= GIET-VM / SDC Driver = 

[[PageOutline]]

The [source:soft/giet_vm/giet_drivers/sdc_driver.c sdc_driver.c] and [source:soft/giet_vm/giet_drivers/sdc_driver.h sdc_driver.h] files define the SDC driver. 

This component is a single channel, block oriented, external mass storage peripheral, implemented on a SD card. 

The ''sdc_driver'' uses the lower level ''spi_driver'' to access the SD card.

The ''sdc_driver'' is called by the generic ''ioc_driver'' when the USE_IOC_SPI flag is set in the hard_config.h file. 

The SEG_IOC_BASE address must be defined in the hard_config.h file.

In this implementation, the SDC peripheral is acting as a target (no DMA capability) :  the '''_sdc_read()''' and '''_sdc_write()''' are blocking until the transfer is fully completed, and does not use any interrupt to signal completion.

WARNING : The '''_sdc_write()''' function is not implemented yet



 === unsigned int '''_sdc_init'''() ===
This function initializes the SPI controller and call sdc_open to initialize  the SD card.
Returns 0 if success, >0 if failure

 === unsigned int '''_sdc_read'''( unsigned int mode,   unsigned int lba,  paddr_t buffer,  unsigned int count ) ===
Transfer data from the SD card to a memory buffer. 
 * mode     : BOOT / KERNEL / USER (Not used in this implementation)
 * lba      : first block index on the SD card
 * buffer   : physical base address of the memory buffer 
 * count    : number of blocks to be transfered.
Returns 0 if success, > 0 if error.

 === unsigned int '''_sdc_write'''( unsigned int mode,   unsigned int lba,  paddr_t buffer,  unsigned int count ) ===
Transfer data from a memory buffer to the SD card. 
 * mode     : BOOT / KERNEL / USER (Not used in this implementation)
 * lba      : first block index on the SD card.
 * buffer   : physical base address of the memory buffer 
 * count    : number of blocks to be transfered.
Returns 0 if success, > 0 if error.
WARNING: The _sdc_write() is not implemented yet.

 === unsigned int '''_sdc_get_status'''() ===
 This function should not be called for this implementation of the SDC driver (No DMA).

 === unsigned int '''_sdc_get_block_size'''() ===
Returns the block size (bytes).