[U-Boot] [PATCH v2 3/5] at91: atmel_nand: Update driver to support Programmable Multibit ECC controller

[Scott Wood <scottwood@freescale.com>]

On 08/16/2012 12:05 AM, Josh Wu wrote:
> The Programmable Multibit ECC (PMECC) controller is a programmable binary
> BCH(Bose, Chaudhuri and Hocquenghem) encoder and decoder. This controller
> can be used to support both SLC and MLC NAND Flash devices. It supports to
> generate ECC to correct 2, 4, 8, 12 or 24 bits of error per sector of data.
> 
> To use PMECC in this driver, the user needs to set the PMECC correction
> capability, the sector size and ROM lookup table offsets in board config file.
> 
> This driver is ported from Linux kernel atmel_nand PMECC patch. The main difference
> is in this version it uses registers structure access hardware instead of using macros.

Sigh, I wish U-Boot's code style policies weren't so rigid as to force
such a difference relative to the Linux driver.

> +	/* Computation 2t syndromes based on S(x) */
> +	/* Odd syndromes */
> +	for (i = 1; i < 2 * cap; i += 2) {
> +		for (j = 0; j < host->pmecc_degree; j++) {
> +			if (partial_syn[i] & ((unsigned short)0x1 << j))
> +				si[i] = readw(alpha_to + i * j) ^ si[i];
> +		}

Will that (unsigned short) make any difference?  Won't it just get
promoted back to int for the computation?

> +		i++;
> +		err_nbr--;
> +	}
> +
> +	return;
> +}

If it came over from Linux this way, I'm not asking you to change it
just here, but the return; at the end is superfluous.

> +	while ((pmecc_readl(host->pmecc, sr) & PMECC_SR_BUSY))
> +		udelay(1);

Timeout?

-Scott