Re: [PATCH v12 1/2] MTD: at91: add dt parameters for Atmel PMECC

[Nicolas Ferre <nicolas.ferre@atmel.com>]

On 06/28/2012 10:21 AM, Josh Wu :
> Add DT support for PMECC parameters.
> 
> Signed-off-by: Josh Wu <josh.wu@atmel.com>

Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>

> ---
> changes:
> since v11
>    1. update the documentation for reg parameter
>    2. add one example for PMECC support.
> 
>  .../devicetree/bindings/mtd/atmel-nand.txt         |   40 ++++++++++++++-
>  drivers/mtd/nand/atmel_nand.c                      |   52 +++++++++++++++++++-
>  2 files changed, 90 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/mtd/atmel-nand.txt b/Documentation/devicetree/bindings/mtd/atmel-nand.txt
> index a200695..d555421 100644
> --- a/Documentation/devicetree/bindings/mtd/atmel-nand.txt
> +++ b/Documentation/devicetree/bindings/mtd/atmel-nand.txt
> @@ -3,7 +3,9 @@ Atmel NAND flash
>  Required properties:
>  - compatible : "atmel,at91rm9200-nand".
>  - reg : should specify localbus address and size used for the chip,
> -	and if availlable the ECC.
> +	and hardware ECC controller if available.
> +	If the hardware ECC is PMECC, it should contain address and size for
> +	PMECC, PMECC Error Location controller and ROM which has lookup tables.
>  - atmel,nand-addr-offset : offset for the address latch.
>  - atmel,nand-cmd-offset : offset for the command latch.
>  - #address-cells, #size-cells : Must be present if the device has sub-nodes
> @@ -16,6 +18,15 @@ Optional properties:
>  - nand-ecc-mode : String, operation mode of the NAND ecc mode, soft by default.
>    Supported values are: "none", "soft", "hw", "hw_syndrome", "hw_oob_first",
>    "soft_bch".
> +- atmel,has-pmecc : boolean to enable Programmable Multibit ECC hardware.
> +  Only supported by at91sam9x5 or later sam9 product.
> +- atmel,pmecc-cap : error correct capability for Programmable Multibit ECC
> +  Controller. Supported values are: 2, 4, 8, 12, 24.
> +- atmel,pmecc-sector-size : sector size for ECC computation. Supported values
> +  are: 512, 1024.
> +- atmel,pmecc-lookup-table-offset : includes two offsets of lookup table in ROM
> +  for different sector size. First one is for sector size 512, the next is for
> +  sector size 1024.
>  - nand-bus-width : 8 or 16 bus width if not present 8
>  - nand-on-flash-bbt: boolean to enable on flash bbt option if not present false
>  
> @@ -39,3 +50,30 @@ nand0: nand@40000000,0 {
>  		...
>  	};
>  };
> +
> +/* for PMECC supported chips */
> +nand0: nand@40000000 {
> +	compatible = "atmel,at91rm9200-nand";
> +	#address-cells = <1>;
> +	#size-cells = <1>;
> +	reg = < 0x40000000 0x10000000	/* bus addr & size */
> +		0xffffe000 0x00000600	/* PMECC addr & size */
> +		0xffffe600 0x00000200	/* PMECC ERRLOC addr & size */
> +		0x00100000 0x00100000	/* ROM addr & size */
> +		>;
> +	atmel,nand-addr-offset = <21>;	/* ale */
> +	atmel,nand-cmd-offset = <22>;	/* cle */
> +	nand-on-flash-bbt;
> +	nand-ecc-mode = "hw";
> +	atmel,has-pmecc;	/* enable PMECC */
> +	atmel,pmecc-cap = <2>;
> +	atmel,pmecc-sector-size = <512>;
> +	atmel,pmecc-lookup-table-offset = <0x8000 0x10000>;
> +	gpios = <&pioD 5 0	/* rdy */
> +		 &pioD 4 0	/* nce */
> +		 0		/* cd */
> +		>;
> +	partition@0 {
> +		...
> +	};
> +};
> diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c
> index 7a41a04..b97ad9f 100644
> --- a/drivers/mtd/nand/atmel_nand.c
> +++ b/drivers/mtd/nand/atmel_nand.c
> @@ -93,6 +93,11 @@ struct atmel_nand_host {
>  
>  	struct completion	comp;
>  	struct dma_chan		*dma_chan;
> +
> +	bool			has_pmecc;
> +	u8			pmecc_corr_cap;
> +	u16			pmecc_sector_size;
> +	u32			pmecc_lookup_table_offset;
>  };
>  
>  static int cpu_has_dma(void)
> @@ -481,7 +486,8 @@ static void atmel_nand_hwctl(struct mtd_info *mtd, int mode)
>  static int __devinit atmel_of_init_port(struct atmel_nand_host *host,
>  					 struct device_node *np)
>  {
> -	u32 val;
> +	u32 val, table_offset;
> +	u32 offset[2];
>  	int ecc_mode;
>  	struct atmel_nand_data *board = &host->board;
>  	enum of_gpio_flags flags;
> @@ -517,6 +523,50 @@ static int __devinit atmel_of_init_port(struct atmel_nand_host *host,
>  	board->enable_pin = of_get_gpio(np, 1);
>  	board->det_pin = of_get_gpio(np, 2);
>  
> +	host->has_pmecc = of_property_read_bool(np, "atmel,has-pmecc");
> +
> +	if (!(board->ecc_mode == NAND_ECC_HW) || !host->has_pmecc)
> +		return 0;	/* Not using PMECC */
> +
> +	/* use PMECC, get correction capability, sector size and lookup
> +	 * table offset.
> +	 */
> +	if (of_property_read_u32(np, "atmel,pmecc-cap", &val) != 0) {
> +		dev_err(host->dev, "Cannot decide PMECC Capability\n");
> +		return -EINVAL;
> +	} else if ((val != 2) && (val != 4) && (val != 8) && (val != 12) &&
> +	    (val != 24)) {
> +		dev_err(host->dev,
> +			"Unsupported PMECC correction capability: %d; should be 2, 4, 8, 12 or 24\n",
> +			val);
> +		return -EINVAL;
> +	}
> +	host->pmecc_corr_cap = (u8)val;
> +
> +	if (of_property_read_u32(np, "atmel,pmecc-sector-size", &val) != 0) {
> +		dev_err(host->dev, "Cannot decide PMECC Sector Size\n");
> +		return -EINVAL;
> +	} else if ((val != 512) && (val != 1024)) {
> +		dev_err(host->dev,
> +			"Unsupported PMECC sector size: %d; should be 512 or 1024 bytes\n",
> +			val);
> +		return -EINVAL;
> +	}
> +	host->pmecc_sector_size = (u16)val;
> +
> +	if (of_property_read_u32_array(np, "atmel,pmecc-lookup-table-offset",
> +			offset, 2) != 0) {
> +		dev_err(host->dev, "Cannot get PMECC lookup table offset\n");
> +		return -EINVAL;
> +	}
> +	table_offset = host->pmecc_sector_size == 512 ? offset[0] : offset[1];
> +
> +	if (!table_offset) {
> +		dev_err(host->dev, "Invalid PMECC lookup table offset\n");
> +		return -EINVAL;
> +	}
> +	host->pmecc_lookup_table_offset = table_offset;
> +
>  	return 0;
>  }
>  #else
> 


-- 
Nicolas Ferre