[wiki:Component SocLib Components General Index] 

= !VciDma Functional Description =

This VCI component is both a target and an initiator.
 * Addressing as a target allows to configure it for a transfer.
 * Initiator will 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 cheks for segmentation violation, and can be used
as a default target.

= Memory region layout =

 * `DMA_SRC`: ADDRESS![3:0] = 0x0
The source of memory copy.

 * `DMA_DST`: ADDRESS![3:0] = 0x4 
The destination of memory copy

 * `DMA_LEN`: ADDRESS![3:0] = 0x8
Length of transfer, in bytes. Writing to this register initiates the transfer, you should write to it after src and dst.
This register gets back to 0 when transfer is finished.

 * `DMA_IRQ_ENABLED`: ADDRESS![3:0] = 0xC
  * Written to: A boolean enabling the IRQ line (0 is disabling)
  * Read from: A boolean indicating the completion of the transfer, (0 is completed)

= Component usage =

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

You should include file source:trunk/soclib/include/soclib/dma.h from your software, it
defines `DMA_SRC`, `DMA_DST`, `DMA_LEN`, `DMA_IRQ_ENABLED`.

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

static const volatile void* dma_address = 0xc0000000;

void * memcpy(void *dst, const void *src, const size_t len)
{
    volatile int *dma = ((int*)dma_address);

    dma[DMA_DST] = (uint32_t)dst;
    dma[DMA_SRC] = (uint32_t)dma;
    dma[DMA_LEN] = (uint32_t)len;
    while ( dma[DMA_LEN] )
        ;
    return dst;
}

}}}

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

= Component definition =

Available in source:trunk/soclib/desc/soclib/vci_dma.sd

== Usage ==

!VciDma has no other parameter than VCI ones, it may be used like others, see [wiki:SoclibCc/VciParameters SoclibCc/VciParameters]
{{{
Uses( 'vci_dma', **vci_parameters )
}}}

= !VciDma CABA  Implementation =

The caba implementation is in 
 * source:trunk/soclib/systemc/include/caba/target/vci_dma.h
 * source:trunk/soclib/systemc/src/caba/target/vci_dma.cc

== Template parameters: ==

 * The VCI parameters

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

== 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