From: Huang Shijie Date: Thu, 7 Nov 2013 10:07:38 +0000 (+0800) Subject: mtd: gpmi: add a new DT property to use the datasheet's minimum required ECC X-Git-Tag: next-20131128~37^2~43 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=cfc8296e46c3f6a57b69b3e602f4efd66d973e39;p=karo-tx-linux.git mtd: gpmi: add a new DT property to use the datasheet's minimum required ECC In default way, we use the ecc_strength/ecc_step size calculated by ourselves 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 required 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 Micron's SLC NAND. If we fail to use the minimum ECC, we will use the legacy method to calculate the ecc_strength and ecc_step size. Signed-off-by: Huang Shijie Signed-off-by: Brian Norris --- diff --git a/Documentation/devicetree/bindings/mtd/gpmi-nand.txt b/Documentation/devicetree/bindings/mtd/gpmi-nand.txt index 551b2a179d01..458d59634688 100644 --- a/Documentation/devicetree/bindings/mtd/gpmi-nand.txt +++ b/Documentation/devicetree/bindings/mtd/gpmi-nand.txt @@ -17,6 +17,14 @@ Required properties: Optional properties: - nand-on-flash-bbt: boolean to enable on flash bbt option if not present false + - fsl,use-minimum-ecc: Protect this NAND flash with the minimum ECC + strength required. The required ECC strength is + automatically discoverable for some flash + (e.g., according to the ONFI standard). + However, note that if this strength is not + discoverable or this property is not enabled, + the software may chooses an implementation-defined + ECC scheme. 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 dabbc14db563..9c5911616a07 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_data *this) 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); }