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A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Kernel Functions for Drivers

ddi_dma_coff(9F)

INTERFACE LEVEL
PARAMETERS
DESCRIPTION
RETURN VALUES
CONTEXT
SEE ALSO

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);

PARAMETERS

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.

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.