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

[<Tudor.Ambarus@xxxxxxxxxxxxx>]

Hi, Alexandre,

On 11/16/2018 03:42 PM, Alexandre Belloni wrote:
> On 16/11/2018 11:57:10+0000, Tudor.Ambarus@xxxxxxxxxxxxx wrote:
>>
>>
>> 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.
>>
> 
> Note that this patch is badly needed for some of our boards. without it,
> they can't reboot properly. I would very much like to see it enter
> upstream and be backported sooner than later.

What flash do the boards use? Does your flash support SFDP 4-Byte Instruction
table? If yes, the following patch should solve your problem indirectly:

https://lore.kernel.org/patchwork/patch/1015036/

You should also apply the following if you want to test it:

https://lore.kernel.org/patchwork/patch/1013294/

Cheers,
ta
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