linux-kernel - Re: [PATCH v5 05/23] mailbox: Allow controller specific mapping using fwnode

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Message-ID: <CAK9=C2Xhkfk4WZeD2gVCoJxeRHAuYjSfwx_zUHvVBqOQPLV7Lg@mail.gmail.com>
Date: Wed, 18 Jun 2025 09:38:46 +0530
From: Anup Patel <apatel@...tanamicro.com>
To: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc: Michael Turquette <mturquette@...libre.com>, Stephen Boyd <sboyd@...nel.org>, 
	Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
	Jassi Brar <jassisinghbrar@...il.com>, Thomas Gleixner <tglx@...utronix.de>, 
	"Rafael J . Wysocki" <rafael@...nel.org>, Mika Westerberg <mika.westerberg@...ux.intel.com>, 
	Linus Walleij <linus.walleij@...aro.org>, Bartosz Golaszewski <brgl@...ev.pl>, 
	Uwe Kleine-König <ukleinek@...nel.org>, 
	Palmer Dabbelt <palmer@...belt.com>, Paul Walmsley <paul.walmsley@...ive.com>, 
	Len Brown <lenb@...nel.org>, Sunil V L <sunilvl@...tanamicro.com>, 
	Rahul Pathak <rpathak@...tanamicro.com>, Leyfoon Tan <leyfoon.tan@...rfivetech.com>, 
	Atish Patra <atish.patra@...ux.dev>, Andrew Jones <ajones@...tanamicro.com>, 
	Samuel Holland <samuel.holland@...ive.com>, Anup Patel <anup@...infault.org>, 
	linux-clk@...r.kernel.org, devicetree@...r.kernel.org, 
	linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 05/23] mailbox: Allow controller specific mapping using fwnode

On Wed, Jun 11, 2025 at 9:05 PM Andy Shevchenko
<andriy.shevchenko@...ux.intel.com> wrote:
>
> On Wed, Jun 11, 2025 at 11:52:20AM +0530, Anup Patel wrote:
> > Introduce optional fw_node() callback which allows a mailbox controller
> > driver to provide controller specific mapping using fwnode.
> >
> > The Linux OF framework already implements fwnode operations for the
> > Linux DD framework so the fw_xlate() callback works fine with device
> > tree as well.
>
> ...
>
> >  struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
> >  {
> > +     struct fwnode_reference_args fwspec;
>
> Define
>
>         struct fwnode_handle *fwnode;
>
>
> >       struct device *dev = cl->dev;
>
> This better to be just a declaration.
>
> >       struct mbox_controller *mbox;
> >       struct of_phandle_args spec;
> >       struct mbox_chan *chan;
> > +     unsigned int i;
> >       int ret;
>
> With the above the below will look like...
>
> > -     if (!dev || !dev->of_node) {
> > -             pr_debug("%s: No owner device node\n", __func__);
> > +     if (!dev || !dev_fwnode(dev)) {
> > +             pr_debug("No owner %s\n", dev ? "fwnode" : "device");
> >               return ERR_PTR(-ENODEV);
> >       }
> >
> > -     ret = of_parse_phandle_with_args(dev->of_node, "mboxes", "#mbox-cells",
> > -                                      index, &spec);
> > +     ret = fwnode_property_get_reference_args(dev_fwnode(dev), "mboxes",
> > +                                              "#mbox-cells", 0, index, &fwspec);
> >       if (ret) {
> >               dev_err(dev, "%s: can't parse \"mboxes\" property\n", __func__);
> >               return ERR_PTR(ret);
> >       }
>
> ...this
>
>         dev = cl->dev;
>         if (!dev) {
>                 pr_debug("No owner device\n");
>                 return ERR_PTR(-ENODEV);
>         }
>
>         fwnode = dev_fwnode(dev);
>         if (!fwnode) {
>                 dev_dbg(dev, "No owner fwnode\n");
>                 return ERR_PTR(-ENODEV);
>         }
>
>         ret = fwnode_property_get_reference_args(fwnode, "mboxes",
>                                                  "#mbox-cells", 0, index, &fwspec);
>         if (ret) {
>                 dev_err(dev, "%s: can't parse \"mboxes\" property\n", __func__);
>
> You may save a few bytes by doing it as
>
>                 dev_err(dev, "%s: can't parse \"%s\" property\n", __func__, "mboxes");
>
>                 return ERR_PTR(ret);
>         }
>
> > +     spec.np = to_of_node(fwspec.fwnode);
> > +     spec.args_count = fwspec.nargs;
> > +     for (i = 0; i < spec.args_count; i++)
> > +             spec.args[i] = fwspec.args[i];
> > +
> >       scoped_guard(mutex, &con_mutex) {
> >               chan = ERR_PTR(-EPROBE_DEFER);
> > -             list_for_each_entry(mbox, &mbox_cons, node)
> > -                     if (mbox->dev->of_node == spec.np) {
> > +             list_for_each_entry(mbox, &mbox_cons, node) {
>
> > +                     if (mbox->fw_xlate && dev_fwnode(mbox->dev) == fwspec.fwnode) {
>
> We have a helper device_match_fwnode()
>
> > +                             chan = mbox->fw_xlate(mbox, &fwspec);
> > +                             if (!IS_ERR(chan))
> > +                                     break;
> > +                     } else if (mbox->of_xlate && mbox->dev->of_node == spec.np) {
>
> No need to check OF node (again). Instead refactor as
>
>                         if (device_match_fwnode(...)) {
>                                 if (fw_xlate) {
>                                         ...
>                                 } else if (of_xlate) {
>                                         ...
>                                 }
>                         }
>

Okay, I will update like you suggested.

Regards,
Anup