Re: [net-next: PATCH 09/12] Documentation: ACPI: DSD: introduce DSA description

From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Andrew Lunn <andrew@lunn.ch>
Cc: Marcin Wojtas <mw@semihalf.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
	netdev <netdev@vger.kernel.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Len Brown <lenb@kernel.org>,
	vivien.didelot@gmail.com, Florian Fainelli <f.fainelli@gmail.com>,
	Vladimir Oltean <olteanv@gmail.com>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>,
	pabeni@redhat.com,
	Russell King - ARM Linux <linux@armlinux.org.uk>,
	Heiner Kallweit <hkallweit1@gmail.com>,
	Grzegorz Bernacki <gjb@semihalf.com>,
	Grzegorz Jaszczyk <jaz@semihalf.com>,
	Tomasz Nowicki <tn@semihalf.com>,
	Samer El-Haj-Mahmoud <Samer.El-Haj-Mahmoud@arm.com>,
	upstream@semihalf.com
Subject: Re: [net-next: PATCH 09/12] Documentation: ACPI: DSD: introduce DSA description
Date: Wed, 22 Jun 2022 14:04:50 +0300	[thread overview]
Message-ID: <YrL3UtIYjmBiWmuH@smile.fi.intel.com> (raw)
In-Reply-To: <YrLft+BrP2jI5lwp@lunn.ch>

On Wed, Jun 22, 2022 at 11:24:07AM +0200, Andrew Lunn wrote:
> On Wed, Jun 22, 2022 at 11:08:13AM +0200, Marcin Wojtas wrote:
> > wt., 21 cze 2022 o 13:42 Andy Shevchenko
> > <andriy.shevchenko@linux.intel.com> napisał(a):
> > > On Tue, Jun 21, 2022 at 01:18:38PM +0200, Andrew Lunn wrote:
> > > > On Tue, Jun 21, 2022 at 02:09:14PM +0300, Andy Shevchenko wrote:
> > > > > On Mon, Jun 20, 2022 at 09:47:31PM +0200, Andrew Lunn wrote:

...

> > > > > > > +            Memory32Fixed (ReadWrite,
> > > > > > > +                0xf212a200,
> > > > > > > +                0x00000010,
> > > > > >
> > > > > > What do these magic numbers mean?
> > > > >
> > > > > Address + Length, it's all described in the ACPI specification.
> > > >
> > > > The address+plus length of what? This device is on an MDIO bus. As
> > > > such, there is no memory! It probably makes sense to somebody who
> > > > knows ACPI, but to me i have no idea what it means.
> > >
> > > I see what you mean. Honestly I dunno what the device this description is for.
> > > For the DSA that's behind MDIO bus? Then it's definitely makes no sense and
> > > MDIOSerialBus() resources type is what would be good to have in ACPI
> > > specification.
> > 
> > It's not device on MDIO bus, but the MDIO controller's register itself
> 
> Ah. So this is equivalent to
> 
>                 CP11X_LABEL(mdio): mdio@12a200 {
>                         #address-cells = <1>;
>                         #size-cells = <0>;
>                         compatible = "marvell,orion-mdio";
>                         reg = <0x12a200 0x10>;
>                         clocks = <&CP11X_LABEL(clk) 1 9>, <&CP11X_LABEL(clk) 1 5>,
>                                  <&CP11X_LABEL(clk) 1 6>, <&CP11X_LABEL(clk) 1 18>;
>                         status = "disabled";
>                 };
> 
> DT seems a lot more readable, "marvell,orion-mdio" is a good hint that
> device this is. But maybe it is more readable because that is what i'm
> used to.

In ACPI we have _HID and _DDN. _DDN may put a descriptive string.

> Please could you add a lot more comments. Given that nobody currently
> actually does networking via ACPI, we have to assume everybody trying
> to use it is a newbie, and more comments are better than less.

-- 
With Best Regards,
Andy Shevchenko