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linux-next/Documentation/devicetree/bindings/mtd/gpmi-nand.txt
Huang Shijie 89b59e6cc1 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 <b32955@freescale.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
2014-01-03 11:22:08 -08:00

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* Freescale General-Purpose Media Interface (GPMI)
The GPMI nand controller provides an interface to control the
NAND flash chips. We support only one NAND chip now.
Required properties:
- compatible : should be "fsl,<chip>-gpmi-nand"
- reg : should contain registers location and length for gpmi and bch.
- reg-names: Should contain the reg names "gpmi-nand" and "bch"
- interrupts : BCH interrupt number.
- interrupt-names : Should be "bch".
- dmas: DMA specifier, consisting of a phandle to DMA controller node
and GPMI DMA channel ID.
Refer to dma.txt and fsl-mxs-dma.txt for details.
- dma-names: Must be "rx-tx".
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.
Examples:
gpmi-nand@8000c000 {
compatible = "fsl,imx28-gpmi-nand";
#address-cells = <1>;
#size-cells = <1>;
reg = <0x8000c000 2000>, <0x8000a000 2000>;
reg-names = "gpmi-nand", "bch";
interrupts = <41>;
interrupt-names = "bch";
dmas = <&dma_apbh 4>;
dma-names = "rx-tx";
partition@0 {
...
};
};