在已有8bit NANDFlash控制器驱动的基础上，添加16bit NANDFlash需要关注board.c中.name和.id的更新，以及nand_flash_ids[]表的配置。启动时，kernel通过nand_scan()来识别和配置新添加的NANDFlash，该函数会根据bus宽度和maf_id进行操作。
已经有nandflash controller的驱动了，但是要添加一个新的nandflash，尤其是本来是8bit， 新加的是16bit时，需要注意如下：
1. board.c 中：
static struct platform_nand_data cartesio_nand_mlc_data = {
.chip = {
.nr_chips = 1, /* 1 NAND chip per FSMC NAND-Flash slot */
.chip_offset = 0, /* using FSMC PC-Card/NAND-Flash slot 0 */
.nr_partitions = ARRAY_SIZE(cartesio_nand_mlc_partitions),
.partitions = cartesio_nand_mlc_partitions,
.ecclayout = &cartesio_nand_mlc_ecclayout,
.chip_delay = 20,
.options = NAND_BUSWIDTH_16, //这里8bit时是0，使用16bit时，应该修改
},
#ifdef CONFIG_CARTESIO_NAND_DMA
.ctrl = {
.priv = &cartesio_dma_nand,
}
#endif
};同时需要注意下面的 .name 和 .id， nand_base.c 中的驱动会用到。
static struct platform_device cartesio_nand_mlc_flash = {
.name = "CARTESIO-NAND", // 这个会用来判断是不是NULL
.id = 0, // id会用来比较 chip id
.dev = {
.platform_data = &cartesio_nand_mlc_data,
.parent = &fsmc_device.dev,
},
.num_resources = ARRAY_SIZE(cartesio_nand_mlc_resource),
.resource = cartesio_nand_mlc_resource,
};这里有个表 nand_flash_ids[]， 定义如下：
/*
* Chip ID list
*
* Name. ID code, pagesize, chipsize in MegaByte, eraseblock size,
* options
*
* Pagesize; 0, 256, 512
* 0 get this information from the extended chip ID
+ 256 256 Byte page size
* 512 512 Byte page size
*/
struct nand_flash_dev nand_flash_ids[] = {
#ifdef CONFIG_MTD_NAND_MUSEUM_IDS
{"NAND 1MiB 5V 8-bit", 0x6e, 256, 1, 0x1000, 0},
{"NAND 2MiB 5V 8-bit", 0x64, 256, 2, 0x1000, 0},
{"NAND 4MiB 5V 8-bit", 0x6b, 512, 4, 0x2000, 0},
{"NAND 1MiB 3,3V 8-bit", 0xe8, 256, 1, 0x1000, 0},
{"NAND 1MiB 3,3V 8-bit", 0xec, 256, 1, 0x1000, 0},
{"NAND 2MiB 3,3V 8-bit", 0xea, 256, 2, 0x1000, 0},
{"NAND 4MiB 3,3V 8-bit", 0xd5, 512, 4, 0x2000, 0},
{"NAND 4MiB 3,3V 8-bit", 0xe3, 512, 4, 0x2000, 0},
{"NAND 4MiB 3,3V 8-bit", 0xe5, 512, 4, 0x2000, 0},
{"NAND 8MiB 3,3V 8-bit", 0xd6, 512, 8, 0x2000, 0},
{"NAND 8MiB 1,8V 8-bit", 0x39, 512, 8, 0x2000, 0},
{"NAND 8MiB 3,3V 8-bit", 0xe6, 512, 8, 0x2000, 0},
{"NAND 8MiB 1,8V 16-bit", 0x49, 512, 8, 0x2000, NAND_BUSWIDTH_16},
{"NAND 8MiB 3,3V 16-bit", 0x59, 512, 8, 0x2000, NAND_BUSWIDTH_16},
#endif
{"NAND 16MiB 1,8V 8-bit", 0x33, 512, 16, 0x4000, 0},
{"NAND 16MiB 3,3V 8-bit", 0x73, 512, 16, 0x4000, 0},
{"NAND 16MiB 1,8V 16-bit", 0x43, 512, 16, 0x4000, NAND_BUSWIDTH_16},
{"NAND 16MiB 3,3V 16-bit", 0x53, 512, 16, 0x4000, NAND_BUSWIDTH_16},
{"NAND 32MiB 1,8V 8-bit", 0x35, 512, 32, 0x4000, 0},
{"NAND 32MiB 3,3V 8-bit", 0x75, 512, 32, 0x4000, 0},
{"NAND 32MiB 1,8V 16-bit", 0x45, 512, 32, 0x4000, NAND_BUSWIDTH_16},
{"NAND 32MiB 3,3V 16-bit", 0x55, 512, 32, 0x4000, NAND_BUSWIDTH_16},
{"NAND 64MiB 1,8V 8-bit", 0x36, 512, 64, 0x4000, 0},
{"NAND 64MiB 3,3V 8-bit", 0x76, 512, 64, 0x4000, 0},
{"NAND 64MiB 1,8V 16-bit", 0x46, 512, 64, 0x4000, NAND_BUSWIDTH_16},
{"NAND 64MiB 3,3V 16-bit", 0x56, 512, 64, 0x4000, NAND_BUSWIDTH_16},
{"NAND 128MiB 1,8V 8-bit", 0x78, 512, 128, 0x4000, 0},
{"NAND 128MiB 1,8V 8-bit", 0x39, 512, 128, 0x4000, 0},
{"NAND 128MiB 3,3V 8-bit", 0x79, 512, 128, 0x4000, 0},
{"NAND 128MiB 1,8V 16-bit", 0x72, 512, 128, 0x4000, NAND_BUSWIDTH_16},
{"NAND 128MiB 1,8V 16-bit", 0x49, 512, 128, 0x4000, NAND_BUSWIDTH_16},
{"NAND 128MiB 3,3V 16-bit", 0x74, 512, 128, 0x4000, NAND_BUSWIDTH_16},
{"NAND 128MiB 3,3V 16-bit", 0x59, 512, 128, 0x4000, NAND_BUSWIDTH_16},
{"NAND 256MiB 3,3V 8-bit", 0x71, 512, 256, 0x4000, 0},
/*
* These are the new chips with large page size. The pagesize and the
* erasesize is determined from the extended id bytes
*/
#define LP_OPTIONS (NAND_SAMSUNG_LP_OPTIONS | NAND_NO_READRDY | NAND_NO_AUTOINCR)
#define LP_OPTIONS16 (LP_OPTIONS | NAND_BUSWIDTH_16)
/*512 Megabit */
{"NAND 64MiB 1,8V 8-bit", 0xA2, 0, 64, 0, LP_OPTIONS},
{"NAND 64MiB 3,3V 8-bit", 0xF2, 0, 64, 0, LP_OPTIONS},
{"NAND 64MiB 1,8V 16-bit", 0xB2, 0, 64, 0, LP_OPTIONS16},
{"NAND 64MiB 3,3V 16-bit", 0xC2, 0, 64, 0, LP_OPTIONS16},
/* 1 Gigabit */
{"NAND 128MiB 1,8V 8-bit", 0xA1, 0, 128, 0, LP_OPTIONS},
{"NAND 128MiB 3,3V 8-bit", 0xF1, 0, 128, 0, LP_OPTIONS},
{"NAND 128MiB 1,8V 16-bit", 0xB1, 0, 128, 0, LP_OPTIONS16},
{"NAND 128MiB 3,3V 16-bit", 0xC1, 0, 128, 0, LP_OPTIONS16},
/* 2 Gigabit */
{"NAND 256MiB 1,8V 8-bit", 0xAA, 0, 256, 0, LP_OPTIONS},
{"NAND 256MiB 3,3V 8-bit", 0xDA, 0, 256, 0, LP_OPTIONS},
{"NAND 256MiB 1,8V 16-bit", 0xBA, 0, 256, 0, LP_OPTIONS16},
{"NAND 256MiB 3,3V 16-bit", 0xCA, 0, 256, 0, LP_OPTIONS16},
/* 4 Gigabit */
{"NAND 512MiB 1,8V 8-bit", 0xAC, 0, 512, 0, LP_OPTIONS},
{"NAND 512MiB 3,3V 8-bit", 0xDC, 0, 512, 0, LP_OPTIONS},
{"NAND 512MiB 1,8V 16-bit", 0xBC, 0, 512, 0, LP_OPTIONS16},
{"NAND 512MiB 3,3V 16-bit", 0xCC, 0, 512, 0, LP_OPTIONS16},
/* 8 Gigabit */
{"NAND 1GiB 1,8V 8-bit", 0xA3, 0, 1024, 0, LP_OPTIONS},
{"NAND 1GiB 3,3V 8-bit", 0xD3, 0, 1024, 0, LP_OPTIONS},
{"NAND 1GiB 1,8V 16-bit", 0xB3, 0, 1024, 0, LP_OPTIONS16},
{"NAND 1GiB 3,3V 16-bit", 0xC3, 0, 1024, 0, LP_OPTIONS16},
/* 16 Gigabit */
{"NAND 2GiB 1,8V 8-bit", 0xA5, 0, 2048, 0, LP_OPTIONS},
{"NAND 2GiB 3,3V 8-bit", 0xD5, 0, 2048, 0, LP_OPTIONS},
{"NAND 2GiB 1,8V 16-bit", 0xB5, 0, 2048, 0, LP_OPTIONS16},
{"NAND 2GiB 3,3V 16-bit", 0xC5, 0, 2048, 0, LP_OPTIONS16},
/*Board specific ifdef for mlc nand onfi standard support*/
#ifdef CONFIG_BCH_8
{"NAND 2GiB 3,3V 8-bit", 0x48, 4096, 2048, 0x100000, 0},
{"NAND 256MiB 3,3V 16-bit", 0x90, 1024, 256, 0x20000, NAND_BUSWIDTH_16},
#endif
/*
* Renesas AND 1 Gigabit. Those chips do not support extended id and
* have a strange page/block layout ! The chosen minimum erasesize is
* 4 * 2 * 2048 = 16384 Byte, as those chips have an array of 4 page
* planes 1 block = 2 pages, but due to plane arrangement the blocks
* 0-3 consists of page 0 + 4,1 + 5, 2 + 6, 3 + 7 Anyway JFFS2 would
* increase the eraseblock size so we chose a combined one which can be
* erased in one go There are more speed improvements for reads and
* writes possible, but not implemented now
*/
{"AND 128MiB 3,3V 8-bit", 0x01, 2048, 128, 0x4000,
NAND_IS_AND | NAND_NO_AUTOINCR |NAND_NO_READRDY | NAND_4PAGE_ARRAY |
BBT_AUTO_REFRESH
},
{NULL,}
};/**
* struct nand_flash_dev - NAND Flash Device ID Structure
* @name: Identify the device type
* @id: device ID code
* @pagesize: Pagesize in bytes. Either 256 or 512 or 0
* If the pagesize is 0, then the real pagesize
* and the eraseize are determined from the
* extended id bytes in the chip
* @erasesize: Size of an erase block in the flash device.
* @chipsize: Total chipsize in Mega Bytes
* @options: Bitfield to store chip relevant options
*/
struct nand_flash_dev {
char *name;
int id;
unsigned long pagesize; //页大小
unsigned long chipsize; //nand整个大小
unsigned long erasesize; //擦写大小，基本就是指块（block）大小
unsigned long options; //bus width，
};kernel 启动后，加载nandflash时， 首先调用 nand_scan()
/**
* nand_scan - [NAND Interface] Scan for the NAND device
* @mtd: MTD device structure
* @maxchips: Number of chips to scan for
*
* This fills out all the uninitialized function pointers
* with the defaults.
* The flash ID is read and the mtd/chip structures are
* filled with the appropriate values.
* The mtd->owner field must be set to the module of the caller
*
*/
int nand_scan(struct mtd_info *mtd, int maxchips)
{
int ret;
/* Many callers got this wrong, so check for it for a while... */
if (!mtd->owner && caller_is_module()) {
printk(KERN_CRIT "%s called with NULL mtd->owner!\n",
__func__);
BUG();
}
ret = nand_scan_ident(mtd, maxchips); //这里主要是调用这函数
if (!ret)
ret = nand_scan_tail(mtd);
return ret;
}/**
* nand_scan_ident - [NAND Interface] Scan for the NAND device
* @mtd: MTD device structure
* @maxchips: Number of chips to scan for
*
* This is the first phase of the normal nand_scan() function. It
* reads the flash ID and sets up MTD fields accordingly.
*
* The mtd->owner field must be set to the module of the caller.
*/
int nand_scan_ident(struct mtd_info *mtd, int maxchips)
{
int i, busw, nand_maf_id;
struct nand_chip *chip = mtd->priv;
struct nand_flash_dev *type;
/* Get buswidth to select the correct functions */
busw = chip->options & NAND_BUSWIDTH_16;
/* Set the default functions */
nand_set_defaults(chip, busw);
/* Read the flash type */
type = nand_get_flash_type(mtd, chip, busw, &nand_maf_id); //这里主要是调用这个函数，识别nand的类型，如果没识别，则下面返回 No NAND..
if (IS_ERR(type)) {
if (!(chip->options & NAND_SCAN_SILENT_NODEV))
printk(KERN_WARNING "No NAND device found.\n"); //这里如果没有探测到nand， 会打印这个log
chip->select_chip(mtd, -1);
return PTR_ERR(type);
}
/* Check for a chip array */
for (i = 1; i < maxchips; i++) {
chip->select_chip(mtd, i);
/* See comment in nand_get_flash_type for reset */
chip->cmdfunc(mtd, NAND_CMD_RESET, -1, -1);
/* Send the command for reading device ID */
chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1);
/* Read manufacturer and device IDs */
if (nand_maf_id != chip->read_byte(mtd) ||
type->id != chip->read_byte(mtd))
break;
}
if (i > 1)
printk(KERN_INFO "%d NAND chips detected\n", i); //如果多个nand探测到，会打印这个log
/* Store the number of chips and calc total size for mtd */
chip->numchips = i;
mtd->size = i * chip->chipsize;
return 0;
}struct nand_chip *chip,
int busw, int *maf_id)
定义如下：
/*
* Get the flash and manufacturer id and lookup if the type is supported
*/
static struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
struct nand_chip *chip,
int busw, int *maf_id)
{
struct nand_flash_dev *type = NULL;
int i, dev_id, maf_idx;
int tmp_id, tmp_manf;
/* Select the device */
chip->select_chip(mtd, 0);
/*
* Reset the chip, required by some chips (e.g. Micron MT29FxGxxxxx)
* after power-up
*/
chip->cmdfunc(mtd, NAND_CMD_RESET, -1, -1);
/* Send the command for reading device ID */
chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1);
/* Read manufacturer and device IDs */
*maf_id = chip->read_byte(mtd);
dev_id = chip->read_byte(mtd); //这里获得 dev_id 设备ID。
/* Try again to make sure, as some systems the bus-hold or other
* interface concerns can cause random data which looks like a
* possibly credible NAND flash to appear. If the two results do
* not match, ignore the device completely.
*/
chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1);
/* Read manufacturer and device IDs */
tmp_manf = chip->read_byte(mtd);
tmp_id = chip->read_byte(mtd);
if (tmp_manf != *maf_id || tmp_id != dev_id) {
printk(KERN_INFO "%s: second ID read did not match "
"%02x,%02x against %02x,%02x\n", __func__,
*maf_id, dev_id, tmp_manf, tmp_id);
return ERR_PTR(-ENODEV);
}
printk(KERN_INFO "dev_id = 0x%x", dev_id); //这是我添加的打印，为了打印出设备id
/* Lookup the flash id */
for (i = 0; nand_flash_ids[i].name != NULL; i++) { //这里如果board.c 中有定义nand设备，且.name != NULL,
if (dev_id == nand_flash_ids[i].id) { //就会开始遍历 nand_flash_ids[] 设备表，进行匹配，如果有设备id相同
type = &nand_flash_ids[i]; //就是给type进行赋值
break;
}
}
if (!type)
return ERR_PTR(-ENODEV);
if (!mtd->name)
mtd->name = type->name;
chip->chipsize = (uint64_t)type->chipsize << 20;
/* Newer devices have all the information in additional id bytes */
if (!type->pagesize) {
int extid;
/* The 3rd id byte holds MLC / multichip data */
chip->cellinfo = chip->read_byte(mtd);
/* The 4th id byte is the important one */
extid = chip->read_byte(mtd);
/* Calc pagesize */
mtd->writesize = 1024 << (extid & 0x3);
extid >>= 2;
/* Calc oobsize */
mtd->oobsize = (8 << (extid & 0x01)) * (mtd->writesize >> 9);
extid >>= 2;
/* Calc blocksize. Blocksize is multiples of 64KiB */
mtd->erasesize = (64 * 1024) << (extid & 0x03);
extid >>= 2;
/* Get buswidth information */
busw = (extid & 0x01) ? NAND_BUSWIDTH_16 : 0;
} else {
/*
* Old devices have chip data hardcoded in the device id table
*/
mtd->erasesize = type->erasesize;
mtd->writesize = type->pagesize;
/*Board specific ifdef for greater than 128 oobsize*/
#ifdef CONFIG_BCH_8
mtd->oobsize = 224;
#else
mtd->oobsize = mtd->writesize / 32;
#endif
busw = type->options & NAND_BUSWIDTH_16;
}
/* Try to identify manufacturer */
for (maf_idx = 0; nand_manuf_ids[maf_idx].id != 0x0; maf_idx++) {
if (nand_manuf_ids[maf_idx].id == *maf_id)
break;
}
/*
* Check, if buswidth is correct. Hardware drivers should set
* chip correct !
*/
if (busw != (chip->options & NAND_BUSWIDTH_16)) { //如果 buswidth 不对，会打印如下log
printk(KERN_INFO "NAND device: Manufacturer ID:"
" 0x%02x, Chip ID: 0x%02x (%s %s)\n", *maf_id,
dev_id, nand_manuf_ids[maf_idx].name, mtd->name);
printk(KERN_WARNING "NAND bus width %d instead %d bit\n",
(chip->options & NAND_BUSWIDTH_16) ? 16 : 8,
busw ? 16 : 8);
return ERR_PTR(-EINVAL);
}
/* Calculate the address shift from the page size */
chip->page_shift = ffs(mtd->writesize) - 1;
/* Convert chipsize to number of pages per chip -1. */
chip->pagemask = (chip->chipsize >> chip->page_shift) - 1;
chip->bbt_erase_shift = chip->phys_erase_shift =
ffs(mtd->erasesize) - 1;
if (chip->chipsize & 0xffffffff)
chip->chip_shift = ffs((unsigned)chip->chipsize) - 1;
else
chip->chip_shift = ffs((unsigned)(chip->chipsize >> 32)) + 32 - 1;
/* Set the bad block position */
chip->badblockpos = mtd->writesize > 512 ?
NAND_LARGE_BADBLOCK_POS : NAND_SMALL_BADBLOCK_POS;
/* Get chip options, preserve non chip based options */
chip->options &= ~NAND_CHIPOPTIONS_MSK;
chip->options |= type->options & NAND_CHIPOPTIONS_MSK;
/*
* Set chip as a default. Board drivers can override it, if necessary
*/
chip->options |= NAND_NO_AUTOINCR;
/* Check if chip is a not a samsung device. Do not clear the
* options for chips which are not having an extended id.
*/
if (*maf_id != NAND_MFR_SAMSUNG && !type->pagesize)
chip->options &= ~NAND_SAMSUNG_LP_OPTIONS;
/* Check for AND chips with 4 page planes */
if (chip->options & NAND_4PAGE_ARRAY)
chip->erase_cmd = multi_erase_cmd;
else
chip->erase_cmd = single_erase_cmd;
/* Do not replace user supplied command function ! */
if (mtd->writesize > 512 && chip->cmdfunc == nand_command)
chip->cmdfunc = nand_command_lp;
printk(KERN_INFO "NAND device: Manufacturer ID:" //如果最终探测出nandflash，会打印这个
" 0x%02x, Chip ID: 0x%02x (%s %s)\n", *maf_id, dev_id,
nand_manuf_ids[maf_idx].name, type->name);
return type;
}
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