Message-ID: <fb42e33b-2ad2-9607-0540-138bfd70c9ba@microchip.com>
Date:   Wed, 20 Jan 2021 13:02:21 +0000
From:   <Tudor.Ambarus@...rochip.com>
To:     <p.yadav@...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

On 1/20/21 2:29 PM, Pratyush Yadav wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> 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.

I agree, will change. Cheers,
ta

> 
>> +             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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