SDBlockDevice.cpp

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2006-2012 ARM Limited
00003  *
00004  * Permission is hereby granted, free of charge, to any person obtaining a copy
00005  * of this software and associated documentation files (the "Software"), to deal
00006  * in the Software without restriction, including without limitation the rights
00007  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00008  * copies of the Software, and to permit persons to whom the Software is
00009  * furnished to do so, subject to the following conditions:
00010  *
00011  * The above copyright notice and this permission notice shall be included in
00012  * all copies or substantial portions of the Software.
00013  *
00014  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00015  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00016  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00017  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00018  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00019  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
00020  * SOFTWARE.
00021  */
00022 /* Introduction
00023  * ------------
00024  * SD and MMC cards support a number of interfaces, but common to them all
00025  * is one based on SPI. This is the one I'm implmenting because it means
00026  * it is much more portable even though not so performant, and we already
00027  * have the mbed SPI Interface!
00028  *
00029  * The main reference I'm using is Chapter 7, "SPI Mode" of:
00030  *  http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf
00031  *
00032  * SPI Startup
00033  * -----------
00034  * The SD card powers up in SD mode. The SPI interface mode is selected by
00035  * asserting CS low and sending the reset command (CMD0). The card will
00036  * respond with a (R1) response.
00037  *
00038  * CMD8 is optionally sent to determine the voltage range supported, and
00039  * indirectly determine whether it is a version 1.x SD/non-SD card or
00040  * version 2.x. I'll just ignore this for now.
00041  *
00042  * ACMD41 is repeatedly issued to initialise the card, until "in idle"
00043  * (bit 0) of the R1 response goes to '0', indicating it is initialised.
00044  *
00045  * You should also indicate whether the host supports High Capicity cards,
00046  * and check whether the card is high capacity - i'll also ignore this
00047  *
00048  * SPI Protocol
00049  * ------------
00050  * The SD SPI protocol is based on transactions made up of 8-bit words, with
00051  * the host starting every bus transaction by asserting the CS signal low. The
00052  * card always responds to commands, data blocks and errors.
00053  *
00054  * The protocol supports a CRC, but by default it is off (except for the
00055  * first reset CMD0, where the CRC can just be pre-calculated, and CMD8)
00056  * I'll leave the CRC off I think!
00057  *
00058  * Standard capacity cards have variable data block sizes, whereas High
00059  * Capacity cards fix the size of data block to 512 bytes. I'll therefore
00060  * just always use the Standard Capacity cards with a block size of 512 bytes.
00061  * This is set with CMD16.
00062  *
00063  * You can read and write single blocks (CMD17, CMD25) or multiple blocks
00064  * (CMD18, CMD25). For simplicity, I'll just use single block accesses. When
00065  * the card gets a read command, it responds with a response token, and then
00066  * a data token or an error.
00067  *
00068  * SPI Command Format
00069  * ------------------
00070  * Commands are 6-bytes long, containing the command, 32-bit argument, and CRC.
00071  *
00072  * +---------------+------------+------------+-----------+----------+--------------+
00073  * | 01 | cmd[5:0] | arg[31:24] | arg[23:16] | arg[15:8] | arg[7:0] | crc[6:0] | 1 |
00074  * +---------------+------------+------------+-----------+----------+--------------+
00075  *
00076  * As I'm not using CRC, I can fix that byte to what is needed for CMD0 (0x95)
00077  *
00078  * All Application Specific commands shall be preceded with APP_CMD (CMD55).
00079  *
00080  * SPI Response Format
00081  * -------------------
00082  * The main response format (R1) is a status byte (normally zero). Key flags:
00083  *  idle - 1 if the card is in an idle state/initialising
00084  *  cmd  - 1 if an illegal command code was detected
00085  *
00086  *    +-------------------------------------------------+
00087  * R1 | 0 | arg | addr | seq | crc | cmd | erase | idle |
00088  *    +-------------------------------------------------+
00089  *
00090  * R1b is the same, except it is followed by a busy signal (zeros) until
00091  * the first non-zero byte when it is ready again.
00092  *
00093  * Data Response Token
00094  * -------------------
00095  * Every data block written to the card is acknowledged by a byte
00096  * response token
00097  *
00098  * +----------------------+
00099  * | xxx | 0 | status | 1 |
00100  * +----------------------+
00101  *              010 - OK!
00102  *              101 - CRC Error
00103  *              110 - Write Error
00104  *
00105  * Single Block Read and Write
00106  * ---------------------------
00107  *
00108  * Block transfers have a byte header, followed by the data, followed
00109  * by a 16-bit CRC. In our case, the data will always be 512 bytes.
00110  *
00111  * +------+---------+---------+- -  - -+---------+-----------+----------+
00112  * | 0xFE | data[0] | data[1] |        | data[n] | crc[15:8] | crc[7:0] |
00113  * +------+---------+---------+- -  - -+---------+-----------+----------+
00114  */
00115 
00116 /* If the target has no SPI support then SDCard is not supported */
00117 #ifdef DEVICE_SPI
00118 
00119 #include "SDBlockDevice.h"
00120 #include "mbed_debug.h"
00121 
00122 #define SD_COMMAND_TIMEOUT 5000
00123 
00124 #define SD_DBG             0
00125 
00126 #define SD_BLOCK_DEVICE_ERROR_WOULD_BLOCK        -5001  /*!< operation would block */
00127 #define SD_BLOCK_DEVICE_ERROR_UNSUPPORTED        -5002  /*!< unsupported operation */
00128 #define SD_BLOCK_DEVICE_ERROR_PARAMETER          -5003  /*!< invalid parameter */
00129 #define SD_BLOCK_DEVICE_ERROR_NO_INIT            -5004  /*!< uninitialized */
00130 #define SD_BLOCK_DEVICE_ERROR_NO_DEVICE          -5005  /*!< device is missing or not connected */
00131 #define SD_BLOCK_DEVICE_ERROR_WRITE_PROTECTED    -5006  /*!< write protected */
00132 
00133 SDBlockDevice::SDBlockDevice(PinName mosi, PinName miso, PinName sclk, PinName cs)
00134     : _spi(mosi, miso, sclk), _cs(cs), _is_initialized(0)
00135 {
00136     _cs = 1;
00137 
00138     // Set default to 100kHz for initialisation and 1MHz for data transfer
00139     _init_sck = 100000;
00140     _transfer_sck = 1000000; //*90
00141 }
00142 
00143 SDBlockDevice::~SDBlockDevice()
00144 {
00145     if (_is_initialized) {
00146         deinit();
00147     }
00148 }
00149 
00150 #define R1_IDLE_STATE           (1 << 0)
00151 #define R1_ERASE_RESET          (1 << 1)
00152 #define R1_ILLEGAL_COMMAND      (1 << 2)
00153 #define R1_COM_CRC_ERROR        (1 << 3)
00154 #define R1_ERASE_SEQUENCE_ERROR (1 << 4)
00155 #define R1_ADDRESS_ERROR        (1 << 5)
00156 #define R1_PARAMETER_ERROR      (1 << 6)
00157 
00158 // Types
00159 //  - v1.x Standard Capacity
00160 //  - v2.x Standard Capacity
00161 //  - v2.x High Capacity
00162 //  - Not recognised as an SD Card
00163 #define SDCARD_FAIL 0
00164 #define SDCARD_V1   1
00165 #define SDCARD_V2   2
00166 #define SDCARD_V2HC 3
00167 
00168 int SDBlockDevice::_initialise_card()
00169 {
00170     _dbg = SD_DBG;
00171     // Set to SCK for initialisation, and clock card with cs = 1
00172     _spi.lock();
00173     _spi.frequency(_init_sck);
00174     _cs = 1;
00175     for (int i = 0; i < 16; i++) {
00176         _spi.write(0xFF);
00177     }
00178     _spi.unlock();
00179 
00180     // send CMD0, should return with all zeros except IDLE STATE set (bit 0)
00181     if (_cmd(0, 0) != R1_IDLE_STATE) {
00182         debug_if(_dbg, "No disk, or could not put SD card in to SPI idle state\n");
00183         return SD_BLOCK_DEVICE_ERROR_NO_DEVICE;
00184     }
00185 
00186     // send CMD8 to determine whther it is ver 2.x
00187     int r = _cmd8();
00188     if (r == R1_IDLE_STATE) {
00189         return _initialise_card_v2();
00190     } else if (r == (R1_IDLE_STATE | R1_ILLEGAL_COMMAND)) {
00191         return _initialise_card_v1();
00192     } else {
00193         debug_if(_dbg, "Not in idle state after sending CMD8 (not an SD card?)\n");
00194         return BD_ERROR_DEVICE_ERROR;
00195     }
00196 }
00197 
00198 int SDBlockDevice::_initialise_card_v1()
00199 {
00200     for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
00201         _cmd(55, 0);
00202         if (_cmd(41, 0) == 0) {
00203             _block_size = 512;
00204             debug_if(_dbg, "\n\rInit: SEDCARD_V1\n\r");
00205             return BD_ERROR_OK;
00206         }
00207     }
00208 
00209     debug_if(_dbg, "Timeout waiting for v1.x card\n");
00210     return BD_ERROR_DEVICE_ERROR;
00211 }
00212 
00213 int SDBlockDevice::_initialise_card_v2()
00214 {
00215     for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
00216         wait_ms(50);
00217         _cmd58();
00218         _cmd(55, 0);
00219         if (_cmd(41, 0x40000000) == 0) {
00220             _cmd58();
00221             debug_if(_dbg, "\n\rInit: SDCARD_V2\n\r");
00222             _block_size = 1;
00223             return BD_ERROR_OK;
00224         }
00225     }
00226 
00227     debug_if(_dbg, "Timeout waiting for v2.x card\n");
00228     return BD_ERROR_DEVICE_ERROR;
00229 }
00230 
00231 int SDBlockDevice::init()
00232 {
00233     _lock.lock();
00234     int err = _initialise_card();
00235     _is_initialized = (err == BD_ERROR_OK);
00236     if (!_is_initialized) {
00237         debug_if(_dbg, "Fail to initialize card\n");
00238         _lock.unlock();
00239         return err;
00240     }
00241     debug_if(_dbg, "init card = %d\n", _is_initialized);
00242     _sectors = _sd_sectors();
00243 
00244     // Set block length to 512 (CMD16)
00245     if (_cmd(16, 512) != 0) {
00246         debug_if(_dbg, "Set 512-byte block timed out\n");
00247         _lock.unlock();
00248         return BD_ERROR_DEVICE_ERROR;
00249     }
00250 
00251     // Set SCK for data transfer
00252     _spi.frequency(_transfer_sck);
00253     _lock.unlock();
00254     return BD_ERROR_OK;
00255 }
00256 
00257 int SDBlockDevice::deinit()
00258 {
00259     return 0;
00260 }
00261 
00262 int SDBlockDevice::program(const void *b, bd_addr_t addr, bd_size_t size)
00263 {
00264     if (!is_valid_program(addr, size)) {
00265         return SD_BLOCK_DEVICE_ERROR_PARAMETER;
00266     }
00267 
00268     _lock.lock();
00269     if (!_is_initialized) {
00270         _lock.unlock();
00271         return SD_BLOCK_DEVICE_ERROR_NO_INIT;
00272     }
00273 
00274     const uint8_t *buffer = static_cast<const uint8_t*>(b);
00275     while (size > 0) {
00276         bd_addr_t block = addr / 512;
00277         // set write address for single block (CMD24)
00278         if (_cmd(24, block * _block_size) != 0) {
00279             _lock.unlock();
00280             return BD_ERROR_DEVICE_ERROR;
00281         }
00282 
00283         // send the data block
00284         _write(buffer, 512);
00285         buffer += 512;
00286         addr += 512;
00287         size -= 512;
00288     }
00289     _lock.unlock();
00290     return 0;
00291 }
00292 
00293 int SDBlockDevice::read(void *b, bd_addr_t addr, bd_size_t size)
00294 {
00295     if (!is_valid_read(addr, size)) {
00296         return SD_BLOCK_DEVICE_ERROR_PARAMETER;
00297     }
00298 
00299     _lock.lock();
00300     if (!_is_initialized) {
00301         _lock.unlock();
00302         return SD_BLOCK_DEVICE_ERROR_PARAMETER;
00303     }
00304     
00305     uint8_t *buffer = static_cast<uint8_t *>(b);
00306     while (size > 0) {
00307         bd_addr_t block = addr / 512;
00308         // set read address for single block (CMD17)
00309         if (_cmd(17, block * _block_size) != 0) {
00310             _lock.unlock();
00311             return BD_ERROR_DEVICE_ERROR;
00312         }
00313         
00314         // receive the data
00315         _read(buffer, 512);
00316         buffer += 512;
00317         addr += 512;
00318         size -= 512;
00319     }
00320     _lock.unlock();
00321     return 0;
00322 }
00323 
00324 int SDBlockDevice::erase(bd_addr_t addr, bd_size_t size)
00325 {
00326     return 0;
00327 }
00328 
00329 bd_size_t SDBlockDevice::get_read_size() const
00330 {
00331     return 512;
00332 }
00333 
00334 bd_size_t SDBlockDevice::get_program_size() const
00335 {
00336     return 512;
00337 }
00338 
00339 bd_size_t SDBlockDevice::get_erase_size() const
00340 {
00341     return 512;
00342 }
00343 
00344 bd_size_t SDBlockDevice::size() const
00345 {
00346     bd_size_t sectors = 0;
00347     if(_is_initialized) {
00348         sectors = _sectors;
00349     }
00350     return 512*sectors;
00351 }
00352 
00353 void SDBlockDevice::debug(bool dbg)
00354 {
00355     _dbg = dbg;
00356 }
00357 
00358 const char *SDBlockDevice::get_type() const
00359 {
00360     return NULL;
00361 }
00362 
00363 
00364 // PRIVATE FUNCTIONS
00365 int SDBlockDevice::_cmd(int cmd, int arg) {
00366     _spi.lock();
00367     _cs = 0;
00368 
00369     // send a command
00370     _spi.write(0x40 | cmd);
00371     _spi.write(arg >> 24);
00372     _spi.write(arg >> 16);
00373     _spi.write(arg >> 8);
00374     _spi.write(arg >> 0);
00375     _spi.write(0x95);
00376 
00377     // wait for the repsonse (response[7] == 0)
00378     for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
00379         int response = _spi.write(0xFF);
00380         if (!(response & 0x80)) {
00381             _cs = 1;
00382             _spi.write(0xFF);
00383             _spi.unlock();
00384             return response;
00385         }
00386     }
00387     _cs = 1;
00388     _spi.write(0xFF);
00389     _spi.unlock();
00390     return -1; // timeout
00391 }
00392 int SDBlockDevice::_cmdx(int cmd, int arg) {
00393     _spi.lock();
00394     _cs = 0;
00395 
00396     // send a command
00397     _spi.write(0x40 | cmd);
00398     _spi.write(arg >> 24);
00399     _spi.write(arg >> 16);
00400     _spi.write(arg >> 8);
00401     _spi.write(arg >> 0);
00402     _spi.write(0x95);
00403 
00404     // wait for the repsonse (response[7] == 0)
00405     for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
00406         int response = _spi.write(0xFF);
00407         if (!(response & 0x80)) {
00408             _cs = 1;
00409             _spi.unlock();
00410             return response;
00411         }
00412     }
00413     _cs = 1;
00414     _spi.write(0xFF);
00415     _spi.unlock();
00416     return -1; // timeout
00417 }
00418 
00419 
00420 int SDBlockDevice::_cmd58() {
00421     _spi.lock();
00422     _cs = 0;
00423     int arg = 0;
00424 
00425     // send a command
00426     _spi.write(0x40 | 58);
00427     _spi.write(arg >> 24);
00428     _spi.write(arg >> 16);
00429     _spi.write(arg >> 8);
00430     _spi.write(arg >> 0);
00431     _spi.write(0x95);
00432 
00433     // wait for the repsonse (response[7] == 0)
00434     for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
00435         int response = _spi.write(0xFF);
00436         if (!(response & 0x80)) {
00437             int ocr = _spi.write(0xFF) << 24;
00438             ocr |= _spi.write(0xFF) << 16;
00439             ocr |= _spi.write(0xFF) << 8;
00440             ocr |= _spi.write(0xFF) << 0;
00441             _cs = 1;
00442             _spi.write(0xFF);
00443             _spi.unlock();
00444             return response;
00445         }
00446     }
00447     _cs = 1;
00448     _spi.write(0xFF);
00449     _spi.unlock();
00450     return -1; // timeout
00451 }
00452 
00453 int SDBlockDevice::_cmd8() {
00454     _spi.lock();
00455     _cs = 0;
00456 
00457     // send a command
00458     _spi.write(0x40 | 8); // CMD8
00459     _spi.write(0x00);     // reserved
00460     _spi.write(0x00);     // reserved
00461     _spi.write(0x01);     // 3.3v
00462     _spi.write(0xAA);     // check pattern
00463     _spi.write(0x87);     // crc
00464 
00465     // wait for the repsonse (response[7] == 0)
00466     for (int i = 0; i < SD_COMMAND_TIMEOUT * 1000; i++) {
00467         char response[5];
00468         response[0] = _spi.write(0xFF);
00469         if (!(response[0] & 0x80)) {
00470             for (int j = 1; j < 5; j++) {
00471                 response[i] = _spi.write(0xFF);
00472             }
00473             _cs = 1;
00474             _spi.write(0xFF);
00475             _spi.unlock();
00476             return response[0];
00477         }
00478     }
00479     _cs = 1;
00480     _spi.write(0xFF);
00481     _spi.unlock();
00482     return -1; // timeout
00483 }
00484 
00485 int SDBlockDevice::_read(uint8_t *buffer, uint32_t length) {
00486     _spi.lock();
00487     _cs = 0;
00488 
00489     // read until start byte (0xFF)
00490     while (_spi.write(0xFF) != 0xFE);
00491 
00492     // read data
00493     for (uint32_t i = 0; i < length; i++) {
00494         buffer[i] = _spi.write(0xFF);
00495     }
00496     _spi.write(0xFF); // checksum
00497     _spi.write(0xFF);
00498 
00499     _cs = 1;
00500     _spi.write(0xFF);
00501     _spi.unlock();
00502     return 0;
00503 }
00504 
00505 int SDBlockDevice::_write(const uint8_t*buffer, uint32_t length) {
00506     _spi.lock();
00507     _cs = 0;
00508 
00509     // indicate start of block
00510     _spi.write(0xFE);
00511 
00512     // write the data
00513     for (uint32_t i = 0; i < length; i++) {
00514         _spi.write(buffer[i]);
00515     }
00516 
00517     // write the checksum
00518     _spi.write(0xFF);
00519     _spi.write(0xFF);
00520 
00521     // check the response token
00522     if ((_spi.write(0xFF) & 0x1F) != 0x05) {
00523         _cs = 1;
00524         _spi.write(0xFF);
00525         _spi.unlock();
00526         return 1;
00527     }
00528 
00529     // wait for write to finish
00530     while (_spi.write(0xFF) == 0);
00531 
00532     _cs = 1;
00533     _spi.write(0xFF);
00534     _spi.unlock();
00535     return 0;
00536 }
00537 
00538 static uint32_t ext_bits(unsigned char *data, int msb, int lsb) {
00539     uint32_t bits = 0;
00540     uint32_t size = 1 + msb - lsb;
00541     for (uint32_t i = 0; i < size; i++) {
00542         uint32_t position = lsb + i;
00543         uint32_t byte = 15 - (position >> 3);
00544         uint32_t bit = position & 0x7;
00545         uint32_t value = (data[byte] >> bit) & 1;
00546         bits |= value << i;
00547     }
00548     return bits;
00549 }
00550 
00551 uint32_t SDBlockDevice::_sd_sectors() {
00552     uint32_t c_size, c_size_mult, read_bl_len;
00553     uint32_t block_len, mult, blocknr, capacity;
00554     uint32_t hc_c_size;
00555     uint32_t blocks;
00556 
00557     // CMD9, Response R2 (R1 byte + 16-byte block read)
00558     if (_cmdx(9, 0) != 0) {
00559         debug_if(_dbg, "Didn't get a response from the disk\n");
00560         return 0;
00561     }
00562 
00563     uint8_t csd[16];
00564     if (_read(csd, 16) != 0) {
00565         debug_if(_dbg, "Couldn't read csd response from disk\n");
00566         return 0;
00567     }
00568 
00569     // csd_structure : csd[127:126]
00570     // c_size        : csd[73:62]
00571     // c_size_mult   : csd[49:47]
00572     // read_bl_len   : csd[83:80] - the *maximum* read block length
00573 
00574     int csd_structure = ext_bits(csd, 127, 126);
00575 
00576     switch (csd_structure) {
00577         case 0:
00578             _block_size = 512;
00579             c_size = ext_bits(csd, 73, 62);
00580             c_size_mult = ext_bits(csd, 49, 47);
00581             read_bl_len = ext_bits(csd, 83, 80);
00582 
00583             block_len = 1 << read_bl_len;
00584             mult = 1 << (c_size_mult + 2);
00585             blocknr = (c_size + 1) * mult;
00586             capacity = blocknr * block_len;
00587             blocks = capacity / 512;
00588             debug_if(_dbg, "\n\rSDBlockDevice\n\rc_size: %d \n\rcapacity: %ld \n\rsectors: %lld\n\r", c_size, capacity, blocks);
00589             break;
00590 
00591         case 1:
00592             _block_size = 1;
00593             hc_c_size = ext_bits(csd, 63, 48);
00594             blocks = (hc_c_size+1)*1024;
00595             debug_if(_dbg, "\n\rSDHC Card \n\rhc_c_size: %d\n\rcapacity: %lld \n\rsectors: %lld\n\r", hc_c_size, blocks*512, blocks);
00596             break;
00597 
00598         default:
00599             debug_if(_dbg, "CSD struct unsupported\r\n");
00600             return 0;
00601     };
00602     return blocks;
00603 }
00604 
00605 #endif  /* DEVICE_SPI */
00606