= GIET_VM / PIC Driver =

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

The ''vci_pic'' component is a multi-channels interrupt controller, available in the SoCLib components library. This component translate an hardware interrupt generated by an external peripheral (HWI) to a write-triggered interrupt (WTI) that will be sent to an internal ''vci_xcu'' in a given cluster. The PIC component is therefore an external, non replicated peripheral.  

The virtual base address of the segment associated to the component is:
    vbase =  SEG_PIC_BASE + cluster_io << 32

The SEG_PIC_BASE value must be defined in the hard_config.h file.

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



 === void '''_pic_set_register'''( unsigned int channel,   unsigned int index,   unsigned int value ) ===
This low level function set a new value in register (channel / index).

 === unsigned int '''_pic_get_register'''( unsigned int channel,   unsigned int index ) ===
This low level function returns the value of register (channel / index).

 === void '''_pic_init'''( unsigned int channel,  unsigned int vaddr,  unsigned int extend ) ===
This function initializes and activates a given channel (i.e. a given external IRQ) in the PIC component. It writes an XCU mailbox physical address in  the IOPIC_ADDR and IOPIC_EST registers, and writes a non-zero value in IOPIC_MASK register.
 * channel : source PIC HWI channel
 * vaddr :  address of the destination XCU register
 * extend :  cluster_xy for the destination XCU

 === unsigned int '''_pic_get_status'''( unsigned int channel ) === 
This function returns the status of a given HWI channel.