On Thu, Oct 18, 2012 at 02:45:41PM +0800, Huang Shijie wrote:yes. it's a little better.ä 2012å10æ18æ 14:18, Vinod Koul åé:And what if you stop using clk_prepare_enable(), and prepare the clockWhy cant you do start (prepare clock etc) when you submit the descriptorI ever thought this method too.
to dmaengine. Can be done in tx_submit callback.
Similarly remove the clock when dma transaction gets completed.
But it will become low efficient in the following case:
Assuming the gpmi-nand driver has to read out 1024 pages in one
_SINGLE_ read operation.
The gpmi-nand will submit the descriptor to dmaengine per page. So with
the system will repeat the enable/disable dma clock 1024 time. At every
enable/disable dma clock,
the system has to enable the clock chain and it's parents ...
when the channel is requested and only use clk_enable() in the tx_submit