Posted on May 17, 2011 at 09:49That is essentially what we do (but in reverse):
* external device writes to asynchronous FIFO part
* STR912 DMA via EMI to SRAM (in 1k chunks)
* then use ENET library
ENET_TxPkt( void * ppkt, u16 size )which I've modified to have multiple ENET descriptors (note: search for other threads regarding this)
void ENET_TxDscrInit(void)
{
u32 currIndex; // index to the current descriptor
u32 nextIndex = 0; // index to the start of the next descriptor in the
// chain
u8 * pNextBuffer; // pointer to the RX next buffer in memeory
ENET_DMADSCRBase * pCurrentDescr;
ENET_DMADSCRBase * pNextDescr;
for ( currIndex = 0; currIndex < NUM_TX_BUFFERS; ++currIndex )
{
if ( (++nextIndex) == NUM_TX_BUFFERS ) // for the last descriptor
nextIndex = 0; // loop back to the first buffer.
pCurrentDescr = &dmaTxDscrBase[ currIndex ];
pNextDescr = &dmaTxDscrBase[ nextIndex ];
pNextBuffer = (u8*)(TxBuff + (currIndex * EMAC_MAX_PACKET_SIZE));
/* Initialize ENET status and control */
pCurrentDescr->dmaStatCntl = 0;
/* ENET Start Address */
pCurrentDescr->dmaAddr = (u32)pNextBuffer;
/* Next Descriptor Address */
pCurrentDescr->dmaNext = (u32)pNextDescr | DMA_DSCR_NXT_NPOL_EN;
/* Setting the VALID bit */
pCurrentDescr->dmaPackStatus = 0;//DMA_DSCR_TX_STATUS_VALID_MSK;
}
TxDscrIndex = 0;
/* Tx next set to Tx decriptor base */
ENET_DMA->TXNDAR = (u32)&(dmaTxDscrBase);
/* Enable next enable */
ENET_DMA->TXNDAR |= DMA_DSCR_NXT_NPOL_EN;
}
