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

[Huang Shijie]

于 2011年11月23日 19:40, Vinod Koul 写道:
> On Wed, 2011-11-23 at 19:29 +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;
>> -------------------------------------------------------
> Chan->private is a depreciated field, and will be removed soon...
> possibly 3.3, so obviosly any usage of it is incorrect
>
> Why dont you use .device_tx_status callback and return the number of
> bytes remaining to be transmitted in residue value of the struct
> dma_tx_state. That should be size - count.
>
Thanks a lot.

Huang Shijie