From mboxrd@z Thu Jan  1 00:00:00 1970
From: b32955@freescale.com (Huang Shijie)
Date: Wed, 23 Nov 2011 19:29:20 +0800
Subject: [PATCH] IMX/SDMA : save the real count for one DMA transaction.
In-Reply-To: <20111123111816.GF4063@pengutronix.de>
References: <1322039585-7901-1-git-send-email-b32955@freescale.com>
 <20111123105821.GC4063@pengutronix.de> <4ECCD34C.1090400@freescale.com>
 <20111123110626.GD4063@pengutronix.de> <4ECCD553.5020804@freescale.com>
 <20111123111816.GF4063@pengutronix.de>
Message-ID: <4ECCD910.1010004@freescale.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org


> 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;
-------------------------------------------------------

Best Regards
Huang Shijie