Diff: ChaNFSSD/SDFileSystem.cpp

Revision:

16:c753717bfd4d

Parent:

14:757226626acb

--- a/ChaNFSSD/SDFileSystem.cpp	Tue Dec 06 14:07:51 2011 +0000
+++ b/ChaNFSSD/SDFileSystem.cpp	Sun Dec 11 13:35:44 2011 +0000
@@ -24,20 +24,20 @@
  * ------------
  * SD and MMC cards support a number of interfaces, but common to them all
  * is one based on SPI. This is the one I'm implmenting because it means
- * it is much more portable even though not so performant, and we already
+ * it is much more portable even though not so performant, and we already 
  * have the mbed SPI Interface!
  *
- * The main reference I'm using is Chapter 7, "SPI Mode" of:
+ * The main reference I'm using is Chapter 7, "SPI Mode" of: 
  *  http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf
  *
  * SPI Startup
  * -----------
  * The SD card powers up in SD mode. The SPI interface mode is selected by
- * asserting CS low and sending the reset command (CMD0). The card will
+ * asserting CS low and sending the reset command (CMD0). The card will 
  * respond with a (R1) response.
  *
- * CMD8 is optionally sent to determine the voltage range supported, and
- * indirectly determine whether it is a version 1.x SD/non-SD card or
+ * CMD8 is optionally sent to determine the voltage range supported, and 
+ * indirectly determine whether it is a version 1.x SD/non-SD card or 
  * version 2.x. I'll just ignore this for now.
  *
  * ACMD41 is repeatedly issued to initialise the card, until "in idle"
@@ -51,21 +51,21 @@
  * The SD SPI protocol is based on transactions made up of 8-bit words, with
  * the host starting every bus transaction by asserting the CS signal low. The
  * card always responds to commands, data blocks and errors.
- *
- * The protocol supports a CRC, but by default it is off (except for the
+ * 
+ * The protocol supports a CRC, but by default it is off (except for the 
  * first reset CMD0, where the CRC can just be pre-calculated, and CMD8)
- * I'll leave the CRC off I think!
- *
- * Standard capacity cards have variable data block sizes, whereas High
+ * I'll leave the CRC off I think! 
+ * 
+ * Standard capacity cards have variable data block sizes, whereas High 
  * Capacity cards fix the size of data block to 512 bytes. I'll therefore
  * just always use the Standard Capacity cards with a block size of 512 bytes.
  * This is set with CMD16.
  *
- * You can read and write single blocks (CMD17, CMD25) or multiple blocks
+ * You can read and write single blocks (CMD17, CMD25) or multiple blocks 
  * (CMD18, CMD25). For simplicity, I'll just use single block accesses. When
- * the card gets a read command, it responds with a response token, and then
+ * the card gets a read command, it responds with a response token, and then 
  * a data token or an error.
- *
+ * 
  * SPI Command Format
  * ------------------
  * Commands are 6-bytes long, containing the command, 32-bit argument, and CRC.
@@ -81,7 +81,7 @@
  * SPI Response Format
  * -------------------
  * The main response format (R1) is a status byte (normally zero). Key flags:
- *  idle - 1 if the card is in an idle state/initialising
+ *  idle - 1 if the card is in an idle state/initialising 
  *  cmd  - 1 if an illegal command code was detected
  *
  *    +-------------------------------------------------+
@@ -93,7 +93,7 @@
  *
  * Data Response Token
  * -------------------
- * Every data block written to the card is acknowledged by a byte
+ * Every data block written to the card is acknowledged by a byte 
  * response token
  *
  * +----------------------+
@@ -108,20 +108,19 @@
  *
  * Block transfers have a byte header, followed by the data, followed
  * by a 16-bit CRC. In our case, the data will always be 512 bytes.
- *
+ *  
  * +------+---------+---------+- -  - -+---------+-----------+----------+
- * | 0xFE | data[0] | data[1] |        | data[n] | crc[15:8] | crc[7:0] |
+ * | 0xFE | data[0] | data[1] |        | data[n] | crc[15:8] | crc[7:0] | 
  * +------+---------+---------+- -  - -+---------+-----------+----------+
  */
-
+ 
 #include "SDFileSystem.h"
 
 #define SD_COMMAND_TIMEOUT 5000
 
 SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name) :
-        FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs) {
-    _status = 0;
-    _cs = 1;
+  FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs) {
+      _cs = 1;
 }
 
 #define R1_IDLE_STATE           (1 << 0)
@@ -145,23 +144,23 @@
 
 int SDFileSystem::initialise_card() {
     // Set to 100kHz for initialisation, and clock card with cs = 1
-    _spi.frequency(100000);
+    _spi.frequency(100000); 
     _cs = 1;
-    for (int i=0; i<16; i++) {
+    for(int i=0; i<16; i++) {   
         _spi.write(0xFF);
     }
 
     // send CMD0, should return with all zeros except IDLE STATE set (bit 0)
-    if (_cmd(0, 0) != R1_IDLE_STATE) {
+    if(_cmd(0, 0) != R1_IDLE_STATE) { 
         fprintf(stderr, "No disk, or could not put SD card in to SPI idle state\n");
         return SDCARD_FAIL;
     }
 
     // send CMD8 to determine whther it is ver 2.x
     int r = _cmd8();
-    if (r == R1_IDLE_STATE) {
+    if(r == R1_IDLE_STATE) {
         return initialise_card_v2();
-    } else if (r == (R1_IDLE_STATE | R1_ILLEGAL_COMMAND)) {
+    } else if(r == (R1_IDLE_STATE | R1_ILLEGAL_COMMAND)) {
         return initialise_card_v1();
     } else {
         fprintf(stderr, "Not in idle state after sending CMD8 (not an SD card?)\n");
@@ -170,9 +169,9 @@
 }
 
 int SDFileSystem::initialise_card_v1() {
-    for (int i=0; i<SD_COMMAND_TIMEOUT; i++) {
-        _cmd(55, 0);
-        if (_cmd(41, 0) == 0) {
+    for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
+        _cmd(55, 0); 
+        if(_cmd(41, 0) == 0) { 
             return SDCARD_V1;
         }
     }
@@ -182,10 +181,10 @@
 }
 
 int SDFileSystem::initialise_card_v2() {
-
-    for (int i=0; i<SD_COMMAND_TIMEOUT; i++) {
-        _cmd(55, 0);
-        if (_cmd(41, 0) == 0) {
+    
+    for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
+        _cmd(55, 0); 
+        if(_cmd(41, 0) == 0) { 
             _cmd58();
             return SDCARD_V2;
         }
@@ -204,51 +203,45 @@
     _sectors = _sd_sectors();
 
     // Set block length to 512 (CMD16)
-    if (_cmd(16, 512) != 0) {
+    if(_cmd(16, 512) != 0) {
         fprintf(stderr, "Set 512-byte block timed out\n");
         return 1;
     }
-
+        
     _spi.frequency(5000000); // Set to 5MHz for data transfer
-    return _status;
+    return 0;
 }
 
 int SDFileSystem::disk_write(const char *buffer, int block_number) {
     // set write address for single block (CMD24)
-    if (_cmd(24, block_number * 512) != 0) {
+    if(_cmd(24, block_number * 512) != 0) {
         return 1;
     }
 
     // send the data block
-    _write(buffer, 512);
-    return 0;
+    _write(buffer, 512);    
+    return 0;    
 }
 
-int SDFileSystem::disk_read(char *buffer, int block_number) {
+int SDFileSystem::disk_read(char *buffer, int block_number) {        
     // set read address for single block (CMD17)
-    if (_cmd(17, block_number * 512) != 0) {
+    if(_cmd(17, block_number * 512) != 0) {
         return 1;
     }
-
+    
     // receive the data
     _read(buffer, 512);
     return 0;
 }
 
-int SDFileSystem::disk_status() {
-    return _status;
-}
-int SDFileSystem::disk_sync() {
-    return 0;
-}
-int SDFileSystem::disk_sectors() {
-    return _sectors;
-}
+int SDFileSystem::disk_status() { return 0; }
+int SDFileSystem::disk_sync() { return 0; }
+int SDFileSystem::disk_sectors() { return _sectors; }
 
 // PRIVATE FUNCTIONS
 
 int SDFileSystem::_cmd(int cmd, int arg) {
-    _cs = 0;
+    _cs = 0; 
 
     // send a command
     _spi.write(0x40 | cmd);
@@ -259,9 +252,9 @@
     _spi.write(0x95);
 
     // wait for the repsonse (response[7] == 0)
-    for (int i=0; i<SD_COMMAND_TIMEOUT; i++) {
+    for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
         int response = _spi.write(0xFF);
-        if (!(response & 0x80)) {
+        if(!(response & 0x80)) {
             _cs = 1;
             _spi.write(0xFF);
             return response;
@@ -272,7 +265,7 @@
     return -1; // timeout
 }
 int SDFileSystem::_cmdx(int cmd, int arg) {
-    _cs = 0;
+    _cs = 0; 
 
     // send a command
     _spi.write(0x40 | cmd);
@@ -283,9 +276,9 @@
     _spi.write(0x95);
 
     // wait for the repsonse (response[7] == 0)
-    for (int i=0; i<SD_COMMAND_TIMEOUT; i++) {
+    for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
         int response = _spi.write(0xFF);
-        if (!(response & 0x80)) {
+        if(!(response & 0x80)) {
             return response;
         }
     }
@@ -296,9 +289,9 @@
 
 
 int SDFileSystem::_cmd58() {
-    _cs = 0;
+    _cs = 0; 
     int arg = 0;
-
+    
     // send a command
     _spi.write(0x40 | 58);
     _spi.write(arg >> 24);
@@ -308,9 +301,9 @@
     _spi.write(0x95);
 
     // wait for the repsonse (response[7] == 0)
-    for (int i=0; i<SD_COMMAND_TIMEOUT; i++) {
+    for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
         int response = _spi.write(0xFF);
-        if (!(response & 0x80)) {
+        if(!(response & 0x80)) {
             int ocr = _spi.write(0xFF) << 24;
             ocr |= _spi.write(0xFF) << 16;
             ocr |= _spi.write(0xFF) << 8;
@@ -327,8 +320,8 @@
 }
 
 int SDFileSystem::_cmd8() {
-    _cs = 0;
-
+    _cs = 0; 
+    
     // send a command
     _spi.write(0x40 | 8); // CMD8
     _spi.write(0x00);     // reserved
@@ -338,16 +331,16 @@
     _spi.write(0x87);     // crc
 
     // wait for the repsonse (response[7] == 0)
-    for (int i=0; i<SD_COMMAND_TIMEOUT * 1000; i++) {
+    for(int i=0; i<SD_COMMAND_TIMEOUT * 1000; i++) {
         char response[5];
         response[0] = _spi.write(0xFF);
-        if (!(response[0] & 0x80)) {
-            for (int j=1; j<5; j++) {
-                response[i] = _spi.write(0xFF);
-            }
-            _cs = 1;
-            _spi.write(0xFF);
-            return response[0];
+        if(!(response[0] & 0x80)) {
+                for(int j=1; j<5; j++) {
+                    response[i] = _spi.write(0xFF);
+                }
+                _cs = 1;
+                _spi.write(0xFF);
+                return response[0];
         }
     }
     _cs = 1;
@@ -359,54 +352,54 @@
     _cs = 0;
 
     // read until start byte (0xFF)
-    while (_spi.write(0xFF) != 0xFE);
+    while(_spi.write(0xFF) != 0xFE);
 
     // read data
-    for (int i=0; i<length; i++) {
+    for(int i=0; i<length; i++) {
         buffer[i] = _spi.write(0xFF);
     }
     _spi.write(0xFF); // checksum
     _spi.write(0xFF);
 
-    _cs = 1;
+    _cs = 1;    
     _spi.write(0xFF);
     return 0;
 }
 
 int SDFileSystem::_write(const char *buffer, int length) {
     _cs = 0;
-
+    
     // indicate start of block
     _spi.write(0xFE);
-
+    
     // write the data
-    for (int i=0; i<length; i++) {
+    for(int i=0; i<length; i++) {
         _spi.write(buffer[i]);
     }
-
+    
     // write the checksum
-    _spi.write(0xFF);
+    _spi.write(0xFF); 
     _spi.write(0xFF);
 
     // check the repsonse token
-    if ((_spi.write(0xFF) & 0x1F) != 0x05) {
+    if((_spi.write(0xFF) & 0x1F) != 0x05) {
         _cs = 1;
-        _spi.write(0xFF);
+        _spi.write(0xFF);        
         return 1;
     }
 
     // wait for write to finish
-    while (_spi.write(0xFF) == 0);
+    while(_spi.write(0xFF) == 0);
 
-    _cs = 1;
+    _cs = 1; 
     _spi.write(0xFF);
     return 0;
 }
 
 static int ext_bits(char *data, int msb, int lsb) {
     int bits = 0;
-    int size = 1 + msb - lsb;
-    for (int i=0; i<size; i++) {
+    int size = 1 + msb - lsb; 
+    for(int i=0; i<size; i++) {
         int position = lsb + i;
         int byte = 15 - (position >> 3);
         int bit = position & 0x7;
@@ -419,13 +412,13 @@
 int SDFileSystem::_sd_sectors() {
 
     // CMD9, Response R2 (R1 byte + 16-byte block read)
-    if (_cmdx(9, 0) != 0) {
+    if(_cmdx(9, 0) != 0) {
         fprintf(stderr, "Didn't get a response from the disk\n");
         return 0;
     }
-
-    char csd[16];
-    if (_read(csd, 16) != 0) {
+    
+    char csd[16];    
+    if(_read(csd, 16) != 0) {
         fprintf(stderr, "Couldn't read csd response from disk\n");
         return 0;
     }
@@ -441,8 +434,8 @@
     int read_bl_len = ext_bits(csd, 83, 80);
 
 //    printf("CSD_STRUCT = %d\n", csd_structure);
-
-    if (csd_structure != 0) {
+    
+    if(csd_structure != 0) {
         fprintf(stderr, "This disk tastes funny! I only know about type 0 CSD structures\n");
         return 0;
     }
@@ -451,7 +444,7 @@
     // where
     //  BLOCKNR = (C_SIZE+1) * MULT
     //  MULT = 2^(C_SIZE_MULT+2) (C_SIZE_MULT < 8)
-    //  BLOCK_LEN = 2^READ_BL_LEN, (READ_BL_LEN < 12)
+    //  BLOCK_LEN = 2^READ_BL_LEN, (READ_BL_LEN < 12)         
 
     int block_len = 1 << read_bl_len;
     int mult = 1 << (c_size_mult + 2);
@@ -459,7 +452,7 @@
     capacity = blocknr * block_len;
 
     int blocks = capacity / 512;
-
+        
     return blocks;
 }
 
@@ -467,10 +460,3 @@
 int SDFileSystem::disk_size() {
     return capacity;
 }
-
-void SDFileSystem::suspendStateChanged(unsigned int suspended) {
-    printf("st: %d\r\n", suspended);
-    _status = (suspended) ? 0 : 0x04;
-}
-
-