/dev 폴더에 있는 node파일 중에서 어떤 것을 open해야 nand 플래쉬를 사용할 수 있을까요?

아래 그림은 제 임베디드 리눅스의 /dev 폴더를 캡쳐한 것입니다.

제 리눅스를 만들 때 Flash Driver를 추가되었다는 것을 Kconfig와 menuconfig로 확인했습니다. (디폴트 셋팅으로 되어있음)

그런데 ... 이 드라이버가 /dev 폴더 밑에 어딘가에 있지 않을까? 생각했는데 /dev 폴더 밑을 보니 Flash관련 된 이름이 없는거

같더라구요..

그래서 제가 nand flash 과련 드라이버를 확인해서 주 번호를 확인 하려고 하니 이 드라이버는 주 번호를 어디서 봐야 할지 ㅠㅠ

도저히 모르는 코드더군요... 아래 코드는 제 리눅스에 포팅된 nand flash 드라이버 코드입니다.

어디서 이 nand flash driver의 주 번호를 확인 할 수 있을까요? 또한, 이 드라이버를 Application에서 사용하려면 어떤 절차가 있어야 하나요 ㅠㅠ; 고수님들의 조언 부탁드립니다.

======================== nand flash driver =====================================

/*
* Copyright (C) 2003 Rick Bronson
*
* Derived from drivers/mtd/nand/autcpu12.c
* Copyright (c) 2001 Thomas Gleixner (gleixner@autronix.de)
*
* Derived from drivers/mtd/spia.c
* Copyright (C) 2000 Steven J. Hill (sjhill@cotw.com)
*
*
* Add Hardware ECC support for AT91SAM9260 / AT91SAM9263
* Richard Genoud (richard.genoud@gmail.com), Adeneo Copyright (C) 2007
*
* Derived from Das U-Boot source code
* (u-boot-1.1.5/board/atmel/at91sam9263ek/nand.c)
* (C) Copyright 2006 ATMEL Rousset, Lacressonniere Nicolas
*
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/

#include
#include
#include
#include
#include
#include

#include
#include

#include
#include

#ifdef CONFIG_MTD_NAND_ATMEL_ECC_HW
#define hard_ecc 1
#else
#define hard_ecc 0
#endif

#ifdef CONFIG_MTD_NAND_ATMEL_ECC_NONE
#define no_ecc 1
#else
#define no_ecc 0
#endif

/* Register access macros */
#define ecc_readl(add, reg) \
__raw_readl(add + ATMEL_ECC_##reg)
#define ecc_writel(add, reg, value) \
__raw_writel((value), add + ATMEL_ECC_##reg)

#include "atmel_nand_ecc.h" /* Hardware ECC registers */

/* oob layout for large page size
* bad block info is on bytes 0 and 1
* the bytes have to be consecutives to avoid
* several NAND_CMD_RNDOUT during read
*/
static struct nand_ecclayout atmel_oobinfo_large = {
.eccbytes = 4,
.eccpos = {60, 61, 62, 63},
.oobfree = {
{2, 58}
},
};

/* oob layout for small page size
* bad block info is on bytes 4 and 5
* the bytes have to be consecutives to avoid
* several NAND_CMD_RNDOUT during read
*/
static struct nand_ecclayout atmel_oobinfo_small = {
.eccbytes = 4,
.eccpos = {0, 1, 2, 3},
.oobfree = {
{6, 10}
},
};

struct atmel_nand_host {
struct nand_chip nand_chip;
struct mtd_info mtd;
void __iomem *io_base;
struct atmel_nand_data *board;
struct device *dev;
void __iomem *ecc;
};

/*
* Enable NAND.
*/
static void atmel_nand_enable(struct atmel_nand_host *host)
{
if (host->board->enable_pin)
gpio_set_value(host->board->enable_pin, 0);
}

/*
* Disable NAND.
*/
static void atmel_nand_disable(struct atmel_nand_host *host)
{
if (host->board->enable_pin)
gpio_set_value(host->board->enable_pin, 1);
}

/*
* Hardware specific access to control-lines
*/
static void atmel_nand_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
{
struct nand_chip *nand_chip = mtd->priv;
struct atmel_nand_host *host = nand_chip->priv;

if (ctrl & NAND_CTRL_CHANGE) {
if (ctrl & NAND_NCE)
atmel_nand_enable(host);
else
atmel_nand_disable(host);
}
if (cmd == NAND_CMD_NONE)
return;

if (ctrl & NAND_CLE)
writeb(cmd, host->io_base + (1 << host->board->cle));
else
writeb(cmd, host->io_base + (1 << host->board->ale));
}

/*
* Read the Device Ready pin.
*/
static int atmel_nand_device_ready(struct mtd_info *mtd)
{
struct nand_chip *nand_chip = mtd->priv;
struct atmel_nand_host *host = nand_chip->priv;

return gpio_get_value(host->board->rdy_pin) ^
!!host->board->rdy_pin_active_low;
}

/*
* Minimal-overhead PIO for data access.
*/
static void atmel_read_buf(struct mtd_info *mtd, u8 *buf, int len)
{
struct nand_chip *nand_chip = mtd->priv;

__raw_readsb(nand_chip->IO_ADDR_R, buf, len);
}

static void atmel_read_buf16(struct mtd_info *mtd, u8 *buf, int len)
{
struct nand_chip *nand_chip = mtd->priv;

__raw_readsw(nand_chip->IO_ADDR_R, buf, len / 2);
}

static void atmel_write_buf(struct mtd_info *mtd, const u8 *buf, int len)
{
struct nand_chip *nand_chip = mtd->priv;

__raw_writesb(nand_chip->IO_ADDR_W, buf, len);
}

static void atmel_write_buf16(struct mtd_info *mtd, const u8 *buf, int len)
{
struct nand_chip *nand_chip = mtd->priv;

__raw_writesw(nand_chip->IO_ADDR_W, buf, len / 2);
}

/*
* Calculate HW ECC
*
* function called after a write
*
* mtd: MTD block structure
* dat: raw data (unused)
* ecc_code: buffer for ECC
*/
static int atmel_nand_calculate(struct mtd_info *mtd,
const u_char *dat, unsigned char *ecc_code)
{
struct nand_chip *nand_chip = mtd->priv;
struct atmel_nand_host *host = nand_chip->priv;
uint32_t *eccpos = nand_chip->ecc.layout->eccpos;
unsigned int ecc_value;

/* get the first 2 ECC bytes */
ecc_value = ecc_readl(host->ecc, PR);

ecc_code[0] = ecc_value & 0xFF;
ecc_code[1] = (ecc_value >> 8) & 0xFF;

/* get the last 2 ECC bytes */
ecc_value = ecc_readl(host->ecc, NPR) & ATMEL_ECC_NPARITY;

ecc_code[2] = ecc_value & 0xFF;
ecc_code[3] = (ecc_value >> 8) & 0xFF;

return 0;
}

/*
* HW ECC read page function
*
* mtd: mtd info structure
* chip: nand chip info structure
* buf: buffer to store read data
*/
static int atmel_nand_read_page(struct mtd_info *mtd,
struct nand_chip *chip, uint8_t *buf)
{
int eccsize = chip->ecc.size;
int eccbytes = chip->ecc.bytes;
uint32_t *eccpos = chip->ecc.layout->eccpos;
uint8_t *p = buf;
uint8_t *oob = chip->oob_poi;
uint8_t *ecc_pos;
int stat;

/*
* Errata: ALE is incorrectly wired up to the ECC controller
* on the AP7000, so it will include the address cycles in the
* ECC calculation.
*
* Workaround: Reset the parity registers before reading the
* actual data.
*/
if (cpu_is_at32ap7000()) {
struct atmel_nand_host *host = chip->priv;
ecc_writel(host->ecc, CR, ATMEL_ECC_RST);
}

/* read the page */
chip->read_buf(mtd, p, eccsize);

/* move to ECC position if needed */
if (eccpos[0] != 0) {
/* This only works on large pages
* because the ECC controller waits for
* NAND_CMD_RNDOUTSTART after the
* NAND_CMD_RNDOUT.
* anyway, for small pages, the eccpos[0] == 0
*/
chip->cmdfunc(mtd, NAND_CMD_RNDOUT,
mtd->writesize + eccpos[0], -1);
}

/* the ECC controller needs to read the ECC just after the data */
ecc_pos = oob + eccpos[0];
chip->read_buf(mtd, ecc_pos, eccbytes);

/* check if there's an error */
stat = chip->ecc.correct(mtd, p, oob, NULL);

if (stat < 0)
mtd->ecc_stats.failed++;
else
mtd->ecc_stats.corrected += stat;

/* get back to oob start (end of page) */
chip->cmdfunc(mtd, NAND_CMD_RNDOUT, mtd->writesize, -1);

/* read the oob */
chip->read_buf(mtd, oob, mtd->oobsize);

return 0;
}

/*
* HW ECC Correction
*
* function called after a read
*
* mtd: MTD block structure
* dat: raw data read from the chip
* read_ecc: ECC from the chip (unused)
* isnull: unused
*
* Detect and correct a 1 bit error for a page
*/
static int atmel_nand_correct(struct mtd_info *mtd, u_char *dat,
u_char *read_ecc, u_char *isnull)
{
struct nand_chip *nand_chip = mtd->priv;
struct atmel_nand_host *host = nand_chip->priv;
unsigned int ecc_status;
unsigned int ecc_word, ecc_bit;

/* get the status from the Status Register */
ecc_status = ecc_readl(host->ecc, SR);

/* if there's no error */
if (likely(!(ecc_status & ATMEL_ECC_RECERR)))
return 0;

/* get error bit offset (4 bits) */
ecc_bit = ecc_readl(host->ecc, PR) & ATMEL_ECC_BITADDR;
/* get word address (12 bits) */
ecc_word = ecc_readl(host->ecc, PR) & ATMEL_ECC_WORDADDR;
ecc_word >>= 4;

/* if there are multiple errors */
if (ecc_status & ATMEL_ECC_MULERR) {
/* check if it is a freshly erased block
* (filled with 0xff) */
if ((ecc_bit == ATMEL_ECC_BITADDR)
&& (ecc_word == (ATMEL_ECC_WORDADDR >> 4))) {
/* the block has just been erased, return OK */
return 0;
}
/* it doesn't seems to be a freshly
* erased block.
* We can't correct so many errors */
dev_dbg(host->dev, "atmel_nand : multiple errors detected."
" Unable to correct.\n");
return -EIO;
}

/* if there's a single bit error : we can correct it */
if (ecc_status & ATMEL_ECC_ECCERR) {
/* there's nothing much to do here.
* the bit error is on the ECC itself.
*/
dev_dbg(host->dev, "atmel_nand : one bit error on ECC code."
" Nothing to correct\n");
return 0;
}

dev_dbg(host->dev, "atmel_nand : one bit error on data."
" (word offset in the page :"
" 0x%x bit offset : 0x%x)\n",
ecc_word, ecc_bit);
/* correct the error */
if (nand_chip->options & NAND_BUSWIDTH_16) {
/* 16 bits words */
((unsigned short *) dat)[ecc_word] ^= (1 << ecc_bit);
} else {
/* 8 bits words */
dat[ecc_word] ^= (1 << ecc_bit);
}
dev_dbg(host->dev, "atmel_nand : error corrected\n");
return 1;
}

/*
* Enable HW ECC : unused on most chips
*/
static void atmel_nand_hwctl(struct mtd_info *mtd, int mode)
{
if (cpu_is_at32ap7000()) {
struct nand_chip *nand_chip = mtd->priv;
struct atmel_nand_host *host = nand_chip->priv;
ecc_writel(host->ecc, CR, ATMEL_ECC_RST);
}
}

#ifdef CONFIG_MTD_PARTITIONS
static const char *part_probes[] = { "cmdlinepart", NULL };
#endif

/*
* Probe for the NAND device.
*/
static int __init atmel_nand_probe(struct platform_device *pdev)
{
struct atmel_nand_host *host;
struct mtd_info *mtd;
struct nand_chip *nand_chip;
struct resource *regs;
struct resource *mem;
int res;

#ifdef CONFIG_MTD_PARTITIONS
struct mtd_partition *partitions = NULL;
int num_partitions = 0;
#endif

mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!mem) {
printk(KERN_ERR "atmel_nand: can't get I/O resource mem\n");
return -ENXIO;
}

/* Allocate memory for the device structure (and zero it) */
host = kzalloc(sizeof(struct atmel_nand_host), GFP_KERNEL);
if (!host) {
printk(KERN_ERR "atmel_nand: failed to allocate device structure.\n");
return -ENOMEM;
}

host->io_base = ioremap(mem->start, mem->end - mem->start + 1);
if (host->io_base == NULL) {
printk(KERN_ERR "atmel_nand: ioremap failed\n");
res = -EIO;
goto err_nand_ioremap;
}

mtd = &host->mtd;
nand_chip = &host->nand_chip;
host->board = pdev->dev.platform_data;
host->dev = &pdev->dev;

nand_chip->priv = host; /* link the private data structures */
mtd->priv = nand_chip;
mtd->owner = THIS_MODULE;

/* Set address of NAND IO lines */
nand_chip->IO_ADDR_R = host->io_base;
nand_chip->IO_ADDR_W = host->io_base;
nand_chip->cmd_ctrl = atmel_nand_cmd_ctrl;

if (host->board->rdy_pin)
nand_chip->dev_ready = atmel_nand_device_ready;

regs = platform_get_resource(pdev, IORESOURCE_MEM, 1);
if (!regs && hard_ecc) {
printk(KERN_ERR "atmel_nand: can't get I/O resource "
"regs\nFalling back on software ECC\n");
}

nand_chip->ecc.mode = NAND_ECC_SOFT; /* enable ECC */
if (no_ecc)
nand_chip->ecc.mode = NAND_ECC_NONE;
if (hard_ecc && regs) {
host->ecc = ioremap(regs->start, regs->end - regs->start + 1);
if (host->ecc == NULL) {
printk(KERN_ERR "atmel_nand: ioremap failed\n");
res = -EIO;
goto err_ecc_ioremap;
}
nand_chip->ecc.mode = NAND_ECC_HW;
nand_chip->ecc.calculate = atmel_nand_calculate;
nand_chip->ecc.correct = atmel_nand_correct;
nand_chip->ecc.hwctl = atmel_nand_hwctl;
nand_chip->ecc.read_page = atmel_nand_read_page;
nand_chip->ecc.bytes = 4;
}

nand_chip->chip_delay = 20; /* 20us command delay time */

if (host->board->bus_width_16) { /* 16-bit bus width */
nand_chip->options |= NAND_BUSWIDTH_16;
nand_chip->read_buf = atmel_read_buf16;
nand_chip->write_buf = atmel_write_buf16;
} else {
nand_chip->read_buf = atmel_read_buf;
nand_chip->write_buf = atmel_write_buf;
}

platform_set_drvdata(pdev, host);
atmel_nand_enable(host);

if (host->board->det_pin) {
if (gpio_get_value(host->board->det_pin)) {
printk("No SmartMedia card inserted.\n");
res = ENXIO;
goto err_no_card;
}
}

/* first scan to find the device and get the page size */
if (nand_scan_ident(mtd, 1)) {
res = -ENXIO;
goto err_scan_ident;
}

if (nand_chip->ecc.mode == NAND_ECC_HW) {
/* ECC is calculated for the whole page (1 step) */
nand_chip->ecc.size = mtd->writesize;

/* set ECC page size and oob layout */
switch (mtd->writesize) {
case 512:
nand_chip->ecc.layout = &atmel_oobinfo_small;
ecc_writel(host->ecc, MR, ATMEL_ECC_PAGESIZE_528);
break;
case 1024:
nand_chip->ecc.layout = &atmel_oobinfo_large;
ecc_writel(host->ecc, MR, ATMEL_ECC_PAGESIZE_1056);
break;
case 2048:
nand_chip->ecc.layout = &atmel_oobinfo_large;
ecc_writel(host->ecc, MR, ATMEL_ECC_PAGESIZE_2112);
break;
case 4096:
nand_chip->ecc.layout = &atmel_oobinfo_large;
ecc_writel(host->ecc, MR, ATMEL_ECC_PAGESIZE_4224);
break;
default:
/* page size not handled by HW ECC */
/* switching back to soft ECC */
nand_chip->ecc.mode = NAND_ECC_SOFT;
nand_chip->ecc.calculate = NULL;
nand_chip->ecc.correct = NULL;
nand_chip->ecc.hwctl = NULL;
nand_chip->ecc.read_page = NULL;
nand_chip->ecc.postpad = 0;
nand_chip->ecc.prepad = 0;
nand_chip->ecc.bytes = 0;
break;
}
}

/* second phase scan */
if (nand_scan_tail(mtd)) {
res = -ENXIO;
goto err_scan_tail;
}

#ifdef CONFIG_MTD_PARTITIONS
#ifdef CONFIG_MTD_CMDLINE_PARTS
mtd->name = "atmel_nand";
num_partitions = parse_mtd_partitions(mtd, part_probes,
&partitions, 0);
#endif
if (num_partitions <= 0 && host->board->partition_info)
partitions = host->board->partition_info(mtd->size,
&num_partitions);

if ((!partitions) || (num_partitions == 0)) {
printk(KERN_ERR "atmel_nand: No parititions defined, or unsupported device.\n");
res = ENXIO;
goto err_no_partitions;
}

res = add_mtd_partitions(mtd, partitions, num_partitions);
#else
res = add_mtd_device(mtd);
#endif

if (!res)
return res;

#ifdef CONFIG_MTD_PARTITIONS
err_no_partitions:
#endif
nand_release(mtd);
err_scan_tail:
err_scan_ident:
err_no_card:
atmel_nand_disable(host);
platform_set_drvdata(pdev, NULL);
if (host->ecc)
iounmap(host->ecc);
err_ecc_ioremap:
iounmap(host->io_base);
err_nand_ioremap:
kfree(host);
return res;
}

/*
* Remove a NAND device.
*/
static int __exit atmel_nand_remove(struct platform_device *pdev)
{
struct atmel_nand_host *host = platform_get_drvdata(pdev);
struct mtd_info *mtd = &host->mtd;

nand_release(mtd);

atmel_nand_disable(host);

if (host->ecc)
iounmap(host->ecc);
iounmap(host->io_base);
kfree(host);

return 0;
}

static struct platform_driver atmel_nand_driver = {
.remove = __exit_p(atmel_nand_remove),
.driver = {
.name = "atmel_nand",
.owner = THIS_MODULE,
},
};

static int __init atmel_nand_init(void)
{
return platform_driver_probe(&atmel_nand_driver, atmel_nand_probe);
}

static void __exit atmel_nand_exit(void)
{
platform_driver_unregister(&atmel_nand_driver);
}

module_init(atmel_nand_init);
module_exit(atmel_nand_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Rick Bronson");
MODULE_DESCRIPTION("NAND/SmartMedia driver for AT91 / AVR32");
MODULE_ALIAS("platform:atmel_nand");