uboot之nand flash相关(1)

这几天在做和nandflash相关的东西，之前uboot中nandflash部分搞得模模糊糊。这次就将uboot中nand flash相关部分分析清楚

。本文uboot版本1.3.3

按照uboot的执行流程，在lib_arm/board.c文件中的start_armboot函数中会调用到nand初始化。

初始化的调用流程大致为：

start_armboot

nand_init //driver/mtd/nand/nand.c

nand_init_chip //driver/mtd/nand/nand.c

board_nand_init //cpu/sep4020/nand_flash.c

nand_scan //driver/mtd/nand/nand_base.c

start_armboot函数中，nand初始化部分

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1. #if defined(CONFIG_CMD_NAND) /*有nand的板都会定义CONFIG_CMD_NAND*/
   
2. puts ("NAND: ");
   
3. nand_init(); /* go init the NAND */
   
4. #endif

nand_init()在driver/mtd/nand/nand.c文件中定义,此为nand初始化入口函数。

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1. void nand_init(void)
   
2. {
   
3. int i;
   
4. unsigned int size = 0;
   
5. for (i = 0; i < CFG_MAX_NAND_DEVICE; i++) { //(1)
   
6. nand_init_chip(&nand_info[i], &nand_chip[i], base_address[i]); //(2)
   
7. size += nand_info[i].size; //(3)
   
8. if (nand_curr_device == -1)
   
9. nand_curr_device = i;
   
10. }
    
11. printf("%lu MiB\n", size / (1024 * 1024));
    
12. 
    
13. #ifdef CFG_NAND_SELECT_DEVICE
    
14. /*
    
15. * Select the chip in the board/cpu specific driver
    
16. */
    
17. board_nand_select_device(nand_info[nand_curr_device].priv, nand_curr_device);
    
18. #endif
    
19. }

(1)CFG_MAX_NAND_DEVICE，nand的数量，一般板上有一个nand，就定义为1

(2)此函数初始化一个nand flash。首先看函数参数的3个变量。

参数1 nand_info[i],其定义如

nand_info_t nand_info[CFG_MAX_NAND_DEVICE]; //driver/mtd/nand/nand.c

定义了一个nand_info_t类型的全局数组，当然这里其CFG_MAX_NAND_DEVICE等于1，只有一个成员，再看nand_info_t定义

typedef struct mtd_info nand_info_t; //include/Nand.h

mtd_info定义在include/linux/mtd/mtd.h中，它表示一个mtd设备的结构体，包含了mtd属性和其操作函数。

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1. struct mtd_info {
   
2. u_char type;
   
3. u_int32_t flags;
   
4. u_int32_t size; /* Total size of the MTD */
   
5. 
   
6. /* "Major" erase size for the device. Na飗e users may take this
   
7. * to be the only erase size available, or may use the more detailed
   
8. * information below if they desire
   
9. */
   
10. u_int32_t erasesize;
    
11. 
    
12. u_int32_t oobblock; /* Size of OOB blocks (e.g. 512) */
    
13. u_int32_t oobsize; /* Amount of OOB data per block (e.g. 16) */
    
14. u_int32_t oobavail; /* Number of bytes in OOB area available for fs */
    
15. u_int32_t ecctype;
    
16. u_int32_t eccsize;
    
17. 
    
18. 
    
19. /* Kernel-only stuff starts here. */
    
20. char *name;
    
21. int index;
    
22. 
    
23. /* oobinfo is a nand_oobinfo structure, which can be set by iotcl (MEMSETOOBINFO) */
    
24. struct nand_oobinfo oobinfo;
    
25. 
    
26. /* Data for variable erase regions. If numeraseregions is zero,
    
27. * it means that the whole device has erasesize as given above.
    
28. */
    
29. int numeraseregions;
    
30. struct mtd_erase_region_info *eraseregions;
    
31. 
    
32. /* This really shouldn't be here. It can go away in 2.5 */
    
33. u_int32_t bank_size;
    
34. 
    
35. int (*erase) (struct mtd_info *mtd, struct erase_info *instr);
    
36. 
    
37. /* This stuff for eXecute-In-Place */
    
38. int (*point) (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char **mtdbuf);
    
39. 
    
40. /* We probably shouldn't allow XIP if the unpoint isn't a NULL */
    
41. void (*unpoint) (struct mtd_info *mtd, u_char * addr, loff_t from, size_t len);
    
42. 
    
43. 
    
44. int (*read) (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf);
    
45. int (*write) (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf);
    
46. 
    
47. int (*read_ecc) (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf, u_char
    
48. 
    
49. *eccbuf, struct nand_oobinfo *oobsel);
    
50. int (*write_ecc) (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf, u_char
    
51. 
    
52. *eccbuf, struct nand_oobinfo *oobsel);
    
53. 
    
54. int (*read_oob) (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf);
    
55. int (*write_oob) (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf);
    
56. 
    
57. /*
    
58. * Methods to access the protection register area, present in some
    
59. * flash devices. The user data is one time programmable but the
    
60. * factory data is read only.
    
61. */
    
62. int (*read_user_prot_reg) (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf);
    
63. 
    
64. int (*read_fact_prot_reg) (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf);
    
65. 
    
66. /* This function is not yet implemented */
    
67. int (*write_user_prot_reg) (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf);
    
68. 
    
69. /* Sync */
    
70. void (*sync) (struct mtd_info *mtd);
    
71. 
    
72. /* Bad block management functions */
    
73. int (*block_isbad) (struct mtd_info *mtd, loff_t ofs);
    
74. int (*block_markbad) (struct mtd_info *mtd, loff_t ofs);
    
75. 
    
76. void *priv;
    
77. 
    
78. struct module *owner;
    
79. int usecount;
    
80. };

参数2 nand_chip[i] ，如下

static struct nand_chip nand_chip[CFG_MAX_NAND_DEVICE];

再看struct nand_chip定义，当前文件（driver/mtd/nand/nand.c）包含nand.h(include目录)，nand.h又包含#include <linux/mtd/nand.h>，所以nand_chip的定义是linux/mtd/nand.h中的。不是nand_legacy.h。这个结构体表示一个nand flash其包含所有属性和操作函数。

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1. /**
   
2. * struct nand_chip - NAND Private Flash Chip Data
   
3. * @IO_ADDR_R: [BOARDSPECIFIC] address to read the 8 I/O lines of the flash device
   
4. * @IO_ADDR_W: [BOARDSPECIFIC] address to write the 8 I/O lines of the flash device
   
5. * @read_byte: [REPLACEABLE] read one byte from the chip
   
6. * @write_byte: [REPLACEABLE] write one byte to the chip
   
7. * @read_word: [REPLACEABLE] read one word from the chip
   
8. * @write_word: [REPLACEABLE] write one word to the chip
   
9. * @write_buf: [REPLACEABLE] write data from the buffer to the chip
   
10. * @read_buf: [REPLACEABLE] read data from the chip into the buffer
    
11. * @verify_buf: [REPLACEABLE] verify buffer contents against the chip data
    
12. * @select_chip: [REPLACEABLE] select chip nr
    
13. * @block_bad: [REPLACEABLE] check, if the block is bad
    
14. * @block_markbad: [REPLACEABLE] mark the block bad
    
15. * @hwcontrol: [BOARDSPECIFIC] hardwarespecific function for accesing control-lines
    
16. * @dev_ready: [BOARDSPECIFIC] hardwarespecific function for accesing device ready/busy line
    
17. * If set to NULL no access to ready/busy is available and the ready/busy information
    
18. * is read from the chip status register
    
19. * @cmdfunc: [REPLACEABLE] hardwarespecific function for writing commands to the chip
    
20. * @waitfunc: [REPLACEABLE] hardwarespecific function for wait on ready
    
21. * @calculate_ecc: [REPLACEABLE] function for ecc calculation or readback from ecc hardware
    
22. * @correct_data: [REPLACEABLE] function for ecc correction, matching to ecc generator (sw/hw)
    
23. * @enable_hwecc: [BOARDSPECIFIC] function to enable (reset) hardware ecc generator. Must only
    
24. * be provided if a hardware ECC is available
    
25. * @erase_cmd: [INTERN] erase command write function, selectable due to AND support
    
26. * @scan_bbt: [REPLACEABLE] function to scan bad block table
    
27. * @eccmode: [BOARDSPECIFIC] mode of ecc, see defines
    
28. * @eccsize: [INTERN] databytes used per ecc-calculation
    
29. * @eccbytes: [INTERN] number of ecc bytes per ecc-calculation step
    
30. * @eccsteps: [INTERN] number of ecc calculation steps per page
    
31. * @chip_delay: [BOARDSPECIFIC] chip dependent delay for transfering data from array to read regs (tR)
    
32. * @chip_lock: [INTERN] spinlock used to protect access to this structure and the chip
    
33. * @wq: [INTERN] wait queue to sleep on if a NAND operation is in progress
    
34. * @state: [INTERN] the current state of the NAND device
    
35. * @page_shift: [INTERN] number of address bits in a page (column address bits)
    
36. * @phys_erase_shift: [INTERN] number of address bits in a physical eraseblock
    
37. * @bbt_erase_shift: [INTERN] number of address bits in a bbt entry
    
38. * @chip_shift: [INTERN] number of address bits in one chip
    
39. * @data_buf: [INTERN] internal buffer for one page + oob
    
40. * @oob_buf: [INTERN] oob buffer for one eraseblock
    
41. * @oobdirty: [INTERN] indicates that oob_buf must be reinitialized
    
42. * @data_poi: [INTERN] pointer to a data buffer
    
43. * @options: [BOARDSPECIFIC] various chip options. They can partly be set to inform nand_scan about
    
44. * special functionality. See the defines for further explanation
    
45. * @badblockpos: [INTERN] position of the bad block marker in the oob area
    
46. * @numchips: [INTERN] number of physical chips
    
47. * @chipsize: [INTERN] the size of one chip for multichip arrays
    
48. * @pagemask: [INTERN] page number mask = number of (pages / chip) - 1
    
49. * @pagebuf: [INTERN] holds the pagenumber which is currently in data_buf
    
50. * @autooob: [REPLACEABLE] the default (auto)placement scheme
    
51. * @bbt: [INTERN] bad block table pointer
    
52. * @bbt_td: [REPLACEABLE] bad block table descriptor for flash lookup
    
53. * @bbt_md: [REPLACEABLE] bad block table mirror descriptor
    
54. * @badblock_pattern: [REPLACEABLE] bad block scan pattern used for initial bad block scan
    
55. * @controller: [OPTIONAL] a pointer to a hardware controller structure which is shared among multiple independend devices
    
56. * @priv: [OPTIONAL] pointer to private chip date
    
57. */
    
58. 
    
59. struct nand_chip {
    
60. void __iomem *IO_ADDR_R;
    
61. void __iomem *IO_ADDR_W;
    
62. 
    
63. u_char (*read_byte)(struct mtd_info *mtd);
    
64. void (*write_byte)(struct mtd_info *mtd, u_char byte);
    
65. u16 (*read_word)(struct mtd_info *mtd);
    
66. void (*write_word)(struct mtd_info *mtd, u16 word);
    
67. 
    
68. void (*write_buf)(struct mtd_info *mtd, const u_char *buf, int len);
    
69. void (*read_buf)(struct mtd_info *mtd, u_char *buf, int len);
    
70. int (*verify_buf)(struct mtd_info *mtd, const u_char *buf, int len);
    
71. void (*select_chip)(struct mtd_info *mtd, int chip);
    
72. int (*block_bad)(struct mtd_info *mtd, loff_t ofs, int getchip);
    
73. int (*block_markbad)(struct mtd_info *mtd, loff_t ofs);
    
74. void (*hwcontrol)(struct mtd_info *mtd, int cmd);
    
75. int (*dev_ready)(struct mtd_info *mtd);
    
76. void (*cmdfunc)(struct mtd_info *mtd, unsigned command, int column, int page_addr);
    
77. int (*waitfunc)(struct mtd_info *mtd, struct nand_chip *this, int state);
    
78. int (*calculate_ecc)(struct mtd_info *mtd, const u_char *dat, u_char *ecc_code);
    
79. int (*correct_data)(struct mtd_info *mtd, u_char *dat, u_char *read_ecc, u_char *calc_ecc);
    
80. void (*enable_hwecc)(struct mtd_info *mtd, int mode);
    
81. void (*erase_cmd)(struct mtd_info *mtd, int page);
    
82. int (*scan_bbt)(struct mtd_info *mtd);
    
83. int eccmode;
    
84. int eccsize;
    
85. int eccbytes;
    
86. int eccsteps;
    
87. int chip_delay;
    
88. #if 0
    
89. spinlock_t chip_lock;
    
90. wait_queue_head_t wq;
    
91. nand_state_t state;
    
92. #endif
    
93. int page_shift;
    
94. int phys_erase_shift;
    
95. int bbt_erase_shift;
    
96. int chip_shift;
    
97. u_char *data_buf;
    
98. u_char *oob_buf;
    
99. int oobdirty;
    
100. u_char *data_poi;
     
101. unsigned int options;
     
102. int badblockpos;
     
103. int numchips;
     
104. unsigned long chipsize;
     
105. int pagemask;
     
106. int pagebuf;
     
107. struct nand_oobinfo *autooob;
     
108. uint8_t *bbt;
     
109. struct nand_bbt_descr *bbt_td;
     
110. struct nand_bbt_descr *bbt_md;
     
111. struct nand_bbt_descr *badblock_pattern;
     
112. struct nand_hw_control *controller;
     
113. void *priv;
     
114. };

参数3 base_address[i]，如下

static ulong base_address[CFG_MAX_NAND_DEVICE] = CFG_NAND_BASE_LIST;

CFG_NAND_BASE_LIST如下，

#ifndef CFG_NAND_BASE_LIST

#define CFG_NAND_BASE_LIST { CFG_NAND_BASE }

#endif

CFG_NAND_BASE是在include/configs/UB4020.h中配置为

#define CFG_NAND_BASE 0x11000200 （nand FIFO 数据寄存器）

(3)计算出总共nandflash多少容量，在紧随其后的printf语句中打印出来。

接着看同文件（driver/mtd/nand/nand.c）中nand_init_chip函数的分析

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1. static void nand_init_chip(struct mtd_info *mtd, struct nand_chip *nand, ulong base_addr)
   
2. {
   
3. mtd->priv = nand;
   
4. 
   
5. nand->IO_ADDR_R = nand->IO_ADDR_W = (void __iomem *)base_addr; //(1)
   
6. if (board_nand_init(nand) == 0) { //(2)
   
7. if (nand_scan(mtd, 1) == 0) { //(3)
   
8. if (!mtd->name) //这个名字在nand_scan中设置，如果在table中找到就有了。
   
9. mtd->name = (char *)default_nand_name;
   
10. } else
    
11. mtd->name = NULL;
    
12. } else {
    
13. mtd->name = NULL;
    
14. mtd->size = 0;
    
15. }
    
16. 
    
17. }

(1)从上面的nand_chip结构体中写道IO_ADDR_R，IO_ADDR_W是nand flash的读写地址， base_add这里设置为0x11000200，正好的nand FIFO的数据寄存器，读写flash的接口寄存器。

(2)此函数设置相关的nand 初始化，它和具体的体现结构有关系，不是共性的东西，在cpu/xxx/Nand_flash.c文件中。

(3) 此函数设置通用默认处理，获得flash id，并匹配等等。

这里我们分析的是sep4020 cpu的board_nand_init() 在cpu/sep4020/nand_flash.c

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1. int board_nand_init( struct nand_chip *chip )
   
2. {
   
3. memset((char *) chip, 0, sizeof(struct nand_chip));
   
4. 
   
5. INTC_IMR = 0XFFFFFFFF; //(REGW(INTC_BASE+0X008))IRQ中断屏蔽寄存器 置1为屏蔽 0为通过
   
6. INTC_IMR = 0X00000000;
   
7. 
   
8. EMI_NAND_CONF1 = 0x06402857; //(1)
   
9. EMI_NAND_CONF2 = 0x00d14353; //(2)
   
10. 
    
11. vaddr = malloc(2112); //(3)
    
12. oob64 = malloc(2112);
    
13. memset(vaddr,0,2112);
    
14. memset(oob64,0,2112);
    
15. 
    
16. int erasepage;
    
17. /*设置nand_chip结构中的各个函数指针*/
    
18. /* Set address of NAND IO lines */
    
19. chip->IO_ADDR_R = (void *) EMI_NAND_DATA_RAW; //设置nand flash读写寄存器地址，其实在调用函数中已经设置过了
    
20. chip->IO_ADDR_W = (void *) EMI_NAND_DATA_RAW;
    
21. /* Set address of hardware control function */
    
22. chip->hwcontrol = sep4020_hwcontrol;
    
23. /* 15 us command delay time */
    
24. chip->dev_ready = sep4020_nand_dev_ready;
    
25. chip->chip_delay = 15;
    
26. chip->write_buf = sep4020_nand_write_buf;
    
27. chip->read_buf = sep4020_nand_read_buf;
    
28. chip->write_byte = sep4020_nand_write_byte;
    
29. chip->read_byte = sep4020_nand_read_byte;
    
30. chip->eccmode = NAND_ECC_SOFT;
    
31. chip->select_chip = sep4020_nand_select_chip;
    
32. 
    
33. chip->cmdfunc = sep4020_nand_command;
    
34. chip->erase_cmd = sep4020_nand_cmd_erase;
    
35. /* Return happy */
    
36. return 0;
    
37. }

(1)NAND FLASH的配置器存器1 110-0--100--000000--101000--0101--0111 可查看芯片手册，其中一项设置成5级地址

(2)NAND FLASH的配置器存器2 1--1--0--100--010100--0011--01--01--00--11 可查看芯片手册，页大小配置为2K

(3)分配一个整页空间，后续的读写操作中会用到它来暂存一页数据。