linux-kernel - Re: [PATCH 22/43] dt-bindings: mtd: add DT bindings for ts7250 nand

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <783af132a3eab7c79c95de5113c6bdb0adce19b5.camel@maquefel.me>
Date:   Mon, 15 May 2023 18:48:31 +0300
From:   Nikita Shubin <nikita.shubin@...uefel.me>
To:     Miquel Raynal <miquel.raynal@...tlin.com>
Cc:     Arnd Bergmann <arnd@...nel.org>, Linus Walleij <linusw@...nel.org>,
        Alexander Sverdlin <alexander.sverdlin@...il.com>,
        Richard Weinberger <richard@....at>,
        Vignesh Raghavendra <vigneshr@...com>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Lukasz Majewski <lukma@...x.de>, linux-mtd@...ts.infradead.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 22/43] dt-bindings: mtd: add DT bindings for ts7250 nand

Hello Miquel!

Thank you for looking into it.

On Tue, 2023-05-02 at 11:48 +0200, Miquel Raynal wrote:
> Hi Nikita,
> 
> nikita.shubin@...uefel.me wrote on Mon, 24 Apr 2023 15:34:38 +0300:
> 
> > Add YAML bindings for ts7250 NAND.
> > 
> > Signed-off-by: Nikita Shubin <nikita.shubin@...uefel.me>
> > ---
> >  .../bindings/mtd/technologic,nand.yaml        | 56
> > +++++++++++++++++++
> >  1 file changed, 56 insertions(+)
> >  create mode 100644
> > Documentation/devicetree/bindings/mtd/technologic,nand.yaml
> > 
> > diff --git
> > a/Documentation/devicetree/bindings/mtd/technologic,nand.yaml
> > b/Documentation/devicetree/bindings/mtd/technologic,nand.yaml
> > new file mode 100644
> > index 000000000000..3234d93a1c21
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/mtd/technologic,nand.yaml
> > @@ -0,0 +1,56 @@
> > +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/mtd/technologic,nand.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Technologic Systems NAND controller
> > +
> > +maintainers:
> > +  - Lukasz Majewski <lukma@...x.de>
> > +
> > +properties:
> > +  compatible:
> > +    items:
> > +      - const: technologic,ts7200-nand
> 
> would -nand-controller instead of -nand work as a suffix here?
> 
> You mention ts7250 in the title, should we have a more specific
> compatible than ts7200 as well?
> 
> I see by looking at the mtd patch that you actually try to match
> both,
> so they should both be defined in the bindings.
> 
> > +      - const: gen_nand
> 
> This is a old hack for very simple controllers (converted to DT
> probing
> 12 years ago). The logic used by this driver has been deprecated for
> like 10 years and does not really apply to modern APIs. I would
> really
> like to keep this driver contained with platform data coming from
> arch/
> data only.
> 
> I suggest you create a real NAND controller driver based on the
> generic one (should not be very complex, just duplicate the code so
> the
> migration to the up-to-date API is eased) and you flag it as "must be
> updated to ->exec_op() somehow. This way if someone starts the
> conversion, it does not need to cope with the 5 other users of the
> generic driver which anyway share nothing in common besides the
> deprecated ->cmd_ctrl() backbone.
> 
> I read the comments on the cover letter, people are kind of pushing
> on
> having this merged quickly. I am fine accepting a legacy controller
> driver and migrating it to ->exec_op() later, but the current driver
> conversion does not fit the approach taken years ago towards a
> cleaner
> mtd tree.

Did you mean that i should at least implement legacy nand controller,
like, for example, Xway (xway_nand.c) ?:

        data->chip.legacy.cmd_ctrl = xway_cmd_ctrl;
        data->chip.legacy.dev_ready = xway_dev_ready;
        data->chip.legacy.select_chip = xway_select_chip;
        data->chip.legacy.write_buf = xway_write_buf;
        data->chip.legacy.read_buf = xway_read_buf;
        data->chip.legacy.read_byte = xway_read_byte;
        data->chip.legacy.chip_delay = 30;

And the best solution would be switching to exec_op completely ?

> 
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +  '#address-cells': true
> > +  '#size-cells': true
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +
> > +unevaluatedProperties: true
> > +
> > +examples:
> > +  - |
> > +    nand-parts@0 {
> > +      compatible = "technologic,ts7200-nand", "gen_nand";
> > +      reg = <0x60000000 0x8000000>;
> > +      #address-cells = <1>;
> > +      #size-cells = <1>;
> > +
> > +      partition@0 {
> > +        label = "TS-BOOTROM";
> > +        reg = <0x00000000 0x00020000>;
> > +        read-only;
> > +      };
> 
> Partitions are not useful here, but if you want them, use the
> partitions container instead, please.
> 
> > +
> > +      partition@...00 {
> > +        label = "Linux";
> > +        reg = <0x00020000 0x07d00000>;
> > +      };
> > +
> > +      partition@...0000 {
> > +        label = "RedBoot";
> > +        reg = <0x07d20000 0x002e0000>;
> > +        read-only;
> > +      };
> > +    };
> > +
> > +...
> 
> 
> Thanks,
> Miquèl