Re: [PATCH v4 4/8] mtd: nand: atmel: Avoid ECC errors when leaving backup mode

[Boris Brezillon <boris.brezillon@free-electrons.com>]

On Thu, 28 Sep 2017 11:46:23 +0200
Romain Izard <romain.izard.pro@gmail.com> wrote:

> During backup mode, the contents of all registers will be cleared as the
> SoC will be completely powered down. For a product that boots on NAND
> Flash memory, the bootloader will obviously use the related controller
> to read the Flash and correct any detected error in the memory, before
> handling back control to the kernel's resuming entry point.
> 
> But it does not clean the NAND controller registers after use and on its
> side the kernel driver expects the error locator to be powered down and
> in a clean state. Add a resume hook for the PMECC error locator, and
> reset its registers.
> 
> Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>

Applied.

Thanks,

Boris

> ---
> Changes in v3:
> * keep the PMECC disabled when not in use, and use atmel_pmecc_resume to
>   reset the controller after the bootloader has left it enabled.
> 
> Changes in v4:
> * export atmel_pmecc_reset instead of atmel_pmecc_resume
> * use the correct pointer in atmel_nand_controller_resume
> 
>  drivers/mtd/nand/atmel/nand-controller.c |  3 +++
>  drivers/mtd/nand/atmel/pmecc.c           | 17 +++++++++--------
>  drivers/mtd/nand/atmel/pmecc.h           |  1 +
>  3 files changed, 13 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/mtd/nand/atmel/nand-controller.c b/drivers/mtd/nand/atmel/nand-controller.c
> index f25eca79f4e5..8afcff9a66ea 100644
> --- a/drivers/mtd/nand/atmel/nand-controller.c
> +++ b/drivers/mtd/nand/atmel/nand-controller.c
> @@ -2530,6 +2530,9 @@ static __maybe_unused int atmel_nand_controller_resume(struct device *dev)
>  	struct atmel_nand_controller *nc = dev_get_drvdata(dev);
>  	struct atmel_nand *nand;
>  
> +	if (nc->pmecc)
> +		atmel_pmecc_reset(nc->pmecc);
> +
>  	list_for_each_entry(nand, &nc->chips, node) {
>  		int i;
>  
> diff --git a/drivers/mtd/nand/atmel/pmecc.c b/drivers/mtd/nand/atmel/pmecc.c
> index 146af8218314..0a3f12141c45 100644
> --- a/drivers/mtd/nand/atmel/pmecc.c
> +++ b/drivers/mtd/nand/atmel/pmecc.c
> @@ -765,6 +765,13 @@ void atmel_pmecc_get_generated_eccbytes(struct atmel_pmecc_user *user,
>  }
>  EXPORT_SYMBOL_GPL(atmel_pmecc_get_generated_eccbytes);
>  
> +void atmel_pmecc_reset(struct atmel_pmecc *pmecc)
> +{
> +	writel(PMECC_CTRL_RST, pmecc->regs.base + ATMEL_PMECC_CTRL);
> +	writel(PMECC_CTRL_DISABLE, pmecc->regs.base + ATMEL_PMECC_CTRL);
> +}
> +EXPORT_SYMBOL_GPL(atmel_pmecc_reset);
> +
>  int atmel_pmecc_enable(struct atmel_pmecc_user *user, int op)
>  {
>  	struct atmel_pmecc *pmecc = user->pmecc;
> @@ -797,10 +804,7 @@ EXPORT_SYMBOL_GPL(atmel_pmecc_enable);
>  
>  void atmel_pmecc_disable(struct atmel_pmecc_user *user)
>  {
> -	struct atmel_pmecc *pmecc = user->pmecc;
> -
> -	writel(PMECC_CTRL_RST, pmecc->regs.base + ATMEL_PMECC_CTRL);
> -	writel(PMECC_CTRL_DISABLE, pmecc->regs.base + ATMEL_PMECC_CTRL);
> +	atmel_pmecc_reset(user->pmecc);
>  	mutex_unlock(&user->pmecc->lock);
>  }
>  EXPORT_SYMBOL_GPL(atmel_pmecc_disable);
> @@ -855,10 +859,7 @@ static struct atmel_pmecc *atmel_pmecc_create(struct platform_device *pdev,
>  
>  	/* Disable all interrupts before registering the PMECC handler. */
>  	writel(0xffffffff, pmecc->regs.base + ATMEL_PMECC_IDR);
> -
> -	/* Reset the ECC engine */
> -	writel(PMECC_CTRL_RST, pmecc->regs.base + ATMEL_PMECC_CTRL);
> -	writel(PMECC_CTRL_DISABLE, pmecc->regs.base + ATMEL_PMECC_CTRL);
> +	atmel_pmecc_reset(pmecc);
>  
>  	return pmecc;
>  }
> diff --git a/drivers/mtd/nand/atmel/pmecc.h b/drivers/mtd/nand/atmel/pmecc.h
> index a8ddbfca2ea5..817e0dd9fd15 100644
> --- a/drivers/mtd/nand/atmel/pmecc.h
> +++ b/drivers/mtd/nand/atmel/pmecc.h
> @@ -61,6 +61,7 @@ atmel_pmecc_create_user(struct atmel_pmecc *pmecc,
>  			struct atmel_pmecc_user_req *req);
>  void atmel_pmecc_destroy_user(struct atmel_pmecc_user *user);
>  
> +void atmel_pmecc_reset(struct atmel_pmecc *pmecc);
>  int atmel_pmecc_enable(struct atmel_pmecc_user *user, int op);
>  void atmel_pmecc_disable(struct atmel_pmecc_user *user);
>  int atmel_pmecc_wait_rdy(struct atmel_pmecc_user *user);