SDFileSystemDMA.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 #include "SDFileSystemDMA.h"
00116 #include "mbed_debug.h"
00117 #include "spi_dma.h"
00118 
00119 #define __SPI_DMA__
00120 
00121 #define SD_COMMAND_TIMEOUT 5000
00122 
00123 #define SD_DBG             0
00124 
00125 SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name, uint32_t hz) :
00126     FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs), _is_initialized(0), _transfer_sck(hz) {
00127     _cs = 1;
00128 
00129     // Set default to 100kHz for initialisation and 1MHz for data transfer
00130     _init_sck = 100000;
00131     //_transfer_sck = 12000000;
00132     _spi_id = spi_get_id(mosi, miso, sclk, NC);
00133     spi_dma_init( _spi_id );
00134 }
00135 
00136 #define R1_IDLE_STATE           (1 << 0)
00137 #define R1_ERASE_RESET          (1 << 1)
00138 #define R1_ILLEGAL_COMMAND      (1 << 2)
00139 #define R1_COM_CRC_ERROR        (1 << 3)
00140 #define R1_ERASE_SEQUENCE_ERROR (1 << 4)
00141 #define R1_ADDRESS_ERROR        (1 << 5)
00142 #define R1_PARAMETER_ERROR      (1 << 6)
00143 
00144 // Types
00145 //  - v1.x Standard Capacity
00146 //  - v2.x Standard Capacity
00147 //  - v2.x High Capacity
00148 //  - Not recognised as an SD Card
00149 #define SDCARD_FAIL 0
00150 #define SDCARD_V1   1
00151 #define SDCARD_V2   2
00152 #define SDCARD_V2HC 3
00153 
00154 int SDFileSystem::initialise_card() {
00155     // Set to SCK for initialisation, and clock card with cs = 1
00156     _spi.frequency(_init_sck);
00157     _cs = 1;
00158     for (int i = 0; i < 16; i++) {
00159         _spi.write(0xFF);
00160     }
00161 
00162     // send CMD0, should return with all zeros except IDLE STATE set (bit 0)
00163     if (_cmd(0, 0) != R1_IDLE_STATE) {
00164         debug("No disk, or could not put SD card in to SPI idle state\n");
00165         return SDCARD_FAIL;
00166     }
00167 
00168     // send CMD8 to determine whther it is ver 2.x
00169     int r = _cmd8();
00170     if (r == R1_IDLE_STATE) {
00171         return initialise_card_v2();
00172     } else if (r == (R1_IDLE_STATE | R1_ILLEGAL_COMMAND)) {
00173         return initialise_card_v1();
00174     } else {
00175         debug("Not in idle state after sending CMD8 (not an SD card?)\n");
00176         return SDCARD_FAIL;
00177     }
00178 }
00179 
00180 int SDFileSystem::initialise_card_v1() {
00181     for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
00182         _cmd(55, 0);
00183         if (_cmd(41, 0) == 0) {
00184             cdv = 512;
00185             debug_if(SD_DBG, "\n\rInit: SEDCARD_V1\n\r");
00186             return SDCARD_V1;
00187         }
00188     }
00189 
00190     debug("Timeout waiting for v1.x card\n");
00191     return SDCARD_FAIL;
00192 }
00193 
00194 int SDFileSystem::initialise_card_v2() {
00195     for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
00196         wait_ms(50);
00197         _cmd58();
00198         _cmd(55, 0);
00199         if (_cmd(41, 0x40000000) == 0) {
00200             _cmd58();
00201             debug_if(SD_DBG, "\n\rInit: SDCARD_V2\n\r");
00202             cdv = 1;
00203             return SDCARD_V2;
00204         }
00205     }
00206 
00207     debug("Timeout waiting for v2.x card\n");
00208     return SDCARD_FAIL;
00209 }
00210 
00211 int SDFileSystem::disk_initialize() {
00212     _is_initialized = initialise_card();
00213     if (_is_initialized == 0) {
00214         debug("Fail to initialize card\n");
00215         return 1;
00216     }
00217     debug_if(SD_DBG, "init card = %d\n", _is_initialized);
00218     _sectors = _sd_sectors();
00219 
00220     // Set block length to 512 (CMD16)
00221     if (_cmd(16, 512) != 0) {
00222         debug("Set 512-byte block timed out\n");
00223         return 1;
00224     }
00225 
00226     // Set SCK for data transfer
00227     _spi.frequency(_transfer_sck);
00228     return 0;
00229 }
00230 
00231 int SDFileSystem::disk_write(const uint8_t* buffer, uint32_t block_number, uint32_t count) {
00232     if (!_is_initialized) {
00233         return -1;
00234     }
00235     
00236     for (uint32_t b = block_number; b < block_number + count; b++) {
00237         // set write address for single block (CMD24)
00238         if (_cmd(24, b * cdv) != 0) {
00239             return 1;
00240         }
00241         
00242         // send the data block
00243         _write(buffer, 512);
00244         buffer += 512;
00245     }
00246     
00247     return 0;
00248 }
00249 
00250 int SDFileSystem::disk_read(uint8_t* buffer, uint32_t block_number, uint32_t count) {
00251     if (!_is_initialized) {
00252         return -1;
00253     }
00254    
00255     if(count==1){
00256         //for (uint32_t b = block_number; b < block_number + count; b++) {
00257             // set read address for single block (CMD17)
00258             if (_cmd(17, block_number * cdv) != 0) {
00259                 return 1;
00260             }
00261 
00262             // receive the data
00263             _read(buffer, 512);
00264             buffer += 512;
00265         //}
00266     } else {
00267         int retry=4;
00268         while(retry--){
00269             if (_cmd(18, block_number * cdv ) == 0) {   /* READ_MULTIPLE_BLOCK */
00270                 do {
00271                     _read(buffer, 512);
00272                     buffer += 512;
00273                 } while (--count);
00274                 _cmd(12, 0);                /* STOP_TRANSMISSION */
00275                 break;
00276             } 
00277             else {
00278                 //error("\nCMD18: disk_read()");
00279             }
00280         }
00281         if(!retry) return 1;
00282     }
00283 
00284     return 0;
00285 }
00286 
00287 int SDFileSystem::disk_status() {
00288     // FATFileSystem::disk_status() returns 0 when initialized
00289     if (_is_initialized) {
00290         return 0;
00291     } else {
00292         return 1;
00293     }
00294 }
00295 
00296 int SDFileSystem::disk_sync() { return 0; }
00297 uint32_t SDFileSystem::disk_sectors() { return _sectors; }
00298 
00299 
00300 // PRIVATE FUNCTIONS
00301 int SDFileSystem::_cmd(int cmd, int arg) {
00302     _cs = 0;
00303 
00304     // send a command
00305     _spi.write(0x40 | cmd);
00306     _spi.write(arg >> 24);
00307     _spi.write(arg >> 16);
00308     _spi.write(arg >> 8);
00309     _spi.write(arg >> 0);
00310     _spi.write(0x95);
00311 
00312     // wait for the repsonse (response[7] == 0)
00313     for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
00314         int response = _spi.write(0xFF);
00315         if (!(response & 0x80)) {
00316             _cs = 1;
00317             _spi.write(0xFF);
00318             return response;
00319         }
00320     }
00321     _cs = 1;
00322     _spi.write(0xFF);
00323     return -1; // timeout
00324 }
00325 int SDFileSystem::_cmdx(int cmd, int arg) {
00326     _cs = 0;
00327 
00328     // send a command
00329     _spi.write(0x40 | cmd);
00330     _spi.write(arg >> 24);
00331     _spi.write(arg >> 16);
00332     _spi.write(arg >> 8);
00333     _spi.write(arg >> 0);
00334     _spi.write(0x95);
00335 
00336     // wait for the repsonse (response[7] == 0)
00337     for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
00338         int response = _spi.write(0xFF);
00339         if (!(response & 0x80)) {
00340             return response;
00341         }
00342     }
00343     _cs = 1;
00344     _spi.write(0xFF);
00345     return -1; // timeout
00346 }
00347 
00348 
00349 int SDFileSystem::_cmd58() {
00350     _cs = 0;
00351     int arg = 0;
00352 
00353     // send a command
00354     _spi.write(0x40 | 58);
00355     _spi.write(arg >> 24);
00356     _spi.write(arg >> 16);
00357     _spi.write(arg >> 8);
00358     _spi.write(arg >> 0);
00359     _spi.write(0x95);
00360 
00361     // wait for the repsonse (response[7] == 0)
00362     for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
00363         int response = _spi.write(0xFF);
00364         if (!(response & 0x80)) {
00365             int ocr = _spi.write(0xFF) << 24;
00366             ocr |= _spi.write(0xFF) << 16;
00367             ocr |= _spi.write(0xFF) << 8;
00368             ocr |= _spi.write(0xFF) << 0;
00369             _cs = 1;
00370             _spi.write(0xFF);
00371             return response;
00372         }
00373     }
00374     _cs = 1;
00375     _spi.write(0xFF);
00376     return -1; // timeout
00377 }
00378 
00379 int SDFileSystem::_cmd8() {
00380     _cs = 0;
00381 
00382     // send a command
00383     _spi.write(0x40 | 8); // CMD8
00384     _spi.write(0x00);     // reserved
00385     _spi.write(0x00);     // reserved
00386     _spi.write(0x01);     // 3.3v
00387     _spi.write(0xAA);     // check pattern
00388     _spi.write(0x87);     // crc
00389 
00390     // wait for the repsonse (response[7] == 0)
00391     for (int i = 0; i < SD_COMMAND_TIMEOUT * 1000; i++) {
00392         char response[5];
00393         response[0] = _spi.write(0xFF);
00394         if (!(response[0] & 0x80)) {
00395             for (int j = 1; j < 5; j++) {
00396                 response[i] = _spi.write(0xFF);
00397             }
00398             _cs = 1;
00399             _spi.write(0xFF);
00400             return response[0];
00401         }
00402     }
00403     _cs = 1;
00404     _spi.write(0xFF);
00405     return -1; // timeout
00406 }
00407 
00408 int SDFileSystem::_read(uint8_t *buffer, uint32_t length) {
00409     _cs = 0;
00410 
00411     // read until start byte (0xFF)
00412     while (_spi.write(0xFF) != 0xFE){/* just wait */}
00413 
00414     // read data
00415 #if defined( __SPI_DMA__)
00416     uint8_t dummyByte = 0xFF;
00417     spi_dma_read( _spi_id, &dummyByte, buffer, length );
00418 #else
00419     for (uint32_t i = 0; i < length; i++) {
00420         buffer[i] = _spi.write(0xFF);
00421     }
00422 #endif
00423     _spi.write(0xFF); // checksum
00424     _spi.write(0xFF);
00425 
00426     _cs = 1;
00427     _spi.write(0xFF);
00428     return 0;
00429 }
00430 
00431 int SDFileSystem::_write(const uint8_t *buffer, uint32_t length) {
00432     _cs = 0;
00433 
00434     // indicate start of block
00435     _spi.write(0xFE);
00436 
00437     // write the data
00438 #if defined( __SPI_DMA__)
00439     #if 1 
00440     uint8_t dummyByte ;
00441     spi_dma_write( _spi_id, (uint8_t *)buffer, &dummyByte, length );
00442     #else
00443     for (uint32_t i = 0; i < length; i++) {
00444         _spi.write(buffer[i]);
00445     }
00446     #endif
00447 #else
00448     for (uint32_t i = 0; i < length; i++) {
00449         _spi.write(buffer[i]);
00450     }
00451 #endif
00452     // write the checksum
00453     _spi.write(0xFF);
00454     _spi.write(0xFF);
00455 
00456     // check the response token
00457     if ((_spi.write(0xFF) & 0x1F) != 0x05) {
00458         _cs = 1;
00459         _spi.write(0xFF);
00460         return 1;
00461     }
00462 
00463     // wait for write to finish
00464     while (_spi.write(0xFF) == 0);
00465 
00466     _cs = 1;
00467     _spi.write(0xFF);
00468     return 0;
00469 }
00470 
00471 static uint32_t ext_bits(unsigned char *data, int msb, int lsb) {
00472     uint32_t bits = 0;
00473     uint32_t size = 1 + msb - lsb;
00474     for (uint32_t i = 0; i < size; i++) {
00475         uint32_t position = lsb + i;
00476         uint32_t byte = 15 - (position >> 3);
00477         uint32_t bit = position & 0x7;
00478         uint32_t value = (data[byte] >> bit) & 1;
00479         bits |= value << i;
00480     }
00481     return bits;
00482 }
00483 
00484 uint32_t SDFileSystem::_sd_sectors() {
00485     uint32_t c_size, c_size_mult, read_bl_len;
00486     uint32_t block_len, mult, blocknr, capacity;
00487     uint32_t hc_c_size;
00488     uint32_t blocks;
00489 
00490     // CMD9, Response R2 (R1 byte + 16-byte block read)
00491     if (_cmdx(9, 0) != 0) {
00492         debug("Didn't get a response from the disk\n");
00493         return 0;
00494     }
00495 
00496     uint8_t csd[16];
00497     if (_read(csd, 16) != 0) {
00498         debug("Couldn't read csd response from disk\n");
00499         return 0;
00500     }
00501 
00502     // csd_structure : csd[127:126]
00503     // c_size        : csd[73:62]
00504     // c_size_mult   : csd[49:47]
00505     // read_bl_len   : csd[83:80] - the *maximum* read block length
00506 
00507     int csd_structure = ext_bits(csd, 127, 126);
00508 
00509     switch (csd_structure) {
00510         case 0:
00511             cdv = 512;
00512             c_size = ext_bits(csd, 73, 62);
00513             c_size_mult = ext_bits(csd, 49, 47);
00514             read_bl_len = ext_bits(csd, 83, 80);
00515 
00516             block_len = 1 << read_bl_len;
00517             mult = 1 << (c_size_mult + 2);
00518             blocknr = (c_size + 1) * mult;
00519             capacity = blocknr * block_len;
00520             blocks = capacity / 512;
00521             debug_if(SD_DBG, "\n\rSDCard\n\rc_size: %d \n\rcapacity: %ld \n\rsectors: %lld\n\r", c_size, capacity, blocks);
00522             break;
00523 
00524         case 1:
00525             cdv = 1;
00526             hc_c_size = ext_bits(csd, 63, 48);
00527             blocks = (hc_c_size+1)*1024;
00528             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);
00529             break;
00530 
00531         default:
00532             debug("CSD struct unsupported\r\n");
00533             return 0;
00534     };
00535     return blocks;
00536 }