diskio.cpp

00001 /*-----------------------------------------------------------------------*/
00002 /* Low level disk I/O module skeleton for FatFs     (C)ChaN, 2007        */
00003 /*-----------------------------------------------------------------------*/
00004 /* This is a stub disk I/O module that acts as front end of the existing */
00005 /* disk I/O modules and attach it to FatFs module with common interface. */
00006 /*-----------------------------------------------------------------------*/
00007 
00008 #include "diskio.h"
00009 #include "mbed.h"
00010 #include "mbed_debug.h"
00011 
00012 
00013 //******************************************************************************************************************
00014 // MBED SPI/CS Select functions.... Modify for your layout.
00015 //**************************************************************************************
00016 
00017 SPI _spi(p5, p6, p7); // mosi, miso, sclk
00018 DigitalOut _cs(p8);
00019 
00020 //******************************************************************************************************************
00021 // Low Level Sector Access Function Prototypes('C' Castrated versions of Simon Ford's C++ MBED SDFileSystem class
00022 //******************************************************************************************************************
00023 int _cmd(int cmd, int arg);
00024 int _read(BYTE *buffer, int length);
00025 int _write(BYTE *buffer, int length);
00026 uint32_t ext_bits(BYTE *data, int msb, int lsb);
00027 int _sd_sectors();
00028 int _sectors;
00029 int _cmd(int cmd, int arg);
00030 int _cmdx(int cmd, int arg);
00031 int _cmd8();
00032 int _cmd58();
00033 int cdv;
00034 
00035 #define SD_COMMAND_TIMEOUT 5000
00036 
00037 #define R1_IDLE_STATE           (1 << 0)
00038 #define R1_ERASE_RESET          (1 << 1)
00039 #define R1_ILLEGAL_COMMAND      (1 << 2)
00040 #define R1_COM_CRC_ERROR        (1 << 3)
00041 #define R1_ERASE_SEQUENCE_ERROR (1 << 4)
00042 #define R1_ADDRESS_ERROR        (1 << 5)
00043 #define R1_PARAMETER_ERROR      (1 << 6)
00044 
00045 
00046 //******************************************************************************************************************
00047 // Sector Access functions for CHAN FatFs
00048 //******************************************************************************************************************
00049 
00050 DRESULT disk_ioctl (
00051     BYTE drv,        /* Physical drive nmuber (0..) */
00052     BYTE ctrl,        /* Control code */
00053     void *buff        /* Buffer to send/receive control data */
00054 )
00055 {
00056     DRESULT res;
00057 
00058     switch(ctrl) {
00059         case CTRL_SYNC:
00060             res = RES_OK;
00061             break;
00062 
00063         case GET_SECTOR_SIZE:
00064             res = RES_OK;
00065             *(WORD *)buff = 512;
00066             break;
00067 
00068         case GET_SECTOR_COUNT:
00069             res = RES_OK;
00070             *(DWORD *)buff = (WORD)_sd_sectors();
00071             break;
00072 
00073         case GET_BLOCK_SIZE:
00074             res = RES_OK;
00075             *(DWORD *)buff = 1;
00076             break;
00077 
00078         default:
00079             res = RES_OK;
00080             break;
00081     }
00082     return res;
00083 }
00084 
00085 DSTATUS card_initialize(BYTE Drive)
00086 {
00087     // Set to 100kHz for initialisation, and clock card with cs = 1
00088     _spi.frequency(100000);
00089     _cs = 1;
00090     for (int i = 0; i < 16; i++) {
00091         _spi.write(0xFF);
00092     }
00093 
00094     // send CMD0, should return with all zeros except IDLE STATE set (bit 0)
00095     if (_cmd(0, 0) != R1_IDLE_STATE) {
00096         debug("No disk, or could not put SD card in to SPI idle state\n");
00097         return STA_NOINIT;
00098     }
00099 
00100     // send CMD8 to determine whther it is ver 2.x
00101     int r = _cmd8();
00102     if (r == R1_IDLE_STATE) {
00103         for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
00104             wait_ms(50);
00105             _cmd58();
00106             _cmd(55, 0);
00107             if (_cmd(41, 0x40000000) == 0) {
00108                 _cmd58();
00109                 //debug_if(SD_DBG, "\n\rInit: SDCARD_V2\n\r");
00110                 cdv = 1;
00111                 return 0;
00112             }
00113         }
00114         debug("Timeout waiting for v2.x card\n");
00115         return STA_NOINIT;
00116 
00117     } else if (r == (R1_IDLE_STATE | R1_ILLEGAL_COMMAND)) {
00118         for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
00119             _cmd(55, 0);
00120             if (_cmd(41, 0) == 0) {
00121                 cdv = 512;
00122                 //debug_if(SD_DBG, "\n\rInit: SEDCARD_V1\n\r");
00123                 return 0;
00124             }
00125         }
00126         debug("Timeout waiting for v1.x card\n");
00127         return STA_NOINIT;
00128 
00129     } else {
00130         debug("Not in idle state after sending CMD8 (not an SD card?)\n");
00131         return STA_NOINIT;
00132     }
00133 }
00134 
00135 DSTATUS disk_initialize(BYTE Drive)
00136 {
00137     DSTATUS ret = card_initialize(Drive);
00138 
00139     _sectors = _sd_sectors();
00140 
00141     // Set block length to 512 (CMD16)
00142     if (_cmd(16, 512) != 0) {
00143         debug("Set 512-byte block timed out\n");
00144         return STA_NOINIT;
00145     }
00146 
00147     _spi.frequency(10000000); // Set to 10MHz for data transfer
00148     return ret;
00149 }
00150 
00151 DRESULT disk_write(BYTE Drive,const BYTE * Buffer, DWORD SectorNumber, BYTE SectorCount)
00152 {
00153     BYTE i;
00154 
00155     BYTE * MyBufOut = (BYTE *)Buffer;
00156 
00157     for(i=0; i<SectorCount; i++) {
00158         // set write address for single block (CMD24)
00159         if(_cmd(24, (SectorNumber + i) * 512 ) != 0) {
00160             return RES_ERROR;
00161         }
00162 
00163         // send the data block
00164         _write(MyBufOut, 512);
00165 
00166         MyBufOut+=512;
00167     }
00168     return RES_OK;
00169 }
00170 
00171 DRESULT disk_read(BYTE Drive, BYTE * Buffer,DWORD SectorNumber, BYTE SectorCount)
00172 {
00173     BYTE i;
00174     for(i=0; i<SectorCount; i++) {
00175         // set read address for single block (CMD17)
00176         if(_cmd(17, (SectorNumber+i) * 512) != 0) {
00177             return RES_ERROR;
00178         }
00179         // receive the data
00180         _read(Buffer, 512);
00181 
00182         Buffer+=512;
00183     }
00184     return RES_OK;
00185 }
00186 
00187 
00188 DWORD get_fattime(void)
00189 {
00190     time_t CurrentTimeStamp;
00191     tm *CurrentLocalTime;
00192     DWORD FATFSTimeCode;
00193 
00194     CurrentTimeStamp = time(NULL);
00195     CurrentLocalTime = localtime(&CurrentTimeStamp);
00196 
00197     //Map the tm struct time into the FatFs time code
00198     FATFSTimeCode =  ((CurrentLocalTime->tm_year-80)<<25) |
00199                      ((CurrentLocalTime->tm_mon+1)<<21)   |
00200                      ((CurrentLocalTime->tm_mday)<<16)    |
00201                      ((CurrentLocalTime->tm_hour)<<11)    |
00202                      ((CurrentLocalTime->tm_min)<<5)     |
00203                      ((CurrentLocalTime->tm_sec));
00204 
00205     return FATFSTimeCode;
00206 }
00207 
00208 DSTATUS disk_status(BYTE Drive)
00209 {
00210     return 0;
00211 }
00212 
00213 //**************************************************************************************
00214 // Low Level Sector Access Functions (Castrated versions of Simon Fords C++ MBED class
00215 //**************************************************************************************
00216 
00217 int _cmd(int cmd, int arg)
00218 {
00219     _cs = 0;
00220 
00221     // send a command
00222     _spi.write(0x40 | cmd);
00223     _spi.write(arg >> 24);
00224     _spi.write(arg >> 16);
00225     _spi.write(arg >> 8);
00226     _spi.write(arg >> 0);
00227     _spi.write(0x95);
00228 
00229     // wait for the repsonse (response[7] == 0)
00230     for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
00231         int response = _spi.write(0xFF);
00232         if (!(response & 0x80)) {
00233             _cs = 1;
00234             _spi.write(0xFF);
00235             return response;
00236         }
00237     }
00238     _cs = 1;
00239     _spi.write(0xFF);
00240     return -1; // timeout
00241 }
00242 int _cmdx(int cmd, int arg)
00243 {
00244     _cs = 0;
00245 
00246     // send a command
00247     _spi.write(0x40 | cmd);
00248     _spi.write(arg >> 24);
00249     _spi.write(arg >> 16);
00250     _spi.write(arg >> 8);
00251     _spi.write(arg >> 0);
00252     _spi.write(0x95);
00253 
00254     // wait for the repsonse (response[7] == 0)
00255     for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
00256         int response = _spi.write(0xFF);
00257         if (!(response & 0x80)) {
00258             return response;
00259         }
00260     }
00261     _cs = 1;
00262     _spi.write(0xFF);
00263     return -1; // timeout
00264 }
00265 
00266 
00267 int _cmd58()
00268 {
00269     _cs = 0;
00270     int arg = 0;
00271 
00272     // send a command
00273     _spi.write(0x40 | 58);
00274     _spi.write(arg >> 24);
00275     _spi.write(arg >> 16);
00276     _spi.write(arg >> 8);
00277     _spi.write(arg >> 0);
00278     _spi.write(0x95);
00279 
00280     // wait for the repsonse (response[7] == 0)
00281     for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
00282         int response = _spi.write(0xFF);
00283         if (!(response & 0x80)) {
00284             int ocr = _spi.write(0xFF) << 24;
00285             ocr |= _spi.write(0xFF) << 16;
00286             ocr |= _spi.write(0xFF) << 8;
00287             ocr |= _spi.write(0xFF) << 0;
00288             _cs = 1;
00289             _spi.write(0xFF);
00290             return response;
00291         }
00292     }
00293     _cs = 1;
00294     _spi.write(0xFF);
00295     return -1; // timeout
00296 }
00297 
00298 int _cmd8()
00299 {
00300     _cs = 0;
00301 
00302     // send a command
00303     _spi.write(0x40 | 8); // CMD8
00304     _spi.write(0x00);     // reserved
00305     _spi.write(0x00);     // reserved
00306     _spi.write(0x01);     // 3.3v
00307     _spi.write(0xAA);     // check pattern
00308     _spi.write(0x87);     // crc
00309 
00310     // wait for the repsonse (response[7] == 0)
00311     for (int i = 0; i < SD_COMMAND_TIMEOUT * 1000; i++) {
00312         char response[5];
00313         response[0] = _spi.write(0xFF);
00314         if (!(response[0] & 0x80)) {
00315             for (int j = 1; j < 5; j++) {
00316                 response[i] = _spi.write(0xFF);
00317             }
00318             _cs = 1;
00319             _spi.write(0xFF);
00320             return response[0];
00321         }
00322     }
00323     _cs = 1;
00324     _spi.write(0xFF);
00325     return -1; // timeout
00326 }
00327 int _read(BYTE *buffer, int length)
00328 {
00329     _cs = 0;
00330 
00331     // read until start byte (0xFF)
00332     while (_spi.write(0xFF) != 0xFE);
00333 
00334     // read data
00335     for (int i = 0; i < length; i++) {
00336         buffer[i] = _spi.write(0xFF);
00337     }
00338     _spi.write(0xFF); // checksum
00339     _spi.write(0xFF);
00340 
00341     _cs = 1;
00342     _spi.write(0xFF);
00343     return 0;
00344 }
00345 
00346 
00347 int _write(BYTE *buffer, int length)
00348 {
00349     _cs = 0;
00350 
00351     // indicate start of block
00352     _spi.write(0xFE);
00353 
00354     // write the data
00355     for (int i = 0; i < length; i++) {
00356         _spi.write(buffer[i]);
00357     }
00358 
00359     // write the checksum
00360     _spi.write(0xFF);
00361     _spi.write(0xFF);
00362 
00363     // check the response token
00364     if ((_spi.write(0xFF) & 0x1F) != 0x05) {
00365         _cs = 1;
00366         _spi.write(0xFF);
00367         return 1;
00368     }
00369 
00370     // wait for write to finish
00371     while (_spi.write(0xFF) == 0);
00372 
00373     _cs = 1;
00374     _spi.write(0xFF);
00375     return 0;
00376 }
00377 
00378 static uint32_t ext_bits(unsigned char *data, int msb, int lsb)
00379 {
00380     uint32_t bits = 0;
00381     uint32_t size = 1 + msb - lsb;
00382     for (int i = 0; i < size; i++) {
00383         uint32_t position = lsb + i;
00384         uint32_t byte = 15 - (position >> 3);
00385         uint32_t bit = position & 0x7;
00386         uint32_t value = (data[byte] >> bit) & 1;
00387         bits |= value << i;
00388     }
00389     return bits;
00390 }
00391 
00392 int _sd_sectors()
00393 {
00394     uint32_t c_size, c_size_mult, read_bl_len;
00395     uint32_t block_len, mult, blocknr, capacity;
00396     uint32_t hc_c_size;
00397     uint64_t blocks;
00398 
00399     // CMD9, Response R2 (R1 byte + 16-byte block read)
00400     if (_cmdx(9, 0) != 0) {
00401         debug("Didn't get a response from the disk\n");
00402         return 0;
00403     }
00404 
00405     uint8_t csd[16];
00406     if (_read(csd, 16) != 0) {
00407         debug("Couldn't read csd response from disk\n");
00408         return 0;
00409     }
00410 
00411     // csd_structure : csd[127:126]
00412     // c_size        : csd[73:62]
00413     // c_size_mult   : csd[49:47]
00414     // read_bl_len   : csd[83:80] - the *maximum* read block length
00415 
00416     int csd_structure = ext_bits(csd, 127, 126);
00417 
00418     switch (csd_structure) {
00419         case 0:
00420             cdv = 512;
00421             c_size = ext_bits(csd, 73, 62);
00422             c_size_mult = ext_bits(csd, 49, 47);
00423             read_bl_len = ext_bits(csd, 83, 80);
00424 
00425             block_len = 1 << read_bl_len;
00426             mult = 1 << (c_size_mult + 2);
00427             blocknr = (c_size + 1) * mult;
00428             capacity = blocknr * block_len;
00429             blocks = capacity / 512;
00430             //debug_if(SD_DBG, "\n\rSDCard\n\rc_size: %d \n\rcapacity: %ld \n\rsectors: %lld\n\r", c_size, capacity, blocks);
00431             break;
00432 
00433         case 1:
00434             cdv = 1;
00435             hc_c_size = ext_bits(csd, 63, 48);
00436             blocks = (hc_c_size+1)*1024;
00437             //debug_if(SD_DBG, "\n\rSDHC Card \n\rhc_c_size: %d\n\rcapacity: %lld \n\rsectors: %lld\n\r", hc_c_size, blocks*512, blocks);
00438             break;
00439 
00440         default:
00441             debug("CSD struct unsupported\r\n");
00442             return 0;
00443     };
00444     return blocks;
00445 }