[PATCH] IMX/SDMA : save the real count for one DMA transaction.

[w.sang@pengutronix.de (Wolfram Sang)]

On Wed, Nov 23, 2011 at 07:29:20PM +0800, Huang Shijie wrote:
> 
> > On Wed, Nov 23, 2011 at 07:13:23PM +0800, Huang Shijie wrote:
> >>>>>> +	/* save the real count we received or transmitted. */
> >>>>>> +	chan->private = (void *)count;
> >>>>> And if someone later needs another variable which is private?
> >>>>>
> >>>> I ever wanted to add an new parameter `void *` to dma_aync_tx_callback,
> >>>> but it seemed i have
> >>>> to change a lot of files.
> >>>>
> >>>> Do you have any better suggestion?
> >>> Use a private struct and put count in there.
> >>>
> >> Where to put the private struct? in the imx-sdma.c ?
> >> If i put it there, how can i get it in the UART driver with the current
> >> DMA API?
> > So, in the UART driver you assume that void* is an int? Or how do you
> > currently use count?
> >
> In the UART driver, I use the following lines:
> -------------------------------------------------------
> + struct dma_chan *chan = sport->dma_chan_rx;
> + unsigned int count = (unsigned int)chan->private;
> -------------------------------------------------------

And why can't you use a struct here? chan->private->count?

Even then, I doubt if you can get this into mainline. But when you try,
please always post a user for this change (or a reference to it), that
is, the uart-driver. Otherwise there is no reason to include a change.

Regards,

   Wolfram


-- 
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
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