分类: LINUX
2009-03-25 16:43:13
Arm-linux东东nand之: s3c2410_nand_update_chip
先来看简单的s3c2410_nand_update_chip
static void s3c2410_nand_update_chip(struct s3c2410_nand_info *info,
struct s3c2410_nand_mtd *nmtd)
{
struct nand_chip *chip = &nmtd->chip;
printk("%s: chip %p: %d\n", __func__, chip, chip->page_shift);
if (hardware_ecc) {
/* change the behaviour depending on wether we are using
* the large or small page nand device */
if (chip->page_shift > 10) {
chip->ecc.size = 256;
chip->ecc.bytes = 3;
} else {
chip->ecc.size = 512;
chip->ecc.bytes = 3;
chip->ecc.layout = &nand_hw_eccoob;
}
}
}
这里跑出这么样的结构体:
/**
* struct nand_ecc_ctrl - Control structure for ecc
* @mode: ecc mode
* @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
* @prepad: padding information for syndrome based ecc generators
* @postpad: padding information for syndrome based ecc generators
* @layout: ECC layout control struct pointer
* @hwctl: function to control hardware ecc generator. Must only
* be 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)
* @read_page_raw: function to read a raw page without ECC
* @write_page_raw: function to write a raw page without ECC
* @read_page: function to read a page according to the ecc generator requirements
* @write_page: function to write a page according to the ecc generator requirements
* @read_oob: function to read chip OOB data
* @write_oob: function to write chip OOB data
*/
struct nand_ecc_ctrl {
nand_ecc_modes_t mode;
int steps;
int size;
int bytes;
int total;
int prepad;
int postpad;
struct nand_ecclayout *layout;
void (*hwctl)(struct mtd_info *mtd, int mode);
int (*calculate)(struct mtd_info *mtd,
const uint8_t *dat,
uint8_t *ecc_code);
int (*correct)(struct mtd_info *mtd, uint8_t *dat,
uint8_t *read_ecc,
uint8_t *calc_ecc);
int (*read_page_raw)(struct mtd_info *mtd,
struct nand_chip *chip,
uint8_t *buf);
void (*write_page_raw)(struct mtd_info *mtd,
struct nand_chip *chip,
const uint8_t *buf);
int (*read_page)(struct mtd_info *mtd,
struct nand_chip *chip,
uint8_t *buf);
void (*write_page)(struct mtd_info *mtd,
struct nand_chip *chip,
const uint8_t *buf);
int (*read_oob)(struct mtd_info *mtd,
struct nand_chip *chip,
int page,
int sndcmd);
int (*write_oob)(struct mtd_info *mtd,
struct nand_chip *chip,
int page);
};
好长呀.这里else语句会执行.
ecc.size就是计算一次ECC的时候的大小.什么意思呀>>
举个例子.我的硬件没有那么高级.只能算256个Byte的ECC.那512是不是要分两次来发送.不然的话我没有办法计算.
ecc.bytes就是算一次ECC有多少字节.不同的算法有不同的ECC长度.这个好理解.
static struct nand_ecclayout nand_hw_eccoob = {
.eccbytes = 3,
.eccpos = {0, 1, 2},
.oobfree = {{8, 8}}
};
这个用到再说.反正就是一些值.
这个函数就这样了.