From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Brezillon Subject: Re: [PATCH v4 1/2] mtd: nand: fix generating over-boundary ECC data when writing Date: Wed, 31 Aug 2016 10:09:11 +0200 Message-ID: <20160831100911.2926b969@bbrezillon> References: <1472560548-30567-1-git-send-email-rogercc.lin@mediatek.com> <1472560548-30567-2-git-send-email-rogercc.lin@mediatek.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1472560548-30567-2-git-send-email-rogercc.lin-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+glpam-linux-mediatek=m.gmane.org-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org To: RogerCC Lin Cc: robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, daniel.thompson-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, steven.liu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org, srv_heupstream-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org, linux-mediatek-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-mtd-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, matthias.bgg-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, jorge.ramirez-ortiz-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, xiaolei.li-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org, computersforpeace-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org, blogic-p3rKhJxN3npAfugRpC6u6w@public.gmane.org List-Id: linux-mediatek@lists.infradead.org On Tue, 30 Aug 2016 20:35:47 +0800 RogerCC Lin wrote: > From: RogerCC Lin > > When mtk_ecc_encode() is writing the ECC parity data to the OOB > region,because each register is 4 bytes in length,but the len's unit is > in bytes,the operation in the for loop will cross the ECC's boundary. > > Signed-off-by: RogerCC Lin > --- > drivers/mtd/nand/mtk_ecc.c | 12 ++++++++---- > 1 files changed, 8 insertions(+), 4 deletions(-) > > diff --git a/drivers/mtd/nand/mtk_ecc.c b/drivers/mtd/nand/mtk_ecc.c > index 25a4fbd..495538e 100644 > --- a/drivers/mtd/nand/mtk_ecc.c > +++ b/drivers/mtd/nand/mtk_ecc.c > @@ -366,7 +366,8 @@ int mtk_ecc_encode(struct mtk_ecc *ecc, struct mtk_ecc_config *config, > u8 *data, u32 bytes) > { > dma_addr_t addr; > - u32 *p, len, i; > + u8 *p; > + u32 len, i, val; > int ret = 0; > > addr = dma_map_single(ecc->dev, data, bytes, DMA_TO_DEVICE); > @@ -392,11 +393,14 @@ int mtk_ecc_encode(struct mtk_ecc *ecc, struct mtk_ecc_config *config, > > /* Program ECC bytes to OOB: per sector oob = FDM + ECC + SPARE */ > len = (config->strength * ECC_PARITY_BITS + 7) >> 3; > - p = (u32 *)(data + bytes); > + p = data + bytes; > > /* write the parity bytes generated by the ECC back to the OOB region */ > - for (i = 0; i < len; i++) > - p[i] = readl(ecc->regs + ECC_ENCPAR(i)); > + for (i = 0; i < len; i++) { > + if ((i % 4) == 0) > + val = readl(ecc->regs + ECC_ENCPAR(i >> 2)); I'm nitpicking, but I'd prefer to have 'i / 4' instead of 'i >> 2' to be consistent with the 'i % 4' operation, and I also find it clearer. If you agree, I can do this change while applying the patch, no need to resend. > + p[i] = (val >> ((i % 4) * 8)) & 0xff; > + } > timeout: > > dma_unmap_single(ecc->dev, addr, bytes, DMA_TO_DEVICE);