linux-kernel - Re: [PATCH 6/7] mtd: spi-nor: Rework the SPI NOR lock/unlock logic

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Message-ID: <d02fc366-55b6-f698-2419-f277e88dfe02@microchip.com>
Date:   Mon, 5 Aug 2019 08:00:00 +0000
From:   <Tudor.Ambarus@...rochip.com>
To:     <vigneshr@...com>, <boris.brezillon@...labora.com>,
        <marek.vasut@...il.com>
CC:     <dwmw2@...radead.org>, <computersforpeace@...il.com>,
        <miquel.raynal@...tlin.com>, <richard@....at>,
        <linux-mtd@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
        <boris.brezillon@...tlin.com>
Subject: Re: [PATCH 6/7] mtd: spi-nor: Rework the SPI NOR lock/unlock logic



On 08/04/2019 05:36 PM, Vignesh Raghavendra wrote:
> External E-Mail
> 
> 
> Hi Tudor,
> 
> On 31-Jul-19 2:33 PM, Tudor.Ambarus@...rochip.com wrote:
>> From: Boris Brezillon <boris.brezillon@...tlin.com>
>>
>> Move the locking hooks in a separate struct so that we have just
>> one field to update when we change the locking implementation.
>>
>> stm_locking_ops, the legacy locking operations, can be overwritten
>> later on by implementing manufacturer specific default_init() hooks.
>>
>> Signed-off-by: Boris Brezillon <boris.brezillon@...tlin.com>
>> [tudor.ambarus@...rochip.com: use ->default_init() hook]
>> Signed-off-by: Tudor Ambarus <tudor.ambarus@...rochip.com>
> 
> [...]
> 
>> @@ -1782,7 +1788,7 @@ static int spi_nor_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
>>  	if (ret)
>>  		return ret;
>>  
>> -	ret = nor->flash_is_locked(nor, ofs, len);
>> +	ret = nor->locking_ops->is_locked(nor, ofs, len);
>>  
>>  	spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_LOCK);
>>  	return ret;
>> @@ -4805,6 +4811,10 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
>>  	nor->quad_enable = spansion_quad_enable;
>>  	nor->set_4byte = spansion_set_4byte;
>>  
>> +	/* Default locking operations. */
>> +	if (info->flags & SPI_NOR_HAS_LOCK)
>> +		nor->locking_ops = &stm_locking_ops;
>> +
> 
> This condition is different than how lock/unlock ops are populated
> today. We would need to add SPI_NOR_HAS_LOCK to all SNOR_MFR_ST and
> SNOR_MFR_MICRON entries to be backward compatible or keep the condition
> as is.

Will do, thanks!

> 
>>  	/* Init flash parameters based on flash_info struct and SFDP */
>>  	spi_nor_init_params(nor, &params);
>>  
>> @@ -4819,21 +4829,6 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
>>  	mtd->_read = spi_nor_read;
>>  	mtd->_resume = spi_nor_resume;
>>  
>> -	/* NOR protection support for STmicro/Micron chips and similar */
>> -	if (JEDEC_MFR(info) == SNOR_MFR_ST ||
>> -	    JEDEC_MFR(info) == SNOR_MFR_MICRON ||
>> -	    info->flags & SPI_NOR_HAS_LOCK) {
>> -		nor->flash_lock = stm_lock;
>> -		nor->flash_unlock = stm_unlock;
>> -		nor->flash_is_locked = stm_is_locked;
>> -	}
>> -
> 
> [...]
> 
>> diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
>> index a434ab7a53e6..bd68ec5a10e7 100644
>> --- a/include/linux/mtd/spi-nor.h
>> +++ b/include/linux/mtd/spi-nor.h
>> @@ -425,9 +425,23 @@ struct spi_nor {
>>  	int (*set_4byte)(struct spi_nor *nor, bool enable);
>>  	int (*clear_sr_bp)(struct spi_nor *nor);
>>  
>> +	const struct spi_nor_locking_ops *locking_ops;
>> +
> 
> Also, to be consistent, document this new member.

Will do.
> 
> 
>>  	void *priv;
>>  };
>>  
>> +/**
>> + * struct spi_nor_locking_ops - SPI NOR locking methods
>> + * @lock: lock a region of the SPI NOR
>> + * @unlock: unlock a region of the SPI NOR
>> + * @is_locked: check if a region of the SPI NOR is completely locked
>> + */
>> +struct spi_nor_locking_ops {
>> +	int (*lock)(struct spi_nor *nor, loff_t ofs, uint64_t len);
>> +	int (*unlock)(struct spi_nor *nor, loff_t ofs, uint64_t len);
>> +	int (*is_locked)(struct spi_nor *nor, loff_t ofs, uint64_t len);
> 
> checkpatch does not like uint64_t. Please changes these to size_t

This respects what struct mtd_info is expecting:

        int (*_lock) (struct mtd_info *mtd, loff_t ofs, uint64_t len);
        int (*_unlock) (struct mtd_info *mtd, loff_t ofs, uint64_t len);
        int (*_is_locked) (struct mtd_info *mtd, loff_t ofs, uint64_t len);

I haven't seen the warnings, would you mind pasting them?
./scripts/checkpatch.pl --strict 6-7-mtd-spi-nor-Rework-the-SPI-NOR-lock-unlock-logic.patch
total: 0 errors, 0 warnings, 0 checks, 102 lines checked

6-7-mtd-spi-nor-Rework-the-SPI-NOR-lock-unlock-logic.patch has no obvious style problems and is ready for submission.

Cheers,
ta

> 
> Regards
> Vignesh
> 
> 
>> +};
>> +
>>  static u64 __maybe_unused
>>  spi_nor_region_is_last(const struct spi_nor_erase_region *region)
>>  {
>>