Re: [PATCH 3/4] ARM: dts: da850-lcdk: Add NAND to DT

[Karl Beldan <kbeldan@baylibre.com>]

On Tue, Aug 09, 2016 at 05:15:17PM +0000, Karl Beldan wrote:
> This adds DT support for the NAND connected to the SoC AEMIF.
> The parameters (timings, ecc) are the same as what the board ships with
> (default AEMIF timings, 1bit ECC) and improvements will be handled in
> due course.
> This passed elementary tests hashing a 20MB file on top of ubifs on my
> LCDK.
> 
> Signed-off-by: Karl Beldan <kbeldan@baylibre.com>
> ---
>  arch/arm/boot/dts/da850-lcdk.dts | 108 +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 108 insertions(+)
> 
> diff --git a/arch/arm/boot/dts/da850-lcdk.dts b/arch/arm/boot/dts/da850-lcdk.dts
> index dbcca0b..033380b 100644
> --- a/arch/arm/boot/dts/da850-lcdk.dts
> +++ b/arch/arm/boot/dts/da850-lcdk.dts
> @@ -27,6 +27,27 @@
>  
>  &pmx_core {
>  	status = "okay";
> +
> +	nand_pins: nand_pins {
> +		pinctrl-single,bits = <
> +			/* EMA_WAIT[0], EMA_OE, EMA_WE, EMA_CS[3] */
> +			0x1c 0x10110010  0xf0ff00f0
> +			/*
> +			 * EMA_D[0], EMA_D[1], EMA_D[2],
> +			 * EMA_D[3], EMA_D[4], EMA_D[5],
> +			 * EMA_D[6], EMA_D[7]
> +			 */
> +			0x24 0x11111111  0xffffffff
> +			/*
> +			 * EMA_D[8],  EMA_D[9],  EMA_D[10],
> +			 * EMA_D[11], EMA_D[12], EMA_D[13],
> +			 * EMA_D[14], EMA_D[15]
> +			 */
> +			0x20 0x11111111  0xffffffff
> +			/* EMA_A[1], EMA_A[2] */
> +			0x30 0x01100000  0x0ff00000
> +		>;
> +	};
>  };
>  
>  &serial2 {
> @@ -68,3 +89,90 @@
>  	cd-gpios = <&gpio 64 GPIO_ACTIVE_HIGH>;
>  	status = "okay";
>  };
> +
> +&aemif {
> +	pinctrl-names = "default";
> +	pinctrl-0 = <&nand_pins>;
> +	status = "ok";
> +	cs2 {
Typo, should be cs3.
 
Karl
> +		#address-cells = <2>;
> +		#size-cells = <1>;
> +		clock-ranges;
> +		ranges;
> +
> +		ti,cs-chipselect = <2>;
> +
> +		nand@2000000,0 {
> +			compatible = "ti,davinci-nand";
> +			#address-cells = <1>;
> +			#size-cells = <1>;
> +			reg = <0 0x02000000 0x02000000
> +			       1 0x00000000 0x00008000>;
> +
> +			ti,davinci-chipselect = <1>;
> +			ti,davinci-mask-ale = <0>;
> +			ti,davinci-mask-cle = <0>;
> +			ti,davinci-mask-chipsel = <0>;
> +
> +			/*
> +			 * nand_ecc_strength_good will emit a warning
> +			 * but the LCDK ships with these settings [1].
> +			 * Also HW 4bits ECC with 16bits NAND seems to
> +			 * require some attention.
> +			 *
> +			 * ATM nand_davinci_probe handling of nand-ecc-*
> +			 * is broken, e.g.
> +			 * chip.ecc.strength = pdata->ecc_bits occurs after
> +			 * scan_ident(), otherwise I would have used:
> +			 * 	nand-ecc-mode = "hw";
> +			 * 	nand-ecc-strength = <1>;
> +			 * 	nand-ecc-step-size = <512>;
> +			 */
> +			ti,davinci-ecc-mode = "hw";
> +			ti,davinci-ecc-bits = <1>;
> +
> +			nand-bus-width= <16>;
> +			nand-on-flash-bbt;
> +
> +			/*
> +			 * LCDK original partitions:
> +			 * 0x000000000000-0x000000020000 : "u-boot env"
> +			 * 0x000000020000-0x0000000a0000 : "u-boot"
> +			 * 0x0000000a0000-0x0000002a0000 : "kernel"
> +			 * 0x0000002a0000-0x000020000000 : "filesystem"
> +			 *
> +			 * The 1st NAND block being guaranted to be valid w/o ECC (> 1k cycles),
> +			 * it makes a perfect candidate as an SPL for the BootROM to jump to.
> +			 * However the OMAP-L132/L138 Bootloader doc SPRAB41E reads:
> +			 * "To boot from NAND Flash, the AIS should be written to NAND block 1
> +			 * (NAND block 0 is not used by default)", which matches the LCDK
> +			 * original partitioning.
> +			 * Also, the LCDK ships with only the u-boot partition provisioned and
> +			 * boots on it in its default configuration while using the MMC for the
> +			 * kernel and rootfs, so preserve that one as is for now.
> +			 * [1]: Ensuring for example that U-Boot LCDK SPL can handle it properly
> +			 * and a proper boot chain ROM->SPL->U-Boot->Linux wrt ECC, would allow
> +			 * for a better partitioning.
> +			 */
> +			partitions {
> +				compatible = "fixed-partitions";
> +				#address-cells = <1>;
> +				#size-cells = <1>;
> +
> +				partition@0 {
> +					label = "u-boot env";
> +					reg = <0 0x020000>;
> +				};
> +				partition@0x020000 {
> +					/* The LCDK defaults to booting from this partition */
> +					label = "u-boot";
> +					reg = <0x020000 0x080000>;
> +				};
> +				partition@0x0a0000 {
> +					label = "space";
> +					reg = <0x0a0000 0>;
> +				};
> +			};
> +		};
> +	};
> +};
> -- 
> 2.9.2
>