From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from co9ehsobe003.messaging.microsoft.com ([207.46.163.26] helo=co9outboundpool.messaging.microsoft.com) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1VdZwk-0008Ju-Jz for linux-mtd@lists.infradead.org; Tue, 05 Nov 2013 06:17:03 +0000 Message-ID: <52788E05.6070907@freescale.com> Date: Tue, 5 Nov 2013 14:19:49 +0800 From: Huang Shijie MIME-Version: 1.0 To: Huang Shijie Subject: Re: [PATCH v2] mtd: gpmi: add a new DT property to use the datasheet's minimum required ECC References: <1382929517-22606-1-git-send-email-b32955@freescale.com> In-Reply-To: <1382929517-22606-1-git-send-email-b32955@freescale.com> Content-Type: text/plain; charset="GB2312" Content-Transfer-Encoding: quoted-printable Cc: linux-mtd@lists.infradead.org, devicetree@vger.kernel.org, computersforpeace@gmail.com, dwmw2@infradead.org, dedekind1@gmail.com List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , =D3=DA 2013=C4=EA10=D4=C228=C8=D5 11:05, Huang Shijie =D0=B4=B5=C0: > In default way, we use the ecc_strength/ecc_step size calculated by our= selves > and use all the OOB area. > > This patch adds a new property : "fsl,use-minimum-ecc" > > If we enable it, we will firstly try to use the datasheet's minimum req= uired > ECC provided by the MTD layer (the ecc_strength_ds/ecc_step_ds fields > in the nand_chip{}). So we may have free space in the OOB area by using= the > minimum ECC, and we may support JFFS2 with some SLC NANDs, such as Micr= on's > SLC NAND. > > If we fail to use the minimum ECC, we will use the legacy method to cal= culate > the ecc_strength and ecc_step size. > > Signed-off-by: Huang Shijie > --- > v1 --> v2: > based on David's patch to fix the regression. > --- > .../devicetree/bindings/mtd/gpmi-nand.txt | 6 ++++++ > drivers/mtd/nand/gpmi-nand/gpmi-nand.c | 3 +++ > 2 files changed, 9 insertions(+), 0 deletions(-) > > diff --git a/Documentation/devicetree/bindings/mtd/gpmi-nand.txt b/Docu= mentation/devicetree/bindings/mtd/gpmi-nand.txt > index 551b2a1..4297795 100644 > --- a/Documentation/devicetree/bindings/mtd/gpmi-nand.txt > +++ b/Documentation/devicetree/bindings/mtd/gpmi-nand.txt > @@ -17,6 +17,12 @@ Required properties: > Optional properties: > - nand-on-flash-bbt: boolean to enable on flash bbt option if not > present false > + - fsl,use-minimum-ecc: By enabling this boolean property, the gpmi w= ill try > + to use the datasheet's minimum required ECC pro= vided by > + the MTD layer (the ecc_strength_ds/ecc_step_ds = fields > + in the nand_chip{}). So we may have free space = in the OOB > + area by using the minimum ECC, and we may suppo= rt JFFS2 > + with some SLC NANDs, such as Micron's SLC NAND. > =20 > The device tree may optionally contain sub-nodes describing partitions= of the > address space. See partition.txt for more detail. > diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c b/drivers/mtd/nand/= gpmi-nand/gpmi-nand.c > index 7ac2280..3ec55d0 100644 > --- a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c > +++ b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c > @@ -352,6 +352,9 @@ static int legacy_set_geometry(struct gpmi_nand_dat= a *this) > =20 > int common_nfc_set_geometry(struct gpmi_nand_data *this) > { > + if (of_property_read_bool(this->dev->of_node, "fsl,use-minimum-ecc") > + && set_geometry_by_ecc_info(this)) > + return 0; > return legacy_set_geometry(this); > } > =20 any comment about this patch? thanks Huang Shijie