From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 23 Sep 2014 16:58:22 +0200 From: Boris BREZILLON To: Huang Shijie Subject: Re: [PATCH v3 1/3] mtd: nand: gpmi: add gpmi_move_bits function Message-ID: <20140923165822.27cfde69@bbrezillon> In-Reply-To: <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> <20140923145413.GA1633@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Mike Voytovich , linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, Roy Lee , Brian Norris , David Woodhouse , linux-arm-kernel@lists.infradead.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, 23 Sep 2014 22:54:15 +0800 Huang Shijie wrote: > 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 > > --- > > 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. Any suggestions ? > > We could use the bytes to replace the @nbits. > > The chunk data is always byte aligned. This function is also used to store ECC bits in the OOB buffer and these chunk of data are not byte aligned :-). > > > Btw: please add more comments in this function. Yep, I should definitely comment it, and I'll do. Best Regards, Boris -- Boris Brezillon, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com