[PATCH] mtd: nand: mxs: reset BCH earlier to avoid NAND startup problems

[Sascha Hauer]

On Wed, Dec 05, 2012 at 03:53:53PM +0100, Wolfram Sang wrote:
> It could happen (1 out of 100 times) that NAND did not start up
> correctly after warm rebooting, so barebox could not find its
> environment or DMA timed out due to a stalled BCH. When resetting BCH
> together with GPMI, the issue could not be observed anymore. We probably
> need the consistent state already before sending commands to NAND.

The subject suggests that the BCH engine is resetted earlier, but
instead of moving the reset this patch adds another reset. Is this
intended?

Sascha

> 
> Signed-off-by: Wolfram Sang <w.sang at pengutronix.de>
> ---
>  drivers/mtd/nand/nand_mxs.c |   13 ++++++++++---
>  1 file changed, 10 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mtd/nand/nand_mxs.c b/drivers/mtd/nand/nand_mxs.c
> index 975a44f..c4509d3 100644
> --- a/drivers/mtd/nand/nand_mxs.c
> +++ b/drivers/mtd/nand/nand_mxs.c
> @@ -1128,6 +1128,7 @@ int mxs_nand_alloc_buffers(struct mxs_nand_info *nand_info)
>  int mxs_nand_hw_init(struct mxs_nand_info *info)
>  {
>  	void __iomem *gpmi_regs = (void *)MXS_GPMI_BASE;
> +	void __iomem *bch_regs = (void __iomem *)MXS_BCH_BASE;
>  	int i = 0, ret;
>  	u32 val;
>  
> @@ -1153,6 +1154,15 @@ int mxs_nand_hw_init(struct mxs_nand_info *info)
>  	if (ret)
>  		return ret;
>  
> +	val = readl(gpmi_regs + GPMI_VERSION);
> +	info->version = val >> GPMI_VERSION_MINOR_OFFSET;
> +
> +	/* Reset BCH. Don't use SFTRST on MX23 due to Errata #2847 */
> +	ret = mxs_reset_block(bch_regs + BCH_CTRL,
> +				info->version == GPMI_VERSION_TYPE_MX23);
> +	if (ret)
> +		return ret;
> +
>  	/*
>  	 * Choose NAND mode, set IRQ polarity, disable write protection and
>  	 * select BCH ECC.
> @@ -1163,9 +1173,6 @@ int mxs_nand_hw_init(struct mxs_nand_info *info)
>  		GPMI_CTRL1_BCH_MODE;
>  	writel(val, gpmi_regs + GPMI_CTRL1);
>  
> -	val = readl(gpmi_regs + GPMI_VERSION);
> -	info->version = val >> GPMI_VERSION_MINOR_OFFSET;
> -
>  	return 0;
>  
>  err2:
> -- 
> 1.7.10.4
> 
> 
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> 

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