Dmacallback - Analog Devices VisualDSP++ 5.0 Service Manual

Device Manager Design

DMACallback

The
DMACallback
DMA manager for devices that are supported by peripheral DMA.
Assuming error checking is enabled, the device handle is validated first.
The function then determines the event that has occurred and performs its
processing based on the event type.
If the event indicates that a descriptor has been processed, the processed
flag and processed count fields of the buffer are updated. The application's
callback function is then invoked in order to notify the application of the
event.
If the event indicates that DMA processing has generated the
EVENT_SUBBUFFER_PROCESSED
callback into the application, stating that a sub-buffer has completed pro-
cessing. If the event indicates that DMA processing has generated the
DEV_EVENT_BUFFER_PROCESSED
callback into the application, stating that the entire buffer has completed
processing.
The DMA manager reports asynchronous DMA errors via the callback
mechanism. There errors are, in turn, passed back to the client via its
callback function.
Note that in this routine (and the
manager calls the client callback function directly, without concern for
whether live callbacks are in effect. It can do this as the DMA manager is
passed the handle to the deferred callback service as part of the
function. As such, if the deferred callback service is in use, the invo-
Open
cation of the
DMACallback
the DMA manager. In this way, the
the client's callback function.
10-42
function is called in response to DMA events from the
event, the function makes the appropriate
event, the function makes the appropriate
PDDCallback
function in the device manager is deferred by
dmaCallback
VisualDSP++ 5.0 Device Drivers and System
Services Manual for Blackfin Processors
ADI_DEV_
function), the device
adi_dma_
function can directly call
ADI_