5b00f40f90
Based on a patch from Brent DeGraaf: "The datamover supports channels which can be shared amongst devices. As a result, the actual data transfer may occur some time after the request is queued up. Some devices such as mmc host controllers will timeout if a command is issued too far in advance of the actual transfer, so if dma to other devices on the same channel is already in progress or queued up, the added delay can cause pending transfers to fail before they start. This change extends the api to allow a user callback to be invoked just before the actual transfer takes place, thus allowing actions directly associated with the dma transfer, such as device commands, to be invoked with precise timing. Without this mechanism, there is no way for a driver to realize this timing. Also adds a user pointer to the command structure for use by the caller to reference information that may be needed by the callback routine for proper identification and processing associated with that specific request. This change is necessary to fix problems associated with excessive command timeouts and race conditions in the mmc driver." This patch also fixes all the callers of msm_dmov_enqueue_cmd() to ensure their callback function is NULL. Signed-off-by: San Mehat <san@google.com> Cc: Brent DeGraaf <bdegraaf@quicinc.com> Cc: Brian Swetland <swetland@google.com> Signed-off-by: Daniel Walker <dwalker@codeaurora.org> |
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