/**
* \ingroup sd_raw
* Writes a continuous data stream obtained from a callback function.
*
* This function starts writing at the specified offset. To obtain the
* next bytes to write, it calls the callback function. The callback fills the
* provided data buffer and returns the number of bytes it has put into the buffer.
*
* By returning zero, the callback may stop writing.
*
* \param[in] offset Offset where to start writing.
* \param[in] buffer Pointer to a buffer which is used for the callback function.
* \param[in] length Number of bytes to write in total. May be zero for endless writes.
* \param[in] callback The function used to obtain the bytes to write.
* \param[in] p An opaque pointer directly passed to the callback function.
* \returns 0 on failure, 1 on success
* \see sd_raw_read_interval, sd_raw_write, sd_raw_read
*/
uint8_t sd_raw_write_interval(offset_t offset, uint8_t* buffer, uintptr_t length, sd_raw_write_interval_handler_t callback, void* p)
{
#if SD_RAW_SAVE_RAM
#error "SD_RAW_WRITE_SUPPORT is not supported together with SD_RAW_SAVE_RAM"
#endif
if(!buffer || !callback)
return 0;
uint8_t endless = (length == 0);
while(endless || length > 0)
{
uint16_t bytes_to_write = callback(buffer, offset, p);
if(!bytes_to_write)
break;
if(!endless && bytes_to_write > length)
return 0;
/* as writing is always buffered, we directly
* hand over the request to sd_raw_write()
*/
if(!sd_raw_write(offset, buffer, bytes_to_write))
return 0;
offset += bytes_to_write;
length -= bytes_to_write;
}
return 1;
}
/**
* \ingroup sd_raw
* Writes a continuous data stream obtained from a callback function.
*
* This function starts writing at the specified offset. To obtain the
* next bytes to write, it calls the callback function. The callback fills the
* provided data buffer and returns the number of bytes it has put into the buffer.
*
* By returning zero, the callback may stop writing.
*
* \param[in] offset Offset where to start writing.
* \param[in] buffer Pointer to a buffer which is used for the callback function.
* \param[in] length Number of bytes to write in total. May be zero for endless writes.
* \param[in] callback The function used to obtain the bytes to write.
* \param[in] p An opaque pointer directly passed to the callback function.
* \returns 0 on failure, 1 on success
* \see sd_raw_read_interval, sd_raw_write, sd_raw_read
*/
uint8_t sd_raw_write_interval(offset_t offset, uint8_t* buffer, uintptr_t length, sd_raw_write_interval_handler_t callback, void* p)
{
if(!buffer || !callback)
return 0;
uint8_t endless = (length == 0);
while(endless || length > 0)
{
uint16_t bytes_to_write = callback(buffer, offset, p);
if(!bytes_to_write)
break;
if(!endless && bytes_to_write > length)
return 0;
/* as writing is always buffered, we directly
* hand over the request to sd_raw_write()
*/
if(!sd_raw_write(offset, buffer, bytes_to_write))
return 0;
offset += bytes_to_write;
length -= bytes_to_write;
}
return 1;
}
/**
* \ingroup sd_raw
* Writes the write buffer's content to the card.
*
* \note When write buffering is enabled, you should
* call this function before disconnecting the
* card to ensure all remaining data has been
* written.
*
* \returns 0 on failure, 1 on success.
* \see sd_raw_write
*/
uint8_t sd_raw_sync()
{
#if SD_RAW_WRITE_BUFFERING
if(raw_block_written)
return 1;
if(!sd_raw_write(raw_block_address, raw_block, sizeof(raw_block)))
return 0;
raw_block_written = 1;
#endif
return 1;
}
/**
* \ingroup sd_raw
* Writes raw data to the card.
*
* \note If write buffering is enabled, you might have to
* call sd_raw_sync() before disconnecting the card
* to ensure all remaining data has been written.
*
* \param[in] offset The offset where to start writing.
* \param[in] buffer The buffer containing the data to be written.
* \param[in] length The number of bytes to write.
* \returns 0 on failure, 1 on success.
* \see sd_raw_write_interval, sd_raw_read, sd_raw_read_interval
*/
uint8_t sd_raw_write(uint32_t offset, const uint8_t* buffer, uint16_t length)
{
#if SD_RAW_WRITE_SUPPORT
if(get_pin_locked())
return 0;
uint32_t block_address;
uint16_t block_offset;
uint16_t write_length;
uint16_t i;
while(length > 0)
{
/* determine byte count to write at once */
block_address = offset & 0xfffffe00;
block_offset = offset & 0x01ff;
write_length = 512 - block_offset; /* write up to block border */
if(write_length > length)
write_length = length;
/* Merge the data to write with the content of the block.
* Use the cached block if available.
*/
if(block_address != raw_block_address)
{
#if SD_RAW_WRITE_BUFFERING
if(!raw_block_written)
{
if(!sd_raw_write(raw_block_address, raw_block, sizeof(raw_block)))
return 0;
}
#endif
if(block_offset || write_length < 512)
{
if(!sd_raw_read(block_address, raw_block, sizeof(raw_block)))
return 0;
}
raw_block_address = block_address;
}
if(buffer != raw_block)
{
memcpy(raw_block + block_offset, buffer, write_length);
#if SD_RAW_WRITE_BUFFERING
raw_block_written = 0;
if(length == write_length)
return 1;
#endif
}
buffer += write_length;
/* address card */
select_card();
/* send single block request */
if(sd_raw_send_command_r1(CMD_WRITE_SINGLE_BLOCK, block_address))
{
unselect_card();
return 0;
}
/* send start byte */
sd_raw_send_byte(0xfe);
/* write byte block */
uint8_t* cache = raw_block;
for(i = 0; i < 512; ++i)
sd_raw_send_byte(*cache++);
/* write dummy crc16 */
sd_raw_send_byte(0xff);
sd_raw_send_byte(0xff);
/* wait while card is busy */
while(sd_raw_rec_byte() != 0xff);
sd_raw_rec_byte();
/* deaddress card */
unselect_card();
length -= write_length;
offset += write_length;
#if SD_RAW_WRITE_BUFFERING
raw_block_written = 1;
#endif
}
return 1;
#else
return 0;
#endif
}
/**
* \ingroup sd_raw
* Reads raw data from the card.
*
* \param[in] offset The offset from which to read.
* \param[out] buffer The buffer into which to write the data.
* \param[in] length The number of bytes to read.
* \returns 0 on failure, 1 on success.
* \see sd_raw_read_interval, sd_raw_write, sd_raw_write_interval
*/
uint8_t sd_raw_read(uint32_t offset, uint8_t* buffer, uint16_t length)
{
uint32_t block_address;
uint16_t block_offset;
uint16_t read_length;
uint16_t i;
while(length > 0)
{
/* determine byte count to read at once */
block_address = offset & 0xfffffe00;
block_offset = offset & 0x01ff;
read_length = 512 - block_offset; /* read up to block border */
if(read_length > length)
read_length = length;
#if !SD_RAW_SAVE_RAM
/* check if the requested data is cached */
if(block_address != raw_block_address)
#endif
{
#if SD_RAW_WRITE_BUFFERING
if(!raw_block_written)
{
if(!sd_raw_write(raw_block_address, raw_block, sizeof(raw_block)))
return 0;
}
#endif
/* address card */
select_card();
/* send single block request */
if(sd_raw_send_command_r1(CMD_READ_SINGLE_BLOCK, block_address))
{
unselect_card();
return 0;
}
/* wait for data block (start byte 0xfe) */
i = 0;
while(sd_raw_rec_byte() != 0xfe) {
i++;
if (i == 0) {
unselect_card();
return 0;
}
}
#if SD_RAW_SAVE_RAM
/* read byte block */
uint16_t read_to = block_offset + read_length;
for(i = 0; i < 512; ++i)
{
uint8_t b = sd_raw_rec_byte();
if(i >= block_offset && i < read_to)
*buffer++ = b;
}
#else
/* read byte block */
uint8_t* cache = raw_block;
for(i = 0; i < 512; ++i)
*cache++ = sd_raw_rec_byte();
raw_block_address = block_address;
memcpy(buffer, raw_block + block_offset, read_length);
buffer += read_length;
#endif
/* read crc16 */
sd_raw_rec_byte();
sd_raw_rec_byte();
/* deaddress card */
unselect_card();
/* let card some time to finish */
sd_raw_rec_byte();
}
#if !SD_RAW_SAVE_RAM
else
{
/* use cached data */
memcpy(buffer, raw_block + block_offset, read_length);
buffer += read_length;
}
#endif
length -= read_length;
offset += read_length;
}
return 1;
}
