linux-kernel - Re: [PATCH 2/2] mtd: spi-nor: sst: Add support for Global Unlock on sst26vf

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Message-ID: <20210120122940.2xkiwghtszzyylnm@ti.com>
Date:   Wed, 20 Jan 2021 17:59:40 +0530
From:   Pratyush Yadav <p.yadav@...com>
To:     Tudor Ambarus <tudor.ambarus@...rochip.com>
CC:     <michael@...le.cc>, <vigneshr@...com>, <richard@....at>,
        <linux-kernel@...r.kernel.org>, <linux-mtd@...ts.infradead.org>,
        <Kavyasree.Kotagiri@...rochip.com>, <miquel.raynal@...tlin.com>
Subject: Re: [PATCH 2/2] mtd: spi-nor: sst: Add support for Global Unlock on
 sst26vf

Hi Tudor,

On 20/01/21 12:54PM, Tudor Ambarus wrote:
> Even if sst26vf shares the SPINOR_OP_GBULK opcode with
> Macronix (ex. MX25U12835F) and Winbound (ex. W25Q128FV),
> it has its own Individual Block Protection scheme, which
> is also capable to read-lock individual parameter blocks.
> Thus the sst26vf's Individual Block Protection scheme will
> reside in the sst.c manufacturer driver.
> 
> Add support to unlock the entire flash memory. The device
> is write-protected by default after a power-on reset cycle
> (volatile software protection), in order to avoid inadvertent
> writes during power-up. Could do an erase, write, read back,
> and compare when MTD_SPI_NOR_SWP_DISABLE_ON_VOLATILE=y.
> 
> Signed-off-by: Tudor Ambarus <tudor.ambarus@...rochip.com>
> ---
>  drivers/mtd/spi-nor/sst.c | 38 ++++++++++++++++++++++++++++++++++++--
>  1 file changed, 36 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mtd/spi-nor/sst.c b/drivers/mtd/spi-nor/sst.c
> index 00e48da0744a..1cd2a360c41e 100644
> --- a/drivers/mtd/spi-nor/sst.c
> +++ b/drivers/mtd/spi-nor/sst.c
> @@ -8,6 +8,39 @@
>  
>  #include "core.h"
>  
> +static int sst26vf_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
> +{
> +	return -EOPNOTSUPP;
> +}
> +
> +static int sst26vf_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
> +{
> +	if (!ofs && len == nor->params->size)

Nitpick: ofs is not a boolean value. Don't treat it as such. (ofs == 0 
&& len == nor->params->size) makes the intent much clearer.

> +		return spi_nor_global_block_unlock(nor);
> +
> +	return -EOPNOTSUPP;
> +}
> +
> +static int sst26vf_is_locked(struct spi_nor *nor, loff_t ofs, uint64_t len)
> +{
> +	return -EOPNOTSUPP;
> +}
> +
> +static const struct spi_nor_locking_ops sst26vf_locking_ops = {
> +	.lock = sst26vf_lock,
> +	.unlock = sst26vf_unlock,
> +	.is_locked = sst26vf_is_locked,
> +};
> +
> +static void sst26vf_default_init(struct spi_nor *nor)
> +{
> +	nor->params->locking_ops = &sst26vf_locking_ops;
> +}
> +
> +static const struct spi_nor_fixups sst26vf_fixups = {
> +	.default_init = sst26vf_default_init,
> +};
> +
>  static const struct flash_info sst_parts[] = {
>  	/* SST -- large erase sizes are "overlays", "sectors" are 4K */
>  	{ "sst25vf040b", INFO(0xbf258d, 0, 64 * 1024,  8,
> @@ -39,8 +72,9 @@ static const struct flash_info sst_parts[] = {
>  	{ "sst26vf016b", INFO(0xbf2641, 0, 64 * 1024, 32,
>  			      SECT_4K | SPI_NOR_DUAL_READ) },
>  	{ "sst26vf064b", INFO(0xbf2643, 0, 64 * 1024, 128,
> -			      SECT_4K | SPI_NOR_DUAL_READ |
> -			      SPI_NOR_QUAD_READ) },
> +			      SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
> +			      SPI_NOR_HAS_LOCK | SPI_NOR_SWP_IS_VOLATILE)
> +		.fixups = &sst26vf_fixups },
>  };
>  
>  static int sst_write(struct mtd_info *mtd, loff_t to, size_t len,
> -- 
> 2.25.1
> 
> 
> ______________________________________________________
> Linux MTD discussion mailing list
> http://lists.infradead.org/mailman/listinfo/linux-mtd/

-- 
Regards,
Pratyush Yadav
Texas Instruments India

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