linux-kernel - Re: [PATCH v2 7/7] mtd: spi-nor: Rework the disabling of block write protection

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Message-ID: <20190825142421.35d31a9b@collabora.com>
Date:   Sun, 25 Aug 2019 14:24:21 +0200
From:   Boris Brezillon <boris.brezillon@...labora.com>
To:     <Tudor.Ambarus@...rochip.com>
Cc:     <marek.vasut@...il.com>, <vigneshr@...com>,
        <miquel.raynal@...tlin.com>, <richard@....at>,
        <linux-mtd@...ts.infradead.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 7/7] mtd: spi-nor: Rework the disabling of block
 write protection

On Sat, 24 Aug 2019 12:00:48 +0000
<Tudor.Ambarus@...rochip.com> wrote:

> From: Tudor Ambarus <tudor.ambarus@...rochip.com>
> 
> Get rid of MFR handling and implement specific manufacturer
> default_init() fixup hooks.
> 
> Signed-off-by: Tudor Ambarus <tudor.ambarus@...rochip.com>
> ---
>  drivers/mtd/spi-nor/spi-nor.c | 30 ++++++++++++++++++++----------
>  1 file changed, 20 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> index fc9e14777212..f4e9fcca619f 100644
> --- a/drivers/mtd/spi-nor/spi-nor.c
> +++ b/drivers/mtd/spi-nor/spi-nor.c
> @@ -4146,6 +4146,16 @@ static int spi_nor_parse_sfdp(struct spi_nor *nor,
>  	return err;
>  }
>  
> +static void atmel_set_default_init(struct spi_nor *nor)
> +{
> +	nor->params.disable_block_protection = spi_nor_clear_sr_bp;
> +}
> +
> +static void intel_set_default_init(struct spi_nor *nor)
> +{
> +	nor->params.disable_block_protection = spi_nor_clear_sr_bp;

That's weird: you can unlock blocks but locking is not
explicitly flagged as supported (SNOR_F_HAS_LOCK is not set). Is that
expected?

> +}
> +
>  static void macronix_set_default_init(struct spi_nor *nor)
>  {
>  	nor->params.quad_enable = macronix_quad_enable;
> @@ -4173,6 +4183,14 @@ static void spi_nor_manufacturer_init_params(struct spi_nor *nor)
>  {
>  	/* Init flash parameters based on MFR */
>  	switch (JEDEC_MFR(nor->info)) {
> +	case SNOR_MFR_ATMEL:
> +		atmel_set_default_init(nor);
> +		break;
> +
> +	case SNOR_MFR_INTEL:
> +		intel_set_default_init(nor);
> +		break;
> +
>  	case SNOR_MFR_MACRONIX:
>  		macronix_set_default_init(nor);
>  		break;
> @@ -4760,18 +4778,10 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
>  	if (info->flags & SPI_S3AN)
>  		nor->flags |=  SNOR_F_READY_XSR_RDY;
>  
> -	if (info->flags & SPI_NOR_HAS_LOCK)
> +	if (info->flags & SPI_NOR_HAS_LOCK) {

If this flag implies SR_BP-based locking we should really rename it into
SPI_NOR_HAS_SR_BP_LOCK to avoid any confusion.

>  		nor->flags |= SNOR_F_HAS_LOCK;
> -
> -	/*
> -	 * Atmel, SST, Intel/Numonyx, and others serial NOR tend to power up
> -	 * with the software protection bits set.
> -	 */
> -	if (JEDEC_MFR(nor->info) == SNOR_MFR_ATMEL ||
> -	    JEDEC_MFR(nor->info) == SNOR_MFR_INTEL ||
> -	    JEDEC_MFR(nor->info) == SNOR_MFR_SST ||
> -	    nor->info->flags & SPI_NOR_HAS_LOCK)
>  		nor->params.disable_block_protection = spi_nor_clear_sr_bp;
> +	}
>  
>  	/* Init flash parameters based on flash_info struct and SFDP */
>  	spi_nor_init_params(nor);