ddi_dma_setup(9F) Kernel Functions for Drivers ddi_dma_setup(9F)
NAME
ddi_dma_setup - setup DMA resources
SYNOPSIS
#include <sys/ddi.h>
#include <sys/sunddi.h>
int ddi_dma_setup(dev_info_t *dip, ddi_dma_req_t *dmareqp, ddi_dma_handle_t *handlep);
INTERFACE LEVEL
This interface is obsolete. The functions ddi_dma_addr_bind_handle(9F), ddi_dma_alloc_handle(9F), ddi_dma_buf_bind_handle(9F),
ddi_dma_free_handle(9F), and ddi_dma_unbind_handle(9F) should be used instead.
PARAMETERS
dip A pointer to the device's dev_info structure.
dmareqp A pointer to a DMA request structure (see ddi_dma_req(9S)).
handlep A pointer to a DMA handle to be filled in. See below for a discussion of a handle. If handlep is NULL, the call to
ddi_dma_setup() is considered an advisory call, in which case no resources are allocated, but a value indicating the legal-
ity and the feasibility of the request is returned.
DESCRIPTION
ddi_dma_setup() allocates resources for a memory object such that a device can perform DMA to or from that object.
A call to ddi_dma_setup() informs the system that device referred to by dip wishes to perform DMA to or from a memory object. The memory
object, the device's DMA capabilities, the device driver's policy on whether to wait for resources, are all specified in the ddi_dma_req
structure pointed to by dmareqp.
A successful call to ddi_dma_setup() fills in the value pointed to by handlep. This is an opaque object called a DMA handle. This handle is
then used in subsequent DMA calls, until ddi_dma_free(9F) is called.
Again a DMA handle is opaque--drivers may not attempt to interpret its value. When a driver wants to enable its DMA engine, it must
retrieve the appropriate address to supply to its DMA engine using a call to ddi_dma_htoc(9F), which takes a pointer to a DMA handle and
returns the appropriate DMA address.
When DMA transfer completes, the driver should free up the the allocated DMA resources by calling ddi_dma_free().
RETURN VALUES
ddi_dma_setup() returns:
DDI_DMA_MAPPED Successfully allocated resources for the object. In the case of an advisory call, this indicates that the request
is legal.
DDI_DMA_PARTIAL_MAP Successfully allocated resources for a part of the object. This is acceptable when partial transfers are allowed
using a flag setting in the ddi_dma_req structure (see ddi_dma_req(9S) and ddi_dma_movwin(9F)).
DDI_DMA_NORESOURCES When no resources are available.
DDI_DMA_NOMAPPING The object cannot be reached by the device requesting the resources.
DDI_DMA_TOOBIG The object is too big and exceeds the available resources. The maximum size varies depending on machine and config-
uration.
CONTEXT
ddi_dma_setup() can be called from user or interrupt context, except when the dmar_fp member of the ddi_dma_req structure pointed to by
dmareqp is set to DDI_DMA_SLEEP, in which case it can be called from user context only.
ATTRIBUTES
See attributes(5) for a description of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Stability Level |Obsolete |
+-----------------------------+-----------------------------+
SEE ALSO
attributes(5), ddi_dma_addr_bind_handle(9F), ddi_dma_alloc_handle(9F), ddi_dma_buf_bind_handle(9F), ddi_dma_free_handle(9F),
ddi_dma_unbind_handle(9F)ddi_dma_addr_setup(9F), ddi_dma_buf_setup(9F), ddi_dma_free(9F), ddi_dma_htoc(9F), ddi_dma_movwin(9F),
ddi_dma_sync(9F), ddi_dma_req(9S)
Writing Device Drivers
NOTES
The construction of the ddi_dma_req structure is complicated. Use of the provided interface functions such as ddi_dma_buf_setup(9F) simpli-
fies this task.
SunOS 5.10 27 Sep 2002 ddi_dma_setup(9F)