Lines Matching refs:DMA

1 			DMA Engine API Guide
6 NOTE: For DMA Engine usage in async_tx please see:
10 Below is a guide to device driver writers on how to use the Slave-DMA API of the
11 DMA Engine. This is applicable only for slave DMA usage only.
13 The slave DMA usage consists of following steps:
14 1. Allocate a DMA slave channel
20 1. Allocate a DMA slave channel
22    Channel allocation is slightly different in the slave DMA context,
23    client drivers typically need a channel from a particular DMA
36    DMA channel.
43    return 'true' when the desired DMA channel is found.
50    Next step is always to pass some specific information to the DMA
51    driver.  Most of the generic information which a slave DMA can use
53    DMA direction, DMA addresses, bus widths, DMA burst lengths etc
56    If some DMA controllers have more parameters to be sent then they
73    DMA-engine are:
75    slave_sg	- DMA a list of scatter gather buffers from/to a peripheral
76    dma_cyclic	- Perform a cyclic DMA operation from/to a peripheral till the
101    the DMA operation prior to calling dmaengine_prep_slave_sg(), and must
102    keep the scatterlist mapped until the DMA operation has completed.
103    The scatterlist must be mapped using the DMA struct device.
105    called using the DMA struct device, too.
115    added and the descriptor must then be submitted.  Some DMA engine
123 	case for slave/cyclic DMA.
125 	For slave DMA, the subsequent transaction may not be available
127 	slave DMA callbacks are permitted to prepare and submit a new
130 	For cyclic DMA, a callback function may wish to terminate the
131 	DMA via dmaengine_terminate_all().
133 	Therefore, it is important that DMA engine drivers drop any
137 	Note that callbacks will always be invoked from the DMA
143    added, it must be placed on the DMA engine drivers pending queue.
148    This returns a cookie can be used to check the progress of DMA engine
149    activity via other DMA engine calls not covered in this document.
151    dmaengine_submit() will not start the DMA operation, it merely adds
154 5. Issue pending DMA requests and wait for callback notification
160    On completion of each DMA operation, the next in queue is started and
171    This causes all activity for the DMA channel to be stopped, and may
172    discard data in the DMA FIFO which hasn't been fully transferred.
177    This pauses activity on the DMA channel without data loss.
181    Resume a previously paused DMA channel.  It is invalid to resume a
193    completion of a specific DMA transaction.
196 	Not all DMA engine drivers can return reliable information for
197 	a running DMA channel.  It is recommended that DMA engine users