Re: [PATCH v3 2/2] mtd: spi-nor: Use 4B opcodes when the NOR advertises both 3B and 4B

[<Tudor.Ambarus@xxxxxxxxxxxxx>]

On 11/09/2018 12:49 PM, Tudor.Ambarus@xxxxxxxxxxxxx wrote:
> 
> 
> On 10/31/2018 04:45 PM, Boris Brezillon wrote:
>> When the NOR supports 4 bytes opcodes we should use those instead of
>> switching the flash in 4-bytes mode. This way, we don't have to restore
>> the addressing mode when resetting the board.
>>
>> Reported-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
>> Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxx>
>> Tested-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
>> Reviewed-by: Cyrille Pitchen <cyrille.pitchen@xxxxxxxxxx>
> 
> Reviewed-by: Tudor Ambarus <tudor.ambarus@xxxxxxxxxxxxx>
> 

I propose to stall this patch for a week or so, until we will have a clearer
view on how are defined the flashes that don't have 4B opcodes, but can enter
the 4-Byte mode on command.

>> ---
>> Changes in v3:
>> - Add Alexandre R-b+T-b
>> - Add Cyrille R-b
>>
>> Changes in v2
>> - None
>> ---
>>  drivers/mtd/spi-nor/spi-nor.c | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
>> index 798915b5c2b0..b20bc4b36f0f 100644
>> --- a/drivers/mtd/spi-nor/spi-nor.c
>> +++ b/drivers/mtd/spi-nor/spi-nor.c
>> @@ -2643,6 +2643,7 @@ static int spi_nor_parse_bfpt(struct spi_nor *nor,
>>  		break;
>>  
>>  	case BFPT_DWORD1_ADDRESS_BYTES_4_ONLY:
>> +	case BFPT_DWORD1_ADDRESS_BYTES_3_OR_4:
>>  		nor->flags |= SNOR_F_4B_OPCODES;


Maybe we will also want to check that BFPT DWORD16[31:24] has value xx1x_xxxxb -
it indicates that 4B opcodes are supported.

Cheers,
ta

>>  		nor->addr_width = 4;
>>  		break;
>>
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