Re: [PATCH 2/2] mtd: rawnand: brcmnand: support "no-wp" DT property

Florian Fainelli
2021-11-03T18:10:11Z

On 11/3/21 11:03 AM, Rafał Miłecki wrote:
> On 2021-11-03 18:50, Florian Fainelli wrote:
>> On 11/3/21 8:11 AM, Rafał Miłecki wrote:
>>> From: Rafał Miłecki <rafal@milecki.pl>
>>>
>>> Some boards may use WP-capable controller but still have WP not
>>> connected. This change fixes:
>>> [    1.175550] bcm63138_nand ff801800.nand: timeout on status poll
>>> (expected c0000040 got c00000c0)
>>> [    1.184524] bcm63138_nand ff801800.nand: nand #WP expected on
>>> [    1.285547] bcm63138_nand ff801800.nand: timeout on status poll
>>> (expected c0000040 got c00000c0)
>>> [    1.294516] bcm63138_nand ff801800.nand: nand #WP expected on
>>> [    1.395548] bcm63138_nand ff801800.nand: timeout on status poll
>>> (expected c0000040 got c00000c0)
>>> [    1.404517] bcm63138_nand ff801800.nand: nand #WP expected on
>>>
>>> Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
>>> ---
>>>  drivers/mtd/nand/raw/brcmnand/brcmnand.c | 3 ++-
>>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
>>> b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
>>> index f75929783b94..8b6167457f0c 100644
>>> --- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
>>> +++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
>>> @@ -714,7 +714,8 @@ static int brcmnand_revision_init(struct
>>> brcmnand_controller *ctrl)
>>>      if (ctrl->nand_version >= 0x0500)
>>>          ctrl->features |= BRCMNAND_HAS_1K_SECTORS;
>>>
>>> -    if (ctrl->nand_version >= 0x0700)
>>> +    if (ctrl->nand_version >= 0x0700 &&
>>> +        !of_property_read_bool(ctrl->dev->of_node, "no-wp"))
>>>          ctrl->features |= BRCMNAND_HAS_WP;
>>
>> Should not this be a logical OR here or rather, should it be moved out
>> of the check on ctrl->nand_version entirely? What revision of the NAND
>> controller do you have on that chip?
>
> It's NAND controller version 0x0701 (v7.1) and I think it's correct.
>
> I think we want WP enabled on rev 7.0+ unless it was explicitly disabled.

True, I somehow got confused about the negative logic, so maybe we need
to combine the logic of all of these lines into a single one:

if ((ctrl->nand_version >= 0x700 ||
of_property_read_bool(ctrl->dev->of_node, "brcm,nand-has-wp")) &&
!of_property_read_bool(ctrl->dev->of_node, "no-wp")

such that it is clearer, Kamal, what do you think?
--
Florian