Subject: [PATCH v2] MTD/GPMI bugfix : reset the BCH module when it is not MX23

From: [email-masked] (Marek Vasut)
Date: Fri, 30 Dec 2011 15:01:07 +0100

> In MX28, if we do not reset the BCH module. The BCH module may
> becomes unstable when the board reboots for several thousands times.
> This bug has been catched in customer's production.
> 
> The patch adds some comments, and fixes it now.
> 
> Also change gpmi_reset_block() to static.
> 
> Signed-off-by: Huang Shijie <[email-masked]>
> ---
>  drivers/mtd/nand/gpmi-nand/gpmi-lib.c |   10 +++++++---
>  1 files changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
> b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c index de4db76..1573e99 100644
> --- a/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
> +++ b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
> @@ -69,7 +69,8 @@ static int clear_poll_bit(void __iomem *addr, u32 mask)
>   *  [1] enable the module.
>   *  [2] reset the module.
>   *
> - * In most of the cases, it's ok. But there is a hardware bug in the BCH
> block. + * In most of the cases, it's ok.
> + * But in MX23, there is a hardware bug in the BCH block.
>   * If you try to soft reset the BCH block, it becomes unusable until
>   * the next hard reset. This case occurs in the NAND boot mode. When the
> board * boots by NAND, the ROM of the chip will initialize the BCH blocks
> itself. @@ -78,8 +79,10 @@ static int clear_poll_bit(void __iomem *addr,
> u32 mask) *
>   * To avoid this bug, just add a new parameter `just_enable` for
>   * the mxs_reset_block(), and rewrite it here.
> + *
> + * The bug has been fixed in the following chips, such as MX28.
>   */
> -int gpmi_reset_block(void __iomem *reset_addr, bool just_enable)
> +static int gpmi_reset_block(void __iomem *reset_addr, bool just_enable)
>  {
>  	int ret;
>  	int timeout = 0x400;
> @@ -206,7 +209,8 @@ int bch_set_geometry(struct gpmi_nand_data *this)
>  	if (ret)
>  		goto err_out;
> 
> -	ret = gpmi_reset_block(r->bch_regs, true);
> +	/* The bug only exits in mx23, the following chips fix it. */
> +	ret = gpmi_reset_block(r->bch_regs, GPMI_IS_MX23(this));
>  	if (ret)
>  		goto err_out;

Looks sane, though I can't test right now.

Acked-by: Marek Vasut <[email-masked]>