ddi_dma_addr_bind_handle - binds an address to a DMA handle
int ddi_dma_addr_bind_handle(ddi_dma_handle_t handle, struct as *as,
caddr_t addr, size_t len, uint_t flags, int (*callback) (caddr_t) ,
caddr_t arg, ddi_dma_cookie_t *cookiep, uint_t *ccountp);
illumos DDI specific (illumos DDI).
A pointer to an address space structure. This parameter
should be set to NULL, which implies kernel address space.
Virtual address of the memory object.
Length of the memory object in bytes.
Valid flags include:
Transfer direction is from memory to I/O.
Transfer direction is from I/O to memory.
Both read and write.
Establish an MMU redzone at end of the
Partial resource allocation.
Nonsequential, random, and small block transfers.
Sequential, unidirectional, block-sized, and
The address of a function to call back later if resources
are not currently available. The following special function addresses may also
Wait until resources are available.
Do not wait until resources are available and do not
schedule a callback.
Argument to be passed to the callback function,
callback, if such a function is specified.
A pointer to the first ddi_dma_cookie(9S)
structure. This should be left as NULL
in new callers.
ddi_dma_addr_bind_handle() allocates DMA resources for a memory
object such that a device can perform DMA to or from the object.
DMA resources are allocated considering the device's DMA
attributes as expressed by ddi_dma_attr(9S) (see
Upon a successful return, ccountp
points to a
value representing the number of cookies for this DMA
object. This can
be left as NULL
in new callers. The cookie count can be obtained by
ddi_dma_addr_bind_handle() allocates and associates a
number of DMA cookies with handle. To get the total number of
cookies, callers should use the ddi_dma_ncookies(9F) function. To get
all of the cookies, callers should use the ddi_dma_cookie_iter(9F) or
ddi_dma_cookie_get(9F) functions. Callers should pass NULL for
cookiep and ccountp. These values are required if using the
deprecated ddi_dma_nextcookie(9F) interface, in which case
cookiep is filled in with the first ddi_dma_cookie(9S)
When a DMA transfer completes, the driver frees up system
DMA resources by calling ddi_dma_unbind_handle(9F).
The flags argument contains information for mapping
These flags describe the intended direction of the
This flag should be set if the device is doing
sequential, unidirectional, block-sized, and block-aligned transfers to or
from memory. The alignment and padding constraints specified by the
fields in the DMA
used to allocate the most effective hardware support for large
This flag should be set if the device accesses memory
randomly, or if synchronization steps using ddi_dma_sync(9F)
need to be
as efficient as possible. I/O parameter blocks used for communication between
a device and a driver should be allocated using
If this flag is set, the system attempts to establish a
protected red zone after the object. The DMA resource allocation
functions do not guarantee the success of this request as some implementations
may not have the hardware ability to support a red zone.
Setting this flag indicates the caller can accept
resources for part of the object. That is, if the size of the object exceeds
the resources available, only resources for a portion of the object are
allocated. The system indicates this condition by returning status
. At a later point, the caller can use
to change the valid portion of the object for which
resources are allocated. If resources were allocated for only part of the
returns resources for the first
window. Even when DDI_DMA_PARTIAL
is set, the system may
decide to allocate resources for the entire object (less overhead) in which
The callback function callback indicates how a caller wants
to handle the possibility of resources not being available. If
callback is set to DDI_DMA_DONTWAIT, the caller does not care
if the allocation fails, and can handle an allocation failure appropriately.
If callback is set to DDI_DMA_SLEEP, the caller wishes to have
the allocation routines wait for resources to become available. If any other
value is set and a DMA resource allocation fails, this value is
assumed to be the address of a function to be called when resources become
available. When the specified function is called, arg is passed to it
as an argument. The specified callback function must return either
DDI_DMA_CALLBACK_RUNOUT or DDI_DMA_CALLBACK_DONE.
DDI_DMA_CALLBACK_RUNOUT indicates that the callback function
attempted to allocate DMA resources but failed. In this case, the
callback function is put back on a list to be called again later.
DDI_DMA_CALLBACK_DONE indicates that either the allocation of
DMA resources was successful or the driver no longer wishes to
The callback function is called in interrupt context. Therefore,
only system functions accessible from interrupt context are be available.
The callback function must take whatever steps are necessary to protect its
critical resources, data structures, queues, and so on.
Successfully allocated resources for the entire
Successfully allocated resources for a part of the
object. This is acceptable when partial transfers are permitted by setting the
DDI_DMA_PARTIAL flag in flags.
Another I/O transaction is using the DMA
No resources are available at the present time.
The object cannot be reached by the device requesting the
The object is too big. A request of this size can never
be satisfied on this particular system. The maximum size varies depending on
machine and configuration.
ddi_dma_addr_bind_handle() can be called from user, kernel, or interrupt
context, except when callback is set to DDI_DMA_SLEEP, in which
case it can only be called from user or kernel context.
Writing Device Drivers
If the driver permits partial mapping with the DDI_DMA_PARTIAL flag, the
number of cookies in each window may exceed the size of the device's
scatter/gather list as specified in the dma_attr_sgllen field in the
ddi_dma_attr(9S) structure. In this case, each set of cookies
comprising a DMA window will satisfy the DMA attributes as
described in the ddi_dma_attr(9S) structure in all aspects. The driver
should set up its DMA engine and perform one transfer for each set of
cookies sufficient for its scatter/gather list, up to the number of cookies
for this window, before advancing to the next window using