u-boot-2016.03 支持yaffs2文件系統燒寫之添加nand write.yaffs2命令

　　咱們進入nand的命令文件cmd/nand.c，在do_nand函數裏，有nand read或write的代碼，而其中有對jffs2的支持，卻並無對yaffs2的支持。之前的老版本uboot是有對yaffs文件系統燒寫的支持的，因而咱們參考老版本的uboot代碼，在do_nand函數裏的nand write/read部分加上一段代碼，以下：

 1 #ifdef CONFIG_CMD_NAND_TRIMFFS
 2         } else if (!strcmp(s, ".trimffs")) {
 3             if (read) {
 4                 printf("Unknown nand command suffix ‘%s‘\n", s);
 5                  return 1;
 6             }
 7             ret = nand_write_skip_bad(nand, off, &rwsize, NULL,
 8                         maxsize, (u_char *)addr,
 9                         WITH_DROP_FFS | WITH_WR_VERIFY);
10 #endif
11 #ifdef CONFIG_CMD_NAND_YAFFS
12         } else if (!strcmp(s, ".yaffs2")) {
13             if (read) {
14                 printf("Unknown nand command suffix ‘%s‘.\n", s);
15                 return 1;
16             }
17             ret = nand_write_skip_bad(nand, off, &rwsize,NULL,//這裏參數和老版比要修改下
18                         maxsize,(u_char *)addr,
19                         WITH_YAFFS_OOB);
20 #endif

在nand_help_text[]裏添加nand write.yaffs的幫助信息：

    "nand read.raw - addr off|partition [count]\n"
    "nand write.raw - addr off|partition [count]\n"
    "    Use read.raw/write.raw to avoid ECC and access the flash as-is.\n"
#ifdef CONFIG_CMD_NAND_YAFFS
    "nand write.yaffs2 - addr off|partition size\n"
    "    write ‘size‘ bytes starting at offset ‘off‘ with yaffs format\n"
    "    from memory address ‘addr‘, skipping bad blocks.\n"
#endif  

nand_write_skip_bad函數內部也要修改：

 1    if (actual)
 2         *actual = 0; 
 3 #ifdef CONFIG_CMD_NAND_YAFFS                                                       
 4      if (flags & WITH_YAFFS_OOB) {                                                  
 5         if (flags & ~WITH_YAFFS_OOB)                                               
 6             return -EINVAL;                                                        
 7                                                                                    
 8         int pages;                                                                 
 9         pages = nand->erasesize / nand->writesize;                                 
10         blocksize = (pages * nand->oobsize) + nand->erasesize;                     
11         if (*length % (nand->writesize + nand->oobsize)) {                         
12             printf ("Attempt to write incomplete page"                             
13                 " in yaffs mode\n");                                               
14             return -EINVAL;                                                        
15         }                                                                          
16     } else                                                                         
17 #endif                                                                             
18     {                                                                              
19         blocksize = nand->erasesize;                                               
20     }    
21 
22     ...
23 
24 if (left_to_write < (blocksize - block_offset))                            
25         write_size = left_to_write;                                            
26      else                                                                       
27         write_size = blocksize - block_offset;                                 
28 #ifdef CONFIG_CMD_NAND_YAFFS                                                       
29     if (flags & WITH_YAFFS_OOB) {                                              
30         int page, pages;                                                       
31         size_t pagesize = nand->writesize;                                     
32         size_t pagesize_oob = pagesize + nand->oobsize;                        
33         struct mtd_oob_ops ops;                                                
34                                                                                
35         ops.len = pagesize;                                                    
36         ops.ooblen = nand->oobsize;                                            
37         ops.mode = MTD_OPS_RAW;       //這裏要改成RAW                                         
38         ops.ooboffs = 0;                                                       
39                                                                                
40         pages = write_size / pagesize_oob;                                     
41         for (page = 0; page < pages; page++) {                                 
42             WATCHDOG_RESET();                                                  
43                                                                                
44         ops.datbuf = p_buffer;                                             
45         ops.oobbuf = ops.datbuf + pagesize;                                
46                                                                            
47         rval = nand->_write_oob(nand, offset, &ops);                        
48         if (rval != 0) 
49              break;                                                         
50                                                                               
51              offset += pagesize;                                                
52              p_buffer += pagesize_oob;                                          
53             }                                                                      
54         }                                                                          
55         else                                                                       
56 #endif    
57      {          //這裏要加個左大括號                                                                
58              truncated_write_size = write_size;                                     
59 #ifdef CONFIG_CMD_NAND_TRIMFFS                                                     
60          if (flags & WITH_DROP_FFS)                                                 
61              truncated_write_size = drop_ffs(nand, p_buffer,                        
62                      &write_size);                                                  
63 #endif                                                                             
64                                                                                     
65          rval = nand_write(nand, offset, &truncated_write_size,                     
66                  p_buffer);                                                         
67                                                                                     
68          if ((flags & WITH_WR_VERIFY) && !rval)                                     
69              rval = nand_verify(nand, offset,                                       
70                  truncated_write_size, p_buffer);                                   
71                                                                                     
72          offset += write_size;                                                      
73          p_buffer += write_size;                                                    
74          } //這裏要加個右大括號                                                                         
75          if (rval != 0) {      

同時，在include/nand.h中添加WITH_YAFFS_OOB宏的定義，

#define WITH_YAFFS_OOB    (1 << 0)
#define WITH_DROP_FFS   (1 << 0)

 最後在配置文件裏添加CONFIG_CMD_NAND_YAFFS宏定義，編譯燒寫，成功燒寫yaffs2文件系統並掛載成功，此uboot已經支持yaffs2文件系統的燒寫。