Re: [PATCH] mtd: spi-nor: wait until lock/unlock operations are ready

[Brian Norris <computersforpeace@gmail.com>]

On Sun, Nov 22, 2015 at 10:09:57PM -0300, Ezequiel Garcia wrote:
> On Micron and Numonyx devices, the status register write command
> (WRSR), raises a work-in-progress bit (WIP) on the status register.
> The datasheets for these devices specify that while the status
> register write is in progress, the status register WIP bit can still
> be read to check the end of the operation.
> 
> This commit adds a wait_till_ready call on lock/unlock operations,
> only for these manufacturers. This is needed to prevent applications
> from issuing erase or program operations before the unlock operation
> is completed.
> 
> Reported-by: Stas Sergeev <stsp@list.ru>
> Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
> ---
>  drivers/mtd/spi-nor/spi-nor.c | 18 ++++++++++++++++--
>  1 file changed, 16 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> index e9c26c0e2258..acc9b05e02be 100644
> --- a/drivers/mtd/spi-nor/spi-nor.c
> +++ b/drivers/mtd/spi-nor/spi-nor.c
> @@ -485,6 +485,7 @@ static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
>  	u8 status_old, status_new;
>  	u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
>  	u8 shift = ffs(mask) - 1, pow, val;
> +	int ret;

I've merged other patches in the meantime (sorry), so this might need a
rebasing on l2-mtd.git. I'd do it, but should get a v2 anyway.

>  
>  	status_old = read_sr(nor);
>  
> @@ -521,7 +522,13 @@ static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
>  		return -EINVAL;
>  
>  	write_enable(nor);
> -	return write_sr(nor, status_new);
> +	ret = write_sr(nor, status_new);
> +	if (ret)
> +		return ret;
> +	ret = spi_nor_wait_till_ready(nor);
> +	if (ret)
> +		return ret;
> +	return 0;

Why not just return spi_nor_wait_till_ready(nor)?

>  }
>  
>  /*
> @@ -535,6 +542,7 @@ static int stm_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
>  	uint8_t status_old, status_new;
>  	u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
>  	u8 shift = ffs(mask) - 1, pow, val;
> +	int ret;
>  
>  	status_old = read_sr(nor);
>  
> @@ -569,7 +577,13 @@ static int stm_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
>  		return -EINVAL;
>  
>  	write_enable(nor);
> -	return write_sr(nor, status_new);
> +	ret = write_sr(nor, status_new);
> +	if (ret)
> +		return ret;
> +	ret = spi_nor_wait_till_ready(nor);
> +	if (ret)
> +		return ret;
> +	return 0;

Same?

>  }
>  
>  /*

Brian