/**
* Send the data p over interface netif
*
* @param netif the netif to send the data
* @param p the pbuf containing the data
* @return An error code
*/
static err_t eth_output(struct netif *netif, struct pbuf *p) {
/* Wait for previous DMA (one could also implement queueing here...) */
while (dma_running)
;
/*
* Free the memory
*/
if (active_dma != NULL) {
pbuf_free(active_dma);
#ifdef DEBUG_MALLOC
UARTprintf("%x %d free, %s:%d;\r\n", active_dma, debug_ctr++, __FILE__, __LINE__);
#endif
}
active_dma = p;
dma_running = 1;
/* Reserve the pbuf so that it is not free()d */
pbuf_ref(p);
char *buf = p->payload;
int len = p->len;
uint16_t *len_buf = (uint16_t*)buf;
*len_buf = len - PBUF_LINK_HLEN;
len += 2;
/**
* If this enters the infinite loop, the buffer is not correctly aligned!
*/
if (((unsigned long) buf & 3) != 0)
for (;;)
;
/* Ensure that DMA sends all the data (and up to 3 bytes garbage extra) */
while ((len & 3) != 0)
len++;
/*
* Configure the TX DMA channel to transfer the packet buffer.
*/
uDMAChannelTransferSet(UDMA_CHANNEL_ETH0TX, UDMA_MODE_AUTO,
buf, (void *) (ETH_BASE + MAC_O_DATA), len >> 2);
/*
* Enable the Ethernet Transmit DMA channel.
*/
uDMAChannelEnable(UDMA_CHANNEL_ETH0TX);
/*
* Issue a software request to start the channel running.
*/
uDMAChannelRequest(UDMA_CHANNEL_ETH0TX);
return ERR_OK;
}
//*****************************************************************************
//
// Configure the SysTick and SysTick interrupt with a period of 1 second.
//
//*****************************************************************************
int
main(void)
{
uint16_t i;
//
// Set the clocking to run directly from the external crystal/oscillator.
// (no ext 32k osc, no internal osc)
//
SysCtrlClockSet(false, false, SYS_CTRL_SYSDIV_32MHZ);
//
// Set IO clock to the same as system clock
//
SysCtrlIOClockSet(SYS_CTRL_SYSDIV_32MHZ);
//
// Set up the serial console to use for displaying messages. This is
// just for this example program and is not needed for Systick operation.
//
InitConsole();
//
// Display the setup on the console.
//
UARTprintf("DMA SW example mem to mem!\n");
//
// Fill Source buffer with some data
//
for(i=0; i<256; i++)
{
ucSourceBuffer[i] = '0' + (i % 10);
}
//
// Enable the uDMA controller.
//
uDMAEnable();
//
// Set the base for the channel control table.
//
uDMAControlBaseSet(&ucDMAControlTable[0]);
//
// No attributes must be set for a software-based transfer.
// The attributes are cleared by default, but are explicitly cleared
// here, in case they were set elsewhere.
//
uDMAChannelAttributeDisable(UDMA_CH30_SW, UDMA_ATTR_ALL);
//
// Now set up the characteristics of the transfer for
// 8-bit data size, with source and destination increments
// in bytes, and a byte-wise buffer copy. A bus arbitration
// size of 8 is used.
//
uDMAChannelControlSet(UDMA_CH30_SW | UDMA_PRI_SELECT,
UDMA_SIZE_8 | UDMA_SRC_INC_8 |
UDMA_DST_INC_8 | UDMA_ARB_8);
//
// The transfer buffers and transfer size are now configured.
// The transfer uses AUTO mode, which means that the
// transfer automatically runs to completion after the first
// request.
//
uDMAChannelTransferSet(UDMA_CH30_SW | UDMA_PRI_SELECT,
UDMA_MODE_AUTO, ucSourceBuffer, ucDestBuffer,
sizeof(ucDestBuffer));
//
// Enable Interrupt for DMA
//
IntEnable(INT_UDMA);
//
// Finally, the channel must be enabled. Because this is a
// software-initiated transfer, a request must also be made.
// The request starts the transfer.
//
uDMAChannelEnable(UDMA_CH30_SW);
uDMAChannelRequest(UDMA_CH30_SW);
//
// Put cpu to sleep and wait for interrupt (when DMA transfer is done)
//
SysCtrlSleep();
//
// Loop forever while the SysTick runs.
//
while(1)
{
}
}
