From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mail-bl2lp0206.outbound.protection.outlook.com
 ([207.46.163.206] helo=na01-bl2-obe.outbound.protection.outlook.com)
 by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux))
 id 1WdbgZ-0003qj-Ki
 for linux-mtd@lists.infradead.org; Fri, 25 Apr 2014 08:40:44 +0000
Date: Fri, 25 Apr 2014 15:43:13 +0800
From: Huang Shijie <b32955@freescale.com>
To: Kamal Dasu <kdasu.kdev@gmail.com>
Subject: Re: [PATCH v2] mtd: nand: Add support to use nand_base poi databuf
 as bounce buffer
Message-ID: <20140425074310.GA2117@localhost>
References: <1398375634-24759-1-git-send-email-kdasu.kdev@gmail.com>
 <5359C361.9000302@freescale.com>
 <CAC=U0a0OwJe4f4ZC6GBWzrVZ6fF1Lq=QB1E0ZBANww=k7L4cXA@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Disposition: inline
In-Reply-To: <CAC=U0a0OwJe4f4ZC6GBWzrVZ6fF1Lq=QB1E0ZBANww=k7L4cXA@mail.gmail.com>
Cc: linux-mtd@lists.infradead.org
List-Id: Linux MTD discussion mailing list <linux-mtd.lists.infradead.org>
List-Unsubscribe: <http://lists.infradead.org/mailman/options/linux-mtd>,
 <mailto:linux-mtd-request@lists.infradead.org?subject=unsubscribe>
List-Archive: <http://lists.infradead.org/pipermail/linux-mtd/>
List-Post: <mailto:linux-mtd@lists.infradead.org>
List-Help: <mailto:linux-mtd-request@lists.infradead.org?subject=help>
List-Subscribe: <http://lists.infradead.org/mailman/listinfo/linux-mtd>,
 <mailto:linux-mtd-request@lists.infradead.org?subject=subscribe>

On Thu, Apr 24, 2014 at 11:52:41PM -0400, Kamal Dasu wrote:
> Huang,
> 
> "could you show us how do the driver use the highmem buffer?"
> 
> This is the stack on a BMIPS platform we are doing a read dma transaction.
> drv_*  calls are from out of tree nand controller  driver. This
I can read the driver since it is not in the l2-mtd. :(

> example shows the driver trying to map
> highmem virtual address(0xfe1141e0)  for DMA operation passed from

Which dma api do you use?
do you use the dma_map_sg() or something else?

If you use the dma_map_sg, do it support the highmem in the MIPS?

thanks
Huang Shijie