/*      $Id: at91pdc.c,v 1.3 2011/07/01 19:31:17 dyoung Exp $   */

#include <sys/types.h>
#include <sys/bus.h>
#include <arm/at91/at91pdcvar.h>

int at91pdc_alloc_fifo(bus_dma_tag_t dmat, at91pdc_fifo_t *fifo, int size,
                       int flags)
{
        bus_dma_segment_t segs;
        int rsegs;
        int err;
        int f;

        memset(fifo, 0, sizeof(*fifo));

        /* allocate map: */
        f = flags & (BUS_DMA_BUS1 | BUS_DMA_BUS2 | BUS_DMA_BUS3 | BUS_DMA_BUS4);
        err = bus_dmamap_create(dmat, size, 1, size, 0,
                                BUS_DMA_WAITOK | f,
                                &fifo->f_dmamap);
        if (err)
                goto fail_0;

        /* allocate DMA safe memory: */
        f |= flags & BUS_DMA_STREAMING;
        err = bus_dmamem_alloc(dmat, size, 0, size, &segs, 1, &rsegs,
                               BUS_DMA_WAITOK | f);
        if (err)
                goto fail_1;

        /* allocate virtual memory: */
        f |= flags & (BUS_DMA_COHERENT | BUS_DMA_NOCACHE);
        err = bus_dmamem_map(dmat, &segs, 1, size, &fifo->f_buf,
                             BUS_DMA_WAITOK | f);
        if (err)
                goto fail_2;

        /* connect physical to virtual memory: */
        f |= flags & (BUS_DMA_READ | BUS_DMA_WRITE);
        f &= ~(BUS_DMA_COHERENT | BUS_DMA_NOCACHE);
        err = bus_dmamap_load(dmat, fifo->f_dmamap, fifo->f_buf, size, NULL,
                              BUS_DMA_NOWAIT | f);
        if (err)
                goto fail_3;

        /* initialize rest of the structure: */
        fifo->f_buf_size = size;
        fifo->f_ndx = fifo->f_length = 0;

        fifo->f_buf_addr = fifo->f_dmamap->dm_segs[0].ds_addr;
        fifo->f_pdc_rd_ndx = fifo->f_pdc_wr_ndx = 0;
        fifo->f_pdc_space = fifo->f_buf_size;

        return 0;
fail_3:
        bus_dmamem_unmap(dmat, fifo->f_buf, size);  
fail_2:
        bus_dmamem_free(dmat, &segs, rsegs);
fail_1:
        bus_dmamap_destroy(dmat, fifo->f_dmamap);  
fail_0:
        return err;
}