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Subject: Re: [PATCH v3] mtd: spi-nor: fix nor->addr_width when its value
 configured from SFDP does not match the actual width
To:     <Tudor.Ambarus@microchip.com>, <liu.xiang6@zte.com.cn>,
        <linux-mtd@lists.infradead.org>
CC:     <bbrezillon@kernel.org>, <richard@nod.at>,
        <linux-kernel@vger.kernel.org>, <marek.vasut@gmail.com>,
        <liuxiang_1999@126.com>, <computersforpeace@gmail.com>,
        <dwmw2@infradead.org>, <nagasure@xilinx.com>
References: <1554018157-10860-1-git-send-email-liu.xiang6@zte.com.cn>
 <5ffc9e32-ff69-9819-7bfd-ad9f793bb629@microchip.com>
From:   Vignesh Raghavendra <vigneshr@ti.com>
Message-ID: <aea913e6-d168-32dd-1913-f1796905f98e@ti.com>
Date:   Mon, 24 Jun 2019 16:29:56 +0530
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On 22/06/19 5:19 PM, Tudor.Ambarus@microchip.com wrote:
> Hi, Liu,
> 
> On 03/31/2019 10:42 AM, Liu Xiang wrote:
> 
>> Some is25lp256 get BFPT_DWORD1_ADDRESS_BYTES_3_ONLY from BFPT table for
>> address width. But in actual fact the flash can support 4-byte address.
>> So we should fix it.
> 
> It's better to be imperative. Substitute "So we should fix it" with something
> like "Use a post bfpt fixup hook to overwrite the address width advertised by
> the BFPT".
> 
>>
> 
> We'll need a fixes tag here.> Suggested-by: Boris Brezillon <bbrezillon@kernel.org>
>> Suggested-by: Vignesh Raghavendra <vigneshr@ti.com>
> 
> When? If they didn't explicitly suggested this approach, lets drop the S-b tags.
> 

IIRC, this was actually Boris's patch. No need for my S-b tag me :)

Regards
Vignesh

>> Signed-off-by: Liu Xiang <liu.xiang6@zte.com.cn>
>> ---
>>
>> Changes in v3:
>>  add a fixup for is25lp256 to solve the address width problem.
>>
>>  drivers/mtd/spi-nor/spi-nor.c | 25 ++++++++++++++++++++++++-
>>  1 file changed, 24 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
>> index 6e13bbd..d252a66 100644
>> --- a/drivers/mtd/spi-nor/spi-nor.c
>> +++ b/drivers/mtd/spi-nor/spi-nor.c
>> @@ -1682,6 +1682,28 @@ static int sr2_bit7_quad_enable(struct spi_nor *nor)
>>  		.flags = SPI_NOR_NO_FR | SPI_S3AN,
>>  
>>  static int
>> +is25lp256_post_bfpt_fixups(struct spi_nor *nor,
>> +			   const struct sfdp_parameter_header *bfpt_header,
>> +			   const struct sfdp_bfpt *bfpt,
>> +			   struct spi_nor_flash_parameter *params)
>> +{
>> +	/*
>> +	 * IS25LP256 supports 4B opcodes.
>> +	 * Unfortunately, some devices get BFPT_DWORD1_ADDRESS_BYTES_3_ONLY
>                             ^ which devices, did you get a list from issi?
> 
>> +	 * from BFPT table for address width. We should fix it.
> 
> How about "IS25LP256 supports 4B opcodes, but the BFPT advertises a
> BFPT_DWORD1_ADDRESS_BYTES_3_ONLY address width. Overwrite the address width
> advertised by the BFPT."
> 
>> +	 */
>> +	if ((bfpt->dwords[BFPT_DWORD(1)] & BFPT_DWORD1_ADDRESS_BYTES_MASK) ==
>> +		BFPT_DWORD1_ADDRESS_BYTES_3_ONLY)
>> +		nor->addr_width = 4;
>> +
>> +	return 0;
>> +}
>> +
>> +static struct spi_nor_fixups is25lp256_fixups = {
> 
> Naga will use "is25lp256_fixups" for the is25wp256 too, but it's not the case to
> change the name yet. All good here.
> 
> I really want to have this in next, can I have an update in the next few days?
> 
> Cheers,
> ta
> 

-- 
Regards
Vignesh