[PATCH 1/2] dt-bindings: mtd: nand: Macronix: document new binding

[Álvaro Fernández Rojas]

Hi Miquèl,

El vie, 24 mar 2023 a las 10:40, Miquel Raynal
(<miquel.raynal at bootlin.com>) escribió:
>
> Hi Álvaro,
>
> noltari at gmail.com wrote on Thu, 23 Mar 2023 13:45:09 +0100:
>
> > Add new "mxic,disable-block-protection" binding documentation.
> > This binding allows disabling block protection support for those devices not
> > supporting it.
> >
> > Signed-off-by: Álvaro Fernández Rojas <noltari at gmail.com>
> > ---
> >  Documentation/devicetree/bindings/mtd/nand-macronix.txt | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/mtd/nand-macronix.txt b/Documentation/devicetree/bindings/mtd/nand-macronix.txt
> > index ffab28a2c4d1..03f65ca32cd3 100644
> > --- a/Documentation/devicetree/bindings/mtd/nand-macronix.txt
> > +++ b/Documentation/devicetree/bindings/mtd/nand-macronix.txt
> > @@ -16,6 +16,9 @@ in children nodes.
> >  Required NAND chip properties in children mode:
> >  - randomizer enable: should be "mxic,enable-randomizer-otp"
> >
> > +Optional NAND chip properties in children mode:
> > +- block protection disable: should be "mxic,disable-block-protection"
> > +
>
> Besides the fact that nowadays we prefer to see binding conversions to
> yaml before adding anything, I don't think this will fly.
>
> I'm not sure exactly what "disable block protection" means, we
> already have similar properties like "lock" and "secure-regions", not
> sure they will fit but I think it's worth checking.

As explained in 2/2, commit 03a539c7a118 introduced a regression on
Sercomm H500-s (BCM63268) OpenWrt devices with Macronix MX30LF1G18AC
which hangs the device.

This is the log with block protection disabled:
[    0.495831] bcm6368_nand 10000200.nand: there is not valid maps for
state default
[    0.504995] nand: device found, Manufacturer ID: 0xc2, Chip ID: 0xf1
[    0.511526] nand: Macronix MX30LF1G18AC
[    0.515586] nand: 128 MiB, SLC, erase size: 128 KiB, page size:
2048, OOB size: 64
[    0.523516] bcm6368_nand 10000200.nand: detected 128MiB total,
128KiB blocks, 2KiB pages, 16B OOB, 8-bit, BCH-4
[    0.535912] Bad block table found at page 65472, version 0x01
[    0.544268] Bad block table found at page 65408, version 0x01
[    0.954329] 9 fixed-partitions partitions found on MTD device brcmnand.0
...

This is the log with block protection enabled:
[    0.495095] bcm6368_nand 10000200.nand: there is not valid maps for
state default
[    0.504249] nand: device found, Manufacturer ID: 0xc2, Chip ID: 0xf1
[    0.510772] nand: Macronix MX30LF1G18AC
[    0.514874] nand: 128 MiB, SLC, erase size: 128 KiB, page size:
2048, OOB size: 64
[    0.522780] bcm6368_nand 10000200.nand: detected 128MiB total,
128KiB blocks, 2KiB pages, 16B OOB, 8-bit, BCH-4
[    0.539687] Bad block table not found for chip 0
[    0.550153] Bad block table not found for chip 0
[    0.555069] Scanning device for bad blocks
[    0.601213] CPU 1 Unable to handle kernel paging request at virtual
address 10277f00, epc == 8039ce70, ra == 8016ad50
*** Device hangs ***

Enabling macronix_nand_block_protection_support() makes the device
unable to detect the bad block table and hangs it when trying to scan
for bad blocks.

>
> Otherwise, why would you disable the block protection? What does it
> mean exactly? I'm not in favor of a Macronix-specific property here.
>
> Thanks,
> Miquèl

--
Álvaro