Hi!

	I am writing a code as given bellow to get a data buffer of one
page size from DMA memory.
I want the data buffer to be 4 byte aligned hence I am passing the fifth
argument in the create function as the alignment. But the
bus_dmamap_load fails returning EFBIG.

If I pass the alignment argument as 0 in the bus_dmamap_create function
the call to bus_dmamap_load succeeds.

Could any one please tell me whre am I making a mistake in this....

Thanking u in advance=20

Regards,

Nitin=20


struct my_softc {
	struct device if_device;
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	uint8_t phy_addr;
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	u_int32_t ebase_addr;

	struct mips_bus_dma_tag sc_eth_dmat;
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	bus_dma_segment_t 	sc_eth_dmaseg_data;
	int			sc_eth_dmanseg_data;

	bus_dmamap_t Data_Buf_dmamap;

	caddr_t Data_Buff;

};        =20

struct my_softc sc;

caddr_t data_buff;

/*Following code is inside attach.*/

	/*Allocate DMA-safe memory for the data buffers.*/
	if ((error =3D bus_dmamem_alloc(&sc->sc_eth_dmat,
	    /*RX_BUF_PAGES*/PAGE_SIZE, PAGE_SIZE, PAGE_SIZE ,
&sc->sc_eth_dmaseg_data, 1,
		&sc->sc_eth_dmanseg_data,BUS_DMA_NOWAIT)) !=3D 0) {
		printf("%s: can't allocate data buffer, error =3D %d\n",
		       sc->if_device.dv_xname, error);
		return error;
	}
	printf("MAP DMA-safe memory for the data buffers.\n");
	/*Allocate DMA-safe memory for the data buffers.*/
	if ((error =3D bus_dmamem_map(&sc->sc_eth_dmat,
&sc->sc_eth_dmaseg_data, sc->sc_eth_dmanseg_data,
	    /*RX_BUF_PAGES*/PAGE_SIZE,(caddr_t *)&sc->Data_Buff,
	    BUS_DMA_NOWAIT|BUS_DMA_COHERENT)) !=3D 0) {
		printf("%s: can't map data buffer, error =3D %d\n",
		       sc->if_device.dv_xname, error);
		bus_dmamem_free(&sc->sc_eth_dmat,
&sc->sc_eth_dmaseg_data, sc->sc_eth_dmanseg_data);
		return error;
	}

	data_buff =3D sc->Data_Buff;
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		if ((error =3D bus_dmamap_create(&sc->sc_eth_dmat,
	    PAGE_SIZE, 1, PAGE_SIZE, 4, BUS_DMA_NOWAIT,
	    &sc->Data_Buf_dmamap[i])) !=3D 0) {
		printf("%s: can't create data buffer DMA map, error =3D
%d\n",
		       sc->if_device.dv_xname, error);
				return error;
		}

		if ((error =3D bus_dmamap_load(&sc->sc_eth_dmat,
sc->Data_Buf_dmamap[i],
	    data_buff, PAGE_SIZE,
	    NULL, BUS_DMA_READ | BUS_DMA_NOWAIT)) !=3D 0) {
		printf("%s: can't load data buffer DMA map, error =3D
%d\n",
		       sc->if_device.dv_xname, error);
			return error;
		}
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