From mboxrd@z Thu Jan  1 00:00:00 1970
Date: Tue, 23 Sep 2014 22:54:15 +0800
From: Huang Shijie <shijie8@gmail.com>
To: Boris BREZILLON <boris.brezillon@free-electrons.com>
Subject: Re: [PATCH v3 1/3] mtd: nand: gpmi: add gpmi_move_bits function
Message-ID: <20140923145413.GA1633@localhost.localdomain>
References: <1411481256-29141-1-git-send-email-boris.brezillon@free-electrons.com>
 <1411481256-29141-2-git-send-email-boris.brezillon@free-electrons.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <1411481256-29141-2-git-send-email-boris.brezillon@free-electrons.com>
Cc: Mike Voytovich <mvoytovich@paypal.com>, linux-kernel@vger.kernel.org,
 linux-mtd@lists.infradead.org, Roy Lee <roylee@paypal.com>,
 Brian Norris <computersforpeace@gmail.com>,
 David Woodhouse <dwmw2@infradead.org>, linux-arm-kernel@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 Tue, Sep 23, 2014 at 04:07:34PM +0200, Boris BREZILLON wrote:
> Add a new function to move bits (not bytes) from a memory region to
> another one.
> This function is similar to memmove except it acts at bit level.
> This function is needed to implement GPMI raw access functions, given the
> fact that ECC engine does not pad ECC bits to the next byte boundary.
sorry for not comment your v2 patch set.

> 
> Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
> ---
>  drivers/mtd/nand/gpmi-nand/gpmi-lib.c  | 88 ++++++++++++++++++++++++++++++++++
>  drivers/mtd/nand/gpmi-nand/gpmi-nand.h |  4 ++
>  2 files changed, 92 insertions(+)
> 
> diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-lib.c b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
> index 87e658c..e2f706a 100644
> --- a/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
> +++ b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
> @@ -1353,3 +1353,91 @@ int gpmi_read_page(struct gpmi_nand_data *this,
>  	set_dma_type(this, DMA_FOR_READ_ECC_PAGE);
>  	return start_dma_with_bch_irq(this, desc);
>  }
> +
> +void gpmi_move_bits(u8 *dst, size_t dst_bit_off,
> +		    const u8 *src, size_t src_bit_off,
> +		    size_t nbits)
we can simplify the code.

We could use the bytes to replace the @nbits.

The chunk data is always byte aligned.


Btw: please add more comments in this function.

thanks
Huang Shijie