도와주세요!!
/dev 폴더에 있는 node파일 중에서 어떤 것을 open해야 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 <linux/slab.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/nand.h>
#include <linux/mtd/partitions.h>
#include <linux/gpio.h>
#include <linux/io.h>
#include <mach/board.h>
#include <mach/cpu.h>
#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");
저는 단순히 nand flash에 데이터를 넣고 지웠다가 쓰는 정도로 데이터 저장용으로 우선 테스트 좀 해볼려구여 ^^;
rootfs가 jffs나 ubifs로 된 flash filesystem 아니신지...
그게 맞다면...
님께서 고민하시는 부분은..
마치..
PC에서 하드디스크를 직접 제어하여 데이터를 넣고 지웠다 하는 저장용도로 사용하시려는 상황 같은데요.
OS가 하드디스크를 드라이버부터 파일시스템layer까지 다 해주는 상황에서
오픈된 OS소스에 hdd 초기화코드 및 제어하는 코드가 보이므로 직접 제어하고자 하는 그런 상황??
맞나 모르네요^^
raw로 data를 쓰고자 한다면
cat /proc/mtd 하시면
mtd 파티션상황이 보일테고
사용하지 않는 파티션에 쓰면 될듯 하네요.. mtd에 직접 data를 밀어넣는 방법은 구박사님(google)에게...
nand flash를 어떤용도로 사용하실건지..
mtd로 마운트시켜서 사용하지 않고 raw로 직접 사용하실건지요.
디스크처럼 사용하지 않으실거면.....