Merge branch 'topic/doc' into for-linus
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@ -37,8 +37,8 @@ The slave DMA usage consists of following steps:
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2. Set slave and controller specific parameters
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Next step is always to pass some specific information to the DMA
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driver. Most of the generic information which a slave DMA can use
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is in struct dma_slave_config. This allows the clients to specify
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driver. Most of the generic information which a slave DMA can use
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is in struct dma_slave_config. This allows the clients to specify
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DMA direction, DMA addresses, bus widths, DMA burst lengths etc
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for the peripheral.
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@ -52,7 +52,7 @@ The slave DMA usage consists of following steps:
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struct dma_slave_config *config)
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Please see the dma_slave_config structure definition in dmaengine.h
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for a detailed explanation of the struct members. Please note
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for a detailed explanation of the struct members. Please note
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that the 'direction' member will be going away as it duplicates the
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direction given in the prepare call.
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@ -101,7 +101,7 @@ The slave DMA usage consists of following steps:
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desc = dmaengine_prep_slave_sg(chan, sgl, nr_sg, direction, flags);
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Once a descriptor has been obtained, the callback information can be
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added and the descriptor must then be submitted. Some DMA engine
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added and the descriptor must then be submitted. Some DMA engine
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drivers may hold a spinlock between a successful preparation and
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submission so it is important that these two operations are closely
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paired.
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@ -138,7 +138,7 @@ The slave DMA usage consists of following steps:
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activity via other DMA engine calls not covered in this document.
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dmaengine_submit() will not start the DMA operation, it merely adds
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it to the pending queue. For this, see step 5, dma_async_issue_pending.
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it to the pending queue. For this, see step 5, dma_async_issue_pending.
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5. Issue pending DMA requests and wait for callback notification
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@ -184,13 +184,13 @@ Further APIs:
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3. int dmaengine_resume(struct dma_chan *chan)
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Resume a previously paused DMA channel. It is invalid to resume a
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Resume a previously paused DMA channel. It is invalid to resume a
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channel which is not currently paused.
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4. enum dma_status dma_async_is_tx_complete(struct dma_chan *chan,
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dma_cookie_t cookie, dma_cookie_t *last, dma_cookie_t *used)
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This can be used to check the status of the channel. Please see
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This can be used to check the status of the channel. Please see
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the documentation in include/linux/dmaengine.h for a more complete
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description of this API.
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@ -200,7 +200,7 @@ Further APIs:
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Note:
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Not all DMA engine drivers can return reliable information for
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a running DMA channel. It is recommended that DMA engine users
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a running DMA channel. It is recommended that DMA engine users
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pause or stop (via dmaengine_terminate_all()) the channel before
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using this API.
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@ -34,7 +34,7 @@ command:
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% ls -1 /sys/class/dma/
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Once started a message like "dmatest: Started 1 threads using dma0chan0" is
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emitted. After that only test failure messages are reported until the test
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emitted. After that only test failure messages are reported until the test
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stops.
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Note that running a new test will not stop any in progress test.
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@ -43,11 +43,11 @@ The following command returns the state of the test.
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% cat /sys/module/dmatest/parameters/run
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To wait for test completion userpace can poll 'run' until it is false, or use
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the wait parameter. Specifying 'wait=1' when loading the module causes module
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the wait parameter. Specifying 'wait=1' when loading the module causes module
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initialization to pause until a test run has completed, while reading
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/sys/module/dmatest/parameters/wait waits for any running test to complete
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before returning. For example, the following scripts wait for 42 tests
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to complete before exiting. Note that if 'iterations' is set to 'infinite' then
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before returning. For example, the following scripts wait for 42 tests
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to complete before exiting. Note that if 'iterations' is set to 'infinite' then
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waiting is disabled.
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Example:
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@ -81,7 +81,7 @@ Example of output:
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The message format is unified across the different types of errors. A number in
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the parens represents additional information, e.g. error code, error counter,
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or status. A test thread also emits a summary line at completion listing the
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or status. A test thread also emits a summary line at completion listing the
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number of tests executed, number that failed, and a result code.
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Example:
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@ -384,7 +384,7 @@ where to put them)
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- The descriptor should be prepared for reuse by invoking
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dmaengine_desc_set_reuse() which will set DMA_CTRL_REUSE.
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- dmaengine_desc_set_reuse() will succeed only when channel support
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reusable descriptor as exhibited by capablities
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reusable descriptor as exhibited by capabilities
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- As a consequence, if a device driver wants to skip the dma_map_sg() and
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dma_unmap_sg() in between 2 transfers, because the DMA'd data wasn't used,
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it can resubmit the transfer right after its completion.
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@ -29,7 +29,7 @@ Constraints
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d) Bandwidth guarantee
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The PXA architecture has 4 levels of DMAs priorities : high, normal, low.
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The high prorities get twice as much bandwidth as the normal, which get twice
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The high priorities get twice as much bandwidth as the normal, which get twice
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as much as the low priorities.
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A driver should be able to request a priority, especially the real-time
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ones such as pxa_camera with (big) throughputs.
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