= GIET-VM / HBA Driver = 

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

The ''vci_multi_ahci'' component is a multi-channels, block oriented, external mass storage controller respecting the AHCI standard.

It is one of the physical disk driver that can be called by the generic IOC driver, and the SEG_IOC_BASE address must be defined in the hard_config.h file.

The addressable registers map is defined [source:soft/giet_vm/giet_drivers/hba_driver.h here]. 

 === unsigned int '''_hba_init'' ( unsigned int channel ) === 
This function initializes for a given channel
 *  the HBA hardware registers,
 *  the command list pointer,
 *  the command lists physical addresse,
 *  the command tables physical addresses array,

 === unsigned int '''_hba_write'''( unsigned int channel,   unsigned int mode,  unsigned int lba,  unsigned long long paddr,  unsigned int count ) ===    
This function register a write command in Command List and Command Table for a single physical buffer, and updates the HBA_PXCI register.
 * channel : channel index
 * mode :   BOOT / KERNEL / USER
 * lba :  logic bloc address on device
 * paddr : memory buffer physical base address
 * count : number of blocs
Returns 0 if success, > 0 if error.

 === unsigned int '''_hba_read'''( unsigned int channel,   unsigned int mode,  unsigned int lba,  unsigned long long paddr,  unsigned int count ) ===    
This function register a read command in Command List and Command Table for a single physical buffer, and updates the HBA_PXCI register.
 * channel : channel index
 * mode :   BOOT / KERNEL / USER
 * lba :  logic bloc address on device
 * paddr : memory buffer physical base address
 * count : number of blocs
Returns 0 if success, > 0 if error.

 === unsigned int '''_hba_get_block_size''' () ===
This function returns the block_size of HBA controller

 === unsigned int '''_hba_get_status'''( unsigned int   channel ) ===
This function returns the content of the HBA_PXIS register for a given channel,  and reset this register to acknoledge IRQ.
Return 0 if success, > 0 if error