ddi_dma_coff(9F)

NAME

ddi_dma_coff − convert a DMA cookie to an offset within a DMA handle

SYNOPSIS

#include <sys/conf.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
int ddi_dma_coff(ddi_dma_handle_t handle
, ddi_dma_cookie_t ∗cookiep, off_t ∗offp)

ARGUMENTS

handle The handle filled in by a call to ddi_dma_setup(9F).

cookiep A pointer to a DMA cookie (see ddi_dma_cookie(9S)) that contains the appropriate address, length and bus type to be used in programming the DMA engine.

offp A pointer to an offset to be filled in.

INTERFACE LEVEL

SPARC architecture specific (SPARC DDI).

DESCRIPTION

ddi_dma_coff() converts the values in DMA cookie pointed to by cookiep to an offset (in bytes) from the beginning of the object that the DMA handle has mapped.

ddi_dma_coff() allows a driver to update a DMA cookie with values it reads from its device’s DMA engine after a transfer completes and convert that value into an offset into the object that is mapped for DMA.

RETURN VALUES

ddi_dma_coff() returns:

DDI_SUCCESS
Successfully filled in offp.

DDI_FAILURE
Failed to successfully fill in offp.

CONTEXT

ddi_dma_coff() can be called from user or interrupt context.

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