

The NAND chip

intchipnr

Internal die id

Description

Save the timings data structure, then apply SDR timings mode 0 (seenand_reset_data_interface for details), do the reset operation, andapply back the previous timings.

Returns 0 on success, a negative error code otherwise.

intnand_check_erased_ecc_chunk(void * data, int datalen, void * ecc, int ecclen, void * extraoob, int extraooblen, int bitflips_threshold)¶

check if an ECC chunk contains (almost) only 0xff data

Parameters

void*data

data buffer to test

intdatalen

data length

void*ecc

ECC buffer

intecclen

ECC length

void*extraoob

extra OOB buffer

intextraooblen

extra OOB length

intbitflips_threshold

maximum number of bitflips

Description

Check if a data buffer and its associated ECC and OOB data contains only0xff pattern, which means the underlying region has been erased and isready to be programmed.The bitflips_threshold specify the maximum number of bitflips beforeconsidering the region as not erased.

Returns a positive number of bitflips less than or equal tobitflips_threshold, or -ERROR_CODE for bitflips in excess of thethreshold. In case of success, the passed buffers are filled with 0xff.

Note

1/ ECC algorithms are working on pre-defined block sizes which are usually

different from the NAND page size. When fixing bitflips, ECC engines willreport the number of errors per chunk, and the NAND core infrastructureexpect you to return the maximum number of bitflips for the whole page.This is why you should always use this function on a single chunk andnot on the whole page. After checking each chunk you should update yourmax_bitflips value accordingly.

2/ When checking for bitflips in erased pages you should not only check

the payload data but also their associated ECC data, because a user mighthave programmed almost all bits to 1 but a few. In this case, weshouldn’t consider the chunk as erased, and checking ECC bytes preventthis case.

3/ The extraoob argument is optional, and should be used if some of your OOB

data are protected by the ECC engine.It could also be used if you support subpages and want to attach someextra OOB data to an ECC chunk.

intnand_read_page_raw(structnand_chip * chip, uint8_t * buf, int oob_required, int page)¶

[INTERN] read raw page data without ecc

Parameters

structnand_chip*chip

nand chip info structure

uint8_t*buf

buffer to store read data

intoob_required

caller requires OOB data read to chip->oob_poi

intpage

page number to read

Description

Not for syndrome calculating ECC controllers, which use a special oob layout.

intnand_monolithic_read_page_raw(structnand_chip * chip, u8 * buf, int oob_required, int page)¶

Monolithic page read in raw mode

Parameters

structnand_chip*chip

NAND chip info structure

u8*buf

buffer to store read data

intoob_required

caller requires OOB data read to chip->oob_poi

intpage

page number to read

Description

This is a raw page read, ie. without any error detection/correction.Monolithic means we are requesting all the relevant data (main pluseventually OOB) to be loaded in the NAND cache and sent over thebus (from the NAND chip to the NAND controller) in a singleoperation. This is an alternative tonand_read_page_raw(), whichfirst reads the main data, and if the OOB data is requested too,then reads more data on the bus.

intnand_read_oob_std(structnand_chip * chip, int page)¶

[REPLACEABLE] the most common OOB data read function

Parameters

structnand_chip*chip

nand chip info structure

intpage

page number to read

intnand_write_oob_std(structnand_chip * chip, int page)¶

[REPLACEABLE] the most common OOB data write function

Parameters

structnand_chip*chip

nand chip info structure

intpage

page number to write

intnand_write_page_raw(structnand_chip * chip, const uint8_t * buf, int oob_required, int page)¶

[INTERN] raw page write function

Parameters

structnand_chip*chip

nand chip info structure

constuint8_t*buf

data buffer

intoob_required

must write chip->oob_poi to OOB

intpage

page number to write

Description

Not for syndrome calculating ECC controllers, which use a special oob layout.

intnand_monolithic_write_page_raw(structnand_chip * chip, const u8 * buf, int oob_required, int page)¶

Monolithic page write in raw mode

Parameters

structnand_chip*chip

NAND chip info structure

constu8*buf

data buffer to write

intoob_required

must write chip->oob_poi to OOB

intpage

page number to write

Description

This is a raw page write, ie. without any error detection/correction.Monolithic means we are requesting all the relevant data (main pluseventually OOB) to be sent over the bus and effectively programmedinto the NAND chip arrays in a single operation. This is analternative tonand_write_page_raw(), which first sends the maindata, then eventually send the OOB data by latching more datacycles on the NAND bus, and finally sends the program command tosynchronyze the NAND chip cache.

intnand_ecc_choose_conf(structnand_chip * chip, const structnand_ecc_caps * caps, int oobavail)¶

Set the ECC strength and ECC step size

Parameters

structnand_chip*chip

nand chip info structure

conststructnand_ecc_caps*caps

ECC engine caps info structure

intoobavail

OOB size that the ECC engine can use

Description

Choose the ECC configuration according to following logic

1. If both ECC step size and ECC strength are already set (usually by DT)then check if it is supported by this controller.
2. If NAND_ECC_MAXIMIZE is set, then select maximum ECC strength.
3. Otherwise, try to match the ECC step size and ECC strength closestto the chip’s requirement. If available OOB size can’t fit the chiprequirement then fallback to the maximum ECC step size and ECC strength.

On success, the chosen ECC settings are set.

intnand_scan_with_ids(structnand_chip * chip, unsigned int maxchips, structnand_flash_dev * ids)¶

[NAND Interface] Scan for the NAND device

Parameters

structnand_chip*chip

NAND chip object

unsignedintmaxchips

number of chips to scan for.

structnand_flash_dev*ids

optional flash IDs table

Description

This fills out all the uninitialized function pointers with the defaults.The flash ID is read and the mtd/chip structures are filled with theappropriate values.

voidnand_cleanup(structnand_chip * chip)¶

[NAND Interface] Free resources held by the NAND device

Parameters

structnand_chip*chip

NAND chip object

void__nand_calculate_ecc(const unsigned char * buf, unsigned int eccsize, unsigned char * code, bool sm_order)¶

[NAND Interface] Calculate 3-byte ECC for 256/512-byte block

Parameters

constunsignedchar*buf

input buffer with raw data

unsignedinteccsize

data bytes per ECC step (256 or 512)

unsignedchar*code

output buffer with ECC

boolsm_order

Smart Media byte ordering

intnand_calculate_ecc(structnand_chip * chip, const unsigned char * buf, unsigned char * code)¶

[NAND Interface] Calculate 3-byte ECC for 256/512-byte block

Parameters

structnand_chip*chip

NAND chip object

constunsignedchar*buf

input buffer with raw data

unsignedchar*code

output buffer with ECC

int__nand_correct_data(unsigned char * buf, unsigned char * read_ecc, unsigned char * calc_ecc, unsigned int eccsize, bool sm_order)¶

[NAND Interface] Detect and correct bit error(s)

Parameters

unsignedchar*buf

raw data read from the chip

unsignedchar*read_ecc

ECC from the chip

unsignedchar*calc_ecc

the ECC calculated from raw data

unsignedinteccsize

data bytes per ECC step (256 or 512)

boolsm_order

Smart Media byte order

Description

Detect and correct a 1 bit error for eccsize byte block

intnand_correct_data(structnand_chip * chip, unsigned char * buf, unsigned char * read_ecc, unsigned char * calc_ecc)¶

[NAND Interface] Detect and correct bit error(s)

Parameters

structnand_chip*chip

NAND chip object

unsignedchar*buf

raw data read from the chip

unsignedchar*read_ecc

ECC from the chip

unsignedchar*calc_ecc

the ECC calculated from raw data

Description

Detect and correct a 1 bit error for 256/512 byte block

Internal Functions Provided¶

This chapter contains the autogenerated documentation of the NAND driverinternal functions. Each function has a short description which ismarked with an [XXX] identifier. See the chapter “Documentation hints”for an explanation. The functions marked with [DEFAULT] might berelevant for a board driver developer.

voidnand_release_device(structnand_chip * chip)¶

[GENERIC] release chip

Parameters

structnand_chip*chip

NAND chip object

Description

Release chip lock and wake up anyone waiting on the device.

intnand_bbm_get_next_page(structnand_chip * chip, int page)¶

Get the next page for bad block markers

Parameters

structnand_chip*chip

NAND chip object

intpage

First page to start checking for bad block marker usage

Description

Returns an integer that corresponds to the page offset within a block, fora page that is used to store bad block markers. If no more pages areavailable, -EINVAL is returned.

intnand_block_bad(structnand_chip * chip, loff_t ofs)¶

[DEFAULT] Read bad block marker from the chip

Parameters

structnand_chip*chip

NAND chip object

loff_tofs

offset from device start

Description

Check, if the block is bad.

intnand_get_device(structnand_chip * chip)¶

[GENERIC] Get chip for selected access

Parameters

structnand_chip*chip

NAND chip structure

Description

Lock the device and its controller for exclusive access

Return

-EBUSY if the chip has been suspended, 0 otherwise

intnand_check_wp(structnand_chip * chip)¶

[GENERIC] check if the chip is write protected

Parameters

structnand_chip*chip

NAND chip object

Description

Check, if the device is write protected. The function expects, that thedevice is already selected.

uint8_t *nand_fill_oob(structnand_chip * chip, uint8_t * oob, size_t len, struct mtd_oob_ops * ops)¶

[INTERN] Transfer client buffer to oob

Parameters

structnand_chip*chip

NAND chip object

uint8_t*oob

oob data buffer

size_tlen

oob data write length

structmtd_oob_ops*ops

oob ops structure

intnand_do_write_oob(structnand_chip * chip, loff_t to, struct mtd_oob_ops * ops)¶

[MTD Interface] NAND write out-of-band

Parameters

structnand_chip*chip

NAND chip object

loff_tto

offset to write to

structmtd_oob_ops*ops

oob operation description structure

Description

NAND write out-of-band.

intnand_default_block_markbad(structnand_chip * chip, loff_t ofs)¶

[DEFAULT] mark a block bad via bad block marker

Parameters

structnand_chip*chip

NAND chip object

loff_tofs

offset from device start

Description

This is the default implementation, which can be overridden by a hardwarespecific driver. It provides the details for writing a bad block marker to ablock.

intnand_markbad_bbm(structnand_chip * chip, loff_t ofs)¶

mark a block by updating the BBM

Parameters

structnand_chip*chip

NAND chip object

loff_tofs

offset of the block to mark bad

intnand_block_markbad_lowlevel(structnand_chip * chip, loff_t ofs)¶

mark a block bad

Parameters

structnand_chip*chip

NAND chip object

loff_tofs

offset from device start

Description

This function performs the generic NAND bad block marking steps (i.e., badblock table(s) and/or marker(s)). We only allow the hardware driver tospecify how to write bad block markers to OOB (chip->legacy.block_markbad).

We try operations in the following order:

1. erase the affected block, to allow OOB marker to be written cleanly
2. write bad block marker to OOB area of affected block (unless flagNAND_BBT_NO_OOB_BBM is present)
3. update the BBT

Note that we retain the first error encountered in (2) or (3), finish theprocedures, and dump the error in the end.

intnand_block_isreserved(struct mtd_info * mtd, loff_t ofs)¶

[GENERIC] Check if a block is marked reserved.

Parameters

structmtd_info*mtd

MTD device structure

loff_tofs

offset from device start

Description

Check if the block is marked as reserved.

intnand_block_checkbad(structnand_chip * chip, loff_t ofs, int allowbbt)¶

[GENERIC] Check if a block is marked bad

Parameters

structnand_chip*chip

NAND chip object

loff_tofs

offset from device start

intallowbbt

1, if its allowed to access the bbt area

Description

Check, if the block is bad. Either by reading the bad block table orcalling of the scan function.

voidpanic_nand_wait(structnand_chip * chip, unsigned long timeo)¶

[GENERIC] wait until the command is done

Parameters

structnand_chip*chip

NAND chip structure

unsignedlongtimeo

timeout

Description

Wait for command done. This is a helper function for nand_wait used whenwe are in interrupt context. May happen when in panic and trying to writean oops through mtdoops.

intnand_reset_data_interface(structnand_chip * chip, int chipnr)¶

Reset data interface and timings

Parameters

structnand_chip*chip

The NAND chip

intchipnr

Internal die id

Description

Reset the Data interface and timings to ONFI mode 0.

Returns 0 for success or negative error code otherwise.

intnand_setup_data_interface(structnand_chip * chip, int chipnr)¶

Setup the best data interface and timings

Parameters

structnand_chip*chip

The NAND chip

intchipnr

Internal die id

Description

Find and configure the best data interface and NAND timings supported bythe chip and the driver.First tries to retrieve supported timing modes from ONFI information,and if the NAND chip does not support ONFI, relies on the->onfi_timing_mode_default specified in the nand_ids table.

Returns 0 for success or negative error code otherwise.

intnand_init_data_interface(structnand_chip * chip)¶

find the best data interface and timings

Parameters

structnand_chip*chip

The NAND chip

Description

Find the best data interface and NAND timings supported by the chipand the driver.First tries to retrieve supported timing modes from ONFI information,and if the NAND chip does not support ONFI, relies on the->onfi_timing_mode_default specified in the nand_ids table. After thisfunction nand_chip->data_interface is initialized with the best timing modeavailable.

Returns 0 for success or negative error code otherwise.

intnand_fill_column_cycles(structnand_chip * chip, u8 * addrs, unsigned int offset_in_page)¶

fill the column cycles of an address

Parameters

structnand_chip*chip

The NAND chip

u8*addrs

Array of address cycles to fill

unsignedintoffset_in_page

The offset in the page

Description

Fills the first or the first two bytes of theaddrs field dependingon the NAND bus width and the page size.

Returns the number of cycles needed to encode the column, or a negativeerror code in case one of the arguments is invalid.

intnand_read_param_page_op(structnand_chip * chip, u8 page, void * buf, unsigned int len)¶

Do a READ PARAMETER PAGE operation

Parameters

structnand_chip*chip

The NAND chip

u8page

parameter page to read

void*buf

buffer used to store the data

unsignedintlen

length of the buffer

Description

This function issues a READ PARAMETER PAGE operation.This function does not select/unselect the CS line.

Returns 0 on success, a negative error code otherwise.

intnand_exit_status_op(structnand_chip * chip)¶

Exit a STATUS operation

Parameters

structnand_chip*chip

The NAND chip

Description

This function sends a READ0 command to cancel the effect of the STATUScommand to avoid reading only the status until a new read command is sent.

This function does not select/unselect the CS line.

Returns 0 on success, a negative error code otherwise.

intnand_set_features_op(structnand_chip * chip, u8 feature, const void * data)¶

Do a SET FEATURES operation

Parameters

structnand_chip*chip

The NAND chip

u8feature

feature id

constvoid*data

4 bytes of data

Description

This function sends a SET FEATURES command and waits for the NAND to beready before returning.This function does not select/unselect the CS line.

Returns 0 on success, a negative error code otherwise.

intnand_get_features_op(structnand_chip * chip, u8 feature, void * data)¶

Do a GET FEATURES operation

Parameters

structnand_chip*chip

The NAND chip

u8feature

feature id

void*data

4 bytes of data

Description

This function sends a GET FEATURES command and waits for the NAND to beready before returning.This function does not select/unselect the CS line.

Returns 0 on success, a negative error code otherwise.

structnand_op_parser_ctx¶

Context used by the parser

Definition

struct nand_op_parser_ctx {  const struct nand_op_instr *instrs;  unsigned int ninstrs;  struct nand_subop subop;};

Members

instrs

array of all the instructions that must be addressed

ninstrs

length of theinstrs array

subop

Sub-operation to be passed to the NAND controller

Description

This structure is used by the core to split NAND operations intosub-operations that can be handled by the NAND controller.

boolnand_op_parser_must_split_instr(const structnand_op_parser_pattern_elem * pat, const structnand_op_instr * instr, unsigned int * start_offset)¶

Checks if an instruction must be split

Parameters

conststructnand_op_parser_pattern_elem*pat

the parser pattern element that matchesinstr

conststructnand_op_instr*instr

pointer to the instruction to check

unsignedint*start_offset

this is an in/out parameter. Ifinstr has already beensplit, thenstart_offset is the offset from which to start(either an address cycle or an offset in the data buffer).Conversely, if the function returns true (ie. instr must besplit), this parameter is updated to point to the firstdata/address cycle that has not been taken care of.

Description

Some NAND controllers are limited and cannot send X address cycles with aunique operation, or cannot read/write more than Y bytes at the same time.In this case, split the instruction that does not fit in a singlecontroller-operation into two or more chunks.

Returns true if the instruction must be split, false otherwise.Thestart_offset parameter is also updated to the offset at which the nextbundle of instruction must start (if an address or a data instruction).

boolnand_op_parser_match_pat(const structnand_op_parser_pattern * pat, structnand_op_parser_ctx * ctx)¶

Checks if a pattern matches the instructions remaining in the parser context

Parameters

conststructnand_op_parser_pattern*pat

the pattern to test

structnand_op_parser_ctx*ctx

the parser context structure to match with the patternpat

Description

Check ifpat matches the set or a sub-set of instructions remaining inctx.Returns true if this is the case, false ortherwise. When true is returned,ctx->subop is updated with the set of instructions to be passed to thecontroller driver.

intnand_get_features(structnand_chip * chip, int addr, u8 * subfeature_param)¶

wrapper to perform a GET_FEATURE

Parameters

structnand_chip*chip

NAND chip info structure

intaddr

feature address

u8*subfeature_param

the subfeature parameters, a four bytes array

Description

Returns 0 for success, a negative error otherwise. Returns -ENOTSUPP if theoperation cannot be handled.

intnand_set_features(structnand_chip * chip, int addr, u8 * subfeature_param)¶

wrapper to perform a SET_FEATURE

Parameters

structnand_chip*chip

NAND chip info structure

intaddr

feature address

u8*subfeature_param

the subfeature parameters, a four bytes array

Description

Returns 0 for success, a negative error otherwise. Returns -ENOTSUPP if theoperation cannot be handled.

intnand_check_erased_buf(void * buf, int len, int bitflips_threshold)¶

check if a buffer contains (almost) only 0xff data

Parameters

void*buf

buffer to test

intlen

buffer length

intbitflips_threshold

maximum number of bitflips

Description

Check if a buffer contains only 0xff, which means the underlying regionhas been erased and is ready to be programmed.The bitflips_threshold specify the maximum number of bitflips beforeconsidering the region is not erased.Returns a positive number of bitflips less than or equal tobitflips_threshold, or -ERROR_CODE for bitflips in excess of thethreshold.

Note

The logic of this function has been extracted from the memweightimplementation, except that nand_check_erased_buf function exit beforetesting the whole buffer if the number of bitflips exceed thebitflips_threshold value.

intnand_read_page_raw_notsupp(structnand_chip * chip, u8 * buf, int oob_required, int page)¶

dummy read raw page function

Parameters

structnand_chip*chip

nand chip info structure

u8*buf

buffer to store read data

intoob_required

caller requires OOB data read to chip->oob_poi

intpage

page number to read

Description

Returns -ENOTSUPP unconditionally.

intnand_read_page_raw_syndrome(structnand_chip * chip, uint8_t * buf, int oob_required, int page)¶

[INTERN] read raw page data without ecc

Parameters

structnand_chip*chip

nand chip info structure

uint8_t*buf

buffer to store read data

intoob_required

caller requires OOB data read to chip->oob_poi

intpage

page number to read

Description

We need a special oob layout and handling even when OOB isn’t used.

intnand_read_page_swecc(structnand_chip * chip, uint8_t * buf, int oob_required, int page)¶

[REPLACEABLE] software ECC based page read function

Parameters

structnand_chip*chip

nand chip info structure

uint8_t*buf

buffer to store read data

intoob_required

caller requires OOB data read to chip->oob_poi

intpage

page number to read

intnand_read_subpage(structnand_chip * chip, uint32_t data_offs, uint32_t readlen, uint8_t * bufpoi, int page)¶

[REPLACEABLE] ECC based sub-page read function

Parameters

structnand_chip*chip

nand chip info structure

uint32_tdata_offs

offset of requested data within the page

uint32_treadlen

data length

uint8_t*bufpoi

buffer to store read data

intpage

page number to read

intnand_read_page_hwecc(structnand_chip * chip, uint8_t * buf, int oob_required, int page)¶

[REPLACEABLE] hardware ECC based page read function

Parameters

structnand_chip*chip

nand chip info structure

uint8_t*buf

buffer to store read data

intoob_required

caller requires OOB data read to chip->oob_poi

intpage

page number to read

Description

Not for syndrome calculating ECC controllers which need a special oob layout.

intnand_read_page_syndrome(structnand_chip * chip, uint8_t * buf, int oob_required, int page)¶

[REPLACEABLE] hardware ECC syndrome based page read

Parameters

structnand_chip*chip

nand chip info structure

uint8_t*buf

buffer to store read data

intoob_required

caller requires OOB data read to chip->oob_poi

intpage

page number to read

Description

The hw generator calculates the error syndrome automatically. Therefore weneed a special oob layout and handling.

uint8_t *nand_transfer_oob(structnand_chip * chip, uint8_t * oob, struct mtd_oob_ops * ops, size_t len)¶

[INTERN] Transfer oob to client buffer

Parameters

structnand_chip*chip

NAND chip object

uint8_t*oob

oob destination address

structmtd_oob_ops*ops

oob ops structure

size_tlen

size of oob to transfer

intnand_setup_read_retry(structnand_chip * chip, int retry_mode)¶

[INTERN] Set the READ RETRY mode

Parameters

structnand_chip*chip

NAND chip object

intretry_mode

the retry mode to use

Description

Some vendors supply a special command to shift the Vt threshold, to be usedwhen there are too many bitflips in a page (i.e., ECC error). After settinga new threshold, the host should retry reading the page.

intnand_do_read_ops(structnand_chip * chip, loff_t from, struct mtd_oob_ops * ops)¶

[INTERN] Read data with ECC

Parameters

structnand_chip*chip

NAND chip object

loff_tfrom

offset to read from

structmtd_oob_ops*ops

oob ops structure

Description

Internal function. Called with chip held.

intnand_read_oob_syndrome(structnand_chip * chip, int page)¶

[REPLACEABLE] OOB data read function for HW ECC with syndromes

Parameters

structnand_chip*chip

nand chip info structure

intpage

page number to read

intnand_write_oob_syndrome(structnand_chip * chip, int page)¶

[REPLACEABLE] OOB data write function for HW ECC with syndrome - only for large page flash

Parameters

structnand_chip*chip

nand chip info structure

intpage

page number to write

intnand_do_read_oob(structnand_chip * chip, loff_t from, struct mtd_oob_ops * ops)¶

[INTERN] NAND read out-of-band

Parameters

structnand_chip*chip

NAND chip object

loff_tfrom

offset to read from

structmtd_oob_ops*ops

oob operations description structure

Description

NAND read out-of-band data from the spare area.

intnand_read_oob(struct mtd_info * mtd, loff_t from, struct mtd_oob_ops * ops)¶

[MTD Interface] NAND read data and/or out-of-band

Parameters

structmtd_info*mtd

MTD device structure

loff_tfrom

offset to read from

structmtd_oob_ops*ops

oob operation description structure

Description

NAND read data and/or out-of-band data.

intnand_write_page_raw_notsupp(structnand_chip * chip, const u8 * buf, int oob_required, int page)¶

dummy raw page write function

Parameters

structnand_chip*chip

nand chip info structure

constu8*buf

data buffer

intoob_required

must write chip->oob_poi to OOB

intpage

page number to write

Description

Returns -ENOTSUPP unconditionally.

intnand_write_page_raw_syndrome(structnand_chip * chip, const uint8_t * buf, int oob_required, int page)¶

[INTERN] raw page write function

Parameters

structnand_chip*chip

nand chip info structure

constuint8_t*buf

data buffer

intoob_required

must write chip->oob_poi to OOB

intpage

page number to write

Description

We need a special oob layout and handling even when ECC isn’t checked.

intnand_write_page_swecc(structnand_chip * chip, const uint8_t * buf, int oob_required, int page)¶

[REPLACEABLE] software ECC based page write function

Parameters

structnand_chip*chip

nand chip info structure

constuint8_t*buf

data buffer

intoob_required

must write chip->oob_poi to OOB

intpage

page number to write

intnand_write_page_hwecc(structnand_chip * chip, const uint8_t * buf, int oob_required, int page)¶

[REPLACEABLE] hardware ECC based page write function

Parameters

structnand_chip*chip

nand chip info structure

constuint8_t*buf

data buffer

intoob_required

must write chip->oob_poi to OOB

intpage

page number to write

intnand_write_subpage_hwecc(structnand_chip * chip, uint32_t offset, uint32_t data_len, const uint8_t * buf, int oob_required, int page)¶

[REPLACEABLE] hardware ECC based subpage write

Parameters

structnand_chip*chip

nand chip info structure

uint32_toffset

column address of subpage within the page

uint32_tdata_len

data length

constuint8_t*buf

data buffer

intoob_required

must write chip->oob_poi to OOB

intpage

page number to write

intnand_write_page_syndrome(structnand_chip * chip, const uint8_t * buf, int oob_required, int page)¶

[REPLACEABLE] hardware ECC syndrome based page write

Parameters

structnand_chip*chip

nand chip info structure

constuint8_t*buf

data buffer

intoob_required

must write chip->oob_poi to OOB

intpage

page number to write

Description

The hw generator calculates the error syndrome automatically. Therefore weneed a special oob layout and handling.

intnand_write_page(structnand_chip * chip, uint32_t offset, int data_len, const uint8_t * buf, int oob_required, int page, int raw)¶

write one page

Parameters

structnand_chip*chip

NAND chip descriptor

uint32_toffset

address offset within the page

intdata_len

length of actual data to be written

constuint8_t*buf

the data to write

intoob_required

must write chip->oob_poi to OOB

intpage

page number to write

intraw

use _raw version of write_page

intnand_do_write_ops(structnand_chip * chip, loff_t to, struct mtd_oob_ops * ops)¶

[INTERN] NAND write with ECC

Parameters

structnand_chip*chip

NAND chip object

loff_tto

offset to write to

structmtd_oob_ops*ops

oob operations description structure

Description

NAND write with ECC.

intpanic_nand_write(struct mtd_info * mtd, loff_t to, size_t len, size_t * retlen, const uint8_t * buf)¶

[MTD Interface] NAND write with ECC

Parameters

structmtd_info*mtd

MTD device structure

loff_tto

offset to write to

size_tlen

number of bytes to write

size_t*retlen

pointer to variable to store the number of written bytes

constuint8_t*buf

the data to write

Description

NAND write with ECC. Used when performing writes in interrupt context, thismay for example be called by mtdoops when writing an oops while in panic.

intnand_write_oob(struct mtd_info * mtd, loff_t to, struct mtd_oob_ops * ops)¶

[MTD Interface] NAND write data and/or out-of-band

Parameters

structmtd_info*mtd

MTD device structure

loff_tto

offset to write to

structmtd_oob_ops*ops

oob operation description structure

intnand_erase(struct mtd_info * mtd, struct erase_info * instr)¶

[MTD Interface] erase block(s)

Parameters

structmtd_info*mtd

MTD device structure

structerase_info*instr

erase instruction

Description

Erase one ore more blocks.

intnand_erase_nand(structnand_chip * chip, struct erase_info * instr, int allowbbt)¶

[INTERN] erase block(s)

Parameters

structnand_chip*chip

NAND chip object

structerase_info*instr

erase instruction

intallowbbt

allow erasing the bbt area

Description

Erase one ore more blocks.

voidnand_sync(struct mtd_info * mtd)¶

[MTD Interface] sync

Parameters

structmtd_info*mtd

MTD device structure

Description

Sync is actually a wait for chip ready function.

intnand_block_isbad(struct mtd_info * mtd, loff_t offs)¶

[MTD Interface] Check if block at offset is bad

Parameters

structmtd_info*mtd

MTD device structure

loff_toffs

offset relative to mtd start

intnand_block_markbad(struct mtd_info * mtd, loff_t ofs)¶

[MTD Interface] Mark block at the given offset as bad

Parameters

structmtd_info*mtd

MTD device structure

loff_tofs

offset relative to mtd start

intnand_suspend(struct mtd_info * mtd)¶

[MTD Interface] Suspend the NAND flash

Parameters

structmtd_info*mtd

MTD device structure

Description

Returns 0 for success or negative error code otherwise.

voidnand_resume(struct mtd_info * mtd)¶

[MTD Interface] Resume the NAND flash

Parameters

structmtd_info*mtd

MTD device structure

voidnand_shutdown(struct mtd_info * mtd)¶

[MTD Interface] Finish the current NAND operation and prevent further operations

Parameters

structmtd_info*mtd

MTD device structure

intnand_lock(struct mtd_info * mtd, loff_t ofs, uint64_t len)¶

[MTD Interface] Lock the NAND flash

Parameters

structmtd_info*mtd

MTD device structure

loff_tofs

offset byte address

uint64_tlen

number of bytes to lock (must be a multiple of block/page size)

intnand_unlock(struct mtd_info * mtd, loff_t ofs, uint64_t len)¶

[MTD Interface] Unlock the NAND flash

Parameters

structmtd_info*mtd

MTD device structure

loff_tofs

offset byte address

uint64_tlen

number of bytes to unlock (must be a multiple of block/page size)

intnand_scan_ident(structnand_chip * chip, unsigned int maxchips, structnand_flash_dev * table)¶

Scan for the NAND device

Parameters

structnand_chip*chip

NAND chip object

unsignedintmaxchips

number of chips to scan for

structnand_flash_dev*table

alternative NAND ID table

Description

This is the first phase of the normal nand_scan() function. It reads theflash ID and sets up MTD fields accordingly.

This helper used to be called directly from controller drivers that neededto tweak some ECC-related parameters beforenand_scan_tail(). This separationprevented dynamic allocations during this phase which was unconvenient andas been banned for the benefit of the ->init_ecc()/cleanup_ecc() hooks.

intnand_check_ecc_caps(structnand_chip * chip, const structnand_ecc_caps * caps, int oobavail)¶

check the sanity of preset ECC settings

Parameters

structnand_chip*chip

nand chip info structure

conststructnand_ecc_caps*caps

ECC caps info structure

intoobavail

OOB size that the ECC engine can use

Description

When ECC step size and strength are already set, check if they are supportedby the controller and the calculated ECC bytes fit within the chip’s OOB.On success, the calculated ECC bytes is set.

intnand_match_ecc_req(structnand_chip * chip, const structnand_ecc_caps * caps, int oobavail)¶

meet the chip’s requirement with least ECC bytes

Parameters

structnand_chip*chip

nand chip info structure

conststructnand_ecc_caps*caps

ECC engine caps info structure

intoobavail

OOB size that the ECC engine can use

Description

If a chip’s ECC requirement is provided, try to meet it with the leastnumber of ECC bytes (i.e. with the largest number of OOB-free bytes).On success, the chosen ECC settings are set.

intnand_maximize_ecc(structnand_chip * chip, const structnand_ecc_caps * caps, int oobavail)¶

choose the max ECC strength available

Parameters

structnand_chip*chip

nand chip info structure

conststructnand_ecc_caps*caps

ECC engine caps info structure

intoobavail

OOB size that the ECC engine can use

Description

Choose the max ECC strength that is supported on the controller, and can fitwithin the chip’s OOB. On success, the chosen ECC settings are set.

intnand_scan_tail(structnand_chip * chip)¶

Scan for the NAND device

Parameters

structnand_chip*chip

NAND chip object

Description

This is the second phase of the normal nand_scan() function. It fills outall the uninitialized function pointers with the defaults and scans for abad block table if appropriate.

intcheck_pattern(uint8_t * buf, int len, int paglen, struct nand_bbt_descr * td)¶

[GENERIC] check if a pattern is in the buffer

Parameters

uint8_t*buf

the buffer to search

intlen

the length of buffer to search

intpaglen

the pagelength

structnand_bbt_descr*td

search pattern descriptor

Description

Check for a pattern at the given place. Used to search bad block tables andgood / bad block identifiers.

intcheck_short_pattern(uint8_t * buf, struct nand_bbt_descr * td)¶

[GENERIC] check if a pattern is in the buffer

Parameters

uint8_t*buf

the buffer to search

structnand_bbt_descr*td

search pattern descriptor

Description

Check for a pattern at the given place. Used to search bad block tables andgood / bad block identifiers. Same as check_pattern, but no optional emptycheck.

u32add_marker_len(struct nand_bbt_descr * td)¶

compute the length of the marker in data area

Parameters

structnand_bbt_descr*td

BBT descriptor used for computation

Description

The length will be 0 if the marker is located in OOB area.

intread_bbt(structnand_chip * this, uint8_t * buf, int page, int num, struct nand_bbt_descr * td, int offs)¶

[GENERIC] Read the bad block table starting from page

Parameters

structnand_chip*this

NAND chip object

uint8_t*buf

temporary buffer

intpage

the starting page

intnum

the number of bbt descriptors to read

structnand_bbt_descr*td

the bbt describtion table

intoffs

block number offset in the table

Description

Read the bad block table starting from page.

intread_abs_bbt(structnand_chip * this, uint8_t * buf, struct nand_bbt_descr * td, int chip)¶

[GENERIC] Read the bad block table starting at a given page

Parameters

structnand_chip*this

NAND chip object

uint8_t*buf

temporary buffer

structnand_bbt_descr*td

descriptor for the bad block table

intchip

read the table for a specific chip, -1 read all chips; applies only ifNAND_BBT_PERCHIP option is set

Description

Read the bad block table for all chips starting at a given page. We assumethat the bbt bits are in consecutive order.

intscan_read_oob(structnand_chip * this, uint8_t * buf, loff_t offs, size_t len)¶

[GENERIC] Scan data+OOB region to buffer

Parameters

structnand_chip*this

NAND chip object

uint8_t*buf

temporary buffer

loff_toffs

offset at which to scan

size_tlen

length of data region to read

Description

Scan read data from data+OOB. May traverse multiple pages, interleavingpage,OOB,page,OOB,… in buf. Completes transfer and returns the “strongest”ECC condition (error or bitflip). May quit on the first (non-ECC) error.

voidread_abs_bbts(structnand_chip * this, uint8_t * buf, struct nand_bbt_descr * td, struct nand_bbt_descr * md)¶

[GENERIC] Read the bad block table(s) for all chips starting at a given page

Parameters

structnand_chip*this

NAND chip object

uint8_t*buf

temporary buffer

structnand_bbt_descr*td

descriptor for the bad block table

structnand_bbt_descr*md

descriptor for the bad block table mirror

Description

Read the bad block table(s) for all chips starting at a given page. Weassume that the bbt bits are in consecutive order.

intcreate_bbt(structnand_chip * this, uint8_t * buf, struct nand_bbt_descr * bd, int chip)¶

[GENERIC] Create a bad block table by scanning the device

Parameters

structnand_chip*this

NAND chip object

uint8_t*buf

temporary buffer

structnand_bbt_descr*bd

descriptor for the good/bad block search pattern

intchip

create the table for a specific chip, -1 read all chips; applies onlyif NAND_BBT_PERCHIP option is set

Description

Create a bad block table by scanning the device for the given good/bad blockidentify pattern.

intsearch_bbt(structnand_chip * this, uint8_t * buf, struct nand_bbt_descr * td)¶

[GENERIC] scan the device for a specific bad block table

Parameters

structnand_chip*this

NAND chip object

uint8_t*buf

temporary buffer

structnand_bbt_descr*td

descriptor for the bad block table

Description

Read the bad block table by searching for a given ident pattern. Search ispreformed either from the beginning up or from the end of the devicedownwards. The search starts always at the start of a block. If the optionNAND_BBT_PERCHIP is given, each chip is searched for a bbt, which containsthe bad block information of this chip. This is necessary to provide supportfor certain DOC devices.

The bbt ident pattern resides in the oob area of the first page in a block.

voidsearch_read_bbts(structnand_chip * this, uint8_t * buf, struct nand_bbt_descr * td, struct nand_bbt_descr * md)¶

[GENERIC] scan the device for bad block table(s)

Parameters

structnand_chip*this

NAND chip object

uint8_t*buf

temporary buffer

structnand_bbt_descr*td

descriptor for the bad block table

structnand_bbt_descr*md

descriptor for the bad block table mirror

Description

Search and read the bad block table(s).

intget_bbt_block(structnand_chip * this, struct nand_bbt_descr * td, struct nand_bbt_descr * md, int chip)¶

Get the first valid eraseblock suitable to store a BBT

Parameters

structnand_chip*this

the NAND device

structnand_bbt_descr*td

the BBT description

structnand_bbt_descr*md

the mirror BBT descriptor

intchip

the CHIP selector

Description

This functions returns a positive block number pointing a valid eraseblocksuitable to store a BBT (i.e. in the range reserved for BBT), or -ENOSPC ifall blocks are already used of marked bad. If td->pages[chip] was alreadypointing to a valid block we re-use it, otherwise we search for the nextvalid one.

voidmark_bbt_block_bad(structnand_chip * this, struct nand_bbt_descr * td, int chip, int block)¶

Mark one of the block reserved for BBT bad

Parameters

structnand_chip*this

the NAND device

structnand_bbt_descr*td

the BBT description

intchip

the CHIP selector

intblock

the BBT block to mark

Description

Blocks reserved for BBT can become bad. This functions is an helper to marksuch blocks as bad. It takes care of updating the in-memory BBT, marking theblock as bad using a bad block marker and invalidating the associatedtd->pages[] entry.

intwrite_bbt(structnand_chip * this, uint8_t * buf, struct nand_bbt_descr * td, struct nand_bbt_descr * md, int chipsel)¶

[GENERIC] (Re)write the bad block table

Parameters

structnand_chip*this

NAND chip object

uint8_t*buf

temporary buffer

structnand_bbt_descr*td

descriptor for the bad block table

structnand_bbt_descr*md

descriptor for the bad block table mirror

intchipsel

selector for a specific chip, -1 for all

Description

(Re)write the bad block table.

intnand_memory_bbt(structnand_chip * this, struct nand_bbt_descr * bd)¶

[GENERIC] create a memory based bad block table

Parameters

structnand_chip*this

NAND chip object

structnand_bbt_descr*bd

descriptor for the good/bad block search pattern

Description

The function creates a memory based bbt by scanning the device formanufacturer / software marked good / bad blocks.

intcheck_create(structnand_chip * this, uint8_t * buf, struct nand_bbt_descr * bd)¶

[GENERIC] create and write bbt(s) if necessary

Parameters

structnand_chip*this

the NAND device

uint8_t*buf

temporary buffer

structnand_bbt_descr*bd

descriptor for the good/bad block search pattern

Description

The function checks the results of the previous call to read_bbt and creates/ updates the bbt(s) if necessary. Creation is necessary if no bbt was foundfor the chip/device. Update is necessary if one of the tables is missing orthe version nr. of one table is less than the other.

intnand_update_bbt(structnand_chip * this, loff_t offs)¶

update bad block table(s)

Parameters

structnand_chip*this

the NAND device

loff_toffs

the offset of the newly marked block

Description

The function updates the bad block table(s).

voidmark_bbt_region(structnand_chip * this, struct nand_bbt_descr * td)¶

[GENERIC] mark the bad block table regions

Parameters

structnand_chip*this

the NAND device

structnand_bbt_descr*td

bad block table descriptor

Description

The bad block table regions are marked as “bad” to prevent accidentalerasures / writes. The regions are identified by the mark 0x02.

voidverify_bbt_descr(structnand_chip * this, struct nand_bbt_descr * bd)¶

verify the bad block description

Parameters

structnand_chip*this

the NAND device

structnand_bbt_descr*bd

the table to verify

Description

This functions performs a few sanity checks on the bad block descriptiontable.

intnand_scan_bbt(structnand_chip * this, struct nand_bbt_descr * bd)¶

[NAND Interface] scan, find, read and maybe create bad block table(s)

Parameters

structnand_chip*this

the NAND device

structnand_bbt_descr*bd

descriptor for the good/bad block search pattern

Description

The function checks, if a bad block table(s) is/are already available. Ifnot it scans the device for manufacturer marked good / bad blocks and writesthe bad block table(s) to the selected place.

The bad block table memory is allocated here. It must be freed by callingthe nand_free_bbt function.

intnand_create_badblock_pattern(structnand_chip * this)¶

[INTERN] Creates a BBT descriptor structure

Parameters

structnand_chip*this

NAND chip to create descriptor for

Description

This function allocates and initializes a nand_bbt_descr for BBM detectionbased on the properties ofthis. The new descriptor is stored inthis->badblock_pattern. Thus, this->badblock_pattern should be NULL whenpassed to this function.

intnand_isreserved_bbt(structnand_chip * this, loff_t offs)¶

[NAND Interface] Check if a block is reserved

Parameters

structnand_chip*this

NAND chip object

loff_toffs

offset in the device

intnand_isbad_bbt(structnand_chip * this, loff_t offs, int allowbbt)¶

[NAND Interface] Check if a block is bad

Parameters

structnand_chip*this

NAND chip object

loff_toffs

offset in the device

intallowbbt

allow access to bad block table region

intnand_markbad_bbt(structnand_chip * this, loff_t offs)¶

[NAND Interface] Mark a block bad in the BBT

Parameters

structnand_chip*this

NAND chip object

loff_toffs

offset of the bad block

Credits¶

The following people have contributed to the NAND driver:

1. Steven J. Hillsjhill@realitydiluted.com
2. David Woodhousedwmw2@infradead.org
3. Thomas Gleixnertglx@linutronix.de

A lot of users have provided bugfixes, improvements and helping handsfor testing. Thanks a lot.

The following people have contributed to this document:

1. Thomas Gleixnertglx@linutronix.de