Typical operation example:
Network device driver call flow:
/* Get xDMA controller */ sc->xdma_tx = xdma_ofw_get(sc->dev, "tx"); /* Allocate virtual channel */ sc->xchan_tx = xdma_channel_alloc(sc->xdma_tx, caps);
int
atse_xdma_tx_intr(void *arg, xdma_transfer_status_t *status)
{
for (;;) {
err = xdma_dequeue_mbuf(sc->xchan_tx, &m, &st);
if (err != 0) {
break;
}
}
}
/* Setup interrupt handler. */
xdma_setup_intr(sc->xchan_tx, atse_xdma_tx_intr, sc, &sc->ih_tx);
/* Prepare SG transfer */
xdma_prep_sg(sc->xchan_tx, TX_QUEUE_SIZE);/* Enqueue (multiple) mbufs to receive */ m = m_getcl(); xdma_enqueue_mbuf(sc->xchan_rx, &m, 0, 4, 4, XDMA_DEV_TO_MEM); m = m_getcl(); xdma_enqueue_mbuf(sc->xchan_rx, &m, 0, 4, 4, XDMA_DEV_TO_MEM); ... xdma_queue_submit(sc->xchan_rx);
/* Enqueue mbuf to transmit */ xdma_enqueue_mbuf(sc->xchan_tx, &m, 0, 4, 4, XDMA_MEM_TO_DEV); xdma_queue_submit(sc->xchan_tx);
DMA engine driver functions:
/* Prepare a channel for SG transfer */
softdma_channel_prep_sg(device_t dev, struct xdma_channel *xchan)
{
...
}
/* Submit sg list */
softdma_channel_submit_sg(device_t dev, struct xdma_channel *xchan,
struct xdma_sglist *sg, uint32_t sg_n)
{
...
}
/* Provide the amount of free entries for requests. */
softdma_channel_capacity(device_t dev, xdma_channel_t *xchan,
uint32_t *capacity)
{
...
}Example usage:
xDMA support for atse(4) D9618
mSGDMA driver D9619
SoftDMA® driver D9620
ARM PrimeCell® PL330 driver D10201
Cadence Quad SPI Flash driver D10245