Merge pull request #8573 from deepikabhavnani/flag_Crc

Compile time config flag MBED_CONF_SD_CRC_ENABLED for CRC in SD

Author: Cruz Monrreal

components/storage/blockdevice/COMPONENT_SD/SDBlockDevice.cpp

@@ -247,9 +247,15 @@
 // Only HC block size is supported. Making this a static constant reduces code size.
 const uint32_t SDBlockDevice::_block_size = BLOCK_SIZE_HC;
 
+#if MBED_CONF_SD_CRC_ENABLED
 SDBlockDevice::SDBlockDevice(PinName mosi, PinName miso, PinName sclk, PinName cs, uint64_t hz, bool crc_on)
     : _sectors(0), _spi(mosi, miso, sclk), _cs(cs), _is_initialized(0),
-      _crc_on(crc_on), _init_ref_count(0), _crc16(0, 0, false, false)
+      _init_ref_count(0), _crc_on(crc_on), _crc16(0, 0, false, false)
+#else
+SDBlockDevice::SDBlockDevice(PinName mosi, PinName miso, PinName sclk, PinName cs, uint64_t hz, bool crc_on)
+    : _sectors(0), _spi(mosi, miso, sclk), _cs(cs), _is_initialized(0),
+      _init_ref_count(0)
+#endif
 {
     _cs = 1;
     _card_type = SDCARD_NONE;
@@ -293,10 +299,12 @@ int SDBlockDevice::_initialise_card()
         return status;
     }
 
+#if MBED_CONF_SD_CRC_ENABLED
     if (_crc_on) {
         // Enable CRC
         status = _cmd(CMD59_CRC_ON_OFF, _crc_on);
     }
+#endif
 
     // Read OCR - CMD58 Response contains OCR register
     if (BD_ERROR_OK != (status = _cmd(CMD58_READ_OCR, 0x0, 0x0, &response))) {
@@ -350,10 +358,15 @@ int SDBlockDevice::_initialise_card()
         debug_if(SD_DBG, "Card Initialized: Version 1.x Card\n");
     }
 
+#if MBED_CONF_SD_CRC_ENABLED
     if (!_crc_on) {
         // Disable CRC
         status = _cmd(CMD59_CRC_ON_OFF, _crc_on);
     }
+#else
+    status = _cmd(CMD59_CRC_ON_OFF, 0);
+#endif
+
     return status;
 }
 
@@ -649,7 +662,6 @@ uint8_t SDBlockDevice::_cmd_spi(SDBlockDevice::cmdSupported cmd, uint32_t arg)
 {
     uint8_t response;
     char cmdPacket[PACKET_SIZE];
-    uint32_t crc;
 
     // Prepare the command packet
     cmdPacket[0] = SPI_CMD(cmd);
@@ -658,10 +670,14 @@ uint8_t SDBlockDevice::_cmd_spi(SDBlockDevice::cmdSupported cmd, uint32_t arg)
     cmdPacket[3] = (arg >> 8);
     cmdPacket[4] = (arg >> 0);
 
+#if MBED_CONF_SD_CRC_ENABLED
+    uint32_t crc;
     if (_crc_on) {
         _crc7.compute((void *)cmdPacket, 5, &crc);
         cmdPacket[5] = (char)(crc | 0x01);
-    } else {
+    } else
+#endif
+    {
         // CMD0 is executed in SD mode, hence should have correct CRC
         // CMD8 CRC verification is always enabled
         switch (cmd) {
@@ -874,6 +890,7 @@ int SDBlockDevice::_read_bytes(uint8_t *buffer, uint32_t length)
     crc = (_spi.write(SPI_FILL_CHAR) << 8);
     crc |= _spi.write(SPI_FILL_CHAR);
 
+#if MBED_CONF_SD_CRC_ENABLED
     if (_crc_on) {
         uint32_t crc_result;
         // Compute and verify checksum
@@ -885,6 +902,7 @@ int SDBlockDevice::_read_bytes(uint8_t *buffer, uint32_t length)
             return SD_BLOCK_DEVICE_ERROR_CRC;
         }
     }
+#endif
 
     _deselect();
     return 0;
@@ -907,6 +925,7 @@ int SDBlockDevice::_read(uint8_t *buffer, uint32_t length)
     crc = (_spi.write(SPI_FILL_CHAR) << 8);
     crc |= _spi.write(SPI_FILL_CHAR);
 
+#if MBED_CONF_SD_CRC_ENABLED
     if (_crc_on) {
         uint32_t crc_result;
         // Compute and verify checksum
@@ -917,6 +936,7 @@ int SDBlockDevice::_read(uint8_t *buffer, uint32_t length)
             return SD_BLOCK_DEVICE_ERROR_CRC;
         }
     }
+#endif
 
     return 0;
 }
@@ -933,10 +953,12 @@ uint8_t SDBlockDevice::_write(const uint8_t *buffer, uint8_t token, uint32_t len
     // write the data
     _spi.write((char *)buffer, length, NULL, 0);
 
+#if MBED_CONF_SD_CRC_ENABLED
     if (_crc_on) {
         // Compute CRC
         _crc16.compute((void *)buffer, length, &crc);
     }
+#endif
 
     // write the checksum CRC16
     _spi.write(crc >> 8);

components/storage/blockdevice/COMPONENT_SD/SDBlockDevice.h

@@ -218,11 +218,13 @@ class SDBlockDevice : public BlockDevice {
     uint32_t _erase_size;
     bool _is_initialized;
     bool _dbg;
-    bool _crc_on;
     uint32_t _init_ref_count;
 
+#if MBED_CONF_SD_CRC_ENABLED
+    bool _crc_on;
     mbed::MbedCRC<POLY_7BIT_SD, 7> _crc7;
     mbed::MbedCRC<POLY_16BIT_CCITT, 16> _crc16;
+#endif
 };
 
 #endif  /* DEVICE_SPI */

components/storage/blockdevice/COMPONENT_SD/config/mbed_lib.json

@@ -8,7 +8,8 @@
         "FSFAT_SDCARD_INSTALLED": 1,
         "CMD_TIMEOUT": 10000,
         "CMD0_IDLE_STATE_RETRIES": 5,
-        "SD_INIT_FREQUENCY": 100000
+        "INIT_FREQUENCY": 100000,
+        "CRC_ENABLED": 1
     },
     "target_overrides": {
         "DISCO_F051R8": {