betty/pffs.c

   1 /*
   2  * pffs.c - pseudo flash filesystem
   3  *
   4  * author: hackbard@hackdaworld.org
   5  *
   6  */
   7
   8 #include "pffs.h"
   9
  10 /*
  11  * functions
  12  */
  13
  14 u32 pffs_get_ptr(t_pffs *pffs,u8 sector) {
  15
  16         u16 data[3];
  17         u32 iaddr;
  18         u32 daddr;
  19         u8 fnlen;
  20         u8 found;
  21
  22         iaddr=0;
  23         daddr=0;
  24         found=0;
  25
  26         while(1) {
  27                 pffs->fr(pffs->base_addr+pffs->sec_addr[sector]+iaddr,data,6);
  28                 if(!((data[0]&0xff00)==PFFS_INDEX_MAGIC))
  29                         break;
  30                 found=1;
  31                 fnlen=(data[0]&0x00f0)>>4;
  32                 iaddr+=(6+fnlen+fnlen);
  33                 daddr=((data[0]&0x000f)<<16)|data[1];
  34         }
  35
  36         pffs->data_ptr=daddr;
  37
  38         if(found) {
  39                 pffs->index_ptr=pffs->sec_addr[sector]+iaddr;
  40                 return 0;
  41         }
  42         else
  43                 return -1;
  44 }
  45
  46 int pffs_sec_empty(t_pffs *pffs,u8 sec) {
  47
  48         u32 addr;
  49         u16 data;
  50
  51         addr=pffs->base_addr|pffs->sec_addr[sec];
  52
  53         while(addr<(pffs->base_addr|pffs->sec_addr[sec+1])) {
  54                 data=*((u16 *)(addr));
  55                 if(data!=0xffff)
  56                         return 0;
  57                 addr+=2;
  58         }
  59
  60         return 1;
  61 }
  62
  63 #define pffs_sec_erase(pffs,sec) pffs->fe(pffs->base_addr|pffs->sec_addr[sec])
  64
  65 int pffs_reorientate(t_pffs *pffs) {
  66
  67         u8 sec,sec0,sec1;
  68
  69         /* check index sectors */
  70         sec0=pffs->sec_num_index[0];
  71         sec1=pffs->sec_num_index[1];
  72         if(!(pffs_get_ptr(pffs,sec0)&pffs_get_ptr(pffs,sec1)))
  73                 return 0;
  74
  75         /* initial run => no data + no index assumed => check whether erased! */
  76         // erase index sectors
  77         if(!pffs_sec_empty(pffs,sec0))
  78                 pffs_sec_erase(pffs,sec0);
  79         if(!pffs_sec_empty(pffs,sec1))
  80                 pffs_sec_erase(pffs,sec1);
  81         // erase data sectors
  82         sec0=pffs->sec_num_data[0];
  83         sec1=pffs->sec_num_data[1];
  84         for(sec=sec0;sec<=sec1;sec++)
  85                 if(!pffs_sec_empty(pffs,sec))
  86                         pffs_sec_erase(pffs,sec);
  87
  88         return 0;
  89 }
  90
  91 int pffs_flash_register(t_pffs *pffs,u32 base_addr,u8 sec_num,u32 *sec_addr,
  92                         u8 sec_num_data_min,u8 sec_num_data_max,
  93                         u8 sec_num_index0,u8 sec_num_index1,
  94                         int (*fw)(u32 addr,u16 *buf,int len),
  95                         int (*fr)(u32 addr,u16 *buf,int len),
  96                         int (*fe)(u32 addr)) {
  97
  98         /* assign physical flash specs */
  99         pffs->base_addr=base_addr;
 100         pffs->sec_num=sec_num;
 101         pffs->sec_addr=sec_addr;
 102
 103         /* specified index and data sectors */
 104         pffs->sec_num_data[0]=sec_num_data_min;
 105         pffs->sec_num_data[1]=sec_num_data_max;
 106         pffs->sec_num_index[0]=sec_num_index0;
 107         pffs->sec_num_index[1]=sec_num_index1;
 108
 109         /* flash acccess function pointers */
 110         pffs->fw=fw;
 111         pffs->fr=fr;
 112         pffs->fe=fe;
 113
 114         /* orientate */
 115         pffs_reorientate(pffs);
 116
 117         pffs->state|=PFFS_REGISTERED;
 118
 119         return 0;
 120 }
 121
 122 int pffs_init(t_pffs *pffs) {
 123
 124         if(!(pffs->state&PFFS_REGISTERED))
 125                 return -1;
 126
 127         return 0;
 128 }
 129