[UBOOT] AM335x nand init/nand command trace（u-boot-2011.09）

最新推荐文章于 2021-05-07 09:41:47 发布

psvoldemort

最新推荐文章于 2021-05-07 09:41:47 发布

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分类专栏：项目-AM335x

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本文详细介绍了NAND闪存设备的初始化过程及各种关键操作实现，包括读写、擦除、坏块标记等，并深入探讨了硬件ECC校验机制的配置。

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nand_init();//nand.c
			nand_init_chip
				int board_nand_init(struct nand_chip *nand);//初始化nand_chip
					ti81xx_nand_switch_ecc(NAND_ECC_HW, 2);
						__ti81xx_nand_switch_ecc
							nand->ecc.bytes = 14;
							nand->ecc.layout = &hw_bch8_nand_oob;
							bch->nibbles = ECC_BCH8_NIBBLES;
							
							bch->mode = NAND_ECC_HW;
							nand->ecc.mode = NAND_ECC_HW_SYNDROME;
							nand->ecc.steps = 4;
							nand->ecc.size = 512;
							nand->ecc.total = (nand->ecc.steps * nand->ecc.bytes);
							nand->ecc.write_page = ti81xx_write_page_bch;
							nand->ecc.read_page = ti81xx_read_page_bch;
							nand->ecc.hwctl = ti81xx_enable_ecc_bch;
							nand->ecc.correct = ti81xx_correct_data_bch;
							nand->ecc.calculate = ti81xx_calculate_ecc_bch;
							
							ti81xx_hwecc_init_bch(nand, NAND_ECC_READ);
								nand->options |= NAND_OWN_BUFFERS;
						nand_scan_tail(mtd);
							//初始化阶段，在这里调用的nand_scan_tail本质上没有作用，直接返回(因为在ti81xx_hwecc_init_bch设置了NAND_OWN_BUFFERS)						
						nand->options &= ~NAND_OWN_BUFFERS;
			
							
				nand_scan
					nand_scan_ident
						nand_set_defaults
							chip->cmdfunc = nand_command;//这时还是小页的nand_command
						nand_get_flash_type
							chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1);//READID
							*maf_id = chip->read_byte(mtd);//1st MID
							*dev_id = chip->read_byte(mtd);//2nd PID
							nand_flash_detect_onfi//不支持onfi，直接返回0；
								chip->cmdfunc(mtd, NAND_CMD_READID, 0x20, -1);//READID,ONFI
								read_byte //4个周期 O、N、F、I
								chip->cmdfunc(mtd, NAND_CMD_PARAM, 0, -1);
								chip->read_buf(mtd, (uint8_t *)p, sizeof(*p));//读nand_onfi_params结构体
							nand_flash_detect_non_onfi//readid 3rd/4th个周期
							
							if (mtd->writesize > 512 && chip->cmdfunc == nand_command)
								chip->cmdfunc = nand_command_lp;
					nand_scan_tail
						chip->write_page = nand_write_page;
							
						/* Fill in remaining MTD driver data */
						mtd->type = MTD_NANDFLASH;
						mtd->flags = MTD_CAP_NANDFLASH;
						mtd->erase = nand_erase;
						mtd->point = NULL;
						mtd->unpoint = NULL;
						mtd->read = nand_read;
						mtd->write = nand_write;
						mtd->read_oob = nand_read_oob;
						mtd->write_oob = nand_write_oob;
						mtd->sync = nand_sync;
						mtd->lock = NULL;
						mtd->unlock = NULL;
						mtd->block_isbad = nand_block_isbad;
						mtd->block_markbad = nand_block_markbad;



nand dump
	do_nand
		nand_dump
			ops.mode = MTD_OOB_RAW;
			i = nand->read_oob(nand, addr, &ops);=nand_read_oob
				nand_do_read_ops
					chip->cmdfunc(mtd, NAND_CMD_READ0, 0x00, page);
					
					if (unlikely(ops->mode == MTD_OOB_RAW))
					ret = chip->ecc.read_page_raw(mtd, chip,bufpoi, page);=nand_read_page_raw,没有ECC保护
						chip->read_buf(mtd, buf, mtd->writesize);//读data
						chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);//读oob
					
					
nand read
	do_nand
		nand_read_skip_bad(nand, off, &rwsize,(u_char *)addr)
			check_skip_len
				int nand_block_isbad(struct mtd_info *mtd, loff_t offs)	
					int nand_block_isbad(struct mtd_info *mtd, loff_t offs)
						chip->block_bad;=nand_block_bad	
							chip->cmdfunc(mtd, NAND_CMD_READOOB, chip->badblockpos, page);
							chip->read_byte(mtd) != 0xff
							
			nand_read (nand, offset, length, buffer);
				nand_do_read_ops
					chip->cmdfunc(mtd, NAND_CMD_READ0, 0x00, page);//READ0命令，随机读之前需要发送
					ret = chip->ecc.read_page(mtd, chip, bufpoi, page);=ti81xx_read_page_bch//随机读
						
						
nand write
	do_nand
		nand_write_skip_bad(nand, off, &rwsize,(u_char *)addr, 0);		
			check_skip_len
			nand_write (nand, offset, length, buffer);	
				nand_do_write_ops
					chip->write_page(mtd, chip, wbuf, page, cached,(ops->mode == MTD_OOB_RAW));=nand_write_page
						chip->cmdfunc(mtd, NAND_CMD_SEQIN, 0x00, page);
						chip->ecc.write_page(mtd, chip, buf);=ti81xx_write_page_bch
						
						
nand erase
	do_nand
		nand_erase_opts(nand, &opts);
			nand_erase
				nand_erase_nand
					chip->erase_cmd(mtd, page & chip->pagemask);=single_erase_cmd
						chip->cmdfunc(mtd, NAND_CMD_ERASE1, -1, page);
						chip->cmdfunc(mtd, NAND_CMD_ERASE2, -1, -1);
					status = chip->waitfunc(mtd, chip);=nand_wait
						this->cmdfunc(mtd, NAND_CMD_STATUS, -1, -1);
						return this->read_byte(mtd);
					
nand markbad
	do_nand
		nand->block_markbad(nand, addr);=nand_block_markbad//mtd_info
			chip->block_markbad(mtd, ofs);=nand_default_block_markbad//nand_chip
				nand_do_write_oob
					nand_fill_oob(chip, ops->oobbuf, ops);
					status = chip->ecc.write_oob(mtd, chip, page & chip->pagemask);=nand_write_oob_std