Message-ID: <4642D095.6070305@cdac.in>
Date: Thu, 10 May 2007 13:28:13 +0530
From: Mahesh <maheshk@cdac.in>
User-Agent: Thunderbird 1.5.0.4 (Windows/20060516)
MIME-Version: 1.0
To: linux-kernel@vger.kernel.org
CC: kernelnewbies@nl.linux.org
Subject: [HOWTO] accessing the DMA mapped data
Content-Type: text/plain;
	charset=ISO-8859-1;
	format=flowed
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 921
Lines: 24

Hi list,

I have a small question regarding the accessing the data in the DMA 
mapped  region (in the driver).  In my driver I only have the 
'dma_addr_t addr' variable which is result after the 'dma_map_single'. 
I don't have access to the virtual address of the data region.

Is there helper routine which we will give me the virtual address back 
from the DMA mapped address???

After some searching in the net about it found 'dma_sync_single' which 
will help to synchronize it after 'modifying' the contents of the DMA mapped 
region. But to 'modify' the contents of DMA mapped region I require the virtual 
address, which is not available in my case.

Regards,
Mahesh.


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/