Re: [PATCH v2 1/2] mtd: spi-nor: core: add flag for doing optional SFDP

From: Esben Haabendal <esben@geanix.com>
To: Tudor Ambarus <tudor.ambarus@linaro.org>
Cc: Pratyush Yadav <pratyush@kernel.org>,
	 Michael Walle <mwalle@kernel.org>,
	 Miquel Raynal <miquel.raynal@bootlin.com>,
	 Richard Weinberger <richard@nod.at>,
	 Vignesh Raghavendra <vigneshr@ti.com>,
	linux-mtd@lists.infradead.org,  linux-kernel@vger.kernel.org,
	 Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Subject: Re: [PATCH v2 1/2] mtd: spi-nor: core: add flag for doing optional SFDP
Date: Thu, 06 Jun 2024 19:13:57 +0200	[thread overview]
Message-ID: <878qziat9m.fsf@geanix.com> (raw)
In-Reply-To: <a379a411-2c9e-4d9d-aa8f-4c4f3463cc27@linaro.org> (Tudor Ambarus's message of "Thu, 6 Jun 2024 14:31:22 +0100")

Tudor Ambarus <tudor.ambarus@linaro.org> writes:

> On 6/3/24 14:09, Esben Haabendal wrote:
>> A dedicated flag for triggering call to
>> spi_nor_sfdp_init_params_deprecated() allows enabling optional SFDP read
>> and parse, with fallback to legacy flash parameters, without having dual,
>> quad or octal parameters set in the legacy flash parameters.
>> 
>> With this, spi-nor flash parts without SFDP that is replaced with a
>> different flash NOR flash part that does have SFDP, but shares the same
>> manufacturer and device ID is easily handled.
>> 
>> Signed-off-by: Esben Haabendal <esben@geanix.com>
>> ---
>>  drivers/mtd/spi-nor/core.c | 3 ++-
>>  drivers/mtd/spi-nor/core.h | 1 +
>>  2 files changed, 3 insertions(+), 1 deletion(-)
>> 
>> diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
>> index 3e1f1913536b..1c4d66fc993b 100644
>> --- a/drivers/mtd/spi-nor/core.c
>> +++ b/drivers/mtd/spi-nor/core.c
>> @@ -2933,7 +2933,8 @@ static void spi_nor_init_params_deprecated(struct spi_nor *nor)
>>  
>>  	spi_nor_manufacturer_init_params(nor);
>>  
>> -	if (nor->info->no_sfdp_flags & (SPI_NOR_DUAL_READ |
>> +	if (nor->info->no_sfdp_flags & (SPI_NOR_TRY_SFDP |
>
> I don't like that we update deprecated methods. The solution though is
> elegant.

Maybe we should un-deprecate it? I don't understand why it should be
deprecated. It obviously has a valid purpose.

>> +					SPI_NOR_DUAL_READ |
>>  					SPI_NOR_QUAD_READ |
>>  					SPI_NOR_OCTAL_READ |
>>  					SPI_NOR_OCTAL_DTR_READ))
>> diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h
>> index 442786685515..77f61a984cb3 100644
>> --- a/drivers/mtd/spi-nor/core.h
>> +++ b/drivers/mtd/spi-nor/core.h
>> @@ -535,6 +535,7 @@ struct flash_info {
>>  	u8 no_sfdp_flags;
>>  #define SPI_NOR_SKIP_SFDP		BIT(0)
>>  #define SECT_4K				BIT(1)
>> +#define SPI_NOR_TRY_SFDP		BIT(2)
>>  #define SPI_NOR_DUAL_READ		BIT(3)
>>  #define SPI_NOR_QUAD_READ		BIT(4)
>>  #define SPI_NOR_OCTAL_READ		BIT(5)
>> 

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