[wiki:Component SocLib Components General Index] 

= !VciDma =

== 1) Functional Description ==

This VCI component  moves data from 
a source memory buffer to a destination memory buffer. 
It is both a target and an initiator.
 * It is addressed as a target to be configured for a transfer.
 * It is acting as an initiator to do the transfer.

There is only one DMA context handled at a time.
An IRQ is optionally asserted when transfer is finished.
This hardware component checks for segmentation violation, and can be used
as a default target.

This component has 5 memory-mapped registers :

 * '''DMA_SRC''' (Read / Write)
It defines the physical address of the source buffer.

 * '''DMA_DST''' (Read / Write)
It defines the physical address of the destination buffer.

 * '''DMA_LEN''' (Read / Write)
It defines the length of transfer, in bytes. This register must be written after writing into 
registers DMA_SRC & DMA_DST, as the writing into the DMA_LEN register starts the transfer. 
This register gets back to 0 when transfer is finished.
This register can be used to test the DMA coprocessor status.

 * '''DMA_RESET''' (Write-only)
Writing any value into this pseudo-register makes a clean re-initialisation of the DMA coprocessor:
The on-going VCI transaction is completed before the coprocessor returns the IDLE state.
This write access must be used by the software ISR to aknowledge the DMA IRQ.

 * '''DMA_IRQ_DISABLED''' (Read / Write)
A non zero value disables the IRQ line. The reset value is disabled.

For extensibility issues, you should access the DMA using globally-defined offsets.

You should include file `soclib/dma.h` from your software, it
defines `DMA_SRC`, `DMA_DST`, `DMA_LEN`, `DMA_RESET`, `DMA_IRQ_DISABLED`.

Sample code:
{{{
#include "soclib/dma.h"

static const volatile void* dma = 0xc0000000;

void * memcpy(void *dst, const void *src, const size_t len)
{
    soclib_io_set( dma, DMA_DST, dst );
    soclib_io_set( dma, DMA_SRC, src );
    soclib_io_set( dma, DMA_LEN, len );
    while( soclib_io_get( dma, DMA_LEN ) )
        ;
    return dst;
}

}}}

(add -I/path/to/soclib/include to your compilation command-line)

== 2) Component definition & usage ==

source:trunk/soclib/soclib/module/infrastructure_component/dma_infrastructure/vci_dma/caba/metadata/vci_dma.sd

See [wiki:SoclibCc/VciParameters SoclibCc/VciParameters]
{{{
Uses( 'vci_dma' )
}}}

== 3) CABA  Implementation ==

=== CABA sources ===
 
 * interface : source:trunk/soclib/soclib/module/infrastructure_component/dma_infrastructure/vci_dma/caba/source/include/vci_dma.h
 * implementation : source:trunk/soclib/soclib/module/infrastructure_component/dma_infrastructure/vci_dma/caba/source/src/vci_dma.cpp

=== CABA Constructor parameters ===
{{{
VciDma(
     sc_module_name name,   //  Component Name
     const soclib::common::MappingTable &mt,   // MappingTable
     const soclib::common::IntTab &srcid,  // Initiator index
     const soclib::common::IntTab &tgtid,  // Target index
     const size_t burst_size );   //  Number of bytes transfered in a burst
}}}

===  CABA Ports ===

 * sc_in<bool> '''p_resetn''' : Global system reset
 * sc_in<bool> '''p_clk''' : Global system clock
 * soclib::caba::!VciTarget<vci_param> '''p_vci_target''' : The VCI target port
 * soclib::caba::!VciInitiator<vci_param> '''p_vci_initiator''' : The VCI initiator port
 * sc_out<bool> '''p_irq''' : Interrupt port

== 4) TLM-DT implementation ==

The TLM-DT implementation is not available yet.