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dmaengine: Add helper function to prep for error reporting 

Dmaengine does not provide a way to pass back the result from a DMA
transaction through the callback function. We are adding dmaengine
helper function in order to prep for a mechanism that allow result
status and other information through the callback. The initial conversion
will make the existing driver use these new helper functions but retain
the original behavior of the code. However, the helper functions paves
a way towards adding the result parameter through callback.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
hifive-unleashed-5.1
Dave Jiang 2016-07-20 13:10:31 -07:00 committed by Vinod Koul
parent 29b4817d40
commit f083f55718
1 changed files with 72 additions and 0 deletions
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72
drivers/dma/dmaengine.h
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@ -86,4 +86,76 @@ static inline void dma_set_residue(struct dma_tx_state *state, u32 residue)
state->residue = residue;
}
struct dmaengine_desc_callback {
dma_async_tx_callback callback;
void *callback_param;
};
/**
* dmaengine_desc_get_callback - get the passed in callback function
* @tx: tx descriptor
* @cb: temp struct to hold the callback info
*
* Fill the passed in cb struct with what's available in the passed in
* tx descriptor struct
* No locking is required.
*/
static inline void
dmaengine_desc_get_callback(struct dma_async_tx_descriptor *tx,
struct dmaengine_desc_callback *cb)
{
cb->callback = tx->callback;
cb->callback_param = tx->callback_param;
}
/**
* dmaengine_desc_callback_invoke - call the callback function in cb struct
* @cb: temp struct that is holding the callback info
* @result: dummy pointer for now
*
* Call the callback function provided in the cb struct with the parameter
* in the cb struct.
* Locking is dependent on the driver.
*/
static inline void
dmaengine_desc_callback_invoke(struct dmaengine_desc_callback *cb,
const void *result)
{
if (cb->callback)
cb->callback(cb->callback_param);
}
/**
* dmaengine_desc_get_callback_invoke - get the callback in tx descriptor and
* then immediately call the callback.
* @tx: dma async tx descriptor
* @result: dummy pointer for now
*
* Call dmaengine_desc_get_callback() and dmaengine_desc_callback_invoke()
* in a single function since no work is necessary in between for the driver.
* Locking is dependent on the driver.
*/
static inline void
dmaengine_desc_get_callback_invoke(struct dma_async_tx_descriptor *tx,
const void *result)
{
struct dmaengine_desc_callback cb;
dmaengine_desc_get_callback(tx, &cb);
dmaengine_desc_callback_invoke(&cb, result);
}
/**
* dmaengine_desc_callback_valid - verify the callback is valid in cb
* @cb: callback info struct
*
* Return a bool that verifies whether callback in cb is valid or not.
* No locking is required.
*/
static inline bool
dmaengine_desc_callback_valid(struct dmaengine_desc_callback *cb)
{
return (cb->callback) ? true : false;
}
#endif